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In previous practice, the differential strain analysis (DSA) method, relied upon for estimating vertical principal stress to resolve geological stress, has shown limitations in reliability. Drawing upon observations of the Kaiser effect in rock samples, we introduce the Kaiser-differential strain analysis (Kaiser-DSA) method, amalgamating the Kaiser effect with the DSA method to assess in-situ stress differentials. Comparative evaluation with the stress relief method reveals that the Kaiser-DSA method demonstrates minimal relative error and generally consistent orientation of the maximum horizontal principal stress. Utilizing the findings from in-situ stress testing, this investigation scrutinizes the distribution patterns of in-situ stress in Yaojie Mining Area and investigates the causative factors contributing to the prevailing in-situ stress field. The study elucidates that Yaojie Mining Area is subject to the influence of compressive tectonic stress fields, resulting in elevated residual stress. Influenced by the Qinghai-Tibet thrust nappe action and the clockwise shear action of the F19 fault, the geostress field in this region predominantly manifests a strike-slip stress state typified by σH>σv>σh. Furthermore, the heightened differential stress within this locale exacerbates deformation and damage to the surrounding rock mass during mining activities, thereby exacerbating the frequency of dynamic disaster events.

Multistage hydraulic fracturing of horizontal wells (MFHW) is a promising technology for controlling coal burst caused by thick and hard roofs in China. However, challenges remain regarding the MFHW control mechanism of coal burst and assessment of the associated fracturing effects. In this study, these challenges were investigated through numerical modelling and field applications, based on the actual operating parameters of MFHW for hard roofs in a Chinese coal mine. A damage parameter (D) is proposed to assess the degree of hydraulic fracturing in the roof. The mechanisms and effects of MFHW for controlling coal burst are analyzed using microseismic (MS) data and front-abutment stress distribution. Results show that the degree of fracturing can be categorized into lightly-fractured (D≤0.3), moderately fractured (0.3

Abstract Background This study investigated the relaxation effect of PGE2 on the ureter and its role in promoting calculi expulsion following calculi development. Methods By using immunofluorescence and Western blot, we were able to locate EP receptors in the ureter. In vitro experiments assessed the impact of PGE2, receptor antagonists, and agonists on ureteral relaxation rate. We constructed a model of ureteral calculi with flowable resin and collected ureteral tissue from postoperative side of the ureter after obstruction surgery. Western blot analysis was used to determine the protein expression levels of EP receptors and the PGE2 terminal synthase mPGES-1. Additionally, PGE2 was added to smooth muscle cells to observe downstream cAMP and PKA changes. Results The expression of EP2 and EP4 proteins in ureteral smooth muscle was verified by Western blot analysis. According to immunofluorescence, EP2 was primarily found on the cell membrane, while EP4 was found in the nucleus. In vitro, PGE2 induced concentration-dependent ureteral relaxation. Maximum diastolic rate was 70.94 ± 4.57% at a concentration of 30µM. EP2 antagonists hindered this effect, while EP4 antagonists did not. Obstructed ureters exhibited elevated mPGES-1 and EP2 protein expression (P

With the increase in the depth and intensity of coal mining, some coal mines encounter the dual disaster threat of gas outburst and rockburst, and the composite gas-rockburst disaster has become a scientific and engineering problem that deserves more attention, and the distribution of abutment stress is of great significance for revealing the mechanism of composite dynamic disasters. This paper focuses on the influence of gas pressure on the abutment stress, establishes a theoretical model of a circular roadway and obtains the influence of gas pressure changes on the tangential stress and the radius of the plastic zone. The influence characteristic of gas pressure on the front abutment of a longwall working face is simulated based on the typical engineering geological conditions of an outburst-rockburst mine. The results show that as the gas pressure decreases, the tangential stress around the roadway increases, and the radius of the plastic zone decreases, meaning that the peak tangential stress is closer to the roadway. The peak abutment stress is negatively correlated with the gas pressure, while the distance of the peak from working face is opposite, both showing a quadratic relationship. On-site monitoring shows that as gas extraction proceeds, the frequency of mining-induced tremors increases significantly. When there is a sharp upward trend of the mining-induced tremors along with the continuous decrease of gas pressure, the risk of rockburst is high. A gas-rockburst coordination prevention and control technology system is established in Haishiwan Coal Mine based on the relationship of gas pressure changes and rockburst danger. During the gas control process, the gas pressure-microseismicity frequency is used to predict the rockburst risk and optimize the starting position and strength of destress engineering to achieve collaborative prevention and control of outburst-rockburst.

The roof breaking movement of steeply inclined and ultra-thick coal seam mining is complex, and the evolution law of stress and energy is special. Under the influence of deep ‘three highs and one disturbance’, the prevention and control of rock burst is not optimistic. Based on the experience of rock burst prevention and control in horizontal section mining of steeply inclined and ultra-thick coal seam after the rock burst accident in a mine in 2016, the experience of rock burst prevention and control in steeply inclined and ultra-thick coal seam in the past seven years is introduced in detail from the mechanism of rock burst in horizontal section mining of steeply inclined and ultra-thick coal seam, the comprehensive prevention and control of gas outburst and rock burst and the management of rock burst. In terms of the mechanism of rock burst, the inclined cantilever beam model of roof strata is established, the evolution process of fracture instability of roof and floor overburden structure is revealed, and the ‘clamping theory’ of rock burst in steeply inclined and ultra-thick coal seam is put forward. In terms of comprehensive prevention and control of gas outburst and rock burst, based on the theory of strength weakening and rock burst reduction of rock burst disaster control and disaster relief technology, combined with the original outburst prevention measures system, this paper puts forward the measures that can prevent and benefit the outburst prevention, forms a mine gas/carbon dioxide outburst/rock burst ‘integrated control’ technology system, and establishes a rock burst prevention and control system suitable for the horizontal section mining of steeply inclined thick coal seam in a mine. The intensity of gas outburst prevention and control is verified by the amount of drilling cuttings and the value of gas absorption and desorption. At the same time, the distribution of microseismic events and the total frequency and energy of each energy level are compared in the working face with pressure relief measures. The effectiveness of the control effect of the pressure relief scheme is demonstrated. In terms of rock burst management, a “six-in-one” comprehensive prevention and control framework has been formed, including prediction and evaluation, monitoring and early warning, treatment and prevention, effect test, safety protection and education and training. Based on the “Coal Mine Safety Regulations” and “Detailed Rules for Prevention and Control of Coal Mine Rock Burst” and other provisions, the Q/YJMD-FC 0104-2022“Yaojie Coal and Electricity Group Co., Ltd. Coal Mine Rock Burst Prevention and Control Part IV: Technical Specification for Prevention and Control of Rock Burst” was formulated.

