激光在高压测量中的应用

利用激光、电光学效应 ,克尔效应 (二次光学效应 )测量电场的分布 ,可以在几乎不改变被测电场分布的情况下 ,测出克尔效应物质所在点电场强度。据此研制的以硝基苯液体代替 Pockels晶体的激光—克尔效应高压电场测量系统 ,可用于工频冲击和直流场强的测量。

Piezopotential augmented photo-and photoelectro-catalysis with a built-in electric field

Rapid technological development and population growth are responsible for a series of imminent environmental problems and an ineluctable energy crisis.The application of semiconductor nanomaterials in photocatalysis or photoelectrocatalysis(PEC)for either the degradation of contaminants in the environment or the generation of hydrogen as clean fuel is an effective approach to alleviate these problems.However,the efficiency of such processes remains suboptimal for real applications.Reasonable construction of a built-in electric field is considered to efficiently enhance carrier separation and reduce carrier recombination to improve catalytic performance.In the past decade,as a new method to enhance the built-in electric field,the piezoelectric effect from piezoelectric materials has been extensively studied.In this review,we provide an overview of the properties of piezoelectric materials and the mechanisms of piezoelectricity and ferroelectricity for a built-in electric field.Then,piezoelectric and ferroelectric polarization regulated built-in electric fields that mediate catalysis are discussed.Furthermore,the applications of piezoelectric semiconductor materials are also highlighted,including degradation of pollutants,bacteria disinfection,water splitting for H2 generation,and organic synthesis.We conclude by discussing the challenges in the field and the exciting opportunities to further improve piezo-catalytic efficiency.

Influence of the Kerr Effect on the Optical Force Acting on the Dielectric Particle

Basing on the necessary condition for the trapping dielectric particle by the Gaussian beam, the Kerr effect in the tweezers with the nonlinear particle or the nonlinear medium is proposed to concern. The expressions of the optical forces concerned with the Kerr effect, which affects the refractive index of the medium, are presented. The distribution of the optical forces in the trapping region is simulated and discussed. The results show that the stability of the tweezers depends on the nonlinear coefficient of refractive index, and the optical tweezers could be broken down with a critical value of the nonlinear coefficient of refractive index of the surrounding medium, or with a critical value of the laser intensity, duration of laser pulse, and radius of beam waist. Moreover, these results give us the explanation the stability of the optical tweezers used for the trapped object as biological molecule embedded in the fluid, which is sensitive with Kerr effect.

Effect of growth time on morphology and photoelectrochemical performance of TiO_2 nanorod arrays grown on transparent conducting substrates

TiO_2 nanorod arrays(NRAs) were synthesized directly on the fluorine tin oxide(FTO) coated glass substrates by a facile hydrothermal route.The effects of growth time on the photoelectrochemical(PEC) properties of TiO_2 NRAs are investigated.The samples synthesized for 4 h exhibit a photocurrent intensity of 0.37 mA/cm^2 at the irradiation of Xe lamp and a bias of 0 V.As the growth time increases,the thickness and order degree of the NRAs are enhanced,but the photocurrent is reduced a lot.It might be associated with the hindering of a high background electron density in NRs due to the long-time hydrothermal reaction in acid environment.Moreover,the decline behavior is observed,which is attributed to the poor charge separation capacity of TiO_2 array electrodes and could be suppressed efficiently by applying a suitable positive bias.