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Considering the uncertainty associated with structural boundary conditions, a method for modifying the boundary constraint static model of beam structures was proposed based on the homotopy stochastic finite element method. The overall modification of both the beam body elements and boundary elements was achieved using uncertain static measurement data. By employing the static condensation method, computational degrees of freedom were ensured to match measured degrees of freedom. Regularization methods were applied to mitigate ill-conditioned solutions in modification equations for stochastic models. The probabilistic residual minimization method enables optimal selection of homotopy coefficients, ensured accurate identification of boundary constraints and precise overall modification. Finally, simulations on variable-section concrete beams and static loading tests on aluminum alloy beams were conducted to verify the effectiveness of this approach.

Objective To explore the causal relationship between ischemic stroke and different types of epilepsy so as to provide genetic evidence for the risk of epilepsy after ischemic stroke. Methods Based on the summary data of genome-wide association study, Mendelian randomization (MR) analysis was performed with MR-Egger regression, weighted median and inverse-variance weighting. Sensitivity analysis was conducted by using MR-Egger regression test, MR-PRESSO test and leave-one-out method. Results Two-sample MR analysis showed that there was a causal relationship between ischemic stroke and the risk of epilepsy (OR=1.10, P=0.036) and generalized epilepsy (OR=1.25, P=0.001), but no such relationship was observed with the risk of focal epilepsy (OR=1.06, P=0.360). In addition, diastolic blood pressure (OR=1.12, P=0.002) and BMI (OR=1.08, P=0.015) also had a causal relationship with the risk of epilepsy. After adjusting confounding factors, multivariate MR analysis revealed that only ischemic stroke (OR=1.18, P=3.770×10-6) and epilepsy risk had a causal relationship. Conclusion There is a causal relationship between ischemic stroke and the risk of generalized epilepsy, which can be used to stratify the risk of post-stroke epilepsy.

[Objective] This study aimed to investigate the correlation between taste substances and flavor presentation intensity of Shuixian Wuyi rock tea from different storage years. [Methods] The main taste substances, including tea polyphenols, flavonoids, free amino acids, soluble sugars, catechins and other components, were detected in several years of Narcissus (2022, 2018, 2016, 2014, 2012, 2010, 2008, 2006 for storage 1, 3, 5, 7, 9, 11, 13, 15 years, respectively) by using chemical methods and high-performance liquid chromatography, and the reasons for the change of the two and their correlation were analyzed by combining with the sensory evaluation of the electronic tongue. [Results] With the increase of storage year, the contents of tea polyphenols, soluble sugars, and catechins in Narcissus showed a decreasing trend, the total flavonoids and free amino acids showed an inconspicuous trend, and the contents of caffeine, gallic acid, and theaflavin increased in general. Its freshness showed an increasing trend, richness, bitterness, astringency, and its aftertaste showed a decreasing trend, while the salty and sweet tastes fluctuated up and down within a certain level. [Conclusion] EGCG of Shuixian in different years showed a strong positive correlation with a bitter taste, astringent aftertaste, and richness, while EGC showed a strong negative correlation with sourness, TF, and astringency.

With rapid urbanization and the structural transformation of economic development, cultivated land abandonment is becoming more serious, posing great threats and challenges to the security of food production. The rapid and accurate monitoring of cultivated land abandonment is of great value for ensuring regional and national food security. In view of the urgent need for abandoned land monitoring, we proposed a method to identify abandoned land based on the temporal features of optical time series data. First, the NDVI time series of cultivated lands was constructed using multitemporal Sentinel-2 data. The constructed NDVI time series was preprocessed to filter out outliers among the observations. Subsequently, the amplitude feature of the NDVI time series was extracted for cultivated land. We acquired the amplitudes of the abandoned and non-abandoned land samples and generated statistics for the range of amplitudes. We then extracted the optimal threshold of NDVI amplitude for separating abandoned land from non-abandoned land using two steps: initialization and optimization of the threshold. In the initialization step, the maximum NDVI amplitude among the abandoned land samples was set as the initial threshold. In the optimization step, the threshold was decreased in step of 0.01, and the F1-score was calculated iteratively to determine the optimal threshold. With a decrease in the threshold when the F1-score reached its highest value, the corresponding threshold was set as the optimal threshold. Accordingly, the rule for abandoned land recognition was constructed; namely, when the NDVI amplitude was lower than the optimal threshold, cultivated land was classified as abandoned land. Finally, based on the mapping results, landscape pattern indices were calculated to analyze the landscape pattern characteristics of abandoned lands. The proposed method was validated in Potou District, Zhanjiang City, Guangdong Province, China. The main results of the study were as follows: 1) Comparing the NDVI time series curves of abandoned and non-abandoned lands, we found that the NDVI time series curves of abandoned land changed gently, whereas the NDVI time series of non-abandoned land changed with great fluctuation due to the phenological process of crop growth. 2) By iteratively searching for the optimal NDVI amplitude, the optimal segmentation threshold of NDVI amplitude was 0.42 for distinguishing abandoned lands from non-abandoned lands in Potou. We used 100 abandoned and non-abandoned land samples to validate their accuracy. By using this optimal threshold, the overall recognition accuracy of abandoned land reached 91.83%, and the overall extraction accuracy of non-abandoned land reached 90.20%. 3) The calculation results of the landscape pattern index of abandoned lands revealed that these are generally small and have irregular shapes. Abandoned lands were scattered throughout Potou. This study demonstrates that the proposed method can effectively identify abandoned land using the amplitude of NDVI time series. This method can produce highly reliable abandoned land mapping and shows good potential for large-scale agricultural applications.

