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Abstract Explicit identification of hydrochemical processes and their controlling factors within groundwater systems is critical for the sustainable utilization of water resources in coastal urban areas. This study was undertaken in the North Coastal Region of Jiaozhou Bay (NCRJB), located in the eastern part of Shandong Province, China, an area grappling with significant issues of groundwater quality degradation and water scarcity. A total of 105 groundwater samples and 34 surface water samples, collected from 2020 to 2024, were analyzed and studied using various hydrogeological tools, multivariate statistical analyses, and water quality assessment methods. These include the Piper diagram, hydrochemical facies evolution diagram (HFE-D), Principal Components Analysis (PCA), correlation analysis, stable isotope analysis, Water Quality Index (WQI), and USSL diagrams. The results indicated that all surface water and pore groundwater samples were categorized as Na-Cl type, exhibiting high Total Dissolved Solids (TDS) and Electrical Conductivity (EC) values, characteristics that render them poor to unsuitable for drinking and irrigation purposes. The fracture groundwater is predominantly of the Ca-Na-Cl mixed type, with average suitability for irrigation and a limited proportion (22.5%) deemed suitable for drinking. Seawater intrusion, primarily through the surface water system, and the impact of human activities were identified as the predominant controlling factors con-tributing to the degradation of the local groundwater environment. Field empirical investigations further validated the results derived from hydrogeological assessments, multivariate statistical analyses, and isotopic approaches. The long-term shifts in hydrochemical properties, along with the latent threat of seawater intrusion, exhibit an upward trend during the dry season and show a certain degree of mitigation during the wet season. This study highlights that field investigations, in conjunction with hydrochemical tools, multivariate statistical analyses, and stable isotope analysis, can successfully furnish reliable insights into the predominant mechanisms governing regional groundwater evolution within the context of long-term and intricate envi-ronmental settings.

Abstract Geothermal energy has gained wide attention as a renewable alternative for mitigating greenhouse gas emissions. The advancements in enhanced geothermal system technology have enabled the exploitation of previously inaccessible geothermal resources. However, the extraction of geothermal energy from deep reservoirs poses many challenges due to high‐temperature and high‐geostress conditions. These factors can significantly impact the surrounding rock and its fracture formation. A comprehensive understanding of the thermal–hydraulic–mechanical (THM) coupling effect is crucial to the safe and efficient exploitation of geothermal resources. This study presented a THM coupling numerical model for the geothermal reservoir of the Yangbajing geothermal system. This proposed model investigated the geothermal exploitation performance and the stress distribution within the reservoir under various combinations of geothermal wells and mass flow rates. The geothermal system performance was evaluated by the criteria of outlet temperature and geothermal productivity. The results indicate that the longer distance between wells can increase the outlet temperature of production wells and improve extraction efficiency in the short term. In contrast, the shorter distance between wells can reduce the heat exchange area and thus mitigate the impact on the reservoir stress. A larger mass flow rate is conducive to the production capacity enhancement of the geothermal system and, in turn causes a wider range of stress disturbance. These findings provide valuable insights into the optimization of geothermal energy extraction while considering reservoir safety and long‐term sustainability. This study deepens the understanding of the THM coupling effects in geothermal systems and provides an efficient and environmentally friendly strategy for a geothermal energy system.

Abstract Temperature significantly influences the physical parameters of granite, resulting in variations in the rock's thermal conductivity. In order to examine the impact of changes in multiple physical parameters of granite at different temperatures on the thermal conductivity of rocks, Principal Component Analysis (PCA) was employed to determine the correlation between granite at different temperatures and various physical parameters, including density (ρ), P-wave velocity (P), thermal conductivity (K T ), and thermal diffusion coefficient (K D ). Utilizing the linear contribution rate, a single indicator 'y' was derived to comprehensively represent the thermal conductivity of rocks. Research findings indicate that within the temperature range of 150–450 °C, the 'y'-value is relatively high, signifying favorable thermal conductivity of the rock. Notably, longitudinal wave velocity demonstrates higher sensitivity to temperature changes compared to other physical parameters.

