Reducing children's exposure to traffic-related noise and air pollution in urban areas is a critical challenge. Therefore, evaluating traffic management strategies in a computational environment offers a practical tool for planners, policymakers, and researchers. However, a key research gap remains: most studies evaluate traffic strategies on air pollution, noise, or traffic separately. Few quantify their combined impacts in a single framework. To address this, we propose a multi-criteria evaluation approach and apply it by comparing four scenarios against a baseline. Through a comprehensive panel of statistical, spatial, and temporal analyses of traffic conditions, air pollutant concentrations, and noise levels, we find that: (1) restricting vehicle access during student arrival times significantly reduces exposure to both noise and air pollution; and (2) speed limit reductions have only limited effects on noise and may, under certain conditions, increase air pollution levels.

Optical control of lattice dynamics with high spatiotemporal precision offers a route to manipulate local quantum states—such as magnetic, spin, and topological states—by exploiting the coupling between the lattice and other degrees of freedom. Here, deterministic strain engineering is demonstrated with spatial and temporal characteristics in van der Waals materials using spatially structured femtosecond optical fields. By confining structural oscillations at a submicron scale, phonon cavities with programmable dimensions, oscillation periods, and symmetries are engineered. Through ultrafast electron microscopy analysis and finite-element simulations the dominant cavity modes, out-of-plane confined oscillations, and in-plane Lamb waves are directly imaged and identified. It is shown that the properties of these phonon cavities are programmable via the spatial profile of the optical excitation, enabling localized modulation of strain and lattice displacement at nanometer and picosecond scales. This work establishes a general framework for spatiotemporal phonon engineering, bridging structured light excitation with atomic-scale control of lattice dynamics.

Surface plasmons offer a promising avenue in the pursuit of swift and localized manipulation of magnetism for advanced magnetic storage and information processing technology. However, observing and understanding spatiotemporal interactions between surface plasmons and spins remains challenging, hindering optimal optical control of magnetism. Here, we demonstrate the spatiotemporal observation of patterned ultrafast demagnetization dynamics in permalloy mediated by propagating surface plasmon polaritons with sub-picosecond time- and sub-μm spatial- scales by employing Lorentz ultrafast electron microscopy combined with excitation through transient optical gratings. We discover correlated spatial distributions of demagnetization amplitude and surface plasmon polariton intensity, the latter characterized by photo-induced near-field electron microscopy. Furthermore, by comparing the results with patterned ultrafast demagnetization dynamics without surface plasmon polariton interaction, we show that the demagnetization is not only enhanced but also exhibits a spatiotemporal modulation near a spatial discontinuity (plasmonic hot spot). Our findings shed light on the intricate interplay between surface plasmons and spins, offer insights into the optimized control of optical excitation of magnetic materials and push the boundaries of ultrafast manipulation of magnetism.

MXene is a promising energy storage material for miniaturized microbatteries and microsupercapacitors (MSCs). Despite its superior electrochemical performance, only a few studies have reported MXene-based ultrahigh-rate (>1000 mV s−1) on-paper MSCs, mainly due to the reduced electrical conductance of MXene films deposited on paper. Herein, ultrahigh-rate metal-free on-paper MSCs based on heterogeneous MXene/poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS)-stack electrodes are fabricated through the combination of direct ink writing and femtosecond laser scribing. With a footprint area of only 20 mm2, the on-paper MSCs exhibit excellent high-rate capacitive behavior with an areal capacitance of 5.7 mF cm−2 and long cycle life (>95% capacitance retention after 10,000 cycles) at a high scan rate of 1000 mV s−1, outperforming most of the present on-paper MSCs. Furthermore, the heterogeneous MXene/PEDOT:PSS electrodes can interconnect individual MSCs into metal-free on-paper MSC arrays, which can also be simultaneously charged/discharged at 1000 mV s−1, showing scalable capacitive performance. The heterogeneous MXene/PEDOT:PSS stacks are a promising electrode structure for on-paper MSCs to serve as ultrafast miniaturized energy storage components for emerging paper electronics. 

On-paper microsupercapacitors (MSCs) are a key energy storage component for disposable electronics that are anticipated to essentially address the increasing global concern of electronic waste. However, nearly none of the present on-paper MSCs combine eco-friendliness with high electrochemical performance (especially the rate capacity). In this work, highly reliable conductive inks based on the ternary composite of poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS), graphene quantum dots and graphene are developed for scalable inkjet printing of compact (footprint area ≈ 20 mm2) disposable MSCs on commercial paper substrates. Without any post treatment, the printed patterns attain a sheet resistance as low as 4 Ω ▫−1. The metal-free all-solid-state MSCs exhibit a maximum areal capacitance > 2 mF cm−2 at a high scan rate of 1000 mV s−1, long cycle life (>95% capacitance retention after 10 000 cycles), excellent flexibility, and long service time. Remarkably, the “totally metal-free” MSC arrays are fully inkjet printed on paper substrates and also exhibit high rate performance. The life cycle assessment indicates that these printed devices have much lower eco-toxicity and global warming potential than other on-paper MSCs.

