Study on instability mechanism of soft rock roadway and pressure-relief bolt-grouting support technology.

Aiming at the engineering problem of roadway deformation and instability of swelling soft rock widely existed in Kailuan mining area, the mineral composition and microstructure of such soft rock were obtained by conducting scanning electron microscopy, X-ray diffraction experiments, uniaxial and conventional triaxial tests, and the law of softening and expanding of such soft rock and the failure mechanism of surrounding rock were identified. The combined support scheme of multi-level anchor bolt, bottom corner pressure relief and fractional grouting is proposed. The roadway supporting parameters are adjusted and optimized by FLAC3D numerical simulation, and three supporting methods of multi-layer anchor bolt, bottom corner pressure relief and fractional grouting are determined and their parameters are optimized. The study results show that: the total amount of clay minerals is 53-75%, pores, fissures, nanoscale and micron layer gaps are developed, providing a penetrating channel for water infiltration to soften the surrounding rock; the three-level anchor pressure-relief and grouting support technology can control the sinking amount of the roof within 170 mm, the bottom drum amount within 210 mm, the bolts of each level is evenly distributed in tension, and the maximum stress and bottom drum displacement in the pressure relief area are significantly reduced; the pressure-relief groove promotes the development of bottom corner cracks, accelerates the secondary distribution of peripheral stress, and weakens the effect of high stress on the shallow area. Using time or displacement as the index, optimizing the grouting time, filling the primary and excavation cracks, blocking the expansion and softening effect of water on the rock mass, realizing the dynamic unity of structural yielding pressure and surrounding rock modification, has guiding significance for the support control of soft rock roadway.

An innovative parameter optimization of Spark Streaming based on D3QN with Gaussian process regression.

Nowadays, Spark Streaming, a computing framework based on Spark, is widely used to process streaming data such as social media data, IoT sensor data or web logs. Due to the extensive utilization of streaming media data analysis, performance optimization for Spark Streaming has gradually developed into a popular research topic. Several methods for enhancing Spark Streaming's performance include task scheduling, resource allocation and data skew optimization, which primarily focus on how to manually tune the parameter configuration. However, it is indeed very challenging and inefficient to adjust more than 200 parameters by means of continuous debugging. In this paper, we propose an improved dueling double deep Q-network (DQN) technique for parameter tuning, which can significantly improve the performance of Spark Streaming. This approach fuses reinforcement learning and Gaussian process regression to cut down on the number of iterations and speed convergence dramatically. The experimental results demonstrate that the performance of the dueling double DQN method with Gaussian process regression can be enhanced by up to 30.24%.

Evaluation of Effective Crosslinking Density for Pseudo-Semi Interpenetrating Polymer Networks Based on Polyether Glycols Mixture by Dynamic Mechanical Analysis.

Pseudo-semi interpenetrating polymer networks (pseudo-semi IPNs) are a special example of topological isomerism in macromolecules, which have attracted significant attention in recent years with a high potential in a variety of engineering applications of polymeric materials. In this article, pseudo-semi IPNs were synthetized by sequential polymerization of thermoplastic polymers (TPEs) in the presence of thermosetting elastomer (TSEs) with contents of 10, 20, 30, 40 and 50 wt.% in a vacuum oven at 60 °C for about 72 h. In addition, this article describes a method for researching the elastic modulus, effective crosslinking density and physical crosslinking density of TSEs and pseudo-semi IPNs. The inherent interactions and entanglements of pseudo-semi IPNs were discussed by analyzing the changes in elastic modulus and effective crosslinking density at different temperatures. The results show that after the TPE was added to the TSE matrix as a plastic-reinforced material, the ductility increased from 89.6% to 491%, the effective crosslinking density was increased by 100% at high temperatures and the strength of the material matrix was significantly improved. Two physical events take place in our pseudo-semi IPNs as result of energy dissipation and polymeric chains mobility.

Preparation and inhibitory effect of salicin dimethyl ether in Laryngeal cancer cells through the apoptosis activation.