AbstractThe magnitude and direction of the in-situ stress field significantly influence the Geodynamic disaster. Taking the Gaojiapu Coal Mine in the northwest Binchang mining area as the study area, the distribution law of the in-situ stress field and its relationship with microseismic events were analyzed and discussed through field geological investigation, in-situ measurement, and numerical simulation. The results show that: (1) The Maximum horizontal principal stress (MaxHPS) is mainly concentrated in the turning end of the fold, the axis of the syncline, the undulation end of the anticline, the footwall of the fault, and the two ends of the fault. (2) The MaxHPS in the footwall area of the fault is greater than that in the hanging wall area. (3) The MaxHPS at the axial part of the syncline is greater than that at the wing part, and the MaxHPS at the wing part is greater than that at the anticline. (4) In areas with high MaxHPS and Lateral pressure coefficient (LPC), the frequency of high-energy microseismic events is high. (5) The 105J high-energy microseismic events more easily occur in areas with MaxHPS greater than 38 MPa and LPC greater than 1.50.

Atmospheric methane is one of the major greenhouse gases and has a great impact on climate change. To obtain the polluted levels of atmospheric methane in the ground-level range, this study used satellite observations and vertical profile features derived by atmospheric chemistry model to estimate the ground methane concentrations in first. Then, the improved daily ground-level atmospheric methane concentration dataset with full spatial coverage (100%) and 5-km resolution in mainland China from 2019 to 2021 were retrieved by station-based observations and gaussian regression model. The overall estimated deviation between the estimated ground methane concentrations and the WDCGG station-based measurements is less than 10 ppbv. The R by ten-fold cross-validation is 0.93, and the R2 is 0.87. The distribution of the ground-level methane concentrations in the Chinese region is characterized by high in the east and south, and low in the west and north. On the time scale, ground-level methane concentration in the Chinese region is higher in winter and lower in summer. Meanwhile, the spatial and temporal distribution and changes of ground-level methane in local areas have been analyzed using Shandong Province as an example. The results have a potential to detect changes in the distribution of methane concentration.

Abstract The assessment of Coal burst risk (CBR) is the premise of bump disaster prevention and control. It is the implementation criterion to guide various rock burst prevention and control measures. The existing static prediction and evaluation methods for CBR cannot be effectively combined with the results of underground dynamic monitoring. This study proposed a mining-induced seismicity information quantification method based on the fractal theory. Deep learning methods were used to construct a deep learning framework of coal burst risk (DLFR) based on the fractal dimension of microseismic information. Gray correlation analysis (GRA), information gain ratio (IGR), and Pearson correlation coefficient are used to screen and compare factors. Statistical evaluation indicators such as macro-F1, accuracy rate, and fitness curve were used to evaluate model performance. Taking the Gaojiapu coal mine as a case study, the performance of deep learning models such as BP Neural Network (BP), Support Vector Machine (SVM) and its optimized model based on particle swarm optimization (PSO) algorithm under this framework is discussed. The research results' reliability and validity are verified by comparing the predicted results with the actual results. The research results show that the prediction results of CBR in DLFR are consistent with the actual results, and the model is reliable and effective. The mining-induced seismicity quantification can solve the problem of insufficient training samples for the CBR. With this, different pressure relief measures can be formulated based on the results of the CBR predictions to achieve "graded" precise prevention and control.

The recovery of submerged macrophytes is crucial for lake restoration. However, Myriophyllum spicatum usually shows an overgrowth and inhibits the growth of Vallisneria denseserrulata via light shading in many restored shallow lakes after the plant transplantation. So far, harvesting M. spicatum is the primary method to alleviate these shading effects in post-restoration lakes. Nevertheless, the effects of harvesting on the growth of V. denseserrulata and water quality are poorly elaborated. In this study, we conducted a mesocosm experiment, including both monoculture and polyculture groups, to investigate the response of V. denseserrulata growth, light climate, and nutrient concentrations in the water with M. spicatum harvesting. Moreover, the growth and morphology of M. spicatum were also examined. We hypothesized that M. spicatum harvesting would enhance the growth of V. denseserrulata and improve both the light climate and water quality. Our results showed that harvesting M. spicatum in the polyculture mesocosms substantially enhanced the relative growth rate (RGR) of V. denseserrulata compared to the non-harvesting controls. Moreover, harvesting M. spicatum reduced the light attenuation coefficient at 30 cm depth; however, the concentrations of chlorophyll-a, total nitrogen, and total phosphorus did not change significantly. As for M. spicatum, harvesting inhibited the growth of main stem and root but did not significantly affect the cumulative weight and RGR of M. spicatum. In contrast, the presence of V. denseserrulata decreased cumulative weight and RGR while promoting the root parameters of M. spicatum. Our findings imply that harvesting overgrowth nuisance submerged macrophyte species (e.g., M. spicatum) can improve the light climate and reduce its root growth, thereby enhancing the growth of target macrophyte species like V. denseserrulata without changes in the water quality which provides valuable insights for post-restoration lake management.

Flexible electronics have revolutionized the field by overcoming the rigid limitations of traditional devices, offering superior flexibility and adaptability. Conductive ink performance is crucial, directly impacting the stability of flexible electronics. While metal filler-based inks exhibit excellent conductivity, they often lack mechanical stability. To address this challenge, we present a novel conductive ink utilizing a ternary composite filler system: liquid metal and two micron-sized silver morphologies (particles and flakes). We systematically investigated the influence of filler type, mass ratio, and sintering process parameters on the composite ink’s conductivity and mechanical stability. Our results demonstrate that flexible wires fabricated with the liquid metal/micron silver particle/micron silver flake composite filler exhibit remarkable conductivity and exceptional bending stability. Interestingly, increasing the liquid metal content results in a trade-off, compromising conductivity while enhancing mechanical performance. After enduring 5000 bending cycles, the resistance change in wires formulated with a 4:1 mass ratio of micron silver particles to flakes is only half that of wires with a 1:1 ratio. This study further investigates the mechanism governing resistance variations during flexible wire bending. Additionally, we observed a positive correlation between sintering temperature and pressure with the conductivity of flexible wires. The significance of the sintering parameters on conductivity follows a descending order: sintering temperature, sintering pressure, and sintering time. Finally, we demonstrate the practical application of this technology by integrating the composite ink-based flexible wires with conductive polymer-based strain sensors. This combination successfully achieved the detection of human movements, including finger and wrist bending.

Abstract 2D materials are considered as potential candidates for the next generation of optoelectronic materials. However, their optical absorption is typically weak due to thickness limitations, greatly restricting the photodetection capabilities of devices. To enhance the photoelectric gain of 2D materials or devices and improve detection sensitivity, various modulation methods such as strain, electric field, and magnetic field are commonly introduced. Among them, surface acoustic wave (SAW) represents a unique and effective modulation approach. In this study, photodetectors are fabricated based on few‐layer MoS2 on a SAW delay line on a LiTaO3 substrate. The interaction between SAW and MoS2 successfully manipulates the optoelectronic performance of the MoS2‐based devices. Under the influence of SAW, the dark current of the devices is significantly reduced by more than two orders of magnitude, while the photocurrent remains almost unchanged, resulting in excellent photoresponse performance. The devices provide a promising pathway for high‐performance optoelectronic applications and reveal a new possibility for acoustic devices in optoelectronics.

