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Abstract: To assess the effects of nitrogen (N) deposition on greenhouse gas (GHG) fluxes in alpine grassland of the Tianshan Mountains in central Asia, CH4, CO2 and N2O fluxes were measured from June 2010 to May 2011. Nitrogen deposition tended to significantly increase CH4 uptake, CO2 and N2O emissions at sites receiving N addition compared with those at site without N addition during the growing season, but no significant differences were found for all sites outside the growing season. Air temperature, soil temperature and water content were the important factors that influence CO2 and N2O emissions at year-round scale, indicating that increased temperature and precipitation in the future will exert greater impacts on CO2 and N2O emissions in the alpine grassland. In addition, plant coverage in July was also positively correlated with CO2 and N2O emissions under elevated N deposition rates. The present study will deepen our understanding of N deposition impacts on GHG balance in the alpine grassland ecosystem, and help us assess the global N effects, parameterize Earth System models and inform decision makers. [Copyright &y& Elsevier]

Abstract: In order to figure out the effect of the initial pH of solutions on electrochemical oxidation, a commercial dimensionally stable anode (DSA) was employed for degradation of organic pollutants tetracycline and Orange II. It was observed that the process of electrochemical oxidation was highly pH dependent in a wide pH range from pH 2.0 to 12.0. Acidic and alkaline conditions were found to be especially favorable for the organics oxidation, but the lowest decolorization efficiency and COD removal was proved to be at pH 7.0. The use of NaCl was more effective for organics degradation than Na2SO4 because chlorine and hypochlorite ions were generated and involved in oxidation process. The effect of solution pH was basically resulted from the generation of oxidizing species other than the electrostatic attraction, which can influence the adsorption of organic pollutants onto the anode to a large extent. [Copyright &y& Elsevier]

A heterostructure composed of ZIF-67-derived nitrogen and cobalt-doped carbon enfolded silicon (C@Si) nanoparticles anchored on 2D MXene layers was constructed for boosting the performance of lithium-ion batteries (LIBs). The heterostructure anode demonstrated a high initial discharge capacity of 3021 mA h g−1 at 0.2 A g−1, retaining outstanding cycling stability with a reversible capacity of 520 mA h g−1 at 2000 mA g−1, and the coulombic efficiency remained above 97% after 500 cycles. The introduced Ti3C2 nanosheets and the cobalt-doped carbon can not only contribute to the interfacial transfer of Li+ and electrons but also buffer the volume expansion of Si. [ABSTRACT FROM AUTHOR]

In order to address the issue of hole collapse, which frequently arises when boring piles are being constructed in intricate marine strata, this paper discusses the influence of the slurry ratio on the slurry performance as well as the mechanism of slurry wall protection. It performs this by means of theoretical analysis, laboratory ratio testing, engineering analogies, numerical simulation, and field testing. Our findings demonstrate that adding sodium polyacrylate and sodium carboxymethyl cellulose can enhance mud's viscosity, contribute to flocculation, and improve the connection between mud and soil layers. Refering similar engineering cases, three optimization schemes are proposed for achieving a mud ratio that offers wall protection in complex marine strata. Furthermore, the particle flow model of slurry viscous fluid is established. The collapse of holes in the sand layer is reflected in the uneven radial displacement of hole walls and the invasion of mud particles. Increasing the viscosity of mud gradually transforms the uneven radial deformation of pore walls in the sand layer into a uniform radial deformation, whereas increasing the proportion of mud significantly decreases the radial displacement of hole walls. Additionally, when the mud pressure in the hole is 300 kPa and 600 kPa, the wall protection effect is better, and there is no particle penetration by substances such as sand. It is found that a high mud pressure can promote the diffusion of mud particles into the sand layer, while low mud pressure cannot balance the pressure on deep soil. The results of the field tests show that the ratio of water–clay–bentonite–CMC-Na–sodium carbonate = 700:110:90:1.5:0.5 used (where the mass percentage of each material is 77.8% water, 12.2% clay, 10% bentonite, 0.16% CMC-Na, and 0.05% sodium carbonate) can effectively prevent hole collapse and reduce the thickness of the sand layer at the bottom of the hole by 50%. [ABSTRACT FROM AUTHOR]

