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The process of folding and inflating the cylindrical airbag is complicated, and there are many inconveniences in using experimental methods to study its deployment process.Two different folding methods are proposed for the cylindrical airbag and the corresponding numerical analysis models are established respectively.The nonlinear dynamics software LS-DYNA is used to study the dynamic application characteristics of the cylindrical airbag after being folded, which will affect the skin stress during the airbag deployment process.The factors of volume and internal pressure curve change are analyzed, and the influence of different folding methods and external environmental parameters on the dynamic characteristics of the cylindrical airbag is discussed.The results show that the two folding methods have their own advantages in storage space and material strength.In addition, in the environmental parameters, the external pressure has a greater impact on the stable state of the airbag after deployment, while the temperature has no obvious effect.

Two-dimensional (2D) sliding ferroelectric materials possess intriguing physical and electronic properties, thereby greatly expanding the family of 2D ferroelectrics (FEs). In this work, using first-principles calculations, we demonstrate a reversible antiferroelectricity–ferroelectricity–antiferroelectricity (AFE–FE–AFE) transition in bilayer δ-SiX (X = S/Se) along the in-plane direction during interlayer sliding. This transition primarily stems from the mechanical sliding of the top layer. Notably, spontaneous polarization (Ps) can reach up to approximately 80 pC m−1 and 70 pC m−1 for bilayers SiS and SiSe, respectively. Furthermore, the mechanism underlying this phase transition involves the interlayer between interaction energy (Einter) and strain energy (Eε). In the case of bilayer SiS, along the ABAFE–AAFE–ABAFE path, critical points arise from the cooperation of strain energy and mechanical sliding force. During the ACAFE–ADFE sliding process, phase transition relies on the combined effect of strain energy and mechanical sliding force. At the ADFE–ACAFE point, the transition is primarily driven by the combined action of interlayer interaction energy and mechanical sliding force. This theoretical work not only establishes a feasible approach for achieving a reversible AFE–FE–AFE phase transition, but also offers valuable insights for the design of novel volatile devices. [ABSTRACT FROM AUTHOR]

Wheat is one of the most important food crops globally, and understanding the regulation of grain size is crucial for wheat breeding to achieve a higher grain yield. MicroRNAs (miRNAs) play vital roles in plant growth and development. However, the miRNA-mediated mechanism underlying grain size regulation remains largely elusive in wheat. Here, we report the characterization and functional validation of a miRNA, TamiR397a, associated with grain size regulation in wheat. The function of three TaMIR397 homoeologs was determined through histochemical β-glucuronidase-dependent assay. MiRNA expression was detected using quantitative reverse transcription polymerase chain reaction (qRT-PCR), and the function of TamiR397a was validated through its transgenic overexpression and repression in wheat. It was found that TaMIR397-6A and TaMIR397-6B encode active TamiR397a. The expression profiling indicated that TamiR397a was differentially expressed in various tissues and gradually up-regulated during grain filling. The inhibition of TamiR397a perturbed grain development, leading to a decrease in grain size and weight. Conversely, the overexpression of TamiR397a resulted in increased grain size and weight by accelerating the grain filling process. Transcriptome analysis revealed that TamiR397a regulates a set of genes involved in hormone response, desiccation tolerance, regulation of cellular senescence, seed dormancy, and seed maturation biological processes, which are important for grain development. Among the down-regulated genes in the grains of the TamiR397a-overexpressing transgenic plants, 11 putative targets of the miRNA were identified. Taken together, our results demonstrate that TamiR397a is a positive regulator of grain size and weight, offering potential targets for breeding wheat with an increased grain yield. [ABSTRACT FROM AUTHOR]

Two-dimensional metal–organic frameworks (2D MOFs) as an ideal prototype material for the electrocatalytic oxygen evolution reaction (OER) can expose more metal active sites due to their ultrathin 2D structure. Herein, a two-dimensional Co3BDC6Py3DMF1 (termed Co MOF-Py3, BDC = 1,4-benzene dicarboxylic acid, Py = pyridine, and DMF = N,N-dimethylformamide) catalyst was prepared by a solvothermal bottom-up method by introducing pyridine to replace the triethylenediamine organic coordination in three-dimensional (3D) Co2(BDC)2(DABCO)·4DMF·H2O (termed Co MOF, DABCO = 1,4-diazabicyclo[2.2.2]octane). Compared to the 3D columnar Co MOF, the overpotential of ultrathin 2D nanosheet Co MOF-Py3 at 10 mA cm−2 decreased by 55 mV to 307 mV, and the Tafel slope was 52.14 mV dec−1. To further improve the catalytic capability of Co MOF-Py3, the Fe element was introduced into Co MOF-Py3 by impregnation to obtain a Co3Fe1 MOF-Py3 catalyst, which exhibited excellent OER performance with a low overpotential of 269 mV at 10 mA cm−2 and a small Tafel slope of 45.29 mV dec−1. Structural characterization reveals that the addition of a specific quantity of pyridine could completely replace the triethylenediamine ligands, thus leading to structural reconfiguration of the entire MOF, resulting in a structural alteration from 3D to 2D and enhancing the number of metal active sites to catalyze the OER. [ABSTRACT FROM AUTHOR]

