Nanodiamond Coating in Energy and Engineering Fields: Synthesis Methods, Characteristics, and Applications.

Nanodiamonds are metastable allotropes of carbon. Based on their high hardness, chemical inertness, high thermal conductivity, and wide bandgap, nanodiamonds are widely used in energy and engineering applications in the form of coatings, such as mechanical processing, nuclear engineering, semiconductors, etc., particularly focusing on the reinforcement in mechanical performance, corrosion resistance, heat transfer, and electrical behavior. In mechanical performance, nanodiamond coatings can elevate hardness and wear resistance, improve the efficiency of mechanical components, and concomitantly reduce friction, diminish maintenance costs, particularly under high-load conditions. Concerning chemical inertness and corrosion resistance, nanodiamond coatings are gradually becoming the preferred manufacturing material or surface modification material for equipment in harsh environments. As for heat transfer, the extremely high coefficient of thermal conductivity of nanodiamond coatings makes them one of the main surface modification materials for heat exchange equipment. The increase of nucleation sites results in excellent performance of nanodiamond coatings during the boiling heat transfer stage. Additionally, concerning electrical properties, nanodiamond coatings elevate the efficiency of solar cells and fuel cells, and great performance in electrochemical and electrocatalytic is found. This article will briefly describe the application and mechanism analysis of nanodiamonds in the above-mentioned fields.

Corrosive effect on saturated pool boiling heat transfer characteristics of metallic surfaces with hierarchical micro/nano structures.

Surface modification is of critical interest to enhance boiling heat transfer in terms of heat transfer coefficient or critical heat flux (CHF), which is significantly affected by distinct surface morphology and wettability and it can improve the efficiency and safety of equipment. Furthermore, actual service environment may cause severe corrosion to the processed structured surfaces while its consequence on boiling heat transfer is still obscure. In this article, comprehensive researches are conducted to unravel corrosive effect on metallic samples made of stainless steel (SS) and Inconel materials with microstructures. Different constructions (i.e., microgroove, microcavity and micropillar array) and characteristic dimensions (∼20, 50 µm) of microstructure, various duration time (up to 300 days) and pH values (∼7.0-8.5) of corrosive environment are compared thoroughly. Conclusions can be drawn that not all microstructures can enhance pool boiling heat transfer characteristics, especially in terms of CHF values. More importantly, CHF value of SS microgroove sample firstly increases from 60.94 to 94.09 W·cm-2 in 50 days, then decreases to 47.77 W·cm-2 in 300 days, which can be attributed to competition result between formation of hierarchical micro/nano structure with enhancing wicking capability and chemistry condition with increasing contact angle. In addition, distinct bubble dynamics during pool boiling is also analyzed. The insights obtained from this article can be used to guide surface modification method and to reveal evolvement rule of engineered metallic surface in highly corrosive and harsh boiling heating transfer environment.

ARBUSCULAR MYCORRHIZA-INDUCED KINASES AMK8 and AMK24 associate with the receptor-like kinase KINASE3 to regulate arbuscular mycorrhizal symbiosis in Lotus japonicus.

Arbuscular mycorrhizal (AM) symbiosis is a widespread, ancient mutualistic association between plants and fungi, and facilitates nutrient uptake into plants. Cell surface receptor-like kinases (RLKs) and receptor-like cytoplasmic kinases (RLCKs) play pivotal roles in transmembrane signaling, while few RLCKs are known to function in AM symbiosis. Here, we show that 27 out of 40 AM-induced kinases (AMKs) are transcriptionally upregulated by key AM transcription factors in Lotus japonicus. Nine AMKs are only conserved in AM-host lineages, among which the SPARK-RLK-encoding gene KINASE3 (KIN3) and the RLCK paralogues AMK8 and AMK24 are required for AM symbiosis. KIN3 expression is directly regulated by the AP2 transcription factor CTTC MOTIF-BINDING TRANSCRIPTION FACTOR1 (CBX1), which regulates the reciprocal exchange of nutrients in AM symbiosis, via the AW-box motif in the KIN3 promoter. Loss of function mutations in KIN3, AMK8, or AMK24 result in reduced mycorrhizal colonization in L. japonicus. AMK8 and AMK24 physically interact with KIN3. KIN3 and AMK24 are active kinases and AMK24 directly phosphorylates KIN3 in vitro. Moreover, CRISPR-Cas9-mediated mutagenesis of OsRLCK171, the sole homolog of AMK8 and AMK24 in rice (Oryza sativa), leads to diminished mycorrhization with stunted arbuscules. Overall, our results reveal a crucial role of the CBX1-driven RLK/RLCK complex in the evolutionarily conserved signaling pathway enabling arbuscule formation.