Information divergences are commonly used to measure the dissimilarity of two elements on a statistical manifold. Differentiable manifolds endowed with different divergences may possess different ...geometric properties, which can result in totally different performances in many practical applications. In this paper, we propose a total Bregman divergence-based matrix information geometry (TBD-MIG) detector and apply it to detect targets emerged into nonhomogeneous clutter. In particular, each sample data is assumed to be modeled as a Hermitian positive-definite (HPD) matrix and the clutter covariance matrix is estimated by the TBD mean of a set of secondary HPD matrices. We then reformulate the problem of signal detection as discriminating two points on the HPD matrix manifold. Three TBD-MIG detectors, referred to as the total square loss, the total log-determinant and the total von Neumann MIG detectors, are proposed, and they can achieve great performances due to their power of discrimination and robustness to interferences. Simulations show the advantage of the proposed TBD-MIG detectors in comparison with the geometric detector using an affine invariant Riemannian metric as well as the adaptive matched filter in nonhomogeneous clutter.
Significance This work demonstrates a structure–property correlation in metallic glasses for the community of amorphous solids. It associates geometrically unfavored motifs, i.e., those most ...disordered local polyhedral packing structures in a metallic glass, with the soft spots defined from the vibrational modes and correlates them with shear transformation zones composed of atoms with large nonaffine displacements. The statistical correlation established thus ties together the heterogeneity inherent in the amorphous structure with the spatial heterogeneity in the mechanical (elastic and plastic) properties of a metallic glass.
In a 3D model mimicking realistic Cu ₆₄Zr ₃₆ metallic glass, we uncovered a direct link between the quasi-localized low-frequency vibrational modes and the local atomic packing structure. We also demonstrate that quasi-localized soft modes correlate strongly with fertile sites for shear transformations: geometrically unfavored motifs constitute the most flexible local environments that encourage soft modes and high propensity for shear transformations, whereas local configurations preferred in this alloy, i.e., the full icosahedra (around Cu) and Z16 Kasper polyhedra (around Zr), contribute the least.
•Stable W/O/W emulsion containing 2.0 M MgCl2 concentration could be well prepared.•Increased addition of gelatin improved the long-term stability of double emulsions.•The particle size of emulsion ...increased due to an osmotic pressure mismatch.•The presence of gelatin could improve the viscoelasticity of emulsion droplets.•Storage temperature of 4 °C was beneficial for maintaining emulsion’s stability.
Water-in-oil-in-water (W/O/W) emulsions could be utilized for fat-reduced food formulation and delivery of bioactive nutrients. However, due to thermodynamic instability, it is difficult to prepare stable double emulsions. The purpose of this study was to improve the stability of W/O/W double emulsions containing 2.0 M MgCl2 by adding porcine gelatin in the inner water phase. The impact of gelatin on the physical stability, microstructure and micro-rheological properties of W/O/W emulsions was investigated. It was found that, when the concentration of porcine gelatin exceeded 4.0 wt%, the stability of emulsions was improved, due to increased viscoelasticity of emulsion droplets. When MgCl2 concentration increased to 2.0 M, the particle size of emulsions increased, due to the osmotic pressure gradient, and the presence of gelatin further increased the droplet size. Confocal microscopy results showed that the presence of gelatin could improve the stability of W/O/W emulsions against coalescence。
A system is proposed to generate vortex electromagnetic (EM) beams in the microwave band, which generates high-order vortex beams at the X-frequency band for the first time. First, the orbital ...angular momentum (OAM)-generating system is designed and the signal model based on the uniform circular array is presented. Subsequently, the mathematical model with array error contributions is established and, comprehensively, numerical simulations are conducted to analyze how amplitude and phase errors affect the radiation field and the EM vortex imaging. The experimental results validate that the proposed system can readily generate vortex beams of high quality, which are in agreement with the simulated results. The work paves the way to applications of OAM-carrying beams as well as a novel information-rich radar paradigm.