Abstract In this work, we develop a new type of mesoporous 2D N, B, and P codoped carbon network (NBP-CNW) arranged into high-order 3D nanotube arrays (NTAs), which are wrapped onto a flexible carbon fiber microelectrode, and this microelectrode is employed as a high-performance carbon-based nanocatalyst for electrochemical biosensing. The NBP-CNW-NTAs synthesized by a facile, controllable, ecofriendly and sustainable template strategy using ionic liquids as precursors possess a high structural stability, large surface area, abundant active sites, and effective charge transport pathways, which dramatically improve their electrocatalytic activity and durability in the redox reaction of cancer biomarker H2O2. Benefiting from these unique structural merits, superb electrochemical activity and good biocompatibility, the NBP-CNW-NTAs-modified microelectrode demonstrates excellent sensing performance toward H2O2 and is embedded in a homemade microfluidic electrochemical biosensor chip for the real-time tracking of H2O2 secreted from different live cancer cells with or without radiotherapy treatment, which provides a new strategy for distinguishing the types of cancer cells and evaluating the radiotherapeutic efficacy of cancer cells. Furthermore, the functional microelectrode is integrated into an implantable probe for the in situ detection of surgically resected human specimens to distinguish cancer tissues from normal tissues. These will be of vital significance for cancer diagnoses and therapy in clinical practice.

Upper protective layer (UPL) mining is extensively utilised as a pressure relief strategy to prevent outbursts and coal bursts. However, when the excavation height of the protected layer is substantial, the depressurisation efficacy of the protective layer may be diminished. This paper takes the Haishiwan coal mine in China as a case study and explores the stress evolution and influencing factors in the mining of extra-thick coal seam beneath the protective layer through theoretical analysis, numerical simulation, and field observation. The results indicate that increasing the excavation height of the coal seam will lead to the upward development of the collapse zone in the overburden of the goaf, with the “masonry beam” structure formed at a higher position by key strata blocks. The overburden above the masonry beam will be supported by the coal rock masse on both sides of the structure, leading to increased stress on the coal seam near the goaf and eliminating the depressurisation effect of the protective layer. Numerical simulation shows that factors such as faults, protective layers, interlayer spacing, and the height of coal seam excavation significantly affect the stress distribution in the protected layer. With the increase in interlayer spacing and the thickness of coal seam extraction, the stress reduction phenomenon of the UPL gradually decreases, especially with an abnormal stress concentration of the gob-side coal seam. Observations of Surface subsidence and the distribution of mining-induced seismic events corroborate the conclusions of theoretical analysis and numerical simulations. The results offer valuable guidance for the mining of extra-thick coal seams and the selection of the UPL.

Abstract Biomanipulation has been widely used in the ecological restoration of eutrophic lakes for decades. However, biomanipulation is prone to failure if external nutrient loads are not reduced. In order to explore the importance of filter‐feeding fish and bivalves on algal control, an outdoor mesocosm experiment was conducted using different nutrient concentrations. Four treatments simulating daily loads of nutrients in Lake Taihu were studied: current, two times, and three times average daily loads of nutrients with both fish (Aristichthys nobilis) and Asian clam (Corbicula fluminea) and as a control current daily loads without fish or bivalves. Results showed that stocking of filter‐feeding fish and bivalves (80 g m−3 bighead carp; 200 g cm−2 clams) at two times daily nutrient loads could effectively control water column Chl a concentrations and phytoplankton biomass. At higher nutrient concentrations (TN ≥ 260 μg L−1 d−1; TP ≥ 10 μg L−1 d−1), top‐down control of filter‐feeding fish and bivalves was less effective and bottom‐up effects resulted in significant increases of Chl a concentration. Thus, as phytoplankton biomass in freshwater ecosystems is determined by both the top‐down effects of predators and the bottom‐up effects of nutrients, external loadings should be controlled when filter‐feeding fish and bivalves are used for algal control to ensure the efficacy of biomanipulation.

Abstract Dissolved organic matter (DOM) composition in lakes is controlled by multiple environmental drivers, but the relative importance of various drivers remains poorly understood at the continental scale. Here, we established a model resolving possible influencing pathways of climate, land cover, societal development, and water retention time of lakes on the quantity and quality of chromophoric DOM (CDOM) from 182 lakes spanning across strong climatic and economic gradients in China. Our results indicate that land cover and societal development both exhibit positive direct effects on lake CDOM quantity, highlighting the significant role of well‐vegetated soils and anthropogenic activities as sources of lake DOM on a continental scale. Climate has two strong but opposite effects—a warming and wet climate facilitates soil OM production and export, while it also enhances CDOM in‐lake transformation. Three proxies are proposed as indicators of the magnitude of biogeochemical drivers influencing lake DOM across different ecoclimatic zones, including fluorescent DOM/DOC indicating economic activity, percentages of a degraded fluorescent DOM component indicating solar irradiation, and percent tyrosine‐like DOM reflecting DOM processing time within the watershed and lake. Collectively, our findings indicate that the effects of climate change and rapid societal development will result in increased loadings of terrestrial and anthropogenic DOM into lakes and drive higher rates of within‐lake processing of DOM. Consequently, lakes will play a more important role as an “active pipe” in mediating the flux and transformation of organic carbon, intensifying the coupling between terrestrial and aquatic carbon cycles on a continental scale.

Experimental fracture mechanics at the microscale became an indispensable tool for understanding and analyzing the solder joint degradation in microelectronics packaging, which is facing severe temperature swings and is prone to failure due to the delamination induced by the microcracks. In this work, we studied the fracture behavior of the widely used Sn-based solder on microscale with the notched microcantilevers fabricated using the focused ion beam (FIB) milling. The microcantilever bending tests were performed to demonstrate the fracture process by the nanoindentation system. Besides, the continuous stiffness measurement (CSM) for the dynamic stiffness was applied to assess the crack behavior. Crack resistance was obtained from the J-Δa curves and the fracture toughness was calculated from the bending tests based on the elastic-plastic fracture mechanics. The results indicated that the fracture toughness decreased after the thermal cycling test. Compared to the specimen without aging, the resistance to rupture decreases rapidly and tends to a low variation against the increased aging cycles. Moreover, the grain orientations and dislocation densities were analyzed using electron back-scatter diffraction (EBSD). It was found that the dislocation density and misorientations of the aged specimens correlated closely to fracture toughness. Furthermore, the stress distribution of the crack tip and the deformation in the plastic zone were analyzed by the finite element simulations. This work provided new insight into the degradation of fracture and deformation behavior of solder material on microscale and revealed the relationship of crack resistance and thermal cycling aging.

