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On account of its superior insulating performance and low global warming potential (GWP), C4F7N has been the focus of replacing SF6. Based on density functional theory, the adsorption mechanism and electrical characteristics of GeSe monolayer towards C4F7N decomposition species (COF2, CF4, CF3CN and C2F5CN) are explored to investigate the feasibility of GeSe gas sensors. Compared with other decomposition products, GeSe monolayers are more capable of capturing for C2F5CN, as evidenced by the smallest band gap (0.781 eV) and the highest adsorption energy (−0.427 eV). The adsorption behaviors lead to a larger GeSe band gap and thus a decrease in the conductivity of the adsorption system. The adsorption types of GeSe for four gases are all physical adsorption and can have good desorption properties at room temperature (298 K) with the adsorption capabilities: C2F5CN>CF3CN>COF2>CF4. Theoretically, GeSe monolayers can be used to create a novel gas sensor for and industrial application, which can be utilized to monitor and diagnose high-voltage insulated equipment in real time. [ABSTRACT FROM AUTHOR]

Multifunctional flexible electronics have been a hot spot in scientific research and technology development. From the view of practical application, high-performance flexible heating devices with the capability to respond to commands are an urgent need for thermal management. Herein, we propose a strategy for multifunctional integration by assembling two pieces of laser-scribed Nomex paper, thus enabling the combination of heating and sensing modules. On account of the good electrothermal and piezoresistive properties of laser-induced graphene, the device can generate high steady-state temperature with a low voltage excitation and recognize valid commands from users finger to switch between operating states. Besides, the fast and efficient fabrication method entirely based on direct laser writing technology is another unique advantage. [ABSTRACT FROM AUTHOR]

Real-time and accurate detection of H2S has been an urgent problem in industry and human health. In view of practical problems of the existing nano sensors such as poor selectivity, low sensitivity, strong or weak adsorption capacity, H2S sensors based on metal oxide nanoparticles (XO, X = Cu, Zn, Ni) doped GeSe monolayer are proposed. Compared with pure system, the improvement of the adsorption distance of doped systems proves the obvious interaction between the activated atoms and H2S. The excellent sensitivity ensures the detection effect of H2S at low concentration. The ideal adsorption energy makes doped systems have attractive adsorption and desorption properties. In addition, the excellent water resistance, high thermal stability and fascinating selectivity to H2S of doped systems verify the feasibility in practical application. This study lays a theoretical foundation for the development of new generation of wearable gas sensor for health and industrial monitoring. [ABSTRACT FROM AUTHOR]

Based on micro-nano sensing technology, the structural and electronic characteristics of metal-doped boron nitride monolayer are investigated by first principles. The existing nano sensors have practical problems, such as no selectivity, too strong adsorption capacity to be recycled, too weak adsorption capacity to obtain sufficient response. We explore the use of a highly sensitive recyclable nano sensor that is best suited for sensing function. Gas adsorption properties for the toxic decomposition gases of C4F7 N are further developed. We select the N-vacancy with the highest binding energies, which are −6.34 eV when doped by Co atom. The strong interaction and suitable adsorption energy between the activated atoms of adsorbent and gases prove their unique adsorption properties. Since no new chemical bonds are formed, it is obvious that systems are in the form of physical adsorption, which proves their ideal desorption properties. In addition, the conductivity increases to different degrees due to the redistribution of electrons, which proves excellent selectivity. Hence, we propose the use of Co-BNN nanomaterial for the detection of C4F7N toxic decomposition gases. Results would serve as instructive reference for the investigation of resistive gas-sensitive sensors. [ABSTRACT FROM AUTHOR]

We have studied the effects of gamma radiation on flexible superconducting microstrip transmission line structures, to explore their suitability for use in harsh environments where they may be subjected to radiation. In this work, we used two conductor variants: one with only Nb and another with a conductor stack of Al/Nb/Al. Spin-on polyimide HD-4110 was used as the dielectric substrate and both the variants were encapsulated with a layer of HD-4110 to increase the robustness of the structure by protecting the superconducting trace from potential mechanical damage. The resonators were irradiated at room temperature in a vacuum sealed chamber at a pressure of 1E-6 Torr using cobalt-60 as a source of gamma radiation. Samples were exposed to doses up to 60.8 Mrad (608 kGy). Quality factors of the resonators were extracted in the frequency range from 2 to 20 GHz, at various cryogenic temperatures between 1.2 K and 4.2 K, using a closed-cycle cryostat. We observed a small increase in microwave loss for higher temperature ranges, which points to a small change in the superconducting properties of the conductors. The results of this work show that low mass, flexible superconducting cables may be suitable alternatives to bulky coaxial cables for signal transmission at cryogenic temperatures in extreme (radiation) environments. [ABSTRACT FROM AUTHOR]

Real-time monitoring of SF6 status is of exceptional importance to ensure stable operation of the power system, to promptly diagnose whether an insulation failure has occurred and to assess the severity. Considering the excellent physicochemical properties and insulation defects of hexagonal boron nitride, the strategy of surface modification, namely, hydrogenation, fluorination, and combinations of the two ways, is proposed to improve its chemical activity, and the gas-sensing potential of the most effective one is investigated using density functional theory. The typical adsorption models of SF6 decomposition component gases on the surface of F-BN-H are constructed, and the most stable adsorption structures with their density of states, molecular orbitals, and sensing responses are analyzed. The results show that F-BN-H has good sensitivity to decomposition components of SF6. To be specific, SO2 and SOF2 have good adsorption properties, prominent charge transfer, and distinct change in electronic properties. The response of gas adsorption can be detected timely by the change in conductivity, and, additionally, the adsorbent has fast desorption capacity at room temperature. These results indicate that the F-BN-H-based gas sensor is a qualified potential candidate with dependable application and recoverability for detecting SF6 decomposition in high-voltage insulated equipment. [ABSTRACT FROM AUTHOR]

We present the design, fabrication procedure, and measurement results of Nb superconducting microstrip transmission line resonators fabricated using thin-film polyimide HD-4110, including both nonembedded and embedded versions. These resonators were used to characterize the microwave dielectric loss tangent of 20  $\mu$m thick polyimide HD-4110 at deep cryogenic temperatures. We observed high-quality factors (Q) up to 21 040 at 1.2 K in the frequency range of 2–21 GHz for nonembedded resonators, indicating that the dielectric loss tangent can be less than 5 $\times$10−5. Embedded resonators with an additional 20 $\mu$m thick encapsulation layer also exhibited Q values as high as $\sim 19$ 200. Dielectric and conductor (quasiparticle) loss have been compared between the two types of resonators. This study provides information applicable to the design of future high-density, flexible, multilayer superconducting cables, which are of great interest for potential applications in cryogenic electronics systems, including quantum computers. [ABSTRACT FROM PUBLISHER]