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The P-S-N curve of high and low cycle fatigue for aero-engine materials are essential to evaluate the service life of rotor components. However， it requires extensive experimental time and high material cost. Based on the physical-informed machine learning （PIML） method， a novel optimization method was proposed for combined high and low-cycle fatigue P-S-N curves with a small size sample， in which the equivalent principle of fatigue life and the consistency criteria of life distributions were introduced into the extreme learning machine（ELM） through its loss function. In addition， bi-level optimization was employed with the upper level of model input variables and the lower level of the ELM model parameters. Subsequently， the proposed PIML method was compared with a data-driven machine learning method and traditional P-S-N curve fitting methods through the fatigue test data.The results show that the method not only effectively solves the problem of nonlinearity between the stress level and the standard deviation of fatigue life， but also presents the highest accuracy of the predicted probabilistic lives.

The spatial form of the rural ecological landscape and the vulnerability of the water ecological environment are evaluated to understand the status of the rural ecological system and provide a scientific basis for improving and protecting the rural ecological environment. With the acceleration of the urbanization process, rural areas in urban fringe areas have become an important carrier of urban space expansion and function allocation due to their advantages in transportation and resources, and have been included in the urban production and consumption system. The fast change in country capabilities and the consistent change in land use structure show a differentiated and enthusiastic improvement pattern. According to the point of view of provincial rejuvenation and new urbanization, this study discussed about the time-space qualities of provincial change and land use change, examined the coupling connection between rustic change and land use change, and set forward commonsense country improvement procedures and land guideline measures, which can not only stimulate the vitality of rural development but also consolidate the foundation of rural revitalization. Through the investigation and analysis of rural ecological land, it was found that the rural ecological land decreased from 95.14 to 89.84% from 2015 to 2019, then rose to 92.94%, and finally fell back to 91.74%, which is relatively stable on the whole. It can be seen that the spatial form, coupling, and coordination of the water ecological environment in rural ecological landscape presents a stable trend.

Spark plasma sintering (SPS) is an ultrafast sintering method for the preparation of ceramics and ceramic composites with simple geometrical shapes, with the combined application of uniaxial pressure. This study aims to propose an SPS densification method for Si3N4 ceramic balls without necessitating alterations to tools and equipment. The Si3N4 ceramic balls intended for sintering are positioned within a SiC powder bed inside the conventional die used in SPS. The study systematically investigates the effects of presintering temperature (1400°C, 1500°C, and 1600°C) and SPS temperature (1600°C, 1700°C, and 1800°C) on the sphericity, relative density, phase composition, microstructure, and mechanical properties of Si3N4 ceramic balls. Experimental findings reveal that Si3N4 ceramic balls exhibiting an optimal combination of sphericity (0.94 ± 0.02), relative density (98.4%), and mechanical properties (Vickers hardness: 17.5 ± 0.4 GPa, fracture toughness: 6.4 ± 0.1 MPa·m1/2) were successfully achieved at a pre‐sintering temperature and SPS temperature of 1600°C, coupled with the use of a SiC powder bed and SPS method. Consequently, the SPS method demonstrates its capability to fabricate Si3N4 ceramic balls with excellent performance. [ABSTRACT FROM AUTHOR]

Abstract Background Understanding the genetic mechanisms of local adaptation is an important emerging topic in molecular ecology and evolutionary biology. Results Here, we identify the physiological changes and differential expression of genes among different weeping forsythia populations under drought stress in common garden experiments. Physiological results showed that HBWZ might have higher drought tolerance among four populations. RNA-seq results showed that significant differential expression in the genes responding to the synthesis of flavonoids, aromatic substances, aromatic amino acids, oxidation–reduction process, and transmembrane transport occured among four populations. By further reanalysis of results of previous studies, sequence differentiation was found in the genes related to the synthesis of aromatic substances among different weeping forsythia populations. Conclusions Overall, our study supports the hypothesis that the dual differentiation in gene efficiency and expression increases among populations in response to heterogeneous environments and is an important evolutionary process of local adaptation. Here, we proposed a new working model of local adaptation of weeping forsythia populations under different intensities of drought stress, which provides new insights for understanding the genetic mechanisms of local adaptation for non-model species.