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Distributed precision jamming (DPJ) is an efficient way to control the combined power spectrum (CPS) of both target and friendly devices in electronic warfare. However, the existing methods neglect the design of worst-case CPS performance, and a great challenge is posed in determining an appropriate Pareto parameter to protect the friendly devices in practice. To address these issues, this paper investigates the maximin design of wideband constant modulus (CM) waveform for DPJ. Specifically, a novel optimization problem is established by maximizing the minimum CPS of the target equipment, and the maximum CPS of friendly devices is controlled under a given threshold in the constraint. The resultant problem is nonconvex and nonsmooth, together with CM and numerous quadratic constraints. Two algorithms, which can start from an infeasible initial point, are proposed to tackle the problem approximated by the $l_{p}$-norm. The first algorithm resorts to the alternating direction method of multipliers (ADMM) framework, and each subproblem is obtained with a closed-form solution. The second algorithm merges the penalty distance (PD) method and manifold optimization. The crux of this approach is to obtain the closed-form Euclidean PD term via the Karush-Kuhn-Tucker conditions and leverage the Riemannian conjugate gradient (RCG) framework, and we name this algorithm PD-RCG. Numerical examples demonstrate the effectiveness of our proposed algorithms. Comparatively speaking, the ADMM-based algorithm has better performance in protecting the friendly devices, while the PD-RCG algorithm performs better on the computational efficiency and the worst-case CPS of the target equipment.

This paper investigates the robust cognitive joint design of transmit waveform and receive filter to improve the system performance of airborne multiple-input multiple-output (MIMO) radar. Considering the target Doppler frequency and spatial cone angle uncertainties are present, we formulate the averaged signal-to-clutter-plus-noise ratio (SCNR) as the optimization goal. Specifically, the averaged SCNR is maximized under only constant modulus constraint and that under constant modulus and similarity constraints. Four iterative optimization algorithms are developed to deal with the joint design problem. The first kind of iterative optimization algorithm is based on semidefinite programming (SDP) relaxation and randomization or rank-one decomposition techniques. The second kind of computational efficient iterative optimization algorithm utilizes the fractional programming and power method-like iteration. The proposed algorithms can achieve a monotonic output SCNR enhancement and are robust against the inaccuracies of target parameters. Several simulations results are implemented to validate the superiority of the proposed algorithms considering the output SCNR, space-time beampattern and computational complexity. [ABSTRACT FROM AUTHOR]

For sustain the release rate and prolong half-life of breviscapine in vivo, the breviscapine-loaded halloysite nanotubes complex was prepared. The breviscapine was encapsulated into halloysite nanotubes (HNTs) using a vacuum process. The complex were investigated by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), transmission electron microscope (TEM), X-ray diffraction (XRD) and fourier transform infrared spectroscopy(FT-IR). The formation of breviscapine-loaded HNTs complex was proved by the test results of SEM, DSC, TEM and IR analysise. The results confirmed that breviscapine was successfully loaded in the halloysite nanotubes. Additionally, the in vitro drug release of breviscapine from breviscapine-loaded HNTs complex was investigated, the result indicated this complex has apparent sustained-release effect.

To further solve spectrum congestion and improve spectrum utilization efficiency, we research a novel integrated radar communication and jamming (IRCJ) system based on a multi-input-multi-output (MIMO) platform in this study. We trade off the beampattern matching error, multiuser interference (MUI) energy, and spectrum matching error as the optimization cost function and design an integrated transmitted waveform that can detect radar targets, achieve high-speed downlink communication, and jam enemies simultaneously. Furthermore, we add a constant modulus constraint to ensure the unimodular property of the transmitted waveform. The proposed optimization problem is multivariable, non-convex, and quartic. To tackle this, we develop an iterative algorithm based on a cyclic manner and majorization-minimization (MM) framework. Finally, the simulation results verify the effectiveness of the proposed algorithm. [ABSTRACT FROM AUTHOR]