Large-Scale Synthesis and Raman and Photoluminescence Properties of Single Crystalline β-SiC Nanowires Periodically Wrapped by Amorphous SiO₂ Nanospheres 2

Novel SiC/SiO2 chainlike nanostructures have been synthesized via a simple template/catalyst-free chemical vapor reaction approach using Si−SiO2 mixture powder and CH4 as raw materials at relatively low temperatures of 1250−1200 °C. Digital camera, stereoscope, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, and infrared spectroscopy demonstrate that large-scale blue products have been obtained on graphite substrate; the samples are composed of chainlike nanostructures having lengths up to several tens of micrometers, diameters of 20−30 nm single crystalline β-SiC nanowires, and 80−100 nm amorphous SiO2 periodic wrapping spheres, possessing [111] preferred growth direction with a high density stacking faults and twin defects. We suppose the formation of the nanostructure is induced by two-stage VS growth mechanism, especially because the defects within SiC nanowires are the critical factors for the second-stage formation of SiO2 spheres. Some unique optical properties are observed in the room-temperature Raman spectroscopy and photoluminescence measurements of the products, which may be ascribed to crystal defects and size confinement effects

Appearances of transgenic lines and non-transgenic plants after 30 days of salt stress.

<p>A photograph showing <i>TaLEA</i>-transformed and WT poplar plants after 30 days of salt stress. T11: transgenic line 11; WT: wild type.</p

Effect of <i>TaLEA</i> transgene expression on malondialdehyde (MDA) content and electrolyte leakage of Poplars.

<p>Histograms showing A: MDA content comparison. B: Relative electrolyte leakage comparison; control: normal condition; salt stress: 200 mM NaCl treatment for 6 d; drought stress: withholding water for 7 d between WT and <i>TaLEA</i>-transformed poplars. At least five plants from each line were used for biological repeats in each experiment. Values are means ± S.D. and the level of significance was set at <i>P</i> < 0.05. The stars above the bars indicate significant differences (<i>P</i> < 0.05) between the transgenic lines compared with WT under the test conditions.</p

RT-PCR and RNA gel electrophoresis showing overexpression of <i>TaLEA</i> in poplars.

<p>A: Detection of the transgene from kanamycin-resistant lines by RT-PCR; M: DNA molecular weight marker (DL2000), P: positive control (pROKII-<i>TaLEA</i>); N: negative control using water as PCR template; WT: negative control using DNA from WT plants as PCR template; T01-T14: independently transformed poplar lines. B: Analysis of transgene expression in transgenic lines by RNA gel blot analysis; WT: wild type plant; T01-T14: independently transformed poplar lines.</p

The effects of salt and drought stress on leaf wilting of transgenic and non-transgenic poplar plants.

<p>Histograms showing the percentage of wilted leaves in WT and <i>TaLEA</i>-transformed poplars under salt and drought stress. At least five plants from each line were used for biological repeats in each experiment. Values are means ± S.D. and the level of significance was set at <i>P</i> < 0.05. The stars above the bars indicate significant differences (<i>P</i> < 0.05) between the transgenic lines and WT under the test conditions.</p

Effects of stress on the relative rate of growth of WT and transgenic plants.

<p>Histograms showing a comparison in the rate of growth between WT and <i>TaLEA</i>-transformed poplars. A: Control condition; B: 200 mM NaCl treatment for 6 d; C: Withholding water for 7 d. At least five plants from each line were used for biological repeats in each experiment. Values are means ± S.D. and the level of significance was set at <i>P</i> < 0.05. The stars above the bars indicate significant differences (<i>P</i> < 0.05) between the transgenic lines compared with WT.</p

Hierarchically Structured and Scalable Artificial Muscles for Smart Textiles

Fiber-based artificial muscles with excellent actuation performance are gaining great attention as soft materials for flexible actuators; however, current advances in fiber-based artificial muscles generally suffer from high cost, harsh stimulation regimes, limiting deformations, chemical toxicity, or complex manufacturing processing, which hinder the widespread application of those artificial muscles in engineering and practical usage. Herein, a facile cross-scale processing strategy is presented to construct commercially available nontoxic viscose fibers into fast responsive and humidity-driven yarn artificial muscles with a recorded torsional stroke of 1752° cm–1 and a maximum rotation speed up to 2100 rpm, which are comparable to certain artificial muscles made from carbon-based composite materials. The underlying mechanism of such outstanding actuation performance that begins to form at a mesoscale is discussed by theoretical modeling and microstructure characterization. The as-prepared yarn artificial muscles are further scaled up to large-sized fabric muscles through topological weaving structures by integrating different textile technologies. These fabric muscles extend the simple motion of yarn muscles into higher-level diverse deformations without any composite system, complex synthetic processing, and component design, which enables the development of new fiber-based artificial muscles for versatile applications, such as smart textiles and intelligent systems

Hierarchically Structured and Scalable Artificial Muscles for Smart Textiles

Fiber-based artificial muscles with excellent actuation performance are gaining great attention as soft materials for flexible actuators; however, current advances in fiber-based artificial muscles generally suffer from high cost, harsh stimulation regimes, limiting deformations, chemical toxicity, or complex manufacturing processing, which hinder the widespread application of those artificial muscles in engineering and practical usage. Herein, a facile cross-scale processing strategy is presented to construct commercially available nontoxic viscose fibers into fast responsive and humidity-driven yarn artificial muscles with a recorded torsional stroke of 1752° cm–1 and a maximum rotation speed up to 2100 rpm, which are comparable to certain artificial muscles made from carbon-based composite materials. The underlying mechanism of such outstanding actuation performance that begins to form at a mesoscale is discussed by theoretical modeling and microstructure characterization. The as-prepared yarn artificial muscles are further scaled up to large-sized fabric muscles through topological weaving structures by integrating different textile technologies. These fabric muscles extend the simple motion of yarn muscles into higher-level diverse deformations without any composite system, complex synthetic processing, and component design, which enables the development of new fiber-based artificial muscles for versatile applications, such as smart textiles and intelligent systems

Hierarchically Structured and Scalable Artificial Muscles for Smart Textiles

Fiber-based artificial muscles with excellent actuation performance are gaining great attention as soft materials for flexible actuators; however, current advances in fiber-based artificial muscles generally suffer from high cost, harsh stimulation regimes, limiting deformations, chemical toxicity, or complex manufacturing processing, which hinder the widespread application of those artificial muscles in engineering and practical usage. Herein, a facile cross-scale processing strategy is presented to construct commercially available nontoxic viscose fibers into fast responsive and humidity-driven yarn artificial muscles with a recorded torsional stroke of 1752° cm–1 and a maximum rotation speed up to 2100 rpm, which are comparable to certain artificial muscles made from carbon-based composite materials. The underlying mechanism of such outstanding actuation performance that begins to form at a mesoscale is discussed by theoretical modeling and microstructure characterization. The as-prepared yarn artificial muscles are further scaled up to large-sized fabric muscles through topological weaving structures by integrating different textile technologies. These fabric muscles extend the simple motion of yarn muscles into higher-level diverse deformations without any composite system, complex synthetic processing, and component design, which enables the development of new fiber-based artificial muscles for versatile applications, such as smart textiles and intelligent systems