Mimicking Neuroplasticity in a Hybrid Biopolymer Transistor by Dual Modes Modulation

Neuromorphic computing systems that are capable of parallel information storage and processing with high area and energy efficiencies, offer important opportunities for future storage systems and in‐memory computing. Here, it is shown that a carbon dots/silk protein (CDs/silk) blend can be used as a light‐tunable charge trapping medium to fabricate an electro‐photoactive transistor synapse. The synaptic device can be optically operated in volatile or nonvolatile modes, ensuring concomitant short‐term and long‐term neuroplasticity. The synaptic‐like behaviors are attributed to the photogating effect induced by trapped photogenerated electrons in the hybrid CDs/silk film which is confirmed with atomic force microscopy based electrical techniques. In addition, system‐level pattern recognition capability of the synaptic device is evaluated by a single‐layer perceptron model. The remote optical operation of neuromorphic architecture provides promising building blocks to complete bioinspired photonic computing paradigms.     

Robust Design of Dual‐Phasic Carbon Cathode for Lithium–Oxygen Batteries

Given that the performance of a lithium–oxygen battery (LOB) is determined by the electrochemical reactions occurring on the cathode, the development of advanced cathode nanoarchitectures is of great importance for the realization of high‐energy‐density, reversible LOBs. Herein, a robust cathode design is proposed for LOBs based on a dual‐phasic carbon nanoarchitecture. The cathode is composed of an interwoven network of porous metal–organic framework (MOF) derived carbon (MOF‐C) and conductive carbon nanotubes (CNTs). The dual‐phasic nanoarchitecture incorporates the advantages of both components: MOF‐C provides a large surface area for the oxygen reactions and a large pore volume for Li₂O₂ storage, and CNTs provide facile pathways for electron and O₂ transport as well as additional void spaces for Li₂O₂ accommodation. It is demonstrated that the synergistic nanoarchitecturing of the dual‐phasic MOF‐C/CNT material results in promising electrochemical performance of LOBs, as evidenced by a high discharge capacity of ≈10 050 mAh g^?1 and a stable cycling performance over 75 cycles.     

Rational Engineering of Multilayered Co3O4/ZnO Nanocatalysts through Chemical Transformations from Matryoshka‐Type ZIFs

Hybrid metal oxides with multilayered structures exhibit unique physical and chemical properties, particularly important to heterogeneous catalysis. However, regulations of morphology, spatial location, and shell numbers of the hybrid metal oxides still remain a challenge. Herein, binary Co₃O₄/ZnO nanocages with multilayered structures (up to eight layers) are prepared via chemical transformation from diverse Matryoshka‐type zeolitic imidazolate frameworks (ZIFs) via a straightforward and scalable calcination method. More importantly, the obtained ZIF‐derived metal oxides (ZDMOs) with versatile layer numbers exhibit remarkable catalytic activity for both gas‐phase CO oxidation and CO₂ hydrogenation reactions, which are directly related to the sophisticated shell numbers (i.e., Co₃O₄‐terminated layers or ZnO‐terminated layers). Particularly, in situ reflectance infrared Fourier transform spectroscopy (DRIFTS) results indicate that the promotional effects of the multilayered structures indeed exist in CO₂ hydrogenation, wherein the key reaction intermediates are quite different for five‐layer and six‐layer ZDMOs. For instance, *HCOO is the predominant intermediate over the six‐layer ZDMO; on the contrary, *H₃CO is the crucial species over the five‐layer ZDMO. The ZnO/Co₃O₄ interface should be the active sites for CO₂ hydrogenation to *HCOO and *H₃CO species, which are ultimately converted to the products (CH₄ or methanol). Accordingly, the work here provides a convenient way to facilely engineer multilayered Co₃O₄/ZnO nanocomposites with precisely controlled shell numbers for heterogeneous catalysis applications.     

3D Macroscopic Architectures from Self‐Assembled MXene Hydrogels

Assembly of 2D MXene sheets into a 3D macroscopic architecture is highly desirable to overcome the severe restacking problem of 2D MXene sheets and develop MXene‐based functional materials. However, unlike graphene, 3D MXene macroassembly directly from the individual 2D sheets is hard to achieve for the intrinsic property of MXene. Here a new gelation method is reported to prepare a 3D structured hydrogel from 2D MXene sheets that is assisted by graphene oxide and a suitable reductant. As a supercapacitor electrode, the hydrogel delivers a superb capacitance up to 370 F g^?1 at 5 A g^?1, and more promisingly, demonstrates an exceptionally high rate performance with the capacitance of 165 F g^?1 even at 1000 A g^?1. Moreover, using controllable drying processes, MXene hydrogels are transformed into different monoliths with structures ranging from a loosely organized porous aerogel to a dense solid. As a result, a 3D porous MXene aerogel shows excellent adsorption capacity to simultaneously remove various classes of organic liquids and heavy metal ions while the dense solid has excellent mechanical performance with a high Young's modulus and hardness.     

