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Abstract On the basis of first-principles calculations, we investigate the electronic and magnetic properties of 1T phase chromium sulfide halide CrXY (X = O, S, Se; Y = Cl, Br, I) monolayers in CrCl2 structure with the P $$\overline{3}$$ 3 ¯ m1 space group. Except for the CrOI monolayer, all CrXY monolayers are stable and ferromagnetic semiconductors. Our results show that the ferromagnetic coupling is dominated by the kinetic exchange between the empty e g -orbital of Cr atoms and the p-orbital of anions under the three-fold rotational symmetry. In this context, the coupling strength allows for being greatly enhanced by turning the nature of Cr–X bonds, i.e., increasing the covalent contribution of the bonds by minimizing the energy difference of the coupled orbitals. As we illustrate for the example of CrOY, the Curie temperature (T c) is nearly tripled by substituting O by S/Se ion, eventually reaching the highest T c in CrSeI monolayer (334 K). The high stabilities and Curie temperature manifest these monolayer ferromagnetic materials feasible for synthesis and applicable to 2D spintronic devices.

The amorphous silicon dioxide-silicon (a-SiO2/Si) interface is an important part of silicon devices. It is difficult to avoid interface defects during the device production process. The passivated interface defects will undergo a depassivation reaction with the protons in the silicon dioxide generated by irradiation and convert to positively charged dangling bonds, thereby affecting device performance. In engineering practice, there is a final passivation layer on top of a-SiO2, and it is inevitable to introduce stress on the a-SiO2/Si interface. Therefore, studying the depassivation reaction mechanism of a-SiO2/Si interface defects under stress is of great significance to understand the performance degeneration in real devices. By using molecular dynamics and first-principles calculations, Pb defects at a-SiO2/Si (111) interface and Pb1 defects at a-SiO2/Si (100) interface are selected in this work to investigate the effect of stress on their depassivations. Biaxial strains are applied to the models, energy curves of the depassivation reactions under stress are calculated using the CI-NEB (Climbing Image Nudged Elastic Band) method, and transition states are identified. According to the Harmonic Transition State Theory (HTST), the reaction rate constants of the depassivation reactions of Pb and Pb1 defects at a certain temperature can be obtained. Finally, the relative concentration curves during depassivation reactions of PbH and Pb1H under stress and room temperature are obtained. Detailed data and figure analyses are presented to demonstrate differences between the two typical interface defects when depassivating under stress. Appropriate degrees of interface stress are proved to extend the depassivation time of defects, therefore prolonging the service life of devices.

Abstract Background Immune cell infiltration and neuroinflammation are heavily associated with spinal cord injury (SCI). C-C motif chemokine ligand 2/C-C chemokine receptor type 2 (CCL2/CCR2) axis has been identified as a critical role player during the invasion of immune cells to lesions in many diseases. γδ T cells, a subgroup of T cells, manage the course of inflammation response in various diseases; however, it remains unknown whether γδ T cells are recruited to injury site through CCL2/CCR2 signaling and exert the regulation effect on neuroinflammation after SCI. Methods Basso Mouse Scale (BMS), regularity index, cadence, max contact area, and motor-evoked potential testing (MEP) were measured to determine the neurological function recovery after spinal cord injury. Nissl staining was performed to identify the number of surviving motor neurons at lesion epicenter. Immunofluorescence, Western blot, enzyme-linked immunosorbent assays (ELISA), and quantitative real-time polymerase chain reaction (QRT-PCR) also were employed to evaluate the expression of associated proteins and genes. Results In this study, we demonstrated that TCRδ−/− mice present improved neurological recovery after SCI. γδ T cell recruitment to the SCI site was significantly reduced and motor functional improvement enhanced in CCL2−/− and CCR2−/− mouse strains. Furthermore, reconstitution of TCRδ−/− mice with γδ T cells extracted from CCR2−/− mice also showed similar results to CCL2 and CCR2 deficient mice. Conclusions In conclusion, γδ T cell recruitment to SCI site promotes inflammatory response and exacerbates neurological impairment. CCL2/CCR2 signaling is a vital recruitment mechanism of γδ T cells to the SCI site, and it may be taken as a novel therapeutic target for future SCI.

A semi-lumped reconfigurable on-chip bandpass filter with GaAs pHEMT technology is presented in this paper. Three order tunable bandpass filter is designed with serial lumped capacitors, parallel resonators, and reconfigurable components. The operating bands are adjusted by field effect transistors and its corresponding gate bias circuits with GaAs technology. The semi-lumped topology, intending to reduce the size of the circuit, is employed to construct the parallel resonators, which are implemented with short-ended stubs and metal-insulator-metal capacitors. The equivalent circuit model is built to interpret the mechanism of the on-chip reconfigurable bandpass filter. Compared with the traditional tunable filters, an ultra-compactness feature and low insertion loss are obtained with the proposed design. The size of the on-chip filter is only 0.8×1.07 mm2, which is equivalent to 0.08×0.11 λg2 at 10 GHz. The presented filter is reconfigurable in two frequency bands, one is centered at 10 GHz with a fraction bandwidth (FBW) of 24.94% and the other is operated at 8.8 GHz with a FBW of 13.35%. The tuning range of the FBW is 30.6%. Good agreements are observed between the simulated and measured S-parameters.

Emergency communication has the characteristics of strong sudden and uncertainty, to meet the requirements of flexible network planning, on the basis of different characteristics of diverse layered network to accomplish the modeling description, apply the deep reinforcement learning algorithm to implement network topology planning task, and enhance the generation efficiency through the algorithm optimization. According to the business characteristics and strategies to allocate the emergency communications network business resources, then achieve the complete emergency communications network planning, finally the emergency communications network planning model and the method is verified with high rationality and efficiency by a sample simulation, which provides a certain reference for the emergency communications network planning, which provides a certain reference for the emergency communications network planning.