Organosilicon polymers show great utility as both biocompatible and electrically insulating materials. In this work, thin films of a novel organosilicon polymer are synthesized by initiated chemical vapor deposition utilizing trivinyltrimethylcyclotrisiloxane as a monomer and tert-butyl peroxide as a free-radical-generating initiator. Use of an initiator allows for the formation of polymer films at filament temperatures as low as 250 degrees C, significantly lower than those required to thermally polymerize the monomer species. The mild reaction conditions allow for the retention of all siloxane ring moieties within the resulting polymer. Films deposited at filament temperatures of 600 degrees C or higher exhibit damage to this moiety. The all-dry deposition process generates a highly cross-linked matrix material in which over 95% of the vinyl moieties present on the monomer units have been reacted out to form linear polymerized hydrocarbon chains. While each hydrocarbon backbone chain averages 8.9 monomer units in length, as evaluated by X-ray photoelectron spectroscopy analysis, each monomer unit is involved in three independent chains, resulting in polymer films of such high molecular weight that they are completely insoluble. Kinetic analysis of the deposition process indicates that the film formation rate is limited by the adsorption of reactive species to the deposition substrate, with an apparent activation energy of -23.2 kJ/mol with respect to the substrate temperature. These results are consistent with a surface growth mechanism, ideal for the coating of nonuniform or high aspect ratio substrates.

Aiming at the problems of the difficult extraction of small target feature information, complex background, and variable target scale in unmanned aerial vehicle (UAV) aerial photography images. In this paper, an anchor-free target detection algorithm based on fully convolutional one-stage object detection (FCOS) for UAV aerial photography images is proposed. For the problem of complex backgrounds, the global context module is introduced in the ResNet50 network, which is combined with feature pyramid networks (FPN) as the backbone feature extraction network to enhance the feature representation of targets in complex backgrounds. To address the problem of the difficult detection of small targets, an adaptive feature balancing sub-network is designed to filter the invalid information generated at all levels of feature fusion, strengthen multi-layer features, and improve the recognition capability of the model for small targets. To address the problem of variable target scales, complete intersection over union (CIOU) Loss is used to optimize the regression loss and strengthen the model’s ability to locate multi-scale targets. The algorithm of this paper is compared quantitatively and qualitatively on the VisDrone dataset. The experiments show that the proposed algorithm improves 4.96% on average precision (AP) compared with the baseline algorithm FCOS, and the detection speed is 35 frames per second (FPS), confirming that the algorithm has satisfactory detection performance, real-time inference speed, and has effectively improved the problem of missed detection and false detection of targets in UAV aerial images.

Density functional theory calculations have been carried out to investigate 3d, Pd and Pt transition metal (TM) atoms exohedrally and endohedrally doped B 80 fullerene. We find that the most preferred doping site of the TM atom gradually moves from the outer surface ( TM = Sc ), to the inner surface ( TM = Ti and V ) and the center ( TM = Cr , Mn , Fe and Zn ), then to the outer surface ( TM = Co , Ni , Cu , Pd , and Pt ) again with the TM atom varying from Sc to Pt . From the formation energy calculations, we find that doping TM atom can further improve the stability of B 80 fullerene. The magnetic moments of doped V , Cr , Mn , Fe , Co and Ni atoms are reduced from their free-atom values and other TM atoms are completely quenched. Charge transfer and hybridization between 4s and 3d states of TM and 2s and 2p states of B were observed. The energy gaps of TM @ B 80 are usually smaller than that of the pure B 80. Endohedrally doped B 80 fullerene with two Mn and two Fe atoms were also considered, respectively. It is found that the antiferromagnetic (AFM) state is more energetically favorable than the ferromagnetic (FM) state for Mn 2- and Fe 2@ B 80. The Mn and Fe atoms carry the residual magnetic moments of ~ 3 μB and 2 μB in the AFM states.

In this work, a commercial foldable display of 8.0-inch 2K AMOLED(Active Matrix Organic Light-emitting Diode) was developed for foldable smart phones. By considering commercial requirements for a brand new product, fundamental performances are introduced. By new design concepts, display and touch performances are guaranteed, while the foldable reliabilities are also achieved to a commercial goal. Not only how to improve the bending abilities, but also the mechanical abilities of foldable display module are discussed. In bending performance, the endurance of dynamic folding and static folding are treated by different ways. The materials and layer stacks optimization are discussed. The root causes of the deformation in foldable display are analyzed. Solutions for the out-folding display is suggested.

No abstract