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To study the shape characteristics of the coal and rock under the horizontal stress, thoroughly understand the mechanism of coal and gas outburst, the analysis and comparison of cave shape characteristics and numerical simulation results in the outburst site of Pingdingshan No.8 coal mine are made to prove the accuracy and feasibility of the numerical simulation method, furthermore, the development characteristics of the shape of the caves can be obtained under the conditions of different conditions of horizontal stress σH. The experimental results show that trend length and inclination length of the outburst caves increase exponentially with the increase of horizontal stress σH, and the trend length increases faster, when the horizontal stress σH reaches 28 MPa, the growth rate of the curve is obviously improved; the hole length increases linearly with the increase of the horizontal stress σH, and the growth rate is slow.

Background: Severe myocarditis is often accompanied by cardiac fibrosis, but the underlying mechanism has not been fully elucidated. CXCL4 is a chemokine that has been reported to have pro‐inflammatory and profibrotic functions. The exact role of CXCL4 in cardiac fibrosis remains unclear. Methods: Viral myocarditis (VMC) models were induced by intraperitoneal injection of Coxsackie B Type 3 (CVB3). In vivo, CVB3 (100 TCID50) and CVB3‐AMG487 (CVB3: 100 TCID50; AMG487: 5 mg/kg) combination were administered in the VMC and VMC+AMG487 groups, respectively. Hematoxylin and eosin staining, severity score, Masson staining, and immunofluorescence staining were performed to measure myocardial morphology in VMC. Enzyme‐linked immunosorbent assay (ELISA) and quantitative reverse transcription polymerase chain reaction (qRT‐PCR) were performed to quantify inflammatory factors (IL‐1β, IL‐6, TNF‐α, and CXCL4). Aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and creatine kinase‐myocardial band (CK‐MB) levels were analyzed by commercial kits. CXCL4, CXCR3B, α‐SMA, TGF‐β1, Collagen I, and Collagen III were determined by Western blot and immunofluorescence staining. Results: In vivo, CVB3‐AMG487 reduced cardiac injury, α‐SMA, Collagen I and Collagen III levels, and collagen deposition in VMC+AMG487 group. Additionally, compared with VMC group, VMC+AMG group decreased the levels of inflammatory factors (IL‐1β, IL‐6, and TNF‐α). In vitro, CXCL4/CXCR3B axis activation TGF‐β1/Smad2/3 pathway promote mice cardiac fibroblasts differentiation. Conclusion: CXCL4 acts as a profibrotic factor in TGF‐β1/Smad2/3 pathway‐induced cardiac fibroblast activation and ECM synthesis, and eventually progresses to cardiac fibrosis. Therefore, our findings revealed the role of CXCL4 in VMC and unveiled its underlying mechanism. CXCL4 appears to be a potential target for the treatment of VMC. [ABSTRACT FROM AUTHOR]

Tannic acid (TA) is a plant polyphenol capable of coating hydrothermally grown LiFePO4 nanocrystals by simple wet impregnation and drying. Mild pyrolysis in an inert atmosphere transforms the TA coating on LiFePO4 nanocrystals into homogeneous and compact carbon films. Introducing conductive carbon films on LiFePO4 nanocrystals increases the electrical conductivity of the LiFePO4/C composite. However, reaction kinetics revealed that excessively thick carbon films limit the Li+ diffusivity of the LiFePO4/C composite during delithiation/lithiation. Therefore, the electrical conductivity and Li+ diffusivity must be balanced to achieve the required electrochemical properties. [ABSTRACT FROM AUTHOR]

Ever increasing demands for portable electronics and electric vehicles critically require high-rate Li-ion batteries (LIBs) whose performance fundamentally depends on electrode materials. However, currently commercialized anode materials including graphite and silicon fail to fulfill the higher requirement because of their intrinsically inferior rate capability. Here, we report submicron Ti2CTx (s-Ti2CTx) MXene particulates as a high-rate intercalation anode material for LIBs. The particulates are derived from the layered ternary Ti2AlC MAX phase that is readily fabricated by the molten salt method. The synthesized s-Ti2CTx particulates have a high specific capacity of ∼155 mA h g−1 even at a high current density of 10 A g−1, exhibiting high rate capability. Specifically, the particulates, with a nominal chemical formula of Ti2CTxLi1.4, can release ∼57% of their revisable capacity (∼270 mA h g−1) in 56 s and they exhibit good capacity retention during 1000 cycles. As evidenced by comprehensive electrochemical characterization studies, a reduction in the lateral size of MXene particulates remarkably facilitates an interlayer (de)lithiation process compared with their large counterparts. The s-Ti2CTx also offers an opportunity to fabricate flexible electrodes with outstanding rate performance and cyclability. Our results provide a platform for studying MXene-based intercalation anode materials with desired electrochemical performance for high-rate LIBs. [ABSTRACT FROM AUTHOR]

MXenes represent an emerging family of two-dimensional materials of transition metal carbides/carbonitrides terminated with functional groups like –O, –OH, and –F on the chemically active surface of MX slabs. As a member of the family, Nb2CTx exhibits superior lithium storage capacity over most of the other MXenes as anode materials in lithium-ion batteries (LIBs). However, an in-depth understanding of the charge storage mechanism is still lacking so far. Here, through combining complementary experiments and density functional theory calculations, we provide insights into the (de)lithiation process. Specifically, Nb2CTx with dominant –O functional groups stores charge as a result of changes in the oxidation states of both transition metals Nb and O, which is supported by Bader charge analysis showing a significant change in the oxidation states of Nb and O upon lithiation. As monitored by ex situ X-ray diffraction, the interlayer spacing of Nb2CTx changes slightly upon lithium ion (de)intercalation, corresponding to a volume change of only 2.3% with a near zero-strain feature. By coupling with a LiFePO4/C cathode, the full cell presents superior rate capability and cycling stability as well. The insights into the charge storage mechanism of Nb2CTx in this work provide useful guidance for the rational design of MXene-based anode materials for high-performance LIBs. [ABSTRACT FROM AUTHOR]