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An integral sliding mode fault‐tolerant control method is proposed to deal with faults with matched uncertainties, unmatched uncertainties, and input saturation. Integral sliding mode, control allocation, and parameter identification are included in this method. The Lyapunov stability conditions of the integral sliding mode control for uncertainties and input saturation, respectively, are obtained, which denote the robustness extent of the controller. The direct method for control allocation is improved by adding a judgement before calculating for each facet. Finally, the fault‐tolerant scheme is applied to a six‐wheel spacecraft and simulations are given to show its effectiveness.

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The purpose of this study was to explore the triphasic mechanical properties of osteoarthritic cartilage with different pathological grades. First, samples of cartilage from rabbits with different stages of osteoarthritis (OA) were graded. Following this, the cartilage was strained by a swelling experiment, and changes were measured using a high-frequency ultrasound system. The result, together with fixed charge density and water volume fraction of cartilage samples, was used to estimate the uniaxial modulus of the cartilage tissue, based on a triphasic model. For the control cartilage samples, the uniaxial elastic modulus on the cartilage surface was lower than those in the middle and deep layers. With an increase in the OA grade, the uniaxial elastic modulus of the surface, middle and deep layers decreased. A significant difference was found in the surface elastic modulus of different OA grades (P<0.01), while no significant differences were identified for OA cartilages of Grades 1 and 2 in the middle and deep layers (P<0.01). Compared with Grades 1 and 2, there was a significant reduction in the elastic modulus in the middle and deep layers of Grade 3 OA cartilage (P<0.05). Overall, this study may provide a new quantitative method to evaluate the severity of OA using the mechanical properties of cartilage tissue.

Highly transparent cerium-doped yttria ceramics were fabricated via a pressureless sintering method with an addition of 10 at.% La 2 O 3 and 1 at.% ZrO 2 as a binary sintering additive. With an increase in the Ce doping concentration from 0 to 3 at.%, the optical absorption edge of yttria ceramics exhibited a significant red shift from 290 to 380 nm as a result of the 4f-5d transition of Ce 3+ and the charge transfer of Ce 4+ (i.e., Ce 4+ +e -→Ce 3+ ). For a 2-mm thick sample doped with 3 at.% Ce, the total ultraviolet radiation (UV) transmittance (220-400 nm) is only 1.7%, indicating a nearly complete UV absorption. Meanwhile, the specimens possess high in-line transmittance levels in both the visible and the infrared regions (i.e., >70% at 450 nm and ∼80% at 1100 nm). Additionally, the present specimens were confirmed to have good enough mechanical strength levels (∼165 MPa) and thermal conductivity (∼5 W/m⋅K), which are comparable or even better compared to those of previously reported transparent yttria ceramics. The results of this work indicate that cerium-doped transparent yttria ceramics are promising candidate materials for full-band UV-shielding window applications.

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