Laryngeal cancer is detected commonly worldwide, and it ranks second highest in incidence among the respiratory tract neoplasms following only head and neck squamous cell cancer. In the present study salicin dimethyl ether was synthesized and evaluated against laryngeal cancers cells for anticancer property. MTT assay was used for the measurement of changes in TU686 and Tu212 cell proliferation while as induced apoptosis was detected by flow cytometry. Protein expression was determined by western blotting and expression of mRNA by RT-PCR assay. In the present study salicin dimethyl ether was synthesized by the reaction of salicin with methyl iodide using sodium hydride as base. Salicin dimethyl ether treatment led to a significant decrease in TU686 and Tu212 cell proliferation in a dose-dependent manner. In TU686 and Tu212 cells salicin dimethyl ether treatment caused a significant increase in cell apoptosis and elevated caspase-3 activity. Treatment with salicin dimethyl ether led to a prominent reduction in Bcl-2 protein expression in TU686 and Tu212 cells at 72 h. Salicin dimethyl ether treatment led to a prominent decrease in p-PI3K and p-Akt protein expression in TU686 and Tu212 cells, compared to the untreated cells. A significant increase in miR­15a expression in TU686 and Tu212 cells was observed on treatment with salicin dimethyl ether at 72 h. In summary, the current study demonstrates that salicin dimethyl ether, a synthetic derivative of salicin, suppresses proliferation of TU686 and Tu212 cells. The underlying mechanism involves induction of apoptosis, inhibition of PI3K/Akt pathway and promotion of miR-15a expression. Therefore, salicin dimethyl ether may be used for inhibition of laryngeal cancer growth, however, in vivo studies need to be conducted to confirm the effect.

Effect of Mo Content on In-Situ Anisometric Grains Growth and Mechanical Properties of Mo2FeB2-Based Cermets.

Mo2FeB2-based cermets have wide applications in fields of wear resistance, corrosion resistance and heat resistance due to their simple preparation process, low-cost raw materials, and prominent mechanical properties. Herein, Mo2FeB2-based cermets with xMo (x = 43.5, 45.5, 47.5, 49.5, wt.%) were prepared by means of the vacuum liquid phase sintering technique. Investigations on the microstructure and mechanical properties of Mo2FeB2-based cermets with Mo addition were performed. Experimental results show that, with Mo content increasing, the average particle size decreases gradually, revealing that the grain coarsening of Mo2FeB2-based cermets is controlled by interface reaction. In addition, Mo2FeB2 grains gradually transform from an elongated shape to a nearly equiaxed shape. The improvement of Mo2FeB2 hard phase on the morphology is mainly due to the inhibition of solution-precipitation reaction by increasing Mo. Furthermore, the relative density of cermets decreases due to the reduced Fe content. When Mo content is 47.5 wt.%, a relatively small grain size of Mo2FeB2 is obtained (about 2.03 µm). Moreover, with the increase in Mo content, hardness and transverse rupture strength (TRS) of Mo2FeB2-based cermets increase firstly and then decrease. Whereas, with increasing Mo content, the fracture toughness deteriorates gradually. When Mo content is 47.5 wt.%, the comprehensive mechanical properties of cermets are the best. The optimal raw material ratio for the preparation of Mo2FeB2-based cermets in this study is determined to be 47.5 wt.% Mo-6.0 wt.% B-Fe.

Effects of Short- and Long-Term Detraining on Maximal Oxygen Uptake in Athletes: A Systematic Review and Meta-Analysis.