Nowadays, two-dimensional (2D) materials with Janus structures evoke much attention due to their unique mechanical and electronic properties. In this work, Janus Pma2-Si2XY (X/Y = S/Se/Te, X ≠ Y) ferroelectric monolayers are firstly proposed and systematically investigated by first-principles calculations. These monolayers exhibit remarkable mechanical properties, including small Young's modulus values, negative Poisson's ratios (NPRs) and large critical strains, reflecting their exceptional flexibility and stretchability. More strikingly, the novel structures of Si2STe and Si2SeTe also endow them with in-plane spontaneous polarization (Ps) and low energy barrier for phase transition, with Ps and energy barrier values being 1.632 × 10−10 C m−1 and 159 meV for Si2STe and 1.149 × 10−10 C m−1 and 196.6 meV for Si2SeTe. The ab initio molecular dynamics (AIMD) simulations reveal high Curie temperatures (Tc) for Si2STe and Si2SeTe, ranging between 1300 K and 1400 K. Additionally, Si2XY monolayers exhibit high anisotropic carrier mobility (∼103 cm2 V−1 s−1) and an extraordinary light absorption coefficient (∼105 cm−1). Our research not only broadens the family of 2D Janus ferroelectric materials, but also demonstrates their potential applications in nanomechanical, nanoelectronic and optoelectronic devices. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) van der Waals (vdW) heterostructures with spontaneous intrinsic ferroelectrics play an essential role in ferroelectric memories. Also, the reversal of polarized directions induces band alignment transitions among different types to provide a new path for multifunctional devices. In this work, the structural and electronic properties of 2D VS2/Ga2O3 vdW heterostructures under different polarizations were investigated using first-principles calculations with the vdW correction of the DFT-D2 method. The results reveal that the polarized direction of a 2D Ga2O3 monolayer can cause a distinct band structure reversion from a metal to a semiconductor due to the shift of band alignment induced by the interlayer charge transfer. Moreover, the VS2/P↑ Ga2O3 heterostructures retain type-I and type-II band alignments in the majority and minority channel, respectively, under an external electric field. Interestingly, applying the external electric field for VS2/P↓ Ga2O3 heterostructures can lead to a transition from type-II to type-I in the majority channel, and from type-II to type-III in the minority channel. Our work provides a feasible way to realize 2D VS2/Ga2O3 vdW heterostructures for potential applications in ferroelectric memories and electrostatic gating dependent multiple band alignment devices. [ABSTRACT FROM AUTHOR]

Based on the advantage of rapid net-shape fabrication, laser powder bed fusion (LPBF) is utilized to process B4C-reinforced Ti composites. The effect of volumetric energy density (VED) on the relative density, microstructural evolution, tensile properties and wear behaviors of B4C-reinforced Ti composites were systematically investigated. The LPBF-ed samples with high relative density (>99%) can be achieved, while the pores and un-melted powders can be observed in the sample owing to the low energy input (33 J/mm3). The additive particulates B4C were transformed into needle-like TiB whiskers with nano-scale while C dissolved in the Ti matrix. Fine-scale grains (<10 μm) with random crystallographic orientation can be achieved and the residual stress shows a downtrend as the VED increases. Through the analysis of the tensile and wear tests, the sample at 61 J/mm3VED showed a good combination of strength and wear performance, with an ultimate tensile strength of 951 MPa and a wear rate of 3.91 × 10−4 mm3·N−1m−1. The microstructural evolution in VED changes and the corresponding underlying strengthening mechanisms of LPBF-ed Ti + B4C composites are conducted in detail. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the value of new gastric cancer screening score system for risk assessment of gastric precancerous lesions. Methods: A total of 520 patients were enrolled after the examination of endoscopy at Endoscopy Center, Department of Gastroenterology, from June 2018 to December 2021. The patients were divided into three groups according to age, gender, serum helicobacter pylori antibody test, pepsinogen I (PGI), pepsinogen II (PGII), pepsinogen I/II ratio (PGR) and gastrin-17 test results before endoscopy: Group A defined as low-risk group (0-11 points), Group B defined as middle-risk group (12-16 points), Group C defined as high-risk group (17-23 points). The detection rates of gastric cancer and atrophic gastritis in three groups were analyzed. According to the range and degree of atrophy/intestinal metaplasia, patients were divided into five groups on the basis of OLGA/OLGIM staging system. The levels of PG I, PG II and PGR were compared between different groups, and the correlation between new gastric cancer screening score system and OLGA/OLGIM staging system were evaluated. Statistical analysis was accomplished by ANOVA, chi-square test and Gamma coefficient analysis. Results: A total of 520 patients were enrolled. 268 patients were classified into group A,222 patients into group B and 30 patients into group C, respectively. According to the pathological results, 281 cases were non-atrophic gastritis, 230 cases atrophic gastritis and 9 cases gastric cancer. For OLGA staging system, 281 patients were divided into stage-0 group, 121 patients into stage-I group, 72 patients into stage-II group, 33 patients into stage-III group and 13 patients into stage-IV groups. The PGI and PGR level correlated inversely with the rising OLGA stages (F = 3.028, p =.016, F = 6.036, p <.001). For OLGIM staging system, 252 patients were divided into stage-0 group, 137 patients into stage-I group, 80 patients into stage-II group, 36 patients into stage-III group and 15 patients into stage-IV group. The PGR level correlated inversely with the rising OLGIM stages (F = 3.466, p＝.007). The detection rates of gastric cancer and atrophic gastritis in Group C were much higher than other groups. (X2 = 14.727, p <.001; X2 = 51.280, p <.001). Gamma coefficient analysis showed significant correlations between OLGA/OLGIM and the new gastric cancer screening score system (p <.001). Conclusions: The new gastric cancer screening score system is closely linked with histological OLGA/OLGIM staging system in the risk assessment of gastric precancerous lesions. The role of new gastric cancer screening score system in future gastric precancerous lesions screening and high risk population identifying was promising. [ABSTRACT FROM AUTHOR]