In process analytical chemistry, mass spectrometry analysis using a soft electron ionization (EI) source has qualitative advantages. However, the relatively small ionization cross-section of soft EI leads to lower sensitivity. To address this issue, a novel method has been developed to enhance the sensitivity of soft EI by utilizing a dual electron repeller and an ionization chamber to form a U-shaped electric field, causing electrons to oscillate within the field and effectively increasing the electron collision cross-sectional area. By combining with an electron lens, the virtual cathode effect at low electron energy can be reduced or even eliminated, thereby improving ionization efficiency. This method has resulted in a significant increase in signal intensity for m/z 18(H₂O), with a factor of 4.2 at an electron energy of 25 eV and a factor of 3.75 at 20 eV, compared to the electron receiving mode. Additionally, it reduces the required emission current, which is beneficial for prolonging the life of the filament. The proposed technique is expected to expand the application of soft EI, particularly for rapid online analysis in process analytical chemistry such as catalyst research and chemical reaction process monitoring.

This article proposes and examines a solution in which the base-station for the fifth generation radio access network is simplified by using a single millimeter-wave oscillator in the central-station and distributing its millimeter-wave signal to the base-stations. The system is designed in such a way that the low-phase-noise signal generated by an opto-electronic oscillator is transmitted from the central-station to multiple base-stations via a passive optical network infrastructure. A novel flexible approach with a single-loop opto-electronic oscillator at the transmitting end and a tunable dispersion-compensation module at the receiving end(s) is proposed to distribute a power-penalty-free millimeter-wave signal in the radio access network. Power-penalty-free signal transmission from 10 MHz up to 45 GHz with an optical length of 20 km is achieved by a combination of a tunable dispersion-compensation module and an optical delay line. In addition, measurements with a fixed modulation frequency of 39 GHz and discretely incrementing optical fiber lengths from 0.625 km to 20 km are shown. Finally, a preliminary idea for an automatically controlled feedback-loop tuning system is proposed as a further research entry point.