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The caisson method is typically employed in foundation pit projects characterized by complex surrounding structures and challenging engineering geological conditions. The sinking process involves complex soil-structure interactions, particularly the sidewall friction between the caisson and the surrounding soil strata. This friction is a critical factor, as it not only determines the feasibility and safety of the sinking operation but also influences the pattern and magnitude of surrounding ground subsidence. This study aims to explore the mechanism of sidewall friction between the caisson and strata and its direct impact on controlling the sinking process and mitigating surrounding subsidence. The analysis is based on the large caisson engineering of Zhuchong Pump Station, located in Xinyang City behind the Chushandian reservoir. By conducting a numerical simulation of the sinking process and analyzing measured data from on-site subsidence monitoring points, this research reveals that the caisson induces a parabolic-shaped subsidence curve in the surrounding ground surface. The magnitude and extent of ground subsidence around the caisson increase with greater sinking depth and with proximity decreasing distance from the sidewall. The study further demonstrates that sidewall friction significantly influences ground subsidence. Specifically, lower friction in the initial sinking phase results in noticeable ground uplift due to reduced constraint on soil displacement. Conversely, higher friction leads to increased ground subsidence as the sinking depth progresses. The study reveals that the influence pattern of friction between the caisson sidewall and the surrounding soil on ground surface subsidence, and lower friction would result in pronounced ground uplift due to reduced constraint on surface displacement during the initial sinking phase, and higher friction would increase ground subsidence as the caisson sinking depth increases. The findings of this research may help provide a technical reference for subsidence control in similar large-scale caisson projects.

The swarm planar underactuated robots have the ability to organize each robot to complete task in a finite time and the characteristics of ignoring gravity, energy saving, light weight, and so on. In this paper, we propose control strategy for such robot via motion planning and intelligent algorithm. First, we establish a unified dynamic model and analysis its underactuated characteristics. In order to enable all links to reach the target position smoothly in a finite time, a suitable trajectory is planned and parameters are optimized by the differential evolution algorithm (DEA). Then, the controllers are designed for each planar underactuated robot. Finally, the simulation results show that the proposed strategy is effective.

Lakes, as key freshwater reserves and ecosystem cores, supply human water, regulate climate, sustain biodiversity, and are vital for global ecological balance and human sustainability. Lake Chaohu, as a crucial ecological barrier in the middle and lower reaches of the Yangtze River, faces significant environmental challenges to regional sustainable development due to water quality deterioration and consequent eutrophication issues. To address the limitations of conventional monitoring techniques, including insufficient spatiotemporal coverage and high operational costs in lake water quality assessment, this study proposes an enhanced Informer model optimized by the Whale Optimization Algorithm (WOA) for predictive analysis of concentration trends of key water quality parameters—dissolved oxygen (DO), permanganate index (CODMn), total phosphorus (TP), and total nitrogen (TN)—across multiple time horizons (4 h, 12 h, 24 h, 48 h, and 72 h). The results demonstrate that the WOA-optimized Informer model (WOA-Informer) significantly improves long-term water quality prediction performance. Comparative evaluation shows that the WOA-Informer model achieves average reductions of 9.45%, 8.76%, 7.79%, 8.54%, and 11.80% in RMSE metrics for 4 h, 12 h, 24 h, 48 h, and 72 h prediction windows, respectively, along with average improvements of 3.80%, 5.99%, 11.23%, 17.37%, and 23.26% in R2 values. The performance advantages become increasingly pronounced with extended prediction durations, conclusively validating the model’s superior capability in mitigating error accumulation effects and enhancing long-term prediction stability. Spatial visualization through Kriging interpolation confirms strong consistency between predicted and measured values for all parameters (DO, CODMn, TP, and TN) across all time horizons, both in concentration levels and spatial distribution patterns, thereby verifying the accuracy and reliability of the WOA-Informer model. This study successfully enhances water quality prediction precision through model optimization, providing robust technical support for water environment management and decision-making processes.

