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A series of red-luminescence bismuthate phosphors of double perovskite BaBiNaTeO6 doped with trivalent europium (Eu3+) were prepared by the solid-state diffusion method. The crystal structure and phase purity of the phosphors were analyzed. The photoluminescence (PL) properties of BaBiNaTeO6:Eu3+ were studied in detail. Upon blue light (466 nm) excitation, the powders showed brilliant red light at around 619 nm, and it was attributed to the electric dipole (ED) 5D0 → 7F2 transition of Eu3+. The optimal dopant concentration (x) of the as-prepared phosphor was x = 0.60 mol and the concentration quenching mechanism was evaluated as the electric quadrupole–quadrupole interaction. The BaBiNaTeO6:Eu3+ exhibited good thermal stability and the corresponding activation energy (Ea) was obtained to be 0.27 eV. The chromaticity points of phosphors were near the edge of the red region of the Commission Internationale De L’Eclairage (CIE) 1931 chromaticity diagram. As-prepared white LED based on the GaN blue chip exhibited relatively low correlated color temperature (CCT) of 5042.5 K and high color rendering index (CRI) of 91.6. All characterizations suggest that these double perovskite BaBiNaTeO6:Eu3+ red-emitting phosphors have promising applications in illumination and display field based on blue LEDs. [ABSTRACT FROM AUTHOR]

Due to the mirror image symmetry of laser mirror welding heat sources, the post-weld deformation is observably lower than that of conventional welding methods. However, the mechanism of gravitational effects on the coupled keyhole molten pool at different welding positions is still unclear, which results in the tough control of welding defects, hindering the application of laser mirror welding in precision manufacturing of aerospace structural parts. In this study, the gravity effects on keyhole behaviors in laser mirror welding of 2219 aluminum alloy were investigated by establishing a computational fluid dynamics (CFD) model. The keyhole morphology, coupling characteristics, and its dynamic evolution as well as force conditions were analyzed at length by employing the calibrated model. The results showed that gravity prominently affects the fluid velocity in the molten pool, which determines the keyhole characteristics. The keyhole surface flow, which enlarges the keyhole diameter, is impeded by gravity, resulting in weak keyhole coupling. The keyhole area on the weld cross-section before coupling is less than 2 mm2 and is negatively correlated with the gravitational component on this section. The keyhole area after coupling is tightly relevant to the keyhole diameter. The increase or decrease in the keyhole diameter is contingent on the resultant direction of gravity, fluid pressure, and vapor recoil pressure. Additionally, the keyhole coupling and dynamic behaviors in the welding direction are primarily affected by the surface tension gradient, while slightly affected by gravity. [ABSTRACT FROM AUTHOR]

Laser melting deposition (LMD) is an advanced repairing and remanufacturing technology that involves complex thermodynamic and kinetic characteristics in a molten pool. A thorough understanding of the thermal-fluid dynamic behavior of molten metal is crucial for investigating the distribution of reinforced particles and the characterization of solidification. This study proposes a three-dimensional transient thermal-fluid coupling model for describing thermal-fluid dynamic behavior and particle migration behavior within a molten pool during LMD. The simulated morphology of the deposition layer and temperature agree well with the experiments. The simulation results indicate that Marangoni convection induced by temperature gradient dominates the convection mode. The fluid velocity distribution along the scanning direction of the molten metal is showing M shape. Meanwhile, the dimension of molten pool increases slightly, and the Marangoni convection becomes more vigorous with higher heat input. The Marangoni motion tends to drive the TiC particle migration from the center to both lateral sides, resulting in a more uniformly distributed of TiC particle in deposition layer. Furthermore, the solidification parameters at solid–liquid interface are calculated, which used to assess the solidification microstructure in deposition layer. [ABSTRACT FROM AUTHOR]

