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There is growing interest in using canopy temperature (Tc), including crop water Stress index (CWSI), for irrigation management. However, Tc varies greatly in one day, while soil water content (SWC) varies little, which may lead to different conclusions on whether irrigation is needed based on CWSI at different times. For this end, Tc of winter wheat was continuously monitored, and the data of such environmental factors as atmospheric temperature and soil water content (SWC) were simultaneously collected. CWSI was calculated based on empirical formulation and Tc and CWSI were generalized based on the normalization formulation. The correlation SWC between Tc and CWSI before and after generalization was compared and error analysis was based on SWC theoretical formula. The results showed: (1) the accuracy of SWC retrieval by Tc and CWSI increased firstly and then decreased with time during the day. The optimal time for Tc monitoring SWC was between 10:00 ~ 16:00 (R2 > 0.72) and the optimal time for CWSI monitoring SWC was between 9:00 ~ 18:00 (R2 > 0.69). (2) CWSI and Tc were mapped based on the relationship between crop water stress and soil water deficit and normalized canopy temperature expressions characterized the relationship between crop water stress and soil water deficit. (3) The accuracy of inversion of SWC by mapping Tc from 18:00 ~ 8:00 is increased from 0.5 ~ 0.6 to 0.7 ~ 0.8; the accuracy of soil water content inversion by mapping CWSI from 18:00 ~ 8:00 was improved from 0.2 ~ 0.4 to 0.4 ~ 0.6. (4) The theoretical expression of SWC deduced based on CWSI also proves that considering the relationship between crop water stress and soil water deficit change can effectively reduce the relative error from 30 to 5% in the morning and evening. This study contributes to the understanding of the reason why the correlation between Tc and SWC varies greatly during the day and solves the time-limited problem of thermal infrared remote sensing monitoring of crop water stress. [ABSTRACT FROM AUTHOR]

Exploring the impact of different monitoring angles from unmanned aerial vehicle (UAV) on the monitoring accuracy of soil moisture content (SMC) is crucial for precision irrigation. To this end, experiment was conducted to monitor the SMC of winter wheat at different growth stages under different irrigation treatments in Yangling, Shaanxi, China. At a solar zenith angle of 45°, multispectral remote sensing data from a UAV were collected at thirteen different monitoring zenith angles. Simultaneously, the SMC in the wheat root zone was measured. From the UAV multispectral images, spectral reflectance was extracted for the construction of vegetation indices. Then the correlation between the vegetation indices and the measured SMC was analyzed. With the vegetation indices as input variables, SMC monitoring models were constructed using Extreme Learning Machine (ELM), Random Forest (RF), and Back Propagation Neural Network (BPNN). The study also examined the effect of specific angles (hotspot and dark spot angles) on the estimation accuracy of the SMC at the nadir angle. The results indicated that different monitoring angles significantly impact the SMC estimation accuracy. Band reflectance and vegetation indices exhibited significant peak values and angular effects at the monitoring zenith angle of 45°. The models achieved the optimal inversion accuracy at the hotspot angle (at a monitoring zenith angle of 45° in the solar principal plane), and the accuracy was ranked as follows: BPNN (R2 = 0.71; RMSE = 1.69) > ELM (R2 = 0.52; RMSE = 1.94) > RF (R2 = 0.48; RMSE = 2.10). By eliminating shadows at the nadir angle through the threshold of dark spot, inversion accuracy similar to the hotspot direction is achieved. This study provides a basis for appropriate selection of UAV flight angles for the monitoring of SMC in the root zone of winter wheat. [ABSTRACT FROM AUTHOR]

Cu/Sn-9Zn-30Cu/Cu 3D packaging solder joints were prepared by transient liquid phase (TLP) bonding. The effect of bonding time on microstructure, shear strength, and fracture surfaces of the solder joints was studied. The results show that the interface reaction zone of Cu/Sn-9Zn-30Cu/Cu solder joints consisted of Cu6(Sn, Zn)5 phase and Cu3Sn phase at a bonding time of 15 min. With increasing bonding time, the scallop-type Cu6(Sn, Zn)5 phase gradually transformed into the layer-type Cu3Sn phase, and the thickness of the interfacial intermetallic compound (IMC) layer gradually increased. The interfacial reaction zone entirely consisted of the layer-type Cu3Sn after bonding for 60 min. The in situ reaction zone of Cu/Sn-9Zn-30Cu/Cu solder joint consisted of Cu6(Sn, Zn)5, Cu3Sn, Cu particles, and Zn-rich phase at a bonding time of 15 min. The Cu6(Sn, Zn)5 increased content and evenly distributed in the in situ reaction zone at 30 min, resulting the microstructure gradually refined. The Zn-rich phase disappeared in the in situ reaction zone after bonding 90 min, and the in situ microstructure gradually coarsened and cracks initiated as bonding time increased. The shear strength of solder joints first increased and then declined with increasing bonding time, and the maximum shear strength reached 22.25 MPa at a bonding time of 60 min. The fracture location of the solder joint shifted from the in situ reaction zone to the interface reaction zone with increasing bonding time, and the fracture mechanism of the solder joints always exhibited brittle fracture. [ABSTRACT FROM AUTHOR]

The pursuit of fabricating high‐performance graphene films has aroused considerable attention due to their potential for practical applications. However, developing both stretchable and tough graphene films remains a formidable challenge. To address this issue, we herein introduce mechanical bond to comprehensively improve the mechanical properties of graphene films, utilizing [2]rotaxane as the bridging unit. Under external force, the [2]rotaxane cross‐link undergoes intramolecular motion, releasing hidden chain and increasing the interlayer slip distance between graphene nanosheets. Compared with graphene films without [2]rotaxane cross‐linking, the presence of mechanical bond not only boosted the strength of graphene films (247.3 vs 74.8 MPa) but also markedly promoted the tensile strain (23.6 vs 10.2 %) and toughness (23.9 vs 4.0 MJ/m3). Notably, the achieved tensile strain sets a record high and the toughness surpasses most reported results, rendering the graphene films suitable for applications as flexible electrodes. Even when the films were stretched within a 20 % strain and repeatedly bent vertically, the light‐emitting diodes maintained an on‐state with little changes in brightness. Additionally, the film electrodes effectively actuated mechanical joints, enabling uninterrupted grasping movements. Therefore, the study holds promise for expanding the application of graphene films and simultaneously inspiring the development of other high‐performance two‐dimensional films. [ABSTRACT FROM AUTHOR]

The pursuit of fabricating high‐performance graphene films has aroused considerable attention due to their potential for practical applications. However, developing both stretchable and tough graphene films remains a formidable challenge. To address this issue, we herein introduce mechanical bond to comprehensively improve the mechanical properties of graphene films, utilizing [2]rotaxane as the bridging unit. Under external force, the [2]rotaxane cross‐link undergoes intramolecular motion, releasing hidden chain and increasing the interlayer slip distance between graphene nanosheets. Compared with graphene films without [2]rotaxane cross‐linking, the presence of mechanical bond not only boosted the strength of graphene films (247.3 vs 74.8 MPa) but also markedly promoted the tensile strain (23.6 vs 10.2 %) and toughness (23.9 vs 4.0 MJ/m3). Notably, the achieved tensile strain sets a record high and the toughness surpasses most reported results, rendering the graphene films suitable for applications as flexible electrodes. Even when the films were stretched within a 20 % strain and repeatedly bent vertically, the light‐emitting diodes maintained an on‐state with little changes in brightness. Additionally, the film electrodes effectively actuated mechanical joints, enabling uninterrupted grasping movements. Therefore, the study holds promise for expanding the application of graphene films and simultaneously inspiring the development of other high‐performance two‐dimensional films. [ABSTRACT FROM AUTHOR]