BACKGROUND The food security problem caused by heavy metal pollution in farmland soil has attracted widespread attention. Objective pollution investigation and evaluation work is of great significance for the later pollution prevention and safe utilization of soil. OBJECTIVES To fully understand the heavy metal contamination condition, ecological risk and human health risk of soil and rice in the farmland around the copper-lead-zinc tailing pond in Western Hubei Province. METHODS 50 sites of topsoil and rice were investigated systematically. ICP-MS, ICP-OES and AFS were used to determine the contents of eight heavy metals (As, Cd, Cu, Pb, Zn, Hg, Ni, Cr), as well as the pH value of the soil. The potential ecological risk index method and human health risk assessment model were used to evaluate the potential ecological risk and health risk of soil and rice. RESULTS The results indicate that: (1) The contents of As, Cd, Cu, Pb and Zn in the soil exceed the standard, with the maximum exceedance rate of Cd being 20%. Only Cd in rice exceeds the standard with the exceedance rate of 14%. (2) Correlation analysis shows that soil heavy metals have the same pollution source, and leachate leakage is a possible source of pollution. There is a positive correlation between the heavy metals in rice and the surface soil, with the strongest correlation for Cd, which may be related to the strong absorption capacity of rice for soil Cd. (3) The evaluation results of potential ecological risk index show that Cd, Pb, Zn and Cu are significantly enriched in the soil, with the Cd enrichment coefficient of 4.41. The overall ecological risk is moderate, with 6% of the sites having very strong potential ecological risk. (4) The results of the health risk assessment indicate that the total and non-total carcinogenic risks are greater than the acceptable level at almost all sites. There is an overall risk of heavy metal carcinogenicity in the soil, with As and Cd being the major contributors. The total non-carcinogenic risk for rice at almost all sites in the study area is greater than the acceptable level, with Cd being the largest contributor. The total non-carcinogenic risk for rice at all sites is within the acceptable level. CONCLUSIONS The soil and rice in the vicinity of the tailings pond have been contaminated by heavy metals, posing a certain ecological risk, and the risks to the health of the local population should be taken into account.

Directional hydraulic fracturing (DHF) is more and more widely used in coal mines in China for hard roof and coal burst control. The key to this technology is to determine the crack initiation pressure that affected by the shape of the artificial notch and the stress state around the fracturing hole. Reasonable and simple formula for fracturing pressure calculation is essential since the fracturing pump used in coal mines is usually limited by the harsh conditions and hardly replaced once selected. Based on the superposition principle, the simplified 2D model of DHF was established as the elliptical hole with the internal pressure and solved by using the complex functions method. The analytical solution of tangential stress on the inner surface was obtained meanwhile the corresponding criterion of fracturing pressure can be set up. Considering the characteristics of DHF in coal mines, we further got a simplified formula that controlled by the ratio of major to minor axis of the ellipse-like notch, the ratio of the minimum to the maximum principal stress, as well as the tensile strength of the rock. The formula also gave a guide to the design of the notch that major diameter should be at least twice the minor diameter, and the optimal solution for the ratio is to 2～4 and recommended 4, which can resist the initiation pressure to a large extent affected by the in-situ stress. Once the pressure of the fracturing fluid is high enough to satisfy the equation cracks would arise at the tips of the notch along the major axis which belongs to mode Ⅰ crack and would grow unsteadily and rapidly. A PFC simulation model was used to verify the analysis, the results of which are very consistent with the theoretical solutions.

Micropillar array electrodes represent a promising avenue for enhancing detection sensitivity and response current. However, existing methods for depositing electrode materials on micropillar arrays often result in uneven distribution, with the thin sidewall layer being less conductive and prone to corrosion. In addressing this issue, this study introduces electroplating to enhance the copper layer on the sidewall of micropillar array electrodes. These electrodes, fabricated through standard microelectronics processes and electroplating, are proposed for non-enzymatic glucose detection, with the copper layer deposited via electroplating significantly enhancing sensitivity. Initially, the impact of cetyltrimethylammonium bromide (CTAB) concentration as an inhibitor on the surface morphology and sensitivity of the plated layer was investigated. It was discovered that CTAB could decrease surface roughness, hinder the development of large and coarse grains, generate small particles, and boost sensitivity. Compared to the uncoated electrode and plating without CTAB, sensitivity was elevated by a factor of 1.66 and 1.62, respectively. Subsequently, the alterations in plating morphology and detection performance within a range of 0.3 ASD to 3 ASD were examined. Sensitivity demonstrated a tendency to increase initially and then decrease. The electrode plated at 0.75 ASD achieved a maximum sensitivity of 3314 μA·mM−1·cm−2 and a detection limit of 15.9 μM. Furthermore, a potential mechanism explaining the impact of different morphology on detection performance due to CTAB and current density was discussed. It was believed that the presented effective strategy to enhance the sensitivity of micropillar array electrodes for glucose detection would promote the related biomedical detection applications.

The damage evolution rules for coal under true triaxial combined static–dynamic loads are important to understand and reveal the mechanism of rockburst in coal mines. The numerical simulation was carried out using FLAC3D to explore the coupling effect of static and dynamic stress, especially the influence of dynamic load parameters. The results show that the increase in dynamic load amplitude not only makes the plastic zone grow exponentially and shortens the damage development time, but also decreases the residual strength of the coal sample, which leads to a much more violent dynamic failure. The stress wave propagation can be more stable in the coal sample with the increase in dynamic load frequency and the development time of the plastic zone also shows synchronous fluctuating features, and when the frequency is like the intrinsic frequency of the coal sample, the dynamic load has a significant stimulation effect. The static and dynamic loads have different damage effects on the coal sample under the true triaxial stress path, the weight decreases in descending order, namely the minimum principal stress, the maximum principal, the amplitude of the dynamic load and, lastly, the dynamic stress frequency, according to the entropy weight method analysis.

The development of nanohybrid with high electrocatalytic activity is of great significance for electrochemical sensing applications. In this work, we develop a novel and facile method to prepare a high-performance flexible nanohybrid paper electrode, based on nitrogen-doped carbon (NC) wrapped Bi nanoparticles (Bi-NPs) assembly derived from Bi-MOF, which are decorated on a flexible and freestanding graphene paper (GP) electrode. The as-obtained Bi-NPs encapsulated by an NC layer are uniform, and the active sites are increased by introducing a nitrogen source while preparing Bi-MOF. Owing to the synergistic effect between the high conductivity of GP electrode and the highly efficient electrocatalytic activity of Bi-NPs, the NC wrapped Bi-NPs (Bi-NPs@NC) modified GP (Bi-NPs@NC/GP) electrode possesses high electrochemically active area, rapid electron-transfer capability, and good electrochemical stability. To demonstrate its outstanding functionality, the Bi-NPs@NC/GP electrode has been integrated into a handheld electrochemical sensor for detecting heavy metal ions. The result shows that Zn2+, Cd2+, and Pb2+ can be detected with extremely low detection limits, wide linear range, high sensitivity, as well as good selectivity. Furthermore, it demonstrates outstanding electrochemical sensing performance in the simultaneous detection of Zn2+, Cd2+, and Pb2+. Finally, the proposed electrochemical sensor has achieved excellent repeatability, reproducibility, stability, and reliability in measuring real water samples, which will have great potential in advanced applications in environmental systems.

