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Soft tissues, such as muscle could autonomously grow through re‐alignment and/or ‐combination of collagen nanofibrils upon the mechanical training. This adaptive capability is highly expected in artificial materials, particularly in hydrogel actuator. In order to avoid the failure for devices by suffering from the accumulated mechanical loading, in this work, a double layered thermo‐responsive hydrogel actuator capable of self‐strengthening was successfully prepared. In the bilayer, PVA nanocrystals with different particle sizes were uniformly distributed in each monolayer matrix, giving rise to the asymmetric structure and the resultant differentiated de‐swelling behaviors. Thus, the obtained hydrogel actuator with the semi‐interpenetrating network of P(NIPAM‐co‐NMA) can display diverse programmable transformations by varying the temperatures. The existence of PVA nanocrystals in both layers not only can enhance the mechanical strength, dramatically minimizing the collapse of hydrogel actuator in service due to the imbalance of the mechanical properties for bilayer structure, but also was greatly involved in the self‐reinforcing behavior. After repetitive tensile training with 80% strain, the tensile strength and fracture strain increased from 29.6 to 45.8 kPa and 95% to 104%, respectively. The experimental results indicated that the anisotropic orientation and strain‐induced‐crystallization for PVA crystalline domains readily occurred along the tensile direction, finally leading to the synchronous enhancement in mechanical strength for both layers. This work provides a new strategy for designing smart and robust biomimetic hydrogel systems that can be further used as the intelligent soft robotics in various fields.

Background: Emotion plays an important role in shaping our actions, choices, and cognitive functions. Recognizing their significance, electroencephalography (EEG) emerges as a suitable approach for studying and discerning emotions, given its advantages of cost-effectiveness, non-invasiveness, and exceptional temporal resolution. Methods: In the current research, we attempted to introduce a new method according to empirical mode decomposition (EMD) and convolutional neural network (CNN) for emotion recognition. The multichannel intrinsic mode functions (IMFs) extracted through EMD were segmented, and signal power in each EEG segment was calculated as feature of high/low valence and arousal states. In the proposed approach, 17 × 17 images were created from EEG signals in each emotional state according to signal power in one-second segments of extracted IMFs, which were utilized as inputs for the proposed deep learning model based on CNN. The suggested technique is utilized on the DEAP database, consisting of emotional EEG data, and its outcomes are benchmarked against relevant previous studies. Results: Our approach yielded an accuracy of 91.21% for the random splitting evaluation technique and obtained a mean accuracy of 93.24% through the Leave-One-Subject-Out cross-validation process. The findings showed that our approach outperformed the previous studies which utilized the same EEG database. Conclusions: Hence, the utilization of EMD in conjunction with CNN offers enhanced analysis capabilities to effectively detect emotions from nonstationary EEG signals due to their nonlinear and nonstationary signal processing attributes.

A reliable geological model plays a fundamental role in the efficiency and safety of mountain tunnel construction. However, regional models based on limited survey data represent macroscopic geological environments but not detailed internal geological characteristics, especially at tunnel portals with complex geological conditions. This paper presents a comprehensive methodological framework for refined modeling of the tunnel surrounding rock and subsequent mechanics analysis, with a particular focus on natural space distortion of hard-soft rock interfaces at tunnel portals. The progressive prediction of geological structures is developed considering multi-source data derived from the tunnel survey and excavation stages. To improve the accuracy of the models, a novel modeling method is proposed to integrate multi-source and multi-scale data based on data extraction and potential field interpolation. Finally, a regional-scale model and an engineering-scale model are built, providing a clear insight into geological phenomena and supporting numerical calculation. In addition, the proposed framework is applied to a case study, the Long-tou mountain tunnel project in Guangzhou, China, where the dominant rock type is granite. The results show that the data integration and modeling methods effectively improve model structure refinement. The improved model's calculation deviation is reduced by about 10% to 20% in the mechanical analysis. This study contributes to revealing the complex geological environment with singular interfaces and promoting the safety and performance of mountain tunneling.

Disturbance, vegetation productivity, and recovery are crucial for aboveground biomass carbon (AGC) dynamics. Here, we use multiple satellite-based datasets to analyze the drivers of AGC dynamics in Central Africa. During 2010–2019, deforestation induced a gross AGC loss of 102.2 ± 17.1 Tg C year−1, which was counterbalanced by an AGC increase of 116.9 ± 41.1 Tg C year−1, leading to a net gain of 14.6 ± 3.8 Tg C year−1. Compared to anthropogenic and soil factors, changes in climate-related factors (e.g., radiation) are more important for the non-deforestation AGC changes. A large AGC increase was found in the northern savannas. In moist forests, strong biomass recovery and growth largely compensated the carbon loss from deforestation and degradation. Considering the increasing resource demand due to rapid population growth, reconciling natural conservation and economic development in Central Africa remains challenging and depends on climate changes and country-specific social-economic conditions.

The control-structure interaction (CSI) between shaking table and eccentric load is one of the most important reasons causing the accuracy degradation of shaking table test. At present, the eccentric ratio (ER) of load and the coupling between actuators pose challenges to study the CSI. Thus, this paper establishes an analytical transfer function matrix of a shaking table and eccentric load. Based on the transfer function matrix, a comprehensive study is conducted to analyse the CSI effect under different eccentric ratio conditions. The analysis proves the influence of the CSI, and the CSI amplifies the actuator coupling more than 22 times at 20.00 Hz. Furthermore, a real-time CSI compensation strategy considering the actuator coupling is proposed. With the adopting of the proposed strategy, the coupling between two actuators is fully eliminated, and the correlation coefficients of ground motion records of two actuators are improved by 14.75% and 5.48%, respectively.

