State Key Laboratory of Geohazard Prevention and Geoenvironment Protection

Renewable energy resources such as wind and solar are intermittent, which causes instability when being connected to utility grid of electricity. Compressed air energy storage (CAES) provides an economic and technical viable solution to this problem by utilizing subsurface rock cavern to store the electricity generated by renewable energy in the form of compressed air. Though CAES has been used for over three decades, it is only restricted to salt rock or aquifers for air tightness reason. In this paper, the technical feasibility of utilizing hard rock for CAES is investigated by using a coupled thermo‐hydro‐mechanical (THM) modelling of nonisothermal gas flow. Governing equations are derived from the rules of energy balance, mass balance, and static equilibrium. Cyclic volumetric mass source and heat source models are applied to simulate the gas injection and production. Evaluation is carried out for intact rock and rock with discrete crack, respectively. In both cases, the heat and pressure losses using air mass control and supplementary air injection are compared.

The current worldwide issue of fluoride contamination in groundwater has resulted in an increased demand for efficient adsorbents.

This paper presents an experimental study on the effect of randomly distributed fibres on enhancing the liquefaction resistance of sand. A series of undrained cyclic triaxial compression tests and hollow cylinder torsional shear tests were conducted on saturated sand samples with and without fibres. The influencing factors (including fibre length, fibre content and relative density), which are closely related to the liquefaction resistance of sand, were investigated. The test results indicated that samples reinforced with randomly distributed fibres can sustain many more loading cycles than can samples without fibres before liquefaction occurs; that is, the inclusion of fibres can effectively improve the liquefaction resistance of sand. The liquefaction resistance increased with increasing fibre length and fibre content. The reinforcement effect is found to be significant in both medium dense samples and loose samples. The results from triaxial tests and hollow cylinder shear tests were similar, indicating that the different loading conditions in the two types of tests will not influence the reinforcement effect of randomly distributed fibres.

Most landslides on the Loess Tableland (Shaanxi, China) are of the sliding-flow type, with long run-out distances. These landslides, which tend to be triggered by irrigation, result in loss of life and damage to infrastructure. In order to reveal the characteristics and mechanisms of sliding-flow landslides, field investigations, surveys and indoor tests, including consolidated undrained triaxial tests and ring-shear tests, were conducted. The apparent friction of sliding-flow loess landslides triggered by irrigation in the study area ranged from 0.01 to 0.25, with a mean of 0.159. These values are lower than those associated with the landslides triggered by the Wenchuan Earthquake. The deviation stress decreased to about 99% of its peak value, while the path of the effective stress revealed that the effective normal stress approached zero. Consequently, saturated loess samples were highly liquefiable under consolidated undrained triaxial tests. The pore pressures increased sharply and up to their peak value (mean of 130 kPa), corresponding to 92% of the applied normal stress. The path of effective stress did not reach the failure line. The loose structure and macro-pore content of loess provide the framework for static liquefaction to occur as a consequence of the generation of fine particles.

The synergistic coupling mechanism between magnetic and dielectric losses is widely recognized as a key design strategy for realizing efficient microwave attenuation composites. In this work, a carbon-based magnetic aerogel was successfully prepared using eggplant as a carbon source, realizing the interaction between magnetism and dielectric dissipation and developing a low-cost and environmentally friendly multifunctional material. The electromagnetic microwave absorption (EMA) characteristics were precisely tuned by varying the metal ion concentration ratio. Notably, the bimetallic ion-doped carbon aerogel has excellent EMA properties, with an EABmax of 6.32 GHz and RLmin value of −65.8 dB, under the condition of Fe3+ and Co2+ in a 1:2 molar proportion. This excellent performance is attributed to its unique three-dimensional (3D) carbon skeleton, in which the alloy nanoparticles are embedded in the hole-and-sheet structure and decorated on carbon, attaining optimal impedance alignment and enhanced wave dissipation performance. The combination of extremely low density and excellent compressive recovery properties, which can withstand multiple cycles of compression, has strongly advanced the field of biomass aerogels. This multifunctional aerogel material, which combines high EMA efficiency, environmental protection, low cost, thermal management, and compression resistance, has promising application in various electronic devices and military applications.