V̇O2max, a gold standard for evaluating cardiorespiratory fitness, can be enhanced by training and will gradually decrease when training stops. This study, which followed the Cochrane Collaboration guidelines, is aimed at assessing the effect of short- and long-term detraining on trained individuals' V̇O2max through a systematic review and meta-analysis and performed a subgroup analysis to evaluate the effects of different ages, detraining formats, and training statuses on V̇O2max variation between short- and long-term training cessation. Web of Science, SPORTDiscus, PubMed, and Scopus, four databases, were searched, from which 21 of 3315 potential studies met the inclusion criteria. Significant decreases in V̇O2max were identified after short-term training cessation (ES = -0.62 [95% CI -0.94; -0.31], p < 0.01; within-group I 2 = 35.3%, Egger's test = -1.22, p = 0.335) and long-term training cessation (ES = -1.42 [95% CI -1.99; -0.84], p < 0.01; within-group I 2 = 76.3%, Egger's test = -3.369, p < 0.01), which shows that the detraining effect was found to be larger on V̇O2max in long-term training cessation than in short-term training cessation (Q = 6.5, p = 0.01). However, there was no significant difference regarding V̇O2max change between 30-90 days detraining and larger than 90 days detraining (Q = 0.54, p = 0.46) when conducting subgroup analysis. In addition, younger (<20) individuals showed a greater reduction in V̇O2max after long-term detraining than adult individuals (Q = 5.9, p = 0.05), and athletes with higher trained-state V̇O2max showed a significant decline in V̇O2max after long-term detraining compared with the lower trained-state group (Q = 4.24, p = 0.03). In conclusion, both short- and long-term training cessation have a detrimental effect on V̇O2max, and a greater impact on V̇O2max was found in long-term training cessation compared to short-term training cessation; however, there was no significant change in V̇O2max when the duration of training cessation was more than 30 days. To buffer the detrimental effects of detraining, especially long-term training cessation, performing some physical exercise during training cessation can effectively weaken detraining effects. Thus, to prevent athlete's V̇O2max from decreasing dramatically from detraining, athletes should continue performing some physical exercise during the cessation of training.

Eukaryotic translation initiation factor 3 subunit B promotes head and neck cancer via CEBPB translation.

BACKGROUND: Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer type worldwide. Deregulation of mRNA translation is a frequent feature of cancer. Eukaryotic translation initiation factor 3 subunit B (EIF3B) has been reported as an oncogene; however, its role in HNSCC has yet to be fully elucidated. METHODS: In this study, the clinical significance of EIF3B expression was analyzed based on TCGA datasets. Then, EIF3B expression was knocked down and its role in HNSCC was revealed. To explore the molecular mechanisms of EIF3B, we applied RNA sequencing and proteomics and acquired deregulated pathways. RNA immunoprecipitation (RIP) sequencing was conducted to reveal the target mRNAs of EIF3B, and TCGA datasets were used to validate potential targets of EIF3B. RESULTS: Elevated expression of EIF3B was observed in the HNSCC cancer samples. The expression of EIF3B was significantly correlated with the patient's sex, age, HPV infection status, T stage, N stage, perineural invasion status and survival status. EIF3B serves as a marker of an unfavorable HNSCC prognosis. EIF3B-silenced Fadu and Cal27 cells exhibited reduced cell numbers, and EIF3B knockdown induced apoptosis in both cell lines. The EIF3B-silenced cells demonstrated decreased invasion and migration capabilities, and the EIF3B knockdown group mice showed significantly decreased tumor volumes. The results show that EIF3B promotes CEBPB translation and activates the MAPK pathway and revealed that IL6R and CCNG2 are targets of EIF3B-regulated CEBPB translation. CONCLUSION: In summary, the results indicated that EIF3B is a novel oncogene in HNSCC that promotes CEBPB translation and IL6R expression, and these findings provide a link between the molecular basis and pathogenesis of HNSCC.

Comparing single or dual tracing modality on sentinel lymph node biopsy from patients who plan to omitting axillary lymph node dissection referring to the criteria of Z0011 trial: a retrospective study.

Axillary lymph node dissection (ALND) can be omitted in the part of the breast-conserving patients with positive sentinel lymph nodes (SLNs) since Z0011 trial has presented. Nevertheless, to date, no studies revealed the influence of different tracing modalities (single tracer versus dual tracers) for sentinel lymph node biopsy (SLNB) on axillary management referring to Z0011 trial criteria. This study aimed to assess whether different tracing modalities of SLNB have impact on axillary management referring to Z0011 trial criteria. The clinical data of breast-conserving patients who underwent SLNB guided by combination of methylene blue (MB) and indocyanine green(ICG) were retrospectively analyzed in our center. The numbers of metastatic (positive) SLNs guided by the single tracer and the dual tracer were compared by self-control study. 127 patients with 1-2 metastatic SLNs dyed by MB [(recorded as MB(+))]were retrieved from our database between 2016 and 2020. In these cases, 53 patients contained 86 SLNs, which were ICG staining but MB negative staining (recorded as ICG(+)/MB(-)). In addition, 16 patients contained 20 metastatic SLNs with ICG(+)/MB(-). There were six patients finally excluded patients (6/127, 4.7%) who initially met the criteria of Z0011 trial, because the further detection of ICG(+)/MB(-) SLNs led the total numbers of positive SLNs over two. The difference was statistically significant. Single tracing modality may underestimate the positive SLN numbers compared to dual tracing modality. Different tracing modalities of SLNB will significantly affect Axillary management referring to Z0011 trial criteria.