Due to interstitial flow and medium heat transfer, canned motor pumps (CMPs) are more susceptible to cavitation than other pumps. For CMP-driven liquid cooling systems, cavitation can reduce the heat transfer capability of the system or even lead to system overheating and failure. Therefore, it is necessary to monitor the cavitation status inside the CMP. In response to issues such as low computational efficiency and weak anti-interference capabilities, a new cavitation recognition method is proposed in this article. First, complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) combined with sample entropy is used to extract the cavitation features, and then, kernel principal component analysis (KPCA) is used to remove the redundant components in the features. Finally, the particle swarm optimization support vector machine (PSO-SVM) algorithm is applied to achieve the recognition of the cavitation states. Vibration signals in three directions of a high-speed CMP under different cavitation states are collected experimentally to construct a dataset for studying cavitation recognition. Experimental results show that the method proposed can effectively extract the cavitation features and reduce the redundant components, improving operational efficiency by 35.3% compared to the situation without reducing redundant features. The method also exhibits high recognition accuracy and better anti-interference ability. Under no interference conditions, it can achieve a recognition accuracy of 99.44%. Even under strong noise interference with an SNR of 6 dB, it can still maintain a recognition accuracy of over 90%.

As a major element of the transportation network, tunnels are unavoidably threatened by accidental loads such as vehicle bombs and tank truck explosions. The goal of this research is to explore the dynamic characteristics and damage assessment of tunnel structures under contact blast loads. First, three scaled-down reinforced concrete tunnel models were made, and the explosion test and static loading test were carried out successively to evaluate the axial residual bearing capacity, axial displacement and failure mechanism of the tunnel. Secondly, the finite element model is built by utilizing LS-DYNA, and the reliability of the finite element method is confirmed by comparing the data of the explosion test with the static loading test. At the same time, the calculation method for damage coefficient and the classification criteria for damage grade based on axial residual bearing capacity are presented. Then, based on the finite element method, the propagation process of the explosion shock wave in the tunnel and the damage mechanism of the tunnel are investigated. Finally, seven explosion scenarios are developed, the damage degree of these seven tunnels under the blast load is quantitatively analyzed, and further anti-blast design ideas are put forth. The study in this article may give an intended reference for the damage assessment, anti-explosion design and strengthening work of reinforced concrete tunnels.

Perovskite solar cells (PSCs) comprise a solid perovskite absorber sandwiched between several layers of different charge-selective materials, ensuring unidirectional current flow and high voltage output of the devices1,2. A ‘buffer material’ between the electron-selective layer and the metal electrode in p-type/intrinsic/n-type (p-i-n) PSCs (also known as inverted PSCs) enables electrons to flow from the electron-selective layer to the electrode3–5. Furthermore, it acts as a barrier inhibiting the inter-diffusion of harmful species into or degradation products out of the perovskite absorber6–8. Thus far, evaporable organic molecules9,10and atomic-layer-deposited metal oxides11,12have been successful, but each has specific imperfections. Here we report a chemically stable and multifunctional buffer material, ytterbium oxide (YbOx), for p-i-n PSCs by scalable thermal evaporation deposition. We used this YbOxbuffer in the p-i-n PSCs with a narrow-bandgap perovskite absorber, yielding a certified power conversion efficiency of more than 25%. We also demonstrate the broad applicability of YbOxin enabling highly efficient PSCs from various types of perovskite absorber layer, delivering state-of-the-art efficiencies of 20.1% for the wide-bandgap perovskite absorber and 22.1% for the mid-bandgap perovskite absorber, respectively. Moreover, when subjected to ISOS-L-3 accelerated ageing, encapsulated devices with YbOxexhibit markedly enhanced device stability.

A LiDAR network is exploited for multiple human target tracking in a complex indoor scenario. LiDAR is scattered across the surveillance area, which includes several regions. The human targets maneuver rapidly and may come close to each other. Meanwhile, lots of static objects in the scenario generate a mass of static clutter measurements. In this work, a track-before-detect (TBD) processing framework is developed for human trajectories. Initially, individual and overall clutter maps are constructed to eliminate static clutter. Then, 3-D region growth, 3-D projection (3DP), and tracklet association are applied to address the problem of multiple maneuvering targets and extended targets. In the actual experiment, five pedestrians maneuver through an area comprising two corridors and a lobby. All human trajectories can be well detected by a network containing three LiDARs without false track or missed detection even though the scenario includes closely parallel tracks and crossed tracks. The average position error of human tracks could be as low as 24 cm.

Sidechain engineering as an efficient and convenient strategy has been widely used to optimize molecular structure of photovoltaic materials for boosting power conversion efficiency (PCE) of organic solar cells (OSCs). Herein, a new Y-series acceptor named Y-ThSi with trialkylsilyl-substituted thiophene as conjugated sidechain is developed. Compared with its parental Y6 with multiple intermolecular interactions, Y-ThSi has a unitary molecular packing due to the additional steric hindrance from two-dimensional (2D)-conjugated trialkylsilyl-thiophene. Therefore, Y-ThSi shows an obviously blue-shifted absorption with an onset of ~850 nm but significantly up-shifted lowest unoccupied molecular orbital energy level. For the PM6:Y-ThSi pair, the spin-coating OSCs achieve a decent PCE of 14.56% with an impressively high photovoltage (VOC) of 0.936 V. Inspired by its high VOCand narrow absorption, Y-ThSi is introduced into near-infrared absorbing binary PM6:BTP-eC9 host to construct ternary OSCs. Thanks to the complementary absorption, optimized morphology, and minimized energy loss properties, the PM6: BTP-eC9:Y-ThSi-based OSCs offer a higher PCE of 18.34%. Moreover, our developed strategy can overcome the commonly existed PCE drop when the blade-coating towards large-scale printing is used instead. Therefore, a comparable PCE of 18.34% is achieved, which is one of the best values for the blade-coating OSCs so far.