As an emerging technology, industrial Internet of Things (IIoT) connects massive sensors and actuators to empower industrial sectors being smart, autonomous, efficient, and safety. However, due the large number of build-in sensors of IIoT smart devices, the IIoT systems are vulnerable to side-channel attack. In this article, a novel side-channel-based passwords cracking system, namely MAGLeak, is proposed to recognize the victim's passwords by leveraging accelerometer, gyroscope, and magnetometer of IIoT touch-screen smart device. Specifically, an event-driven data collection method is proposed to ensure that the user's keystroke behavior can be reflected accurately by the obtained measurements of three sensors. Moreover, random forest algorithm is leveraged for the recognition module, followed by a data preprocessing process. Extensive experimental results demonstrate that MAGLeak achieves a high recognition accuracy under small training dataset, e.g., achieving recognition accuracy 98% of each single key for 2000 training samples.

A transition metal-free synthesis of <italic>N</italic>-(arylthio/seleno)ethyl sulfoxidmines <italic>via</italic> blue LED light-promoted radical sulfoximido-chalcogenization of aliphatic and aromatic alkenes was developed.

A new protocol was developed to synthesize (enantioenriched) thioethers and selenoethers from (chiral) benzylic trimethylammonium salts and di(hetero)aryl disulfides or diselenides. These syntheses were promoted by the presence of weak base and did not require the use of any transition metal, and resulted in the target products with good to excellent yields (72-94%). Using quaternary ammonium salts synthesized from enantiomerically enriched amines led to highly enantiopure benzylic thioethers and selenoethers (94-99% ee) with configurations reversed from those of their enantioenriched quaternary ammonium salts.

Glass fiber reinforced polymer (GFRP) materials are gaining increasing use in geotechnical engineering applications in recent years. The long-term performance of reinforced geostructures may be influenced by the rheological properties of GFRP soil nails or anchors. However, a clear understanding of this effect is lacking. This work aims to investigate the interaction between GFRP soil nail and sand under pullout conditions considering the time-dependent effect. A time-dependent model was proposed to describe the load–deformation characteristics of a GFRP soil nail during pullout. Laboratory pullout tests were performed using a load-controlled pullout apparatus to verify the effectiveness of the proposed model. Quasi-distributed fiber Bragg grating (FBG) optical fiber sensors were adhered on the pre-grooved GFRP soil nail to capture the variations of axial strain during testing. The test results are presented, interpreted, and discussed. It is shown that there is good agreement between the simulation results and the experimental data under low stress levels. Additionally, the impacts of model parameters on the predicted time-dependent pullout behavior of a GFRP soil nail were examined through parametric studies. The results indicate that the distributions of tensile force and GFRP–sand interfacial shear stress along the nail length are highly time dependent. The creep displacement of a GFRP soil nail is significantly influenced by the rheological parameters of the proposed model.

Pyrite (FeS2) is one of the most common hosts for gold (Au) in different types of gold deposits, including visible and invisible gold. For visible gold in pyrite, it remains unclear whether it resulted from remobilization of invisible gold in the gold-hosting pyrite or from external input. This paper reports a case study from the Zhaoxian gold deposit, which is the deep extension of the well-known Jiaojia gold deposit, in the Jiaodong gold province. The texture and composition of Au-bearing pyrite from the Zhaoxian deposit were studied with petrographic, Electron Back-Scattered Diffraction (EBSD) mapping, and Laser Ablation – Inductively Coupled Plasma – Mass Spectrometry (LA-ICP-MS) methods. Four types of pyrite (Py-1 to Py-4), corresponding to four generations of veins, i.e., the pre-ore V1, syn-ore V2 and V3, and post-ore V4, were distinguished. Py-2 is volumetrically the most abundant among the four, and is the main host of visible gold. LA-ICP-MS analyses of pyrite indicate that gold contents in most analysis points are below the detection limit, with measured Au contents ranging from 0.02 to 0.17 ppm (median 0.09 ppm) in Py-1, and 0.03 to 2.45 ppm (median 0.07 ppm) in Py-2. EBSD analyses indicate that pyrite (Py-2) display brittle deformation features including microstructures, lattice dislocation, and grain boundary displacement. Visible gold in Py-2 occurs in micro-fractures, cavities, and grain boundaries. The generally low contents of Au in pyrite, including Py-2, and the brittle deformation features, suggest that the visible gold grains did not result from remobilization of invisible gold from pyrite. Rather, the majority of gold was introduced by fluids after the formation of the gold-hosting pyrite. These fluids were derived from the same sources as those precipitating the gold-hosting pyrite, but were more evolved and enriched in Au. Circulation of these auriferous ore-forming fluids in microfractures of pyrite and interstitial space resulted in precipitation of visible gold.