Underactuated system control is a central topic in nonlinear system control. For the three-link vertical underactuated manipulator with only the first joint actuated (APP manipulator), the control objective of swing-up and balancing is challenging. The advantages of this paper are as follows: (i) The proposed method avoids balancing region division in common partitioned control, preventing failure to stabilize at the target position due to improper partitioning. (ii) The time-based switching condition optimized via parameter tuning is easier to satisfy than the state-based condition. (iii) The proposed controller effectively suppresses state fluctuations caused by switching, yielding a smoother transition. (iv) The proposed controller avoids the singularity problem. The main procedures are as follows. First, the dynamic model of the APP manipulator is established. Then, a trajectory is designed to guide the active link from the initial position to the vicinity of the target position. On this basis, to ensure that all links can simultaneously reach the vicinity of the target position, the trajectory parameters are optimized according to the coupling relationship between the links. Next, an NFTSM-based tracking controller is developed to steer the links along the optimized trajectory. After that, an LQR-based stabilization controller is further employed to lock the system at the target position. Finally, the effectiveness of the proposed method is verified through simulations.

Electrospinning is a highly efficient mild method to obtain stereocomplex poly(lactic acid) fibers from blends of high molecular weight (MW) poly(L-lactic acid) (PLLA) and poly(D-lactic acid) (PDLA). However, high MW PLAs are expensive and proved difficult to avoid homocrystallites which weaken the performances. Here, di-stereoblock poly(lactic acid)s (di-sb-PLAs) with low MW of 104 g mol−1 were synthesized and electrospun into membranes. The stereocomplex (sc) crystallites were induced by sintering the amorphous as-spun membranes at 200 °C, and further improved by applying 1 MPa pressure which promoted the segment migration across fiber intersections and welded the fibers by forming new sc crystallites. Due to more readily crystallize at molecular level than the blend of PLLA and PDLA, the sintered di-sb-PLA membranes exhibited higher thermal stability, better tensile strength, and were more stable during multiple cycles of selective separating solvent and water mixtures. Increasing MW of di-sb-PLA positively affected the membrane properties and inhibited dramatical embrittlement that occurred in sintered membrane of PLLA and PDLA blend.

For the planar robot with underactuated constraints, a stable control method is presented on the foundation of motion planning method and intelligent optimization, which includes two stages. (1) Designing the controllers to control the actuated manipulators to given target states. (2) Planning the motion trajectory combined with the underactuated constraints between all links, using the intelligent algorithm to find the adaptable trajectory parameters, and tracking such planned trajectories to control full manipulators to the given states simultaneously. At last, multigroup simulations demonstrate the validity of the proposed method.

To explore the neuromuscular control mechanism and quantifying the fatigue response during bench press exercise is important references to prescribe an appropriate exercise program. However, current literature struggles to provide a concrete conclusion on the changes of intermuscular EMG-EMG coupling between synergistic and antagonist muscles during the exercise. Thus, the current study was designed to reveal fatigue-related changes of intermuscular EMG-EMG coupling during bench press exercise. Thirty-one healthy male participants performed a bench press exercise on the Smith machine at 60% One Repetition Maximum (1RM) workload to exhaustion, while surface electromyographic signals (sEMG) were collected from triceps brachii (TB), biceps brachii (BB), anterior deltoid (AD), posterior deltoid (PD), and pectoralis major (PM). Surface EMG signals were divided into the first half and second half of the bench press exercise. Phase synchronization index (PSI) was calculated between sEMG of synergistic muscle pairs AD-TB, AD-PM and antagonist muscle pairs BB-TB, AD-PD. EMG power of TB, AD, PD, PM muscles in alpha (8-12 Hz) frequency band and EMG power of each muscle in beta (15-35 Hz), and gamma (35-60 Hz) frequency bands were all increased during the second half of contraction compared with the first half of contraction. PSI of gamma frequency band was significantly decreased in BB-TB muscle pair while EMG-EMG coupling of AD-TB in gamma frequency band was significantly increased during the second half of contraction compared to the first half of contraction. The results indicated a decrease of interconnection between synchronized cortical neurons and the motoneuron pool of BB and TB, and an increase of interconnection between AD-TB muscles during fatiguing bench press exercise at 60% 1RM workload. The changes of intermuscular coupling may be related to the supraspinal modulations to compensate for the decrease of muscle force as well as a result of unbalanced changes of agonist and antagonist muscle contractility.

