Elastic stretchability and function density represent two key figures of merits for stretchable inorganic electronics. Various design strategies have been reported to provide both high levels of stretchability and function density, but the function densities are mostly below 80%. While the stacked device layout can overcome this limitation, the soft elastomers used in previous studies could highly restrict the deformation of stretchable interconnects. Here, we introduce stacked multilayer network materials as a general platform to incorporate individual components and stretchable interconnects, without posing any essential constraint to their deformations. Quantitative analyses show a substantial enhancement (e.g., by ~7.5 times) of elastic stretchability of serpentine interconnects as compared to that based on stacked soft elastomers. The proposed strategy allows demonstration of a miniaturized electronic system (11 mm by 10 mm), with a moderate elastic stretchability (~20%) and an unprecedented areal coverage (~110%), which can serve as compass display, somatosensory mouse, and physiological-signal monitor.

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Anisotropic fibrous networks, especially transverse isotropic fibrous networks, are widely used to model the microstructures of biological tissues, polymer gels, fibrous thermal insulations, and other fibrous materials. In this letter, we build a three-dimensional transverse isotropic fibrous network model and study its mechanical properties along the through-thickness direction. We propose a measurement of anisotropy for transverse isotropic fibrous networks and then study the influence of anisotropy on the networks' mechanical properties, including its elastic modulus, maximum elongation, and stress–strain curve, by means of finite-element simulation. We also study theoretically the influence of anisotropy on maximum elongation. We find that as the anisotropy of the networks becomes stronger, the elastic modulus decreases and the maximum elongation increases, indicating a transition in mechanical properties from brittle to ductile. We identify this transition as the “ductile–brittle transition.” This transition can help guide the design and regulate the mechanical properties of a transverse isotropic fibrous network.

The pressure losses of the hot primary-air pipe system have a great influence on the economic operation of a pulverizing system. To balance the flow resistance for different branches, Fluent was applied to simulate flow dynamics and pressure drop for a hot primary-air pipe system, and two improvement schemes were proposed. Numerical simulation reveals that for the original configuration, the flow losses of each branch are quite different, and the large resistance of some branches is mainly caused by pipe tees. After improvement, the flow regime has been significantly polished, and the total pressure drop of different branches is greatly reduced. Compared with the original configuration, the total pressure loss of branch B and branch D in case 2 is reduced by 65% and 53%, respectively, then an approximately equal pressure drop of each branch is achieved after structure improvement.