Continuous time-series spectral data are important for inversion of crop or soil information. UAV remote sensing is usually selected under clear and windless weather conditions, but it is not possible to have such weather every day, which results in the UAV not collecting continuous daily spectral information. To explore this issue, we focused on summer maize with four irrigation levels as the research subject. A UAV platform with a multispectral sensor was used to acquire measured spectra of the maize canopy. The solar zenith angle was calculated and substituted into the Ambrals kernel-driven model to obtain simulated spectral data for the maize canopy, and the time-series UAV spectral data were complemented. Then, four vegetation indices (VIs) were established using simulated and measured spectral data, respectively, and the accuracy of the simulated VIs was evaluated. Finally, the simulated and measured VIs were used to monitor and evaluate variations in soil surface moisture content, respectively, and provide irrigation warning. The results demonstrated that Ambrals kernel-driven model can be used to simulate the reflectance of maize canopy collected by UAV. The simulated reflectance can complement time-series UAV spectral data and be used to establish VIs, among which Structure Intensive Pigment Index (SIPI) was established with the highest accuracy (R = 0.729). The VIs established by simulated reflectance can be used to monitor soil surface moisture content, and the monitoring effect is similar to the measured data (R2 = 0.642, RMSE = 0.42). It can evaluate the soil moisture a few days after irrigation and ensure the continuity and timeliness of soil moisture data, so as to improve the crop irrigation system and carry out irrigation warning. These results have certain reference for the supplementation of time-series spectral data and farmland irrigation using UAV multispectral remote sensing. [ABSTRACT FROM AUTHOR]

Time–frequency analysis methods represent an efficacious approach to process data derived from full-waveform acoustic logging. This research proposes a coupled time–frequency analysis method that synergistically incorporates ensemble empirical mode decomposition, fractional Fourier transform, Choi–Williams (CW) distribution and adaptive filtering. This coupled method facilitates the comprehensive analysis of full-waveform acoustic logging signals within rigid geological formations. Specifically, it is designed to explore the time–frequency characteristics of shear wave (S-wave) within the context of igneous reservoirs. The coupled time–frequency analysis method significantly ameliorates the time–frequency coupling phenomenon of full-waveform acoustic logging signal. This coupled method is applied across different wells to confirm its wide-ranging applicability and study the time–frequency characteristics response of S-wave through the information of the peak time of the S-wave, the main frequency and the amplitude of the CW distribution. [ABSTRACT FROM AUTHOR]

The capture and conversion of carbon dioxide (CO2) into valuable chemical products under mild conditions is an important and challenging approach for contemporary industry. Carboxylic acid ligands are widely used in the development of functionalized metal organic framework materials due to their excellent stability. Herein, a novel mixed-metal organic framework Cu-TCPP(Fe) was assembled from iron-(Fe)-porphyrin ligands, which can efficiently catalyze the reaction of propargylic amines and CO2 to synthesize 2-oxazolidinones. [ABSTRACT FROM AUTHOR]

When calculating the CWSI, previous researchers usually used canopy temperature and atmospheric temperature at the same time. However, it takes some time for the canopy temperature (Tc) to respond to atmospheric temperature (Ta), suggesting the time-lag effects between Ta and Tc. In order to investigate time-lag effects between Ta and Tc on the accuracy of the CWSI inversion of photosynthetic parameters in winter wheat, we conducted an experiment. In this study, four moisture treatments were set up: T1 (95% of field water holding capacity), T2 (80% of field water holding capacity), T3 (65% of field water holding capacity), and T4 (50% of field water holding capacity). We quantified the time-lag parameter in winter wheat using time-lag peak-seeking, time-lag cross-correlation, time-lag mutual information, and gray time-lag correlation analysis. Based on the time-lag parameter, we modified the CWSI theoretical and empirical models and assessed the impact of time-lag effects on the accuracy of the CWSI inversion of photosynthesis parameters. Finally, we applied several machine learning algorithms to predict the daily variation in the CWSI after time-lag correction. The results show that: (1) The time-lag parameter calculated using time-lag peak-seeking, time-lag cross-correlation, time-lag mutual information, and gray time-lag correlation analysis are 44–70, 32–44, 42–58, and 76–97 min, respectively. (2) The CWSI empirical model corrected by the time-lag mutual information method has the highest correlation with photosynthetic parameters. (3) GA-SVM has the highest prediction accuracy for the CWSI empirical model corrected by the time-lag mutual information method. Considering time lag effects between Ta and Tc effectively enhanced the correlation between CWSI and photosynthetic parameters, which can provide theoretical support for thermal infrared remote sensing to diagnose crop water stress conditions. [ABSTRACT FROM AUTHOR]

To analyze the diagnostic value of quantitative features in multimodal magnetic resonance imaging (MRI) images to construct a radio-omics model for breast cancer. Methods: Ninety-five patients with breast-related diseases from January 2020 to January 2021 were grouped into the benign group (n=57) and malignant group (n=38) according to the pathological findings. All cases were randomized as the training group (n=66) and validation group (n=29) in a 7:3 ratio based on the examination time. All subjects were examined by T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), dynamic contrast enhancement (DCE), and apparent diffusion coefficient (ADC) multimodality MRI. The MRI findings were analyzed against pathological findings. A diagnostic breast cancer radiomics model was constructed. The diagnostic efficacy of the model in the validation group was analyzed, and the diagnostic efficacy was analyzed via the ROC curve. Results: Fibroadenoma accounted for 49.12% of benign breast diseases, and invasive ductal carcinoma accounted for 73.68% of malignant breast diseases. The sensitivity of T1WI, T2WI, DWI, ADC, and DCE in diagnosing breast cancer was 61.14%, 66.67%, 73.30%, 78.95%, and 85.96%, using the four-fold table method. The area under the curves (AUCs) of T1WI, T2WI, DWI, ADC, and DCE for diagnosing breast cancer were 0.715, 0.769, 0.785, 0.835, and 0.792, respectively. The AUCs of plain scan, diffuse, enhanced, plain scan + diffuse, plain scan + enhanced, enhanced + diffuse, and plain scan + enhanced + diffuse for diagnosing breast cancer were 0.746, 0.798, 0.816, 0.839, 0.890, 0.906, and 0.927, respectively. Conclusion: The construction of a radio-omics model by quantitative features in multimodal MRI images was valuable in the diagnosis of breast cancer. The value of radio-omics models such as plain scan + enhanced + diffuse was higher than the other models in diagnosing breast cancer and could be widely applied in clinical practice. [ABSTRACT FROM AUTHOR]

In this paper, we study a type of p-Laplacian equation - Δ p u = λ u p - 2 u + u q - 2 u , x ∈ R N , with prescribed mass ∫ R N | u | p 1 p = c > 0 , where 1 < p < q < p ∗ : = pN N - p , p < N , λ ∈ R is a Lagrange multiplier. Firstly, we prove the existence of normalized solutions to p-Laplacian equations and provide accurate descriptions; secondly, we discuss the existence of ground states; finally, we study the radial symmetry of normalized solutions in the mass supercritical case. Besides, we also study normalized solutions to p-Laplacian equation with a potential function V(x) - Δ p u + V (x) u p - 2 u = λ u p - 2 u + u q - 2 u , x ∈ R N , under different assumptions on q and the constraint norm c, we prove the existence, nonexistence, concentration phenomenon and exponential decay of normalized solutions. [ABSTRACT FROM AUTHOR]

