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In recent years, flexible functional materials have attracted increasing interest, but there is a lack of designing mechanisms of flexibility design with superstructures. In traditional engineering mechanics, the maximum bending strain (MBS) was considered universal for describing the bendable properties of a given material, leading to the universal designing method of lowering the dimension such as thin membranes designed flexible functional materials. In this work, the MBS was found only applicable for materials with uniformly distributed Poisson's ratio, while the MBS increases with the thickness of the given material in case there is a variation Poisson's ratio in different areas. This means the MBS can be enhanced by certain Poisson's ratio design in the future to achieve better flexibility of thick materials. Here, the macroscopic freestanding inorganic functional BaTiO3:Sm3+ (BTO:S) nanofiber membranes, which have a nonconstant Poisson's ratio response on stress/strain for creating nonuniformly distributed Poisson's ratio, were proven applicable for designing larger MBS and lower Young's modulus for flexible functional materials. [ABSTRACT FROM AUTHOR]

Cu6Sn5 intermetallic compound (IMC) formed at Sn/polycrystalline Cu interface after liquid–solid reaction generally presents scallop‐like morphology and tends to ripen into large‐sized grains with texture feature. In this paper, the formation of laminar Cu6Sn5 on nanocrystalline (NC) Cu by interfacial reaction with liquid Sn is reported. The laminar Cu6Sn5 consists of stacked ultrafine grains, thickened in the manner of "nibbling" the NC Cu and shows randomly distributed orientations. With extended reaction time, the top Cu6Sn5 grains that are exposed to the liquid Sn transform into long‐rod‐like grains all along their <0001> direction, while the bottom Cu6Sn5 grains remain laminar and ultrafine. The formation and growth mechanism of the novel laminar Cu6Sn5 at the Sn/NC Cu interface as well as that of the rod‐like Cu6Sn5 are revealed from the aspects of atomic diffusion, nucleation, and grain merging. It is also found that the Cu3Sn IMC generated at the laminar Cu6Sn5/NC Cu interface is much thinner than that at the classic scallop‐like Cu6Sn5/polycrystalline Cu interface, showing no obvious formation of Kirkendall voids. [ABSTRACT FROM AUTHOR]

The temporal response of CdZnTe (CZT) detectors is measured under different X-ray flux, spectra, and detector bias conditions. A comprehensive model has been developed to investigate the detector response under these conditions. The calculations have been compared with our measured results. Reasonable qualitative agreement is shown between the model and measurement results. This model provides a powerful tool to understand the detector temporal response, photocurrent dependence on the irradiation intensity, bias voltage, and defect characteristics. Understanding the detector response from a microscopic level can provide a guide to improve material properties and detector device design. Index Terms--CdZnTe detector, medical imaging, polarization, temporal response.

The dynamic modeling and coupling effect of a space robot are complex when the flexible manipulator and solar panels are considered. This paper investigates the dynamic coupling effect and control of a flexible space robot with flexible manipulators and flexible panels. The equations of motion are derived for the robot model both of the rigid-flexible type and flexible-flexible type. The flexible space robot dynamic model is verified by comparison with the results generated by the ADAMS software, for which good agreement has been obtained. The dynamic coupling matrix of the flexible space robot is derived based on the dynamic model. The effects of the central rigid body mass and the joints angle on the dynamic coupling are analyzed. A control method is proposed to manipulate the flexible space robot based on the system dynamic model. The multiple-impulse robust (MIR) input shaper is used to suppress the vibration of flexible structures in the proposed controller. Appropriate design parameter and frequency scaling factor are selected for the MIR input shaper to suppress the flexible vibration. The flexible space robot control is conducted to illustrate the effect of the proposed controller. It is shown that the proposed control method can realize the desired joints manipulation, while suppressing the vibration of the flexible manipulators and flexible panels. [ABSTRACT FROM AUTHOR]

Photon-counting computed tomography (PCCT) may dramatically benefit clinical practice due to its versatility such as dose reduction and material characterization. However, the limited number of photons detected in each individual energy bin can induce severe noise contamination in the reconstructed image. Fortunately, the notable low-rank prior inherent in the PCCT image can guide the reconstruction to a denoised outcome. To fully excavate and leverage the intrinsic low-rankness, we propose a novel reconstruction algorithm based on quaternion representation (QR), called low-rank quaternion reconstruction (LOQUAT). First, we organize a group of nonlocal similar patches into a quaternion matrix. Then, an adjusted weighted Schatten-p norm (AWSN) is introduced and imposed on the matrix to enforce its low-rank nature. Subsequently, we formulate an AWSN-regularized model and devise an alternating direction method of multipliers (ADMM) framework to solve it. Experiments on simulated and real-world data substantiate the superiority of the LOQUAT technique over several state-of-the-art competitors in terms of both visual inspection and quantitative metrics. Moreover, our QR-based method exhibits lower computational complexity than some popular tensor representation (TR) based counterparts. Besides, the global convergence of LOQUAT is theoretically established under a mild condition. These properties bolster the robustness and practicality of LOQUAT, facilitating its application in PCCT clinical scenarios. The source code will be available at https://github.com/linzf23/LOQUAT.