Continuum robots have been widely used in natural cavity intervention therapy, but the current flexible continuum robots have poor positioning accuracy and lack of accurate navigation means. In response, a multi-segment continuum robot shape reconstruction method based on electromagnetic positioning information was proposed, aimed at achieving accurate end navigation and positioning. An efficient two-stage active structure shape reconstruction method based on third-order Bessel curve was proposed. The solution of Bessel curve was optimized to nonlinear least squares problem, which was solved quickly and accurately by particle swarm algorithm with linear decreasing weights. The proposed method can accurately fit the shape of the two-segment continuum and has good real-time performance. The results show that within the bending angle process, the average root-mean-square error of shape reconstruction is 0.48 mm, which is 0.8% of the length of the continuum bending segment. The accuracy and reliability of the proposed shape reconstruction method for intracavitary interventions using micro-continuum robots are demonstrated through detailed modeling and validation results.

In order to investigate the properties of seawater mixing alkali-activated materials, the development law of hydration reaction, mechanics and corrosion resistance of seawater alkali-activated materials based on multi-component composite cementitious materials was studied. The results show that seawater mixing has a certain inhibitory effect on the hydration reaction of alkali-activated slag, and the compressive strength of SLCM at different ages also shows a decreasing trend to a certain extent, which is not conducive to the development of strength. Fly ash and silica fume can reduce the hydration reaction rate, early strength and toughness of the seawater alkali-activated materials, but their strength and toughness increase potential is significant in the later period, in which the strength and toughness growth rate of the silica-fly ash-slag terpolymer system from 7 days to 28 days reaches 50.9% and 86.7%, respectively. Compared with alkali-activated slag, adding fly ash and silica fume can improve the electric flux permeability and chloride ion mobility coefficient of alkali excited materials in seawater to a certain extent, which is consistent with their microstructure, but the three still belong to the same chloride ion permeability grade, i.e., medium permeability grade (electric flux method).

During growth, crop stalks are prone to bending deformation, posing challenges for computer visualization simulation. A differential analysis method was employed to investigate the physical stress-strain relationship of stalks, and a visualization simulation method was proposed for flexible stalks. Firstly, a mechanical model of the stalk under tensile, bending, shear, and torsional loads was established. Secondly, a geometric model based on a semi-structural approach and surface modeling was constructed. Finally, C++ and OpenGL were utilized to implement the visualization simulation. Experimental analysis of the bending stress-strain characteristics of stalks from different varieties was conducted. The results demonstrate that this method can relatively accurately simulate the deformation process of stalks. The physics-based model ensures the accuracy of bending simulation, providing a novel informatics analysis tool for selecting and breeding lodging-resistant crop varieties.

In order to accurately predict the water richness of the weathered bedrock aquifer, 28 groups of weathered bedrock pumping test borehole data in Zhangjimao minefield were used as training and verification samples, and the lithology combination index, weathering index, thickness, core recovery rate and burial depth of the weathered bedrock were selected as evaluation indexes. Based on whale optimization algorithm-support vector machines (WOA-SVM), a water-rich identification model for weathering bedrock aquifers was proposed. This model can predict the water-rich grade of the weathered bedrock in the area without pumping test data, and realize water-rich zoning of the weathered bedrock in the well field by comprehensive use of the geological information of 249 exploration boreholes. The study shows that the weathered bedrock of Zhangjiamao minefield is weakly water-rich as a whole, and its spatial distribution is uneven. There are strong water-rich areas in the central part of the field and the local area along Wulanbula Gully, but their distribution range is small, there are some moderately water-rich areas in the central-western and southeastern parts, and the northeastern and southwestern areas are weakly and very weakly water-rich almost all the time. The results predicted are more in line with the actual situation, and the research results can provide a reference for the safe production of the mine and a new way of thinking for the prediction of the water-richness of the weathered bedrock.

The effect of water flooding development in low permeability reservoir is generally poor, and CO₂ flooding can effectively improve the degree of crude oil recovery. In order to analyze various factors affecting the effect of CO₂-assisted gravity flooding, based on the research mechanism of gas-injection-assisted gravity flooding, a mechanism model of one injection and one production was established to analyze the influence law of geological factors and development factors, and the orthogonal experimental design method and Shapley value method were used for multi-factor analysis. The results show that the positive rhythm reservoir is more suitable for CO₂-assisted gravity flooding. Reservoir dip angle, average permeability and gas injection velocity are positively correlated with development effect. The ratio of vertical permeability to horizontal permeability and the difference of permeability stage were negatively correlated with the development effect. If the ratio of gas injection and dimensionless horizontal well section length is set to 0.8, the CO₂-assisted gravity flooding effect can be effectively improved. The ratio of vertical permeability to horizontal permeability has the highest influence on CO₂-assisted gravity flooding. The research results provide technical guidance and theoretical support for improving the development effect of CO₂-assisted gravity flooding in low permeability reservoirs.

Aiming at the problem of effective extraction and identification of rolling bearing fault information in complex environments, a fault diagnosis method for rolling bearings based on feature mode decomposition (FMD) combined with multiscale fuzzy dispersion entropy (MFDE) and zebra optimization algorithm (ZOA) optimization support vector machine was proposed. In order to solve the problem that the key parameters in FMD are not adaptive, the minimum envelope entropy was used as the objective function, and the beluga whale optimization (BWO) was used to optimize FMD to find the optimal parameter combination to achieve the optimal decomposition of fault signals. Multiscale fuzzy dispersion entropy was introduced to construct the eigenvectors under different modes after decomposition. Finally, the feature vectors were input into the support vector machine for training and recognition. The effectiveness of the proposed method was verified by the public dataset and the self-made experimental platform dataset.

The drilling process requires real-time measurement of drill string vibration, which is crucial for drilling and downhole safety. However, the traditional power supply mode used for downhole vibration sensors has been found to increase drilling costs and reduce drilling efficiency. Therefore, sensors with self-powered capabilities are considered more suitable for practical conditions. A downhole arrayed self-powered deformable vibration sensor was proposed based on the principle of triboelectric nanogenerators. Experimental results demonstrate that the sensor synchronized measurements of amplitude and frequency. The vibration frequency is measured within a range of 0 Hz to 11 Hz, with a measurement error of less than ±4%. Additionally, the sensor is able to measure three discrete amplitude values (10, 25, 40 mm) with a measurement error of ±3 mm. The sensor can working normally within a temperature range of 0 ℃ to 85 ℃. Furthermore, the sensor has power generation capabilities, with experiments revealing a maximum output power of 8.3×10^-7 W. Notably, when multiple sensors are used in parallel, the power generation capacity is significantly enhanced. These research findings provide new insights for the development of downhole sensors and downhole generators.

Aiming at the problem of short effective prediction time for the movement history of amphibious aircraft in waves, the statistical values of amphibious aircraft movement over a period of time were proposed to predict, and a prediction model for the statistical characteristics of amphibious aircraft movement was constructed based on long short-term memory neural networks(LSTM). Taking the NACA TN 2929 amphibious aircraft as an example, based on its numerical simulation data, the statistical values of the three degrees of freedom motion of heave, roll, and pitch of amphibious aircraft under sea conditions of level 3, 4, and 5 were predicted, and their prediction effects were analyzed in detail. The results show that the LSTM neural network-based model for predicting the statistical characteristics of amphibious aircraft motion has good prediction accuracy. In practical engineering applications, this model can accurately predict the statistical values of amphibious aircraft motion in the future, providing auxiliary decision-making information for offshore operations.