In the Majiagou landslide of the Three Gorges Reservoir Area, there appears a wide crack between the anti-pile and sliding body behind the piles, which can hardly be clarified by the sliding force of the sliding body. Therefore, the deformation mechanism of anti-piles in the Majiagou landslide was studied to explain how the crack appears between the anti-pile and sliding body behind the piles from perspectives of embedded rock degradation and declining water level. The mechanical degradation of the embedded rock was studied experimentally with triaxial compression and Brazilian splitting tests at first. Then, the embedded rock degradation and declining water level were introduced into the FLAC3D model, where the deformation mechanism of anti-piles and soils behind the anti-piles were studied. The results show that the rock resistances in front of anti-piles gradually decrease and the embedding effect of anti-piles gradually weakens due to the embedded rock degradation, resulting in plastic deformation in the rock and forward inclination of anti-piles. In addition, the declining water level leads to an increasing seepage force, leading to an increasing sliding deformation of the sliding body in front of the anti-piles, which weakens the front support of the anti-pile. Thus, the anti-pile displacements continually increase and exceed those of the sliding body behind the pile, and a wide crack appears between the anti-pile and sliding body behind the piles as a result. Consequently, the mechanical and deformation parameters after degradation should be employed for the reinforcement design of anti-piles in reservoir bank slopes. [ABSTRACT FROM AUTHOR]

Wire arc additive manufacturing (WAAM) is widely studied due to its high deposition rate. However, WAAM samples have poor forming quality compared with other additive manufacturing technologies. The quality of sample formation is directly related to the time required for subsequent mechanical processing. Hence, cycle time can further be reduced by controlling the forming quality. Additionally, better forming quality results in less material wastage. Therefore, the forming quality of samples has always been the focus of WAAM. In this paper, the droplet transfer process of the WAAM is shot with a high-speed camera. This article attempts to explain the WAAM forming process from the perspective of droplet transfer and evaluate the influence mechanism of droplet transfer on the side surface forming quality. High-speed photography is used to extract the molten pool size and droplet transfer frequency. The study also explored the variation of these factors with wire feed speed and number of layers. A two-dimensional droplet transfer model is established based on the results of high-speed photography to study the droplet transfer process. Next, the 3D sample model is built to obtain the roughness of deposition samples. Finally, the relationship between the forming quality and droplet transfer process is studied through the fitting planes. The relationship model of wire feeding speed, molten pool length/droplet transfer frequency, and roughness is obtained. The roughness of the side surface increases with higher wire feed speeds when the wire feed speed is 5.5–6.5 m/min. However, at a wire feed speed of 7.0 m/min, the roughness of the side surface suddenly decreases. The droplet transfer motion rule is then used to explain this change in forming quality. [ABSTRACT FROM AUTHOR]

Friction stir additive manufacturing technology has emerged as an efficient solid-state process option that provides superior connectivity for lightweight structural material with equiaxed microstructures and outstanding mechanical properties. In this paper, a multilayer ring-shaped build made from 6061-T6 aluminum alloy using friction stir additive manufacturing (FSAM) was characterized. The rotating torque exerted on the friction tool by the surrounding material was measured as it moves to the middle and the end of the ring. Additionally, the correlation between the microstructure and the rotating torque was investigated. The results revealed a significant decrease in rotating torque when the stir tool returned to its original position in the additive zone, leading to a reduction in grain size within the additive zone. Underneath the bottom of the stir zone, there was an overlapping interface filled with deformed grains. Along the horizontal direction, the highest hardness existed in the base material region, while the lowest value appeared in the mixed area of the thermal–mechanical affected zone and heat-affected zone. The hardness value of the stir zone was found to be intermediate between the base material region and the mixed area of the thermal–mechanical affected zone and heat-affected zone. The highest and lowest hardness values along the tool-axial direction were observed at the top of the stir zone and the overlapping interface below it. [ABSTRACT FROM AUTHOR]

The stable recovery of gas sensors is an important indicator for evaluating their performance. Hitherto, the use of external light sources and/or an increase in the operating temperature has been effective in improving the recovery rate of gas sensors. Herein, heterojunctions were formed between the two-dimensional transition metal dichalcogenide nanosheets and zero-dimensional ZnO nanoparticles to improve the recovery rate of a NO2 sensor. Scanning electron microscopy and Raman spectroscopy suggested a successful deposition of ZnO nanoparticles onto the MoS2 and WSe2 nanosheets. The sensing response to 10 ppm NO2 gas at 100 °C indicated that the heterojunction formed by ZnO and MoS2 or WSe2 successfully improved the recovery rate of the sensor by 11.87% and 19.44%, respectively, whereas the sensitivity remained constant. The proposed approach contributes to improving the performance of gas sensors. [ABSTRACT FROM AUTHOR]

