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Plane wave compounding is a useful mode for ultrasound imaging because it can make a good compromise between imaging quality and frame rate. It is also useful for broad view ultrasound imaging. Traditional coherent plane wave compounding coherently sums the echo data of different steered transmitting waves as the output. The data correlation information of different emissions is not considered. Therefore, some adaptive techniques can be introduced into the compounding procedure. In this paper, we propose a Joint Transmitting-Receiving (JTR) adaptive beamforming scheme for plane wave compounding. Unlike traditional adaptive beamformers, the proposed beamforming scheme is designed for the 2-D data set obtained from multiple plane wave firings. It calculates both the transmitting aperture weights and the receiving aperture weights and then combines them into a 2-D adaptive weight function for compounding. Experiments are conducted on both simulated and phantom data. Results show that the proposed scheme has better performance on both point targets and cysts than the existing plane wave compounding approach. Because of the adaptive process in both apertures for compounding, an improved resolution is observed in both simulation and phantom studies. When the eigenanalysis is introduced, a contrast enhancement is achieved. For the simulated cyst, a contrast ratio (CR) improvement of 48% is achieved compared with the traditional plane wave compounding. For the phantom cyst, this improvement is 213.8%. The proposed scheme also has good robustness against sound velocity errors. Therefore, it is effective in enhancing the coherent plane wave compounding quality.

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A series of phosphine oxide (PO) hosts based on diphenylphosphine oxide and spiro[fluorene-9,9 0 -xanthene] (SFX) moieties, SFX2PO, SFX27PO, SFX2 0 PO, and SFX2 0 7 0 PO, were designed and synthesized. On the basis of the different electrical properties of xanthene and fluorene in SFX, the influence of substitution position on the chemical and optophysical properties of the ambipolar-core based systems were investigated in detail. The effective strategy of introducing electron-withdrawing PO moieties in electron-deficient moieties in the molecules accompanied with suitable linkages insulating the electron-rich and -deficient moieties was convincingly demonstrated, which can endow the hosts with much better carrier injecting and transporting ability and high enough T 1 for blue and green phosphors. As the results, the operating voltages of the devices based on SFX2PO and SFX27PO were much lower than those of the devices based on SFX2 0 PO and SFX2 0 7 0 PO. Simultaneously, the efficiencies of the SFX2PO based devices were about twice of those of the devices based on SFX2 0 PO and SFX2 0 7 0 PO. We suppose that it is not necessary to achieve too high T1 and improved electron injection through PO moieties at the cost of sacrificing the hole injecting ability of the chromophores. An ideal strategy is preserving high enough T1 and improving electron injection by utilizing PO moieties without reducing hole injection and transportation in the hosts.