Double steel plate concrete composite shear wall (SCSW) has been widely utilized in nuclear power plants and high-rise structures, and its shear connectors have a substantial impact on the seismic performance of SCSW. Therefore, in this study, the mechanical properties of SCSW with angle stiffening ribs as shear connections were parametrically examined for the reactor containment structure of nuclear power plants. The axial compression ratio of the SCSW, the spacing of the angle stiffening rib arrangement and the thickness of the angle stiffening rib steel plate were selected as the study parameters. Four finite element models were constructed by using the finite element program named ABAQUS to verify the experimental results of our team, and 13 finite element models were established to investigate the selected three parameters. Thus, the shear capacity, deformation capacity, ductility and energy dissipation capacity of SCSW were determined. The research results show that: compared with studs, using stiffened ribs as shear connectors can significantly enhance the mechanical properties of SCSW; When the axial compression ratio is 0.3–0.4, the seismic performance of SCSW can be maximized; with the lowering of stiffener gap, the shear bearing capacity is greatly enhanced, and when the gap is lowered to a specific distance, the shear bearing capacity has no major affect; in addition, increasing the thickness of stiffeners can significantly increase the shear capacity, ductility and energy dissipation capacity of SCSW. With the rise in the thickness of angle stiffening ribs, the improvement rate of each mechanical property index slows down. Finally, the shear bearing capacity calculation formula of SCSW with angle stiffening ribs as shear connectors is derived. The average error between the theoretical calculation formula and the finite element calculation results is 8% demonstrating that the theoretical formula is reliable. This study can provide reference for the design of SCSW.

ABSTRACT CFRP confined expansive concrete (CCEC) has shown higher inflection load, intercept load and ultimate load than CFRP confined unexpansive concrete (CCUC) counterparts under axial compression. The aim of this [...]

BelL and HrmJ are α-ketoglutarate-dependent nonheme iron enzymes that catalyze the oxidative cyclization of 6-nitronorleucine, resulting in the formation of two diastereomeric 3-(2-nitrocyclopropyl)alanine (Ncpa) products containing trans-cyclopropane rings with (1′R,2′R) and (1′S,2′S) configurations, respectively. Herein, we investigate the catalytic mechanism and stereodivergency of the cyclopropanases. The results suggest that the nitroalkane moiety of the substrate is first deprotonated to produce the nitronate form. Spectroscopic analyses and biochemical assays with substrates and analogues indicate that an iron(IV)-oxo species abstracts proS-H from C4 to initiate intramolecular C–C bond formation. A hydroxylation intermediate is unlikely to be involved in the cyclopropanation reaction. Additionally, a genome mining approach is employed to discover new homologues that perform the cyclopropanation of 6-nitronorleucine to generate cis-configured Ncpa products with (1′R,2′S) or (1′S,2′R) stereochemistries. Sequence and structure comparisons of these cyclopropanases enable us to determine the amino acid residues critical for controlling the stereoselectivity of cyclopropanation.

In order to solve the problems that most models are complex, time-consuming, and have difficulty in identifying image errors, an image identification and error correction method of test report based on deep reinforcement learning and the internet of things platform in the smart lab was proposed. Firstly, a smart lab architecture was designed based on the internet of things platform, achieving efficient operation of the laboratory through cloud edge collaboration. Then, the depth separable convolution improved convolutional neural network is used to extract image features, and the features are input into bidirectional recurrent neural networks (BiLSTM) for analysis to complete image recognition. Finally, the ICNN-BiLSTM model is used as the agent of reinforcement learning, and image error correction is completed by identifying the distance between the image and the key points of the reference image. Based on the Python platform, the proposed method was experimentally demonstrated, and the results showed that its average error correction accuracy reached 96.75%, with a processing time of 15.37s.

The medium-bandgap polymerized small molecule acceptors (PSMAs) have broad application scenarios. However, the effort in the molecular design of the high-performance medium-bandgap PSMAs is limited. In this article, we introduce alkoxy groups as outer side chains and as substituents of the thiophene π-bridges of the high-performance PSMA PY-IT to synthesize a medium-bandgap PSMA PO-TO. Due to that the non-covalent interaction between the alkoxy groups and the terminal groups of the small molecule acceptor (SMA) unit can weaken the intramolecular charge transfer (ICT) effect, the bandgap of PO-TO is enlarged and its absorption is blue-shifted compared with PY-IT, while the absorbance of PO-TO solution and film is enhanced significantly compare with that of PY-IT. When blended PO-TO with the polymer donor PBQx-TF, the corresponding all-polymer solar cells (all-PSCs) exhibit an open-circuit voltage (Voc) exceeding 1.04 V with a power conversion efficiency (PCE) of 13.75%. Furthermore, PO-TO was used as the third component to fabricate ternary all-PSCs with PBQx-TF as the polymer donor and PY-IT as the main polymer acceptor, and the ternary all-PSCs based on PBQx-TF:PY-IT:PO-TO (1:1:0.2, w/w/w) demonstrated a high PCE of 17.71% with simultaneously improved Vocof 0.940 V, short-circuit current density (Jsc) of 24.60 mA cm−2and fill factor (FF) of 76.81%. In comparison, the binary all-PSCs based on PBQx-TF:PY-IT showed a PCE of 16.77%. This result indicates that introducing alkoxy groups is a promising strategy for synthesizing high-performance medium-bandgap PSMAs.

ABSTRACT The main objectives of this study are to conduct principle analysis of mix design and evaluate the performance of the Buton rock asphalt (BRA) modified Superpave mixture through wheel [...]

Evotherm is one of the chemical warm mix asphalt (WMA) technologies that has been widely used in sustainable asphalt pavement construction. But the long-term performance of such warm mix asphalt [...]

The cytochrome P450 (CYP) AspB is involved in the biosynthesis of the diketopiperazine (DKP) aspergilazine A. Tryptophan-linked dimeric DKP alkaloids are a large family of natural products that are found in numerous species and exhibit broad and often potent bioactivity. The proposed mechanisms for C-N bond formation by AspB, and similar C-C bond formations by related CYPs, have invoked the use of a ferryl-intermediate as an oxidant to promote substrate dimerization. Here, the parallel application of steady-state and transient kinetic approaches reveals a very different mechanism that involves a ferric-superoxide species as a primary oxidant to initiate DKP-assembly. Single turnover kinetic isotope effects and a substrate analog suggest the probable nature and site for abstraction. The direct observation of CYP-superoxide reactivity rationalizes the atypical outcome of AspB and reveals a new reaction manifold in heme enzymes.

