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Recent advancements in network and multimedia technologies have facilitated the distribution and sharing of digital videos over the Internet. These long videos contain very complex contents. Additionally, it is very challenging to use as few frames as possible to cover the video contents without missing too much information. There are at least two ways to describe these complex videos contents with minimal frames: the keyframes extracted from the video or the video summary. The former lays stress on covering the whole video contents as much as possible. The latter emphasizes covering the video contents of interest. As a consequence, keyframes are widely used in many areas such as video segmentation and object tracking. In this paper, we propose a keyframe extraction method based on multiple features via a novel combinatorial optimization algorithm. The key frame extraction is modeled as a combinatorial optimization problem. A fast dynamic programming algorithm based on a forward non-overlapping transfer matrix in polynomial time and a 0-1 integer linear programming algorithm based on an overlapping matrix is proposed to solve our maximization problem. In order to quantitatively evaluate our approach, a long video dataset named 'Animal world' is self-constructed, and the segmentation evaluation criterions are introduced. A good result is achieved on 'Animal world' dataset and a public available Keyframe-Sydney KFSYD dataset [1]. [ABSTRACT FROM AUTHOR]

The practical application of aqueous Zn‐ion batteries is still greatly hindered by the unstable Zn anode with severe Zn dendrites growth and side reactions. As it is accessible and economical, the exploitation of electrolyte additives is one of the most promising strategies to stabilize the Zn electrode/electrolyte interface. Herein, the penta‐potassium triphosphate (KTPP) as a novel trifunctional electrolyte additive is introduced to tune the electrode/electrolyte interface. First, the KTPP additive can induce an ion‐conducting and mechanically robust solid electrolyte interphase film to stabilize the Zn anode. Second, the KTPP can complex with Zn2+ ions to reconstitute the dissolution sheath structure of the Zn2+ ion. Finally, the K+ cations in KTPP adsorb on the tips of the Zn anode surface as a shielding film to regulate Zn2+ ion flux. As a result, Zn//Zn symmetric cells can achieve significantly prolonged cycling stability (e.g., from 1077 to 3800 h at 1 mA cm−2/1 mAh cm−2, from 256 to 2500 h at 2 mA cm−2/2 mAh cm−2), and ultrahigh cumulative capacity of 6400/7200 mAh cm−2 at high current density (40/20 mA cm−2). A four‐layer Zn–MnO2 pouch full cell with a high capacity of 9 mAh can be constructed, showing impressive practical application potential. [ABSTRACT FROM AUTHOR]

The Zimm plot has been widely used to characterize the molecular dimensions of polymers from small‐angle scattering experiments, where the reciprocal intensity is analyzed as a function of the square of the magnitude of the scattering wavevector Q. This work explores the benefits of analyzing the reciprocal scattering intensity from deformed polymers, extending the original Zimm plot to anisotropic materials. In the small‐angle limit, a tensorial extension of the Guinier law is found for the gyration tensor and the reciprocal single‐chain structure factor. In the high‐Q limit, application of the spherical harmonic expansion technique to the reciprocal structure factor permits direct model‐independent analysis of spatially dependent molecular deformation of polymers. Additionally, the contributions from high‐order spherical harmonics become insignificant in the reciprocal‐intensity representation. The proposed generalized Zimm plot approach is demonstrated computationally with the affine deformation model and the Rouse model, and experimentally with small‐angle neutron scattering measurements of deformed polystyrene melts. [ABSTRACT FROM AUTHOR]

Fast deformation of entangled melts is known to cause chain stretching due to affinelike straining of the entanglement network. Since the chain deformation may also result in perturbations of covalent bond angles and bond length, there are always possible enthalpic effects. In this study, we first subject polystyrene and PMMA of different molecular weights to either uniaxial melt extension or planar extension and subsequently impose rapid thermal quenching to preserve the chain deformation. Then, such pre-melt-deformed samples are annealed at various temperatures below the glass transition temperature Tg. During annealing, these samples can undergo appreciable contraction on a time scale much shorter than the alpha relaxation time. Significant retractive stress is observed when such contracting samples are held fixed during the annealing. The stress level can be nearly as high as the Cauchy stress produced during melt stretching. These observations not only allowed us to investigate glassy chain dynamics as well as the molecular nature of mechanical stress but may also suggest that pre-melt-stretched polymers can cause segmental mobilization in the glassy state. The available evidence indicates that the retractive stress is enthalpic in origin, associated with the conformational distortion at the bond level produced by melt stretching. [ABSTRACT FROM AUTHOR]