LncRNA HOXA-AS2 Promotes Oral Squamous Cell Proliferation, Migration, and Invasion via Upregulating EZH2 as an Oncogene.

Oral squamous cell carcinoma (OSCC) is one of the most common types of cancer worldwide. Accumulating evidence has shown that long noncoding RNAs (lncRNAs) serve important roles in the development of OSCC. The purpose of this study was to investigate the biological function and underlying regulatory mechanism of lncRNA homeobox A cluster antisense RNA2 (HOXA-AS2) in OSCC. RT-qPCR was performed to analyze the HOXA-AS2 expressions in human immortalized oral epithelial cell (HIOEC) line, human OSCC cell lines, and plasma. The expression of HOXA-AS2 and enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2) in Tca-8113 cells were knocked down or overexpressed by transfection with shRNA-HOXA-AS2 or pcDNA-EZH2, respectively. The interaction between HOXA-AS2 and EZH2 was validated by RNA immunoprecipitation assay. In addition, cell proliferation was assessed by CCK-8 and EdU assays. Cell cycle distribution was analyzed by flow cytometry. Cell migration and invasion were detected using wound healing and Transwell assays, respectively. Apoptosis was detected by TUNEL staining. The protein expression levels of cell cycle and apoptosis-related proteins were measured by western blot analysis. Compared with HIOEC cells, HOXA-AS2 expression in OSCC cells was upregulated. HOXA-AS2 knockdown significantly inhibited Tca-8113 cell proliferation, blocked the cell cycle by arresting cells in the G0/G1 phase, promoted apoptosis, and suppressed migration and invasion. In addition, HOXA-AS2 was predicted to directly target EZH2 and positively regulate EZH2 expression. EZH2 overexpression could reverse the inhibitory effect of HOXA-AS2 knockdown on the proliferation, migration, and invasion of Tca-8113 cells. In summary, the findings suggested that HOXA-AS2 may inhibit cell proliferation, invasion, and migration, induce cell cycle arrest in the G0/G1 phase, and increase cell apoptosis by targeting EZH2. The research indicated that HOXA-AS2/EZH2 axis may play a key role in the development of OSCC.

MiR-205 suppressed the malignant behaviors of breast cancer cells by targeting CLDN11 via modulation of the epithelial-to-mesenchymal transition.

Some Aberrant expression of miRNAs plays an important role in the occurrence and distant metastasis of breast cancer. This study aimed to identify crucial miRNA signatures for breast cancer using microarray data from the Gene Expression Omnibus database, including ductal carcinoma in situ and invasive duct carcinoma. In this study, we founded that miR-205 was significantly down-regulated in breast cancer, and the low expression of miR-205 was significantly associated with the TNM stage of breast cancer. In vitro, functional studies revealed that over-expression of miR-205 inhibited the proliferation and promoted apoptosis of breast cancer cells MDA-MB-231. Mechanistically, claudin 11 (CLDN11) was found to be the direct target of miR-205; the function of miR-205 could be exerted via downregulation of the target gene CLDN11 in breast cancer cells. Furthermore, the over-expression of miR-205 promoted the expression of the epithelial marker E-cadherin but reduced the mesenchymal markers in breast cancer cells. These results collectively indicated the tumor-suppressive role of miR-205 in breast cancer by targeting CLDN11; implying miR-205 may serve as a novel therapeutic target for breast cancer.

SnS2 Nanosheets Anchored on Nitrogen and Sulfur Co-Doped MXene Sheets for High-Performance Potassium-Ion Batteries.