In order to determine the mode-I (opening mode) dynamic fracture toughness of a rock, cracked-straight-through Brazilian disc (CSTBD) specimens with strain gauges glued on the specimen’s surface were diametrically impacted by a split Hopkinson pressure bar. A hybrid experimental-numerical approach was used to determine the dynamic initiation toughness, and it was also used in conjunction with a universal function to obtain the dynamic propagation toughness. Precautions were taken for getting the time history of dynamic stress intensity factors. Numerical accuracy, stability, and convergence to the solution were guaranteed by analyzing beforehand a widely-recognized benchmark dynamic crack problem. Using the numerical technique the result of the conducted trial analysis corresponded almost exactly with the classical result. The dynamic initiation toughness and dynamic propagation toughness of the rock increase with increasing dynamic loading rate and crack propagation speed, respectively, demonstrating the same variation tendencies reported in related literature. The present study shows that the experimental-numerical approach is both simple and effective.

BNO nanosheets could capacitively remove multiple metal ions from water due to their unique structural characteristics and coordination ability.

Seawater-based soybean-induced carbonate precipitation (SSICP) was proposed for sandy soil improvement. A series of comparative bio-cementation tests on Ottawa sand and sea sand through SSICP and deionized water-based soybean-induced carbonate precipitation (SICP) were carried out. Experimental results indicate that seawater can be used to extract soybean urease. It has a certain negative effect on urease activity, but SSICP method has better sand improvement performance. When the soybean powder concentration is 100 g/L and soaking time is 60 min, related urease activity exceeds 2.50 U. It increases as the soaking time increases before 60 min, and then decreases. Generally, urease activity of deionized water-extracted soybean urease is higher than that extracted by seawater. The compressive strength of SSICP bio-cemented Ottawa sand blocks reaches 401.67 kPa, which is about twice of that bio-cemented by SICP (191.62 kPa). The better sand improvement mechanism of the SSICP method can be attributed to the mixture of calcium carbonate and calcite magnesium produced by the SSICP process is beneficial to improve sand strength compared to calcite only produced by the SICP process. The performance of carbonate precipitation and bio-cementation on Ottawa sand is better than those on sea sand, resulting in lower compressive strength and carbonate content of sea sand blocks.

The ultimate particle size distribution of uniform and gap-graded soils is examined on specimens of carbonate sand that were subjected to large strains in a ring shear apparatus. The gap-graded soils were seen to retain a memory of their initial grading even at large strains. The particle size distributions were plotted in double logarithmic graphs either by mass or by number computed assuming different shapes. It was not possible to find linear subsets of the data, and since the samples were found experimentally to have converged to an ultimate grading, this suggests that the initial bimodal distribution prevented reaching an ultimate fractal distribution. Plots of the probability density functions of the particle sizes before and after shearing show the evolution of the gap-graded soils from a bimodal to a multi-modal distribution. This is accompanied by an evolution of the shape of the particles, visible in microphotographs and projections of the grains before and after test.

The study of digital elevation model (DEM) super-resolution reconstruction algorithms has solved the problem of the need for high-resolution DEMs. However, the DEM super-resolution reconstruction algorithm itself is an inverse problem, and making full use of the DEM a priori information is an effective way to solve this problem. In our work, a new DEM super-resolution reconstruction method is proposed based on the complementary relationship between internally learned super-resolution reconstruction methods and externally learned super-resolution reconstruction methods. The method is based on the presence of a large amount of repetitive information within the DEM. Using an internal learning approach to learn the internal prior of the DEM, a low-resolution dataset of the DEM rich in detailed features is generated, and based on this, the training of a constrained external learning network is constructed for the discrepancy data pair. Finally, it introduces residual learning based on the network model to accelerate the operation rate of the network and to solve the model degradation problem brought about by the deepening of the network. This enables the better transfer of learned detailed features in deeper network mappings, which in turn ensures accurate learning of the DEM prior information. The network utilizes the internal prior of the specific DEM as well as the external prior of the DEM dataset and achieves better super-resolution reconstruction results in the experimental results. The results of super-resolution reconstruction by the Bicubic method, Super-Resolution Convolutional Neural Networks (SRCNN), very deep convolutional networks (VDSR), ”Zero-Shot” Super-Resolution networks (ZSSR) and the new method in this paper were compared, and the average RMSE of the super-resolution reconstruction results of the five methods were 8.48 m, 8.30 m, 8.09 m, 7.02 m and 6.65 m, respectively. The mean elevation error at the same resolution is 21.6% better than that of the Bicubic method, 19.9% better than that of the SRCNN, 17.8% better than that of the VDSR method, and 5.3% better than that of the ZSSR method.