Electroencephalogram (EEG) signal-based emotion recognition has attracted wide interests in recent years and has been broadly adopted in medical, affective computing, and other relevant fields. ...However, the majority of the research reported in this field tends to focus on the accuracy of classification whilst neglecting the interpretability of emotion progression. In this paper, we propose a new interpretable emotion recognition approach with the activation mechanism by using machine learning and EEG signals. This paper innovatively proposes the emotional activation curve to demonstrate the activation process of emotions. The algorithm first extracts features from EEG signals and classifies emotions using machine learning techniques, in which different parts of a trial are used to train the proposed model and assess its impact on emotion recognition results. Second, novel activation curves of emotions are constructed based on the classification results, and two emotion coefficients, i.e., the correlation coefficients and entropy coefficients. The activation curve can not only classify emotions but also reveals to a certain extent the emotional activation mechanism. Finally, a weight coefficient is obtained from the two coefficients to improve the accuracy of emotion recognition. To validate the proposed method, experiments have been carried out on the DEAP and SEED dataset. The results support the point that emotions are progressively activated throughout the experiment, and the weighting coefficients based on the correlation coefficient and the entropy coefficient can effectively improve the EEG-based emotion recognition accuracy.
Tiny amounts of a given miRNA (0.1 zmol) can be detected accurately and quantitatively by a real‐time method based on an exponential amplification reaction (see picture). The proposed method has a ...wide dynamic range of more than 10 orders of magnitude, can be carried out within 30 minutes under isothermal conditions, and requires no modified DNA probes. It clearly discriminates miRNA sequences that differ by one base.
Despite their different chemistries, novel energy-storage systems, e.g., Li–air, Li–S, all-solid-state Li batteries, etc., face one critical challenge of forming a conductive and stable interface ...between Li metal and a solid electrolyte. An accurate understanding of the formation mechanism and the exact structure and chemistry of the rarely existing benign interfaces, such as the Li–cubic-Li7–3x Al x La3Zr2O12 (c-LLZO) interface, is crucial for enabling the use of Li metal anodes. Due to spatial confinement and structural and chemical complications, current investigations are largely limited to theoretical calculations. Here, through an in situ formation of Li–c-LLZO interfaces inside an aberration-corrected scanning transmission electron microscope, we successfully reveal the interfacial chemical and structural progression. Upon contact with Li metal, the LLZO surface is reduced, which is accompanied by the simultaneous implantation of Li+, resulting in a tetragonal-like LLZO interphase that stabilizes at an extremely small thickness of around five unit cells. This interphase effectively prevented further interfacial reactions without compromising the ionic conductivity. Although the cubic-to-tetragonal transition is typically undesired during LLZO synthesis, the similar structural change was found to be the likely key to the observed benign interface. These insights provide a new perspective for designing Li–solid electrolyte interfaces that can enable the use of Li metal anodes in next-generation batteries.
Motivated by classical coincidence imaging which has been realized in optical systems, an instantaneous microwave-radar imaging technique is proposed to obtain focused high-resolution images of ...targets without motion limitation. Such a radar coincidence imaging method resolves target scatterers based on measuring the independent waveforms of their echoes, which is quite different from conventional radar imaging techniques where target images are derived depending on time-delay and Doppler analysis. Due to the peculiar features of coincidence imaging, there are two potential advantages of the proposed imaging method over the conventional ones: 1) shortening the imaging time to even a pulse width without resolution deterioration so as to improve the performance of processing noncooperative targets and 2) simplifying the receiver complexity, resulting in a lower cost and platform flexibility in application. The basic principle of radar coincidence imaging is to employ the time-space independent detecting signals, which are produced by a multitransmitter configuration, to make scatterers located at different positions reflect independent waveforms from each other, and then to derive the target image based on the prior knowledge of this detecting signal spatial distribution. By constructing the mathematic model, the necessary conditions of the transmitting waveforms are analyzed for achieving radar coincidence imaging. A parameterized image-reconstruction algorithm is introduced to obtain high resolution for microwave radar systems. The effectiveness of this proposed imaging method is demonstrated via a set of simulations. Furthermore, the impacts of modeling error, noise, and waveform independence on the imaging performance are discussed in the experiments.
Lignin is the only large-volume renewable source of aromatic chemicals. Efficient depolymerization and deoxygenation of lignin while retaining the aromatic functionality are attractive but extremely ...challenging. Here we report the selective production of arenes via direct hydrodeoxygenation of organosolv lignin over a porous Ru/Nb
O
catalyst that enabled the complete removal of the oxygen content from lignin. The conversion of birch lignin to monomer C
-C
hydrocarbons is nearly quantitative based on its monomer content, with a total mass yield of 35.5 wt% and an exceptional arene selectivity of 71 wt%. Inelastic neutron scattering and DFT calculations confirm that the Nb
O
support is catalytically unique compared with other traditional oxide supports, and the disassociation energy of C
-OH bonds in phenolics is significantly reduced upon adsorption on Nb
O
, resulting in its distinct selectivity to arenes. This one-pot process provides a promising approach for improved lignin valorization with general applicability.
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