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In this paper, a method with highly sensitive multi-wall carbon nanotubes (MWCNTs) film sensors was put forward to evaluate the health condition of glass fiber-reinforced composite single lap joints in real time. With this method, the single lap joint fracture can be predicted when the resistance change rate reached 1.11% to 5.89% approximately. Meanwhile, for the single lap joints, the reality can be found that the farther distance was from the interface to different layers, the more easily defect might emerge under the force introduced in the interface plane. And the stress in the middle area of the interface for the joint was greater than that in the edge when it was stretched. The results of experiments indicated that the effectiveness of MWCNTs sensors to monitor the health condition of the single lap joints was confirmed. [ABSTRACT FROM AUTHOR]

Identifying interspecific associations is very important for understanding the community assembly process. However, most methods provide only an average association and assume that the association strength does not vary along the environmental gradient or with time. The scale effects are generally ignored. We integrated the idea of wavelet and network topological analysis to provide a novel way to detect nonrandom species associations across scales and along gradients using continuous or presence–absence ecological data. We first used a simulated species distribution data set to illustrate how the wavelet correlation analysis builds an association matrix and demonstrates its statistical robustness. Then, we applied the wavelet correlation network to a presence–absence data set of soil invertebrates. We found that the associations of invertebrates varied along an altitudinal gradient. We conclude by discussing several possible extensions of this method, such as predicting community assembly, utility in the temporal dimension, and the shifting effects of highly connected species within a community. The combination of the multiscale decomposition of wavelet and network topology analysis has great potential for fostering an understanding of the assembly and succession of communities, as well as predicting their responses to future climate change across spatial or temporal scales. [ABSTRACT FROM AUTHOR]

Simple Summary: Understanding avian migratory routes is crucial for identifying important stopover sites during migration and for implementing targeted conservation efforts at these key locations. The Black-faced Spoonbill (Platalea minor) is a Class I protected species in China; however, research on it has been extremely limited to date. This study reconstructs the population-level migratory trajectories of the Black-faced Spoonbill based on citizen science data. The results indicate that Wenzhou, Xiamen, Shantou, Shanwei, Hsinchu, Chiayi, and Tainan are significant stopovers for this species. There are multiple migratory pathways for the Black-faced Spoonbill across the southeastern coastal region of China. This study also validates the application of citizen science data in restoring species migration trajectories. The findings enhance our understanding of the migratory patterns of the Black-faced Spoonbill and provide valuable insights for its conservation. Migration is a critical ecological process for birds. Understanding avian migratory routes is essential for identifying important stopover sites and key foraging areas to ensure high-quality stopovers for birds. The Black-faced Spoonbill (Platalea minor), a national Grade I protected wild animal in China, is classified as endangered on the IUCN Red List of Threatened Species. Studying the migratory routes of the Black-faced Spoonbill and identifying critical stopover sites across different life histories is vital for its conservation. However, research on the migratory routes of this species has been very limited. This study, utilizing citizen science data and the Level-order-Minimum-cost-Traversal (LoMcT) algorithm, reconstructs the migratory trajectories of the Black-faced Spoonbill from 2018 to 2022. The results show that Wenzhou, Xiamen, Shantou, Shanwei, Hsinchu, Chiayi, and Tainan are significant stopovers for this species. The Black-faced Spoonbill is actively migratory during the migration season across the southeastern coastal region of China. The simulation results of this study reveal the migratory routes and activity patterns of the Black-faced Spoonbill, providing critical support for its conservation. [ABSTRACT FROM AUTHOR]

In this study, a novel sensor with high sensitivity and linear was prepared based on two-dimensional (2D) material (MXene) and ink, which can be used for deformation and damage monitoring of structural composites. The MXene was efficiently prepared by etching Ti3AlC2 powder with LiF–HCl solution and subsequent vacuum drying. The viscosity and adhesion of MXene/ink composites were controlled by changing the ratio of solvent (dimethyl sulfoxide) to ink. The MXene/ink was printed on the surface of the composite material to avoid forming defects in the composite material. The percolation threshold of the MXene/ink nanocomposite was relatively low, 3.6wt%. In this paper, MXene/ink composites with different contents were selected as the sensor, and the characteristics of the sensor were verified through monotone stretch and cyclic load-and-unload tests. When the MXene content just exceeds the percolation threshold (4wt%), the gauge factor (GF) of the sensor is higher, the results of monotonic tensile experiment show that there are two different sensitive stages of linear change (0 ~ 0.477%) and (0.477 ~ 1.37%), and the range GF is116.6 and 554.3, respectively. In addition, the linear relationship and sensitivity of the sensor remained stable after loading and unloading tensile tests. MXene/ink sensor has a broad application prospect in damage monitoring of aerospace structural composites. [ABSTRACT FROM AUTHOR]

Particulate matter (PM), one of the most important pollutants of traffic emission, threatens the health of urban ecosystems and citizens. Roadside trees play an important role in trapping PM, and the foliar PM load is a useful indicator for air PM pollution in road systems. To detect the relationships of foliar PM load with road structures, urbanization, and meteorology in road systems, we studied a widely-planted tree Sophora japonica L. in 100 roads and 10 yards of Beijing, China, and found that the foliar PM loads increased with the distances from the urban centre (DUC) linearly, while decreased with the road density. All-subsets regression analysis indicated that DUC, average monthly relative humidity, average monthly wind speed, and mean annual wind speed were the most important factors in predicting foliar PM load, rather than general situation of buildings and road cleanliness. The monthly relative humidity and monthly wind speed had a negative correlation to foliar PM, while the annual relative humidity and annual wind speed had a positive correlation to foliar PM. Suburban areas and these effective factors should be highlighted in PM control in Beijing. [ABSTRACT FROM AUTHOR]

Abstract: Aim: To evaluate how a biotic filter (overstorey cover [OC]) shapes an elevational herb richness pattern and to test whether intermediate elevations represent more suitable habitats for herb species due to the minimal biotic and moderate abiotic filtering that occured there. Location: Dongling Mountain, China. Taxon: Herbs. Methods: We sampled herb richness along a 1,000‐m vertical transect (OC and elevation covary) and four horizontal transects (across the OC gradient with no change in elevation). Functional traits related to shade (leaf mass per area [LMA] and leaf stem ratio [LSR]) and freezing tolerance (leaf thickness [LT] and hair density [HD]) were collected based on vegetation sampling plots. We divided the richness data into below‐ and above‐timberline groups and then assessed the most important driver for each group. By estimating the variations in species richness and functional diversity along horizontal transects, we examined how these parameters responded to OC while controlling for associated differences in elevation. Results: Herb richness showed a unimodal relationship with elevation, with a peak around the timberline. Below the timberline, herb richness was better predicted by OC and showed a positive relationship with the functional diversity of LMA and LSR. The frost period performed better in predicting herb richness above the timberline, and herb richness was positively related to the functional diversity of HD. Main conclusions: The results support our hypothesis and highlight the importance of OC in shaping herb richness patterns. Below the timberline, OC acts as a filter, sorting species based on their ability to tolerate shade, whereas the frost period limits richness above the timberline and favours species that can tolerate low temperatures. Therefore, we suggest that biotic interactions, as well as environmental and geographical factors, should be considered the main drivers of elevational plant richness patterns. [ABSTRACT FROM AUTHOR]

Confidentiality and authentication are two important security properties of wireless communication. There are currently two types of research in wireless communication security: one is based on cryptography, which can be too complicated for some wireless systems; the other is based on physical layer characteristics, which has some security problems and cannot work as well as the cryptography‐based method. In this paper, a lightweight encryption and message authentication framework for wireless communication is proposed. The proposed framework has lower complexity than the cryptography‐based method and works more securely and efficiently than the classical physical layer method. For the encryption, a physical layer offered chain key (PHYLOCK) structure is proposed to generate one‐time keys, which are then XOR‐ed with the plaintext to generate the ciphertext. A security analysis of PHYLOCK is performed and it is proved that it has better security features than the traditional physical layer key generation. For the message authentication, three types of PHYLOCK‐CRC‐based message authentication schemes are developed whose generator polynomial is determined by one‐time keys generated by PHYLOCK. PHYLOCK‐CRC‐based message authentication detects not only random errors introduced by noises but also malicious attacks. The error‐detecting and anti‐attack capabilities are analyzed mathematically. Compared to the standard CRC, PHYLOCK‐CRC‐based message authentication has a decline in error correction capability but is enhanced with cryptographic security features. Monte‐Carlo simulations are provided to evaluate the proposed scheme. [ABSTRACT FROM AUTHOR]