To quickly and accurately obtain the moisture status of grape plants at the field scale, the treatments included three irrigation levels i.e. W3 (100%M, M as the irrigation quota), W2 (75% M) and W1 (50%M) and four fertilizer application rates i.e. F0 (0 kg/hm2), F1 (324 kg/hm2), F2 (486 kg/hm2) and F3 (648 kg/hm2). Grape leaf water content (LWC) was monitored nondestructively by an unmanned aerial vehicle (UAV) carrying multispectral (MS), visible light (RGB) and thermal infrared (TIR) cameras to extract band reflectance (BR), canopy coverage (CC) and canopy temperature (T) information, respectively. Using BR (included six bands: B, R, G, RE, NIR800, and NIR900), CC and T and their combinations as input variables brought into the partial least squares (PLS), random forest (RF), support vector machine (SVM) and extreme learning machine (ELM) algorithms. The prediction models for grape LWC were established by using four machine learning algorithms, and the optimal combination of variables was finally determined. The results represented that (1) the model built with BR + CC + T as predictor variables under different water treatments was better than other combinations of variables, with the coefficient of determination (R2) above 0.69 and the relative root mean square error (RRMSE) less than 2.5%; (2) modeling the LWC of grapes at different fertility periods based on the combination of BR + CC + T, the R2 ranged from 0.51 to 0.78 at the shoot-growing, anthesis, and fruit-inflating stages; (3) the top three important variables were T, NIR800, and NIR900 in the shoot-growing, anthesis, and fruit-inflating stages, while the top three important variables were RE, B, and T in the fruit-inflating stage. In summary, UAV multimodal data fusion has good application in predicting the LWC of grapes using RF algorithm modeling during the different growth stages. This study can supply a technical support for precise management of vineyard water regime using a UAV platform. [ABSTRACT FROM AUTHOR]

In this paper, we are concerned with the following weighted integral system involving Wolff potential: 1.1 u (x) = R 1 (x) W β , γ v q | y | σ (x) , u (x) > 0 , x ∈ R N , v (x) = R 2 (x) W β , γ u p | y | σ (x) , v (x) > 0 , x ∈ R N , where γ > 2 , β > 0 , 0 < σ < β γ < N , p , q > γ - 1 , with γ - 1 p + γ - 1 , γ - 1 q + γ - 1 < N - β γ N , γ - 1 p + γ - 1 + γ - 1 q + γ - 1 = N - β γ + σ N , R 1 , R 2 are double bounded in R N and W β , γ (h) (x) : = ∫ 0 ∞ ∫ B t (x) h (y) d y t N - β γ 1 γ - 1 dt t. Firstly, by applying Minkowski’s inequality and the regularity lifting lemma, we prove the optimal integrability, boundedness and vanishing property at infinity of integrable solutions for the system. Secondly, we use the method of moving planes in integral forms to prove the radial symmetry of the integrable solutions when R 1 ≡ R 2 ≡ 1 in R N . [ABSTRACT FROM AUTHOR]

A multisubstructure-based method for assessing the deformation and stress of a fine-meshed model according to a coarse model was proposed. Integrating boundary conditions in a local fine-meshed model, a displacement mapping matrix from the coarse model to the fine-meshed model was constructed. The method was verified by a three-level panel in a fluid–structure interaction (FSI) framework by integrating the steady vortex lattice method (VLM). A comparison between the inner deformation distribution of the coarse model and that of the global fine-meshed model obtained from MSC.Nastran was carried out, and the results showed that the coarse model failed to demonstrate reliable strains and stresses. In contrast, the proposed method in this paper can effectively depict the inner deformation and critical stress distribution. The deformation error was lower than 8%, meeting engineering requirements. Moreover, the results of different working conditions can achieve a similar relative error of displacement for an identical position. The easy storage of the displacement mapping matrix and the convenience of the boundary information transformation among all substructure levels are prominent aspects. As a result, there is a solid foundation for addressing the time-dependent problem in spite of the simultaneity and region. [ABSTRACT FROM AUTHOR]

The Arrhenius equation is generally adopted for the application of accelerated aging in laboratory tests, and activation energy is one of the important parameters in the equation. In most cases, activation energy was determined by obtaining a series of viscosity data at different temperature, which was a complex process. Therefore, this study aimed to analyze the correlation between activation energy for viscous flow (Eη) and molecular characteristics as well as rheological properties and obtain easily measurable properties that can be used to predict Eη. In this study, nine base asphalt binders were subjected to accelerated aging, and their viscosity, rheological properties, and molecular weight distribution were tested. Small molecule size (SMS) content was the most strongly correlated parameter with Eη for unaged asphalt binder compared with medium molecule size (MMS) content and large molecule size (LMS) content from the result of gray relation analysis. The correlation further weakened after considering aging, which indicated that the change in molecular distribution of asphalt binder may not be the decisive parameter in determining the change in Eη of asphalt binder. Single regression analysis showed a significant correlation between rheological performance parameters and Eη. It was feasible to predict Eη based on the failure temperature and obtain the modified Arrhenius equation. The modified equation could be used to calculate the accelerated aging factor and obtain the aging asphalt and accurate aging status of asphalt binders. By verification, the average error in predicting the Eη of the asphalt binder using the modified equation was less than 5%. [ABSTRACT FROM AUTHOR]

Aims: Quantitative characterization of the time-lag effect between canopy temperature and atmospheric temperature and its controlling factors in the agricultural ecosystem may contribute to a higher inversion accuracy of soil water content using canopy-air temperature information. Methods: Tc of winter wheat were continuously monitored, and the data of such environmental factors as solar radiation (Rs), atmospheric temperature (Ta), relative humidity (RH) and soil water content (SWC) were simultaneously collected. Results: Hysteresis existed between Tc and Ta over the diel cycles, and different weather and irrigation levels did not change the direction of the time lag loop. the key driver regulating the diel hysteresis pattern between Tc and Ta varied under different weather: on rainy days, key driver was Rs while on cloudy and sunny days, the key driver was RH. the multiple regression model indicated that together Rs, Ta, RH, and SWC explained 58 ± 10% of the variation of time-lag effect. Path analysis showed on rainy days the key driver (Rs and RH) could enhance the time-lag effect through other indirect factors (Ta and SWC); on cloud days the key driver (RH and SWC) could inhibit the time-lag effect through other indirect factors (Ta); On sunny days this mutual inhibition was further significant. Conclusions: These findings indicated a dynamic process of time-lag effect between Tc and Ta with different weather and different irrigation levels. This study contributes to the understanding of the time-lag effect and its driving factors and this analysis provides the basis for further improvement in monitoring crop water deficit. [ABSTRACT FROM AUTHOR]

The single-column model, with its advantages of low computational cost and fast execution speed, can assist users in gaining a more intuitive understanding of the impact of parameters on the simulated results of climate models. It plays a crucial role in the study of parameterization schemes, allowing for a more direct exploration of the influence of parameters on climate model simulations. In this paper, we employed various methods to conduct sensitivity analyses on the 11 parameters of the Single Column Atmospheric Model (SCAM). We explored their impact on output variables such as precipitation, temperature, humidity, and cloud cover, among others, across five test cases. To further expedite experimentation, we utilized machine learning methods to train surrogate models for the aforementioned cases. Additionally, three-parameter joint perturbation experiments were conducted based on these surrogate models to validate the combined parameter effects on the results. Subsequently, targeting the sensitive parameter combinations identified from the aforementioned experiments, we further conducted parameter tuning for the corresponding test cases to minimize the discrepancy between the results of SCAM and observational data. Our proposed method not only enhances model performance but also expedites parameter tuning speed, demonstrating good generality at the same time. [ABSTRACT FROM AUTHOR]

