Reticulate Dual‐Nanowire Aerogel for Multifunctional Applications: a High‐Performance Strain Sensor and a High Areal Capacity Rechargeable Anode

Nanowire aerogels (NWAs) are highly versatile and used in many applications. However, most synthesized NWAs are composed of single components that may produce unsatisfactory aggregated performance in mechanical strength, conductivity, and electrochemistry. To address this issue, a reticulate dual‐nanowire aerogel (rDNWA) composed of FeS₂ nanowires and carbon nanotubes (CNTs) via a simple solvothermal method is synthesized. The rDNWA possesses excellent compressibility (modulus of 1.32 MPa), good conductivity (0.65 S cm^?1), and high porosity (>98%). It can be applied as a high‐performance strain sensor with good sensitivity (Gauge Factor = 1.69) and enhanced stability. It can be densified to yield a high areal capacity of 10.0 mAh cm^?2 and a high mass loading of 14.4 mg cm^?2 after 100 cycles. As a freestanding anode for lithium ion battery (LIB), it exhibits a high specific mass capacity of 1031 mAh g^?1 after 100 cycles at a current density of 100 mA g^?1 and retains it to 729 mAh g^?1 at a current density of 500 mA g^?1 after 400 cycles. The outstanding overall performance of the hybrid aerogel is derived from the synergistic effect of intertwined CNTs and FeS₂ nanowires and can be extended to fabricate NWAs with novel multifunctional capabilities.     

Zr‐Doped Indium Oxide (IZRO) Transparent Electrodes for Perovskite‐Based Tandem Solar Cells

Parasitic absorption in transparent electrodes is one of the main roadblocks to enabling power conversion efficiencies (PCEs) for perovskite‐based tandem solar cells beyond 30%. To reduce such losses and maximize light coupling, the broadband transparency of such electrodes should be improved, especially at the front of the device. Here, the excellent properties of Zr‐doped indium oxide (IZRO) transparent electrodes for such applications, with improved near‐infrared (NIR) response, compared to conventional tin‐doped indium oxide (ITO) electrodes, are shown. Optimized IZRO films feature a very high electron mobility (up to ≈77 cm² V^?1 s^?1), enabling highly infrared transparent films with a very low sheet resistance (≈18 Ω □^?1 for annealed 100 nm films). For devices, this translates in a parasitic absorption of only ≈5% for IZRO within the solar spectrum (250–2500 nm range), to be compared with ≈10% for commercial ITO. Fundamentally, it is found that the high conductivity of annealed IZRO films is directly linked to promoted crystallinity of the indium oxide (In₂O₃) films due to Zr‐doping. Overall, on a four‐terminal perovskite/silicon tandem device level, an absolute 3.5 mA cm^?2 short‐circuit current improvement in silicon bottom cells is obtained by replacing commercial ITO electrodes with IZRO, resulting in improving the PCE from 23.3% to 26.2%.     

Cryptanalysis and improvement of ‘a robust smart‐card‐based remote user password authentication scheme’

With the use of smart card in user authentication mechanisms, the concept of two‐factor authentication came into existence. This was a forward move towards more secure and reliable user authentication systems. It elevated the security level by requiring a user to possess something in addition to know something. In 2010, Sood et al. and Song independently examined a smart‐card‐based authentication scheme proposed by Xu et al. They showed that in the scheme of Xu et al., an internal user of the system can turn hostile to impersonate other users of the system. Both of them also proposed schemes to improve the scheme of Xu et al. Recently, Chen et al. identified some security problems in the improved schemes proposed by Sood et al. and Song. To fix these problems, Chen et al. presented another scheme, which they claimed to provide mutual authentication and withstand lost smart card attack. Undoubtedly, in their scheme, a user can also verify the legitimacy of server, but we find that the scheme fails to resist impersonation attacks and privileged insider attack. We also show that the scheme does not provide important features such as user anonymity, confidentiality to air messages, and revocation of lost/stolen smart card. Besides, the scheme defies the very purpose of two‐factor security. Furthermore, an attacker can guess a user's password from his or her lost/stolen smart card. To meet these challenges, we propose a user authentication method with user anonymity. We show through analysis and comparison that the proposed scheme exhibits enhanced efficiency in contrast to related schemes, including the scheme of Chen et al. Copyright © 2013 John Wiley & Sons, Ltd.     

Evaluation of process parameter space of bulk FinFETs using 3D TCAD

Using full 3D TCAD, an evaluation of process parameter space of bulk FinFET is presented from the point of view of DRAM, SRAM and I/O applications. Process and device simulations are performed with varying uniform fin doping, anti-punch implant dose and energy, fin width, fin height and gate oxide thickness. Bulk FinFET architecture with anti-punch implant is introduced beneath the channel region to reduce the punch-through and junction leakage. For 30 nm bulk FinFET, anti-punch implant with low energy of 15 to 25 keV and dose of 5.0 × 10¹³ to 1.0 × 10¹⁴ cm⁻² is beneficial to effectively suppress the punch-through leakage with reduced GIDL and short channel effects. Our simulations show that bulk FinFETs are approximately independent of back bias effect. With identical fin geometry, bulk FinFETs with anti-punch implant show same I_ON-I_OFF behavior and approximately equal short channel effects like SOI FinFETs.     