Background The Five Times Sit-to-Stand Test (FTSST) is a pivotal measure of functional mobility and independence in older adults, reflecting the ability to perform essential daily activities. Age-related declines in lower limb strength and balance are major contributors to poor FTSST performance. This study aimed to investigate the effects of an 8-week intervention combining unstable resistance training with transcranial direct current stimulation (tDCS) on FTSST outcomes. Methods Fifty-four older adults (aged 60–70 years) were randomly assigned to three groups: Unstable resistance training combined with active tDCS (Active tDCS group) or sham tDCS (Sham tDCS group), and a control group without any intervention. Forty-five participants ( n  = 15 per group) completed the 8-week intervention and were included in the final analysis. FTSST duration, isokinetic knee extension torque, center of pressure (COP) area of 1-min single-leg stance, and surface electromyography (sEMG) signals from seven lower limb muscles during FTSST test were assessed before and after the intervention. Group differences were analyzed using repeated‑measures ANOVA and analysis of covariance (ANCOVA) with Bonferroni correction. Results The Active tDCS group showed significantly greater improvements than the Sham tDCS group in FTSST total time ( p  = 0.05, Cohen’s d = 0.72) and knee extension strength ( p  = 0.011, d  = 1.10). Both training groups outperformed the control group in all functional outcomes (all p  < 0.05). ANCOVA revealed that active tDCS provided additional benefits in agonist muscle efficiency during both concentric and eccentric phases, whereas the reduction in antagonist co‑activation was similar between the two training groups. Conclusion Unstable resistance training combined with either active or sham tDCS can both improve the FTSST outcomes. Specifically, the active tDCS may bring additional training gains on the basis of unstable resistance training. The improvement of FTSST outcomes may be related to the enhanced capacity of the neuromuscular system to produce maximal muscle force and maintain movement stability as a result of training adaptations.

The majority of existing studies find that Chinese residents would like to send children to study abroad for higher education quality and multiple opportunities. Previous studies have paid little attention to the association of this issue with environmental degradation in recent years. Merging data on adults from the China Family Panel Studies (CFPS) in 2016 with data on children, this paper investigates the effect of environmental concern on the educational level at which Chinese residents are willing to send children to study abroad based on the ordered logit model and Heckman Probit Model (HPM). The results show that environmental concern predicted a positive attitude toward a willingness to send children to study abroad at a decreased schooling level after concerns about the Chinese education system and educational expectations for children and other sociodemographic factors were controlled for. The marginal effects of environmental concern on expectations of sending children to study abroad at different educational levels showed that increasing environmental concern leads to the probability of residents considering sending children to study abroad during junior college or below increasing, while it leads to the probability of residents considering sending their children to study abroad during undergraduate or higher education decreasing. The HPM further verified that environmental concern had a positive effect on residents' willingness of sending their children to study during junior college or below. The study offers an important early step in the empirical testing of the relationship between Chinese residents' environmental concern and the educational level at which they would consider sending children to study abroad.

A warm-up is a critical procedure in sports science for enhancing muscular performance and optimizing subsequent athletic activities. However, the physiological and athletic performance effects of a warm-up are often transient, diminishing rapidly during the period of inactivity after the warm-up, which is known as the warm-up transition phase. In this study, a multi-functional thermoregulation wearable composite film of graphene–MXene–bacterial cellulose/polyethylene glycol (G-M-BC/PEG) was developed by integrating MXene (a two-dimensional material with good photothermal conversion performance) and graphene into a bacterial cellulose aerogel framework, subsequently impregnated with polyethylene glycol (PEG-2000). The film showed stable structure, efficient solar photothermal conversion and storage (SPCS), and improved mechanical properties. Under 1 sun irradiation, the optimized G-M-BC/PEG wearable film showed excellent SPCS performance, sustaining a temperature plateau of 38–40 °C for 10 min after the xenon lamp was switched off under 1 sun irradiation, with a leakage rate of only 5.32% after five cycles. By constructing a biomimetic sports human body model, the composite aerogel was shown to significantly elevate muscle surface temperature and effectively mitigate heat loss during the transition phase. In the warm-up effectiveness and sports performance tests, the wearable film improved 200 m sprint performance by 0.8% ± 0.4% (p = 0.039). It also maintained subjective thermal sensation during the warm-up transition phase, with no significant decline at 5 or 10 min after the warm-up and a significant decrease only at 15 min (p = 0.02), while thermal comfort remained stable, suggesting improved neuromuscular readiness. This research provided a novel strategy for the fabrication of advanced aerogel-based wearable devices aimed at precision thermal management and athletic performance optimization.