To better understand the influence of edge flaws on the fracture behaviors of central-flawed specimens, a series of uniaxial compression tests were carried out on the central-flawed rock-like specimens with two edge flaws using a servo-controlled testing apparatus. Two edge flaws were divided into coplanar and non-coplanar distribution (F-L1 and F-L2). The acoustic emission, digital image correlation and high precision video were applied simultaneously to monitor the internal AE signals, surface strain, and crack propagation of rock-like materials, respectively. The results show that the degradation effect of non-coplanar edge flaws on the peak strength, elastic modulus, and crack initiation angle are more significant than that of coplanar edge flaws. When the inclination angle of the central flaw increases from 15° to 60°, the peak strength, elastic modulus, and crack initiation angle decrease. In contrast, the complete initiation angle, total energy density, and accumulated acoustic emission energy first decrease and then increase. The acoustic emission counts and acoustic emission accumulated energy occur a sudden increase when the rock-like specimen deforms into the next stage. Moreover, central flaw controls the initiation of new cracks, whereas edge flaws influence the propagation trajectories of new cracks. Furthermore, the coalescence between the central and edge flaws in the F-L2 specimen is easier to happen than that in the F-L1 specimen. [ABSTRACT FROM AUTHOR]

Aims: Drought significantly impacts ecosystem structure and function, especially the transformation rates of soil carbon and nitrogen. This study explores how drought affects ecosystem respiration (Re), methane (CH4) uptake and nitrous oxide (N2O) emissions in temperate desert steppes and the underlying mechanisms. Methods: An in-situ experiment was conducted in the Inner Mongolia desert steppe in northern China to study the effect of drought on Re, CH4 and N2O fluxes. Structural equation modeling (SEM) was used to establish the relationship between Re, CH4 uptake and N2O emissions and plant functional traits and environmental factors. Results: Ecosystem respiration and CH4 uptake were both significantly reduced by chronic drought (66 % precipitation reduction from 1 May to 31 August) but not by pulse drought (100 % precipitation reduction in June and July). In contrast, no significant impact on N2O emissions was observed under chronic or pulse drought. There were no significant direct effects of soil moisture on Re, CH4 uptake or N2O emissions. However, soil moisture had an important indirect effect on Re, CH4 uptake and N2O emissions, mainly through its influence on plant functional traits, plant above-ground biomass and soil nutrients. Plant biomass and soil temperature were the key indicators of Re, and plant leaf nitrogen content was the key plant trait associated with N2O emissions. In contrast, plant specific leaf area and biomass were the key traits associated with CH4 uptake. Conclusions: Overall, Re and CH4 uptake were reduced by chronic drought in this desert steppe, but there was no significant effect on N2O emissions. Ecosystem respiration, CH4 uptake and N2O emissions were associated with plant functional traits. This provides new insight for the understanding of soil carbon and nitrogen dynamics in desert steppe systems under drought conditions and an important theoretical basis for the revision of model parameters. [ABSTRACT FROM AUTHOR]

White coat pigmentation is a striking phenotype of many domesticated species and has various genetic controls. The Tianzhu White yak, an indigenous breed with a complete white coat, has fascinated Tibetans for centuries. However, the genetic basis of this trait remains unknown. Here, we conducted population genomics analysis and genome‐wide association study based on the whole‐genome sequencing data of 38 white and 59 non‐white‐coated yak. The results revealed the presence of KIT‐linked Cs alleles characterized by the translocations between chromosomes 6 and 29 in all‐white yak. Furthermore, structural variations showed additional duplications of the Cs alleles in white yak compared with colour‐sidedness cattle. Interestingly, the Cs alleles associated with the white coat phenotype in yak were found to have introgressed from taurine cattle. Our findings unveil the shared genetic control of the white coat phenotype and its evolution in closely related bovine species. [ABSTRACT FROM AUTHOR]

In order to study the changes in invasive plant population characteristics under different nutrient addition treatments, this study used the native invasive species Pedicularis kansuensis, which is spreading in the Bayabulak alpine grassland, as the research object and conducted two consecutive years of field studies in which nutrients were added to plots. Changes in the P. kansuensis population's invasive characteristics were monitored in 2020 and 2021 in four different nutrient-addition treatments, namely no-nutrients (control), low-nitrogen, high-nitrogen, and phosphorus treatments. The result showed that (1) nutrient addition had significant effects on P. kansuensis height and root/shoot ratio (p < 0.05); the time effect had significant effects on P. kansuensis height, coverage, abundance, aboveground biomass, and belowground biomass (p < 0.01), and the interaction between nutrient addition and time had a significant effect on P. kansuensis height (p < 0.01). (2) Nitrogen addition effectively inhibited the growth and the development of P. kansuensis, especially under high-nitrogen conditions in the second growing season, where the effect of height (2.50 cm), coverage (0.13%), richness (3 strains), aboveground biomass (0.21 g m−2), and belowground biomass (0.03 g m−2) was significant, with the P. kansuensis population almost disappearing by the end of the trial. (3) Phosphorus addition had no significant effect on the P. kansuensis population's invasive characteristics. These results indicate that higher nitrogen addition could effectively slow the invasion of the P. kansuensis population, and the findings of this study could provide certain baseline data and scientific guidance for the effective control of the P. kansuensis invasion of the Bayabulak alpine grassland in the future as well as identify certain theoretical bases for the effect of nutrient addition on invasive plants overall. [ABSTRACT FROM AUTHOR]