Crop water stress index (CWSI) has been widely used in soil moisture monitoring. However, the influence of the time lag effect between canopy temperature and air temperature on the accuracy of soil moisture monitoring with different CWSI models has not been further investigated. Therefore, based on the continuous record of canopy temperature and air temperature, this study explored the influence of canopy-air temperature hysteresis on the diagnosis of soil moisture with three CWSI models (CWSIT—theoretical, CWSIE—empirical, CWSIH—hybrid). The results show (1) the peak time of canopy temperature was ahead of that of air temperature, and the lag time varied under different soil moisture conditions. When the soil moisture was seriously deficient, the lag time decreased. However, from jointing-heading period to filling-ripening period, the lag time became longer. (2) The values of CWSIT, CWSIE, and CWSIH decreased when the time lag effect was considered. In jointing-heading period, heading-filling period, and filling-ripening period, CWSIT had the highest accuracy in soil moisture monitoring without the consideration of the time lag effect. When the time lag effect was considered, the monitoring accuracy of CWSIE and CWSIH was greatly improved and higher than that of CWSIT, while that of CWSIT was reduced. The findings provided a basis for further improving the accuracy of soil moisture monitoring with CWSI models. [ABSTRACT FROM AUTHOR]

Aims: Combining multiple features of UAV-based multispectral images with the stacking ensemble model, to improve the feasibility and accuracy of evaluating water stress in winter wheat. Methods: UAV-based multispectral images of winter wheat with different moisture treatments were acquired, from which the features such as spectrum, texture, and color moments were extracted. The soil moisture content (SMC) as well as fuel moisture content (FMC), plant moisture content (PMC), and above-ground biomass (AGB) were collected for charging the degree of water stress. The basic models were used to build ensemble models such as stacking and weighted stacking (WE-stacking), and we estimated SMC, FMC, PMC and AGB combined with multiple features. The performance of these models was evaluated. Results: The more severe the water stress, the lower values of SMC, FMC, PMC and AGB were obtained with estimation models. The performance of estimation models based on multi-feature fusion outperformed single feature in the evaluation of winter-wheat water stress. In the estimation of SMC, both stacking and WE-stacking models performed better than the basic models. Compared to the stacking model, the WE-stacking model had higher accuracy, with R2 increased between 1.98% and 3.62% at different soil depths. The WE-stacking model with multi-feature fusion still had sufficient stability and high accuracy in FMC, PMC and AGB estimation, with R2 of 0.866, 0.881 and 0.884, respectively. Conclusions: The multi-feature fusion of UAV multispectral images combined with WE-stacking model has great application potential and provides technical support in evaluating crop water stress. [ABSTRACT FROM AUTHOR]

Non‐Hermitian Hamiltonians may still possess real eigenvalues in case of the existence of parity‐time (PT) symmetry. Exceptional points (EPs) occur at the phase transition from real to complex eigenvalues due to PT‐symmetry breaking in the parameter space. Magnonic devices use magnons to carry, transport, and process information, which have the advantages of low energy dissipation, wave‐based computing, and nonlinear data processing. The combination of PT‐symmetry and magnonics may lead to novel physics as well as unprecedented functional device applications. Recently, the research of PT‐symmetry in magnetism has developed rapidly. In this review, the theoretical predictions as well as experimental findings of PT‐symmetry in magnetism are summarized. First, a brief introduction to PT symmetry, EPs, and anti‐PT symmetry is presented. Second, the theoretical and experimental progress of magnonic PT symmetry are summarized. Third, the theoretical predictions of higher‐order EPs and anti‐PT symmetry in magnonic systems are given. Finally, the study concludes by discussing the future challenges and research prospects in magnonic PT‐symmetry, and proposals for experimental observations of magnonic higher‐order EPs and anti‐PT symmetry are suggested. [ABSTRACT FROM AUTHOR]

Grassland degradation can substantially reduce soil carbon sequestration capacity. However, the effects of grassland degradation on soil organic carbon (SOC) density remain unquantified in high‐altitude alpine meadows. In this study, the response and controlling mechanisms of topsoil (0–20 cm) organic carbon were explored in a field survey involving 11 pairs of healthy versus severely degraded plots of high‐altitude (above 4000 m) alpine meadows, as well as three short‐term (3–5 years) fencing restoration projects, across the source of the Yellow River in August of 2020 and 2021. The results showed that 0–20 cm root biomass, SOC content (SCC), and density (SCD) of healthy meadows averaged 533.7 ± 291.9 g/m2 (mean ± S.D), 21.17 ± 9.36 g/kg, and 4.54 ± 1.64 kg C/m2, respectively. Root biomass, SCC, and SCD were markedly reduced by 63.0%, 33.2%, and 17.6% in severely degraded grassland compared with healthy meadows. The SCC and SCD averaged 7.92 ± 2.21 g/kg and 2.2 ± 0.9 kg C/m2 in fencing plots, respectively, and were not significantly different from severely degraded meadows, suggesting a limited improvement in SOC from short‐term fencing restoration. Analysis of a piecewise structural equation model revealed that the effect of degradation on SCD (indicated by the difference in SCD between paired healthy and degraded meadows) was jointly regulated by the differential surface root biomass and site altitude, with a total positive effect of 0.39 and 0.26, respectively. Our findings indicate the losses of topsoil organic carbon stock caused by grassland degradation are root biomass‐ and altitude‐dependent, supporting the notion that antecedent prevention of degradation, more than subsequent restoration, should be the highest priority in the adaptive management of alpine meadows in harsh high‐altitude regions. [ABSTRACT FROM AUTHOR]

In this paper we study the nonlinear Bose–Einstein condensates Schrödinger system { − Δ u 1 − λ 1 u 1 = μ 1 u 1 3 + β u 1 u 2 2 + κ (x) u 2 in R 3 , − Δ u 2 − λ 2 u 2 = μ 2 u 2 3 + β u 1 2 u 2 + κ (x) u 1 in R 3 , ∫ R 3 u 1 2 = a 1 2 , ∫ R 3 u 2 2 = a 2 2 , where a 1 , a 2 , μ 1 , μ 2 , κ = κ (x) > 0 , β < 0 , and λ 1 , λ 2 are Lagrangian multipliers. We use the Ekeland variational principle and the minimax method on manifold to prove that this system has a solution that is radially symmetric and positive. [ABSTRACT FROM AUTHOR]

Body-conformable light-emitting devices have generated considerable interest because of their widespread potential applications in aerospace, medicine and electronics. These devices, which are flexible, stretchable and soft, can integrate seamlessly and inconspicuously with the human body for tasks such as real-time monitoring, display of information, biosensing, optogenetic stimulation and medical therapy. At present, designs can be roughly divided into three different types: wearable light-emitting textiles, attachable light-emitting skins and implantable light-emitting biodevices. Here we evaluate recent advances in all three areas, discussing the materials design, device engineering strategies and diverse applications of these devices. The outstanding challenges and issues that need to be resolved before achieving widespread adoption and improved capabilities are highlighted. The progress made in developing light-emitting technologies that are wearable, attachable or implantable is reviewed and potential applications and challenges are discussed. [ABSTRACT FROM AUTHOR]

