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In bearings-only target tracking, the pseudo-linear Kalman filter (PLKF) attracts much attention because of its stability and its low computational burden. However, the PLKF’s measurement vector and the pseudo-linear noise are correlated, which makes it suffer from bias problems. Although the bias-compensated PLKF (BC–PLKF) and the instrumental variable-based PLKF (IV–PLKF) can eliminate the bias, they only work well when the target behaves with non-manoeuvring movement. To extend the PLKF to the manoeuvring target tracking scenario, an unbiased PLKF (UB–PLKF) algorithm, which splits the noise away from the measurement vector directly, is proposed. Based on the results of the UB–PLKF, we also propose its velocity-constrained version (VC–PLKF) to further improve the performance. Simulations show that the UB–PLKF and VC–PLKF outperform the BC–PLKF and IV–PLKF both in non-manoeuvring and manoeuvring scenarios.

Surface microtexturing has been widely used due to its good hydrophobic or drag reduction characteristics, and become an effective method to improve product performance and reduce energy consumption. This paper mainly discusses the improvement of microtextures on the dynamic pressure characteristics of hydrostatic bearings, and explores the effects of texture parameters on carrying capacity, macroscopic wall two-plane shear force, cavity area and other factors. In the oil film model calculation of the smooth wall surface of the radial hydrostatic bearing under the action of high speed and large external load, the oil film divergent wedge often has a negative pressure area, which is obviously not in line with the actual situation, so the cavitation effect needs to be considered. The CFD analysis method of the “gas-oil” two-phase flow model was carried out by using the mixture model to seek the optimal texture model scheme and thus to improve the load carrying capacity (LCC) and reduce the wall shear force. The effects of the texture area arrangement and geometric parameters on the lubrication characteristics were compared and analyzed. It is found that the carrying capacity of local texture is better than that of global texture, and different texture arrangements can achieve better drag reduction rates. The work presented in this paper studies the lubrication of the surface texture of a hydrostatic bearing. Taking the oil film carrying capacity and shear force as the target parameters, the factors, such as texture morphology, geometric parameters, texture distribution and cavitation phenomenon, are investigated through simulation and experimental methods. The surface textured hydrostatic bearing is expected to obtain the maximum oil film carrying capacity and the minimum friction resistance. The analysis results show that by arranging the partial streamwise texture at the rear end of the diverging wedge, the maximum shear force of the wall can be reduced by about 15%, and the LCC can be increased by about 18%.

Plant polysaccharides, a type of important bioactive compound, are involved in multiple plant defense mechanisms, and in particular polysaccharide-alleviated abiotic stress has been well studied. Polygonatum cyrtonema Hua ( P. cyrtonema Hua) is a medicinal and edible perennial plant that is used in traditional Chinese medicine and is rich in polysaccharides. Previous studies suggested that sucrose might act as a precursor for polysaccharide biosynthesis. However, the role of sucrose metabolism and transport in mediating polysaccharide biosynthesis remains largely unknown in P. cyrtonema Hua. In this study, we investigated the contents of polysaccharides, sucrose, glucose, and fructose in the rhizome, stem, leaf, and flower tissues of P. cyrtonema Hua, and systemically identified the genes associated with the sucrose metabolism and transport and polysaccharide biosynthesis pathways. Our results showed that polysaccharides were mainly accumulated in rhizomes, leaves, and flowers. Besides, there was a positive correlation between sucrose and polysaccharide content, and a negative correlation between glucose and polysaccharide content in rhizome, stem, leaf, and flower tissues. Then, the transcriptomic analyses of different tissues were performed, and differentially expressed genes related to sucrose metabolism and transport, polysaccharide biosynthesis, and transcription factors were identified. The analyses of the gene expression patterns provided novel regulatory networks for the molecular basis of high accumulation of polysaccharides, especially in the rhizome tissue. Furthermore, our findings explored that polysaccharide accumulation was highly correlated with the expression levels of SUS , INV , SWEET , and PLST , which are mediated by bHLH , bZIP , ERF , ARF , C2H2 , and other genes in different tissues of P. cyrtonema Hua. Herein, this study contributes to a comprehensive understanding of the transcriptional regulation of polysaccharide accumulation and provides information regarding valuable genes involved in the tolerance to abiotic stresses in P. cyrtonema Hua.