Highlights: [·] We explored the pollution characters of metals in street dust of Beijing. [·] Area-source pollution and point-source pollution exist simultaneously. [·] We identified the spatial autocorrelation intensities and ranges of metals. [·] Metal pollution anomalies were identified by cluster and outlier analyses. [·] Urban activities strongly influence the distributions of metals. [ABSTRACT FROM AUTHOR]

[Display omitted] • The pressure monitoring range of mxene sensor reaches MPa level. • A distributed pressure measurement scheme for bolt structure interface is proposed. • Early warning monitoring of bolt looseness was achieved in vibration environment. • The results provide a reliable solution for industrial applications. Mxenes can be used in a variety of applications due to their multifunctional chemical properties. It has received increasing attention as a piezoresistive sensor. However, the stability and pressure monitoring range of the reported MXene sensors are limited, thereby limiting these scalability and effectiveness. In contrast, this paper presents a conductive MXene/FPC based pressure sensor overcomes the aforementioned shortcoming in that its pressure monitoring range and stability are improved by one order of magnitude. Therefore, this study aims to validate the use of MXene sensor for detecting bolt loosening. First, the mechanical properties of MXene were tested, including pressure test, vibration test and so on. The mechanical parameters of MXene are obtained. Secondly, the bolt structure embedded with MXene sensor is tested by torque loading and bolt looseness monitoring under vibration environment. The experimental results show that it has a linear pressure monitoring range of 0−120Mpa, the sensitivity of the sensor is up to 1.3 Mpa −1, and can remain stable after more than 63,000 cycles. Through monitoring the change of resistance ΔR/R 0 , the pressure of bolt pre tightening force transmitted to the joint surface can be accurately sensed. In the vibration environment, when the excitation frequency is 20 Hz, the bolt structure resonates, and ΔR/R 0 increases from 0.28 to 0.6; when the bolt looses in about 100 s, the ΔR/R 0 increases from 0.3 to 0.68 indicates that MXene can respond to bolt loosening in time. Thus, the sensor can be used in the whole life health monitoring of bolted structure completely. [ABSTRACT FROM AUTHOR]

The multi-level ditch system developed in the Sanjiang Plain, Northeast China has sped up water drainage process hence transferred more pollutants from farmlands into the rivers of this region. Understanding the seasonal dynamics of nitrogen (N) and phosphorus (P) transportation in the ditch system and the role of different ditch size is thus crucial for water pollution control of the rivers in the Sanjiang Plain. In this study, an investigation was conducted in the Nongjiang watershed of the Sanjiang Plain to study the nutrient variation and the correlation between water and sediments in the ditch system in terms of ditch level. Water and sediments samples were collected in each ditch level in growing season at regular intervals (once per month), and TN, NON, NH-N, TP, and PO-P were analyzed. The results show that nutrient contents in water were higher in June and July, especially in July, the contents of TN and TP were 3.21 mg/L and 0.84 mg/L in field ditch, 4.04 mg/L and 1.06 mg/L in lateral ditch, 2.46 mg/L and 0.70 mg/L in branch ditch, 1.92 mg/L and 0.63 mg/L in main ditch, respectively. In August and September, the nutrient contents in the water were relatively lower. The peak value of nutrient in ditch water had been moving from the field ditch to the main ditch over time, showing a remarkable impact of ditch system on river water environment. The nutrient transfer in ditch sediments could only be found in rainfall season. Nutrient contents in ditch sediment had effect on that in ditch water, but nutrients in ditch water and sediments had different origination. Ditch management in terms of the key factors is hence very important for protecting river water environment. [ABSTRACT FROM AUTHOR]

Abstract: The effect of oxygen plasma treatment on the non-equilibrium dynamic adsorption of the carbon fabric reinforcements in RTM process was studied. 5-Dimethylamino-1-naphthalene-sulfonylchloride (DNS-Cl) was attached to the curing agent to study the change of curing agent content in the epoxy resin matrix. Steady state fluorescence spectroscopy (FS) analysis was used to study this changes in the epoxy resin at the inlet and outlet of the RTM mould, and XPS was used to study the chemical changes on the carbon fiber surfaces introduced by plasma treatment. The interlaminar shear strength (ILSS) and flexural strength were also measured to study the effects of this non-equilibrium dynamic adsorption progress on the mechanical properties of the end products. FS analysis shows that the curing agent adsorbed onto the fiber surface preferentially for untreated carbon fiber, the curing agent content in the resin matrix maintain unchanged after plasma treatment for 3min and 5min, but after oxygen plasma treatment for 7min, the epoxy resin adsorbed onto the fiber surface preferentially. XPS analysis indicated that the oxygen plasma treatment successfully increased some polar functional groups concentration on the carbon fiber surfaces, this changes on the carbon fiber surfaces can change the adsorption ability of carbon fiber to the resin and curing agent. The mechanical properties of the composites were correlated to this results. [ABSTRACT FROM AUTHOR]

Abstract: Biodiversity index based on species richness and evenness has been a frequently used measure to describe phytoplankton community composition and the impact of water pollution on biotic components, despite it could not reflect clearly the impact of a particular species on the structure and function of phytoplankton community. On the contrary, an index based on the niche theory has been developed and used to elucidate the changes of phytoplankton community with the alteration of species composition under various levels of water quality. Through comparison on the Shannon–Wiener biodiversity index (H′) and the community pollution value (CPV), this paper depicted the algal species composition change along the gradation of water quality and quantified the impact of species composition on the structure and function of a freshwater phytoplankton community in four urban lakes in central China. This study found that not only CPV could indicate water pollution status but also the fluctuation of CPV along water pollution gradient could show the influence of dominant species composition on community function. The comparison between Shannon–Wiener biodiversity index and CPV shows that the presence of dominant species sustains the stability and the succession of phytoplankton community under the changing water environments. The results of this study indicate that the combination of biodiversity index and CPV can provide a systematic way to understand biotic interactions and species responses to altered habitats at the community level. Most importantly, these indicators will provide valuable information for lake management and restoration practices. [Copyright &y& Elsevier]

Abstract: This paper presents an approach using continuation and optimisation methods for modifying a process design to avoid control difficulties caused by input multiplicity. The approach assumes an initial design, with a preassigned SISO control structure, has been obtained and is useful where there is an input multiplicity in the operating region. The condition for input multiplicity is obtained by inflating the state space model with a state representing the locus of the point of zero gain. The multiplicity condition is determined using the bifurcation analysis package, AUTO, which allows the study of the influence of operating conditions and parameters on input multiplicity behaviour to obtain an expression for the point of zero gain as a function of the design and disturbance variables. A process modification problem is formulated within an optimisation framework and solved to determine the minimal design parameter changes necessary to avoid input multiplicity given an assumed maximal disturbance. Results are presented for the application of the algorithm to a CSTR system demonstrating that small changes in some design variables can avoid input multiplicity problems in this case, and that the method can determine the changes necessary. [Copyright &y& Elsevier]

Few studies have examined leaf-trait relationships in the distribution of individual species along an environmental gradient. Here we address the issue by testing for the leaf-trait relationships of Quercus liaotungensis, a dominant deciduous woody species in northern China, along an altitudinal gradient in Dongling Mountain, Beijing. These leaf traits included specific leaf area (SLA), leaf dry matter content (LDMC), and leaf nitrogen, phosphorus, and potassium concentration on mass basis (Nmass, Pmass and Kmass, respectively). Along the altitudinal gradient, negative relationships between SLA and LDMC and Nmass were found, and Nmass, Pmass and Kmass correlated with each other positively. Relationship between Nmass and Pmass was stronger than the ones between Nmass and Kmass, and between Pmass and Kmass. The weak and negative relationship between SLA and Nmass might result from trade-offs that limit photosynthesis and water use efficiency along the altitudinal gradient, suggesting many environmental factors of local site being the collective forcing of drivers. Out of our expectations, Nmass and Pmass related very weakly to soil N and P, and no significant relationship between Kmass and soil K was found along elevation. These relationships could be used to predict the productivity of the population with changing environment in this region. [ABSTRACT FROM AUTHOR]