As the interest in use of waxy wheat in food applications continues to grow, it is important to fully understand characteristics of waxy wheats. To the best of our knowledge, there was no previous study reporting a complete characterization of commercial waxy wheats developed in China, especially properties of wheat kernels, dough, wet milling, gluten, and starch. To promote the industrial utilization of waxy wheat, four Chinese commercial waxy wheats were collected and characterized. Four commercial waxy wheats commercialized in China were sound medium hard wheats. Care must be taken during harvesting and storage of waxy wheats since the waxy wheat flours were very sensitive to the endogenous α‐amylase even at a very low level of enzyme activity. Rapid viscosity analyzer had a good potential for evaluating the sprout damage of waxy wheat. Dough rheological properties and gluten index showed that the four waxy wheats had weak gluten quality, agreeing with wet‐milling performance. The waxy wheat starches had higher onset, peak, and conclusion gelatinization temperatures than normal wheat starch. While the waxy wheat starches showed lower pasting temperature and higher peak viscosity than normal wheat starch. Results suggested that the four commercial waxy wheats varied in kernel characteristics, protein and starch contents, wet‐milling performance, gluten quality, dough rheological properties and pasting properties, which might provide a wide range of applications. The research work provides useful information for wheat breeders to breed waxy wheat suitable for industrial applications and for scientists to promote the use of waxy wheat flour and starch in food applications.

ABSTRACT Foaming warm mix asphalt (WMA) is a green asphalt technology that has been widely used in recent years. This study evaluates the effect of curing time on the material [...]

• A novel plasticine-like conductive hydrogel conduit was designed. • The hydrogel exhibited good moldability and electroactive properties. • The plasticine-like conductive hydrogel favored dorsal root ganglion axon extension. • The plasticine-like conductive hydrogel enhanced peripheral nerve regeneration in mice models. In recent years, electrically conductive hydrogel-based nerve guidance conduits (NGCs) have yielded promising results for treating peripheral nerve injuries (PNIs). However, developed ones are generally pre-manufactured and exhibit a limited ability to achieve good contact with nerve tissue with irregular surfaces. Herein, we developed a plasticine-like electrically conductive hydrogel consisting of gelatin, conducting polypyrrole, and tannic acid (named GPT) and assessed its ability to promote peripheral nerve regeneration. The shape-persistent GPT hydrogel exhibited good self-healing properties and could easily be molded to form a conduit that could match any injured nerve tissue. Their electrical properties could be tuned by changing the PPy concentration. In vitro , the improved conductivity of the hydrogel promoted dorsal root ganglion (DRG) axonal extension. More importantly, we found that the GPT hydrogel enhanced axonal regeneration and remyelination in vivo , preventing denervation atrophy and enhancing functional recovery in a mice model of sciatic nerve injury. These results suggest that our plasticine-like NGC has huge prospects for clinical application in the repair of PNI. [Display omitted] A plasticine-like conductive hydrogel was developed with self-healing and shape persistent properties. The hydrogel could be easily molded to form a conduit that could match any injured nerve tissue and facilitate axonal regeneration and remyelination in vivo , thus enhancing peripheral nerve regeneration and functional recovery in mice with sciatic nerve injury [ABSTRACT FROM AUTHOR]

Recent public opinion polls conducted in Europe and the United States show increasingly negative views of China. Does the Chinese public hold similar views of “the West”? Conducting a two-wave survey in China, we found great divergence and asymmetries in Chinese public perceptions. First, Chinese views of European countries and the US diverge sharply, despite these countries being typically grouped together as “the West” in mainstream English and Chinese discourses; the Chinese viewed the US much more negatively than Europe. Second, whereas the Chinese reciprocated American antipathy, there was an asymmetry in public perceptions between China and Europe, with the Chinese expressing much greater favourability towards European countries than the other way around, though the degree of favourability still varied by country. Analyses of respondent attributes also yielded insights that both confirm and challenge some of the conventional wisdom regarding age, education, and party membership in Chinese public opinion.

In order to examine the effect of spatial scale and building exposure distribution on the pure rate of earthquake catastrophe insurance, this study described three modules for rate determination, put forward the general assumptions and principles for calculating the pure insurance rate, and introduced three types of building distribution and their calculation. Taking Tangshan City of Hebei Province in China as an example, we analyzed the pure rate of regional earthquake insurance in terms of spatial scale and building exposure distribution by using the method of control variables. The results show that for districts (or counties) with large differences in seismic risk, the risk areas can be further divided to apply differential rates. In areas with a diverse distribution of potential earthquake source areas and large differences in building density, there is a risk of overestimating or underestimating the pure rate of earthquake insurance when buildings are distributed evenly or partially evenly. This violates the break-even principle of rate setting. This study also provides a reference for earthquake catastrophe insurance companies to choose the spatial scale and the detailed level of exposure distribution in rate determination.

The development and utilization of urban underground space is producing many deep foundation pits. On-site monitoring is a key issue to ensure the safety of the foundation excavation, especially the monitoring of the lateral displacement of the structure. The ultra-deep circular foundation excavation project (58.65 m deep, the deepest foundation pit in Shanghai) in the test section of the Suzhou River deep tunnel is one of the most challenging engineering around the world. The distributed optical fiber monitoring technology of Brillouin optical frequency domain analysis (BOFDA) was employed to monitor the lateral displacement of the deep foundation. The monitoring process lasted for 14 months, and a total of 19 times of monitoring was carried out following the progress of the excavation of the foundation pit. This paper introduces the process, methods and precautions of optical fiber monitoring from early installation, equipment debugging to data acquisition, data processing and data analysis. By comparing the fiber monitoring data with the manual monitoring data, the deformation of the deep foundation excavation is analysed. The analysis results not only obtain the deformation law of ultra-deep foundation excavation, but also prove the advantages of optical fiber monitoring in deep foundation excavation. Finally, with the support of the Smart Infrastructure Service System (iS3), the research combines optical fiber monitoring with an information platform. Under the framework of the iS3 platform, an integrated data processing and analysis module for fiber monitoring is developed, and the feasibility of remote real-time collection and analysis of monitoring data is discussed. With the support of the information platform, the monitoring data can be transmitted back to the computer terminal to realize remote monitoring.