By bifurcation and topological methods, we study the existence/nonexistence and multiplicity of one-sign or nodal solutions of the following k-th mean curvature problem in Minkowski spacetime r N − k v ′ 1 − v ′ 2 k ′ = λ N C N k r N − 1 H k (r , v) in (0 , R) , | v ′ | < 1 in (0 , R) , v ′ (0) = v (R) = 0. As a previous step, we investigate the spectral structure of its linearized problem at zero. Moreover, we also obtain a priori bounds and the asymptotic behaviors of solutions with respect to λ. [ABSTRACT FROM AUTHOR]

Nitrogen is a fundamental component for building amino acids and proteins, playing a crucial role in the growth and development of plants. Leaf nitrogen concentration (LNC) serves as a key indicator for assessing plant growth and development. Monitoring LNC provides insights into the absorption and utilization of nitrogen from the soil, offering valuable information for rational nutrient management. This, in turn, contributes to optimizing nutrient supply, enhancing crop yields, and minimizing adverse environmental impacts. Efficient and non-destructive estimation of crop LNC is of paramount importance for on-field crop management. Spectral technology, with its advantages of repeatability and high-throughput observations, provides a feasible method for obtaining LNC data. This study explores the responsiveness of spectral parameters to soybean LNC at different vertical scales, aiming to refine nitrogen management in soybeans. This research collected hyperspectral reflectance data and LNC data from different leaf layers of soybeans. Three types of spectral parameters, nitrogen-sensitive empirical spectral indices, randomly combined dual-band spectral indices, and "three-edge" parameters, were calculated. Four optimal spectral index selection strategies were constructed based on the correlation coefficients between the spectral parameters and LNC for each leaf layer. These strategies included empirical spectral index combinations (Combination 1), randomly combined dual-band spectral index combinations (Combination 2), "three-edge" parameter combinations (Combination 3), and a mixed combination (Combination 4). Subsequently, these four combinations were used as input variables to build LNC estimation models for soybeans at different vertical scales using partial least squares regression (PLSR), random forest (RF), and a backpropagation neural network (BPNN). The results demonstrated that the correlation coefficients between the LNC and spectral parameters reached the highest values in the upper soybean leaves, with most parameters showing significant correlations with the LNC (p < 0.05). Notably, the reciprocal difference index (VI6) exhibited the highest correlation with the upper-layer LNC at 0.732, with a wavelength combination of 841 nm and 842 nm. In constructing the LNC estimation models for soybeans at different leaf layers, the accuracy of the models gradually improved with the increasing height of the soybean plants. The upper layer exhibited the best estimation performance, with a validation set coefficient of determination (R2) that was higher by 9.9% to 16.0% compared to other layers. RF demonstrated the highest accuracy in estimating the upper-layer LNC, with a validation set R2 higher by 6.2% to 8.8% compared to other models. The RMSE was lower by 2.1% to 7.0%, and the MRE was lower by 4.7% to 5.6% compared to other models. Among different input combinations, Combination 4 achieved the highest accuracy, with a validation set R2 higher by 2.3% to 13.7%. In conclusion, by employing Combination 4 as the input, the RF model achieved the optimal estimation results for the upper-layer LNC, with a validation set R2 of 0.856, RMSE of 0.551, and MRE of 10.405%. The findings of this study provide technical support for remote sensing monitoring of soybean LNCs at different spatial scales. [ABSTRACT FROM AUTHOR]

In this paper, we study Liouville-type theorems for fractional Hardy–Hénon elliptic systems with weights. Because the weights are singular at zero, we firstly prove that classical solutions for systems in R N \ { 0 } are also distributional solutions in R N . Then we study the equivalence between the fractional Hardy–Hénon system and a proper integral system, and we obtain new Liouville-type theorems for supersolutions and solutions by the method of integral estimates and scaling spheres respectively. [ABSTRACT FROM AUTHOR]

Exploring the potential association between peripheral blood leukocyte counts and breast cancer risk by Mendelian randomization (MR) analysis methods. Genetic data related to peripheral blood sorting counts of leukocytes were collected from a genome-wide association study by Blood Cell Consortium (BCX). Single nucleotide polymorphic loci predicting peripheral blood sorting counts of these leukocytes were selected as instrumental variables according to the correlation assumption, independence assumption and exclusivity assumption of MR. The data on breast cancer and its subtypes were obtained from Breast Cancer Association Consortium (BCAC) and FinnGen Consortium. In this study, the Inverse-Variance Weighted (IVW), Weighted Median, MR-Egger, Maximum Likelihood (ML), MR-PRESSO and Constrained Maximum Likelihood and Model Averaging (cML-MA) methods of random effects models were used for MR analysis. Cochran's Q analysis, and MR-Egger intercept analysis were applied for sensitivity analysis. IVW and cML-MA were considered the primary analytical tools, and the results of the other 4 MRs were used as complementary and validation. The results suggest that there is no significant causal relationship between leukocyte count and breast cancer risk (IVW OR = 0.98 [95% CI: 0.93–1.03], p-value = 0.35; CML-MA OR = 1.01 [95% CI: 0.98–1.05], p-value = 0.51). In addition, we analyzed whether there was a potential correlation between the five main types of categorized leukocyte counts and different breast cancer subtypes. We did not find significant evidence to support a significant correlation between leukocyte counts and breast cancer subtypes. [ABSTRACT FROM AUTHOR]

Understanding how drought is impacted by both natural and human influences is crucial to the sustainable utilization and protection of water resources. We established a drought severity index (DSI) based on the terrestrial water storage anomaly (TWSA) derived from the GRACE satellite to detect drought characteristics and trends over ten major river basins in China from 2002 to 2017. The influence of natural factors (terrestrial water storage components, precipitation, evapotranspiration, runoff, NDVI, and teleconnection factors (ENSO, PDO, NAO, and AO)) and a human factor (LULC) on drought were investigated and quantified from the perspective of water storage components based on the Theil–Sen trend and Mann–Kendall test method, the perspective of climate change based on cross wavelet transforms, and the perspective of water balance based on Random Forest. The results indicated that (1) almost all humid and arid basins experienced major drought periods during 2002–2006 and 2014–2017, respectively. The southern IRB and central YZRB regions exhibited notable declines in DSI trends, while the majority of the HLRB, IRB, LRB, YRB, HRB, and SWRB experienced significant increases in DSI trends; (2) abnormal groundwater decreases were the main cause of drought triggered by insufficient terrestrial water storage in most basins; (3) ENSO was the strongest teleconnection factor in most humid basins, and NAO, PDO, and AO were the strongest teleconnection factors in the arid basins and PRB. Most significant resonance cycles lasted 12–64 months in 2005–2014; and (4) the influence of an anthropogenic driver (LULC) has become as important as, or more important than, natural factors (runoff and teleconnection factors) on hydrological drought. [ABSTRACT FROM AUTHOR]