Airborne particulate matter (PM) filtration by plants is a process of continuous PM accumulation and periodic washing, in which climate factors plays a key role. However, most of the relevant studies have focused on the impact of single meteorological factors, the influencing mechanism of comprehensive meteorological factors, i.e., climate, on PM filtration by plants remains unclear. Coupled with the i-Tree model, we established a multi-cycle PM removal (PMR) model with the focus on the impact of wind and precipitations on the PM filtration function of plants, so as to inform the suitability of different climates for green space creation. Interactions between relevant parameters were analyzed through simulation. It was found that the PM capture threshold of plants and the time required to reach this threshold both decreased with wind speed (V). The PMR performance of plants increased and then decreased with V, and the optimal V decreased with increasing precipitation interval (T). The performance of different climates in PMR could be ranked as: short T & high V > short T & low V > long T & low V > long T & high V. Within areas characterized by a long T, it is suitable to create green spaces in the places where V is relatively low and with the pattern of large patches and high-density to reduce plants' exposure V. Additionally, the relative magnitudes of the PMR of different plant species may change with V or T; species selection should match the regional climate. This study can help to clarify the influencing mechanism of climate factors on the PMR performance of plants and provides guidance for creating green spaces for PM control under different climate regimes. [Display omitted] • A multi-cycle particulate matter removal (PMR) model by plants was established. • The PM capture threshold of plants decreases with increasing wind speed (V). • The PMR performance of plants increases and then decreases with increasing V. • The optimal V for PMR by plants decreases with increasing precipitation interval (T). • The relative magnitudes of PMR of different plant species may change with V or T. [ABSTRACT FROM AUTHOR]

Offers information on a study which examined the effect of land use structure on the distribution of soil nutrients. Description of the study area; Experimental analysis; Results and discussion.

Preparation and sensing properties of the MXene/ink nanocomposite sensor for health monitoring. • A new strain sensor based on MXene film and printing ink encapsulated with nylon fabric, which can be manufactured by simple spraying-coated technique to meet the needs of mass production. • The unique sheet structure of MXene makes it easier to form a stable conductive network. The surface of Ti3C2Tx prepared by etching in LiF-HCl solution has a large amount of oxygen and hydroxyl groups, which are easy to disperse in aqueous solution and contribute to the improvement of strain sensing performance. The effect of different mxene ratio on ink conductivity was discussed, and a low permeability threshold was found. MXene/ink based strain sensor exhibited excellent sensitivity , low detection limit and stable sensing performance after 2950 cycles at 20% strain. • The designed MXene/ink strain sensor encapsulated with nylon fabric could be used to detect different movement behaviors and physiological signals of human body, showing a wide application prospect in the field of new flexible multi-functional sensors. Flexible strain sensors still face great challenges in combining high sensitivity, wide detection range, good mechanical stability and simple manufacturing processes into sensors. Herein, this paper reports a simple and low cost strain sensor fabricating method based on two-dimensional (2D) material (MXene) and ink, which can be large-scale fabricated into multiduty sensors with high sensitivity and excellent durability by spray-coated process and wrapped by nylon fabric. Owing to the fact that MXene has excellent dispersion in printing ink material, the sensor obtains low percolation threshold of 3.6 wt% and a percolation network based on Ti 3 C 2 T x MXene/ink composites was precisely designed. The migration of the MXene lamination leads to a large change in resistance, while the ink coating restricts the large displacement of the nanometer lamella to maintain the connectivity of the conductive path in the large strain region. The strain sensing test shows that the MXene/ink encapsulated by nylon fabric strain sensor exhibits a high sensitivity (gauge factor of 27.2 and 170.9 under 0 %–25 % and 25 %–29.7 % strain, respectively), good linearity (R-Square >0.967), and excellent reliability and stability (>2950 cycles). The as-developed MXene/ink strain sensor was demonstrated to monitor real-time both tiny and large human activities, showing that it has great potential in the field of wearable strain sensor. [ABSTRACT FROM AUTHOR]

Background: Hepatocellular carcinoma (HCC) is a highly heterogeneous cancer with major challenges in both prevention and therapy. Metformin, adenosine monophosphate‐activated protein kinase (AMPK) activator, has been suggested to reduce the incidence of HCC when used for patients with diabetes in preclinical and clinical studies. However, the possible effects of metformin and their mechanisms of action in non‐diabetic HCC have not been adequately investigated. Methods: Fah−/− mice were used to construct a liver‐injury‐induced non‐diabetic HCC model for exploring hepatocarcinogenesis and therapeutic potential of metformin. Changes in relevant tumour and biochemical indicators were measured. Bulk and single‐cell RNA‐sequencing analyses were performed to validate the crucial role of proinflammatory/pro‐tumour CD8+ T cells. In vitro and in vivo experiments were performed to confirm Cyp26a1‐related antitumour mechanisms of metformin. Results: RNA‐sequencing analysis showed that chronic liver injury led to significant changes in AMPK‐, glucose‐ and retinol metabolism‐related pathways in Fah−/− mice. Metformin prevented the formation of non‐diabetic HCC in Fah−/− mice with chronic liver injury. Cyp26a1 ddexpression in hepatocytes was significantly suppressed after metformin treatment. Moreover, downregulation of Cyp26a1 occurred in conjunction with increased levels of all‐trans‐retinoic acid (atRA), which is involved in the activation of metformin‐suppressed hepatocarcinogenesis in Fah−/− mice. In contrast, both CD8+ T‐cell infiltration and proinflammatory/pro‐tumour cytokines in the liver were significantly upregulated in Fah−/− mice during chronic liver injury, which was notably reversed by either metformin or atRA treatment. Regarding mechanisms, metformin regulated the decrease in Cyp26a1 enzyme expression and increased atRA expression via the AMPK/STAT3/Gadd45β/JNK/c‐Jun pathway. Conclusions: Metformin inhibits non‐diabetic HCC by upregulating atRA levels and downregulating CD8+ T cells. This is the first reporting that the traditional drug metformin regulates the metabolite atRA via the Cyp26a1‐involved pathway. The present study provides a potential application of metformin and atRA in non‐diabetic HCC. [ABSTRACT FROM AUTHOR]

In this study, a rubber composite was prepared based on two-dimensional (2D) material (MXene) and ethylene propylene diene rubber (EPDM). The MXene was efficiently prepared by etching Ti3AlC2 powder with LiF-HCl solution and subsequent vacuum drying, and the dispersion of MXene in EPDM was improved by optimizing the grinding process, ultrasonic stripping and stirring method. In the process of exploring the electrical conductivity of this material system, the composite exhibits low percolation threshold of 2.7 wt%, a high conductivity of 106 Sm−1 and superior thermal conductivity of 1.57 W/m K at the MXene content of 6 wt%. In addition, MXene (6 wt%)/EPDM with 0.3-mm thick exhibits an EMI shielding performances (SE) up to 48 dB in the X-band (8.2–12.4 GHz) and 52 dB in the Ku-band (12.4–18 GHz) (SE) which are much better than the electromagnetic shielding properties of other rubber blends, and these properties indicate MXene/EPDM composite has great potential for versatile applications. [ABSTRACT FROM AUTHOR]

The distributions of small rodents in mountainous environments across different elevations can provide important information regarding the effects of climate change on the dispersal of plant species. However, few studies of oak forest ecosystems have compared the elevational patterns of sympatric rodent diversity, seed dispersal, seed bank, and seedling abundance. Thus, we tested the differences in the seed disperser composition and abundance, seed dispersal, seed bank abundance, and seedling recruitment for Quercus wutaishanica along 10 elevation levels in the Taihang Mountains, China. Our results provide strong evidence that complex asymmetric seed dispersal and seedling regeneration exist along an elevational gradient. The abundance of rodents had a significant negative correlation with the elevation and the seed removal rates peaked and then declined with increasing elevation. The seed removal rates were higher at middle and lower elevations than higher elevations but acorns were predated by 5 species of seed predators at middle and lower elevations, and thus, there was a lower likelihood of recruitment compared with those dropped beneath mother oaks at higher elevations. More importantly, the number of individual seeds in the seed bank and seedlings increased with the elevation, although dispersal services were reduced at sites lacking rodents. As conditional mutualists, the rodents could possibly act as antagonistic seed predators rather than mutualistic seed dispersers at low and middle elevations, thereby resulting in the asymmetric pattern of rodent and seedling abundance with increasing elevation to affect the community assembly and ecosystem functions on a large spatial scale. [ABSTRACT FROM AUTHOR]