Hyperspectral image classification has two key characteristics: spatial dependency and class imbalance. The synthetic oversampling methods for solving the between-class imbalance have the problem of spatial information loss to some extent. However, the feature space optimization methods for solving data within-class complex distribution problems have not been studied extensively. To remedy such an issue, we propose in this article an improved spectral–spatial feature rotation-based support vector machine (SVM) ensemble method (SSFRoS). More precisely, in the data preprocessing stage and from the perspective of sample space optimization, we devise a spectral–spatial neighborhood-based adaptive synthetic sampling algorithm (SSAS) that focuses adaptively on hard-to-learn samples, with artificial samples interpolated in the spectral–spatial neighborhood to further utilize the spatial information. In the feature rotation stage and from the perspective of feature space optimization, we innovatively discover that the class overlapping problem can be handled by combining feature extraction, to achieve the goal of reducing the difficulty of imbalanced classification. Besides, the SVM and voting procedure are used in the ensembled classification stage. We then conduct a series of experiments to compare the proposed SSFRoS with several baselines in terms of seven metrics. The results show that SSFRoS has significant advantages in dealing with imbalanced hyperspectral image classification problems. In addition, a detailed ablation study shows that the lowest class recall can be improved by 46.67% and 5.26% at Indian Pines and Pavia University, respectively, which demonstrates that using SSAS can enhance the recognition of hard-to-learn classes.

Changes in terrestrial carbon storage under environmental and land-use changes remain a critical source of uncertainty in regional and global carbon budgets. We generated global maps of annual live vegetation biomass using L-band microwave vegetation optical depth. Globally, biomass carbon stocks increased from 2010 to 2019 at a rate of 0.50 ± 0.20 PgC yr−1with a year-to-year variability, closely mirroring the observations of the global atmospheric CO2growth rate. The main contributors to the global carbon sink are boreal and temperate forests, while wet tropical forests are small carbon sources, from deforestation and agriculture-related disturbances. We found that the tropical deforested and degraded old-growth forests (>140 yr) are nearly carbon neutral whereas temperate and boreal young (< 50 yr) and middle-aged (50–140 yr) forests are the largest sinks. By contrast, dynamic global vegetation models show that all old-growth forests are large sinks and largely ignore the impacts of deforestation and degradation on tropical biomass. Our findings highlight the importance of forest demography when predicting dynamics of future carbon sink under changing climate.

Herein, a concise and robust approach for the highly efficient assembly of [60]fullerene-fused tricyclic scaffolds has been developed through a palladium-catalyzed cascade [2 + 2 + 2] annulation process. Diverse tricyclic scaffolds incorporating various ring sizes (6–19 membered) and types (carbocycles and N- and O-heterocycles) can be expediently constructed in a single-step transformation.

Reducing energy loss (Vloss) is one of the most crucial challenges in organic photovoltaic cells. The Vloss, determined by the differences between the optical band gap (Eg) of the active layer material and the open-circuit voltage (Voc) of the device, is generally alleviated by lowering the energy difference between the lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO) level of the donor (D) and acceptor (A). In this work, we synthesized two A-π-D-π-A-type small-molecule donors (SMDs) SM-benzotriazole (BTz)-1 and SM-BTz-2 by introducing a BTz π-bridge unit and terminal regulation. The BTz π-bridge unit significantly lowers the HOMO energy level of SMDs, resulting in high Vocand high mobility, achieving a balance of low energy loss (<0.5 eV) and high efficiency. Ultimately, the organic solar cells based on SM-BTz-2 as the donor and Y6 as the acceptor obtain a high Vocof 0.91 V, Jscof 22.8 mA cm−2, fill factor of 68%, and power conversion efficiency (PCE) of 14.12%, which is one of the highest efficiencies based on the SMDs with triazole π-bridges to date. What’s more, the BTz π-bridge unit is a potential unit that can improve mobility and reduce energy loss.

Centrifugal pumps are widely used in life applications and engineering applications in agriculture, fishery, chemical industry, hydropower plants, energy and power engineering, and the main bottlenecks of centrifugal pump applications lie in the adjustment mode of centrifugal pump, energy loss and pump operation stability. Energy loss in centrifugal pumps not only reduces pump efficiency but also determines pump life. The main contribution of this paper is to propose an intelligent optimization algorithm-particle swarm optimization algorithm based on centrifugal pump regulation method and energy loss analysis method. This method can quickly search the global and find the global optimal value, so as to find the most suitable adjustment method and reduce energy consumption. According to the experimental findings of this work, the search efficiency of the traditional PSO algorithm ranges from 25% to 41% in five trials on the search ability of the PSO algorithm before and after the enhancement. The search efficiency of the improved PSO algorithm is the lowest of 72% and the highest of 89%. It can be seen that the search efficiency of the improved PSO algorithm is twice that of the classic PSO algorithm. Therefore, the improved PSO algorithm is more suitable to be applied to the intelligent search for suitable adjustment methods and energy consumption analysis of centrifugal pumps. The improved PSO algorithm finds that the most energy-saving adjustment method is to combine the two adjustment methods into a joint adjustment method. Therefore, the improved PSO algorithm proposed in this paper is of great significance to reduce the energy consumption of centrifugal pumps. This paper first expounds the importance of centrifugal pump, and expounds its current problems, and then proposes an intelligent optimization algorithm to improve the adjustment method of centrifugal pump, and proposes the PSO algorithm before and after enhancement. By comparison, it is found that the improved PSO algorithm is more suitable for intelligent search and energy consumption analysis of suitable adjustment methods of centrifugal pumps.