Laser welding is a feasible process for joining the additive manufactured (AMed) parts to meet the manufacturing demand of specific large-scale components. Microstructure and property evolution as well as weldability of the laser welding of wire arc additive manufactured (WAAMed) Al-Cu alloy are investigated. Results indicate that the WAAMed Al-Cu alloy has excellent laser weldability and the joint is nearly free of defect. The width of the heat-affected-zone (HAZ) and equiaxed crystal zone (EQZ) as well as the grain size of the fusion zone (FZ) will increase with higher laser power and heat input. The joint with laser power of 3500 W has the highest tensile strength and elongation, reaching 203.48 MPa and 4.13%. The result from electron backscatter diffraction (EBSD) test indicates that the texture intensity will affect tensile properties. The tensile strength and elongation of the laser welded WAAM sample perpendicular to the deposition direction are higher than that parallel to the deposition direction. The microhardness value of HAZ is higher than that of FZ and BM due to 163 HV. The feasibility of laser welding of WAAMed samples is validated, and process parameters are found for hybrid manufacturing of large-scale components. [ABSTRACT FROM AUTHOR]

Core-shell bimetallic nanocatalysts have attracted long-standing attention in heterogeneous catalysis. Tailoring both the core size and shell thickness to the dedicated geometrical and electronic properties for high catalytic reactivity is important but challenging. Here, taking Au@Pd core-shell catalysts as an example, we disclose by theory that a large size of Au core with a two monolayer of Pd shell is vital to eliminate undesired lattice contractions and ligand destabilizations for optimum benzyl alcohol adsorption. A set of Au@Pd/SiO2 catalysts with various core sizes and shell thicknesses are precisely fabricated. In the benzyl alcohol oxidation reaction, we find that the activity increases monotonically with the core size but varies nonmontonically with the shell thickness, where a record-high activity is achieved on a Au@Pd catalyst with a large core size of 6.8 nm and a shell thickness of ~2–3 monolayers. These findings highlight the conjugated dual particle size effect in bimetallic catalysis. Tailoring both the core size and shell thickness of core-shell bimetallic nanocatalysts to the dedicated geometrical and electronic properties are vital for catalytic performance optimization. Here the authors demonstrate such conjugated dual particle size effects on Au@Pd catalyzed benzyl alcohol oxidation. [ABSTRACT FROM AUTHOR]

The bottom-locking joint is widely used in the aerospace manufacturing field as an imperative connection structure. The laser welding experiment for the Ti-6Al-4V titanium alloy bottom-locking joint is carried out in the present paper. Meanwhile, porosity in the weld seam including the process porosity and metallurgical porosity is investigated. Furthermore, it is novel that the distribution, element characteristics, and formation mechanism of process porosities and metallurgical porosities in the bottom-locking joint are comprehensively analysed based on the porosity morphology, microstructure, and element analysis of the resultant bottom-locking joints. The process porosity, which mainly appeared in the weld seam centre, is formed by the combined effect of two mechanisms which closely related to the dynamic behaviour of the molten pool and the stability of the keyhole. Besides, a large number of micropores with a diameter of 2–5 µm are observed on the surface of the process porosity, whose formation is related to the evaporation of elements. Moreover, the tensile stress generated during the solidification and shrinkage of the molten metal is the main factor leading to microcracks in the micropores. The nucleation characteristics of bubbles cause metallurgical porosities to be mainly distributed at the bottom of the weld seam. [ABSTRACT FROM AUTHOR]

Due to the small range of plastic deformation temperatures during hot rolling of Zircaloy-4 plates, it is important to determine the appropriate flow behaviors for plate profile control of Zircaloy-4 plates. The developed microstructures and mechanical properties of Zircaloy-4 are evaluated by metallographic observations and Gleeble-3800 thermal simulation tester. To meet the need of data with small-sample properties, the support vector regression (SVR) algorithm is adopted to predict the constitutive model of Zircaloy-4, and the improved particle swarm optimization algorithm (IPSO) is used to optimize parameters of SVR algorithm. Meanwhile, results indicate that the correlation coefficient (R2) value of zirconium alloy constitutive model is 96.805%. Based on employed algorithm, comparing with modified Arrhenius model, the results show the superiority of IPSO-SVR algorithm. This provides an important theoretical basis for FE simulation of controlling the Zircaloy-4 plate shape during hot rolling process. [ABSTRACT FROM AUTHOR]