Avifauna are essential for maintaining the structure and functioning of mangrove ecosystems, which are particularly sensitive to habitat transformation. Although exotic cordgrass, Spartina alterniflora, is an increasing threat to mangrove ecosystems (including the associated unvegetated shoals) of China, its effects on the avifauna in such ecosystems are poorly understood. In Zhanjiang, China, the avifaunal Shannon-Weiner diversity, Simpson's diversity, Margalef's species richness, Pielou's evenness and density indices were compared in (1) an Avicennia marina monoculture vs. an S. alterniflora–invaded A. marina stand (a mixture of A. marina and S. alterniflora) and (2) an unvegetated shoal vs. an S. alterniflora–invaded shoal that had rapidly become an S. alterniflora monoculture. All avifaunal community parameters except for the Simpson index were significantly lower in the S. alterniflora + A. marina mixture than in the A. marina monoculture, and in the S. alterniflora monoculture than in the unvegetated shoal. These results indicate that the presence of S. alterniflora reduces the suitability of the Zhanjiang mangrove ecosystem for avifauna. Among the four habitats, the Shannon-Weiner diversity index, species richness, and density of the avifaunal community were highest in the unvegetated shoal. Further analysis indicated that the differences in the avifaunal community between invaded and noninvaded sites were associated with vegetation characteristics (mainly plant height and density) and macrobenthic faunal metrics (mainly species richness and density). The reduced avifaunal diversity and abundance associated with S. alterniflora invasion probably resulted from the decline in food resources or from the increased difficulty in foraging and roosting. The findings indicate that the conservation of birds in mangrove ecosystems may depend on controlling or eradicating exotic S. alterniflora, maintaining tidal mudflats, and diversifying the habitats in mangrove wetlands. [ABSTRACT FROM AUTHOR]

Mangroves are essential for maintaining local biodiversity and human well-being, and mangrove structure and functioning depend on the macrobenthos. Although exotic cordgrass, Spartina alterniflora, is an increasing threat to the mangrove wetlands (including the associated unvegetated shoals) of China, its effects on the macrobenthic fauna in such wetlands is poorly understood. The macrobenthic faunal communities were compared in (1) an Avicennia marina monoculture vs. an S. alterniflora-invaded A. marina stand (a mixture of A. marina and S. alterniflora) and in (2) an unvegetated shoal vs. an S. alterniflora-invaded shoal that had rapidly become an S. alterniflora monoculture in Zhanjiang, China. S. alterniflora invasion significantly increased plant density regardless of invaded habitat but significantly increased the contents of total carbon, organic matter, and total sulfur in the sediment only in the unvegetated shoal. The presence of S. alterniflora had little influence on indices of the macrobenthic faunal community in the A. marina monoculture, but significantly decreased the density and biomass of macrobenthic faunal community in the unvegetated shoal. These results indicate that the effects of S. alterniflora on the macrobenthic faunal community depend on which type of mangrove habitat is invaded. The composition of the macrobenthic faunal community was more similar between the invaded and non-invaded A. marina stand than between the invaded and non-invaded unvegetated shoal. Overall, the differences in the macrobenthic faunal community between invaded and non-invaded habitats were associated with increases in the sediment organic matter content and plant density. [ABSTRACT FROM AUTHOR]

Electromagnetic interference (EMI) originated from radio stations to various electronic appliances and devices is an increasingly serious problem, and there are significant interests in the development of light-weight, high-efficiency materials for EMI shielding. Herein we report novel carbon nanotube (CNT) composite films synthesized by a simple spray and vacuum-filtration method. The film containing 30 wt% single-walled CNTs demonstrates high electrical conductivity up to 20,000 S/m and excellent EMI shielding effectiveness 65 dB, with ∼130 μm in thicknesses and 0.011 g/cm 2 in areal density. The composite films are stiffer, stronger and more ductile than neat MWCNT film, i.e. 17.4 versus 3.3 MPa in tensile strength. Our films are sufficiently smooth, tough and flexible, which allow themselves to attach onto any complex curved surface. SWCNTs play an essential role in achieving such exceptional functional and mechanical performance; both SWCNTS and MWCNTS need to be well disentangled prior to the filtration. The composite films would have a wide range of engineering applications, i.e. production of conventional composite laminates due to their porous structure. [ABSTRACT FROM AUTHOR]

Plants can mitigate ambient particulate matter by cleaning the air, which is crucial to urban environments. A novel approach was presented to quantitatively characterize particulate matter deposited on urban tree foliage. This approach could accurately quantify the number, size, shape, and spatial distribution of particles with different diameters on leaves. Spatial distribution is represented by proximity, which measures the closeness of particles. We sampled three common broadleaf species and obtained images through field emission scanning electron microscopy. We conducted the object-based method to extract particles from images. We then used Fragstats to analyze the landscape characteristics of these particles in term of selected metrics. Results reveal that Salix matsudana is more efficient than Ailanthus altissima and Fraxinus chinensis in terms of the number and area of particles per unit area and the proportion of fine particulate matter. The shape complexity of the particles increases with their size. Among the three species, S. matsudana and A. altissima particles respectively yield the highest and lowest proximity. PM 1 in A. altissima and PM 10 in F. chinensis and S. matsudana show the highest proximity, which may influence subsequent particle retention. S. matsudana should be generally considered to collect additional small particles. Different species and particle sizes exhibit various proximities, which should be further examined to elucidate the underlying mechanism. [ABSTRACT FROM AUTHOR]

Kozlov & Klemola ( Journal of Ecology, 105, 2017: 000-000) argued that our conclusion about hemispheric asymmetries in herbivory is not supported after the replacement of data points extracted from Moles & Westoby ( Oikos, 90, 2000: 517-524.)., To re-evaluate the asymmetries in herbivory, we analysed the revised dataset according to Kozlov & Klemola's (2017) suggestion, as well as the dataset used in Kozlov et al. ( Global Ecology and Biogeography, 24, 2015: 1126-1135.)., All the analyses showed that herbivory decreased with latitude only in the Northern hemisphere, but in the Southern hemisphere, herbivory showed no relation to latitude. Model selection showed that in both datasets, hemisphere is a key determinant of herbivory, with Southern hemisphere having higher levels of herbivory than the Northern hemisphere., Synthesis. Based on currently available data collected from publications, we found evidence for hemispheric asymmetries in herbivory. This conclusion is unlikely to change even when the controversial data points are replaced. [ABSTRACT FROM AUTHOR]

The reconfigurable intelligent surface (RIS) fundamentally changes the existing anti‐jamming paradigm by reconstructing the wireless propagation environment. However, the existing RIS‐based anti‐jamming work mainly considers narrow‐band frequency‐flat fading channels. As an extension of existing work, the use of RIS to enhance the anti‐jamming capability of broadband orthogonal frequency division multiplexing (OFDM) system in frequency‐selective fading channels is first studied. In the multipath frequency‐selective fading channels, the anti‐jamming design needs to satisfy the channel gains of all signal paths with different delays. To this end, the authors propose a joint design scheme of active precoding at the transmitter and passive precoding at the RIS to attenuate the jamming signal and enhance the legitimate signal, and formulate the joint design objective to maximize the average rate of all subcarriers. An alternating optimization algorithm is developed to address this non‐convex problem due to the complex coupling of active and passive precoding. In detail, the active and passive precoding are solved by the Cauchy–Schwarz inequality and power water‐filling method and the alternating direction method of multipliers method assisted by multidimensional complex quadratic transform, respectively. Simulation results demonstrate that the proposed method can significantly improve the anti‐jamming communication performance of the OFDM system compared with the scheme without RIS. In addition, the impact of the number of RIS elements and deployment location on system performance is revealed. [ABSTRACT FROM AUTHOR]

