The photostability of Au nanorods in human hepatocellular carcinoma cells under two-photon excitation was investigated to evaluate their potential in cell imaging. The photoluminescence images of the intracellular Au nanorods under the two-photon excitation of an 800 nm femtosecond laser were photobleached rapidly, which is due to the melting of Au nanorods. The images lost their brightness for more than 50% after 15 micrograph scans for the nanorod incubation concentrations of 10, 20, and 40 pM. The confocal reflectance image can prevent the image photobleaching and thus is suitable for long-term cell imaging with Au nanorods.
The bandwidth covered by contemporary communication technologies has reached over an octave. But most existing power amplifier (PA) configurations cannot meet this requirement while at the same time maintaining a high efficiency. Therefore, a novel structure for bandwidth enhancement at a high efficiency level is proposed together with the systematic design methodology in this article. The difficulty lies in the overlap of the fundamental and harmonic frequencies. On this issue, the extended continuous Class‐B/J mode can extend the impedance of the second harmonic to a resistive‐reactive and relax design requirements for overlapping design space of fundamental and second harmonic frequencies. Specifically, the presented innovative circuit structure uses the multiple frequencies matching method to manipulate four fundamental and the corresponding second harmonics frequency points simultaneously, which can further effectively expand the bandwidth on the basis of the extended continuous Class‐B/J PA. To verify the validity of the proposed theory, a gallium nitride multioctave PA is designed, implemented, and measured. Measured results show a fractional bandwidth of 148.4% from 0.4 to 2.7 GHz, with drain efficiency of 63%‐78%, saturated output power greater than 39 dBm, and large signal gain larger than 9 dB. For the single carrier WCDMA signal with a channel bandwidth of 3.84 MHz and a peak to average power ratio of 6 dB, the adjacent channel power ratio of −47.5 to −35 dBc and −42.8 to −31.5 dBc at an average output power of 33 and 36 dBm separately are achieved over the whole frequency band.
In this paper, we present a 55" UHD AMOLED TV developed at G8.5 using IGZO backplane and tandem white-OLED with COA (color filter on array), which is considered as one of the feasible options for mass production. We also implement the external optical compensation to achieve good display uniformity.
A novel methodology for designing broadband high-efficiency power amplifiers (PAs) based on the harmonic-tuned is presented in this letter. All harmonics can be effectively manipulated by the innovative structure to achieve high-efficiency and the dual frequencies point harmonic matching method is also applied to the harmonic control network, which has a positive effect on the expansion bandwidth. To verify the validity of the proposed methodology, a gallium nitride PA is designed, implemented, and measured. Measured results manifest a wide bandwidth from 1.1 to 2.5 GHz, with drain efficiency (DE) of 67-86%, saturated output power greater than 39.5 dBm, and large signal gain larger than 9.5 dB. The in-band second and third harmonic suppression levels are maintained at −13 to −36 dBc and −23 to −44 dBc, respectively. Measurement results confirm the theoretical findings reported in this paper.
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