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The purpose of this study is to examine the spatial fluctuation spillover effect of green total factor productivity (GTFP) under the influence of Internet development.

Using panel data from 283 cities in China for the period 2003–2016, this paper explores the spatial fluctuation spillover effect of internet development on GTFP by applying the spatial autoregressive with autoregressive conditional heteroscedasticity model (SARspARCH).

The results of Moran's I test of the residual term and the Bayesian information criterion (BIC) value indicate that the GTFP has a spatial fluctuation spillover effect, and the estimated results of the SARspARCH model are more accurate than the spatial autoregressive (SAR) model and the spatial autoregressive conditional heteroscedasticity (spARCH) model. Specifically, the internet development had a positive spatial fluctuation spillover effect on GTFP in 2003, 2011, 2012 and 2014, and the volatility spillover effect weakens the positive spillover effect of internet development on GTFP. Moreover, Internet development has a significant positive spatial fluctuation spillover effect on GTFP averagely in eastern China and internet-based cities.

The results of this study provide digital solutions for policymakers in improving the level of GTFP in China, with more emphasis on regional synergistic governance to ensure growth.

This paper expands the research ideas for spatial econometric models and provides a more valuable reference for China to achieve green development.

This paper aims to determine whether application of graphene layers to cuprammonium filaments affords the latter with excellent mechanical properties and improves their electrical properties. At the same time, a circuit model was established to explore the conductive mechanism of the filament. The actual model is used to verify the correctness of the model.

The cuprammonium filaments were desizing, the graphene oxide layer-by-layer sizing and reduction integration process by a continuous sizing machine. The electrical properties of mono- and multifilaments in the static condition, as well as the dynamic–mechanical properties of multifilaments, were analysed, and the related conductive mechanism of the filaments was deduced.

Cuprammonium filaments coated with graphene layers showed good electrical conductivity, and their volume resistance decreased to 4.35 O·cm with increasing number of graphene coats. The X-ray diffraction and thermogravimetric analysis results showed that the graphene layer treatment changed the crystallinity of the copperammonia filaments and improved the thermal stability of the filaments. In the dynamic case, filament resistance was calculated using the equivalent resistance model, and the fitting difference observed was small. This result confirmed the high fit of this circuit model.

Up to the knowledge from literature review, there are no reports on theoretical research on the relation between the electro-mechanical property and structure of conductive filaments.