Incorporation of new functional components into a three-dimensional graphene (3DG) framework improves the performance of supercapacitors based on 3DG as electrodes by tailoring the framework’s structure and properties. In this work, graphene quantum dots (GQDs) were incorporated into 3DG via one-step hydrothermal treatment of GQDs and graphene oxide (GO). By simply adjusting the GQDs/GO feeding ratio by weight, various GQDs/3DG composites were formed. The maximum feeding ratio was 80%, and the prepared composites possessed saturated GQDs loading on the 3DG framework, whereas composites obtained with a GQDs/GO feeding ratio of 40% as electrodes exhibited optimal specific capacitance of 242 F·g⁻¹ for supercapacitors, an increase of 22% compared with that of pure 3DG electrodes (198 F·g⁻¹). This improved performance was mainly due to better electrical conductivity and larger surface area for GQDs/3DG composites with moderate GQDs content. The fabricated GQDs/3DG composites as electrodes for supercapacitors revealed high electrochemical stability. Their capacitance kept 93% of the initial value after 10,000 charge-discharge cycles.

The development of high-performance acetone gas sensor is of great significance for environmental protection and personal safety. SnO₂ has been intensively applied in chemical sensing areas, because of its low cost, high mobility of electrons, and good chemical stability. Herein, we incorporated nitrogen atoms into the SnO₂ nanostructure by simple solvothermal and subsequent calcination to improve gas sensing property for acetone. The crystallization, morphology, element composition, and microstructure of as-prepared products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Electron paramagnetic resonance (EPR), Raman spectroscopy, UV–visible diffuse reflectance spectroscopy (UV–vis DRS), and the Brunauer–Emmett–Teller (BET) method. It has been found that N-incorporating resulted in decreased crystallite size, reduced band-gap width, increased surface oxygen vacancies, enlarged surface area, and narrowed pore size distribution. When evaluated as gas sensor, nitrogen-incorporated SnO₂ nanostructure exhibited excellent sensitivity for acetone gas at the optimal operating temperature of 300 °C with high sensor response (R_air/R_gas − 1 = 357) and low limit of detection (7 ppb). The nitrogen-incorporated SnO₂ gas sensor shows a good selectivity to acetone in the interfering gases of benzene, toluene, ethylbenzene, hydrogen, and methane. Furthermore, the possible gas-sensing mechanism of N-incorporated SnO₂ toward acetone has been carefully discussed.

In this work, mesoporous nickel oxide (NiO) hierarchical nanostructures were synthesized by a facile approach by hydrothermal reaction and subsequent calcination. The phase structure, microstructure, element composition, surface area, and pore size distribution of the as-prepared products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and the Brunauer–Emmett–Teller (BET) technique. The precursor of Ni₃(NO₃)₂(OH)₄ nanosheet, Ni₃(NO₃)₂(OH)₄ microsphere, and Ni(HCO₃)₂ sub-microsphere was obtained by hydrothermal reaction at 160 °C for 4 h when the ratio of Ni²⁺/HMT (hexamethylenetetramine) was 2:1, 1:2, and 1:3, respectively. After calcination at 400 °C for 2 h, the precursors were completely transformed to mesoporous NiO hierarchical nanosheet, microsphere, and sub-microsphere. When evaluated as additives of the thermal decomposition of ammonium perchlorate (AP), these NiO nanostructures significantly reduce the decomposition temperature of AP, showing obvious catalytic activity. In particular, NiO sub-microsphere have the best catalytic role, which can reduce the high temperature decomposition (HTD) and low temperature decomposition (LTD) temperature by 75.2 and 19.1 °C, respectively. The synthetic approach can easily control the morphology and pore structure of the NiO nanostructures by adjusting the ratio of Ni²⁺/HMT in the reactants and subsequent calcination, which avoids using expensive templates or surfactant and could be intended to prepare other transition metal oxide.

In this paper, to explore the current situation and future trend of the healthy development of China’s sports industry, the health evaluation index system of the sports industry was established by deconstructing the health dimension of the sports industry. The health evaluation model of the sports industry was constructed by using the entropy method and the multi-objective linear weighting method. The model was used to empirically analyze the characteristics and laws of the health of China’s sports industry from 2008 to 2017 and predict the health status of China’s sports industry in the next 10 years with the combination with the GM (1.1) model. The results show that the potential health degree of China’s sports industry exhibits a fluctuating growth trend, the actual health degree of the sports industry, and the health degree of the supporting environment in the sports industry show a steady growth trend on the whole. In the next 10 years, the health degree of China’s sports industry will maintain a healthy state in which the actual health degree and potential health degree of the sports industry will enter a healthy state in 2021 and 2024, respectively. In contrast, the health degree of the supporting environment in the sports industry is always in a very unhealthy state.

Polymer-ceramic dielectric composites have been of great interest because they combine the processability of polymers with the desired dielectric properties of the ceramics. We fabricated a low voltage-operated flexible organic field-effect transistor (OFET) based on crosslinked poly (4-vinyl phenol) (PVP) polymer blended with novel ceramic calcium titanate nanoparticles (CaTiO₃ NPs) as gate dielectric. To reduce interface roughness caused by nanoparticles, it was further coated with a very thin PVP film. The resulting OFET exhibited much lower operated voltage (reducing from –10.5 V to –2.9 V), a relatively steeper threshold slope (~0.8 V/dec) than those containing a pure PVP dielectric. This is ascribed to the high capacitance of the CaTiO₃ NP-filled PVP insulator, and its smoother and hydrophobic dielectric surface proved by atomic force microscopy (AFM) and a water contact angle test. We also evaluated the transistor properties in a compressed state. The corresponding device had no significant degradation in performance when bending at various diameters. In particular, it operated well continuously for 120 hours during a constant bending stress. We believe that this technology will be instrumental in the development of future flexible and printed electronic applications.

In order to promote the coordinated development of the sports and pension industries, it is of great significance to apply the theory of industrial integration to the study of the interaction mechanism of the sports and pension industries, but there is a lack of research in this area at present. This paper firstly constructs the evaluation system of the coupling and coordination development of the sports and pension industries. Secondly, based on the panel data of 11 provinces and cities in the Yangtze River Economic Belt in 2013–2017, this paper analyzes the coupling and coordination relationship between the sports and pension industries by using the entropy method and the coupling coordination model. Finally, the coupling coordination relationship between the two industries in the region in the next five years is predicted using the grey model (1.1), i.e. GM (1.1) model. The results show the following: (1) The development level of the two major industries in 11 provinces and cities of the Yangtze River Economic Belt is generally on the rise, and they have a high correlation. (2) The sports industry is more volatile than the pension industry, and the sports industry has become an effective path dependence to narrow the regional development differences. The sports industry has a weak driving role in the pension industry, while the pension industry has a greater role in promoting the sports industry. (3) There is a large spatial difference in the coupling coordination degree of the sports and pension industries in 11 provinces and cities of the Yangtze River Economic Belt, which will remain in the next five years, though the evolution and upgrading speed of the coupling coordination level will be significantly accelerated.