| 1 | High-speed optical secure communication with an external noise source and an internal time-delayed feedback loop显示文摘We propose and experimentally demonstrate a novel physical layer encryption scheme for high-speed optical communication. A 10 Gb/s on-off keying signal is secretly transmitted over 100 km standard single-mode fiber.The intensity-modulated message is secured by the encryption mechanism, which is composed of an external noise source and an internal time-delayed feedback loop. The external noise serves as an entropy source with sufficient randomness. The feedback loop structure in the transmitter introduces a time-domain encryption key space, and a corresponding open-loop configuration at the receiver side is used for synchronization and decryption.Experiment results show the effectiveness of the proposed scheme. For a legitimate terminal, bit error rate below10-8 can be obtained. Decryption degradations with the mismatch of different hardware parameters are researched. The time delay in the feedback loop provides a sensitive encryption key. For other hardware parameters,the system is robust enough for synchronization. Meanwhile, the time-delay signature of the loop is able to be well concealed by the external noise. Moreover, the proposed scheme can support density wavelength division multiplexing transmission with a relatively simple structure. This work also provides a new concept to establish optical secure communication by combining a time-delayed feedback chaotic system and random noise. | YUDI FU MENGFAN CHENG XINGXING JIANG QUAN YU LINBOJIE HUANG LEI DENG DEMING LIU | 2019 | Photonics Research2019，7，11： | 2 |
| 3 | Adhesive and Self-Healing Polyurethanes with Tunable Multifunctionality显示文摘Many polyurethanes(PUs)are blood-contacting materials due to their good mechanical properties,fatigue resistance,cytocompatibility,biosafety,and relatively good hemocompatibility.Further functionalization of the PUs using chemical synthetic methods is especially attractive for expanding their applications.Herein,a series of catechol functionalized PU(CPU-PTMEG)elastomers containing variable molecular weight of polytetramethylene ether glycol(PTMEG)soft segment are reported by stepwise polymerization and further introduction of catechol.Tailoring the molecular weight of PTMEG fragment enables a regulable catechol content,mobility of the chain segment,hydrogen bond and microphase separation of the C-PUPTMEG elastomers,thus offering tunability of mechanical strength(such as breaking strength from 1.3 MPa to 5.7 MPa),adhesion,self-healing eficiency(from 14.9%to 96.7%within 2 hours),anticoagulant,antioxidation,anti-inflammatory properties and cellular growth behavior.As cardiovascular stent coatings,the C-PU-PTMEGs demonstrate enough flexibility to withstand deformation during the balloon dilation procedure.Of special importance is that the C-PU-PTMEG-coated surfaces show the ability to rapidly scavenge free radicals to maintain normal growth of endothelial cells,inhibit smooth muscle cell proliferation,mediate inflammatory response,and reduce thrombus formation.With the universality of surface adhesion and tunable multifunctionality,these novel C-PU-PTMEG elastomers should find potential usage in artificial heart valves and surface engineering of stents. | Lei Zhou Lu Zhang Peichuang Li Manfred F.Maitz Kebing Wang Tengda Shang Sheng Dai Yudie Fu Yuancong Zhao Zhilu Yang Jin Wang Xin Li | 2023 | Research2023，，1： | 0 |
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