Search

High-end CNC machine tools' primary transmission mechanism is a high-speed electric spindle. Thermal displacement of the spindle occurs as a result of heat created inside the spindle during transmission, which has an impact on the machining precision of high-end CNC machine tools. Establishing a high-precision motorized spindle simulation model is crucial because it serves as a foundation for optimizing and testing the motorized spindle's construction and material, adjusting for thermal errors, and estimating its life. The thermal-solid coupling model of the motorized spindle is created by Ansys based on the experimental data of temperature and thermal displacement of the A02 motorized spindle and in accordance with the boundary conditions. The accuracy of front and rear bearings is 93.42% and 90.52%, respectively, when compared to experimental data, and the accuracy of axial thermal displacement is 95.16%. Finally, the motorized spindle is optimized to extend its service life after the thermal displacement, stress, and strain of the bearing are model.

The coprevalence of chronic heart failure (CHF) and depression is 10%-79%, the pathogenesis of these two diseases is related to the activation of immune inflammatory system, insulin resistance and intestinal flora imbalance, and relevant regulation is bidirectional and complex. There is a lack of efficient drugs for both CHF and depression recommended by available diagnosis and treatment guidelines and present clinical practice. But it has recently been reported that some drugs (sacubitril/valsartan, new antidepressants, shensongyangxin and qiliqiangxin capsules, regulators of the intestinal flora) may be partially effective for CHF with depression.We reviewed the mechanism of coexistence and pharmaceutical treatment of CHF and depression, providing new ideas and evidence for clinical diagnosis and treatment of CHF and depression.

Aiming at the scenario of coordinated attack by gliding-guided projectiles in multi-artillery-salvo-shooting to strike fixed targets, the trajectory planning problem for collaboration schemes focusing on projectile groups is investigated to fully leverage the overall control capability and amplify the strike outcomes. Firstly, considering the differences in focal points and trajectory characteristics of fighting scheme when engaging targets at various distances, operational zone for gliding-guided projectiles is divided, and on this basis, a full trajectory cooperative programming model with optimization indicators varying by zone is established. Secondly, in response to the challenges posed by combat formation configurations in practical warfare, a universally applicable and straightforward method for delineating the scope of collaboration is introduced. Then, to overcome the restrictions pertaining to applicability or optimally encountered by existing methods of collaboration within multi-stage planning contexts, a bi-level adaptive cooperation strategy in proposed. Finally, the influence of additional constrains introduced by specific operational tasks on both the allocation of operational zone and the extent of cooperation in analyzed. Simulation results show that the proposed method can swiftly and effectively ascertain variable operating scenarios, thus aiding in combat formation arrangements; additionally, compared with conventional distributed strategies, it in evident that the proposed collaborative strategy yields superior trajectories within various operational zones. [ABSTRACT FROM AUTHOR]

Multi-source fusion constitutes a research focus in the navigation domain. This article focuses on the online estimation of the mounting angles between the body frame and vehicle frame within low-cost embedded vehicle navigation modules and the lever arm between the global satellite navigation system (GNSS) antenna/odometer and the inertial measurement unit (IMU). An online mounting angle error estimation algorithm, using odometers and IMU speeds, has been developed to estimate the angle errors while vehicles are in motion. At the same time, an online estimation algorithm model for the GNSS antenna lever arm and odometer lever arm was constructed. These two types of lever arms are used as the estimated states, and then Kalman filters are used to estimate them. The algorithm can simultaneously estimate the IMU mounting angle error, GNSS antenna arm, and odometer arm online. The experimental outcomes demonstrate that the lever arm estimation algorithm presented herein is effective for tactical and MEMS-level inertial navigation, with an estimation error of less than 2 cm. Meanwhile, the proposed online estimation of the mounting angle algorithm has an accuracy comparable to that of the post-processing algorithm. After making up the mounting angle and lever arm, we found that the position and speed precision of the multi-source fusion navigation systems were significantly improved. The results indicate that the proposed online estimation of mounting angle error and lever arm algorithm are effective and may promote the practical and widespread application of integrated navigation systems in vehicles. It solves the shortcomings of traditional methods, including the cumbersome and inaccurate manual measurement of the lever arm. It provides a technical solution for developing a more accurate and convenient low-cost vehicle navigation module. [ABSTRACT FROM AUTHOR]

In this study, we proposed an improved Harris Hawks Optimization (IHHO) algorithm based on the Sobol sequence, Whale Optimization Algorithm (WOA), and t-distribution perturbation. The improved IHHO algorithm was then used to optimize the BP neural network, resulting in the IHHO-BP model. This model was employed to predict the bonding strength of heat-treated wood under varying conditions of temperature, time, feed rate, cutting speed, and grit size. To validate the effectiveness and accuracy of the proposed model, it was compared with the original BP neural network model, WOA-BP, and HHO-BP benchmark models. The results showed that the IHHO-BP model reduced the Mean Absolute Error (MAE), Root Mean Square Error (RMSE), and Mean Absolute Percentage Error (MAPE) by at least 51.16%, 40.38%, and 51.93%, respectively, while increasing the coefficient of determination (R2) by at least 10.85%. This indicates significant model optimization, enhanced generalization capability, and higher prediction accuracy, better meeting practical engineering needs. Predicting the bonding strength of heat-treated wood using this model can reduce production costs and consumption, thereby significantly improving production efficiency. [ABSTRACT FROM AUTHOR]

In order to study the missile separation safety under the condition of full envelope launch, a new type of double parallelogram ejection configuration is adopted in this paper. The combined flexible multi-body launching dynamics simulation method based on ABAQUS and ADAMS is used to obtain the missile separation velocity, angular velocity, overload, dynamic load of key components and lateral deformation of missile carrier system. The simulation results show that the lateral overload has a significant impact on the separation safety of missile carrier and the structural compatibility of weapon and carrier. On this basis, a method to optimize the lateral deformation of missile carrier system is proposed.

