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With the wide application of nanocomposite protective coatings in various fields, there are higher requirements for their properties. At the same time, the traditional chemical deposition and electrodeposition processes have defects with different degrees. Nanocomposite coating was prepared by pulse current assisted chemical deposition process, which has the advantages of effectively improving the chemical deposition rate and ensuring the uniformity and compactness of the deposition layer surface morphology. In this paper, the effect of different duty ratios on Ni–P-(sol)Al2O3 nanocomposite deposition was studied. The surface morphology, composition, hardness, wear resistance and elastoplastic mechanical properties of the nanocomposite coating were tested through experiments. The experimental results showed that, when the duty ratio of pulse current was 20%, the prepared Ni–P-(sol)Al2O3 nano-composite deposition layer has the best performance, and its deposition rate reached 45.99 μm/h, hardness value was 629 HV, friction coefficient was 0.395, wear-width was 126.33 μm, Young modulus was 135.216 GPa, elastic recovery ratio he/hmax reached the maximum value of 0.3976, H3/E2 reached the maximum value of 0.0505 GPa. Compared with the coatings prepared by the traditional chemical deposition process, it is found that both coatings show good compactness and uniformity. However, the pulse-assisted chemical deposition method is significantly superior to the latter in hardness and wear resistance. The deposition layer prepared by pulse-assisted chemical deposition not only has a uniform and compact surface, but also has high hardness, good toughness and optimal wear resistance.

In this study, the problems of the low deposition rate and bath instability in chemical deposition can be effectively solved by using the pulsed current-assisted chemical deposition process when preparing Ni–P alloy coating. Orthogonal experiments were designed by changing the average current density, pulse frequency and duty ratio of the pulses to study their effects on the deposition rate and hardness of the coatings. Compact Ni–P coating with uniform surface morphology and good performance was prepared by parameter optimization. The results show that our method can greatly improve the deposition rate while ensuring the surface quality and performance of the deposited layer.

In order to alleviate the agglomeration of nanoparticles in the plating solution, the dispersion effect of binary nanoparticles in Ni–P–Al2O3–PTFE composite coating was studied by physical and chemical dispersion methods. The effects of different dispersion methods on the microstructure, hardness and friction coefficient of the composite coating were discussed. Through the performance evaluation of the composite coating, it is found that the effect of using appropriate dispersant and ultrasonic dispersion process is good, which can make the nanoparticles fully dispersed in the solution and evenly distributed in the coating, the composite amount of nanoparticles in the deposition layer is also high. The results show that it has a good effect on improving the wear-resisting and antifriction properties of the composite coatings.

The scutellum, coleoptile, coleorhiza, and epiblast (if it exists) consist of a complex embryonic envelope to protect the plumule and radicle inside a grass embryo. Controversies have been provoked for centuries regarding homologies of the grass embryonic structures. Here we found that the rice LEAFY COTYLEDONE1 (LEC1) gene, OsNF-YB7, is vital for embryo development. A leaf-like structure (LL) was developed from the scutellum of osnf-yb7 to replace the embryonic envelope that formed in wild-type. Additionally, osnf-yb7 developed chloroembryos due to overactivated chlorophyll biosynthesis. Thus, OsNF-YB7 likely plays a dual role in chlorophyll biogenesis in rice embryos: (1) OsNF-YB7 directly represses genes, such as rice GOLDED-LIKE1 (OsGLK1), involving chlorophyll biosynthesis; (2) OsNF-YB7 binds to OsGLK1 to repress the downstream genes of OsGLK1. Parallel phenotypes shown in osnf-yb7 and lec1 suggest functional conservation of the LEC1-type genes in plants. Both lec1 cotyledons and osnf-yb7 LL displayed true leaf characteristics. Our morphological and transcriptional evidence implied that LL replaces the embryonic envelope in osnf-yb7, raising the hypothesis that the grass embryonic envelope is an analog of Arabidopsis cotyledon. This study demonstrates that OsNF-YB7 acts as a negative regulator in chlorophyll biogenesis and is important for embryonic envelope formation.

Improvements in plant architecture, such as reduced plant height under high-density planting, are important for agricultural production. Light and gibberellin (GA) are essential external and internal cues that affect plant architecture. In this study, we characterize the direct interaction of distinct receptors that link light and GA signaling in Arabidopsis (Arabidopsis thaliana) and wheat (Triticum aestivum L.). We show that the light receptor CRY1 represses GA signaling through interaction with all five DELLA proteins and promotion of RGA protein accumulation in Arabidopsis. Genetic analysis shows that CRY1-mediated growth repression is achieved by means of the DELLA proteins. Interestingly, we find that CRY1 also directly interacts with the GA receptor GID1 to competitively inhibit the GID1-GAI interaction. We also show that overexpression of TaCRY1a reduces plant height and coleoptile growth in wheat and that TaCRY1a interacts with both TaGID1 and Rht1 to competitively attenuate the TaGID1-Rht1 interaction. Based on these findings, we propose that the photoreceptor CRY1 competitively inhibits the GID1-DELLA interaction, thereby stabilizing DELLA proteins and enhancing their repression of plant growth., The photoreceptor CRY1 interacts directly with both GID1 and DELLA proteins in a blue light-dependent manner to competitively inhibit the GID1-DELLA interaction, thereby stabilizing DELLA proteins and enhancing their repression of plant growth.

Accurate detection and analysis of the cathode surface temperature delivers an important reference value as regards the prediction of electrode life and corrosion degree, a thorough study of the vacuum-breakdown phenomenon, design and application of the vacuum-arc ion source and vacuum switch. In this paper, multispectral true temperature measurement T of the surface temperature field of pulsed vacuum arc cathode materials under different discharge currents is carried out. Firstly, aiming at solving the problem of synchronous imaging measurement of the temperature field across the cathode of pulsed vacuum arc, a multi-wavelength monochromatic image-acquisition optical path is designed, based upon the image acquisition module of a high-speed monochrome camera. Also, multiple monochromatic spectral radiation images of the target are synchronously acquired on the focal plane of the same monochrome camera detector. As a result, the spectral-radiation image information of multiple wavelengths can be obtained in a single exposure time, which greatly shortens the temperature-field image acquisition time. Secondly, based upon the multispectral true-temperature calculation method, high-speed multispectral imaging measurement of the target temperature field is realized. Finally, the two-dimensional true temperature distribution of the cathode temperature field under different current conditions was studied by setting up an experimental platform for measuring the cathode temperature of the vacuum arc under different current conditions.