As the construction of photovoltaic power plants continues to expand, investors have placed great importance on the suitability assessment of site selection. In this study, we have developed a multi-level evaluation system and proposed an AHP–XGBoost–GIS comprehensive evaluation model for assessing site suitability in the Beijing–Tianjin–Hebei region. The findings revealed that approximately 48,800 km2 (21.59% of the total area) constituted a suitable area in this region, surpassing previous research results. Generally suitable areas accounted for the largest proportion at 35.89%. Suitable areas in Beijing and Tianjin were relatively limited, with most of them concentrated in Baoding City, Zhangjiakou City, and Chengde City on the northwest side of the “Yanshan-Taihang Mountains”, where there are ample wastelands with gentle slopes conducive to constructing photovoltaic power plants southeast of the “Yanshan-Taihang Mountains”, and solar radiation conditions were better. However, ecological and economic factors restricted suitable areas resulting in smaller coverage including cities such as Handan, Xingtai, Qinhuangdao, and Tangshan, among others. This study successfully overcame limitations associated with traditional subjective evaluation methods by providing decision support for regional energy allocation planning and spatial planning efforts, as well as environmental protection endeavors.

Hydrostatic bearing spindles are widely applied in high precision grinding and turning machines due to their good dynamic stability and rotational accuracy. However, under the condition of high-speed rotations, the heat generated by the friction of the oil film will cause the shear thinning effect. It not only reduces the rotation accuracy of the spindle but also reduces the service life of the spindle. The surface texture structure and configuration between the planes play the role of homogenizing oil film temperature and preventing the bearing surface wear caused by excessive concentration of temperature, which can change the relative motion from the inside of the oil film and thus improve the performance of the hydrostatic spindle more effectively. In this paper, the influence of the surface texture shape and height on the thrust bearing performance of the hydrostatic spindle is systematically investigated by comparative analysis. The CFD simulations are developed to analyze the computational results based on the theory of viscosity-temperature characteristics. The results show that when the height of the surface structure is 1 ~ 2 times the oil film thickness, the spindle bearing performance is the best. The average temperature in the bearing region is the lowest and the accuracy of the simulations was verified by experimental results.

Bearings are critical components in mechanical systems, and their degradation process typically exhibits distinct stages, making stage-based remaining useful life (RUL) prediction highly valuable. This paper presents a model that combines correlation analysis feature extraction with a Graph Neural Network (GNN)-based approach for bearing degradation stage classification and RUL prediction, aiming to achieve accurate bearing life prediction. First, the proposed Pearson–Spearman correlation metric, along with Kernel Principal Component Analysis (KPCA) and autoencoders, is used to group and fuse health indicators (HIs), thereby obtaining a health indicator (HI) that effectively reflects the bearing degradation process. Then, a model combining Graph Convolutional Network (GCN) and Long Short-Term Memory (LSTM) networks is proposed for bearing degradation stage classification. Based on the classification results, the Adaptive Attention GraphSAGE–LSTM (AAGL) model, also introduced in this study, is employed to precisely predict the bearing’s remaining useful life.

Transmission towers are continuously exposed to corrosive environments, and corrosion of their structural members can significantly reduce the overall load-carrying capacity and stability. In this study, four locally corroded angle steel specimens with single-side connections were fabricated using an electrochemical method. Eccentric compression tests were conducted on these four corroded specimens together with two uncorroded reference specimens. The failure modes, load–displacement curves, and load–strain responses of the corroded specimens were systematically analyzed. It was observed that the strain in the compression leg exceeded that in the free leg. A finite element model, validated against experimental results, was employed for a parametric study to investigate the effects of the spacing between two corrosion regions, their respective relative corrosion depths, and corrosion areas on the degradation rate of load-carrying capacity. Based on the observed influence patterns of these corrosion parameters, an assessment method for capacity degradation under a “dual corrosion region” configuration was developed, accounting for three scenarios: corrosion on the compression leg, the free leg, or both sides simultaneously. This method comprehensively captures realistic corrosion characteristics and demonstrates improved rationality and accuracy. Finally, a sensitivity analysis was performed using the proposed assessment approach, examining key parameters including section corrosion ratio, corrosion area, corrosion location, and slenderness ratio. The results indicate that, under the dual corrosion region condition, the section corrosion ratio is the most dominant factor influencing the capacity degradation rate.