Ultra-Robust Flexible Electronics by Laser-Driven Polymer-Nanomaterials Integration

Polyethylene terephthalate (PET) is the most widely used polymer in the world. For the first time, the laser-driven integration of aluminum nanoparticles (Al NPs) into PET to realize a laser-induced graphene/Al NPs/polymer composite, which demonstrates excellent toughness and high electrical conductivity with the formation of aluminum carbide into the polymer is shown. The conductive structures show an impressive mechanical resistance against >10000 bending cycles, projectile impact, hammering, abrasion, and structural and chemical stability when in contact with different solvents (ethanol, water, and aqueous electrolytes). Devices including thermal heaters, carbon electrodes for energy storage, electrochemical and bending sensors show this technology's practical application for ultra-robust polymer electronics. This laser-based technology can be extended to integrating other nanomaterials and create hybrid graphene-based structures with excellent properties in a wide range of flexible electronics’ applications.     

3D Printed Enzyme-Functionalized Scaffold Facilitates Diabetic Bone Regeneration

Patients with diabetes mellitus (DM) suffer from a high risk of fractures and poor bone healing ability. Surprisingly, no effective therapy is available to treat diabetic bone defect in clinic. Here, a 3D printed enzyme-functionalized scaffold with multiple bioactivities including osteogenesis, angiogenesis, and anti-inflammation in diabetic conditions is proposed. The as-prepared multifunctional scaffold is constituted with alginate, glucose oxidase (GOx), and catalase-assisted biomineralized calcium phosphate nanosheets (CaP@CAT NSs). The GOx inside scaffolds can alleviate the hyperglycemia environment by catalyzing glucose and oxygen into gluconic acid and hydrogen peroxide (H₂O₂). Both the generated H₂O₂ as well as the overproduced H₂O₂ in DM can be scavenged by CaP@CAT NSs, while the initiated hypoxic microenvironment stimulates neovascularization. Moreover, the incorporation of CaP@CAT NSs not only enhance the mechanical property of the scaffolds, but also facilitate bone regeneration by the degraded Ca²⁺ and PO₄³⁻ ions. The remarkable in vitro and in vivo outcomes demonstrate that enzymes functionalized scaffolds can be an effective strategy for enhancing bone tissue regeneration in diabetic conditions, underpinning the potential of multifunctional scaffolds for diabetic bone regeneration.     

Secure sensors data acquisition and communication protection in eHealthcare: Review on the state of the art

Recent advances in hardware technology have led to the development of low cost, power efficient and more feature rich devices that are amongst the most critical parts of communication networks. These devices or sensors can now sense data with more accuracy, process it by themselves and send it to the neighboring node or the sink node. However, robust and reliable security mechanisms are not yet properly implemented on these sensors due to their limited energy and computation power. Sensors also play a very important role in eHealthcare systems where ubiquitous patient monitoring is performed. As data is generated from the sensor nodes, reliable, secure and attack-resistant data acquisition and transmission is important for an efficient eHealthcare systems. This survey focuses on security issues of sensors data acquisition and transmission protocols, describing their main security features and comparing them in the context of a secure eHealthcare system. A taxonomy of open issues and future challenges is also discussed with respect to specific security metrics described in the paper.     

New Strategy for Polysulfide Protection Based on Atomic Layer Deposition of TiO2 onto Ferroelectric‐Encapsulated Cathode: Toward Ultrastable Free‐Standing Room Temperature Sodium–Sulfur Batteries

The room temperature (RT) sodium–sulfur batteries (Na–S) hold great promise for practical applications including energy storage and conversion due to high energy density, long lifespan, and low cost, as well based on the abundant reserves of both sodium metal and sulfur. Herein, freestanding (C/S/BaTiO₃)@TiO₂ (CSB@TiO₂) electrode with only ≈3 wt% of BaTiO₃ additive and ≈4 nm thickness of amorphous TiO₂ atomic layer deposition protective layer is rational designed, and first used for RT Na–S batteries. Results show that such cathode material exhibits high rate capability and excellent durability compared with pure C/S and C/S/BaTiO₃ electrodes. Notably, this CSB@TiO₂ electrode performs a discharge capacity of 524.8 and 382 mA h g^?1 after 1400 cycles at 1 A g^?1 and 3000 cycles at 2 A g^?1, respectively. Such superior electrochemical performance is mainly attributed from the “BaTiO₃‐C‐TiO₂” synergetic structure within the matrix, which enables effectively inhibiting the shuttle effect, restraining the volumetric variation and stabilizing the ionic transport interface.