This paper focuses on detecting and tracking maneuvering weak targets in the range–Doppler (RD) plane with the track-before-detect (TBD) algorithm based on dynamic programming (DP). Traditional DP-TBD algorithms integrate target detection and tracking in their framework while searching the paths provided by a predefined model of the kinematic properties within the constraints allowed. However, both the approximate motion model used in the RD plane and the model mismatch caused when the target undergoes a maneuver can degrade the TBD performance sharply. To address these issues, this paper accurately describes the evolution of the RD equation based on Constant Acceleration (CA) and Coordinated Turn (CT) motion models with the process noise in the Cartesian coordinate system, and it also employs a recursive method to estimate the parameters in the equations for efficient energy accumulation and path searches. Facing the situation that targets energy accumulation during the DP iteration process will lead to an expansion of the target energy accumulation process. This paper designs a more efficient Optimization Function (OF) to inhibit the expansion effect, improve the resolution of the nearby targets, and increase the detection probability of the weak targets simultaneously. In addition, to search the trajectory more efficiently and accurately, we improved the process of DP multi-frame accumulation, thus reducing the computation amount of large-scale searches. Finally, the effectiveness of the proposed method for CA and CT motion target detection and tracking is verified by many of the simulation experiments that were conducted in this paper.

Abstract The Z-scan technique uses a single beam that can be used for observing the nonlinear or optical limiting properties of materials. For the first time, the Z-scan properties dependent on the polarization of 2D carbon nanomaterial suspension were experimentally investigated using optical Z-scan technology. The Z-scan curves of graphene and graphene oxide (GO) in N-methyl-2-pyrrolidinone suspensions exhibited strong polarization-dependent characteristics. In paper, a reverse saturated absorption (RSA) dip surrounded the lens focus when the horizontal polarized beam was focused in the suspension, and two saturated absorption (SA) peaks appeared adjacent to the dip. However, for the vertical polarized beam, only one RSA dip surrounded the lens focus, and the threshold was higher than the SA for a horizontally polarized beam. The transmission of RSA for the GO suspension was evidently lower than that of the graphene suspension. The polarization-dependent characteristic can be ascribed to the laser-induced alignment in case the suspension is moved in or out of the beam focal point. Furthermore, the polarization-dependent 2D carbon nanomaterial suspension can be applied in several practical purposes such as 2D material-based optical and opto-fludic devices.

In order to analyze the change rule of the pore structure of different thermal treated granites and quantitatively characterize the distribution characteristics of effective pores, the pore structure characteristics of high-temperature granites under different cooling modes are tested based on nuclear magnetic resonance (NMR) technology. It is found that when the temperature is 150 °C, water-cooling will reduce the number of rock pores, and the phenomenon of “thermal hardening” is obvious. When the temperature is 300 °C, the micropore diameter increases and part of it changes into mesopore pores. When the temperature is 450 °C, the mesopore pores occupy the dominant position, and the pore types are relatively concentrated. When the temperature is 600 °C, exceeding the quartz phase change temperature (573 °C), the number and pore diameter of rock pores increase dramatically, and even macropores appear. The pore size of rocks under different heat treatments has fractal characteristics, and fractal dimension models related to pore size can be established. Based on the fractal dimension model, the thermal storage properties of different thermal treated granites are discussed, and the optimal temperature conditions (450 °C and 600 °C) for the thermal storage properties of macroporous and mesoporous pores are found.

H7N9 avian influenza viruses have caused severe harm to the global aquaculture industry and human health. For further understanding of the characteristics of prevalence and hemagglutinin evolution of H7N9 avian influenza viruses, we generated the global epidemic map of H7N9 viruses from 2013 to 2022, constructed a phylogenetic tree, predicted the glycosylation sites and compared the selection pressure of the hemagglutinin. The results showed that although H7N9 avian influenza appeared sporadically in other regions worldwide, China had concentrated outbreaks from 2013 to 2017. The hemagglutinin genes were classified into six distinct lineages: A, B, C, D, E and F. After 2019, H7N9 viruses from the lineages B, E and F persisted, with the lineage B being the dominant. The hemagglutinin of highly pathogenic viruses in the B lineage has an additional predicted glycosylation site, which may account for their persistent pandemic, and is under more positive selection pressure. The most recent ancestor of the H7N9 avian influenza viruses originated in September 1991. The continuous evolution of hemagglutinin has led to an increase in virus pathogenicity in both poultry and humans, and sustained human-to-human transmission. This study provides a theoretical basis for better prediction and control of H7N9 avian influenza.