Hydrostatic thrust bearings are the core part of the hydrostatic spindle, which is widely used in high precision grinding machines. In this paper, the viscosity-temperature (v-t) characteristics of hydrostatic oil are systematically investigated, which is essential for improving the performance of the hydrostatic thrust bearing and the spindle working at high pressure and high rotational speed. Based on the computational fluid dynamics (CFD) simulation developed, the performance variation rules of thrust bearing surface are established while changing the oil supply pressure. It is found that the bearing capacity and temperature are obviously affected by varying viscosity-temperature characteristics, which have significant fluctuation phenomenon at the orifice. Furthermore, the turbulence intensity of the taper hole is found the least factor by analyzing four kinds of commonly used orifice type configurations. Finally, comparing the simulation and experimental results, the v-t model developed is proofed well matching with the experiment. The model can provide a basis for accurate design and analysis of hydrostatic thrust bearings and consequently the effective design and analysis of the hydrostatic spindle for high precision grinding machine.

Background Previous studies found that Polygonatum sibiricum polysaccharide (PSP) exhibited anti-inflammatory and anti-oxidative effects on type 2 diabetes (T2DM). However, the roles and detailed mechanisms of PSP on the anti-diabetic osteoporosis are still poorly defined. The purpose of this study was to identify the detailed mechanisms of PSP-induced anti-diabetic osteoporosis. Methods The roles of PSP on diabetic osteoporosis were evaluated on a T2DM zebrafish model. Furthermore, the changes of related physiological indicators and metabolites in adult zebrafish (Danio rerio) were investigated by pharmacology and metabolomic analyses. Results Results showed that PSP significantly reduced the blood glucose content and induced caudal fin regeneration. Metabolomic analysis found that the key metabolites involved in arachidonic acid metabolism, PPAR signaling pathway, linoleic acid metabolism, steroid hormone biosynthesis, amino acid biosynthesis and metabolism, alpha-Linolenic acid metabolism, sphingolipid signaling pathway were affected by PSP treatment. Among these, PSP reversed the trend changes of several metabolites, such as L-aspartic acid, choline, and propionylcarnitine. Besides, further changes of TNF-α and IL-1β transcripts suggested that the proinflammatory cytokines were also involved in the PSP-triggered anti-diabetic osteoporosis. Conclusion Above findings provided the theoretical basis for the use to plant PSP as food ingredients or bioactive compounds in natural health products on diabetic osteoporosis.

The dynamic performance and life of the precise bearing, even abnormal operation and early failure are affected directly by the complex and unstable motion of the cage. Based on the cage dynamic performance test device with controllable motion of inner and outer rings, respectively, the dynamic characteristics of the cage were studied under different rotating speeds and loads, while inner ring rotated with outer ring fixed and inner–outer rings rotated reversely. Then the trajectory of the cage mass center was drawn through experimental study. The three-dimensional space motions of cage reveal that, when only inner ring rotates, the trajectories of cage mass center are approximately circular under axial load, and the amplitude of the axial displacement raises with the increase of the rotation speeds. With the increase of radial loads, the cage mass center trajectories are shaking from a circle to a small area on the side of the bearing center. When the inner–outer rings rotate in the opposite direction, the rotation speed of the cage is greatly reduced, and the mass center trajectories of the cage oscillate irregularly on side of the bearing center. As the relative rotation speed of rings increases, the axial displacement fluctuation enlarges. With the increase of the radial loads, the axial fluctuation decreases.