Herbivory is well known to be a major selective pressure that affects plant communities, but the leaf traits that mediate variations in herbivory at the interspecific level remain controversial. We collected published data on background insect herbivory and leaf traits from a wide variety of species to test the hypothesis that species with intermediate leaf lifespans, lower fiber, and higher nutrient contents in leaves should have higher levels of herbivory. We found that at the interspecific level herbivory had a hump-shaped relationship with leaf lifespan and a positive relationship with leaf size. Surprisingly, our data show that nutritional traits have little relationship to herbivory. Our study provides new insights relevant to the recent debate on leaf trait-herbivory relationships. These findings are especially helpful in explaining the general patterns of herbivory detected on the global scale. [ABSTRACT FROM AUTHOR]

Road dust is one of the most common pollutants and causes a series of negative effects on plant physiology. Dust's impacts on plants can be regarded as a combination of load, composition and grain size impacts on plants; however, there is a lack of integrated dust effect studies involving these three aspects. In our study, Sophora japonica seedlings were artificially dusted with road dust collected from the road surface of Beijing so that we could study the impacts of this dust on nitrogen/carbon allocation, biomass allocation and photosynthetic pigments from the three aspects of composition, load and grain size. The results showed that the growth characteristics of S. japonica seedlings were mostly influenced by dust composition and load. Leaf N, root–shoot ratio and chlorophyll a/b were significantly affected by dust composition and load; leaf C/N, shoot biomass, total chlorophyll and carotenoid were significantly affected by dust load; stem N and stem C/N were significantly affected by dust composition; while the dust grain size alone did not affect any of the growth characteristics. Road dust did influence the growth characteristics more extensively than loam. Therefore, a higher dust load could increase the differences between road dust and loam treatments. The elements in dust are well correlated to the shoot N, shoot C/N, and root–shoot ratio of S. japonica seedlings. This knowledge could benefit the management of urban green spaces. [ABSTRACT FROM AUTHOR]

In the past, it was widely accepted that herbivory decreased with latitude. However, several empirical studies have failed to support this hypothesis, leading to strong debate. In addition to providing a quantitative assessment of the latitudinal gradient in herbivory, our study aims to provide new information about the role of climatic factors in shaping the latitudinal gradient in herbivory., Through the collection and analysis of published data on herbivory, we tested the latitudinal herbivory hypothesis ( LH hypothesis) and the relationship of temperature and precipitation to herbivory., Based on 1890 data points distributed world-wide from more than 1000 plant species, our results show that herbivory decreased with latitude and increased with temperature only in the Northern Hemisphere. In contrast, in the Southern Hemisphere, herbivory did not have a relationship with latitude and tended to decrease with temperature., Synthesis. This study shows the LH hypothesis is supported only in the Northern Hemisphere and highlights the importance of temperature in explaining the pattern of herbivory at the global scale. These possible hemispheric asymmetries in herbivory should not be overlooked in future studies. [ABSTRACT FROM AUTHOR]

Plant establishment is widely recognized as an effective way to prevent soil erosion in arid and semiarid ecosystems. Artemisia gmelinii , a pioneering species in many degraded ecosystems in China, is effective in improving soil properties and controlling runoff and soil loss, but mechanisms underlying soil improvement are not well understood. We therefore investigated how the presence and cover of A. gmelinii affect soil physico-chemical properties and soil microbial communities in differently sized soil aggregates in the rhizosphere and inter-plant soil in the Upper Minjiang River arid valley of China. We found that A. gmelinii presence significantly improved soil quality in terms of soil structure, water content, aggregate-associated carbon and nutrients, and soil microbial biomass and activities. Interestingly, also inter-plant soils were strongly influenced by adjacent-plant-cover, showing enhanced soil organic carbon, total carbon, nitrogen and phosphorus, and reduced soil bulk density and pH with increasing A. gmelinii cover in plots. In turn, the A. gmelinii -induced changes in inter-plant soil properties could explain a large part of the observed variation in microbial biomass, carbon and nitrogen. Importantly, effects of the presence and cover of A. gmelinii on soil properties were mostly specific for particular aggregate size classes. Specifically, A. gmelinii significantly increased P accumulation only in small macroaggregates (250–2000 μm) illustrating the importance of this aggregate class in terms of plant-mediated phosphorus accumulation, critical for P uptake in this P limited area. Our results thus indicate that A. gmelinii not only improves soil physical and microbial conditions in its rhizosphere but also in inter-plant soil, and that increasing A. gmelinii cover has the potential to reduce runoff and soil loss and to promote revegetation. [ABSTRACT FROM AUTHOR]

The role of forest plantations in biodiversity conservation has gained more attention in recent years. However, most work on evaluating the diversity of forest plantations focuses only on one spatial scale; thus, we examined the effects of sampling scale on diversity in forest plantations. We designed a hierarchical sampling strategy to collect data on woody species diversity in planted pine (Pinus tabuliformis Carr.), planted larch (Larix principis-rupprechtii Mayr.), and natural secondary deciduous broadleaf forests in a mountainous region of Beijing, China. Additive diversity partition analysis showed that, compared to natural forests, the planted pine forests had a different woody species diversity partitioning pattern at multi-scales (except the Simpson diversity in the regeneration layer), while the larch plantations did not show multi-scale diversity partitioning patterns that were obviously different from those in the natural secondary broadleaf forest. Compare to the natural secondary broadleaf forests, the effects of planted pine forests on woody species diversity are dependent on the sampling scale and layers selected for analysis. Diversity in the planted larch forest, however, was not significantly different from that in the natural forest for all diversity components at all sampling levels. Our work demonstrated that the species selected for afforestation and the sampling scales selected for data analysis alter the conclusions on the levels of diversity supported by plantations. We suggest that a wide range of scales should be considered in the evaluation of the role of forest plantations on biodiversity conservation. [ABSTRACT FROM AUTHOR]

The urban population and urbanized land in China have both increased markedly since the 1980s. Urban and suburban developments have grown at unprecedented rates with unknown consequences for ecosystem functions. In particular, the effect of rapid urbanization on the storage of soil carbon has not been studied extensively. In this study, we compared the soil carbon stocks of different land use types in Beijing Municipality. We collected 490 top-soil samples (top 20 cm) from urban and suburban sites within the Sixth Ring Road of Beijing, which cover approximately 2400 km, and the densities of soil organic carbon (SOC), soil inorganic carbon (SIC), and total carbon (TC) were analyzed to determine the spatial distribution of urban and suburban soil carbon characteristics across seven land use types. The results revealed significant differences in soil carbon densities among land use types. Additionally, urban soil had significantly higher SOC and SIC densities than suburban soil did, and suburban shelterbelts and productive plantations had lower SIC densities than the other land use types. The comparison of coefficients of variance (CVs) showed that carbon content of urban topsoil had a lower variability than that of suburban topsoil. Further findings revealed that soil carbon storage increased with built-up age. Urban soil built up for more than 20 years had higher densities of SOC, SIC and TC than both urban soil with less than 10 years and suburban soil. Correlation analyses indicated the existence of a significantly negative correlation between the SOC, SIC, and TC densities of urban soil and the distance to the urban core, and the distance variable alone explained 23.3% of the variation of SIC density and 13.8% of the variation of TC density. These results indicate that SOC and SIC accumulate in the urban topsoil under green space as a result of the conversion of agricultural land to urban land due to the urbanization in Beijing. [ABSTRACT FROM AUTHOR]

This paper prepares a flexible MXene/CNT film by layer‐by‐layer (LbL) self‐assembly process. Based on excellent conductivity and good compatibility with resin, MXene/CNT can be used for on‐line monitoring of large and complex liquid composite molding (LCM). In this paper, the MXene/CNT will be used as a novel micro‐nano sensor. The MXene/CNT sensor is embedded between the sandwich layers of the sandwich composite structure. The resistance information of the MXene/CNT sensor was collected by online monitoring system during LCM. The tube cross‐linked network's conductive model will be established to reveal the resistance response sensing mechanisms of MXene/CNT sensors and the response rules of resin flow states and resistance signals. Using the real‐time monitoring information collected by the MXene/CNT sensor, combined with Darcy's law, the comparison results of different permeability are obtained. The monitoring results show that polyvinyl chloride (PVC) interlayer significantly influences the resin flow trend and penetration of the core layer. Simultaneously, the interlayer's presence will also affect the resin flow trend and penetration of the lower layer of the PVC sandwich layer. The research results will provide theoretical guidance and technical support for designing process parameters and in situ real‐time monitoring of LCM in the engineering industry. [ABSTRACT FROM AUTHOR]