Practice and theory research proved the “square effect” during longwall mining with hard–thick strata lying on the coal seam, which could cause severe underground pressure and even dynamic disasters, such as coal burst; therefore, it became a key area and stage that need special attention. The combined active–passive seismic computed tomography (CT) was introduced to detect the abutment stress concentration in the coal seam. The results of active–passive CT inversion show that the “square effect” appears as early as the workface ahead of the theoretical position of 50 m with a 100 m significant influencing zone, which provides a strong guarantee for accurate risk evaluation of coal burst. Precursor information before the “square effect” can be identified based on the everyday total energy of mining tremors, which had period peaks in this case. The everyday average energy of mining tremors indicates that the seismic type during the “square effect” stage belonged to a foreshock–mainshock pattern. The combination of the seismic events and CT can improve the accuracy of coal burst danger distinguishing notably. The research can provide worthwhile guidance for the monitoring and prevention of coal burst hazards in similar conditions.

Intraguild predation (IGP) can have a significant impact on phytoplankton biomass, but its effects on their diversity and assemblage composition are not well understood. In this study, we constructed an IGP model based on the common three-trophic food chain of “fish (or shrimp)–large branchiopods (Daphnia)–phytoplankton”, and investigated the effects of IGP on phytoplankton assemblage composition and diversity in outdoor mesocosms using environmental DNA high-throughput sequencing. Our results indicated that the alpha diversities (number of amplicon sequence variants and Faith’s phylogenetic diversity) of phytoplankton and the relative abundance of Chlorophyceae increased with the addition of Pelteobagrus fulvidraco, while similar trends were found in alpha diversities but with a decrease in the relative abundance of Chlorophyceae in the Exopalaemon modestus treatment. When both predators were added to the community, the strength of collective cascading effects on phytoplankton alpha diversities and assemblage composition were weaker than the sum of the individual predator effects. Network analysis further showed that this IGP effect also decreased the strength of collective cascading effects in reducing the complexity and stability of the phytoplankton assemblages. These findings contribute to a better understanding of the mechanisms underlying the impacts of IGP on lake biodiversity, and provide further knowledge relevant to lake management and conservation.

Rockburst is one of the main dynamic disasters in coal mines; it is of great significance to accurately evaluate the risk zoning of rockburst for mine safety construction and pressure relief design. Taking the Gaojiapu coal mine in the Bingchang mining area of Shaanxi Province as the study area, this paper quantifies the complex geological structure based on fractal theory and establishes the zoning evaluation model of rockburst risk index in the mining area by LS-FAHP-CRITIC method in combination with the distribution characteristics of field stress field, the distribution of geological structure, and the sedimentary environment of coal seam overburden. A new evaluation method of rockburst risk zoning in the coal mine is proposed, and the rockburst risk in the study area was evaluated. The results show that the dangerous areas in the study area are widely distributed, mainly in the area near the structure with high maximum horizontal principal stress. On the basis of the actual rockburst of the Gaojiapu coal mine, the areas where rockburst occurs are all located in dangerous area and high dangerous area, which verifies the accuracy and rationality of the zoning evaluation results of the new method. This method can be used to guide the safety production of similar mines or adjacent coalfaces.

Fatty acids (FAs) are critical nutrients that regulate an organism’s health and development in mammal. Long-chain fatty acids (LCFAs) can be divided into saturated and unsaturated fatty acids, depending on whether the carbon chain contains at least 1 double bond. The fatty acids that are required for humans and animals are obtained primarily from dietary sources, and LCFAs are absorbed from outside of cells in mammals. LCFAs enter cells through several mechanisms, including passive diffusion and protein-mediated translocation across the plasma membrane, the latter in which FA translocase (FAT/CD36), plasma membrane FA-binding protein (FABPpm), FA transport protein (FATP), and caveolin-1 are believed to have important functions. The LCFAs that are taken up by cells bind to FA-binding proteins (FABPs) and are transported to the specific organelles, where they are activated into acyl-CoA to target specific metabolic pathways. LCFA-CoAs can be esterified to phospholipids, triacylglycerol, cholesteryl ester, and other specialized lipids. Non-esterified free fatty acids are preferentially stored as triacylglycerol molecules. The main pathway by which fatty acids are catabolized is β-oxidation, which occurs in mitochondria and peroxisomes. stearoyl-CoA desaturase (SCD)-dependent and Fatty acid desaturases (FADS)-dependent fatty acid desaturation pathways coexist in cells and provide metabolic plasticity. The process of fatty acid elongation occurs by cycling through condensation, reduction, dehydration, and reduction. Extracellular LCFA can be mediated by membrane protein G protein-coupled receptor 40 (GPR40) or G protein-coupled receptor 120 (GPR120) to activate mammalian target of rapamycin complex 1 (mTORC1) signaling, and intracellular LCFA’s sensor remains to be determined. The crystal structures of a phosphatidic acid phosphatase and a membrane-bound fatty acid elongase-condensing enzyme and other LCFA-related proteins provide important insights into the mechanism of utilization, increasing our understanding of the cellular uptake, metabolism and sensing of LCFAs.

The effectiveness of controlling nitrogen (N) to manage eutrophication of aquatic ecosystems remains debated. To understand the mechanisms behind phytoplankton growth in shallow lakes (resource and grazing effects) under contrasting N loading scenarios, we conducted a 70-days mesocosm experiment in summer. The mesocosms contain natural plankton communities deriving from a 10-cm layer of lake sediment and 450 L of lake water. We also added two juvenile crucian carp (Carassius carassius) in each mesocosm to simulate presence of the prevailing omni-benthivorous fish in subtropical lakes. Our results showed that N addition increased not only water N levels but also total phosphorus (TP) concentrations, which together elevated the phytoplankton biomass and caused strong dominance of cyanobacteria. Addition of N significantly lowered the herbivorous zooplankton to phytoplankton biomass ratio and promoted the phytoplankton yield per nutrient (Chl-a: TP or Chl-a: TN ratio), indicating that summer N addition likely also favored phytoplankton growth through reduced grazing by zooplankton. Accordingly, our study indicates that summer N loading may boost eutrophication via both changes in resource and grazing control in shallow lakes. Thus, alleviation of eutrophication in shallow eutrophic lakes requires a strategic approach to control both nutrients (N and P) appropriately.

One of the key factors to improve electrochemical properties is to find exceptional electrode materials. In this work, the nickel-cobalt layered double hydroxide (CNT@CoS/NiCo-LDH) with the structure of a hollow nanocage was prepared by etching CNT@CoS with zeolitic imidazolate framework-67 (ZIF-67) as a template. The results show that the addition of nickel has a great influence on the structure, morphology and chemical properties of materials. The prepared material CNT@CoS/NiCo-LDH-100 (C@CS/NCL-100) inherited the rhombic dodecahedral shape of ZIF-67 well and the CNTs were evenly interspersed among the rhombic dodecahedrons. The presence of CNTs improved the conductivity and surface area of the samples. The C@CS/NCL-100 demonstrates a high specific capacitance of 2794.6 F·g−1 at 1 A·g−1. Furthermore, as an assemble device, the device of C@CS/NCL-100 as a positive electrode exhibits a relatively high-energy density of 35.64 Wh·kg−1 at a power density of 750 W·kg−1 Further, even at the high-power density of 3750 W·kg−1, the energy density can still retain 26.38 Wh·kg−1. Hence, the superior performance of C@CS/NCL-100 can be ascribed to the synergy among CNTs, CoS and NiCo LDH, as well as the excellent three-dimensional structure obtained by used ZIF-67 as a template.