Aggregation-induced emission (AIE) fluorescence probes are indispensable for biomedical imaging, however, interference with tissue autofluorescence results in low signal-to-noise ratio limiting the development of bioimaging with AIE materials. Here the authors develop AIEgen room-temperature phosphors with long emission lifetimes efficiently eliminating intereference with the background signal in imaging.

Background Thrombocytopenia, an early common complication in heatstroke (HS), has been widely considered as a mortality predictor of HS. The mechanism underlying thrombocytopenia in HS remains unknown. It is not known whether NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome is activated in HS platelet, which, in turn, induces platelet activation and thrombocytopenia. This study tried to clarify the activation of the NOD-like receptor signaling pathway under HS conditions and investigate its roles in mediating HS-induced thrombocytopenia. Methods Rat HS models were established in a certain ambient temperature and humidity. Platelets, isolated from blood, were counted and CD62P, an index of platelet activation, was measured by flow cytometry in all rats. The colocalization of NLRP3 inflammasome in platelet was detected by confocal fluorescence microscopy. Mitochondrial-derived reactive oxygen species (ROS) was detected using the molecular probes. Plasma HMGB1 and IL-1β levels were measured by ELISA. Results Platelet activation, showed by upregulated CD62P, and thrombocytopenia were observed in HS rats. HS activated the NLRP3 inflammasome, which was induced by elevated levels of ROS, while the upregulated CD62P and thrombocytopenia triggered by NLRP3 inflammasome were attributed to the high mobility group box protein 1 (HMGB1) inplasma. Moreover, inhibition of the NOD-like receptor signaling pathway in rats with HS suppressed platelet activation and the decline of platelet count. Similar results were obtained when the receptor toll-like receptor 4 (TLR4)/advanced glycation end product (RAGE) was blocked. Conclusions The NOD-like receptor signaling pathway induces platelet activation and thrombocytopenia in HS rats. These findings suggested that the NLRP3 inflammasome might be the potential target for HS treatment.

The changes of porosity and microcracks of high-temperature granite under water-cooling have a great influence on the safety and efficiency of geothermal resources exploitation. To analyze the formation conditions of the pore structure and microcracks of granite specimens at different temperatures under water-cooling, the rock porosity was measured by NMR, and the rock microstructure was observed by PM and SEM. The results show that the closure of microcracks occurs at 150 °C and the grain boundary microcracks appear at 300 °C. And the porosity and pore size begin to increase, the number of pores remains stable, and intracrystalline microcracks appear at 450 °C. When T = 600 °C, macropores and trans-granular microcracks appear inside the rock. When 600 °C

The formation energy of an oxygen vacancy and the diffusion barrier of an oxygen ion have a significant impact on the operating voltage and other parameters of resistive random access memory. In this research, n-type dopants and p-type dopants were, respectively, used to make comparative research on the formation energy of the oxygen vacancy and the diffusion barrier of the oxygen ion in orthorhombic λ-Ta2O5 taking first-principles methods. The band unfolding calculation results show that the donor level and acceptor level are, respectively, formed in the bandgap after the doping of W and Al. After the doping of Al, the formation energy of the oxygen vacancy decreases as the doping concentration increases. Instead, after the doping of W, the formation energy of the oxygen vacancy only undergoes an increase of 0.2 eV, and the diffusion barrier increases first and then decreases with the increase in the concentration of the doped W. After the doping of Al and W, the diffusion barriers of oxygen ions change within the ranges of 0.3–1.6 and 0.12–1.23 eV, respectively.

The multiple-input multiple-output (MIMO) radar imaging technology has attracted many scholars due to its many inherent advantages, such as avoiding complex motion compensation and imaging a quickly maneuvering target, compared to inverse synthetic aperture radar (ISAR) imaging. Although some imaging algorithms, such as the 2D fast iterative shrinkage thresholding algorithm (2D-FISTA), can meet the demand for super-resolution, they are not directly suited to MIMO radar imaging, for which the MIMO manifold needs to be considered. In this paper, based on the above questions, we propose the MIMO radar imaging algorithm, utilizing the sparsity of the scattering map in space and the MIMO array manifold, even achieving a good performance in the presence of MIMO channel error. The sparse reconstruction algorithm is developed with the alternative direction method of multipliers (ADMM) with the help of 2D-FISTA and the lp-norm. Then, two algorithms are derived: one is the exact sparse recovery algorithm, and the other is the inexact sparse recovery algorithm. Although the exact sparse recovery algorithm can converge to a more accurate precision than the inexact algorithm, the latter can converge at a faster speed. Finally, the results on simulation data validated the effectiveness of the algorithm.

