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Uniaxial compression tests were carried out on mullite fiber reinforced silica aerogel composites in the out-of-plane direction. Influences of different ultimate strains and thermal exposure temperatures on the compression springback behavior and deformation recovery capability were investigated. Internal mechanisms based on the microstructure morphology changes were explained. Phenomenological mechanical models were established respectively for the deformation behavior in the loading and unloading stages. The results show that the compression springback behavior of mullite fiber reinforced silica aerogel composites exhibits nonlinear characteristics. The greater the ultimate strain, the worse the deformation recovery capability. High temperature thermal exposure pre-treatment has an effect on the compression springback property, the higher the thermal exposure temperature, the worse the deformation recovery capability. The aggregation of matrix particle-cluster structure and the formation and collapse of the large size holes are main causes. The phenomenological mechanical model can be used to describe the stress-strain curve of the composites during loading and unloading. The fitting results are in good agreement with the experimental data.

In this paper, a fast method to generate a constant-modulus (CM) waveform for a multiple-input, multiple-output, (MIMO) radar is proposed. To simplify the optimization process, the design of the transmit waveform is decoupled from the design of transmit beamformers (TBs) and subpulses. To further improve the computational efficiency, the TBs' optimization is conducted in parallel, and a linear programming model is proposed to match the desired beampattern. Additionally, we incorporate the perturbation vectors into the TBs' optimization so that the TBs can be adjusted to satisfy the CM constraint. To quickly generate the CM subpulses with the desired range-compression (RC) performance, the classical linear frequency modulation (LFM) signal and non-LFM (NLFM) are adopted as subpulses. Meanwhile, to guarantee the RC performance of the final angular waveform, the selection of LFM signal parameters is analyzed to achieve a low cross-correlation between subpulses. Numerical simulations verify the transmit beampattern performance, RC performance, and computational efficiency of the proposed method. [ABSTRACT FROM AUTHOR]

The quantification of the interactions between biomolecules and materials interfaces is crucial for design and synthesis functional hybrid bionanomaterials for materials science, nanotechnology, biosensor, biomedicine, tissue engineering, and other applications. Atomic force spectroscopy (AFM)-based single-molecule force spectroscopy (SMFS) provides a direct way for measuring the binding and unbinding forces between various biomolecules (such as DNA, protein, peptide, antibody, antigen, and others) and different materials interfaces. Therefore, in this review, we summarize the advance of SMFS technique for studying the interactions between biomolecules and materials interfaces. To achieve this aim, firstly we introduce the methods for the functionalization of AFM tip and the preparation of functional materials interfaces, as well as typical operation modes of SMFS including dynamic force spectroscopy, force mapping, and force clamping. Then, typical cases of SMFS for studying the interactions of various biomolecules with materials interfaces are presented in detail. In addition, potential applications of the SMFS-based determination of the biomolecule-materials interactions for biosensors, DNA based mis-match, and calculation of binding free energies are also demonstrated and discussed. We believe this work will provide preliminary but important information for readers to understand the principles of SMFS experiments, and at the same time, inspire the utilization of SMFS technique for studying the intermolecular, intramolecular, and molecule-material interactions, which will be valuable to promote the reasonable design of biomolecule-based hybrid nanomaterials.