• A mixed mode I/III loading test was conducted on thermal damage ENDB granite. • The peak frequency signal of the sample is distributed between 80 kHz and 400 kHz. • A zero-frequency signal have an early warning effect on rock failure. • Proposed an acoustic early warning index based on critical slowing down theory. To explore the fracture morphology and acoustic emission characteristics of thermally damaged granite under mixed mode I/III loading, a series of heat treatment and mixed mode I/III loading tests were conducted on edge-notched disc bend (ENDB) granite samples. First, the thermal damage samples' strength and crack opening displacement were analyzed. Subsequently, based on 3D laser scanning technology, the fracture morphology of the sample was studied, and the fractal dimension was calculated. Then, the samples' acoustic emission characteristics were discussed, including the ringing count, b value, spectrum signature, and AF-RA. Finally, an acoustic early warning index was proposed based on the critical slowing down theory, and the influence of temperature on the early warning effect was analyzed. The results show that under mixed mode I/III loading, the samples formed an antisymmetric curved surface with out-of-plane torsion. As the thermal damage effect is enhanced, the peak strength decreases linearly, and the fractal dimension increases linearly. The failure mode changes from sudden instability to progressive instability. Shear cracks gradually dominate the sample failure. The peak frequency signal of the sample is mainly distributed between 80 kHz and 400 kHz. The appearance of the sudden drop in the b value and a zero-frequency signal has an early warning effect. The quadratic function can describe the relationship between warning time and temperature. As the temperature increases, the deterioration effect of historical loading on the sample is enhanced, the development time of sample failure is prolonged, and the early warning effect is better. [ABSTRACT FROM AUTHOR]

• The effects of high temperature and cyclic load on red sandstone were investigated. • The failure process of the specimen was analyzed in depth by AE and DIC technologies. • A crack classification model based on K-medoids and SVM algorithms was proposed. • The failure precursor characteristics were discussed by critical slowing down theory. This paper investigated red sandstone's acoustic emission (AE) and fracture characteristics under high temperature and cyclic load. The specimen's behavior throughout the process from stabilization to failure was systematically analyzed in terms of the distribution of AE activities, rupture scale, crack type, crack evolution, and failure mode. A crack classification model based on K-medoids and support vector machine (SVM) algorithms was proposed, and the optimal dividing line for tensile-shear cracks at different temperatures was determined as AF = 0.335 × R A + 76.890. The specimen's failure precursor information was recognized based on the critical slowing down theory. [ABSTRACT FROM AUTHOR]

Aims: Litter decomposition is a crucial component of nutrient recycling. Short-term nitrogen (N) deposition has been shown to influence litter decomposition in temperate steppe with significant variability due to differences in atmospheric N deposition, species identity, and experimental duration. Therefore, the effect of N addition, especially long-term, on litter decomposition in alpine grassland still needs further investigation. Methods: To address these knowledge gaps, we examined the influence of long-term N addition on litter decomposition, taking advantage of a field experiment with five N addition levels (0, 10, 30, 90, and 150 kg N ha−1 yr−1) with a meta-analysis, which has been running for 11 years in an alpine grassland, Northwest China. Results: Long-term N addition consistently decreased litter decomposition rates, and N negative effect became stronger with the increasing N addition rates. Reduced litter decomposition rates were related to lower soil enzymes activities. Litter decomposition rates were strongly correlated with litter quality, but weakly correlated with soil quality, but which suggested that litter quality and soil quality played important role in regulating litter decomposition. Furthermore, a regional meta-analysis revealed that N addition accelerated litter decomposition when all data were averaged. Although N addition indirectly increased litter decomposition, it had no direct effect on decomposition. However, the direction and degree of the direct effect of N on litter decomposition were regulated by N addition rate, experimental duration and form of N fertilizer. Conclusions: Overall, these results demonstrated that long-term N addition decreased litter decomposition and N negative effect increased over time. [ABSTRACT FROM AUTHOR]