The instability of rock engineering is normally dominated by the shear failure of rock mass. The dip angle of discontinuous planes widely existing in rock mass is a key parameter affecting the shear strength and failure mode of jointed rock. This paper aims to investigate the influence of discontinuous joints on the shear failure of rock. Direct shear tests are carried out on rock-like specimens with discontinuous joints in different dip angles. During the shear tests, the strain field is monitored in real-time by digital image correction (DIC) technology. Experimental results show that the shear strength, shear strain evolution, and failure mode for the jointed specimens are affected by the dip angles of the discontinuous joints. The maximum shear strain of specimens with joint angles of 45° and 75° increases gradually with the increase of shear loading. The maximum shear strain for the specimens with joint angles of 0°, 15°, 30°, 60°, and 90° increases sharply after the shear load reaches 80% of the peak load. When the joint inclination angle is less than 45°, the crack begins to expand from the joint tip and is interconnected to form a penetrating fracture. When the joint dip angle is greater than 45°, the cracks initiate at the joint tip and then propagate at different paths resulting in multistage shearing and crushing failure.

To explore the fracture mechanism of surrounding rock for thermal-mechanical coupling in deep mining, the theoretical solution of the internal temperature and stress evolution of the underground chamber cold boundary subjected to cold impact was obtained by thermoelastic theory. The conduction law of temperature and the evolution characteristics of stress were studied by theoretical formulas, and the influence of the convective heat transfer coefficient on the rate of tensile stress reduction was analyzed. The results show that the theoretical solution is in good agreement with the field measured value, which proves that the theoretical calculation method adopted in this paper is reliable and accurate. When the surface of the underground chamber is impacted by the change of temperature, the cold boundary temperature drops sharply at first, then gradually slows down, and finally reaches the same temperature as the air; the tensile stress decreases sharply from the initial high-stress value, then gradually decreases, and finally tends to be stable. The effects of different convective heat transfer coefficients on the change of temperature resistance of rocks were considered by numerical simulation. The numerical simulation results show that increasing the convective heat transfer coefficient not only increases the tensile stress of the heat transfer boundary but also increases the possibility of cracks, which makes the rock easier to crack. Based on the research results, we introduced the thermal-mechanical coupling disturbance range coefficient β = L/2D (β = 6–8) and proposed that the convective heat transfer coefficient is the reference index of the deep mining support structure, which can provide a theoretical basis and technical support for the selection of support materials.

For the development of deep resources, the temperature field of deep rock mass is an unavoidable problem. In order to understand the law of redistribution of temperature field in deep rock mass disturbed by fissure water, this paper simulates the heat transfer process of smooth and rough fractured rock mass with groundwater flow, and analyzes the influence of fracture opening, seepage velocity and roughness on the redistribution of temperature field. The results show that: the larger the fracture opening is, the smaller the growth rate of rock wall temperature is, and the larger the range of slow increase is of water temperature; seepage velocity has a gradual effect on the increase of rock wall temperature, the greater the seepage speed is, the smaller the water temperature is at the same position; when the roughness is between 0% and 20%, the rock wall temperature has a sudden drop, and the maximum rock wall temperature decreases by 20.56%. Compared with the flow velocity, changing the fracture roughness can improve the cooling efficiency of rock wall. With the increase of roughness, the water temperature in the same position is lower.

