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  • Author: Z.B. Pan x
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Dynamic magnetoelastic properties of TbxHo0.9−xNd0.1(Fe0.8Co0.2)1.93/epoxy composites

Abstract

TbxHo0.9−xNd0.1(Fe0.8Co0.2)1.93/epoxy (0 ⩽ x ⩽ 0.40) composites are fabricated in the presence of a magnetic field. The structural and dynamic magnetoelastic properties are investigated as a function of both magnetic bias field Hbias and frequency f at room temperature. The composites are formed as textured orientation structure of 1–3 type with 〈1 0 0〉 preferred orientation for x ⩽ 0.10 and 〈1 1 1〉-orientation for x ⩾ 0.25. The composites generally possess insignificant eddy-current losses for frequency up to 50 kHz, and their dynamic magnetoelastic properties depend greatly on Hbias. The elastic modulus (E3 H and E3 B) shows a maximum negative ΔE effect, along with a maximum d33, at a relatively low Hbias ~ 80 kA/m, contributed by the maximum motion of non-180° domain-wall. The 1–3 type composite for x ⩾ 0.25 shows an enhanced magnetoelastic effect in comparison with 0 to 3 type one, which can be principally ascribed to its easy magnetization direction (EMD) towards 〈1 1 1〉 axis and the formation of 〈1 1 1〉-texture-oriented structure in the composite. These attractive dynamic magnetoelastic properties, e.g., the low magnetic anisotropy and d33 , max as high as 2.0 nm/A at a low Hbias ~ 80 kA/m, along with the light rare-earth Nd element existing in insulating polymer matrix, would make it a promising magnetostrictive material system.

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Genetic parameters and prediction of breeding values in Castanopsis hystrix A.DC. for growth and form traits

Abstract

Castanopsis hystrix A.DC. is one of the most important and multipurpose tree species native to China. 157 open-pollinated families collected from 11 provenances in Guangdong, Guangxi, and Fujian province were used to estimate genetic parameters for height (H), diameter at breast height (DBH), ground diameter (GD), and crown width (CW) for each province and combined three provinces at ages from 3 to 9 years. The variance component was small and non-significant among provenances but was highly significant among families within provenances for H, DBH, GD, and CW. Heritability estimates were significant except for a few traits from Fujian’s provenances. Heritability ranged from 0.20 to 0.57 for H, 0.19 to 0.38 for DBH, 0.21 to 0.55 for GD, and 0.09 to 0.39 for CW. Heritability estimates for H and DBH decreased with increased age for each province and combined three provinces. Significantly high genetic correlations were observed for ageage and trait-trait correlations, indicating that genetic performance at one trait was well correlated with another trait. In total, 22 families and 60 individuals were selected for backward and forward selection based on breeding values.

Open access