Plant roots play a crucial role in enhancing soil stability and protecting slopes during ecological restoration, particularly in mining areas where external-soil spray seeding is employed. However, the relationship between plant root pullout resistance and environmental factors on different types of slopes remains unclear. In this study, we investigated the interactions between the pullout resistance of a dominant species, Artemisia gmelinii , and environmental factors on three slope types (rocky, geotechnical, and soil) using multi-group structural equation modeling. Our findings reveal that the pullout resistance of plant roots was strongly influenced by various factors, including but not limited to biological factors such as plant height and biomass. It showed a positive correlation between soil silt content and soil nutrient levels. Notably, the pullout resistance on soil slopes was significantly higher than on rocky slopes. Furthermore, the impact of soil nutrients and texture on pullout resistance was more pronounced on geotechnical and soil slopes compared to rocky slopes. Multi-group structural equation modeling highlighted that among all environmental factors, slope gradient and underground biomass had the most significant influence on pullout resistance across all slope types. Specifically, slope gradient had a greater effect on soil slopes, whereas underground biomass played a more prominent role on rocky and geotechnical slopes. Overall, our study suggests that when implementing external-soil spray seeding in mining areas, it is crucial to consider the interplay between plant roots and environmental factors, including slope properties. This holistic approach is crucial for maximizing the effectiveness of plants in slope protection during eco-engineering projects. • The pullout resistance of soil slopes was greater than that of geotechnical and rocky slopes. • Slope gradient and underground biomass had great effects on pullout resistance for all slopes. • All slopes were greatly affected by the change in topographic factors, soil nutrients, and soil texture. [ABSTRACT FROM AUTHOR]

In general, it is accepted that gap formation significantly affects the placement of scatter‐hoarded seeds by small rodents, but the effects of different forest gap sizes on the seed‐eating and scatter‐hoarding behaviors of small rodents remain unclear. Thus, we examined the effects of a closed‐canopy forest, forest edge, and gaps with different sizes on the spatial dispersal of Quercus variabilis acorns and cache placement by small rodents using coded plastic tags in the Taihang Mountains, China. The seeds were removed rapidly, and there were significant differences in the seed‐eating and caching strategies between the stand types. We found that Q. variabilis acorns were usually eaten after being removed from the closed‐canopy forest and forest edges. By contrast, the Q. variabilis acorns in the forest gap stands were more likely to be scatter‐hoarded. The dispersal distances of Q. variabilis acorns were significantly longer in the forest gap plots compared with the closed canopy and forest edge plots. However, the proportion of scatter‐hoarded seeds did not increase significantly as the gap size increased. In small‐scale oak reforestation projects or research, creating small gaps to promote rodent‐mediated seed dispersal may effectively accelerate forest recovery and successional processes. [ABSTRACT FROM AUTHOR]

Repair of composite materials is an important cost savings for the aviation industry, and it is also very important to monitor the repaired structure. In this paper, a novel micro-nano sensor which is combined with Flexible Printed Circuit and Buckypaper (BP) sensor is introduced, and has the characteristics of multidirectional, real time and high sensitivity. These sensors are used to monitor the strain at different positions on the composite repair structure. The piezoresistive response of BP sensor is obtained and the main working mechanism of BP sensor is explained. Experiments show that this sensor can preliminarily judge the damage position and degree of the repaired structure, and monitor whether it reaches the strength limit. And it can judge the loading history of the structure. This ensures the safety of the repaired structure in the process of continuous service to a certain extent. [ABSTRACT FROM AUTHOR]

• The functions of CESI and LUI improved after reclaim in coalfields. • The CCD between LUI and CESI gradually improving over time. • The joint influence of natural and human factors on CCD. The land use and cover changes (LUCC) caused by strong coal-mining activities and ecological restoration practices have seriously interfered with the ecosystem services (ESs) in the mining area. However, little attention has been paid to how to explore and improve the coordinated relationship between LUCC and ESs in mining areas. This study investigated the crucial relationship between ESs and land use intensity (LUI) in coal-mining areas, emphasizing the significance of understanding this interdependence for balanced human–land system development. Employing a coupling coordination degree (CCD) model, this research examined the evolving relationship across various reclamation stages of coalfields in Shanxi, China, spanning from 1986 to 2020. Additionally, stepwise and geographically weighted regressions were utilized to investigate the primary factors influencing CCD and their respective impacts. Notably, the comprehensive ecosystem service index (CESI) exhibited an upward trend between 1986 and 2020, whereas the LUI initially increased and subsequently declined during the reclamation stages. Moreover, the CCD between the LUI and CESI gradually evolved from mildly maladjusted to reluctant coordination throughout the various reclamation stages, gradually improved over time. Geographically, the region exhibited a coordinated level gradually expanded. Precipitation, slope, coal mining intensity, and industrial output emerged as primary CCD influencers. Coal mining intensity exerted negative impacts, whereas the impact of industrial output was minimal. Based on our findings, we recommend the timely and judicious reclamation of coalfields, taking into consideration the land's bearing capacity. [ABSTRACT FROM AUTHOR]

In this work, graphene aerogels (GAs) with three-dimensional interconnected networks were prepared by chemical reduction and self-assembly of graphene oxide sheets. After microwave treatment, obtained microwave reduced graphene aerogels (MRGAs) were used in the preparation of bismaleimide (BMI) composites. The results show that the microwave treatment significantly enhanced the quality of GAs, and the three-dimensional networks in the GAs were well retained. Moreover, the MRGAs were highly efficient in endowing BMI with high electrical conductivity and excellent electromagnetic interference shielding effectiveness (EMI SE). The conductivity of MRGA/BMI composites was 42–68% higher than that of GA/BMI composites. When the filler content is 1.6 wt.%, the EMI SE of MRGA/BMI composite was 32.3% higher than that of GA/BMI composite in the X band. A facile approach to enhance the quality and conductivity of graphene aerogels (GAs) by microwave irradiation was reported. The obtained microwave reduced graphene aerogels (MRGAs) endowed the MRGA/bismaleimide (BMI) composites with high conductivity and electromagnetic interference (EMI) shielding performance. Moreover, the MRGA/BMI composites showed an EMI shielding mechanism dominated by absorption. [ABSTRACT FROM AUTHOR]

The properties of polymer nanocomposites depend greatly on the dispersion of nanoparticles in the polymer matrix. To improve the dispersion of single-walled carbon nanotubes (SWCNTs) in bismaleimide (BMI) resin, this paper developed a feasible method for non-covalent modification of SWCNTs by using polyvinylpyrrolidone (PVP). Moreover, the effect of functionalized SWCNTs on the properties of BMI composites was systematically investigated. The results showed that it was very effective for PVP as a surface modifier for the dispersion of SWCNTs in BMI resin. As a consequence, the electrical conductivity and mechanical properties of the SWCNT/BMI composites were all improved by the incorporation of SWCNTs at a low content. The study also presented that the heat resistance and thermal stability of SWCNT/BMI composites were simultaneously enhanced. [Display omitted] • A simple and feasible dispersion method for SWCNTs in BMI resin was developed. • The threshold percolation of SWCNTs/BMI composites was less than 0.01 wt%. • The mechanical properties of the composites increased substantially with a very low SWCNTs content. [ABSTRACT FROM AUTHOR]

In this paper, we report the fabrication of a high-sensitivity strain sensor fabricated using graphene platelets (GnPs) and multi-walled carbon nanotubes (MWCNTs) for monitoring joint-bending movement. The optimized ultrasonic time and the ball mill-mixing process make the GnPs disperse evenly in the MWCNTs. The strain sensor made up of the GnP/MWCNT mixture (30 wt% GnPs loading) is fabricated by a spray-method and its conductivity is up to 104 S/m. The as-prepared GnP/MWCNT sensor exhibits relatively high tensile strength of 5.4 MPa, sensing range of 7.5%, gauge factor of 181.36, linearity of 99.545%, and great bending reproducibility over 5000 cycles. These remarkable features endow our sensing devices to monitor joint bending in human health monitoring, e.g., elbow, finger and wrist bending. The results demonstrate that our flexible GnP/MWCNT sensor shows promising applications prospects in smart wearable device monitoring human health. [ABSTRACT FROM AUTHOR]