The development of high-performance strain sensors has attracted significant attention in the field of smart wearable devices. However, stretchable strain sensors usually suffer from a trade-off between sensitivity and sensing range. In this study, we investigate a highly sensitive and stretchable piezoresistive strain sensor composed of a hybrid film of 1D multi-walled carbon nanotube (MWCNT) and 2D graphene that forms a percolation network on Ecoflex substrate by spray coating. The mass of spray-coated MWCNT and graphene and their mass ratio are modulated to overcome the trade-off between strain sensitivity and sensing range. We experimentally found that a stable percolation network is formed by 0.18 mg of MWCNTs (coating area of 200 mm2), with a maximum gauge factor (GF) of 1,935.6 and stretchability of 814.2%. By incorporating the 0.36 mg of graphene into the MWCNT film (i.e., a mass ratio of 1:2 between MWCNT and graphene), the GF is further improved to 12,144.7 in a strain range of 650–700%. This high GF is caused by the easy separation of the graphene network under the applied strain due to its two-dimensional (2D) shape. High stretchability originates from the high aspect ratio of MWCNTs that bridges the randomly distributed graphenes, maintaining a conductive network even under sizeable tensile strain. Furthermore, a small difference in work function between MWCNT and graphene and their stable percolation network enables sensitive UV light detection even under a significant strain of 300% that cannot be achieved by sensors composed of MWCNT- or graphene-only. The hybrids of MWCNT and graphene provide an opportunity to achieve high-performance stretchable devices. [ABSTRACT FROM AUTHOR]

In order to meet the shape control requirements of "dead flat" transverse thickness profile of electrical steel sheet in cold rolling process, the 3D finite element model (FEM) for roll stacks and strip of 6-high tandem cold rolling mills (TCMs) was built with the developed Edge Drop Control Work Rolls for Non-shifting (EDW-N). The efficiency curves of the work roll bending (WRB), the intermediate roll bending (IRB), and the intermediate roll shifting (IRS) in cold rolling process are obtained for transverse thickness profile control performance. The control strategy of multi-stand and multi-variable profile and flatness control actuators, i.e., WRB, IRB, and IRS of stands 1 ~ 5 in 6-high TCMs is proposed based on the GA-PSO hybrid algorithm with better optimization ability. The results show that the control strategy can fully exploit the shape control ability and achieve the high precision control for transverse thickness profile of 6-high TCMs. The industrial application on the production gives remarkable results that the rate of the measured strip crown less than 7 μm increased from 38.58 to 67.74% for electrical steel sheet in the 1420-mm 6-high TCMs. The control strategy has applied to the production successfully. [ABSTRACT FROM AUTHOR]

Laser direct joining of carbon fiber-reinforced thermoplastic composites (CFRTP) to aluminum alloy with diverse surface micro-patterns was performed. The influence of micro-pattern type on interface characteristic and mechanical property of CFRTP/aluminum alloy laser bonding joint was concerned especially. Prior to the laser joining, two different micro-patterns including groove structure and circular hole structure were fabricated on the metal surface using nanosecond pulsed laser. Then, the appearance of joint and the morphology at joining interface were observed by optical microscope and scanning electron microscope. Moreover, the tensile shear test was conducted to obtain the fracture load and fracture surface morphology. The results indicated that the cross section of the groove structure was a trapezoid, while that of the circular hole structure was a triangle with a large ratio of depth to diameter. In spite of the more pores existed at the interface of joints with circular hole structure, this type of micro-pattern strengthened the mechanical anchoring effect between CFRTP and aluminum alloy more significantly. With the change of micro-pattern from groove structure to circular hole structure, the maximum tensile load of laser bonding joint increased from 1616.40 to 2623.40 N, and the main failure mode transformed from interface failure to cohesive failure. The micro-pattern fabricated on the metal surface before the laser joining process is an effective approach to obtain the larger bonding area and higher mechanical strength of laser bonding joint. [ABSTRACT FROM AUTHOR]

As the material experiences non-uniform thermal expansion and contraction under different thermal behavior during laser melting deposition (LMD), the microstructure of the components will be affected, which also causes changes in mechanical properties. It is essential to understand the thermal behavior of the melt pool during LMD to improve the microstructure and joint quality. In this study, two 80-mm-thick Ti6Al4V plates are successfully joined using three different scanning speeds (10, 15, and 20 mm/s). The effects of thermal behavior on the grain morphology and dimension of deposition area, equiaxed crystal zone (EQZ), and the substrate at different scanning speeds are quantitatively analyzed. The results show that the fine equiaxed crystals are formed near the joint boundary due to the high-temperature gradient and cooling rate. The growth direction of fine columnar crystals continuously changes from the joint boundary to the center of the deposition area due to the change of heat-extraction direction. However, the epitaxial growth direction of the coarse columnar crystal is the same as the previous deposition layer at the center of the deposition area. Given the effect of high heat accumulation and low-temperature gradient during LMD, the dimension of columnar crystal is coarsen significantly at the center of the deposition area. [ABSTRACT FROM AUTHOR]

