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This article presents the effects of different grounding strategies (ungrounded, direct grounded, and diode grounded), bonding, and insulation on rail potential and stray currents in the Taipei rapid transit systems (TRTSs). The TRTS is a direct current transit railway and its running rails are used as the return conductor for traction currents. The advantage is that no dedicated return conductor is required, whereas the disadvantages are rail potential and stray-current problems. Thus, the analysis of grounding strategies is important and necessary. Moreover, the effects of cross-bonding of the running rails and stray-current collector cables (traction earth conductors) are investigated since bonding is usually used to balance traction negative return currents, to reduce resistances of the negative return circuit, aswell as to decrease rail potential. Meanwhile, the effects of insulation on stray currents are also described. Simulation results for the Blue line are presented in TRTS. [ABSTRACT FROM AUTHOR]

A single- and multispectral-band diode end-pumped self-mode-locked Nd:YAP laser is originally demonstrated with an intracavity etalon to properly control the gain-to-loss ratios among the intermanifold lines on the 4F3/2  →  4I11/2 transition level. With a pulse repetition rate of 5.07 GHz, the shortest pulse durations under the single-spectral-band operation are achieved to be 11.1 ps at 1073 nm, 10.9 ps at 1080 nm, and 15.1 ps at 1084 nm, respectively. Moreover, the temporal overlapping of the multispectral-band pulses is experimentally found to lead to the generation of an intensity fringe pattern in the autocorrelation trace with the optical-beat frequency reaching several terahertz. A simple mathematical model is developed to elucidate the formation of a train of optical-beat pulses. [ABSTRACT FROM AUTHOR]