• Experimental tests were conducted to investigate the Mode III fracture behaviour of transversely isotropic rock specimens. • The fracture process of the transversely isotropic rock specimens under pure Mode III loading was revealed from the microscopic view. • The effect of stratification plane parameters on the fracture behaviour of specimens under pure Mode III loading has been analyzed. The fracture behaviour in transversely isotropic rocks is significantly affected by stratification planes. In this paper, experimental tests were carried out using edge-notched disc bending (ENDB) specimens with different stratification plane inclination angles to investigate the fracture characteristics of transversely isotropic rocks under pure mode III loading. The influence of stratification plane inclination fracture toughness and fracture pattern were also analysed. An effective numerical model for ENDB specimens was established to simulate and analyse the microscale fracture process under pure mode III loading in PFC3D, and flat-joint contact (FJC) and smooth-joint contact (SJC) were used to simulate the rock matrix and stratification, respectively. The simulation results showed that the fracture plane development trend of specimens with different inclinations is different. For the specimens with stratification plane inclinations of 0°, 15°, 75° and 90°, the cracks at both ends of the prefabricated notch develop symmetrically. However, for specimens with inclinations of 30° and 60°, the propagation behaviour along the stratification plane occurs prior to cutting the stratification planes. In addition, higher stratification plane strength and wider spacing lead to higher peak loads. The fracture trajectory extends along the stratification plane more obviously with the decrease in the stratification plane strength, and the development degree of the fracture trajectory along the stratification plane decreases with the decrease in the stratification plane spacing. [ABSTRACT FROM AUTHOR]

• Physical models containing flaws and tubes are made by high-strength gypsum. • Fracturing characteristic of physical models are obtained from experimental tests. • The cracking mechanism of lining structure around tunnel is proposed. • Stress distribution and displacement field explain failure characteristic of model. The diverse joint distributions in natural layered rock masses bring a great difficulty to the study on fracturing characteristics of surrounding rock in the process of tunnel excavation. The joint angle plays a vital role in the fracturing behaviors of tunnels. In this paper, taking the shallow-buried tunnel in layered rock masses as the background, a series of uniaxial compression tests were performed on the physical models containing joints and tubes made of high-strength gypsum. The fracturing characteristics of models with joints of different combinations are obtained, and the cracking mechanism of lining structure is further explored. Furthermore, the influences of linings on the stress distribution in surrounding rock and lining around tunnel and the displacement field in the model are investigated by a particle-based discrete element method. The supporting effect of lining on the stability of tunnels is finally evaluated. [ABSTRACT FROM AUTHOR]

Desert soils are a significant global sink for methane (CH4). However, it remains unclear how CH4 uptake in temperate deserts could respond to elevated precipitation, nitrogen (N) deposition and warming. An in situ field experiment was conducted to investigate these effects on CH4 uptake in the Gurbantunggut Desert, northwest China, from September 2014 to August 2017. This desert was a weak sink for CH4 (0.83 kg C ha−1 year−1) over this period, with the non-growing season (November–March) accounting for 30.5% of the annual CH4 uptake. Pulse CH4 uptake was found to result from increased water addition (by 30% or 60 mm year−1) and low N deposition (30 kg N ha−1 year−1) which enhanced annual CH4 uptake by 62.3 and 52.6%, respectively. However, no significant impact of high N deposition (60 kg N ha−1 year−1) was found. Warming in open topped chambers (OTCs) had a variable effect on CH4 uptake, which mainly depended on variation in soil moisture. The response in CH4 uptake to the interaction between water and N addition was less than that for the individual factors, except under conditions of warming. In addition, CH4 uptake was significantly positively correlated to water-filled pore space (WFPS), differing from observations in forest and grassland ecosystems. Structural equation modeling indicated that CH4 uptake was significantly enhanced by soil moisture and the underground biomass of ephemerals. Overall, the CH4 sink of this desert was significantly enhanced by increasing precipitation and low N deposition, rather than warming, which may become a feedback for future climate. [ABSTRACT FROM AUTHOR]

In this paper, a new formulation of three-dimensional spherical discontinuous deformation analysis (DDA) based on second-order cone programming has been proposed. Artificial springs with open-close iteration used in classic DDA have been removed, given that improper stiffness parameters might cause numerical problems. Furthermore, to account for irregular granular shapes, a rolling resistance model is incorporated in the variational formulation. The proposed formulation can be cast into a standard second-order cone programming program, which can be solved using efficient off-the-shelf optimisation solvers. The proposed approach is validated by a series of numerical examples. [ABSTRACT FROM AUTHOR]

