Relaxor-lead titanate (PbTiO 3 ) crystals, which exhibit extremely high piezoelectricity, are believed to possess high electro-optic (EO) coefficients. However, the optical transparency of relaxor-PbTiO 3 crystals is severely reduced as a result of light scattering and reflection by domain walls, limiting electro-optic applications. Through synergistic design of a ferroelectric phase, crystal orientation, and poling technique, we successfully removed all light-scattering domain walls and achieved an extremely high transmittance of 99.6% in antireflection film–coated crystals, with an ultrahigh EO coefficient r 33 of 900 picometers per volt (pm V −1 ), >30 times as high as that of conventionally used EO crystals. Using these crystals, we fabricated ultracompact EO Q-switches that require very low driving voltages, with superior performance to that of commercial Q-switches. Development of these materials is important for the portability and low driving voltage of EO devices.

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Nonthermal plasma-catalysis hybrid technology (NTP-C) operated at ambient temperature and pressure offers an innovative and effective approach to solving the problem of dilute volatile organic compounds pollution. Herein, the destruction of benzene (50-450 ppm) over an in-plasma NTP-C composite system was investigated. The AO x /active carbon (AO x /AC), AO x /3A molecular sieve (AO x /MS), and AO x /c-Al 2 O 3 (A = Fe, Ag, Zn, Mn, and Cu) catalysts were prepared by the incipientwetness impregnation method. The destruction performances of NTP alone and NTP-C are compared under different reaction conditions, such as inlet reactant concentration, catalyst type, and energy density. AC exhibits the best benzene removal efficiency among three catalyst supports, and the performances of AO x /AC under different conditions follow the trend ofThe NTP with CuO/AC system exhibits the highest benzene elimination capability with almost 90.6 % inlet benzene removed at energy density of 70 and 270 J L -1 . The strong adsorption ability of AC and the optimal catalytic ability of crystalline structure of CuO on the AC support may be contributed to the excellent performance of CuO/AC. It is found that the NO x by-product also can be well controlled over NTP-CuO/AC system. Additionally, the surface of CuO/AC is more slipperier and homogeneous with the reaction proceeding, indicating higher stability of CuO/AC.

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Relaxor-based ferroelectric crystals of lead magnesium niobate-lead titanate (PMN-PT) are attracting great attention due to their prominent piezoelectric properties. Moreover, an enhancement of the integral properties requires the deep understanding of domain kinetics and domain structure evolution for application of the domain engineering techniques in relaxor-PT materials. Here, we demonstrate the results of studying the domain structure evolution by direct optical imaging during polarization reversal in [111]-oriented rhombohedral PMN-PT single crystals. Three domain types involved in the switching process have been revealed. The following consequent stages of the domain structure evolution have been separated: (I) nucleation and growth of a↑-domains and 2a-CDW and (II) nucleation and growth of c↓-domains. The undesirable effect of the partial backswitching during the electric field decrease was attributed to the clamped switching conditions.

Extensively studied PMN-PT and PIN-PMN-PT crystals with compositions close to the morphotropic phase boundary possess excellent piezoelectric characteristics. Recently developed alternating current treatment enhances the piezoelectric performance even further. Here, we demonstrate the results of studying the domain structure evolution by direct optical imaging during polarization reversal in [001]-oriented PIN-PMN-PT single crystals of rhombohedral phase during alternating current poling (ACP). The main types of domain structures involved in polarization reversal were revealed. Cross-like domain structure (CDS) was found to be undesirable for the piezoelectric application. The ACP-treatment proved to be effective in reducing the CDS fraction as a result of the growth of lens-shaped domains attributed to the 71° switching. The interaction of cross-like and lens-shaped domains was proposed as a key mechanism for improving the piezoelectric properties by the ACP-treatment. Comparison of the switching current with optical images revealed the correlation between the CDS area and electric field corresponding to the current maximum. This fact allows optimizing the number of the ACP-treatment pulses based on the switching current data without optical imaging.

& In order to eliminate the effects of flow regimes on phase concentration measurements, electrical capacitance tomography (ECT) was employed to improve the measurement accuracy. The solid particle distribution in the flow pipelines were characterized by measuring capacitance to obtain flow patterns. An improved offline iteration online reconstruction (OIOR) algorithm was proposed as the image reconstruction for the ECT system and a method of two-dimension maximum entropy threshold image segmentation was used for further image processing. Dynamic experiments were carried out for gas=solid two-phase flows. First, the flow regime was identified by the ECT, and the results were used to trace the fluctuation of the dynamic two-phase flow online. The volume concentrations were then calculated based on the reconstructed results. The experimental results indicate that the average relative error of the concentration measurements was about 1.5% over a pulverized coal volume concentration range 0.96-4.97%.