Marine aerosol is one of the most important natural aerosols. It has a significant impact on marine climate change, biochemical cycling and marine ecosystems. Previous studies on marine aerosols, especially in the South China Sea, were carried out by satellite and shipborne measurements. The above methods have drawbacks, such as low temporal–spatial resolution and signal interference. However, lidar has high accuracy and high temporal–spatial resolution, so it is suitable for high-precision long-term observations. In this work, we obtain marine aerosol data using Mie Lidar in Sansha, an island in the South Chain Sea. Firstly, by comparing boundary layer height (BLH) between Sansha and Hefei, we found that Sansha’s boundary layer height has significant differences with that of inland China. Secondly, we compare the aerosol extinction coefficients and their variation with height in Sansha and Hefei. Finally, we obtain hourly averaged aerosol optical depth at Sansha and explore its relation with weather. To analyze the AOD–weather relation, we select three meteorological factors (sea surface temperature, mean sea level pressure and 10 m u-component of wind) based on their feature importance, which is determined by random forest regression. We also analyze the relationship between AOD and the above meteorological factors in each season separately. The results show that there is a strong relation between the meteorological factors and AOD in spring and summer, while there is no clear correlation in fall and winter. These analyses can provide valid data for future researches on marine aerosols in the South China Sea.

To study fracture evolution and peak stress in burst risk coal samples (BRCSs) under true triaxial loading and unloading conditions, experimental and numerical research was applied to BRCSs under true triaxial stress paths entailing “x-direction displacement fixed, y-direction loading, z-direction unloading.” Both the experimental and the numerical results demonstrated that the peak stress borne by the BRCSs was not only affected by the initial stress but also had a negative exponential relationship with the ratio of the unloading rate and the loading rate (RURLR); therefore, peak stress equations of BRCSs under true triaxial loading and unloading conditions were established. The triaxial stress-time curves obtained by experiments and simulations exhibited an “elasticity-yield-destruction” phase, and the characteristics of the yield phase were determined by the RURLR. A typical BRCS was selected for velocity tomographic imaging to analyze the fracture evolution characteristics under true triaxial loading and unloading. The results showed that when the BRCS was subjected to a triaxial state of stress, the high- and low-velocity regions existed alternately due to the presence of the crack; during the elastic phase, the crack closed during loading in the previous phase was reopened upon unloading, so that the velocity of the sample decreased and a wide range of low-velocity regions could be formed; when entering the yield phase, the original crack continued to expand into a hole-through crack, leading to wider extreme values and ranges of these low- and high-velocity regions; at the breaking phase, multiple microcracks were generated around the hole-through cracks, decreasing the overall velocity, and showing point distributions characteristics of high- and low-velocity regions. Overall, many low-velocity regions with similar normal directions to the unloading direction were formed; these correlated well with macrofractures (postfailure).

In the process of waterflooding development, high waterflooding PVs will make the fluid percolation in the reservoir more complicated, resulting in lower efficiency of waterflooding. High waterflooding PVs will affect the relative permeability and change the seepage law of oil–water two-phase flow in a high water-cut period. In this study, we performed high waterflooding PVs relative permeability experiments using nine natural cores. The unsteady measurement method is used to test the relative permeability curve. The results show that: (1) the relative permeability is affected by the waterflooding PVs, the recovery efficiency of 2000 waterflooding PVs is 10.72% higher than that of 50 waterflooding PVs on the core scale; (2) it makes water mobility increase sharply, while oil phase flow capacity remains low and decreases at high water cut stage. A new relative permeability characterization method considering high waterflooding PVs is established, which is applied to the numerical simulator. It shows that the remaining oil saturation of the high-permeability belt is higher than the calculation results of the traditional numerical simulator. It means that the injected water does not diffuse much into the low-permeability zone of the formation. The modified simulator is validated with the actual China offshore oilfield model. The numerical saturation of the key section of the passing well is in good agreement with the actual logging interpretation results, and the water cut curve fits better in the whole area. The modified simulator could predict oil production accurately after high waterflooding PVs treatment.

Water level is one of the most important factors affecting the growth of submerged macrophytes in aquatic ecosystems. The rosette plant Vallisneria natans and the erect plant Hydrilla verticillata are two common submerged macrophytes in lakes of the middle and lower reaches of the Yangtze River, China. How water level fluctuations affect their growth and competition is still unknown. In this study, three water depths (50 cm, 150 cm, and 250 cm) were established to explore the responses in growth and competitive patterns of the two plant species to water depth under mixed planting conditions. The results show that, compared with shallow water conditions (50 cm), the growth of both submerged macrophytes was severely suppressed in deep water depth (250 cm), while only V. natans was inhibited under intermediate water depth (150 cm). Moreover, the ratio of biomass of V. natans to H. verticillata gradually increased with increasing water depth, indicating that deep water enhanced the competitive advantage of V. natans over H.verticillata. Morphological adaptation of the two submerged macrophytes to water depth was different. With increasing water depth, H. verticillata increased its height, at the cost of reduced plant numbers to adapt to poor light conditions. A similar strategy was also observed in V. natans, when water depth increased from 50 cm to 150 cm. However, both the plant height and number were reduced at deep water depth (250 cm). Our study suggests that water level reduction in lake restoration efforts could increase the total biomass of submerged macrophytes, but the domination of key plants, such as V. natans, may decrease.

High repetitions of a character induce a feeling of uncertainty of the character. This phenomenon is named as Verbal Satiation. However, the locus and nature of the verbal satiation remain controversial. To investigate whether verbal satiation occurs at the lexical representational locus, we used rarely used Chinese characters as stimuli to exclude confounding factor of meaning access. Participants were asked to judge whether or not a single Chinese character such as “” is a composition of a rarely used Chinese character such as “.” The experiment consists of 4 sets with 11 blocks in each set. Every 20 trials consist of a block, and the same rarely used characters were repeated in half of these trials. To observe the satiation effect that is offset by practice effect with more statistical power, we did ANOVA analysis for each set. The statistical results revealed that subjects responded differently at different time periods. In the first set, participants responded faster in later trials; After that, reversely, participants responded slower in later trials; Then they responded slower for the repeated characters in middle trials; Finally, participants responded slower for the repeated characters without regard to the trial position. These results show a competition process between satiation effect and practice effect and reveal that the verbal satiation can occur at a lexical representational locus.