Potassium-ion batteries (KIBs) are emerging as the prospective alternatives to lithium-ion batteries in energy storage systems owing to the sufficient resources and relatively low cost of K-related materials. However, serious volume expansion and low specific capacity are found in most materials systems resulting from the large intrinsic radius of K+. Herein, SnS2 nanosheets anchored on nitrogen and sulfur co-doped MXene (SnS2 NSs/MXene) are creatively designed as advanced anode materials for KIBs. SnS2 NSs/MXene with a unique hierarchical structure can not only provide fast transmission channels for K+ but also avoid the accumulation of K+ and volume expansion. These novel features make SnS2 NSs/MXene electrodes exhibit a superior reversible specific capacity of 342.4 mA h g-1 under 50 mA g-1. Also, they maintain 206.1 mA h g-1 at an even higher current density of 0.5 A g-1 over 800 cycles almost without capacity decay. Moreover, the multistep alloying reaction mechanism of SnS2 NSs/MXene composites and K+ is revealed by the ex situ X-ray diffraction measurement. In addition, the density functional theory calculations confirm the existence of Ti-S bonds between SnS2 nanosheets and MXene, which significantly enhance the structural stability and cycling electrochemical performance of SnS2 NSs/MXene composites.

Angiogenin, FGF-α, and IL-36ß have higher expression levels in aqueous humor of nAMD patients in comparison to cataract patients.

BACKGROUND: Numerous cytokines have been proven to participate in the pathogenesis of neovascular age-related macular degeneration (nAMD). The present study aimed to investigate the aqueous humor cytokine expression profile in nAMD patients before and after ranibizumab treatments in comparison to cataract patients. METHODS: This prospective study included 20 treatment-naïve nAMD eyes of 20 patients who received three consecutive monthly injections of ranibizumab. Aqueous humor samples were collected before the first (baseline), second (1 month later), and third (2 months later) injections. Controls were 20 age- and gender-matched cataract patients without any other ocular disease. The aqueous concentrations of 28 cytokines were measured using a multiplex bead assay. Central macular thickness (CMT) and maximum retinal thickness (MRT)-3 mm were measured by spectral domain optical coherence tomography (SD-OCT). The greatest linear diameter (GLD) was measured by fundus fluorescein angiography (FA). RESULTS: Three cytokines in aqueous humor, including angiogenin, interleukin-36ß (IL-36ß), and fibroblast growth factor-acidic (FGF-α) were significantly higher in nAMD patients in comparison to cataract patients, both before and after two consecutive monthly ranibizumab injections. Compared with the nAMD patients' basal levels, two consecutive monthly ranibizumab injections effectively reduced the aqueous concentrations of VEGF-A and placental growth factor (PlGF), as well as the values of CMT, MRT-3 mm, and GLD. CONCLUSIONS: Angiogenin, IL-36ß, and FGF-α have higher expression levels in nAMD patients in comparison to cataract patients, both before and after 2 months of ranibizumab therapy. These cytokines may have correlations with the pathogenesis of nAMD.

Click-Chemistry Approach toward Antibacterial and Degradable Hybrid Hydrogels Based on Octa-Betaine Ester Polyhedral Oligomeric Silsesquioxane.

An efficient process for the synthesis of degradable hydrogels containing octa-betaine ester polyhedral oligomeric silsesquioxane (POSS) through efficient thiol-ene and Menschutkin click reactions was developed. The hydrogels exhibited a yield strength of 0.36 MPa and a compressive modulus of 4.38 MPa and displayed excellent flexibility as well as torsion resistance. Antibacterial efficacy of hydrogels (and degradation products) was evaluated using Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive). Efficacy was found to increase with the concentration of cetyl chloroacetate (CCA) in the hydrogel network, reaching 93% and 99% for Escherichia coli and Staphylococcus aureus, respectively. Degradation of hydrogels was observed in weak alkali conditions (pH = 8) and at physiological conditions (pH = 7.4). The degradation time of the hydrogels could be finely tuned by variation of the CCA content in the hydrogel and environmental stimulus. The tunable degradation behavior under physiological conditions combined with high antibacterial efficacy could render the presented materials interesting for tissue engineering applications.

Porous-Carbon Aerogels with Tailored Sub-Nanopores for High Cycling Stability and Rate Capability Potassium-Ion Battery Anodes.

