This paper describes the significance, content, progress and corresponding basic theory and experimental research methods of micron/nanometer scale thermal science and engineering, which is one of the latest cutting-edge disciplines, and analyzes the effects of micron nanometer devices on the scale effect series of challenging hot issues, discussed the corresponding emergence of some new phenomena and new concepts, pointed out that the micron/nano thermal science aspects of the recent development of several types of theory and experimental technology success and shortcomings, and summed up a number for the exploration of the new ways and new directions, especially on some typical micron/nano-thermal devices and micro-scale biological heat transfer in some important scientific issues and their engineering applications were introduced.

The interest in smart grids and new technologies is growing around the world. Countries are investing in the development of new technologies that will help achieve environmental goals, energy supply efficiency, improve energy efficiency and increase consumer involvement in the energy generation. One of such technology is a blockchain. It is believed that the blockchain, combined with a smart grid, provides an opportunity to integrate the activities of all stakeholders, including: generators, distributors and consumers of electricity. The aim of the article is to identify the key research areas discussed by the researchers of both the smart grid and the blockchain issues. An analysis of the Scopus database from 2015 to 2023 was conducted. Using a created bibliometric query, a systematic literature review was conducted. 476 scientific publications relating to the issues addressed were identified. Using the VOSviewer software, a bibliometric analysis was performed using the author’s keywords. The bibliometric maps obtained allowed for the identification of key research areas. The article also presents potential future directions of scientific considerations, which should be focused on the issue of green smart grid and green blockchain. The results presented in the article can inspire researchers looking for research gaps or describing the current state of knowledge in the field of the smart grid and the blockchain issues.

In the last few decades, nano-electronic devices have been manufactured using VLSI technology. Over the past four decades, IC technology has been growing by using CMOS technology successfully, but this CMOS technology has a scaling limitation. To overcome this scaling limitation, QCA (quantum dot cellular automata) emerges as an alternative. This work is the implementation of the design of a polar encoder using QCA technology. This design is a single-layered and even bottom-up approach technique. The Polar code is more efficient and has less energy dissipation compared to the turbo code and conventional codes (CC). This design explores (8:4). A Polar encoder is designed to have fewer cells and area compared to the turbo encoder and conventional encoder. The proposed design is implemented using the QCA designer tool.

The holding of soccer events has an important impact on modern urban activities, which is conducive to the economic development, social harmony, cultural integration and regional integration of cities. However, massive energy is consumed during the event preparation and infrastructure construction, resulting in an increase in the city’s carbon emissions. For the sustainable development of cities, it is important to explore the theoretical mechanism and practical effectiveness of the relationship between soccer events and urban carbon emissions, and to adopt appropriate policy management measures to control carbon emissions of soccer events. With the development of green technology, digitalization, and public transportation, the preparation and management methods of soccer events are diversified, and the possibility of carbon reduction of the event is further increased. This paper selects 17 cities in China from 2011 to 2019 and explores the complex impact of soccer events on urban carbon emissions by using green technology innovation, digitalization level and public transportation as threshold variables. The results show that: (1) Hosting soccer events increases carbon emissions with an impact coefficient of 0.021; (2) There is a negative single-threshold effect of green innovation technology, digitalization level and public transportation on the impact of soccer events on carbon emissions, with the impact coefficients of soccer events decreasing by 0.008, 0.01 and 0.06, respectively, when the threshold variable crosses the threshold. These findings will enhance the attention of city managers to the management of carbon emissions from soccer events and provide guidance for reducing carbon emissions from soccer events through green technology innovation, digital means and optimization of public transportation.