• Pure mode III fracture test on ENDB granite specimens after thermal shock. • 3D laser scanning technology is used to analyses the fracture morphology of rocks. • AH, SA, fractal dimension and JRC are used to describe the fractal characteristics. • The effect of temperature on rock fracture is studied from 25 °C to 625 °C. • Thermal shock above 525℃ can change the fracture mode of rocks. To investigate the effect of temperature on the pure mode III fracture behavior and fracture morphology of granite after thermal shock, edge-notched disc bend granite specimens are selected for heat treatment and a series of fracture tests. Firstly, the effect of temperature on the macroscopic fracture behavior of the rock is analyzed regarding the physical and mechanical properties and fracture toughness. Then, the impact of temperature on the microscopic fracture morphology of the rocks is discussed based on a fractal theory using 3D laser scanning techniques. The results show that temperature affects the fracture behavior of rock by changing its physical parameters and mechanical properties. High temperatures can change the fracture mode of rocks and have a softening effect on rocks. The heat treatment temperature of 325 °C above can convert rocks from brittle to ductile failure. When the heat treatment temperature is above 525 °C can evolve rocks from pure mode III fracture to mixed mode I/III fracture. The fracture toughness of the rock and the joint roughness coefficient are highly linearly correlated with temperature. The fracture toughness of the rock decreases by 0.5 MPa∙m0.5, and the joint roughness coefficient increases by 1.7 for every 100 °C increase in temperature in the range of 25 °C to 625 °C. The asperity height and slope angle of the rock obey a normal distribution. The higher the temperature, the larger the fracture surface area, the larger the fractal dimension, the stronger the anisotropy of the surface protrusions, and the rougher the rock surface. [ABSTRACT FROM AUTHOR]

• Grazing and reclamation decreased the proportion of >2 mm aggregates and enhanced SOC stability. • Grazing enhanced the complexity of bacterial networks in >2 mm and <0.25 mm aggregates. • Grazing and reclamation shifts bacteria from variable selection to homogenizing dispersal. • Bacterial network and community assembly process were crucial in maintaining SOC stability. Grazing and reclamation are the major modulators of soil organic carbon (SOC) stability in alpine steppes. However, our understanding of changes in SOC caused by grazing and reclamation at the aggregate scale is limited, and the mediating role of microorganisms remains unclear. Here, based on a long-term observation transect, we selected three land-use types: a long-term enclosed natural steppe (NS), a grazed steppe (GS), and a steppe reclaimed as cropland (CL). We investigated the impacts of grazing and reclamation on soil aggregate distributions, SOC fractions and the microbial community, and microbial contributions to SOC stability. Overall, GS and CL significantly decreased the proportion of >2 mm aggregates (by 32.25–33.72%), and enhanced SOC stability within different aggregate sizes, with the highest SOC stability observed in 0.25–2 mm and <0.25 mm sizes. GS significantly decreased bacterial diversity and increased the relative abundance of Gammaproteobacteria, while CL significantly increased microbial diversity and the relative abundance of Alphaproteobacteria. Importantly, GS enhanced the complexity of the bacterial OTUs networks in >2 mm and <0.25 mm aggregates. GS and CL caused changes in the assembly processes of bacterial communities, shifting from being mainly controlled by variable selection to being mainly controlled by homogenizing dispersal. However, there were only minor differences observed in the microbial community assembly within different aggregate sizes under the same treatment. Random forest models and correlation analysis revealed that the bacterial community, especially the network patterns and community assembly, was a key determinant of SOC stability in soil aggregates. In conclusion, we emphasize the important contribution of soil bacterial network patterns and community assembly to SOC stability in the context of human activities, providing information that may be useful for developing alpine steppe management strategies to enhance soil carbon sequestration. [ABSTRACT FROM AUTHOR]

• Soil carbon sequestration was significantly increased by long-term N addition. • NECB and NGWP were significantly reduced by long-term N addition. • The offset effect of N 2 O emissions to ecosystem C uptake was decreased by LN addition. Grassland systems are important terrestrial carbon sinks and have great potential for carbon (C) sequestration. Increased atmospheric nitrogen (N) deposition has profoundly affected C balance and greenhouse gas emissions in grassland systems. However, the effects of long-term nitrogen (LN) deposition on net ecosystem carbon budget (NECB) and net global warming potential (NGWP) in grassland systems are still not clearly understood. A field experiment was conducted to test the effect of LN addition (0, 30, 60, 120 and 240 kg N ha−1 yr−1) on NECB and NGWP in a temperate grassland area in Inner Mongolia, China. LN addition significantly increased soil organic carbon density (SOCD) and C sequestration in surface soil (0–30 cm) with the increase of N addition rate from 2005 to 2018. In contrast, a decrease in ecosystem respiration (R e) was observed, except at low LN concentration (30 kg N ha−1 yr−1). Annual N 2 O flux was significantly increased, and the CH 4 sink was significantly decreased by LN addition. NECB and NGWP were relatively weak in this temperate grassland, ranging from −627.29 ± 198.81 and −232.87 ± 23.11 kg CO 2 ha−1yr−1, respectively, and significantly decreased with increasing LN application. The offset effect of N 2 O emission to ecosystem C uptake decreased significantly with increased LN addition, and was stable at high LN addition. This was related to the increase in soil C sequestration due to plant C uptake. These results indicate that LN addition significantly decreased the NECB and NGWP of this grassland. Increased long-term N deposition significantly enhanced soil C sequestration, which has important implications for mitigating climate warming. [ABSTRACT FROM AUTHOR]