Due to constraints in launch platforms and cost, the maneuverability of gliding-guided projectiles is limited, necessitating a rational design of their trajectory schemes. To reduce the sensitivity of trajectory schemes to uncertainties while ensuring compatibility between flight schemes and guidance control systems and fully exploiting the control capability of the projectile, a closed-loop robust trajectory planning method is proposed. Models of major uncertain factors and state deviation at the control start point are established. Based on the NIPCE method, the stochastic dynamic model is transformed into a high-dimensional deterministic model with PCE coefficients as state variables, and the uncertainty propagation law is obtained. A PID algorithm is employed to design a tracking guidance law based on position error feedback, and open-loop and closed-loop robust trajectory planning models are established accordingly. The optimal control problem is solved by transforming it into a nonlinear programming problem using the direct shooting method. Our simulation results indicate that the NIPCE method can significantly improve the computational efficiency of uncertainty propagation while ensuring accuracy; compared with parallel MCS, the computation time is reduced by 96.8%. Open-loop robust planning can effectively mitigate the sensitivity of gliding trajectories to uncertainties (the standard deviations of terminal altitude and lateral deviations are reduced by 23.6% and 35.3%, respectively, compared to deterministic planning) but cannot completely eliminate terminal dispersion. Closed-loop robust planning effectively improves control effort consumption on the basis of open-loop planning. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) is a naturally occurring toxic heavy metal that adversely affects plant germination, growth, and development. While the effects of Cd have been described on many crop species including rice, maize, wheat and barley, few studies are available on cadmium's effect on Tartary buckwheat which is a traditional grain in China. We examined nine genotypes and found that 30 µM of Cd reduced the root length in seedlings by between 4 and 44% and decreased the total biomass by 7 to 31%, compared with Cd-free controls. We identified a significant genotypic variation in sensitivity to Cd stress. Cd treatment decreased the total root length and the emergence and growth of lateral roots, and these changes were significantly greater in the Cd-sensitive genotypes than in tolerant genotypes. Cd resulted in greater wilting and discoloration in sensitive genotypes than in tolerant genotypes and caused more damage to the structure of root and leaf cells. Cd accumulated in the roots and shoots, but the concentrations in the sensitive genotypes were significantly greater than in the more tolerant genotypes. Cd treatment affected nutrient uptake, and the changes in the sensitive genotypes were greater than those in the tolerant genotypes, which could maintain their concentrations closer to the control levels. The induction of SOD, POD, and CAT activities in the roots and shoots was significantly greater in the tolerant genotypes than in the sensitive genotypes. We demonstrated that Cd stress reduced root and shoot growth, decreased plant biomass, disrupted nutrient uptake, altered cell structure, and managed Cd-induced oxidative stress differently in the sensitive and tolerant genotypes of Tartary buckwheat. [ABSTRACT FROM AUTHOR]

Using detailed data on company visits by Chinese mutual funds, we provide direct evidence of mutual fund information acquisition activities and the consequent informational advantages mutual funds establish in local firms. Mutual funds are more likely to visit local and nearby firms both in and outside of their portfolios, but the ease of travel between fund and firm locations can substantially alleviate geographic distance constraints. Company visits by mutual funds are strongly associated with both fund trading activities and fund trading performance. Our results show that geographic constraints and costly information acquisition amplify information asymmetry in financial markets. [ABSTRACT FROM AUTHOR]

Myocardial ischemia/reperfusion (I/R) injury is the leading cause of death worldwide. Ginsenoside Rd (GRd) has cardioprotective properties but its efficacy and mechanism of action in myocardial I/R injury have not been clarified. This study investigated GRd as a potent therapeutic agent for myocardial I/R injury. Oxygen-glucose deprivation and reperfusion (OGD/R) and left anterior descending (LAD) coronary artery ligation were used to establish a myocardial I/R injury model in vitro and in vivo. In vivo, GRd significantly reduced the myocardial infarct size and markers of myocardial injury and improved the cardiac function in myocardial I/R injury mice. In vitro, GRd enhanced cell viability and protected the H9c2 rat cardiomyoblast cell line from OGD-induced injury GRd. The network pharmacology analysis predicted 48 potential targets of GRd for the treatment of myocardial I/R injury. GO and KEGG enrichment analysis indicated that the cardioprotective effects of GRd were closely related to inflammation and apoptosis mediated by the PI3K/Akt signaling pathway. Furthermore, GRd alleviated inflammation and cardiomyocyte apoptosis in vivo and inhibited OGD/R-induced apoptosis and inflammation in cardiomyocytes. GRd also increased PI3K and Akt phosphorylation, suggesting activation of the PI3K/Akt pathway, whereas LY294002, a PI3K inhibitor, blocked the GRd-induced inhibition of OGD/R-induced apoptosis and inflammation in H9c2 cells. The therapeutic effect of GRd in vivo and in vitro against myocardial I/R injury was primarily dependent on PI3K/Akt pathway activation to inhibit inflammation and cardiomyocyte apoptosis. This study provides new evidence for the use of GRd as a cardiovascular drug. [ABSTRACT FROM AUTHOR]