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It is quite necessary to develop a safe and efficient technique for disinfection of drinking water to avoid waterborne pathogens of infectious diseases. Herein, ZnO nanoarray electrodes with different sizes were investigated for low-voltage and high-efficiency electroporation disinfection. The results indicated that the ZnO nano-pyramid with small tip width and proper length exhibited over 99.9% disinfection efficiency against Escherichia coli under 1 V and a flow rate of 10 mL/min (contact time of 1.2 s). The suitable size of the nanoarray for electroporation disinfection was optimized by establishing the correlation between four kinds of ZnO nanoarrays and their efficiency of electroporation disinfection, which can guide the preparation of next-generation electroporation-disinfecting electrodes.

In this article, the flower-like, urchin-like, and rod-like ZnOs were synthesized by a convenient atmospheric hydrothermal method. The crystalline structures, morphologies, exposed crystal faces, and specific surface areas of the as-prepared ZnO samples were analyzed. Rhodamine B (RhB) was used as the simulated pollutant to evaluate the photocatalytic performance of the ZnO nanostructures. The flower-like ZnO prepared by controlled hydrothermal method at room temperature for 2 h displayed highest specific surface area and exposed more high active {21¯1¯0}\{2\bar{1}\bar{1}0\} facets compared to the other two morphologies of ZnO. In addition, within 2 h of the photocatalytic reaction, the flower-like ZnO results in 99.3% degradation of RhB and produces the most hydroxyl radicals (˙OH) 47.83 μmol/g and superoxide anions (˙O2−{\text{O}}_{2}^{-}) 102.78 μmol/g. Due to the existence of oxygen vacancies on the surface of {21¯1¯0}\{2\bar{1}\bar{1}0\} facets, the flower-like ZnO can efficiently catalyze the production of active oxygen, leading to the improvement in the photocatalytic efficiency.

The hyperfine transition of 3He+ at 3.5 cm has been thought as a probe of the high- z IGM, since it offers a unique insight into the evolution of the helium component of the gas, as well as potentially give an independent constraint on the 21 cm signal from neutral hydrogen. In this paper, we use radiative transfer simulations of reionization driven by sources such as stars, X-ray binaries, accreting black holes and shock heated interstellar medium, and simulations of a high- z quasar to characterize the signal and analyse its prospects of detection. We find that the peak of the signal lies in the range ∼1–50  μ K for both environments, but while around the quasar it is always in emission, in the case of cosmic reionization a brief period of absorption is expected. As the evolution of He  ii is determined by stars, we find that it is not possible to distinguish reionization histories driven by more energetic sources. On the other hand, while a bright QSO produces a signal in 21 cm that is very similar to the one from a large collection of galaxies, its signature in 3.5 cm is very peculiar and could be a powerful probe to identify the presence of the QSO. We analyse the prospects of the signal's detectability using SKA1-mid as our reference telescope. We find that the noise power spectrum dominates over the power spectrum of the signal, although a modest signal-to-noise ratio can be obtained when the wavenumber bin width and the survey volume are sufficiently large. [ABSTRACT FROM AUTHOR]

The hyperfine transition of 3He+ at 3.5 cm has been thought as a probe of the high- z IGM, since it offers a unique insight into the evolution of the helium component of the gas, as well as potentially give an independent constraint on the 21 cm signal from neutral hydrogen. In this paper, we use radiative transfer simulations of reionization driven by sources such as stars, X-ray binaries, accreting black holes and shock heated interstellar medium, and simulations of a high- z quasar to characterize the signal and analyse its prospects of detection. We find that the peak of the signal lies in the range ∼1–50  μ K for both environments, but while around the quasar it is always in emission, in the case of cosmic reionization a brief period of absorption is expected. As the evolution of He  ii is determined by stars, we find that it is not possible to distinguish reionization histories driven by more energetic sources. On the other hand, while a bright QSO produces a signal in 21 cm that is very similar to the one from a large collection of galaxies, its signature in 3.5 cm is very peculiar and could be a powerful probe to identify the presence of the QSO. We analyse the prospects of the signal's detectability using SKA1-mid as our reference telescope. We find that the noise power spectrum dominates over the power spectrum of the signal, although a modest signal-to-noise ratio can be obtained when the wavenumber bin width and the survey volume are sufficiently large. [ABSTRACT FROM AUTHOR]

Over the last years, extracting the empirical Green's functions (EGFs) from ambient seismic noise to obtain surface wave dispersion has become a well-established method in seismology. The EGFs derived from the vertical components of ambient seismic noise data include the fundamental-mode and higher-mode Rayleigh waves. Higher-mode Rayleigh waves can penetrate into deeper structure than the fundamental-mode ones. Considering the fundamental-mode and higher-mode Rayleigh waves simultaneously can greatly increase the constraint on shear velocity structure. The vector wavenumber transform method (VWTM) and the sensitivity analysis of dispersion curves of Rayleigh waves are two new approaches proposed by our group; the former can extract the dispersion imaging of the fundamental-mode and higher-modes of Rayleigh waves well from continuous ambient seismic noise data and the latter can be used to analyze the sensitivities of the fundamental-mode and higher-mode Rayleigh waves in depth and frequency.In this study, we apply the VWTM to the ambient seismic noise data from some temporary and permanent stations in the northwest of Bohemian massif and adjacent areas to obtain the dispersion curves of fundamental-mode and higher-mode Rayleigh waves. Then, we perform an inversion based on the dispersion curves to obtain the one-dimensional shear velocity models and show the differences of inversion models between two different situations. One is to utilize only the fundamental-mode Rayleigh waves, the other is to use both of fundamental-mode and higher-mode Rayleigh waves. After that, with the aid of sensitivity analysis of dispersion curves, we analyze the sensitivities of fundamental-mode and higher-mode Rayleigh waves in different depths and frequencies. At the last, based on the above analysis and comparison, we derive 1-D shear wave velocity models in the northwest of Bohemian massif and adjacent areas. [ABSTRACT FROM AUTHOR]