As the portable device hardware has been increasing at a noticeable rate, ultrathin flexible materials with the combination of high thermal conductivity and excellent electromagnetic interference (EMI) shielding performance are urgently needed. Here, we fabricated ethylene propylene diene monomer rubber with different loading graphene nanoplatelets (GnPs/EPDM) by a cost-efficient approach, which combines mixing, ultrasonication and compression. Further investigation demonstrates that the 8 wt.% GnPs/EPDM with only 0.3 mm in thickness shows excellent electrical conductivity (28.3 S/m), thermal conductivity (0.79 W/m K) and good mechanical properties. Besides, the 8 wt.% GnPs/EPDM exhibits an EMI shielding effectiveness (SE) up to 33 dB in the X-band (8.2–12.4 GHz) and 35 dB in the Ku-band (12.4–18 GHz), superior to most of the reported rubber matrix. Additionally, the GnPs/EPDM shows excellent flexibility and stability with 95% and 94% retention of EMI SE even after repeated bending for 5000 times and corrosion (under 5% NaCl environment) for a week. Our flexible EMI shielding material will benefit the fast-growing next-generation commercial portable flexible electrons. The GnPs/EPDM was fabricated by a cost-efficient approach, which combines mixing, ultrasonication and compression. The prepared 8 wt.% GnPs/EPDM shows excellent electrical conductivity (28.3 S/m), thermal conductivity (0.79 W/m.K) and good mechanical properties. Besides, the SET reaches up to 33 dB in the X-band (8.2–12.4 GHz) and 35 dB in the Ku-band (12.4–18 GHz) with the thickness of only 0.3 mm. The flexible EMI shielding material will benefit the fast growing next-generation commercial portable flexible electrons. [ABSTRACT FROM AUTHOR]

Highlights • This paper proposes a new GNP/MWCNT sensor, because of its unique mesoporous structure, the GNP/MWCNT film has good compatibility with the composite. • During the manufacturing process, the sensor can effectively capture the change of the resin phase, which is characterized by resistance change. As the resin changes from a rubbery state to flowing liquid state, the resin infiltration sensor changes the conductive structure. It causes the resistance increase. When resin cross-links, the matrix contraction leads to the electrical structure recovery and resistance drop. Once the resin cured basically, the resistance rises slowly due to its negative temperature coefficient. • With a standard curing system, the gel point was demonstrated in the curve of the real-time resistance change of the sensor. Compared with DMA results, results are basically same. However, DMA is laboratory method under certain conditions. It requires specific samples that are small size and/or lightweight. The GNP/MWCNT film sensor can monitor gel points in different locations and thicknesses in real time. Therefore, this method readily be applied to the in-situ monitoring of composite curing on the industrial scale and results are more accurate. Abstract In this study, we developed a film sensor composed of multi-walled carbon nanotubes (MWCNTs) and graphene nanoplates (GNPs) via a simple mixing and spray-vacuum filtration. This highly flexible and sensitive GNP/ MWCNT film sensor can be embedded into polymer composite to in situ monitor the resin phase changes and gel point during the composite manufacturing process. The resistance of the GNP/MWCNT film sensor was obtained using two-terminals method by Fluke 2638 A, and the resistance changes could be related to phase changes of the resin matrix. Dynamic mechanical analysis (DMA) was performed to obtain the gel point of the composite as a baseline to compare with the GNP/MWCNT film sensor output. Experimental results show that the GNP/MWCNT film sensor embedded in the composite laminates can effectively capture the change of the resin phase, which is characterized by resistance. As the resin changed from the rubber state to the flow state, the resistance increased from 2.5 × 10−3 to 1.04. When the resin was cross-linked, the resistance dropped from 1.04 to 0.88. Once the resin is substantially cured, the resistance rises from 0.88 to 0.97 slowly. GNP / MWCNT films have a good ability to respond to changes in the resin state. The gel point of resin obtained from the GNP/ MWCNT film sensor is 134℃, which is consistent with 137℃ from the DMA results. The accurate gel point can optimize the curing system and improve the quality of composite products. The GNP/MWCNT film sensor has great potential to establish and optimize manufacturing processes and to improve the cure quality of fibre-based resin composites. [ABSTRACT FROM AUTHOR]

Highlights • Ultrafine and fine particles are more sensitive to magnification than big particles. • The percentage of leaf area covered of particles is a relatively stable index. • Magnifications 1000× and 2000× are more comparable than other magnifications. Abstract The metrics used to quantify the particles on the leaf surface can serve as indicators for the quality of the atmospheric environment and is employed to evaluate the ecosystem services that plants can provide. Magnification of an SEM image may affect the recognition of particles in various aspects, yet little research has examined the impact. In this study, images were obtained at magnifications of 500×, 1000×, 2000×, and 5000× for a widely planted vegetation fence species in Beijing: Euonymus japonicas. Particle amount per leaf area increased as magnification increased; the percentage of the leaf area covered by particles was a relatively stable index across magnifications at around 7% except for the magnification 2000× which was around 15%; and the weight of particles per leaf area was unstable over all magnifications. The mean area of each particle decreased from 5.68 μm2 at magnification 500× to 0.20 at magnification 5000×, and shape complexity increased as magnification increased from 1.29 at magnification 500× to 1.50 at magnification 5000×. Particles with a diameter of less than 2.5 μm are more sensitive to scale than particles with a diameter greater than 2.5 μm of judged by the differences of the characteristics, diameter, area and shape index, of particles with different diameter ranges over four magnifications. Regarding the percentage characteristic, the percentage of particles with a diameter smaller than 1 μm increased as the magnification increased and accounted for 46% at magnification 500× and 96% at magnification 5000×. The percentage of particles with an area smaller than 1 μm2 also increased as the magnification increased accounting for 56% at magnification 500× and 99% at magnification 5000×. Particles with shape index between 1–1.5 accounted for most of the particles across all four magnifications of which the percentage was 0.66–0.80. Therefore, when comparing the results from different magnifications, three factors should be considered carefully: magnification, quantification index, and particle size range. The revealed relationship of the factors can facilitate the understanding of the metrics as indicators for atmospheric environments and vegetation as a sink for atmospheric particles to improve the urban environment. [ABSTRACT FROM AUTHOR]

Elevational richness patterns and underlying environmental correlates have contributed greatly to a range of general theories of biodiversity. However, the mechanisms underlying elevational abundance and biomass patterns across several trophic levels in belowground food webs remain largely unknown. In this study, we aimed to disentangle the relationships between the elevational patterns of different trophic levels of litter invertebrates and their underlying environmental correlates for two contrasting ecosystems separated by the treeline. We sampled 119 plots from 1020 to 1770 asl in forest and 21 plots from 1790 to 2280 asl in meadow on Dongling Mountain, northwest of Beijing, China. Four functional guilds were divided based on feeding regime: omnivores, herbivores, predators, and detritivores. We used eigenvector-based spatial filters to account for spatial autocorrelation and multi-model selection to determine the best environmental correlates for the community attributes of the different feeding guilds. The results showed that the richness, abundance and biomass of omnivores declined with increasing elevation in the meadow, whereas there was a hump-shaped richness pattern for detritivores. The richness and abundance of different feeding guilds were positively correlated in the forest, while not in the meadow. In the forest, the variances of richness in omnivores, predators, and detritivores were mostly correlated with litter thickness, with omnivores being best explained by mean annual temperature in the meadow. In conclusion, hump-shaped elevational richness, abundance and biomass patterns driven by the forest gradient below the treeline existed in all feeding guilds of litter invertebrates. Climate replaced productivity as the primary factor that drove the richness patterns of omnivores above the treeline, whereas heterogeneity replaced climate for herbivores. Our results highlight that the correlated elevational richness, abundance, and biomass patterns of feeding guilds are ecosystem-dependent and that the underlying environmental correlates shifted at the treeline for most feeding guilds. [ABSTRACT FROM AUTHOR]