Development of computer science has led to the blooming of artificial intelligence (AI), and neural networks are the core of AI research. Although mainstream neural networks have done well in the fields of image processing and speech recognition, they do not perform well in models aimed at understanding contextual information. In our opinion, the reason for this is that the essence of building a neural network through parameter training is to fit the data to the statistical law through parameter training. Since the neural network built using this approach does not possess memory ability, it cannot reflect the relationship between data with respect to the causality. Biological memory is fundamentally different from the current mainstream digital memory in terms of the storage method. The information stored in digital memory is converted to binary code and written in separate storage units. This physical isolation destroys the correlation of information. Therefore, the information stored in digital memory does not have the recall or association functions of biological memory which can present causality. In this paper, we present the results of our preliminary effort at constructing an associative memory system based on a spiking neural network. We broke the neural network building process into two phases: the Structure Formation Phase and the Parameter Training Phase. The Structure Formation Phase applies a learning method based on Hebb's rule to provoke neurons in the memory layer growing new synapses to connect to neighbor neurons as a response to the specific input spiking sequences fed to the neural network. The aim of this phase is to train the neural network to memorize the specific input spiking sequences. During the Parameter Training Phase, STDP and reinforcement learning are employed to optimize the weight of synapses and thus to find a way to let the neural network recall the memorized specific input spiking sequences. The results show that our memory neural network could memorize different targets and could recall the images it had memorized.

Flexible electronics such as flexible sensors play a significant role in the daily life. In this work, a simple sintering method was proposed to produce a flexible sensing component. In contrast with conventional Ag NPs based flexible conductive patterns, CNT enhanced flexible components were prepared, which can improve the sintering efficiency and mechanical durability against bending tests significantly. The effects of different CNT content in the composites on the electrical and mechanical performance were discussed. It was found the prepared samples with CNT wt% as 2% obtained improved mechanical durability and reliable electrical property against bending test for 20000 bending cycles in this work. Furthermore, the mechanism of CNT enhancement was discussed. Finally, a successful gesture detection application based on the prepared composites was demonstrated.

The present research contributes to the debate in cognitive sentence on the relationship between language and perception by comparing Mongolian and Chinese speakers’ color perception. In this study, featuring a free sorting task and a visual search task comparing Mongolian and Chinese performances, the results show that both universal and relativistic forces are at play. Chinese (Mandarin) and Mongolian color terms divide the blue spectrum differently but the green spectrum, similarly. In Mongolian, light blue (“qinker”) and dark blue (“huhe”) are strictly distinct, while both light green and dark green are described as one word, nogvgan. In Chinese, however, both light blue and dark blue are simply described by one word, lan, and both light green and dark green are described by a single word, lv. The current study used a free-sorting task and a visual search task to investigate whether this linguistic difference between Chinese and Mongolian speakers leads to a difference in color discrimination. In the free-sorting task, compared with Chinese speakers, Mongolian speakers exhibited different sorting in the blue region (by distinguishing light and dark blue) and the same sorting in the green region. Further results showed that Mongolian speakers discriminated visual search displays that fall into different linguistic categories in Mongolian (e.g., qinker or huhe) more quickly than visual search displays that belong to the same linguistic category (e.g., both qinker) in a visual search task. Moreover, this effect was disrupted in Mongolian participants who performed a secondary task engaging involving verbal working memory (but not a task engaging involving spatial working memory), suggested linguistic interference. Chinese (Mandarin) speakers performing the visual search task did not show such a category advantage under any of the conditions. The finding provides support for the Whorf hypothesis with evidence from an Altay language. Meanwhile, both Chinese and Mongolian speakers reacted faster to the green color than the blue color in the visual search task, suggesting that the variation in human color perception is constrained by certain universal forces. The difference in categorical effects between Chinese and Mongolian speakers in the blue region suggests a relativistic aspect of language and color perception, while the speed of visual search in blue and green suggests a universalistic aspect of language and color perception. Thus, our findings suggest that our perception is shaped by both relativistic and universal forces.

It is evident through biology research that, biological neural network could be implemented through two means: by congenital heredity, or by posteriority learning. However, traditionally, artificial neural network, especially the Deep learning Neural Networks (DNNs) are implemented only through exhaustive training and learning. Fixed structure is built, and then parameters are trained through huge amount of data. In this way, there are a lot of redundancies in the implemented artificial neural network. This redundancy not only requires more effort to train the network, but also costs more computing resources when used. In this paper, we proposed a bionic way to implement artificial neural network through construction rather than training and learning. The hierarchy of the neural network is designed according to analysis of the required functionality, and then module design is carried out to form each hierarchy. We choose the Drosophila's visual neural network as a test case to verify our method's validation. The results show that the bionic artificial neural network built through our method could work as a bionic compound eye, which can achieve the detection of the object and their movement, and the results are better on some properties, compared with the Drosophila's biological compound eyes.

A true triaxial loading and unloading experiment entailing “y-direction stress loading, z-direction stress unloading, and x-direction displacement fixing” of coal samples was conducted. Through analysis of the stress characteristics, fracture characteristics, and energy evolution in coal samples, the mechanical and coal burst breeding mechanisms of coal samples under true triaxial loading and unloading were revealed. The experiment found that the yield stress and peak stress of coal samples were not only affected by the initial loading and unloading of lateral stress but also had a negative exponential relationship with the ratio of the unloading rate and the loading rate (RURLR), thereby establishing the stress equation of coal samples under a true triaxial loading and unloading. There was a yield turning point in the stress-time curve of coal samples, and the difference in triaxial stress and acoustic emission before, and after, yield was significant. It was found that a high unloading rate and high initial stress are precursors to coal sample bursting. During loading and unloading, the high-energy area expanded, but its location was always fixed to within a certain area. The energy in this area was rapidly released to form a burst source when the sample was subjected to high-speed unloading. The nonbursting coal samples and the burst coal samples showed characteristic slabbing and bursting behaviours, respectively: the former corresponding to the acoustic emission energy value being two orders of magnitude lower than the latter. The research results can provide a reference for the study of mechanical behaviours and coal burst criteria in the rock surrounding a coal roadway excavation.

How fish communities change with eutrophication in temperate lakes is well documented, while only a few studies are available from subtropical lakes. We investigate the fish community structure in 36 lakes located in the Yangtze River basin, covering a wide nutrient gradient. We found that fish species richness and total fish catch per unit effort (CPUE) increased significantly with chlorophyll a (Chla). Among the different feeding types, the proportion of zooplanktivores increased significantly with Chla, while the percentage of omnibenthivores showed no obvious changes; the CPUE of piscivorous Culter spp. increased with Chla, while their proportion of total catch decreased pronouncedly. Based on the index of relative importance (IRI), the most important and dominant fish species was the zooplanktivorous Sijiao (Toxabramis swinhonis), followed by the omniplanktivorous sharpbelly (Hemiculter leucisculus) and the omnibenthivorous crucian carp (Carassius carassius), a small-sized species belonging to the Cyprinidae family. The CPUE of these three species increased significantly with Chla. The focus has, so far, been directed at large fish, but as emphasized by our results, the abundant small fish species were dominant in our subtropical study lakes even in terms of biomass, and, accordingly, we recommend that more attention be paid to the population dynamics of these species in the future.