In this investigation, a sinusoid modulated pulse gas metal arc welding (SP-GMAW) method based on a current waveform control method and on the welding mechanism of pulsed gas metal arc welding (P-GMAW) was proposed. This method achieved smooth control over the welding current. The process formulas were simplified. Then, the control parameters were discussed and optimized. Finally, three comparison experiments were conducted. The results indicated that the SP-GMAW method, as an improved double-pulsed gas metal arc welding (DP-GMAW) method, had the following features: The SP-GMAW minimized porosity rate and generated palpable weld ripples in contrast with the P-GMAW. The SP-GMAW produced the finest fusion zone grain, highest fusion zone microhardness, and highest tensile strength among three welding methods. The feasibility and superiority of the method for welding aluminum sheet were verified. [ABSTRACT FROM AUTHOR]

Shallow trophoblast invasion is a common pathological feature of preeclampsia. The 67 kDa laminin receptor 1 (LR1) is a laminin-binding protein that has been reported to be down-regulated in preeclamptic placentas. The aim of the present study was to determine the functional role of LR1 in the migration and invasion of the trophoblast cell line, JEG3 cells. RNA interference mediated by plasmid expressing LR1 short hairpin RNA (shRNA) was utilized to knockdown LR1 expression in JEG3 cells. We found that the mRNA and protein expression levels of LR1 were significantly reduced in LR1-specific shRNA transfected cells compared with the untransfected and control shRNA transfected cells. The wound healing and Transwell invasion assays demonstrated that LR1 knockdown remarkably suppressed the migration and invasion potential of JEG3 cells. The gelatin zymography assay showed that LR1 knockdown greatly reduced matrix metalloproteinase (MMP)-2 and MMP-9 activities in the culture supernatants. Western blot analysis showed that LR1 shRNA significantly decreased expression levels of MMP-2, MMP-9 and phospho-extracellular signal-regulated kinase, but increased expression levels of tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 in comparison to the control vector-transfected cells. In conclusion, our data support an important role for LR1 in regulating trophoblast invasion and migration, and suggest a possible pathological mechanism of preeclampsia. [ABSTRACT FROM AUTHOR]

Drug delivery systems based on polymer microspheres have received considerable attention. Ceftiofur sodium and ceftiofur hydrochloride is widely used for the treatment of bacterial diseases in animals but the delivery in vivo has not been reported. In this paper, we report the synthesis of microspheres from gelatin and PLGA, two kinds of typical natural and artificial materials, for loading ceftiofur and the in vivo investigation of the pharmacokinetics in beagle dogs. By controlling the synthesis parameters, gelatin and PLGA microspheres with diameter between 5 and 35 microns were obtained. Assay procedures based on high performance liquid chromatography were evaluated and confirmed. The dogs were randomly divided into three groups, i.e., control group, gelatin group, and PLGA group and administrated via intravenous injection. Plasma concentrations of ceftiofur over time were measured and analyzed. Results indicate that the main kinetic parameters do not show significant difference for the gelatin group and control group, but the area under the curve, plasma half-life, apparent volume of distribution, and clearance ratio of PLGA group show significant difference from the gelatin group and the control group. The PLGA microspheres show a low area under the curve but long time release. [ABSTRACT FROM AUTHOR]

