This work presents first-principles calculations on the surface and defect impact upon zinc stannate (ZS) materials with perovskite bulk structures. The structure and electronic properties of both a perfect 001 surface and surfaces with a point defect of ZS were investigated by means of density functional theory calculations. The cohesive energies of a perfect 001 surface and those with O, Sn, or Zn defects were decreased compared with that of bulk ZS. Oxygen defects on the 001 surface of ZS formed more easily than others based on the obtained cohesive energy and defect formation energy. The electronic properties close to the Fermi levels of bulk ZS materials were mainly controlled by the O 2p and Sn 5s orbitals. The formation of vacancy on the 001 surface of ZS changed the band structure and band gap compared with that of the bulk. The modulation mechanism was explored by means of structure transformation, band structure, and density of states analysis.
Background: Chronic obstructive pulmonary disease (COPD) is a familiar disease, and owns high morbidity and mortality, which critically damages the health of patients. Ubiquitin-specific peptidase 8 (USP8) is a pivotal protein to join in the regulation of some diseases. In a previous report, it was determined that USP8 expression is down-regulated in LPS-treated BEAS-2B cells, and USP8 restrains inflammatory response and accelerates cell viability. However, the regulatory roles of USP8 on ferroptosis in COPD are rarely reported, and the associated molecular mechanisms keep vague. Objective: To investigate the regulatory functions of USP8 in COPD progression. Material and Methods: The lung functions were measured through the Buxco Fine Pointe Series Whole Body Plethysmography (WBP). The Fe level was tested through the Fe assay kit. The protein expressions were assessed through western blot. The levels of tumor necrosis -factor-α, interleukin 6, and interleukin 8 were evaluated through enzyme-linked immunosorbent serologic assay. Cell viability was tested through CCK-8 assay. Results: In this work, it was discovered that overexpression of USP8 improved lung function in COPD mice. In addition, overexpression of USP8 repressed ferroptosis by regulating glutathione peroxidase 4 and acyl-CoA synthetase long-chain family 4 expressions in COPD mice. Overexpression of USP8 suppressed inflammation in COPD mice. Furthermore, overexpression of USP8 suppressed ferroptosis in COPD cell model. At last, it was verified that overexpression of USP8 accelerated ubiquitin aldehyde-binding protein 1 (OTUB1)/solute carrier family 7 member 11 (SLC7A11) pathway. Conclusion: This study manifested that overexpression of USP8 restrained inflammation and ferroptosis in COPD by regulating the OTUB1/SLC7A11 signaling pathway. This discovery hinted that USP8 could be a potential target for COPD treatment.
A simple and accurate small-signal model for 40 nm gatelength MOSFET device is proposed in this paper. Semi-analytical extraction method is performed by S-parameter analysis based on the proposed equivalent circuit of MOSFET for high-frequency operation. Simulated and measured results of 40 nm MOSFET with a 5×0.04×4 μm gatewidth (unit gate width × unit gate length × number of gate finger) are compared and good agreement has been obtained up to 40GHz.
Stacked crystal film bulk acoustic wave filters (SCFBAF) have obvious advantages over other filters (such as ladder-type filters, coupled resonator filters, etc.), including low insertion loss, small size and high stop-band attenuation, working in super high operating frequencies, etc. This paper presents the design and simulation of a six layers of SCFBAF. Structure of SCFBAF is illustrated and properties of three kinds of piezoelectric materials (lead zirconate titanate, zinc oxide and aluminum nitride) are compared. Amplitude-frequency curves of SCFBAF with different piezoelectric materials and thicknesses are obtained by using ANSYS 11.0. Based on the simulation results, analyses of performances of SCFBAF are stated. Finally relationships among performance, thickness and materials are concluded. The research results are valuable for design, fabrication and measurement of next generation complex RF MEMS filters.
Abstract SmTaO 4 , Sm 3 TaO 7 and SmTa 3 O 9 ceramics were prepared via a high temperature solid-state reaction. The results show that the phase structures of the SmTaO 4 ceramics are a monoclinic phase (space group: I2 (5)), the Sm 3 TaO 7 ceramics are an ordered orthorhombic phase (space group: Ccmm), and the SmTa 3 O 9 ceramics are an orthorhombic phase (space group: Cmmm). Macromolecular and crystal structures of Sm 3 TaO 7 and SmTa 3 O 9 are more complex than those of SmTaO 4 , which can enhance phonon scattering and reduce thermal conductivity. Compared with those of SmTaO 4 and SmTa 3 O 9 , Sm 3 TaO 7 has the smallest grain size, indicating that a small grain size has an effect on strength and ensures material stability. Because of a distorted TaO 6 octahedron and a high concentration of cation vacancy in the lattice of SmTa 3 O 9 , its thermal conductivity increases with increasing temperature. Compared with that of 7–8 YSZ, Sm 3 TaO 7 has a low thermal conductivity (1.3–1.7 W·m −1 ·K −1 at 100 °C–900 °C), and its minimum thermal conductivity is nearly 30% lower than that of YSZ. The Sm 3 TaO 7 ceramics have the highest TECs at approximately 9.82 × 10 −6 K −1 at 1200 °C, which is close to that of 7–8 YSZ (approximately 10 × 10 −6 ). This indicates that Sm 3 TaO 7 has the potential to be employed as a thermal barrier coating.
Electroless plating of Ni-Fe-B alloy on poly(ethylene terephthalate) (PET) fabrics with a novel activiting method was investigated. The activiting steps were immersion the samples to a methanol solution (10 mL) containing 2 g nickel acetate for 30 min, then immersed in an other methanol solution (10 mL) containing 1g potassium borohydride to adequate reaction. Low-cost activator was gained by potassium borohydride reduce nickel acetate on the PET fabric surface. Scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) were used to characterize morphology, structure, composition of the activated layer and Ni-Fe-B coating on the PET fabric. The results indicate that Ni-Fe-B alloy deposits by the electroless deposition were continuous and uniform.
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