The traditional fatigue life prediction method Miner theory ignored the damage caused by stress below the fatigue limit to the component, resulting in a large error in fatigue life prediction. In order to calculate the damage caused by the stress below the fatigue limit to the component, according to the loading stress and its characteristics of the damage, the partial large membership function in the semi-trapezoidal and trapezoidal distribution is selected, and the degree of damage caused by the stress below the fatigue limit is characterized by its membership. The damage phenomenon reflected by this membership functionis regarded as a gray system, and an equally spaced GM(1,1) model of stress and membership is established. Then, it fitted its function expression and combined it with the membership function to calculate the damage caused by stress below the fatigue limit. Two sets of 41Cr4 multi-level loading experimental data were used to verify and evaluate the proposed new model, and the error between the estimated results and the experimental results was about 7.5%. Compared with Miner theory, the predicted fatigue life model of the equally spaced grey system, and the grey Verhulst predicted fatigue life model, this model improves the fatigue life prediction accuracy.

The distribution of surface water is highly dynamic both spatially and temporally, and very sensitive to climate change and anthropogenic interference, especially in highly urbanized regions. The abundance of surface water and its spatiotemporal distribution indicate the availability of water resources and the difficulty of water development and utilization. Consequently, it is essential to perform reconstruction and trend prediction of surface water body changes with high accuracy in time and space for scientific research as well as for practical purposes such as flood prevention, sustainable development of water resource systems, and regional ecological management. The Guangdong-Hong Kong-Macao Greater Bay Area (GBA) is highly developed economically and societally and is characterized by a subtropical humid monsoon climate with an extensive distribution of surface water bodies. Under the integrated pressure of continuous natural environmental change and intense human activity, concerns regarding both the water environment and water security in this area is increasing at an unprecedented rate. In this study, we collected water distribution information from 2001 to 2020 at 5-year intervals, as well as annual and monthly water extent dynamics data for the GBA from the Global Land Analysis & Discovery database. Subsequently, the spatial and temporal changes in water extent, frequency, and distribution characteristics in the last two decades were investigated using remote sensing and geographic information system methods. Finally, elastic analysis was conducted to identify the sensitivity of water body changes to changing environmental parameters, including precipitation, temperature, and urbanization. Focusing on the national and regional strategic needs of GBA, the research objectives of this study were to explore the mechanism of temporal and spatial dynamics of the water extent and frequency, trace the volatile areas of regional water changes, clarify the driving factors of water distribution changes, and provide a basis and guidance for comprehensive management of water resources, flood disaster prevention, and control in areas with high human activity. The first result shows that in the last two decades, the water extent and frequency of the GBA are on a decreasing trend, with an average decreasing rate of 50, 31, and 11 km2/a for maximum, annual, and permanent water extent, respectively, while a large proportion of seasonal water bodies changed into permanent and flood-prone bodies during the same period. Second, although the water frequency showed distinct spatial and urban/rural heterogeneity, it was on a decreasing trend in most of the GBA, except in the eastern region. A steeper decline was observed in urban areas, especially the emerging urban regions. Third, the dike-pond system decreased both in water extent and frequency, while the large and medium-sized lakes and reservoirs in the upper catchment increased in extent. Finally, elastic analysis suggests the dominant driving factor of regional water body change is land use change, which contributed more than 80% to the decrease in water extent, and the reservoir increase is mainly due to precipitation change. The results of this research provide scientific guidance for regional water resource guarantee, water environment optimization, and sustainable development promotion. In addition, this research can serve as a decision-making reference for the development of the "One Belt One Road" national strategy and Guangdong-Hong Kong-Macao Greater Bay Area.

In view of problem that drill pipe transportation depends on manual operation in vane welding process of spiral drill pipe, travelling bogie was applied to vane welding station of spiral drill pipe, which realized transportation of drill pipes between loading and unloading stations and two welding stations. Control program of the travelling bogie was programmed by PLC-FX3U to achieve joint coordination between the travelling bogie and welding station. Application results show that transport time of the entire drill pipe transport process was shortened by nearly half and the efficiency was increased by about 43% after use of the travelling bogie.