Engineering rock mass is normally subject to cyclic–dynamic disturbances from excavation, blasting, drilling, and earthquakes. Natural fractures in rock masses can be reactivated and propagated under dynamic and static loadings, which affects the stability of rock mass engineering. However, fractured rock mass failure induced by cyclic-impact disturbances is far from clear, especially considering varying angles between the rock mass and the direction of impact loadings. This work investigated rock deformation and failure characteristics through cyclic impact tests on granite samples with cracks of different angles. A Hopkinson bar was employed for uniaxial cyclic impact tests on granite samples with the crack inclination angles of 0–90°. The magnetic resonance imaging technique was used to determine rocks’ porosity after cyclic impacts. The stress–strain curves, porosity, strength, deformation modulus, failure modes, and energy density of samples were obtained and discussed. Results showed that the crack inclination angles significantly affected the damage evolution and crack morphology of rocks. Under the constant cyclic impact, the dynamic deformation modulus and dynamic strength of rock samples first increased and then decreased with the increase in crack inclination angle. The failures of granite samples for inclination angles of 0 and 90° were dominated by tensile cracking, while those for the inclination angles of 30–60° were dominated by shear cracking. The energy density per unit time gradually decreased with the increase in impact cycles. The results can provide references for the stability analysis and cyclic-impact-induced failure prediction of fractured rock masses.

A complex-function fluid controller placed in front of a membrane module was used to control the velocity change with feed fluid and reduce membrane fouling. Using humic acid as the simulated pollutant, the effects of the square wave function, sine function, reciprocal function, and power function feeding on the membrane flux were investigated. For sine function feeding, the membrane-specific flux was the largest and was maintained above 0.85 under the intermittent frequency of 9 s. Compared with the final membrane-specific flux with steady-flow feeding of 0.55, functional feeding could significantly reduce membrane fouling. SEM results showed that sine feeding led to slight contamination on the membrane surface. Furthermore, the Computational Fluid Dynamics (CFD) simulation results showed that the shear force of sine function feeding was about three times that of the steady flow (6 × 105 N). Compared with steady feeding, functional feeding could significantly improve the shear force on the membrane surface and reduce membrane fouling.

The incidence and mortality of sepsis in the intensive care unit (ICU) are extremely high. Thrombocytopenia, one of the most common laboratory abnormalities, is correlated with prognosis in sepsis. The pathophysiology of sepsis-associated thrombocytopenia (SAT) remains unclear and may be associated with several factors such as platelet activation due to vascular injury and pathogen, suppression of bone marrow, platelet-targeted antibodies and desialylation. This review summarized all these possible mechanisms in the 3 subtypes of SAT: increased platelet consumption, reduced platelet production and increased platelet destruction. Based on the clinically available platelet parameters, the evidence for identifying SAT subtypes and the recent progress in treatments according to these subtypes are proposed to provide new prospects for the management of SAT.

To investigate the effects of offset notch on the fracture properties of rock beam under bending load, granite beam specimens with “one single offset notch” and “central and offset double notches” are made. A series of three-point bending beam tests on the specimens are carried out by controlling the displacement rate of central notch. The whole load-displacement (P-CMOD) curves are obtained. Experimental results show that the larger the distance between the offset notch and beam central is, the larger are the peak load and nominal strength of the specimen. The peak load and nominal strength for the “central and offset double notches” specimens are both larger than those for the “single central notch” specimen. A fracture model considering the effect of offset notch is developed, and the relationship between the offset notch parameter, tensile strength, and fracture toughness is established.

According to the strain-softening characteristics of rock mass, an ideal elastic strain-softening model is developed, and the surrounding rock of tunnels is subdivided into the plastic broken zone, plastic strain-softening zone, and elastic zone. Based on the generalized spatially mobilized plane criterion, an elastic-plastic analytical solution of a circular tunnel is derived. The effects of intermediate principal stress, strain softening, and dilatancy are considered in the unified solution. The stress, displacement, and plastic zone radius of surrounding rock based on the SMP criterion are compared with those based on the Mohr–Coulomb criterion. Furthermore, the effects of parameters such as the softening modulus, dilatancy angle, and internal friction angle on the deformation and stress of tunnels are discussed. It has been found that the larger the dilatancy angle is, the larger the plastic zone displacement and the radius of the broken zone are. The larger the internal friction angle, the smaller the sizes of the plastic zone, the strain-softening zone, and the broken zone are. The deformation of surrounding rock in the broken zone is more sensitive to the internal friction angle than that in the strain-softening zone. The unified solution based on the SMP criterion provides a well understanding for the elastic-plastic state of tunnels, which can be the guidance for tunnel excavations and support designs.