Developing advanced electrode materials for potassium-ion batteries (PIBs) is an emerging research area in recent years; so far, several strategies such as heteroatom doping into carbon, increasing interlayer spacing, or creating amorphous region in graphite have been investigated. Here, we studied the effect of sub-nanopores in a porous-carbon aerogel with a pore size distribution centered at around 0.8 nm and achieved outstanding PIB performance including long cycling stability (particularly at small current densities for prolonged charge/discharge period) and high rate capability with enhanced retentions. Mechanism studies reveal very high contribution from surface capacitive potassium (K)-ion storage (more than 90%) to the total capacity, and theoretical calculations show that 0.8 nm sub-nanopores lead to substantially low barrier for K-ion transport and storage, with ultrasmall diffusion energy and negligible lattice change. Sub-nanopore engineering, as demonstrated here, may be adopted to develop highly efficient and stable porous-carbon-based structures for applications in advanced energy storage systems and electrochemical catalysis.

Sintering Mechanism, Microstructure Evolution, and Mechanical Properties of Ti-Added Mo2FeB2-Based Cermets.

Four series of Mo2FeB2-based cermets with Ti contents between 0 wt.% and 1.5 wt.% in 0.5 wt.% increments were prepared by in situ reaction and liquid phase sintering technology. Influences of Ti on microstructure and mechanical properties of cermets were studied. It was found that Ti addition increases formation temperatures of liquid phases in liquid-phase stage. Ti atoms replace a fraction of Mo atoms in Mo2FeB2 and the solution of Ti atoms causes the Mo2FeB2 crystal to be equiaxed. In addition, the cermets with 1.0 wt.% Ti content exhibit the smallest particle size. The solution of Ti atoms in Mo2FeB2 promotes the transformation of Mo2FeB2 particles from elongated shape to equiaxed shape. With Ti content increasing from 0 wt.% to 1.5 wt.%, the hardness and transverse rupture strength (TRS) first increase and then decrease. The maximum hardness and TRS occur with 1.0 wt.% Ti content. However, the fracture toughness decreases as Ti content increases. The cermets with 1.0 wt.% Ti content show excellent comprehensive mechanical properties, and the hardness, fracture toughness, and TRS are HRA 89.5, 12.9 MPa∙m1/2, and 1612.6 MPa, respectively.

Integrated Analysis Reveals ENDOU as a Biomarker in Head and Neck Squamous Cell Carcinoma Progression.

BACKGROUND: Head and neck squamous cell carcinoma (HNSCC) is a leading cancer with high morbidity and mortality worldwide. The aim is to identify genes with clinical significance by integrated bioinformatics analysis and investigate their function in HNSCC. METHODS: We downloaded and analyzed two gene expression datasets of GSE6631 and GSE107591 to screen differentially expressed genes (DEGs) in HNSCC. Common DEGs were functionally analyzed by Gene ontology and KEGG pathway enrichment analysis. Protein-protein interaction (PPI) network was constructed with STRING database and Cytoscape. ENDOU was overexpressed in FaDu and Cal-27 cell lines, and cell proliferation and migration capability were evaluated with MTT, scratch and transwell assay. The prognostic performance of ENDOU and expression correlation with tumor infiltrates in HNSCC were validated with TCGA HNSCC datasets. RESULTS: Ninety-eight genes shared common differential expression in both datasets, with core functions like extracellular matrix organization significantly enriched. 15 genes showed prognostic significance, and COBL and ENDOU serve as independent survival markers in HNSCC. In-vitro ENDOU overexpression inhibited FaDu and Cal-27 cells proliferation and migration, indicating its tumor-suppressing role in HNSCC progression. GSEA analysis indicated ENDOU down-stream pathways like DNA replication, mismatch repair, cell cycle and IL-17 signaling pathway. ENDOU showed relative lower expression in HNSCC, especially HPV-positive HNSCC samples. At last, ENDOU showed negative correlation with tumor purity and tumor infiltrating macrophages, especially M2 macrophages. CONCLUSION: This study identified ENDOU as a biomarker with prognostic significance in HNSCC progression.

A C20-based 3D carbon allotrope with high thermal conductivity.

