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A lossy-mode resonance (LMR) refractive index (RI) sensor with a few layer transition metal dichalcogenides (TMDs) is proposed. Contrasting with traditional surface plasmon resonance (SPR) sensors, the LMR sensor can support both transverse magnetic (TM) and transverse electric (TE) polarizations, while the traditional SPR sensors can only operate for TM polarization. Through theoretical calculation and simulation, we find that the proposed LMR sensor can realize higher sensitive and narrower full width half maximum (FWHM), and the most attractive character is figure-of-merit (FOM) with 1582 RIU−1, which is a significant improvement compared to the existing LMR sensors and is even 40% higher than the best graphene-based SPR sensors. We trust that the proposed LMR sensor can be extensively applied in optical sensing technology, chemical biomolecular detection, and so on. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • SnS 2 /ZIF-8 derived porous flower-like SnO 2 /ZnO heterostructures were obtained. • New self-assembled SnS 2 flower-like microstructures were used as templates. • SnO 2 /ZnO composites exhibit high sensitivity and selectivity to TEA at 200 °C. • Tunable morphology and n–n heterojunctions play a key role for gas sensing property. • The method can be used for obtaining other heterostructures with novel shapes. Abstract SnO 2 -based flower-like sensitive materials derived from the self-assembled SnS 2 microstructures with more active areas and less agglomeration represent an alternative option for new generation of gas sensors. Meanwhile, the introduction of ZIF-8 for semiconductor surface functionalization is expected to get multi-functional hybrid materials with synergistic effects of individual components. In the present work, SnS 2 /ZIF-8 derived porous flower-like SnO 2 /ZnO heterostructures have been synthesized by a facile template method and the subsequent heat-treatment process. Beside the uniform morphology with tunable composition and size distribution, the attractive findings are focused on the enhanced triethylamine (TEA) gas-sensing properties of the obtained composites. SnO 2 /ZnO heterostructures show an obvious improvement in TEA gas sensing performance at the operating temperature of 200 °C, giving a response of about 17.7–50 ppm TEA, which was about 2.2 times higher than that of the sensors based on pure SnO 2. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cubic-like In 2 O 3 /α-Fe 2 O 3 composites assembled with porous nanoplates are obtained. • The introduction of Fe3+ component plays a vital role for morphological evolution. • In 2 O 3 /α-Fe 2 O 3 composites display superior TEA gas-sensing behavior at 170 °C. • In/Fe-2 shows the highest response and excellent cycling and long-term stability. • Sensing mechanism mainly depends on the unique microstructure and heterojunction. Cubic-like In 2 O 3 /α-Fe 2 O 3 heterostructures assembled with 2D porous nanoplates have been prepared by solvothermal method and subsequent calcination process. The introduction of Fe3+ component plays an important role for the morphological evolution of In 2 O 3 -based samples with unique crystal nucleation and growth mechanism. Compared with flower-like In 2 O 3 self-assemblies composed of tower-like structural units, In 2 O 3 /α-Fe 2 O 3 composites can display superior trimethylamine (TEA) gas-sensing behavior. For example, the optimal working temperature is reduced from 250 to 170 °C, and the response value of In/Fe-2 materials is 375.43, which is about 6.23 times than that of In 2 O 3 sensors. The enhanced gas-sensing properties are mainly attributed to large specific surface area (234.4 m2/g), the effective In 2 O 3 -α-Fe 2 O 3 heterojunctions, unique surface/interface effects, and tunable electron transmission mechanism. [ABSTRACT FROM AUTHOR]

Morphology-controlled porous α-Fe 2 O 3 /SnO 2 nanorods with uniform surface heterostructures have been fabricated by a facile surface modification of rod-like α-Fe 2 O 3 nanomaterials by changing the adding amount of Sn composition, displaying the excellent selectivity and sensitivity of gas-sensing to acetone. The introduction of SnO 2 nanoparticles had the great effects on tuning the crystal size, crystallinity, and surface status, as well as the structural stability and phase distribution of α-Fe 2 O 3 /SnO 2 nanorods. Compared to pure α-Fe 2 O 3 , α-Fe 2 O 3 /SnO 2 heterostructures can exhibit the optimal gas-sensing behavior with the sensitivity up to 53.1 and the response and recovery times decreasing to 9 and 2.5 s at the operating temperature of 260 °C, respectively. The enhanced gas-sensing performance can be mainly attributed to the combination of uniform porous structures, narrow size-distribution, large specific surface area, and heterostructures of the interface between α-Fe 2 O 3 and SnO 2 . [ABSTRACT FROM AUTHOR]

With the ever increasing deployment density of Wireless Local Area Networks (WLANs), more and more access points (APs) are deployed within users' vicinity. The effective management of these APs to optimize the users' throughput becomes an important challenge in high-density deployment environments. In this paper, we propose a user-centric network management framework to optimize users' throughput taking into consideration both the network conditions sensed by users and their access priorities. The proposed framework is built around an information pipeline that facilitates the sharing of the information needed for optimal management of communication resources. Theoretical analysis and extensive simulations are presented on two major management activities: AP association and channel selection, and demonstrate that the proposed user-centric network management framework significantly outperforms traditional network management framework in the high-density deployment environment. [ABSTRACT FROM PUBLISHER]

• Tunable C-N/SnO 2 /Co 3 O 4 microspheres were prepared via an electrospinning route. • The introduction of ZIF-67 affects the composition and gas-sensing property. • C-N/SnO 2 /Co 3 O 4 microspheres show excellent gas-sensing performance to TEA. • The threshold limit of response can be observed as the exposure to 5 ppm TEA. • Synergistic combination of p-n heterojunction and C-N components was discussed. Composition-tunable C-N/SnO 2 /Co 3 O 4 microspheres with available gas-sensing behavior were successfully fabricated via a facile electrospinning technology, mainly achieved by different adding amounts of ZIF-67. It is found that both the introduction of C-N components and the formation of p-n heterojunction can effectively accelerate electron transmission and enhance the gas sensitivity properties of the material toward trimethylamine (TEA). The highest response of C-N/SnO 2 /Co 3 O 4 microspheres can reach up to approximately 154.3, calculated to be 9 times for 50 ppm triethylamine molecules at a temperature of 360 °C than that of C-N/SnO 2 microspheres. Moreover, the threshold limit value of gas response can be observed as the exposure to even a concentration of merely 5 ppm TEA, indicating their potential application on detecting TEA released during the decay process of prawn in the low concentration region. [ABSTRACT FROM AUTHOR]