Astragalus mongholicus Bunge (A.M.B), Potentilla anserina (A.P), Festuca ovina (F.O) The original article has been corrected. The original article can be found online at https://doi.org/10.1007/s11104-022-05537-8. [Extracted from the article]

• The red sandstone was tested under high temperature-cyclic load coupling. • The factors of limiting energy storage and dissipation were defined. • Coupling damage was determined based on Lemaitre strain equivalence hypothesis. • The thermal damage mechanism was revealed by XRD and TG-DSC techniques. In this paper, the fatigue characteristics of red sandstone after heat treatment were analyzed from the aspects of stress-strain curve, deformation, energy and damage. Furthermore, the thermal damage mechanism was discussed by X-ray diffraction and thermogravimetric-differential scanning calorimetry synchronous analysis tests. The results showed that 400 °C was the threshold temperature. Below this temperature, the brittleness, failure stress and stiffness of the specimen were enhanced. Otherwise, they were weakened. Mineral decomposition, dehydration and crystal expansion occurred during the heat treatment process. The thermal damage mechanism of red sandstone can be clarified by a competitive mechanism of strengthening and weakening effects. [ABSTRACT FROM AUTHOR]

• The Pd/SiO 2 catalysts with different Pd contents (Pd-0.16 wt%, 0.26 wt%, 0.52 wt%, 2.60 wt%) are prepared via sodium borohydride reduction. • Highly dispersed Pd nanoparticles are stably loaded on silica support with high specific surface area. • Pd/SiO 2 (0.26 wt%) shows good catalytic performance for selective hydrogenation of phenol under mild reaction conditions (conversion-80.6%, selectivity to cyclohexanone-92.1%, TOF-1106.1 h−1). • Pd/SiO 2 is also stable for phenol hydrogenation. Cyclohexanone is significant chemical reagent for organic synthesis, so it is key to design and prepare a highly active and environmentally friendly catalyst for the conversion of phenol to cyclohexanone. The results in this work show that the Pd-based supported nanocatalysts (Pd/SiO 2) with various Pd contents (Pd/SiO 2 –1 with 0.16 wt% Pd, Pd/SiO 2 –2 with 0.26 wt% Pd, Pd/SiO 2 –3 with 0.52 wt% Pd, Pd/SiO 2 –4 with 2.60 wt% Pd) have high conversion and selectivity in phenol selective hydrogenation to cyclohexanone under relatively moderate reaction parameters, Pd/SiO 2 –2 with the highest conversion of 80.6%, selectivity of 92.1% and turnover frequency (TOF) of 1106.1 h−1. This excellent activity is attributed to the highly dispersed Pd nanoparticles (NPs) on silica with high surface area. The Pd/SiO 2 catalysts are with high Pd dispersion and strong interaction of Pd-SiO 2 , which have been proved by XRD, XPS, BET, TEM, HRTEM, STEM, STEM-EDS elemental analysis techniques. The as-prepared materials have good catalytic behaviors in the selective hydrogenation of phenol and good stability, facilitating phenol hydrogenation to cyclohexanone and preventing the excessive hydrogenation of cyclohexanone to cyclohexanol. [Display omitted] [ABSTRACT FROM AUTHOR]

• The principal stress distribution surrounding the flaw and openings is derived. • The local stress evolution surrounding the flaw and opening is derived. • The slopes of stress evolution curves were computed and compared. Tunnel excavation changes the original stress state which directly leads to the surrounding rock fracture, many researches focus on the stress or displacement evaluation surrounding an opening or a tunnel. Flaws and openings dramatically change the state of internal stress within the rock mass, and the internal stress concentrates at some certain positions surrounding the opening. When the flaws and openings simultaneously exist, the internal stress interacts. To discuss about the stress evolution surrounding the flaw and opening, this study used the PFC program to establish numerical models containing one open flaw and two circular openings. Under uniaxial compression, the stress distributions surrounding the flaw and the openings at different loading stages and different flaw orientations were presented and the principal stress evolutions around the flaw and the openings were analyzed. The proposed numerical method in measuring local stress can be useful to evaluate the local stress distribution and evolution surrounding the flaw and opening. [ABSTRACT FROM AUTHOR]