Organic optoelectronic devices, such as thin-film transistors, solar cells and light-emitting diodes, have drawn increasing interest because of their promising applications in sensing, energy conversion, optical imaging and optogenetic therapy. With the rapid development of wearable/implantable devices, there is a growing demand for next-generation highly stretchable optoelectronics. Conventional optoelectronic devices are usually constructed based on brittle indium tin oxide electrodes, which cannot meet the needs above, so it is essential to investigate novel electrodes with excellent stretchability. Poly(3,4-ethylenedioxythiophene) (PEDOT) and its aqueous derivative with poly(styrene sulfonate) (PEDOT:PSS) are promising electrode materials for stretchable organic optoelectronic devices considering their low cost, high conductivity, transparency, intrinsic stretchability and solution-processability. However, pure, spin-coated PEDOT-based electrodes typically possess large sizes of at least millimeter level, and it is difficult for them to satisfy the requirements for fabricating high-resolution devices. Therefore, strategies to decrease the feature size of the PEDOT-based electrodes are critically necessary. In this review, we will carefully discuss various patterning strategies for fabricating high-resolution PEDOT and PEDOT:PSS thin-film electrode arrays and summarize their characteristics. Modification methods to further enhance the conductivity and stretchability of PEDOT-based electrodes and their applications in organic optoelectronic devices are highlighted. In the end, the outlook for future research efforts is also described. [ABSTRACT FROM AUTHOR]

Accurate determination of crops growth period plays an important role in field management and agricultural decision-making. The current work mostly extracts the crop normalized difference vegetation index curve from multi-temporal data and identifies the crop phenology based on its trend or special nodes. However, these time-series-based identification methods are difficult to be applied to practically crop monitoring tasks. In this paper, the unmanned aerial vehicle remote sensing platform is used to collect the multi-spectral images of the experimental field and identify the sunflower growth period based on the different population features during its different growth periods. According to the actual field management needs, this study obtains the plot-level sunflower growth period result by analyzing statistically the distribution area of different sunflower periods in a field plot. This study uses the data of 2018 in the study area to build the model and test its performance on the data of 2019. Through comparative experiments, PSPNet can achieve a good balance between accuracy and efficiency in this study. Further, given to time-series relationship between the adjacent growth periods classification, this paper proposes an improved loss function to weight different types of misclassification to optimize model performance. The results show that improved PSPNet with proposed weighted loss function achieves the optimal recognition accuracy of 89.01%, which provides a solution for sunflower growth period recognition based on the single-phase data. [ABSTRACT FROM AUTHOR]

In this paper, we study the Kirchhoff equation with Sobolev critical exponent$ -\left(a+b\int_{ {\mathbb{R}}^3}|\nabla u|^2\right)\Delta u = \lambda u+\mu|u|^{q-2}u+|u|^{4}u\ \ {\rm in}\ {\mathbb{R}}^3 $under the normalized constraint$ \int_{ {\mathbb{R}}^3}u^2 = c^2, $where $ a, \, b, \, c>0 $ are constants, $ \lambda, \, \mu\in{\mathbb{R}} $ and $ 20 $, we distinguish the problem into four cases: $ 2

In this paper, we consider concentration phenomenon of semiclassical states to the following 2M-component reaction–diffusion system in R × R N , ∂ t u = ε 2 Δ x u - u - V (x) v + ∂ v H (u , v) , ∂ t v = - ε 2 Δ x v + v + V (x) u - ∂ u H (u , v) , where M ≥ 1 , N ≥ 1 , ε > 0 is a small parameter, V ∈ C 1 (R N , R) , H ∈ C 1 (R M × R M , R) and (u , v) : R × R N → R M × R M . It is proved that there exist semiclassical states concentrating around the local minimum points of V under mild assumptions. The approach is variational, which is mainly based upon a new linking-type argument, iterative techniques and interior estimates for nonlinear parabolic equations. [ABSTRACT FROM AUTHOR]

Semiclosed tunnels are very common in engineering construction. They are not connected, so they easily accumulate heat. Once a fire breaks out in a semiclosed tunnel, the route for rescue workers to enter is limited, so it is tough to get close to the fire source. In this paper, taking a mine excavation roadway with local pressure ventilation as an example, the temperature field distribution and water spray fire prevention characteristics of the excavation roadway face were studied using numerical simulation and theoretical analysis. This paper provides an explanation of a dynamics-based smoke management method for water spraying in a semiclosed tunnel as well as the equilibrium relationship between droplet drag force and smoke buoyancy. A method was first developed to calculate the quantity of smoke blockage based on the thickness of the smoke congestion. The local ventilation and smoke movement created a circulating flow in the excavation face, which was discovered by investigating the velocity and temperature fields of the excavation face. The size of the high-temperature area and the pattern of temperature stratification varied due to this circulating flow. When local ventilation and sprinkler systems were operating simultaneously, when the volume of smoke was small, the smoke avoided the majority of the water spray effect with the circulation flow; however, when the volume of smoke was large, the effect of the circulation flow decreased and the smoke gathered close to the sprinkler head. At this time, the blocking effect of the water spray was significant. The mean square error analysis revealed that activating the sprinkler had the most significant cooling impact on the wall on one side of the air duct. [ABSTRACT FROM AUTHOR]

As a novel energy-harvesting device, a triboelectric nanogenerator (TENG) can harvest almost all mechanical energy and transform it into electrical energy, but its output is low. Although the micro-nano structures of triboelectrode surfaces can improve their output efficiency, they lead to high costs and are not suitable for large-scale applications. To address this problem, we developed a novel TENG coating with charge-storage properties. In this study, we modified an acrylic resin, a friction material, with nano-BaTiO3 particles and gas phase fluorination. The charge-trapping ability of nanoparticles was used to improve the output of TENG. The short-circuit current and the output voltage of coating-based TENGs featuring charge storage and electrification reached 15 µA and 800 V, respectively, without decay for longtime working. On this basis, self-powered anticorrosion and antifouling systems are designed to reduce the open circuit potential of A3 steel by 510 mV and reduce the adhesion rate of algae on the surface of metal materials. This study presents a high-output, stable, coating-based TENG with potential in practical applications for anticorrosion and antifouling. [ABSTRACT FROM AUTHOR]

Grain size has a significant effect on the mechanical properties of metals. It is very important to accurately rate the grain size number of steels. This paper presents a model for automatic detection and quantitative analysis of the grain size of ferrite–pearlite two-phase microstructure to segment ferrite grain boundaries. In view of the challenging problem of hidden grain boundaries in pearlite microstructure, the number of hidden grain boundaries is inferred by detecting them with the confidence of average grain size. The grain size number is then rated using the three-circle intercept procedure. The results show that grain boundaries can be accurately segmented by using this procedure. According to the rating results of grain size number of four types of ferrite–pearlite two-phase microstructure samples, the accuracy of this procedure is greater than 90%. The grain size rating results deviate from those calculated by experts using the manual intercept procedure by less than Grade 0.5—the allowable detection error specified in the standard. In addition, the detection time is shortened from 30 min of the manual intercept procedure to 2 s. The procedure presented in this paper allows automatic rating of grain size number of ferrite–pearlite microstructure, thereby effectively improving the detection efficiency and reducing the labor intensity. [ABSTRACT FROM AUTHOR]

To explore whether pregnancy-induced hypertension (PIH) mediates the association between pre-pregnancy body mass index (BMI) and adverse neonatal outcomes in women undergoing assisted reproductive technology (ART) for singleton pregnancies. This cohort study collected 79437 maternal data from the National Vital Statistics System (NVSS) between 2020 and 2021. Univariable and multivariable logistic regression models were applied to estimate the association between pre-pregnancy BMI and PIH in women receiving ART as well as the associations between pre-pregnancy BMI and PIH and adverse neonatal outcomes. The mediation effect of PIH on the association between pre-pregnancy BMI and adverse neonatal outcomes was estimated according to the total effect, natural direct effect, natural indirect effect, and percentage of mediation. There were 25769 participants had adverse neonatal outcomes at the end of the follow-up. After adjusting for confounding factors, an increased risk of PIH in women receiving ART was identified in those with pre-pregnancy BMI ≥25 kg/m2 [odds ratio (OR)=1.92, 95% confidence interval (CI):1.84–2.01]. Pre-pregnancy BMI ≥25 kg/m2 was associated with an increased risk of adverse neonatal outcomes (OR = 1.26, 95%CI:1.22–1.30). Women with PIH had an increased risk of adverse neonatal outcomes (OR = 1.79, 95%CI:1.71–1.87). The percentage mediated by PIH in the association between pre-pregnancy BMI and adverse neonatal outcomes was 21.30%. PIH partially mediated the association between pre-pregnancy BMI and adverse neonatal outcomes in women receiving ART, which recommends that women control weight before receiving ART. [ABSTRACT FROM AUTHOR]

