Abstract: A preparation method of perovskite film based on semicarbazide hydrochloride (SEM-HCl) additive and a preparation method of photovoltaic device are provided, a perovskite optimized crystallization strategy is provided, a tin-based perovskite thin film is prepared based on a solution method, and a purpose of regulating and controlling perovskite crystallization is achieved by means of a cross-linking effect of special groups in SEM-HCl and perovskite components. Defects of crystals of the prepared perovskite film are reduced, the non-radiative recombination in a transmission process of carriers is suppressed, and a photoelectric conversion efficiency and a photovoltaic device stability are remarkably improved.

Abstract: The present application is directed to a mounting system for a base station antenna. The system includes a passive antenna and an active antenna module and a mounting kit. The mounting kit includes an upper radio mounting bracket assembly and a lower radio mounting bracket assembly, and is configured to mount and secure an upper portion of the passive antenna to a mounting structure and mount and secure the active antenna module to the mounting structure behind the passive antenna. The system further includes a middle antenna mounting bracket assembly configured to pivotably mount a middle portion of the passive antenna to the mounting structure and a lower antenna mounting bracket assembly configured to slidably and/or pivotably mount a lower portion of the passive antenna to the mounting structure. The mounting system is configured to adjust the base station antenna downwardly or upwardly to a desired angle of tilt. Mounting kits and methods of operating same are also described herein.

Abstract: A preparation method of perovskite film based on semicarbazide hydrochloride (SEM-HCl) additive and a preparation method of photovoltaic device are provided, a perovskite optimized crystallization strategy is provided, a tin-based perovskite thin film is prepared based on a solution method, and a purpose of regulating and controlling perovskite crystallization is achieved by means of a cross-linking effect of special groups in SEM-HCl and perovskite components. Defects of crystals of the prepared perovskite film are reduced, the non-radiative recombination in a transmission process of carriers is suppressed, and a photoelectric conversion efficiency and a photovoltaic device stability are remarkably improved.

Abstract: A multichannel constant current LED driving circuit can include: (i) a power stage circuit having a power switching transistor, an inductor, and a rectifier circuit, where the power stage circuit is configured to receive a DC bus voltage, and to generate a pseudo-constant output signal to drive a plurality of LED strings; (ii) a current control unit configured to control an average current of each of the plurality of LED strings in accordance with a corresponding one of a plurality of dimming signals; and (iii) the current control unit being configured to control the power switching transistor in accordance with a current feedback signal that represents a current flowing through the LED strings, where the plurality of LED strings are coupled in series to receive the pseudo-constant output signal.

Abstract: A multichannel constant current LED driving circuit can include: (i) a power stage circuit having a power switching transistor, an inductor, and a rectifier circuit, where the power stage circuit is configured to receive a DC bus voltage, and to generate a pseudo-constant output signal to drive a plurality of LED strings; (ii) a current control unit configured to control an average current of each of the plurality of LED strings in accordance with a corresponding one of a plurality of dimming signals; and (iii) the current control unit being configured to control the power switching transistor in accordance with a current feedback signal that represents a current flowing through the LED strings, where the plurality of LED strings are coupled in series to receive the pseudo-constant output signal.

Abstract: A multichannel constant current LED driving circuit can include: (i) a power stage circuit having a power switching transistor, an inductor, and a rectifier circuit, where the power stage circuit is configured to receive a DC bus voltage, and to generate a pseudo-constant output signal to drive a plurality of LED strings; (ii) a current control unit configured to control an average current of each of the plurality of LED strings in accordance with a corresponding one of a plurality of dimming signals; and (iii) the current control unit being configured to control the power switching transistor in accordance with a current feedback signal that represents a current flowing through the LED strings, where the plurality of LED strings are coupled in series to receive the pseudo-constant output signal.

Abstract: A multichannel constant current LED driving circuit can include: (i) a power stage circuit having a power switching transistor, an inductor, and a rectifier circuit, where the power stage circuit is configured to receive a DC bus voltage, and to generate a pseudo-constant output signal to drive a plurality of LED strings; (ii) a current control unit configured to control an average current of each of the plurality of LED strings in accordance with a corresponding one of a plurality of dimming signals; and (iii) the current control unit being configured to control the power switching transistor in accordance with a current feedback signal that represents a current flowing through the LED strings, where the plurality of LED strings are coupled in series to receive the pseudo-constant output signal.