• Compressive-shear tests were conducted on transversely isotropic rock with different inclinations. • The micro-scale fracturing process of transversely isotropic rock with different inclination are analyzed. • The effects of bedding plane strength and spacing are analyzed. The failure and mechanical behavior of transversely isotropic rock are significantly affected by the original bedding planes. Until now, few studies have been performed to investigate the influence of the geometrical and mechanical parameters of the bedding planes on the fracture characteristics of transversely isotropic rocks under planar shear fracture loading conditions. For this purpose, experimental and numerical compression-shear tests on double-notched specimens are conducted to investigate the fracturing characteristics of transversely isotropic rock under planar shear fracture loading. The experimental study that focuses on the influence of bedding plane inclination on fracture load, fracture pattern and AE evolution, and six inclination angles is conducted in this study. Based on the flat joint contact model (for the rock matrix) and smooth joint contact model (for the original bedding plane) in PFC2D (particle flow code), the microscale fracturing process of transversely isotropic rock with different inclinations is simulated and analyzed. The results show that the inclination has an important influence on the fracture load and fracture pattern, and the maximum and minimum fracture loads are obtained for specimens with inclination angles of 30° and 60°, respectively. Moreover, the strength and spacing of the original bedding planes also play an important role in fracture loads. Higher bedding plane strength and wider bedding plane spacing result in higher fracture loads. In addition, with a moderate inclination angle, transversely isotropic rock with higher bedding plane strength tends to form cracks that cut through the rock matrix. However, with the decrease in the bedding plane strength, more fractures form along the bedding planes. [ABSTRACT FROM AUTHOR]

• Atmospheric N deposition in China was evaluated by two time-scale deposition databases. • Bulk and dry N deposition reached a peak between 2000 and 2010 and then began a steady decline. • Significant decrease of oxidized N deposition proved the effectiveness of NO x emissions control. • Increase of NH 3 dry deposition highlighted the importance of regional NH 3 mitigation. China has experienced a dramatic change in atmospheric reactive nitrogen (Nr) emissions over the past four decades. However, it remains unclear how nitrogen (N) deposition has responded to increases and/or decreases in Nr emissions. This study quantitatively assesses temporal and spatial variations in measurements of bulk and calculated dry N deposition in China from 1980 to 2018. A long-term database (1980–2018) shows that bulk N deposition peaked in around 2000, and had declined by 45% by 2016–2018. Recent bulk and dry N deposition (based on monitoring from 2011 to 2018) decreased from 2011 to 2018, with current average values of 19.4 ± 0.8 and 20.6 ± 0.4 kg N ha−1 yr−1, respectively. Oxidized N deposition, especially dry deposition, decreased after 2010 due to NO x emission controls. In contrast, reduced N deposition was approximately constant, with reductions in bulk NH 4 +-N deposition offset by a continuous increase in dry NH 3 deposition. Elevated NH 3 concentrations were found at nationwide monitoring sites even at urban sites, suggesting a strong influence of both agricultural and non-agricultural sources. Current emission controls are reducing Nr emissions and deposition but further mitigation measures are needed, especially of NH 3 , built on broader regional emission control strategies. [ABSTRACT FROM AUTHOR]

