Nanopore sensing-based technologies have made significant progress for single molecule and single nanoparticle detection and analysis. In recent years, multimode sensing by multifunctional nanopores shows the potential to greatly improve the sensitivity and selectivity of traditional resistive-pulse sensing methods. In this paper, we showed that two label-free electric sensing modes could work cooperatively to detect the motion of 40 nm diameter spherical gold nanoparticles (GNPs) in solution by a multifunctional nanopipette. The multifunctional nanopipettes containing both nanopore and nanoelectrode (pyrolytic carbon) at the tip were fabricated quickly and cheaply. We demonstrated that the ionic current and local electrical potential changes could be detected simultaneously during the translocation of individual GNPs. We also showed that the nanopore/CNE tip geometry enabled the CNE not only to detect the translocation of single GNP but also to collectively detect several GNPs outside the nanopore entrance. The dynamic accumulation of GNPs near the nanopore entrance resulted in no detectable current changes, but was detected by the potential changes at the CNE. We revealed the motions of GNPs both outside and inside the nanopore, individually and collectively, with the combination of ionic current and potential measurements.

Revealing the electronic structure of organic emitting molecules is instructive for tuning electron-hole balance, one of the key factors in regulating the organic light emitting diodes (OLED) performance. Herein, we...

The release of valuable minerals from the associated gangues is called liberation. Good liberation is essential to the subsequent separation stage. Selective liberation is advantageous to improve the degree of liberation. Oolitic hematite is one of the typical refractory iron ores in China, and its resources are abundant. However, owing to its fine dissemination and complex mineralogical texture, the conventional grinding processes are inefficient in improving the selective liberation of oolitic hematite. In this study, microwave processing and acid leaching were used to assist the liberation of oolitic hematite. The assisted liberation of the oolitic hematite mechanisms of microwave processing and acid leaching were studied by using scanning electron microscope (SEM), X-ray diffraction (XRD), BET specific surface area detection method (BET) and the transflective microscope method. The results indicated that microwave processing can reduce the mechanical strength of oolitic hematite and improve the liberation of hematite, and acid leaching can improve the microwave-assisted liberation efficiency and reduce the content of phosphorus in the grinding product. Compared to direct grinding, the liberation of hematite increased by 54.80% in the grinding product, and especially, the fractions of −0.038-mm and 0.05-0.074 mm increased significantly; however, there was no obvious change in other grain sizes, and the dephosphorization ratio reached 47.20% after microwave processing and acid leaching. After the two stages, the iron grade and recovery of the magnetic separation product increased by 14.26% and 34.62%, respectively, and the dephosphorization ratio reached 88.59%. It is demonstrated that microwave processing and acid leaching comprise an efficient method to improve the liberation of hematite and the dephosphorization ratio of oolitic hematite. The two-stage treatment can achieve selective liberation of oolitic hematite, which is beneficial to the following magnetic separation.

As a sub-group of solid-state nanopore, nanopipette shows great potential to develop into a platform for efficient and rapid DNA detection.