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Abstract The lack of electron donors in oxygen-rich aquatic environments limits the ability of natural denitrification to remove excess nitrate, leading to eutrophication of aquatic ecosystems. Herein, we demonstrate that electron-rich substances in river or lake sediments could participate in long-distance electron rebalancing to reduce nitrate in the overlying water. A microstructure containing Dechloromonas and consisting of an inner layer of green rust and an outer layer of lepidocrocite forms in the sediment-water system through synergetic evolution and self-assembly. The microstructure enables long-distance electron transfer from the sediment to dilute nitrate in the overlying water. Specifically, the inner green rust adsorbs nitrate and reduces the kinetic barrier for denitrification via an Fe(II)/Fe(III) redox mediator. Our study reveals the mechanism of spontaneous electron transfer between distant and dilute electron donors and acceptors to achieve denitrification in electron-deficient aquatic systems.

[Purpose/Significance] The livestock and poultry industry in China is in an important period of accelerating transformation. Understanding the research status of the related technology has certain reference significance for the development of the livestock and poultry industry. [Method/Process] This paper takes three main directions of the technology in the field of livestock and poultry farming facilities, cage, feeding and environment control, as the research object, and uses patentometrics to analyze the development trend, technology branch, applicant and key patents at all stages. [Results/Conclusions] The development of cage, feeding and environment control technology has experienced three stages simultaneously: germination stage, fluctuating development stage and rapid development stage, and the current application volume is on the rise in a straight line. Technology applications in this field mainly come from enterprises, and there are obvious differences in technology layout among enterprises. In recent years, the number of key patents from China has increased significantly. The research on cage technology devices is focused on technologies such as excrement and urine removal and floor covering. Research on feeding is more than that on drinking water, and both focus on automation equipment. Environment control focuses on waste treatment , air conditioning and house cleaning and scrubbing.

[Purpose/Significance] By analyzing the research situation of global smart agriculture, this paper aims to provide data reference and information support for scientific and technological innovation and management decision-making in the field of smart agriculture in China. [Method/Process] Based on the Web of Science database, this paper makes an in-depth analysis and visualization display of the global smart agriculture research overview, research group competitiveness, research focus and hot spots by using the methods of bibliometrics and knowledge mapping. [Results/Conclusions] Smart agriculture has drawn increasing interest among researchers both in and outside of China since 2010. The productivity and influence of China and the United States are far ahead of those of other countries in the world. The productivity and influence of China Agricultural University, Zhejiang University and the United States Department of Agriculture have obvious advantages. HE Y, JAYAS D S, and BLASCO J have higher productivity and influence, but the quality of papers of Chinese institutions and scholars is generally not rated as high. Agronomy, computer science, engineering, food science and technology, and chemistry are the key disciplines. Computers and Electronics in Agriculture is the most competitive journal. The global and China's smart agriculture can be divided into three research topics, but the research focus is different; the agricultural Internet of things as a representative of information perception, analysis and control technology is a research hotspot in recent years; agricultural sensor independent research and development, data mining analysis and sharing technology model, smart control algorithm model and system integration, smart agricultural machinery equipment and agriculture autonomous research and development of robots and smart agricultural science and technology service mode are the key research directions for further development of smart agriculture in China.

A simple method has been designed for constructing the coupling structure of m-NiFe@MnO2 ultra-thin nanosheet for oxygen evolution reaction on nickel foam. Intervention of the active component NiFe hydroxide not only promotes the dissociation of water but also reduces the energy barrier of the intermediate, while the presence of subsequent microwaves accelerates the electron transfer. m-NiFe@MnO2 showed excellent OER performance. This is prominently manifested in that when the current density reaches 100 mA cm−2, the overpotential is only 310 mV, which is far better than RuO2. The long-term (≥100 h) durability test also further proves its excellent stability.