Increased recruitment of small-sized fish following biomanipulation by reducing the biomass of plankti-benthivorous fish, not least in (sub)tropical lakes, may deteriorate water quality and thereby potentially hamper the recovery of submerged macrophytes. Filter-feeding bivalves remove suspended particles from the water and may, thereby, somewhat or fully counteract this negative effect of the increasing abundance of small-sized fish. So far, only few studies have investigated the interactive effects of fish and bivalves on water clarity and macrophyte growth. We conducted a 2 × 2 factorial designed outdoor mesocosm experiment with two densities of small crucian carp Carassius carassius (low 10 g m−2 and high 40 g m−2) and two densities of bivalves Corbicula fluminea (low 204 g m−2 and high 816 g m−2). We found significant interactive effect of fish and bivalves on the growth of the macrophyte Vallisneria natans. In the low density bivalve regime, the relative growth rates, root mass, root:shoot ratio and number of tubers were 30.3%, 30.8%, 21.6% and 27.8% lower in the high than in the low density fish treatments, while the decrease was less pronounced in the high density bivalve regime: 1.2%, 8.7%, 2.1% and 13.3%, respectively. Thus, bivalves reduced the negative effects of fish, not least when bivalve density was high. The weaker effects of small fish on plants in the high- than in the low-density C. fluminea regime can be attributed to lower total suspended solids (TSS) and Chl a in the first week of the experiment. Better light conditions further stimulated the growth of benthic algae, potentially increasing the removal of nutrients from the water and reducing fish-driven resuspension of the sediment. In addition, high densities of C. fluminea also enriched the sediment total nitrogen (TN) and total phosphorus (TP) content, favouring plant growth as indicated by an increase in leaf tissue TN and TP contents. Our results demonstrate that filter-feeding bivalves can alleviate harmful effects of small fish by prolonging a clear-water state that facilitates submerged macrophyte growth. Addition of the bivalve C. fluminea can be a promising tool for the restoration of submerged macrophytes in shallow eutrophic lakes, in particular lakes containing small, rapidly reproducing fish that due to their small sizes are not capable of controlling the bivalves.

A simplified method is presented to investigate the dynamic response of rock-socketed piles embedded in a layered foundation. The finite element method is utilized to derive the dynamic stiffness matrix equations of the pile modelled as a 1D bar, and the exact stiffness matrix method is employed to establish the flexibility matrix equations of the foundation modelled as a 3D body. According to the pilesoil interaction condition, these matrices are incorporated together to obtain the solution for the dynamic response of rock-socketed piles. Finally, some numerical results are given to illustrate the influence of rocksocketed depth on the pile vertical impedance.

The sintering of metal nanoparticles (NPs) has been widely studied in the field of nanotechnology, and low-temperature sintering has become the industry standard. In this study, a molecular dynamics (MD) model was established to study the sintering behaviour of silver NPs during low-temperature thermo-compression. Primarily, we studied the sintering process, in which the ratio of neck radius to particle radius (x/r) changes. Under a uniaxial pressure, the maximum ratio in the temperature range 420–425 K was 1. According to the change of x/r, the process can be broken down into three stages: the neck-formation stage, neck-growth stage, and neck-stability stage. In addition, the relationship between potential energy, internal stress, and dislocation density during sintering is discussed. The results showed that cycling internal stress played an important role in sintering. Under the uniaxial pressure, the stress-dislocation interaction was found to be the major mechanism for thermo-compression sintering because the plastic deformation product dislocation intensified the diffusion of atoms. Also, the displacement vector, the mean square displacement, and the changing crystal structure during sintering were studied.

In this work, the thermal properties of nanoscale SiO2 thin films have been systematically investigated with respect to the thickness, crystal orientations and the void defects using non-equilibrium molecular-dynamics (NEMD) simulation. Size effect for the lattice thermal conductivity of nanoscale SiO2 thin films was observed. Additionally, SiO2 thin films with [001] oriented exhibited greater thermal conductivity compared with other crystal orientations which was discussed in terms of phonon density of states (PDOS). Furthermore, the porosity of void defects was introduced to quantify the influence of defects for thermal conductivity. Results exhibited that the thermal conductivity degraded with the increase of porosity. Two thermal conductivity suppression mechanisms, namely, void defects induced material loss interdicting heat conduction and phonon scattering enhanced by the boundary of defects, were proposed. Then, a further simulation was deployed to find that the effect of boundary scattering of defects was dominant in thermal conductivity degradation compared with material loss mechanism. The conclusion suggests that the thermal conductivity could be configured via regulating the distribution of PDOS directly associated with void defects.

This study presents a segmentation pipeline that fuses colour and depth information to automatically separate objects of interest in video sequences captured from a quadcopter. Many approaches assume that cameras are static with known position, a condition which cannot be preserved in most outdoor robotic applications. In this study, the authors compute depth information and camera positions from a monocular video sequence using structure from motion and use this information as an additional cue to colour for accurate segmentation. The authors model the problem similarly to standard segmentation routines as a Markov random field and perform the segmentation using graph cuts optimisation. Manual intervention is minimised and is only required to determine pixel seeds in the first frame which are then automatically reprojected into the remaining frames of the sequence. The authors also describe an automated method to adjust the relative weights for colour and depth according to their discriminative properties in each frame. Experimental results are presented for two video sequences captured using a quadcopter. The quality of the segmentation is compared to a ground truth and other state‐of‐the‐art methods with consistently accurate results.

Eutrophication of lakes often results in dominance of cyanobacteria, which may potentially lead to serious blooms and toxic water. However, cyanobacterial detritus may act as an important carbon source for aquatic organisms. Using stable isotope carbon (13C) as a tracer, we assessed the carbon transfer from cyanobacteria to pelagic and benthic consumers in a 28-day outdoor mesocosm (~130 L) labelling experiment established in Lake Taihu, China, during a Microcystis aeruginosa bloom. The different organisms were labelled differently after addition of the labelled Microcystis detritus to the water. δ13C of particulate organic matter and of cladoceran zooplankton peaked earlier than for larger invertebrate consumers. Among the pelagic species, Daphnia similis had the highest Δδ13C, while the two snail species Radix swinhoei and Bellamya aeruginosa had lower but similar Δδ13C. The bivalves showed relatively modest changes in δ13C. The δ13C of Anodonta woodiana and Unio douglasiae showed a marginal though not significant increase, while a marked increase occurred for Arconaia lanceolate peaking on day 20, and Corbicula fluminea a slight increase peaking on day 9. Our results suggest that carbon from cyanobacteria can be incorporated by pelagic and some benthic consumers and eventually be transferred to higher trophic levels. Cyanobacterial carbon may, therefore, be considered an important carbon source supporting the entire food web during blooms, even if the cyanobacteria are not consumed directly.