The influence of tunnel longitudinal shear deformation on the response of its adjacent ground building is investigated based on a 2D analytical model considering a flexible circular tunnel and a shear wall standing on a semi-circular rigid foundation under SH-waves excitation. Soil-tunnel relative stiffness is introduced, and a closed-form analytical solution is presented for the system response. Tunnel stiffness significantly affects the foundation impedance function of the building. Rayleigh scattering frequency can accurately predict the position of the fluctuation peaks of the foundation impedance function. At locations where the tunnel–building interaction is strong, the tunnel cannot be considered as rigid even if the tunnel relative stiffness to the soil reaches 100. At locations where constructive and destructive wave interference occurs, the building relative response increases or decreases accordingly. Considering the influence of tunnel relative stiffness, the amplitude of the building relative response can be amplified by 27.0% or reduced by approximately 28.0%, respectively. This analytical model is also used to qualitatively predict the amplitude of the relative response transfer function of the Hollywood Storage Building under the influence of the tunnel longitudinal shear deformation, and its accuracy is verified.

For formulate an effective maintenance scheme of submarine pipeline and effectively ensure the safe operation of submarine pipeline, a strength evaluation and reliability technology of energy pipeline based on Fuzzy depth learning network algorithm is proposed. Firstly, the influence factors of marine environment on submarine pipeline corrosion are described. Secondly, the reliability model of corroded submarine pipeline is established. Given the uncertainty of the relevant parameters of the corrosion defect, the equation of state of the corrosion protection pipe shall be determined on the basis of the corrosion pressure analysis of the corrosion protection pipe. A vague in-depth networking algorithm is used to calculate the probability of a rusty pipeline failure. The results show that the probability of corrosion of the pipeline increases rapidly over time. When the time is 22 years, the failure probability is 2 × 10−4. When the time is 30a, the failure probability is 3.1 × 10−3. The feasibility of fuzzy deep learning network algorithm is verified.

AbstractThis study investigates how individuals may develop more or less strong beliefs in the indivisibility of a disputed territory and how such beliefs may influence their policy preferences toward resolving the dispute. Using a survey experiment in Japan, we find that historical ownership strengthens respondents’ beliefs in territorial indivisibility. Furthermore, those who hold the strongest belief in territorial indivisibility are much less likely to support bilateral negotiation and more likely to support contentious policies, including but not limited to military actions. Finally, we explore external validity of the findings by analyzing respondents who had a real dispute in mind during the survey with China, South Korea, and Russia, respectively.

In the framework of the RECCAP2 initiative, we present the greenhouse gas (GHG) and carbon (C) budget of Europe. For the decade of the 2010s, we present a bottom‐up (BU) estimate of GHG net‐emissions of 3.9 Pg CO2‐eq. yr−1(using a global warming potential on a 100 years horizon), which are largely dominated by fossil fuel emissions. In this decade, terrestrial ecosystems acted as a net GHG sink of 0.9 Pg CO2‐eq. yr−1, dominated by a CO2sink that was partially counterbalanced by net emissions of CH4and N2O. For CH4and N2O, we find good agreement between BU and top‐down (TD) estimates from atmospheric inversions. However, our BU land CO2sink is significantly higher than the TD estimates. We further show that decadal averages of GHG net‐emissions have declined by 1.2 Pg CO2‐eq. yr−1since the 1990s, mainly due to a reduction in fossil fuel emissions. In addition, based on both data driven BU and TD estimates, we also find that the land CO2sink has weakened over the past two decades. A large part of the European CO2and C sinks is located in Northern Europe. At the same time, we find a decreasing trend in sink strength in Scandinavia, which can be attributed to an increase in forest management intensity. These are partly offset by increasing CO2sinks in parts of Eastern Europe and Northern Spain, attributed in part to land use change. Extensive regions of high CH4and N2O emissions are mainly attributed to agricultural activities and are found in Belgium, the Netherlands and the southern UK. We further analyzed interannual variability in the GHG budgets. The drought year of 2003 shows the highest net‐emissions of CO2and of all GHGs combined. We have synthesized the European budgets of carbon and the greenhouse gases (GHG) carbon dioxide, methane and nitrous oxide. This synthesis includes estimates of direct emissions from fossil fuel burning, industrial production, waste management and agriculture, as well as of sources and sinks in the terrestrial biosphere. Summing up the sources and sinks of the three GHGs, we estimate for the decade of the 2010s an average annual net‐emission of 3.9 billion tons of carbon dioxide equivalents. These net‐emissions are dominated by carbon dioxide from fossil fuel emissions (4.1 billion tons of carbon dioxide). In contrast, the terrestrial biosphere acts as a net sink of carbon dioxide, the effect of which is only partly counterbalanced by net emissions of methane and nitrous oxide. The net‐effect of the terrestrial biosphere's GHG budget is a sink of 0.9 billion tons of carbon dioxide equivalents per year. Over the last three decades, European GHG emissions have declined by 1.2 billion tons carbon dioxide equivalents per year, mainly due to reductions in fossil fuel emissions. However, the sink capacity of the terrestrial biosphere has diminished since the 2000s. We provide a bottom‐up estimate of CO2, CH4, N2O emissions of 3.9 Pg CO2‐eq. yr−1over Europe, 2010–2019Terrestrial ecosystems acted as a greenhouse gas net sink of 0.9 Pg CO2‐eq. yr−1, dominated by CO2sinkNet‐greenhouse gas emissions decreased by ∼1/4 since the 1990s, but land carbon sink is weakening since the 2000s We provide a bottom‐up estimate of CO2, CH4, N2O emissions of 3.9 Pg CO2‐eq. yr−1over Europe, 2010–2019 Terrestrial ecosystems acted as a greenhouse gas net sink of 0.9 Pg CO2‐eq. yr−1, dominated by CO2sink Net‐greenhouse gas emissions decreased by ∼1/4 since the 1990s, but land carbon sink is weakening since the 2000s

In non-high-risk individuals, risk-category-based atherosclerotic cardiovascular disease (ASCVD) screening strategies may be more cost-effective than one-size-fits-all approaches. However, current decisions are constrained by a lack of research evidence. We aimed to explore appropriate risk-category-based screening interval strategies for non-high-risk individuals in ASCVD primary prevention in the Chinese population.

