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Abstract Wide-field single-molecule tracking is often limited by the ~10 ms camera frame time. We introduce SpeedyTrack, which directly enables microsecond wide-field single-molecule tracking/imaging on common setups. Harnessing the native sub-microsecond vertical charge shifting capability of EM-CCDs, SpeedyTrack staggers wide-field single-molecule images along the CCD chip at ~10-row spacings between consecutive timepoints, effectively projecting the time domain to the spatial domain. Wide-field tracking is achieved for molecules diffusing at up to 1000 µm²/s at 50 µs temporal resolutions for >30 timepoints. Concurrent Förster resonance energy transfer measurements further elucidate molecular states. By implementing temporally patterned vertical shifting, VS-SpeedyTrack next deconvolves the spatial and temporal information to map trajectories at the super-resolution level, resolving the diffusion mode of a fluorescent protein in live cells with nanoscale resolution. Without modifications to existing optics or electronics, SpeedyTrack provides a facile solution to the microsecond tracking of single molecules and their super-resolution mapping in the wide field. 

Earthquakes on the Salt Lake City Segment of the Wasatch fault (WFSLC) represent the most significant seismic hazard to the Salt Lake Valley, populated by 1 million+ people. The 2020 Magna, UT, earthquake, which likely occurred on the WFSLC, generated peak ground accelerations (PGAs) as large as 0.55 gin the Salt Lake Valley. Here, we present three-dimensional (3D) physics-based wave propagation simulations of the Magna earthquake sequence in the Wasatch Front Community Velocity Model (WFCVM) up to 10 Hz to better constrain both linear and nonlinear parameters in the soils of the Salt Lake Valley. We first calibrate the WFCVM via linear simulations of a $M_w$ 4.59 Magna aftershock, obtaining the best fit between the recordings and synthetics, including a statistical distribution of small-scale heterogeneities with 10% standard deviation and $Q_S=0.05V_S$ for frequencies $<1$  Hz and $Q_S=0.05V_S{f}^{0.4}$ for frequencies $>1$  Hz ( $V_s$ in m/s). Spectral ratios from our simulations of the 2020 Magna mainshock using a finite-fault source model generally overestimate those for the recordings in the linear regime at higher frequencies, in particular at stations with the largest PGAs, suggesting the presence of nonlinear soil effects. Using a fully hysteretic multi-yield-surface 3D nonlinear modeling approach, we find that damping from the reference strain–depth relations proposed by Darendeli significantly reduces the bias in terms of spectral amplification ratios at stations with the shortest epicentral distances. We find an optimal fit between the recordings and nonlinear synthetics for reference strains at about 2 standard deviations below Darendeli’s relations, with reduction of the spectral amplification bias by more than a factor of two. Our findings suggest significant nonlinear soil effects in the Salt Lake Valley and provide a basis for improved seismic hazard analysis of the greater Salt Lake City region. 

Abstract In this study, we explore the operation and performance of electrolyte-gated junctionless III-V nanowire (NW) transistors featuring compositionally graded In_xGa_1-xAs channels. These devices leverage the electric double-layer (EDL) gating mechanism at the electrolyte/semiconductor interface to achieve ultra-high charge carrier densities, surpassing those possible with conventional oxide dielectrics. Fermi–Dirac statistics are introduced by a numerical method to reproduce associated charge densities of EDL transistors. A 1 nm interfacial HfO₂layer is introduced to capture the electrostatics of the EDL, prevent charge transfer between the electrolyte and the semiconductor, and mimic the Stern layer. Device simulations are conducted to optimize the heterostructured NW composition and doping profile, followed by benchmarking against traditional HfO₂-gated structures. The EDL-gated device achieves anI_ON/I_OFFratio of 10⁶, with a subthreshold slope of 60 mV/dec and a threshold voltage of 0.31 V at a low drain voltage of 0.3 V, indicating a two-order magnitude improvement over conventional junctionless oxide-gated NW transistors. Computational methodologies include finite element modeling in COMSOL to extract voltage-dependent ion densities and subsequent device simulations using Silvaco's Atlas software. The results indicate that the optimized EDL-gated device exhibits superior electrostatic integrity and performance metrics compared to conventional gating methods. The findings underscore the potential of EDL gating in III-V NW configurations for advanced electronic applications, demonstrating significant improvements in switching characteristics and power efficiency. Further optimization and exploration of bias-dependent ionic concentrations and configurable device geometries highlight the robustness and scalability of this approach for next-generation low-power electronics.