Bolted spherical joints are widely used in space grid structures. However, the preload loss, which may arise from fabrication error, insufficient twist of the screw and some other unknown reasons can undermine the structural integrity and even lead to the collapse of the whole structure. Therefore, a method for evaluating the preload status of bolted spherical joints is vital to the structural health monitoring of the space grid structures. To this end, a non-destructive evaluation of the preload loss of bolted spherical joints based on time reversal acoustics (TRA) is presented. In this method, an excited signal generated by a lead zirconate titanate (PZT) patch at the bolted sphere is reconstructed after the signal recorded by another PZT patch at the bar is time-reversed and re-emitted. The deviation of the reconstructed signal from the initial signal allows identification of preload loss of the bolted spherical joint. This method is demonstrated to be effective by a finite element simulation. Furthermore, the effect of preload loss of the bolted spherical joint on its ultimate flexural capacity is studied, which highlights the necessity for the non-destructive evaluation. [ABSTRACT FROM AUTHOR]

Human skeleton contains intuitive information of motions, therefore, it has been widely studied in action analysis tasks. As a part of action analysis, traditional models human action assessment by handcrafted-feature-based methods, such as dynamic time warping (DTW). These methods only extract the similarity of particular spatiotemporal features, whereas the global spatio-temporal relevance of action analysis tends to be ignored. In this paper, we propose a regression assessment model for action spatio-temporal features, which encodes the temporal features, spatial features and fused features respectively. The self-attention mechanism is taken advantage of to fuse the decoupling features, and then the overall score of action was calculated by regression. Specifically, via structure-feature fusion adaptive graph convolutional networks (SFAGCN), our action assessment network models the deep dependence of global spatio-temporal feature to address the difficulties of limited expressive ability and generalization. Furthermore, the topology of the skeletal graph and the features of the joints are merged by decoupling the spatio-temporal correlations. To confirm the effectiveness of our assessment model, we conduct experiments on six Olympic Games assessment tasks and exceed the state-of-the-art performance in Spearman's rank correlation analysis. [ABSTRACT FROM AUTHOR]

This paper gives a quantitative account of the influence of slipstream on the aerodynamic performance of a contrarotating propeller (CRP)/wing system, and compares it with the CRP and clean wing. To accurately evaluate the complex aerodynamic interaction, the unsteady Reynolds-averaged Navier–Stokes approach using the sliding mesh method is performed at a typical freestream velocity of 30 m/s. Four different critical parameters, including the freestream angle of attack (AoA), axial spacing between the front propeller (FP) and rear propeller (RP), number of blades, and rotational speed, are considered in the present work. The results show that the thrust coefficient, power coefficient, and propulsion efficiency of the CRP/wing system change sharply and the difference in amplitude between adjacent waves is large. In particular, the propeller slipstream has a significant impact on the lift–drag performance of the wing in the case of a nonzero AoA. The presence of a wing also increases the efficiency of propulsion due to the recovery of vortices. In the case of a small axial spacing, the thrust coefficient value of the FP is significantly smaller than that of the RP. However, when the axial spacing exceeds a certain value, the opposite relationship is obtained. When the rotational speed increases from 3695 RPM to 8867 RPM, the lift coefficient and drag coefficient of the wing gradually increase. [ABSTRACT FROM AUTHOR]

We study the existence and orbital stability of normalized solutions of the biharmonic equation with the mixed dispersion and a general nonlinear term γ Δ 2 u − β Δ u + λ u = f (u) , x ∈ R N with a priori prescribed L 2 -norm constraint S a := { u ∈ H 2 (R N) : ∫ R N | u | 2 d x = a } , where a > 0 , γ > 0 , β ∈ R and the nonlinear term f satisfies the suitable L 2 -subcritical assumptions. When β ≥ 0 , we prove that there exists a threshold value a 0 ≥ 0 such that the equation above has a ground state solution which is orbitally stable if a > a 0 and has no ground state solution if a < a 0 . However, for β < 0 , this case is more involved. Under an additional assumption on f , we get the similar results on the existence and orbital stability of ground state. Finally, we consider a specific nonlinearity f (u) = | u | p − 2 u + μ | u | q − 2 u , 2 < q < p < 2 + 8 / N , μ < 0 under the case β < 0 , which does not satisfy the additional assumption. And we use the example to show that the energy in the case β < 0 exhibits a more complicated nature than that of the case β ≥ 0. [ABSTRACT FROM AUTHOR]

In this paper, we study the p-Laplacian equation with a L p -norm constraint: âˆ' Î" p u = λ | u | p âˆ' 2 u + ÎĽ | u | q âˆ' 2 u + g (u) in R N , ∫ R N | u | p d x = a p , where N â©ľ 2, a > 0, 1 < p < q â©˝ p ÂŻ â‰" p + p 2 N , ÎĽ ∈ R , g ∈ C (R , R) and λ ∈ R is a Lagrange multiplier, which appears due to the mass constraint ‖ u ‖ p = a. We assume that g is odd and L p -supercritical. When q < p ÂŻ and ÎĽ > 0, we use Schwarz rearrangement and Ekeland variational principle to prove the existence of positive radial ground states for suitable ÎĽ. When q = p ÂŻ and ÎĽ > 0 or q â©˝ p ÂŻ and ÎĽ â©˝ 0, with an additional condition of g, we obtain a positive radial ground state if ÎĽ lies in a suitable range, by the Schwarz rearrangement and minimax theorems. Via a fountain theorem type argument, with suitable ÎĽ ∈ R , we obtain infinitely many radial solutions for any N â©ľ 2 and establish the existence of infinitely many nonradial sign-changing solutions for N = 4 or N â©ľ 6. In any case mentioned above, the range of ÎĽ depends on the value of a : | ÎĽ | can be large if a > 0 is small. [ABSTRACT FROM AUTHOR]

In this paper, we study the p-Laplacian equation with a L p -norm constraint: − Δ p u = λ | u | p − 2 u + μ | u | q − 2 u + g (u) in R N , ∫ R N | u | p d x = a p , where N ⩾ 2, a > 0, 1 < p < q ⩽ p ¯ ≔ p + p 2 N , μ ∈ R , g ∈ C (R , R) and λ ∈ R is a Lagrange multiplier, which appears due to the mass constraint ‖ u ‖ p = a. We assume that g is odd and L p -supercritical. When q < p ¯ and μ > 0, we use Schwarz rearrangement and Ekeland variational principle to prove the existence of positive radial ground states for suitable μ. When q = p ¯ and μ > 0 or q ⩽ p ¯ and μ ⩽ 0, with an additional condition of g, we obtain a positive radial ground state if μ lies in a suitable range, by the Schwarz rearrangement and minimax theorems. Via a fountain theorem type argument, with suitable μ ∈ R , we obtain infinitely many radial solutions for any N ⩾ 2 and establish the existence of infinitely many nonradial sign-changing solutions for N = 4 or N ⩾ 6. In any case mentioned above, the range of μ depends on the value of a : | μ | can be large if a > 0 is small. [ABSTRACT FROM AUTHOR]

