Bidirectional enhancement of output performance of nanogenerators by M-COFs materials.

The emergence of nanogenerators, which have the ability to capture mechanical energy from the environment and to collect and transmit tiny energy, is rapidly becoming a hot research topic. The performance of electrode materials is the key to the efficiency of nanogenerators. Covalent organic skeletons (COFs), a class of crystalline organic porous materials with the advantages of large specific surface area, high porosity, tunable structure, and flexible tailorability, have very significant advantages in being used as nanogenerator materials. In this paper, we synthesised two COF materials to investigate the effect of the introduction of active metals on the friction power generation performance of COFs without changing their topology, COF-2 containing zinc ions is capable of generating a short-circuit current of 107.5 µA during friction. The porous structure increases the effective contact area to form a larger charge density, and the introduction of metal ions can accelerate the charge separation and transport. The two bidirectional synergistic effects of the materials significantly improve the output performance of the nanogenerator, and a simple and efficient method is explored for the enhancement of the output performance of COF-based triboelectric nanogenerators.

Multi-F-Structured MOF Materials Enhance Nanogenerator Output Performance for Corrosion Protection of Metallic Materials.

MOF (metal organic framework) materials have been used as functional materials in a number of fields due to their diverse spatial tunability, which produces rich porous structures with stable and continuous pores and a high specific surface area. A triboelectric nanogenerator can convert trace mechanical energy into electrical energy, and the application of MOF materials to triboelectric nanogenerators has been intensively studied. In this work, we report on two MOFs with similar spatial structures, and the modulation of the end microstructures was achieved using the difference in F content. The output performance of friction power generation increases with the increase in F content, and the obtained polyacidic ligand materials can be used to construct self-powered corrosion protection systems, which can effectively protect metallic materials from corrosion.

Directional design of carboxylic acid coordination number fine-tuned space structure to improve the output performance of nanogenerators.

The emergence of nanogenerators, which provide a way to obtain mechanical energy from the environment and to collect and transmit tiny amounts of energy, has attracted a lot of attention. MOFs, because of their diverse structures as well as stable pores and large specific surface area, have very significant advantages to be used as nanogenerator materials. In this paper, two MOFs with similar spatial structures are designed to take advantage of the different coordination numbers of carboxylic acids to achieve the regulation of their microstructures. The output performance of friction power generation was found to be affected significantly by their microstructures. The friction power generation performance improved with the increase of carboxylic acids, and the obtained polyacid ligand materials can be used for light bulb illumination, which is a step forward for the practical exploration.

[Microbial activity and functional diversity in rhizosphere of cucumber under different subsurface drip irrigation scheduling].

The effects of subsurface drip irrigation scheduling on microbial activity and functional diversity in rhizosphere of cucumber in solar greenhouse were studied in this paper. The results showed that the soil microbial biomass C and N, basal respiration, metabolic quotient and values of AWCD, Shannon and McIntosh indexes were increased at first and then decreased with the increase of irrigation water amount. The values of microbial C and N, basal respiration and metabolic quotient in I2 treatments were significantly higher than those in I1 treatments at the 0.8E(p) irrigation level. The numbers of bacteria, actinomyces and nitrogen-fixing bacteria, and the activities of urease, phosphatase, sucrase, catalase and polyhenoloxidase were significantly higher in the 0.8E(p) treatment than in the other treatments. The numbers of bacteria and nitrogen-fixing bacteria, the activities of urease, phosphatase and sucrase in I2 treatments were significantly higher than in I1 treatment, the actinomyces number and activities of catalase and polyhenoloxidase had no significant difference between I1 and I2 treatments, however, the fungi number in I2 treatments were significantly lower than in I2 treaments at the 0.8E(p) irrigation level. The microbial activity and functional diversity in rhizosphere of cucumber were strengthened in the I20.8E(p) treatment, meanwhile, the soil microflora was improved and the soil enzymes activities were enhanced, therefore, the cucumber growth was promoted as well.

[Effects of grafting on root polyamine metabolism of cucumber seedlings under copper stress].

By the method of hydroponic culture, and taking Cucurbita ficifolia B. as rootstock, this paper studied the effects of grafting on the root polyamine metabolism of cucumber seedlings under copper stress. The results showed that under copper stress, the root activities of cucumber seedlings were inhibited, and electrolyte leakage increased, with these changes being significantly lower for grafted than for ungrafted cucumber seedlings. In addition, the contents of free spermidine and spermine, and of conjugated and bound polyamines were significantly higher in grafted than in ungrafted seedling roots, while the free putrescine content and the ratio of free putrescine to polyamines were on the contrary. Comparing with those in ungrafted cucumber seedlings, the root arginine decarboxylase (ADC), ornithine decarboxylase (ODC), and S-adenosylmethionine decarboxylase (SAMDC) activities in grafted cucumber seedlings were higher, while the diamine oxidase and polyamine oxidase activities were significantly lower. All of these indicated that under copper stress, the synthesis of polyamine in grafted seedling roots was increased, while the degradation of polyamine was decreased, resulting in a higher accumulation of polyamine in the roots, and the increase of the tolerance of cucumber seedlings to copper stress.

[Effects of grafting on cucumber rhizospheric soil microbial characteristics and enzyme activities under copper stress].

A pot experiment with cucumber (taking Cucurbita ficifoblia B. as the rootstock) was conducted to study the effects of grafting on the microbial population, microbial biomass, and enzyme activities in rhizospheric soil under copper stress. Under the stress of copper, the microbial biomass C and N in grafted and self-rooted cucumber rhizospheric soils all decreased significantly, while the basal respiration and metabolic quotient were in adverse. In grafted cucumber rhizospheric soil, the microbial biomass C and N were significantly higher than those in self-rooted cucumber rhiaospheric soil, whereas the basal respiration and metabolic quotient were significantly lower. Under copper stress, the quantities of actinomyces and nitrogen-fixing bacteria in rhizospheric soils decreased and that of fungi increased significantly, whereas the quantity of bacteria had less change. In grafted cucumber rhizospheric soil, the quantities of bacteria, actinomyces, and nitrogen-fixing bacteria were significantly higher than those in self-rooted cucumber rhizospheric soil, but the quantity of fungi was in opposite. The urease, phosphatase, sucrase, and catalase activities were significantly higher in grafted than in self-rooted cucumber rhizospheric soil. All the results suggested that grafting could mitigate the impact of copper stress on the microbial micro-environment and enzyme activities in cucumber rhizospheric soil, and as a result, improve the adaptability of cucumber to copper stress.