Nitrous oxide (N 2 O) is the third most important greenhouse gas, and can damage the atmospheric ozone layer, with associated threats to terrestrial ecosystems. However, to date it is unclear how extreme precipitation and nitrogen (N) input will affect N 2 O emissions in temperate desert steppe ecosystems. Therefore, we conducted an in-situ in a temperate desert steppe in the northwest of Inner Mongolia, China between 2018 and 2021, in which N inputs were combined with natural extreme precipitation events, with the aim of better understanding the mechanism of any interactive effects on N 2 O emission. The study result showed that N 2 O emission in this desert steppe was relatively small and did not show significant seasonal change. The annual N 2 O emission increased in a non-linear trend with increasing N input, with a much greater effect of N input in a wet year (2019) than in a dry year (2021). This was mainly due to the fact that the boost effect of high N input (on June 17 th 2019) on N 2 O emission was greatly amplified by nearly 17-46 times by an extreme precipitation event on June 24 th 2019. In contrast, this greatly promoting effect of high N input on N 2 O emission was not observed on September 26 th 2019 by a similar extreme precipitation event. Further analysis showed that soil NH 4 + -N content and the abundance of ammonia oxidizing bacteria (amoA (AOB)) were the most critical factors affecting N 2 O emission. Soil moisture played an important indirect role in regulating N 2 O emission, mainly by influencing the abundance of amoA (AOB) and de-nitrification functional microorganisms (nosZ gene). In conclusion, the effect of extreme precipitation events on N 2 O emission was greatly increased by high N input. Furthermore, in this desert steppe, annual N 2 O flux is co-managed through soil nitrification substrate concentration (NH 4 + -N), the abundance of soil N transformation functional microorganisms and soil moisture. Overall, it was worth noting that an increase in extreme precipitation coupled with increasing N input may significantly increase future N 2 O emissions from desert steppes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Two-dimensional (2D) chromium-based self-intercalated materials Cr 1+ n X 2 (0 ≤ n ≤ 1, X = S, Se, Te) have attracted much attention because of their tunable magnetism with good environmental stability. Intriguingly, the magnetic and electrical properties of the materials can be effectively tuned by altering the coverage and spatial arrangement of the intercalated Cr (ic-Cr) within the van der Waals gap, contributing to different stoichiometries. Several different Cr 1+ n X 2 systems have been widely investigated recently; however, those with the same stoichiometric ratio (such as Cr 1.25 Te 2 ) were reported to exhibit disparate magnetic properties, which still lacks explanation. Therefore, a systematic in situ study of the mechanisms with microscopy techniques is in high demand to look into the origin of these discrepancies. Herein, 2D self-intercalated Cr 1+ n Se 2 nanoflakes were synthesized as a platform to conduct the characterization. Combining scanning transmission electron microscopy (STEM) and scanning tunneling microscopy (STM), we studied in depth the microscopic structure and local electronic properties of the Cr 1+ n Se 2 nanoflakes. The self-intercalation mechanism of ic-Cr and local stoichiometric-ratio variation in a Cr 1+ n Se 2 ultrathin nanoflake is clearly detected at the nanometer scale. Scanning tunneling spectroscopy (STS) measurements indicate that Cr 1.5 Se 2 /Cr 2 Se 2 and Cr 1.25 Se 2 exhibit conductive and semiconductive behaviors, respectively. The STM tip manipulation method is further applied to manipulate the microstructure of Cr 1+ n Se 2 , which successfully produces clean zigzag-type boundaries. Our systematic microscopy study paves the way for the in-depth study of the magnetic mechanism of 2D self-intercalated magnets at the nano/micro scale and the development of new magnetic and spintronic devices.

Background: High altitudes are characterized by low-pressure oxygen deprivation. This is further exacerbated with increasing altitude. High altitudes can be associated with reduced oxygenation, which in turn, can affect labor, as well as maternal and fetal outcomes. Epidural anesthesia can significantly relieve labor pain. This study aimed to assess the effects of elevation gradient changes at high altitude on the analgesic effect of epidural anesthesia, labor duration, and neonatal outcomes., Methods: We divided 211 women who received epidural anesthesia into groups according to varying elevation of their residence (76 in Xining City, mean altitude 2,200 m; 63 in Haibei Prefecture, mean altitude 3,655 m; and 72 in Yushu Prefecture, mean altitude 4,493 m). The analgesic effect was assessed using a visual analog scale (VAS). Labor duration was objectively recorded. The neonatal outcome was assessed using Apgar scores and fetal umbilical artery blood pH., Results: VAS scores among the three groups did not differ significantly ( p  > 0.05). The neonatal Apgar scores in descending order were: Xining group > Haibei group > Yushu group ( p  < 0.05). The stage of labor was similar among the three groups ( p  > 0.05). Fetal umbilical artery blood pH in descending order were: Xining group > Haibei group > Yushu group ( p  < 0.05)., Conclusion: Elevation gradient changes in highland areas did not affect the efficacy of epidural anesthesia or labor duration. However, neonatal outcomes were affected., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Wang, Li, Wu, Cheng, Zeng, Gao, Wang and Liu.)

2D transition metal dichalcogenides (TMDCs) are considered as promising materials in post-Moore technology. However, the low photoluminescence quantum yields (PLQY) and single carrier polarity due to the inevitable defects during material preparation are great obstacles to their practical applications. Here, an extraordinary defect engineering strategy is reported based on first-principles calculations and realize it experimentally on WS 2 monolayers by doping with IIIA atoms. The doped samples with large sizes possess both giant PLQY enhancement and effective carrier polarity modulation. Surprisingly, the high PL emission maintained even after one year under ambient environment. Moreover, the constructed p-n homojunctions shows high rectification ratio (≈2200), ultrafast response times and excellent stability. Meanwhile, the doping strategy is universally applicable to other TMDCs and dopants. This smart defect engineering strategy not only provides a general scheme to eliminate the negative influence of defects, but also utilize them to achieve desired optoelectronic properties for multifunctional applications., (© 2023 Wiley‐VCH GmbH.)