35 research outputs found
Enhanced bending-tuned magnetic properties in epitaxial cobalt ferrite nanopillar arrays on flexible substrates
Herein, large-scale epitaxial (111) CoFe2O4 nanopillar arrays with an average nanopillar diameter of ∼40–60 nm and thicknesses of 26–700 nm have been obtained on flexible fluorophlogopite substrates by chemically etching the vertically aligned self-assembled CoFe2O4:MgO nanocomposite thin films. The chemical etching process has not affected the crystalline quality of the CoFe2O4 phase, but results in volume shrinkage through the removal of the surrounding MgO phase. Compared with the planar CoFe2O4 films, the nanopillar arrays show sharply declined coercivity and enhanced saturation magnetization. Even the thinnest nanoisland-shaped arrays (∼26 nm) retain a relatively high saturation magnetization (∼90 emu cc−1), nonzero coercivity (∼250 Oe), and remanence (∼30 emu cc−1), which are promising for the requirements of weak ferromagnetism in flexible devices. With an increase in the bending radius, a strong and monotonous increase in saturation/remanent magnetization has been found in the nanopillar arrays. This reveals that the bending-induced shape anisotropy as well as the intrinsic magnetocrystalline anisotropy mainly dominate the tunable magnetic properties in the CoFe2O4 nanopillar arrays. With strong bending, the increment of remanent magnetization in the nanopillar arrays can be as high as 98%, exhibiting the huge potential of these nanopillar arrays in future applications such as in bending sensors and related devices
Genome-wide investigation and expression pattern of PHR family genes in cotton under low phosphorus stress
Phosphorus starvation response (PHR) protein is an important transcription factor in phosphorus regulatory network, which plays a vital role in regulating the effective utilization of phosphorus. So far, the PHR genes have not been systematically investigated in cotton. In the present study, we have identified 22, 23, 41 and 42 PHR genes in G. arboreum, G. raimondii, G. hirsutum and G. barbadense, respectively. Phylogenetic analysis showed that cotton PHR genes were classified into five distinct subfamilies. The gene structure, protein motifs and gene expression were further investigated. The PHR genes of G. hirsutum from the same subfamily had similar gene structures, all containing Myb_DNA-binding and Myb_CC_LHEQLE conserved domain. The structures of paralogous genes were considerably conserved in exons number and introns length. The cis-element prediction in their promoters showed that genes were not only regulated by light induction, but also were related to auxin, MeJA, abscisic acid-responsive elements, of which might be regulated by miRNA. The expression analysis showed that the GhPHR genes were differentially expressed in different tissues under various stresses. Furthermore, GhPHR6, GhPHR11, GhPHR18 and GhPHR38 were significantly changed under low phosphorus stress. The results of this study provide a basis for further cloning and functional verification of genes related to regulatory network of low phosphorus tolerance in cotton
Flexible Lithium Ferrite Nanopillar Arrays for Bending Stable Microwave Magnetism
Recent development in magnetic nanostructures has promoted flexible electronics into the application of integrated devices. However, the magnetic properties of flexible devices strongly depend on the bending states. In order to realize the design of new flexible devices driven by an external field, the first step is to make the magnetic properties insensitive to the bending. Herein, a series of LiFe5O8 nanopillar arrays were fabricated, whose microwave magnetic properties can be modulated by tuning the nanostructure. This work demonstrates that nanostructure engineering is useful to control the bending sensitivity of microwave magnetism and further design stable flexible devices
Biomorphic Synthesis of Mesoporous Co<sub>3</sub>O<sub>4</sub> Microtubules and Their Pseudocapacitive Performance
A novel meosoporous tubular Co<sub>3</sub>O<sub>4</sub> has been fabricated by a simple and cost-effective
biomorphic synthesis route, which consists of infiltration of cotton
fiber with cobalt nitrate solution and postcalcination at 673 K for
1 h. Its electrochemical performance as a supercapacitor electrode
material is investigated by means of cyclic voltammetry and chronopotentiometry
tests. Compared with bulk Co<sub>3</sub>O<sub>4</sub> prepared without
using cotton template, biomorphic Co<sub>3</sub>O<sub>4</sub> displays
2.8 fold enhancement of pseudocapacitive performance because of the
unique tubular morphology, relative high specific surface area (3
and 0.8 m<sup>2</sup>/g for biomorphic Co<sub>3</sub>O<sub>4</sub> and bulk Co<sub>3</sub>O<sub>4</sub>, respectively), and mesoporous
nature