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Free-space optical (FSO) communication has received widespread attention as a high-bandwidth, low-latency communication technique. However, the scintillation effect caused by atmospheric turbulence leads to intensity fluctuations of the transmission signal, which, in turn, affects the performance of the FSO communication system. This paper proposes a channel correlation-based adaptive power transmission for FSO communications. Based on the correlation between uplink and downlink turbulence channels, the power of the reverse transmission signal is adjusted by the fluctuation strength of the received uplink or downlink transmission signal and the channel correlation coefficient to improve the system's performance. The proposed technique is investigated through a simulation using established uplink and downlink channels with different link distances and turbulence intensities. The simulation results show that the bit error rate (BER) performance of the proposed technique is significantly improved compared to the fixed threshold decision (FTD) technique, and it is close to the adaptive threshold decision (ATD) technique. The proposed technique provides an effective optimization scheme for FSO communications. [ABSTRACT FROM AUTHOR]

This paper studies a novel self-pilot tone based adaptive threshold return-to-zero on-off keying (RZ-OOK) decision for free-space optical (FSO) communications. RZ-OOK has the characteristics of impulse series in the spectrum. Therefore, these impulses can be utilized as the pilot tones of the transmitted signal to convey the channel state information (CSI) of FSO links. Then, the CSI signal is extracted using a local oscillator (LO) with the frequencies of the impulse series and low pass filter. Finally, the adaptive threshold decision (ATD) is realized by assigning optimized weight factors into the extracted CSI signal. The proposed adaptive threshold RZ-OOK decision was studied in simulation under various pulse durations of RZ-OOK signal and frequencies of LO. Simulation results demonstrated that RZ-OOK with the proposed impulse tone-extracted CSI signal under optimized weight factor performs close to the conventional ATD under precise CSI knowledge. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the estrogenic activity of several kinds of Chinese herbal medicines., Method: Use zoopery and reporter gene technique to study the estrogenic activity of five Chinese herbal medicines. Zoopery: weanling female Kunming mice weight 9-12 g were administrated botanical extracts of Selaginella tamariscina, Pinus Massoniana, Corallodiscus flabellate, Dryopteris sublaeta and Leonurus heterophyllus, the positive control group with Nilestriol tablets and control group with water, respectiely. On the eighth day, the animals were sacrificed and the uteri were separated solely and weighed. Reporter gene technique: Induce the expression of reporter gene controlled by ERE and measure the activity of luciferase on cell's clear supernatant., Result: The botanical extracts of S. tamariscina can increase weights of mice (P < 0.01); In the expression of reporter gene controlled by ERE, Either ERalpha or ERbeta's has estrogenic activity (P < 0.01). Follow in the zoopery we find the water part and the n-butanol part of S. tamariscina are the two active parts., Conclusion: S. tamariscina and it's water part and n-butanol part have estrogenic activities, effect on ERbeta is greater than ERalpha.