The seismic fragility of the transfer and purging chamber in a nuclear power plant is assessed in this paper based on the incremental dynamic analysis method. Select the peak ground acceleration as the ground motion intensity measure, and select the compressive strain of concrete, steel plate stress, and peak displacement of the structure as the damage measures. This paper calculates the dynamic response of the transfer and purging chamber under 160 seismic conditions and analyzes the conditional failure probabilities of no damage, slight damage, recoverable damage, and serious damage. The result shows that the conditional failure probabilities of concrete and steel plate have remarkable differences under the design basis ground motions, and both are lower than the criterion restriction. The conditional failure probability of peak displacement of the cantilever in the transfer and purging chamber under the design basis ground motions exceeds the criterion restriction. It indicates that peak displacement of the cantilever is overlarge in one direction caused by insufficient constraints and too small local stiffness. The failure probability of the transfer and purging chamber that does not meet operational basis performance demand is 6.32 × 10−2‱, and the failure probability of the transfer and purging chamber that does not meet safety shutdown performance demand is 1.76 × 10−3‱.

AbstractStudies on grout consolidation after synchronous grouting around shield tunnels have ignored the expansion of the grout–groundwater interface and the difference in the permeabilities of the grout and water in the stratum. The process of grout pressure dissipation and diffusion in the stratum was solved with a two-dimensional two-phase seepage model, with which the head losses caused by grout diffusion in the stratum and groundwater seepage in the stratum under the ‘push-displacement effect’ were studied together. In addition, the influence of the temporal variation in viscosity and the infiltration effect were considered. Then, a two-phase analytical seepage model of consolidation for shield grouting considering the temporal variation in viscosity and the infiltration effect was established. A numerical algorithm was designed to solve the theoretical model with the difference method. The analytical model was verified by comparison with the results of numerical simulation. Furthermore, the main parameters in the analytical model were analysed. The results show that the temporal variation in grout viscosity and the infiltration effect greatly influence the stable pressure value and the loss rate of the volume of grout after consolidation. Among the main parameters in the model, the permeability coefficient of the stratum is the most sensitive.

Isomerization of functional groups in photovoltaic materials plays a vital role in molecular packing and their photovoltaic performance. In this work, two narrow-band gap polymer acceptors, PY5-TTz-FT and PY5-TTz-CT, are synthesized by copolymerization of the small-molecule acceptor (SMA) Y5 as the main backbone and thiophene-thiazolothiazole (TTz)-thiophene with isomerized ethylhexyl substitution on the thiophene π-bridges as the linking unit. The polymerized SMA (PSMA) PY5-TTz-CT with the ethylhexyl substituents close to the TTz unit exhibits red-shifted absorption spectra and a relatively higher lying lowest unoccupied molecular orbital (LUMO) energy level, in comparison with PY5-TTz-FT with the ethylhexyl substituents far from the TTz unit. However, PY5-TTz-CT exhibits poorer photovoltaic performance than that of PY5-TTz-FT in the all-polymer solar cells (all-PSCs) with PBDB-T as the polymer donor, due to the poor morphology of the PBDB-T:PY5-TTz-CT active layer, while the optimized all-PSC based on PBDB-T:PY5-TTz-FT shows a higher power conversion efficiency of 12.73%. The results imply that isomerization of polymer acceptors is an effective strategy to tune the molecular packing of the photovoltaic materials and photovoltaic performance of the all-PSCs.

ABSTRACTExperimental autoimmune encephalomyelitis (EAE) is characterized by demyelination of the central nervous system. Emodin is an anthraquinone derivative with comprehensive anti-inflammatory, anti-cancer, and immunomodulatory effects and is widely used in the treatment of inflammatory, tumor, and immune system diseases. However, none of the clinical or experimental studies have explored the therapeutic efficacy of emodin in EAE/multiple sclerosis (MS). Thus, we evaluated the protective effect of emodin on EAE mediated via inhibition of microglia activation and inflammation. Wild-type mice were randomly divided into the normal control, EAE, low-dose emodin, and high-dose emodin groups. Clinical scores and pathological changes were assessed 21 days after immunization. The network pharmacology approach was used to elucidate the underlying mechanisms by using an online database. Molecular docking, polymerase-chain reaction tests, western blotting, and immunofluorescence were performed to verify the network pharmacology results. An in vivoexperiment showed that high-dose emodin ameliorated clinical symptoms, inflammatory cell infiltration, and myelination. Pharmacological network analysis showed AKT1 was the main target and that emodin played a key role in MS treatment mainly via the PI3K–Akt pathway. Molecular docking showed that emodin bound well with PI3K, AKT1, and NFKB1. Emodin decreased the expression of phosphorylated(p)-PI3K, p-Akt, NF-κB, and myeloid differentiation factor 88 and the levels of markers (CD86 and CD206) in M1- and M2-phenotype microglia in EAE. Thus, the emodin inhibited microglial activation and exhibited anti-inflammatory and neuroprotective effects against EAE via the Myd88/PI3K/Akt/NF-κB signalling pathway. In conclusion, emodin has a promising role in EAE/MS treatment, warranting further detailed studies.

