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Single-crystal semi-polar (112¯2) AlN films are grown on 2-inch m-plane sapphire substrates by high-temperature hydride vapor phase epitaxy (HVPE). The introduction of the sapphire nitridation pretreatment and low-temperature AlN buffer layer suppresses the formation of undesired (101¯3) and (101¯1) AlN, leading to the desired single-crystal (112¯2) AlN film. The high growth temperature promotes a shift in growth mode from three-dimensional islands to two-dimensional step flow. This facilitates grain coalescence, resulting in the formation of well-defined macro steps on the (112¯2) AlN surface. The 9.02 μm-thick (112¯2) AlN film exhibits excellent crystalline quality, as evidenced by the narrow full widths at half maximum of 547′′ and 634′′ for the X-ray rocking curves measured along the [112¯3]AlN and [11¯00]AlN directions, respectively. The surface of the 2-inch (112¯2) AlN film is free of cracks and unmerged grains, providing a suitable substrate for the subsequent epitaxial growth of (112¯2) AlN light emitter layers. [ABSTRACT FROM AUTHOR]

Smooth and crack-free (0002) AlN thick films (∼30 μm) were epitaxially grown on trench-patterned AlN/sapphire templates through epitaxial lateral overgrowth (ELO) using hydride vapor phase epitaxy. The trenches on AlN/sapphire templates were oriented along [10−10]AlN, where the width of terraces and grooves was 8 μm and 4 μm, respectively. A comprehensive study was conducted on the influence of growth pressure on the morphology, crystal quality, and residual stress of the AlN thick films. As the growth pressure decreased from 40 torr to 20 torr, the lateral-to-vertical growth rate ratio of AlN increased, facilitating faster coalescence of separated AlN terraces to form a continuous film. Triangular voids were formed during the coalescence of AlN terraces, with the largest void size being observed at 20 torr due to the fastest coalescence. These triangular voids prevented the propagation of threading dislocations into the epitaxial layer, promoting their merging into loops and annihilation, while also releasing residual stress in the AlN film. As the growth pressure decreased, these triangular voids gradually became larger, accompanied by a reduction in etch pit density and residual stress in the AlN film. Compared to the initial AlN/sapphire template, the etch pit density of the AlN thick film grown by ELO at 20 torr decreased from 1.1 × 108 cm−2 to 3 × 107 cm−2, while the residual stress was reduced from 1.4 GPa to 0.4 GPa. [ABSTRACT FROM AUTHOR]

AlN epilayers were grown on magnetron-sputtered (MS) (11–22) AlN buffers on m-plane sapphire substrates at 1450 °C via hydride vapour phase epitaxy (HVPE). The MS buffers were annealed at high temperatures of 1400–1600 °C. All the samples were characterised using X-ray diffraction, atomic force microscopy, scanning electron microscope and Raman spectrometry. The crystal quality of epilayers regrown by HVPE was improved significantly compared to that of the MS counterpart. With an increasing annealing temperature, the crystal quality of both MS buffers and AlN epilayers measured along [11–23] and [1–100] improved first and then decreased, maybe due to the decomposition of MS buffers, while the corresponding anisotropy along the two directions decreased first and then increased. The optimum quality of the AlN epilayer was obtained at the annealing temperature of around 1500 °C. In addition, it was found that the anisotropy for the epilayers decreased significantly compared to that of annealed MS buffers when the annealing temperature was below 1500 °C. [ABSTRACT FROM AUTHOR]

Lodging is an important factor that restricts the yield of rapeseed and the mechanical harvesting. To explore agricultural practise and mechanisms that can synergistically improve the rapeseed yield and lodging resistance, a conventional plant type HZ 62 was selected in 2016–2017, and HZ 62 and an erect‐leaf type 1,301 were grown in 2017–2018. The planting density was set as main plots at 15 × 104 plants ha1 (D1), 30 × 104 plants ha‐1 (D2) and 45 × 104 plants ha−1 (D3), with the row spacing as sub‐plots of 15 cm (R15), 25 cm (R25) and 35 cm (R35). The results showed that with increased density and narrowed row spacing, the radiation utilisation efficiency (RUE) of the population and seed yield were greatly increased. Compared with that at D1R25, the yield of HZ 62 at D3R15 was increased by 19.00% and 22.53%, respectively, in 2016–2017 and 2017–2018, whereas the yield of 1,301 rose by 31.98%. The influence of the RUE on the seed yield reached the peak at flowering stage. With increased planting density and narrowed row spacing, the lodging index of HZ 62 declined. The lodging index of 1,301 was increased with higher density and declined with narrowed row spacing. Compared with D1R25, the averaged lodging index across different parts of HZ 62 at D3R15 declined by 15.03% and 10.80%, respectively, in 2016–2017 and 2017–2018, and that of 1,301 was increased by 25.47%. Compared with D1R25, the stem proteomics during the flowering stage showed the expression of photosynthesis‐related proteins (A0A078FHG9, A0A078JZM9 and A0A078JQI2) up‐regulated, that consistent with Rubisco, SPS and FBPase activities; proteins related to phenylpropanes metabolism, A0A078IWR4 of HZ 62 and A0A078JWZ9 of 1,301 increased that consistent with POD activity, which resulted in more sucrose, starch and lignin in the stem at D3R15. Moreover, the protein related to cellulose synthesis (A0A078I4D9), the activity of β‐1,3‐glucanase and content of cellulose in the stem were up‐regulated in HZ 62 but down‐regulated in 1,301, contrary to the variation in the stem lodging index. The cellulose synthesis differed between the varieties in different treatment combinations of planting density and row spacing. This was the key process by which planting density and row spacing influence the lodging of rapeseed varieties with varied plant architecture. [ABSTRACT FROM AUTHOR]

Inclusions inevitably exist in steel plate, whose behaviour during rolling severely affects the quality of product. In this article, a finite element method was used to simulate the hot rolling behaviour of hard and soft inclusions in high silicon steel plates at different sizes, positions and shapes (circle and square) when the adhesion to the matrix were weak. The shape, relative position and dimensions around the inclusions after rolling were obtained. When the inclusions are hard, cracks are produced around the inclusions after rolling. When inclusions are soft, there are no cracks around the inclusions. Large hard inclusions are more likely to move to the plate surface. When the inclusions are in the position of 1/16 of the sheet, the relative distance between the inclusions and the surface of the sheets is significantly reduced, from 0.062 at the beginning to less than 0.02. Furthermore, the effect of the size and location of hard inclusions on the microscopic defects produced after rolling is discussed. The microscopic defects around the inclusions increase with increasing size and decreasing distance of the inclusions. [ABSTRACT FROM AUTHOR]