Stimulated by the high thermal conductivity of diamond together with the light mass and rich resources of carbon, a great deal of effort has been devoted to the study of the thermal conductivity of carbon-based materials. In this work, we systematically study the thermal transport properties of a three dimensional (3D) C20 fullerene-assembled carbon allotrope, HSP3-C34, in which all carbon atoms are in sp3 hybridization. The stability of HSP3-C34 is confirmed and its thermal conductivity is obtained by using first principles calculations combined with solving the linearized phonon Boltzmann transport equation. At room temperature, the thermal conductivity of HSP3-C34 is 731 W m-1 K-1, which is larger than those of many 3D carbon allotropes, such as BCO-C16 (452 W m-1 K-1), 3D graphene (150 W m-1 K-1) and T-carbon (33 W m-1 K-1). A detailed analysis of its phonons reveals that three acoustic branches are the main heat carriers at room temperature, and the optical branches gradually become important with increasing temperature. A further study on the harmonic and anharmonic properties of HSP3-C34 uncovers that the main reasons for the high thermal conductivity are the weak anharmonicity and large group velocity resulting from the strong sp3 bonding. This study provides new insights on searching for carbon allotropes with high thermal conductivity.

Two-Dimensional T-NiSe2 as a Promising Anode Material for Potassium-Ion Batteries with Low Average Voltage, High Ionic Conductivity, and Superior Carrier Mobility.

Potassium-ion batteries (KIBs) have attracted great attention due to their unique advantages including abundant resources, low redox potential of K, and feasible usage of cheap aluminum current collector in battery assembly. In the present work, through first-principles calculations, we find that the recently synthesized two-dimensional T-NiSe2 is a promising anode material of KIBs. It possesses a large capacity (247 mAh/g), small diffusion barrier (0.05 eV), and low average voltage (0.49 V), rendering T-NiSe2 a high-performance KIB anode candidate. In addition, we analyze the carrier mobility of T-NiSe2, and the results demonstrate that it possesses a superior carrier mobility of 1685 cm2/(V s), showing the potential for applications in nanoelectronic devices.

Effects of Mechanical Ball Milling Time on the Microstructure and Mechanical Properties of Mo2NiB2-Ni Cermets.

Mo2NiB2-Ni cermets have been extensively investigated due to their outstanding properties. However, studies have not systematically examined the effect of the powder milling process on the cermets. In this study, Mo, Ni, and B raw powders were subjected to mechanical ball milling from 1 h to 15 h. XRD patterns of the milled powders confirmed that a new phase was not observed at milling times of 1 h to 15 h. With the increase in the mechanical ball milling time from 1 h to 11 h, raw powders were crushed to small fragments, in addition to a more uniform distribution, and with the increase in the mechanical ball milling time to greater than 11 h, milled powders changed slightly. Mo2NiB2-Ni cermets were fabricated by reaction boronizing sintering using the milled powders at different ball milling times. The milling time significantly affected the microstructure and mechanical properties of Mo2NiB2-Ni cermets. Moreover, the Mo2NiB2 cermet powder subjected to a milling time of 11 h exhibited the finest crystal size and the maximum volume fraction of the Mo2NiB2 hard phase. Furthermore, the cermets with a milling time of 11 h exhibited a maximum hardness and bending strength of 87.6 HRA and 1367.3 MPa, respectively.

A C20 fullerene-based sheet with ultrahigh thermal conductivity.

A new two-dimensional (2D) carbon allotrope, Hexa-C20, composed of C20 fullerene is proposed. State-of-the-art first principles calculations combined with solving the linearized phonon Boltzmann transport equation confirm that the new carbon structure is not only dynamically and thermally stable, but also can withstand temperatures as high as 1500 K. Hexa-C20 possesses a quasi-direct band gap of 3.28 eV, close to that of bulk ZnO and GaN. The intrinsic lattice thermal conductivity κlat of Hexa-C20 is 1132 W m-1 K-1 at room temperature, which is much larger than those of most carbon materials such as graphyne (82.3 W m-1 K-1) and penta-graphene (533 W m-1 K-1). Further analysis of its phonons uncovers that the main contribution to κlat is from the three-phonon scattering, while the three acoustic branches are the main heat carriers, and strongly coupled with optical phonon branches via an absorption process. The ultrahigh lattice thermal conductivity and an intrinsic wide band gap make the Hexa-C20 sheet attractive for potential thermal management applications.