Macrophage scavenger receptor 1 (MSR1) mediates the endocytosis of modified low-density lipoproteins and plays an important antiviral role. However, the molecular mechanism underlying MSR1 antiviral actions remains elusive. We report that MSR1 activates autophagy to restrict infection of Chikungunya virus (CHIKV), an arthritogenic alphavirus that causes acute and chronic crippling arthralgia. Msr1 expression was rapidly upregulated after CHIKV infection in mice. Msr1 knockout mice had elevated viral loads and increased susceptibility to CHIKV arthritis along with a normal type I IFN response. Induction of LC3 lipidation by CHIKV, a marker of autophagy, was reduced in Msr1−/− cells. Mechanistically, MSR1 interacted with ATG12 through its cytoplasmic tail and this interaction was enhanced by CHIKV nsP1 protein. MSR1 repressed CHIKV replication through ATG5-ATG12-ATG16L1 and this was dependent on the FIP200-and-WIPI2-binding domain, but not the WD40 domain of ATG16L1. Our results elucidate an antiviral role for MSR1 involving the autophagic function of ATG5-ATG12-ATG16L1. Using Msr1 knockout mice, Long Yang et al. demonstrate that macrophage scavenger receptor 1 (MSR1) activates autophagy to restrict the proliferation of Chikungunya virus, an alphavirus that causes crippling joint stiffness. This study provides insights into how host cellular machinery fights off Chikungunya virus. [ABSTRACT FROM AUTHOR]

In this study we quantified the alterations of retinal histone post-translational modifications (PTMs) in diabetic rats using a liquid chromatography - tandem mass spectrometry (LC-MS/MS) approach. Some diabetic rats were subsequently treated with minocycline, a tetracycline antibiotic, which has been shown to inhibit the diabetes-induced chronic inflammation in the retinas of rodents. We quantified 266 differentially modified histone peptides, including 48 out of 83 methylation marks with significantly different abundancein retinas of diabetic rats as compared to non-diabetic controls. About 67% of these marks had their relative abundance restored to non-diabetic levels after minocycline treatment. Mono- and di-methylation states of histone H4 lysine 20 (H4K20me1/me2), markers related to DNA damage response, were found to be up-regulated in the retinas of diabetic rats and restored to control levels upon minocycline treatment. DNA damage response biomarkers showed the same pattern once quantified by western blotting. Collectively, this study indicates that alteration of some histone methylation levels is associated with the development of diabetic retinopathy in rodents, and the beneficial effect of minocycline on the retinas of diabetic rodents is partially through its ability to normalize the altered histone methylation levels. [ABSTRACT FROM AUTHOR]

A C-type lectin (CfLec-3) from Chlamys farreri with three carbohydrate-recognition domains (CRDs) was selected to dissect the possible mechanisms of PAMP binding and functional differentiation of invertebrate lectins. CfLec-3 distributed broadly, and its mRNA expression in hemocytes increased significantly after stimulations with LPS, PGN or β-glucan, but not poly(I:C). The recombinant CfLec-3 (rCfLec-3) could bind PAMPs and several microbes. rCfLec-3 mediated hemocytes phagocytosis against Escherichia coli and encapsulation towards agarose beads. Obvious functional differentiation occurred among the three CRDs, as CRD1 exhibited higher activity to bind PAMPs, while CRD2/3 were expert in promoting hemocyte mediated opsonisation. The tertiary structural differences were suspected to be associated with such functional differentiation. PAMP binding abilities of CfLec-3 were determined by Ca2+-binding site 2 motif. When Pro in this motif of each CRD was mutated into Ser, their PAMP binding abilities were deprived absolutely. rCRD2 acquired mannan binding capability when its EPD was replaced by EPN, but lost when EPN in rCRD3 was changed into EPD. The Pro in Ca2+-binding site 2 was indispensable for PAMPs binding, while Asn was determinant for specific binding to mannan. It shed new insight into PAMPs binding mechanism of invertebrate C-type lectins and their functional differentiation. [ABSTRACT FROM AUTHOR]

Considering the unique soil structure and the temperature rise effect of seawater’s electrical and thermal parameters, accurately simulating the grounding characteristics of marine DC grounding electrodes is the basis for ensuring the safe and stable operation of offshore wind power grid-connected DC projects. The paper proposes a dynamic finite element model of ocean grounding electrode characteristics based on the coupling of circuits and electrical–thermal fields. In the finite element model, soil parameters can be controlled by the time-varying temperature distribution, and the dynamic process of the coupling of soil electrical and thermal fields in the process of direct flow can be accurately simulated. A time-varying equivalent circuit model for controlling the electric–thermal field can be implemented to accurately simulate the dynamic process of the shunt coefficient for each conductor segment in a composite DC grounding electrode with multiple injection points. The effectiveness is verified by comparing with the experimental data. Finally, the dynamic flow process, temperature rise process and their mutual influence are quantitatively analyzed. [ABSTRACT FROM AUTHOR]