Spatio-temporal mapping of variation potentials in leaves of Helianthus annuus L. seedlings in situ using multi-electrode array.

Damaging thermal stimuli trigger long-lasting variation potentials (VPs) in higher plants. Owing to limitations in conventional plant electrophysiological recording techniques, recorded signals are composed of signals originating from all of the cells that are connected to an electrode. This limitation does not enable detailed spatio-temporal distributions of transmission and electrical activities in plants to be visualised. Multi-electrode array (MEA) enables the recording and imaging of dynamic spatio-temporal electrical activities in higher plants. Here, we used an 8 × 8 MEA with a polar distance of 450 μm to measure electrical activities from numerous cells simultaneously. The mapping of the data that were recorded from the MEA revealed the transfer mode of the thermally induced VPs in the leaves of Helianthus annuus L. seedlings in situ. These results suggest that MEA can enable recordings with high spatio-temporal resolution that facilitate the determination of the bioelectrical response mode of higher plants under stress

Characterization and activity of N doped TiO2 supported VPO catalysts for NO oxidation

AbstractNitrogen (N) doped TiO2 supported vanadium phosphorus oxide (VPO) catalysts were prepared and tested for catalytic oxidation of NO. The experimental results showed that 0.1V(5)PO/TiN(1) was the optimal catalyst for NO oxidation and the NO conversion could reach 61% at temperature of 350°C. The physico–chemical properties of 0.1V(5)PO/TiN(1) catalyst were characterized by Brunauer–Emmett–Teller measurements (BET), Photoluminescence (PL), X–ray photoelectron spectroscopy (XPS), Infrared spectroscopy measurements of NH3 adsorbed on catalysts (NH3–IR), and Infrared Fourier transform spectroscopy (FTIR). The PL and XPS spectra revealed that the oxygen storage capacity and catalytic activity of VPO/Ti catalyst can be improved by nitrogen doping. The H2–TPR profile also indicated that V(5)PO/TiN(1) catalyst had a superior redox property. Activity test results and FTIR spectra showed that 0.1V(5)PO/TiN(1) catalysts had a superior resistivity to SO2 and the NO oxidation rate is above 50% at temperature of 350°C when SO2 concentration is 200ppm to 800ppm

Efficiency of electrochemical chloride removal from concrete at different environmental temperatures

Electrochemical chloride removal (ECR) is an effective and curative method to treat existed reinforced concrete structures about to suffer or already suffering from chloride attack, however, its application is still limited due to its side effect and efficiency, including the velocity and maximum capacity of chloride removal. This paper presents a temperature related numerical transport model to study the effect of temperature on efficiency of electrochemical chloride removal from concrete. Based on Fick’s law and Nernst-Planck equation with Gauss’ Law, temperature effect, chloride binding, multi-species coupling, electrochemical reactions were taken into account in this model. Temperature effect was considered on diffusion coefficient, chloride binding, ions migration capacity as well as electrolyte concentration. The model was validated by the comparison between the calculated results and experimental data. The results indicate that temperature dose have a considerable influence on electrochemical chloride removal and controlling temperature during treatment is a practical method to improve the electrochemical chloride removal when applied current density is not amplified

Flavonoids from Saussurea stella Maxim as superoxide scavengers and antioxidants

1201-120

Generation of high-density high-polarization positrons via single-shot strong laser-foil interaction

We put forward a novel method for producing ultrarelativistic high-density high-polarization positrons through a single-shot interaction of a strong laser with a tilted solid foil. In our method, the driving laser ionizes the target, and the emitted electrons are accelerated and subsequently generate abundant $\gamma$ photons via the nonlinear Compton scattering, dominated by the laser. These $\gamma$ photons then generate polarized positrons via the nonlinear Breit-Wheeler process, dominated by a strong self-generated quasi-static magnetic field $\mathbf{B}^{\rm S}$. We find that placing the foil at an appropriate angle can result in a directional orientation of $\mathbf{B}^{\rm S}$, thereby polarizing positrons. Manipulating the laser polarization direction can control the angle between the $\gamma$ photon polarization and $\mathbf{B}^{\rm S}$, significantly enhancing the positron polarization degree. Our spin-resolved quantum electrodynamics particle-in-cell simulations demonstrate that employing a laser with a peak intensity of about $10^{23}$ W/cm$^2$ can obtain dense ($\gtrsim$ 10$^{18}$ cm$^{-3}$) polarized positrons with an average polarization degree of about 70\% and a yield of above 0.1 nC per shot. Moreover, our method is feasible using currently available or upcoming laser facilities and robust with respect to the laser and target parameters. Such high-density high-polarization positrons hold great significance in laboratory astrophysics, high-energy physics and new physics beyond the Standard Model