8 research outputs found

    Air-Stable, High-Performance, Flexible Microsupercapacitor with Patterned Ionogel Electrolyte

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    We describe the fabrication of air-stable, high-performance, planar microsupercapacitors (MSCs) on a flexible poly­(ethylene terephthalate) substrate with patterned ionogel electrolyte, i.e., poly­(ethylene glycol) diacrylate/1-ethyl-3-methylimidazolium bis­(trifluoromethylsulfonyl)­imide, and electrodes of spray-coated multiwalled carbon nanotubes. The flexible MSC showed good cyclability, retaining ∼80% of initial capacitance after 30 000 cycles, and good mechanical stability down to a bending diameter of 3 mm under compressive stress; 95% of the initial capacitance was retained after 1000 bending cycles. The MSC had high electrochemical stability with retaining 90% of its initial capacitance for 8 weeks in air. Furthermore, vertical stacking of MSCs with patterned solid film of ionogel electrolyte could increase the areal capacitance dramatically. This flexible MSC has potential applications as an energy-storage device in micro/nanoelectronics, without encapsulation for air stability

    Image_1_Extracellular self-RNA: A danger elicitor in pepper induces immunity against bacterial and viral pathogens in the field.TIF

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    Plants and animals serve as hosts for microbes. To protect themselves from microbe-induced damage, plants and animals need to differentiate self-molecules/signals from non-self, microbe-derived molecules. Damage-associated molecular patterns (DAMPs) are danger signals released from the damaged host tissue or present on the surface of stressed cells. Although a self-extracellular DNA has previously been shown to act as a DAMP in different plant species, the existence of a self-extracellular RNA (eRNA) as a danger signal in plants remains unknown. Here, we firstly evaluated the ability of a pepper self-eRNA to activate immunity against viral and bacterial pathogens under field conditions. Pepper leaves pre-infiltrated with self-eRNA exhibited reduced titer of the naturally occurring Tomato spotted wilt virus and diminished symptoms of Xanthomonas axonopodis pv. vesicatoria infection through eliciting defense priming of abscisic acid signaling. At the end of the growing season at 90 days after transplanting, pepper plants treated with self- and non-self-eRNAs showed no difference in fruit yield. Taken together, our discovery demonstrated that self-eRNA can successfully activate plant systemic immunity without any growth penalty, indicating its potential as a novel disease management agent against a broad range of pathogenic microbes.</p

    Selective Suppression of Stimulated Raman Scattering with Another Competing Stimulated Raman Scattering

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    A three-beam femtosecond stimulated Raman scattering (SRS) scheme is formulated and demonstrated to simultaneously induce two different SRS processes associated with Raman-active modes in the same molecule. Two SR gains involving a common pump pulse are coupled and compete: As one of the Stokes beam intensities increases, the other SRS is selectively suppressed. We provide theoretical description and experimental evidence that the selective suppression behavior is due to the limited number of pump photons used for both of the two SRS processes when an intense depletion beam induces one SRS process. The maximum suppression efficiency was ∼60% with our experimental setup, where the SR gain of the ring breathing mode of benzene is the target SRS signal, which is allowed to compete with another SRS process, induced by an intense depletion beam, of the CH stretching mode. We anticipate a potential of this new switching-off concept in super-resolution label-free microscopy

    Strain Mapping and Raman Spectroscopy of Bent GaP and GaAs Nanowires

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    Strain engineering of nanowires (NWs) has been recognized as a powerful strategy for tuning the optical and electronic properties of nanoscale semiconductors. Therefore, the characterization of the strains with nanometer-scale spatial resolution is of great importance for various promising applications. In the present work, we synthesized single-crystalline zinc blende phase GaP and GaAs NWs using the chemical vapor transport method and visualized their bending strains (up to 3%) with high precision using the nanobeam electron diffraction technique. The strain mapping at all crystallographic axes revealed that (i) maximum strain exists along the growth direction ([111]) with the tensile and compressive strains at the outer and inner parts, respectively; (ii) the opposite strains appeared along the perpendicular direction ([2̅11]); and (iii) the tensile strain was larger than the coexisting compressive strain at all axes. The Raman spectrum collected for individual bent NWs showed the peak broadening and red shift of the transverse optical modes that were well-correlated with the strain maps. These results are consistent with the larger mechanical modulus of GaP than that of GaAs. Our work provides new insight into the bending strain of III–V semiconductors, which is of paramount importance in the performance of flexible or bendable electronics

    Non-Heme Manganese Catalysts for On-Demand Production of Chlorine Dioxide in Water and Under Mild Conditions

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    Two non-heme manganese complexes are used in the catalytic formation of chlorine dioxide from chlorite under ambient temperature at pH 5.00. The catalysts afford up to 1000 turnovers per hour and remain highly active in subsequent additions of chlorite. Kinetic and spectroscopic studies revealed a Mn<sup>III</sup>(OH) species as the dominant form under catalytic conditions. A Mn<sup>III</sup>(μ-O)­Mn<sup>IV</sup> dinuclear species was observed by EPR spectroscopy, supporting the involvement of a putative Mn<sup>IV</sup>(O) species. First-order kinetic dependence on the manganese catalyst precludes the dinuclear species as the active form of the catalyst. Quantitative kinetic modeling enabled the deduction of a mechanism that accounts for all experimental observations. The chlorine dioxide producing cycle involves formation of a putative Mn<sup>IV</sup>(O), which undergoes PCET (proton coupled electron-transfer) reaction with chlorite to afford chlorine dioxide. The ClO<sub>2</sub> product can be efficiently removed from the aqueous reaction mixture via purging with an inert gas, allowing for the preparation of pure chlorine dioxide for on-site use and further production of chlorine dioxide
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