We study quasilinear elliptic equations of the form âˆ' div A (u) ∇ u + 1 2 A ′ (u) | ∇ u | 2 + V (x) u = h (u) , u ∈ H 1 ( R N ) , where N â©ľ 3 , A ∈ C 1 (R , R + ) is a bounded function, V (x) is allowed to be singular at the origin, and h ∈ C (R , R) is a general nonlinearity. Such type of equations has been derived as models of several physical phenomena corresponding to various types of A. Despite the lack of a priori compactness condition for the energy functional, we develop a new variational approach to deal with the issues of multiple radial solutions, nonradial solutions and sign-changing solutions. [ABSTRACT FROM AUTHOR]

In this paper, by the moving spheres method, Caffarelli-Silvestre extension formula and blow-up analysis, we study the local behaviour of nonnegative solutions to fractional elliptic equations \begin{align*} (-\Delta)^{\alpha} u =f(u),~~ x\in \Omega\backslash \Gamma, \end{align*} where $0 , $\Omega = \mathbb {R}^{N}$ or $\Omega$ is a smooth bounded domain, $\Gamma$ is a singular subset of $\Omega$ with fractional capacity zero, $f(t)$ is locally bounded and positive for $t\in [0,\,\infty)$ , and $f(t)/t^{({N+2\alpha })/({N-2\alpha })}$ is nonincreasing in $t$ for large $t$ , rather than for every $t>0$. Our main result is that the solutions satisfy the estimate \begin{align*} f(u(x))/ u(x)\leq C d(x,\Gamma)^{{-}2\alpha}. \end{align*} This estimate is new even for $\Gamma =\{0\}$. As applications, we derive the spherical Harnack inequality, asymptotic symmetry, cylindrical symmetry of the solutions. [ABSTRACT FROM AUTHOR]

Incorporating fibers into gravelly soil is an effective method to prevent the core wall of high earth core rockfill dams (ECRDS) from cracking. In this study, a new type of soil tensile device was used to carry out tensile tests on gravelly soil with different gravel contents and fiber contents. The test results show that as the gravel content increases from 0% to 50%, the improvement in tensile strength decreases from 48.9% to 6.4%, which means the increase in gravel content reduces the improvement in tensile strength significantly. The ultimate tensile strain, tensile strength, and post-peak tensile strength of fiber-reinforced gravelly soil are positively correlated with the fiber content. Combined with the Scanning electron microscopy (SEM) results, the reinforcement effect of the three types of fiber interfaces on the gravel soil is qualitatively analyzed, and the microscopic mechanism of the improvement of the tensile strength of fiber-reinforced gravelly soil is revealed. The energy absorption capacity (EAC) results showed that the lower the gravel content in the soil, the higher the degree of improvement in the EAC value. In practical application, it is recommended to use gravel soil with low gravel content and high fiber content. Finally, a regression model considering the gravel content and fiber content was proposed for fast predicting the tensile strength of the soil. The related results can provide references for the anti-cracking design of the core wall of high ECRDS. [ABSTRACT FROM AUTHOR]

In this study, the numerical simulation of rock specimens containing 3-D internal cracks was carried out using a finite element method based on M-integral and adaptive mesh techniques. The effects of two different crack distribution forms and five crack surface inclination angles α on the crack propagation behaviour under uniaxial tensile conditions were investigated, and the main conclusions were obtained as follows: the superposition of the stress field at the crack tip results in an asymmetric distribution of SIF along the short axis of the crack. When two vertically aligned parallel cracks show a wrapped shape, the coalescence between the cracks is an important reason for the failure of the specimen. However, there is no wrapped shape between the two collinear parallel cracks, and the individual propagation of the crack leads to the failure of the specimen. The α is an important factor that determines the difficulty of crack cracking. As α decreases, the energy release rate increases, and the specimen is more prone to failure. The numerical results in this paper are in good agreement with the physical experiments, and the research results can provide a reference for the multiple internal cracks failure process of brittle materials such as rocks. [ABSTRACT FROM AUTHOR]

The rapid and accurate acquisition of nitrogen, phosphorus and potassium nutrient contents in grape leaves is critical for improving grape yields and quality and for industrial development. In this study, crop growth was non-destructively monitored based on unmanned aerial vehicle (UAV) remote sensing technology. Three irrigation levels (W1, W2 and W3) and four fertilization levels (F3, F2, F1 and F0) were set in this study, and drip irrigation fertilization treatments adopted a complete block design. A correlation analysis was conducted using UAV multispectral image data obtained from 2019 to 2021 and the field-measured leaf nitrogen content (LNC), leaf potassium content (LKC) and leaf phosphorus content (LPC) values; from the results, the vegetation indices (VIs) that were sensitive to LNC, LKC and LPC were determined. By combining spectral indices with partial least squares (PLS), random forest (RF), support vector machine (SVM) and extreme learning machine (ELM) machine-learning algorithms, prediction models were established. Finally, the optimal combinations of spectral variables and machine learning models for predicting LNC, LPC and LKC in each grape growth period were determined. The results showed that: (1) there were high demands for nitrogen during the new shoot growth and flowering periods, potassium was the main nutrient absorbed in the fruit expansion period, and phosphorus was the main nutrient absorbed in the veraison and maturity periods; (2) combining multiple spectral variables with the RF, SVM and ELM models could result in improved LNC, LPC and LKC predictions. The optimal prediction model determination coefficient (R2) derived during the new shoot growth period was above 0.65, and that obtained during the other growth periods was above 0.75. The relative root mean square error (RRMSE) of the above models was below 0.20, and the Willmott consistency index (WIA) was above 0.88. In conclusion, UAV multispectral images have good application effects when predicting nutrient contents in grape leaves. This study can provide technical support for accurate vineyard nutrient management using UAV platforms. [ABSTRACT FROM AUTHOR]

This study sought to investigate the association between microRNA-29a (miR-29a) and cardiomyocyte apoptosis in diabetic cardiomyopathy (DCM). DCM rat model was established by treating rats with streptozotocin (STZ), followed by injection of NC or miR-29a-3p mimics into the myocardium of rats. High glucose (HG)-treated H9c2 cells were transfected with NC and miR-29a-3p mimics. DCM rats presented elevated levels of blood glucose, HbA1c, blood pressure, urine output, decreased body weight and cardiac contractile function after modeling. MiR-29a was lowly expressed in STZ-treated rats and HG-treated H9c2 cells. Upregulation of miR-29a improved cardiac structure and function and attenuated, alleviated myocardial histological abnormalities and fibrosis and lowered cardiomyocyte apoptosis in DCM rats. Meanwhile, HG promoted H9c2 cell apoptosis, while miR-29a overexpression attenuated the function of HG. Compared with control group, the protein expression of Bax, cleaved-caspase3 and Bak1 in DCM and HG groups were significantly upregulated, and the expression of Bcl-2 and Mcl-1 was downregulated, while miR-29a overexpression exerted opposite effect. Bioinformatics prediction method and western blot revealed that miR-29a directly targeted Bak1 and downregulated Bak1 expression. Overall, miR-29a regulated STZ- and HG-induced cardiomyocyte apoptosis by targeting Bak1, providing a novel understanding of the pathogenesis of DCM. [ABSTRACT FROM AUTHOR]