[Objective/Significance] Hydrogen energy plays an increasingly prominent role in the layout of the world's emission reduction strategy. Japan, the United States, Europe and other developed countries have formulated hydrogen energy development policies and actively explored the technical route of the whole industrial chain of hydrogen energy manufacturing, storage, transportation and application. China has also taken hydrogen energy as one of the important options of the "double carbon" strategy. [Method/Process] This paper compares and analyzes the hydrogen energy policies of Japan, the United States, Europe and China, the world's hydrogen energy powerhouse, and uses the Incopat database as the source of patent data and the WOS core database as the source of paper data, and constructs a search formula using a combination of keywords and IPC patent classification numbers to explore the trends of technological research in different countries and regions in the last decade from the whole chain of hydrogen energy production, storage and transportation. [Results/Conclusions] Bibliometric analysis shows that China leads the world in the number of hydrogen invention patents, but there are still deficiencies in the overall quality of patents, patent R & D cooperation and transformation based on the frequency of patent citation. Based on the comparative analysis results of policy and technology, combined with China's reality, this paper puts forward three suggestions for China's hydrogen energy strategic layout, such as paying attention to the protection and innovation of intellectual property rights in the whole hydrogen energy industry chain, building a diversified commercial application mode of hydrogen energy, and improving the special planning and policy system.

[Objective/Significance] In order to provide the intelligence basis for relevant research and industry personnel, the international carbon farming research trend has been analyzed in this paper. [Method/Process] Bibliometric methods and knowledge map visualization software are used in this study, and we focus on the annual publication trend, the publication situation of major countries, the publication situation of major institutions, the situation of high impact papers and the distribution of research topics. In various aspects, quantitative statistics and qualitative comparative analysis of the global carbon farming papers have been finished. [Results/Conclusions] Carbon farming is getting more and more attention in recent years. The amount and influence of relevant research papers in different countries and institutions vary. Research topics mainly include plant and soil carbon/nitrogen organic matter, crops and climate change/greenhouse gas emissions, agroforestry and carbon capture or carbon fixation, crop cultivation and carbon sequestration, etc.

[Objective/Significance] Bioenergy with carbon capture and storage (BECCS) is a technology that combines bioenergy and carbon capture and storage (CCS) technology to achieve negative carbon emission. It plays an important role in coping with the challenges of sustainable utilization of resources, climate change and energy security and promoting the realization of the goal of "carbon peaking and carbon neutralization". [Method/Process] From the perspective of bibliometrics, this paper analyzes the development trend of scientific research and technology development related to BECCS. [Results/Conclusions] It is found that the global scientific research and technological development in the field of BECCS have shown an overall growth trend in recent years. China and the United States are countries with obvious leading advantages in this field. They are in a leading position in the number of papers, international cooperation, patent applications and patent layout, and have strong scientific research and technological development capabilities. Microalgae utilization and biodiesel preparation are the current research hotspots. Biomass conversion and utilization, carbon dioxide capture and transportation are the focus of technology development in recent years. In the next step, we should focus on improving the core research competitiveness in the field of BECCS, innovate and explore international scientific and technological cooperation, strengthen the development, transformation and application of advanced technologies, and help promote the implementation of China's strategy of building a scientific and technological power and the achievement of the goal of "carbon peaking and carbon neutralization".

[Objective/Significance] CCUS technology is the key technology to achieve carbon reduction goals, among which CO₂ conversion and utilization is an important part. [Method/Process] This study focuses on the development trends of CO₂ chemical conversion and utilization field. The basic data in the field of CO₂ chemical conversion and utilization in the past 20 years were chronodiced by using bibliometric method, and each decade was set as a time block. The development trend of the field in the two decades was compared and analyzed from the aspects of paper output scale, academic influence, international cooperation, journal and discipline distribution, research topics, etc. [Results/Conclusions] The results show that the current research is mainly focused on China and the United States. Compared with the first decade, China surpassed the United States in terms of paper size and academic influence in the second decade, while displacing the United States as the network center in international cooperation networks. The trends in recent ten years shows that the field of CO₂ chemical conversion and utilization ushered in a rapid development period. The research on the preparation of products shifted from CO₂ to degradable plastics to CO₂ to low olefin, and the research on the preparation process also shifted from hydropyrolysis to electrochemical reaction. The research in China focus in this field has shifted from CO₂ to formic acid and syngas to CO₂ to methanol and low olefin, while in the United States, the research focus has shifted from CO₂ to ammonia, methanol and biofuel to CO₂ to syngas.

[Purpose/Significance] To benefit from foreign experiences in the development of nanotechnology, this article provides an in-depth analysis of the 2021 National Nanotechnology Initiative (NNI) Strategic Plan. [Method/Process] After carefully reviewing of the history of NNI and recommendations for NNI from the U.S. science and technology community, [Results/Conclusions] the article concludes that to meet the challenge of global competition in science and technology and support the current and future needs of the U.S. nanotechnology community, NNI is redesigned with the new vision and goals and the strategies by which the organization and coordination of NNI and nanotechnology commercialization are to be enhanced. The purpose of the plan is to ensure that the United States remains a world leader in nanotechnology, not only the place where nanoscience discoveries are made but also where these discoveries are translated and manufactured into products to benefit society.