The graphene platelets (GnPs)/epoxy flexible sensor with controllable sensitivity and linearity can be used to monitor the deformation and damage of composite structures. The sensitivity and linearity can be regulated by dispersing different content of GnPs in epoxy and the dispersion was better improved by optimizing ultrasonic time and the ball mill mixing process. The GnPs/epoxy mixture exhibited relatively low percolation threshold of 0.76 vol %. In this paper, GnPs/epoxy mixtures with GnPs loading of 0.84 vol.%, 1.05 vol % and 1.58 vol % were selected as damage detecting and strain sensor, and the characteristics of sensors were demonstrated via various mechanical tests. The monotonic tensile results suggest that there are three different linear change sensing stages, (1–0.2%), (0.2%–0.6%) and (0.6%–1.2%), the linear growth of the electrical response is softened while the linear tendency is enhanced due to increasing GnPs content, and it exhibits relatively high gauge factor of 11.81, 15.25 and 22.54 for 0.84 vol %, 3.63, 8.13, 11.46 for 1.05 vol % and 2.53, 3.77, 4.69 for 1.58 vol % in different sensing stages respectively. The sensor of 0.84 vol % is more reversibility than 1.05 vol % upon cyclic loading-unloading test. The GnPs/epoxy sensor show promising applications for the damage monitoring of structural composite in the field of aerospace. [ABSTRACT FROM AUTHOR]

In this study, we developed a buckypaper (BP) composed of a mono-dispersion of multi-walled carbon nanotubes (MWCNTs) via a spray-vacuum filtration method. This highly flexible and sensitive carbon nanotube buckypaper (MWNCTs-BP) sensor can be integrated into complex curved surfaces and at critical stress areas to monitor the dynamic manufacturing process of fibre-reinforced composites in real time. A dynamic heating cure cycle and two revised cure cycles were designed to study the response of the resistance of the buckypaper to resin phase changes during the composite manufacturing process. Dynamic mechanical analysis (DMA) was performed to obtain the cure behaviour of a glass fibre/epoxy composite as a baseline to compare with the MWCNTs-BP sensor output. The experimental results show that the cure behaviour of epoxy/glass composites can be effectively monitored by the relative resistance change of the BP sensor embedded in the composite laminate. The MWCNTs-BP shows that the lowest viscosity point and gelation point of the composite resin were at 78 °C and 125 °C during the dynamic heating cure cycle, which is consistent with the DMA results. The lowest viscosity and gelation point can also be accurately obtained during the revised cure cycles. The MWCNTs-BP system has great potential as a sensor to establish and optimize manufacturing processes and to improve the cure quality of fibre-based resin composites. [ABSTRACT FROM AUTHOR]

The graphene platelets (GnPs)/epoxy flexible sensor with high sensitivity and linear can be used to monitor the deformation and damage in structural composites. The dispersion of GnPs in an epoxy matrix was better improved by optimizing ultrasonic time and using the ball mill mixing process. The GnPs/epoxy mixture exhibited relatively low percolation threshold of 0.76 vol.% and its analysis model was analyzed. In this paper, GnPs/epoxy mixture with GnPs loading of 1.00 vol.% was selected as damage detecting and strain sensor, and the characteristics of sensor was demonstrated via various mechanical tests. The monotonic tensile results suggested that there are two different linear change sensing stages, (0–5000 με ) and (5000–16700 με ), and it exhibits relatively high gauge factor (GF) of 6.5 and 11.6 in different sensing stages. The linear relationship and sensitivity were recoverable and stable upon loading and unloading tensile test. And the gauge factors upon loading and unloading test agree with the GF in monotonic tensile test. The GnPs/epoxy flexible sensor show promising applications for the damage monitoring of structural composite in the field of aerospace. [ABSTRACT FROM AUTHOR]

Ecologists and biogeographers have long been interested in the underlying mechanisms shaping the elevational patterns of biodiversity. However, most of these studies have been conducted aboveground. Although they deliver key ecosystem functions and services, the elevational diversity and biomass patterns of soil invertebrates, including a wide range of taxa, have been severely understudied, especially at treeline. To address this critical gap, we identified richness, abundance, and biomass patterns of soil invertebrates across an elevational gradient under below-treeline forest (from 1020 to 1770 asl) and above-treeline meadow (from 1790 to 2280 asl), respectively. We aimed to (1) identify the elevational patterns of richness, abundance, and biomass in soil invertebrates across the treeline; and (2) test whether these patterns break and the underlying mechanisms shift at the treeline. We found that both the diversity and biomass of litter-dwelling invertebrates showed hump-shaped patterns below the treeline and monotonically decreasing patterns above the treeline, respectively. Richness association of litter-dwelling invertebrates and herbaceous plants shifted from negative to positive at the treeline. For the soil-dwelling invertebrates, no elevational trends were detected in forest while the diversity decreased monotonically with elevation in meadow. In contrast to basal area and litter thickness in forest, temperature was most strongly related to the diversity of litter-dwelling invertebrates in meadow. We showed the breaks in elevational diversity patterns of soil invertebrates at the treeline, while elevational patterns of biomass did not change. Microclimate replaced productivity as the most important factor driving the diversity patterns of litter-dwelling invertebrates across the treeline with vegetation shifts induced by increasing elevation. [ABSTRACT FROM AUTHOR]

Interface is an important microstructure for advanced polymer-matrix composite. The composite interface is the bridge and the link for stress transferring between the fiber and the matrix resin. In this work, oxygen plasma treatment was used for modification of aramid fiber surface. The effects of plasma treatment power on interlaminar shear strength of composite were evaluated by short-beam shear test. The morphologies of both the aramid fiber surface and its composite interface fracture were observed by SEM. The chemical structure and surface chemical composition of the plasma-treated and separated fibers were analyzed by Fourier transform infrared (FTIR) and XPS, respectively. The results showed that the interlaminar shear strength of composite was enhanced by 33% with plasma treatment power of 200 W. The FTIR and XPS results indicated that the active functional groups were introduced onto the aramid fiber surface by plasma treatment forming chemical bonds with the poly(phthalazinone ether sulfone ketone) resin. The SEM results proved that the aramid fiber surface was roughened by plasma treatment enhancing the mechanical bond with the poly(phthalazinone ether sulfone ketone) resin. The composite rupture occurred from the composite interface to the fiber or the matrix resin. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

• The functions of ESs improved after reclaim in coalfields. • The interaction of natural and human factors has a great impact on ESs. • The contribution rate of natural factors is greater than that of human factors. Coal contributes considerably to economic and social development. Its economic benefits have been in focus, whereas the ecosystem services (ESs) that coalfields provide have been largely neglected, and the research on driving force is not deep enough. We estimated soil conservation level, water yield, and habitat quality using the Integrated Valuation of Ecosystem Services and Tradeoffs model; evaluated carbon sequestration using the Carnegie-Ames-Stanford approach; and quantified windbreak and sand fixation using the revised wind erosion equation, based on multi-source data from coalfields in Shanxi Province, China, from 1986 to 2020. Additionally, we identified the dominant effects of the single drivers, and their interactions on ESs, using the geographical detector model. Thereafter, the relative contribution of natural factors and anthropogenic disturbance to ESs was quantified. The results showed that (1) The functions of soil conservation, water yield, carbon sequestration, and windbreak and sand fixation greatly improved, whereas the habitat quality decreased slightly from 1986 to 2020. (2) Changes in soil conservation were mainly influenced by temperature, precipitation, digital elevation model (DEM), population size, construction land area, coal mining intensity, industrial output, and land use intensity. Variations in water yield were mainly governed by temperature, precipitation, DEM, population size, construction land area, industrial output, and coal mining intensity. Variations in carbon sequestration were mainly affected by temperature, precipitation, slope, and coal mining intensity. Changes in windbreak and sand fixation services were mainly influenced by temperature, precipitation, slope, DEM, construction land area, coal mining intensity, industrial output, and land use intensity. Changes in habitat quality were mainly influenced by precipitation, slope, DEM, population size, coal mining intensity, industrial output, and land use intensity. (3) The impacts of the interactions between natural and human factors on ESs were more remarkable than those of a single factor. Furthermore, the contribution of natural factors to changes in ESs was dominant, whereas that of human factors was relatively small. Efficient coordination between natural and human forces, as well as ESs, is essential for the long-term evolution of the coalfield ecosystem. Such efforts will provide a scientific foundation for developing land reclamation and ecological restoration. [ABSTRACT FROM AUTHOR]