Engineering a Nanoscale Al‐MOF‐Armored Antigen Carried by a “Trojan Horse”‐Like Platform for Oral Vaccination to Induce Potent and Long‐Lasting Immunity

Vaccination via the oral administration of an antigen faces many challenges, including gastrointestinal (GI) proteolysis and mucosal barriers. To limit GI proteolysis, a biomimetically mineralized aluminum‐based metal–organic framework (Al‐MOF) system that is resistant to ambient temperature and pH and can act synergistically as a delivery vehicle and an adjuvant is synthesized over a model antigen ovalbumin (OVA) to act as armor. To overcome mucosal barriers, a yeast‐derived capsule is used to carry the Al‐MOF‐armored OVA as a “Trojan Horse”‐like transport platform. In vitro experiments reveal that the mineralization of Al‐MOFs forms an armor on OVA that protects against highly acidic and degradative GI conditions. However, the mineralized Al‐MOFs can gradually disintegrate in a phosphate ion‐containing simulated intracellular fluid, slowly releasing their encapsulated OVA. In vivo studies reveal that the “Trojan Horse”‐like transport platform specifically targets intestinal M cells, favoring the transepithelial transport of the Al‐MOF‐armored OVA, followed by subsequent endocytosis in local macrophages, ultimately accumulating in mesenteric lymph nodes, yielding long‐lasting, high‐levels of mucosal S‐IgA and serum IgG antibodies. Such an engineered delivery platform may represent a promising strategy for the oral administration of prophylactic or therapeutic antigens for vaccination.     

Rear‐Passivated Ultrathin Cu(In,Ga)Se2 Films by Al2O3 Nanostructures Using Glancing Angle Deposition Toward Photovoltaic Devices with Enhanced Efficiency

In this work, for the first time, the addition of aluminum oxide nanostructures (Al₂O₃ NSs) grown by glancing angle deposition (GLAD) is investigated on an ultrathin Cu(In,Ga)Se₂ device (400 nm) fabricated using a sequential process, i.e., post‐selenization of the metallic precursor layer. The most striking observation to emerge from this study is the alleviation of phase separation after adding the Al₂O₃ NSs with improved Se diffusion into the non‐uniformed metallic precursor due to the surface roughness resulting from the Al₂O₃ NSs. In addition, the raised Na concentration at the rear surface can be attributed to the increased diffusion of Na ion facilitated by Al₂O₃ NSs. The coverage and thickness of the Al₂O₃ NSs significantly affects the cell performance because of an increase in shunt resistance associated with the formation of Na₂Se_X and phase separation. The passivation effect attributed to the Al₂O₃ NSs is well studied using the bias‐EQE measurement and J–V characteristics under dark and illuminated conditions. With the optimization of the Al₂O₃ NSs, the remarkable enhancement in the cell performance occurs, exhibiting a power conversion efficiency increase from 2.83% to 5.33%, demonstrating a promising method for improving ultrathin Cu(In,Ga)Se₂ devices, and providing significant opportunities for further applications.     

User identification via neural network based language models

Identifying compromised accounts on online social networks that are used for phishing attacks or sending spam messages is still one of the most challenging problems of cyber security. In this research, the authors explore an artificial neural network‐based language model to differentiate the writing styles of different users on short text messages. In doing so, the aim is to be able to identify compromised user accounts. The results obtained indicate that one can learn the language model on one dataset and can generalize it to different datasets to identify users with high accuracy and low false alarm rates without any modification to the language model.     

Modeling and analysis for multilayered complex communication network of satellite navigation system

This study is extended to construct the network model, the node model, and the link model of complex communication network for satellite navigation system (CCN‐SNS) based on the hierarchical architecture. Firstly, a method called snapshots was proposed to describe the dynamic topology for CCN‐SNS; secondly, another method was put forward to model the different nodes of the CCN‐SNS; thirdly, the different links between every two different nodes were modeled. Therefore, based on the OPNET tools, a simulation for the CCN‐SNS, which contains the models that proposed earlier used to analyze the navigation accuracy and network transmission performance, was performed.     

Novel method for transferring access control list rules to synchronize security protection in a locator/identifier separation protocol environment with cross‐segment host mobility

Extended access control lists (ACLs) are used to filter packets for network security. However, in current network frameworks, ACL rules are not transferred simultaneously with devices that move across network segments. The Internet Engineering Task Force proposed the Locator/Identifier Separation Protocol (LISP), which enables routers (xTRs) to configure ACL rules for blocking immobile endpoint identifiers (EIDs). However, when an EID moves from the original xTR to a new xTR, the ACL rules at the original xTR cannot be transferred with the EID. Thus, the new xTR lacks the corresponding ACL rules to effectively block the EID, resulting in security risks. The highlights of this study are as follows. First, a method is proposed for dynamically transferring ACL rules in LISP environments and frameworks. Second, the map‐register and map‐notify protocols were combined to encapsulate and transfer the ACL rules and thus obviate an additional process required to transfer these rules. Third, the experimental results verified that the proposed method can be used to achieve synchronized security protection in an LISP environment involving cross‐segment EID movements.