Test conditions, such as shearing rate and normal stress, have been long recognised as influencing the measured shear strength of clays and sands. However, their influence on composite soils, which have a wide range of particle sizes, has attracted much less attention from researchers. In this study, a total of 35 direct shear tests at different shearing rates under different normal stresses were conducted on specimens prepared by mixing different proportions of kaolin and glass beads. The changes in volume and water content of sheared specimens and the mesostructure of shear surfaces were studied. The results reveal a positive correlation between volume change and deviation of water content between the shear zone and outer zones, suggesting that the shear-induced volume change occurred primarily in the shear zones. Moreover, high normal stress and low shearing rate produced a relatively small void ratio in the shear zones, facilitating volumetric contraction of the specimen and the development of polished and evenly slickensided shear surfaces. In addition, the residual friction angle of the specimens tested was found to decrease with the increase in normal stress. The high shearing rate caused an increase in residual strength in specimens with low fines fraction, and reduced it in specimens with high fines fraction.

A recyclable Amberlyst-15-catalyzed three-component reaction in water was developed to synthesize asymmetric diarylmethyl sulfones in good to excellent yields with a wide substrate scope.

To address the challenges of low hydrogen peroxide utilization efficiency and excessive iron sludge accumulation in conventional Fenton processes, metal-free carbon cocatalysts harness their cost-effectiveness, ecofriendliness, and modifiable surface to propel green and enhanced Fenton chemistry. Their cocatalytic efficacy stems from structural features (pore architecture, hybridization state, and dimension) and surface properties (defect, heteroatom, functional group, graphitic structure, and site distribution), resulting in carbon cocatalysts playing multifaceted roles in assisting Fenton systems. This overview provides mechanistic insights into carbon cocatalyzed Fenton reactions, focusing on electron sources for iron reduction, and categorizes mechanisms into three approaches (electron donors, carbon-Fe(III) complexes, and electron mediators). Research studies have evolved from early-stage carbon cocatalysts for direct Fe(III) reduction to advanced systems utilizing coadsorbed pollutants or hydrogen peroxide as electron donors. Critical Fe(III)/Fe(II) cycles for sustainable Fenton oxidation are elucidated through electrochemical analysis, density functional theory calculations, and kinetics modeling. Multiple future strategies of carbon cocatalyzed Fenton processes for practical applications were proposed, including pretreating high-concentration refractory organic wastewater, post-treating persistent organic pollutants, and integrating enrichment techniques for trace pollutant removal with minimal chemical input. This review aims to deepen understanding and highlight application prospects of metal-free carbon cocatalyzed Fenton techniques for sustainable water remediation.

The Linfen–Yuncheng basin is an area prone to geological disasters, such as surface subsidence, ground fissuring, fault activity, and earthquakes. For the purpose of disaster prevention and mitigation, Interferometric Synthetic Aperture Radar (InSAR) was used to map ground deformation in this area. After the ground deformation characteristics over the Linfen–Yuncheng basin were obtained, the cross-correlations among regional ground subsidence, fault activity, and underground water level were analyzed in detail. Additionally, an area of abnormal deformation was found and examined. Through time series deformation monitoring and mechanism inversion, we found that the abnormal deformation was related mainly to excessive groundwater exploitation.

Ligand-free copper-catalyzed selective<italic>N</italic>-arylation of dinucleophiles including chiral α-amino amides with diaryliodonium salts as aryl electrophile equivalents was realized. Diaryliodonium salts prefer to react with dinucleophiles at the site of stronger basic amino groups.