Glucocorticoids have been implicated as pathophysiological mediators of obesity and insulin resistance and are regulated by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). This enzyme regenerates active corticosterone from inactive 11-keto forms. To assess the role of 11β-HSD1-mediated synthesis of active corticosterone in leptin-related obesity and diabetes, we examined the peripheral effect of leptin on 11β-HSD1 activity and gene expression in vivo and in vitro in hepatocytes from ob/ob mice and in liver of streptozotocin (STZ)-treated ob/ob mice. We observed an inverse relationship between hepatic 11β-HSD1 expression and body weight in ob/ob mice and lean littermates. Leptin treatment of ob/ob mice markedly increased hepatic 11β-HSD1 activity and mRNA expression. This induction of 11β-HSD1 expression corresponded to reduced levels of circulating corticosterone and weight loss in ob/ob mice treated with leptin, indicating that impaired hepatic 11β-HSD1 expression may contribute to the pathogenesis of obesity in ob/ob mice. In addition, leptin treatment of STZ-treated ob/ob mice caused marked increases in hepatic 11β-HSD1 levels associated with decreased body weight and a significant reduction in hyperglycemia due to pancreatic β-cell damage. Addition of leptin to ob/ob mouse primary hepatocytes led to a dose-dependent increase in 11β-HSD1 mRNA expression. In contrast, leptin did not influence 11β-HSD1 expression in primary hepatocytes from db/db mice, indicating that leptin regulation of 11β-HSD1 expression is probably mediated by the functional leptin receptor. Thus, leptin appears to be an important metabolic signal that directly activates intrahepatic corticosterone production. These findings suggest that the liver-specific interaction of leptin with 11β-HSD1 is involved in the development of obesity and insulin resistance in ob/ob mice., Obesity is a significant risk factor for health and is thought to constitute a crucial component in the pathogenesis of insulin resistance, type 2 diabetes, hypertension, and cardiovascular disease (1-3). [...]

To design a gigantic microwave power transmitting array for space solar power station, modular design procedure is discussed. Besides microwave power channels, radiating array and thermal control, functions such as DC power source and beam steering should also be included in the design of the microwave power transmitting array. Smart composite structures integrate electronics, structures, thermal control and other functions into a module, providing an advanced design and integration paradigm. Modular smart composite structure antenna is an ideal candidate for its light weight and other performance.

Wounds can be produced when cells and tissues are subjected to excessive forces, for instance, under pathological conditions or nonphysiological loading. However, the cellular behaviors in the wound formation process are not clear. Here we tested the behaviors of wound formation in the epithelial layer with an in-suit uniaxial stretching device. We found that the wound often nucleates at the position where the cells are dividing. The polarization direction of cells near the wound is preferentially along the wound edge, whereas the cells far from the wound are preferentially perpendicular to the stretching direction. The larger the wound area is, the higher is the aspect ratio of the cells around the wound. Increasing the cell density will strengthen the cell layer. The higher the cell density is, the smaller is the area of the wounds, and the weaker is the effect of stretching on the polarization of the cells. Furthermore, we built a coarse-grained cell model that can explicitly consider the elasticity and viscoelasticity of cells, cell-cell interaction, and cell active stress, by which we simulated the wound formation process and quantitatively analyzed the force and stress fields in the cell layer, particularly around the wound. These analyses reveal the cellular mechanisms of wound formation behaviors in the cell layer under stretching and shed useful light on tissue engineering and regenerative medicine for biomedical applications.

Purpose: Due to the few reports on the 91Sr half-life previously, the accuracy and uncertainty of the results are difficult to meet the requirements such as calculating the cross section and the fission yields of 235U, 238U, and 239Pu. To solve the discrepancy of 91Sr half-life in existing experimental data, the half-life of 91Sr was measured in this work, and the uncertainty was discussed in detail. Method: The measurements were performed by the activation method implemented for the uranium sample using the K-400 neutron generator at the Chinese Academy of Engineering Physics (CAEP). The half-life of 91Sr was measured by γ-ray spectrometry using the high-resolution High Purity Germanium (HPGe) Detector. Results: Through exponential function fitting and a detailed discussion of the uncertainty evaluation, the half-life of 91Sr in the present work was determined to be 9.65 ± 0.30 h, which was consistent with the values reported previously and the uncertainty was reduced greatly, however, the uncertainty assessment of the latter was barely documented. Conclusions: In this work, a more accurate measurement of the 91Sr half-life is provided, as well as the uncertainty is discussed in detail. This result will provide essential information for applications using an activation method, such as the calculation of fission yields of 235U, 238U, and 239Pu.

Siberian forests are generally thought to have acted as an important carbon sink over recent decades, but exposure to severe droughts and fire disturbances may have impacted their carbon dynamics. Limited available forest inventories mean the carbon balance remains uncertain. Here we analyse annual live and dead above-ground carbon changes derived from low-frequency passive microwave observations from 2010 to 2019. We find that during this period, the carbon balance of Siberian forests was close to neutral, with the forests acting as a small carbon sink of +0.02+0.01+0.03PgC yr−1. Carbon storage in dead wood increased, but this was largely offset by a decrease in live biomass. Substantial losses of live above-ground carbon are attributed to fire and drought, such as the widespread fires in northern Siberia in 2012 and extreme drought in eastern Siberia in 2015. These live above-ground carbon losses contrast with ‘greening’ trends seen in leaf area index over the same period, a decoupling explained by faster post-disturbance recovery of leaf area than live above-ground carbon. Our study highlights the vulnerability of large forest carbon stores in Siberia to climate-induced disturbances, challenging the persistence of the carbon sink in this region of the globe.

Dentin bonding based on a wet-bonding technique is the fundamental technique used daily in clinics for tooth-restoration fixation and clinical treatment of tooth-related diseases. Limited bonding durability led by insufficient adhesive infiltration in the demineralized dentin (DD) matrix is the biggest concern in contemporary adhesive dentistry. This study proposes that the highly hydrated noncollagenous protein (NCP)-formed interfacial microenvironment of the DD matrix is the root cause of this problem. Meanwhile, the endogenous phosphate groups of the NCPs are used as pseudonuclei to rapidly induce the formation of amorphous CaF2nanoparticles in situin the interfacial microenvironment. The DD matrix is thus reconstructed into a novel porous structure. It markedly facilitates the infiltration of dentin adhesives in the DD matrix and also endows the DD matrix with anticollapsing capability when water evaporates. Whether using a wet-bonding or air-drying mode, the bonding effectiveness is greatly promoted, with the 12 month bonding strength being about twice that of the corresponding control groups. This suggests that the nanoreinforced DD matrix eliminates the dependence of bonding effectiveness on the moisture status of the DD surface controlled only by experiences of dentists. Consequently, this bonding strategy not only greatly improves bonding durability but also overcomes the technical sensitivity of bonding operations of the total-etched bonding pattern. This exhibits the potential to promote dentin bonding and is of great significance to dentistry.