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We developed a novel method of microwave irradiation to deal with Escherichia coli (E. coli), realized the trans-membrane and trans-wall direct electron transfer of Guanine in viable E. coli. Typical surface controlled irreversible electrode process of E. coli was achieved by cyclic voltammetry with the participating of two electrons and two protons. The method of bacterium culture and colony count showed that the direct electrochemistry of E. coli could be realized with its biological activity maintained. In addition, the electrochemical parameters of E. coli were further achieved, which provided a paradigm for direct electrochemical study of other bacteria.

This paper proposes a synchronized measurement method of analyzing collapsing granular piles using a high-speed camera and a grid-based tactile pressure sensor. The method is developed with a pressure sensor comprising 2016 individual sensels and a granular pile consisting of approximately 24,000 ceramsite spheres. Geometric, kinetic, and mechanical quantities (i.e., packing fraction ϕ, mean speed v ¯ , and pressure P) are simultaneously measured for a more detailed analysis of collapse processes. Collapses last for about 3.3τc where the characteristic time τ c = h 0 / g , h0 is the initial height of the granular pile, and g is acceleration due to gravity. The failure angle is measured as φf ≈ 51°. The relation between packing fraction and flow speed in μ(I) rheology, which is a previous theoretical predication, is validated in the experimental measurements of this work. Pressure distributions beneath the granular pile are recorded in time. Results show that the probability density function of the scaled contact pressure exhibits the power-law for small stresses, whilst a Gaussian distribution for large pressures beneath the granular pile at the initial state. As the pile is agitated, a large drop in pressure is observed during the stage when many particles fall freely, and pressure propagation is compared with mean speed.