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High-power pulse generators are widely used in civil and military fields. The main switch directly determines the output characteristics of the high-power pulse generators, such as the voltage front time (t f). Pseudospark switches (PSS) show a promising future for middle voltage, high repetitive frequency pulse power applications. However, how to further improve the breakdown behavior without reducing its advantages is a challenging task. In this paper, the influence of operating parameters (anode voltage U A and gas pressure p) and structural parameter (number of cathode holes) on the breakdown behavior are investigated, the related mechanism are explained, and specific improvement schemes are proposed. It is found that the t f of the single channel PSS (SCPSS) decreased significantly with increasing p, but hardly varied with U A under moderate p. However, it is not a sound solution to increase the p excessively to reduce t f. Besides, increasing the number of cathode holes can obtain a shorter t f at low pressures (which implies superior repetition frequency performance). However, at 25 Pa, the jitter (which is defined as the standard deviation of t f in multiple tests) of the 2-channel PSS is larger than that of the SCPSS. And the jitter of the 4-channel and 8-channel PSS is also greater than 6 ns and 2 ns, respectively. Through experimental and simulation analyses, it can be explained as the stepwise penetration of the virtual anode and the non-simultaneous ignition of the channels. A scheme to increase the trigger energy (ϵ) has been adopted to improve the simultaneous ignition probability, while shortening t f and reducing jitter. After optimization, the good ignition probability of the 4-channel PSS has been improved to 82% and the jitter has been reduced to less than 1 ns at 25 Pa and 14.7 mJ. [ABSTRACT FROM AUTHOR]

The Blumlein pulse forming network (PFN) has widely been used in pulsed power technology to generate square waves with short pulse widths. In this paper, we developed a repetitive frequency square wave generator based on Blumlein PFN and pseudospark switch (PSS). A Blumlein PFN with unequal capacitances has been proposed, and the PFN parameters have been optimized for better output waveforms. A single-gap PSS with a withstand voltage of 40 kV and a repetitive frequency of 100 Hz has been designed to switch the Blumlein PFN. The experiment results show that the square wave generator can output pulses with a voltage of 26 kV, a rise time of 25 ns, and a pulse width of 90 ns on a matched load of 11 Ω. It has operated steadily for 10 h with a repetitive frequency of 100 Hz, and the jitter remains at around 1 ns after 1.05 × 106 shots. [ABSTRACT FROM AUTHOR]

The objective of this study was to provide a comprehensive assessment methodology for the quality control of Forsythia suspensa (FS). The peak purity was initially determined by dual-wavelength absorption coefficient ratio profiling (DACRP). Subsequently, to overcome the drawbacks of single-wavelength assessment, the fingerprint profiles of multiple wavelengths were fused and the UV and IR spectrum data of Forsythia suspensa were processed to create quantum fingerprint profiles, which were later evaluated by the method of quantitative comprehensive ratio fingerprint (MQCRF). An online antioxidant system and a partial least squares model were also used to establish fingerprint efficacy relationships, investigate the use of chromatographic peaks and the UV spectrum in antioxidant activity, and predict potential bioactive substances and their distribution wavelength ranges. Finally, the quality consistency of Forsythia suspensa was comprehensively described and evaluated. [ABSTRACT FROM AUTHOR]