Influence of Strengthening Material Behavior and Geometry Parameters on Mechanical Behavior of Biaxial Cruciform Specimen for Envelope Material.

The stratospheric airship envelope material is operated in biaxial stress, so it is necessary to study the in-plane biaxial tensile strength. In this paper, a theoretical model is developed to evaluate the mechanical properties of in-plane biaxial specimens. Being applied to the finite element analysis, the theoretical model is employed to evaluate the influence of strengthening material behavior (E*) and geometry parameters on the mechanical behavior in the central. The follows results are drawn: (i) smaller the length of the central region (Lcen), E* and larger the central region corner radius (r) contribute to smaller coefficient of variation (CV); (ii) smaller Lcen and larger E* contribute to smaller stress concentration factor (k), k in the limit state of r is larger than that in other conditions. (iii) The CV and k under stress ratio of 1:1 are smaller than those under other stress ratios. The study can provide a useful reference for the design of biaxial specimens.

Large-Strain Hyperelastic Constitutive Model of Envelope Material under Biaxial Tension with Different Stress Ratios.

This paper reports the biaxial tensile mechanical properties of the envelope material through experimental and constitutive models. First, the biaxial tensile failure tests of the envelope material with different stress ratio in warp and weft directions are carried out. Then, based on fiber-reinforced continuum mechanics theory, an anisotropic hyperelastic constitutive model on envelope material with different stress ratio is developed. A strain energy function that characterizes the anisotropic behavior of the envelope material is decomposed into three parts: fiber, matrix and fiber⁻fiber interaction. The fiber⁻matrix interaction is eliminated in this model. A new simple model for fiber⁻fiber interaction with different stress ratio is developed. Finally, the results show that the constitutive model has a good agreement with the experiment results. The results can be used to provide a reference for structural design of envelope material.

Cytokine changes in response to TPO receptor agonist treatment in primary immune thrombocytopenia.

Thrombopoietin receptor agonists (TPO-RAs) have been clinically used in primary immune thrombocytopenia (ITP) with favorable outcomes, while their effect on cytokine regulation in ITP remains unknown. In the present study, plasma and mRNA expression levels of interleukin (IL)-2, interferon gamma (IFN-γ), IL-4, IL-17A, and transforming growth factor-ß1 (TGF-ß1) were determined by ELISA and real-time quantitative PCR in 26 corticosteroid-resistant/relapsed ITP patients receiving eltrombopag or rhTPO therapy and 15 healthy controls (HCs). Results showed that plasma and mRNA levels of IL-2, IFN-γ, IL-4, and IL-17A in ITP patients did not change significantly after TPO-RA treatment, whereas TGF-ß1 levels increased remarkably. The pre- and post-treatment plasma and mRNA levels of IFN-γ and IL-2 were significantly higher, while the pre- and post-treatment IL-4 levels as well as the pre-treatment TGF-ß1 levels were remarkably lower in ITP patients compared with HCs. There was no significant difference in TGF-ß1 levels between TPO-RA-treated ITP patients and HCs. No statistical difference was found in plasma levels of IL-17A between ITP patients before or after treatment and HCs. However, the pre- and post-treatment mRNA expression of IL-17A and retinoic orphan receptor (ROR) γt in ITP patients were higher than that in HCs. Overall, these findings indicated that TPO-RA treatment could promote the secretion of TGF-ß1, while it could not correct the Th1 and Th17 polarization in ITP patients. This study might improve our understanding of the mechanism of action of TPO-RAs and provide important information for optimizing therapeutic strategies for ITP.

Tri-band transparent conductive coating of indium tin oxide.

A tri-band transparent conductive indium tin oxide (In2O3:Sn, ITO) film for the visible, near-infrared (NIR) and mid-infrared (MIR) was deposited on a sapphire substrate by radio frequency (RF) magnetron sputtering. Deposition parameters, including RF power, substrate temperature, and oxygen flow rate, were optimized to improve the optical property without reducing the conductivity of the film by maximizing the Hall mobility and minimizing the carrier concentration. Films deposited at optimized conditions exhibit a Hall mobility of ∼20 cm2 V-1 s-1, a carrier concentration of ∼4.99×1020 cm-3, and a sheet resistance of 61.2 Ω/sq. Average transmissions of these films are 81.40% in the 0.4-1.6 µm region and 60.81% in the 3.0-5.0 µm region. An index-matching stack of MgF2 was developed, improving the transmittance to 90.55% and 73.20% in the regions above, respectively. These results make ITO film a promising alternative material to conventional metal mesh for missile domes shielding electromagnetic waves.