Manipulation and detection of spins at the nanoscale is of considerable contemporary interest as it may not only facilitate a description of fundamental physical processes but also plays a critical role in the development of spintronic devices. Here, we describe the application of a novel combination of transient grating excitation with Lorentz ultrafast electron microscopy to control and detect magnetization dynamics with combined nanometer and picosecond resolutions. Excitation of Ni80Fe20 thin film samples results in the formation of transient coherently precessing magnetic gratings. From the time-resolved results, we extract detailed real space information of the magnetic precession, including local magnetization, precession frequency, and relevant decay factors. The Lorentz contrast of the dynamics is sensitive to the alignment of the in-plane components of the applied field. The experimental results are rationalized by a model considering local demagnetization and the phase of the precessing magnetic moments. We envision that this technique can be extended to the study of spin waves and dynamic behavior in ferrimagnetic and antiferromagnetic systems.

Efforts to understand matter at ever-increasing spatial and temporal resolutions have led to the development of instruments such as the ultrafast transmission electron microscope (UEM) that can capture transient processes with combined nanometer and picosecond resolutions. However, analysis by UEM is often associated with extended acquisition times, mainly due to the limitations of the electron gun. Improvements are hampered by tradeoffs in realizing combinations of the conflicting objectives for source size, emittance, and energy and temporal dispersion. Fundamentally, the performance of the gun is a function of the cathode material, the gun and cathode geometry, and the local fields. Especially shank emission from a truncated tip cathode results in severe broadening effects and therefore such electrons must be filtered by applying a Wehnelt bias. Here we study the influence of the cathode geometry and the Wehnelt bias on the performance of a photoelectron gun in a thermionic configuration. We combine experimental analysis with finite element simulations tracing the paths of individual photoelectrons in the relevant 3D geometry. Specifically, we compare the performance of guard ring cathodes with no shank emission to conventional truncated tip geometries. We find that a guard ring cathode allows operation at minimum Wehnelt bias and improve the temporal resolution under realistic operation conditions in an UEM. At low bias, the Wehnelt exhibits stronger focus for guard ring than truncated tip cathodes. The increase in temporal spread with bias is mainly a result from a decrease in the accelerating field near the cathode surface. Furthermore, simulations reveal that the temporal dispersion is also influenced by the intrinsic angular distribution in the photoemission process and the initial energy spread. However, a smaller emission spot on the cathode is not a dominant driver for enhancing time resolution. Space charge induced temporal broadening shows a close to linear relation with the number of electrons up to at least 10 000 electrons per pulse. The Wehnelt bias will affect the energy distribution by changing the Rayleigh length, and thus the interaction time, at the crossover.

Ultrafast optical control of magnetic textures offers new opportunities for energy-efficient, high-speed spintronic devices. While uniform magnetization reversal via all-optical switching is well established, the formation dynamics of non-uniform domain walls (DWs) under ultrafast excitation remain poorly understood. Here, we use Lorentz ultrafast electron microscopy combined with transient optical grating excitation to directly image the real-time formation of DWs in a ferrimagnetic GdFeCo film. We observe a rapid evolution from disordered spin contrast to ordered DW arrays within 10 ps, including a transient, strongly asymmetric DW state. In a narrow fluence window, short-lived DWs form and spontaneously vanish within picoseconds. Multiscale simulations combining atomistic spin dynamics and micromagnetics reveal a nonlinear nucleation pathway involving a hybrid transition state where localized, unstable spin textures coalesce into metastable DWs. This nonequilibrium mechanism explains the observed asymmetry and spatial ordering, and establishes a framework for controlling spin textures in magnetic materials on femtosecond timescales.

Direct imaging of spin waves is critical for advancing both fundamental understanding of magnetic dynamics and applied magnonics. However, achieving high spatiotemporal resolution of spin wave propagation dynamics remains a challenge. Here, we demonstrate spatiotemporal observation of laser excited spin waves in a Ni80Fe20 (permalloy) thin film using Lorentz ultrafast electron microscopy with a Gaussian pump spatially modulated by an optical transient grating (TG). Strikingly, we observe multiple concentric spin-wave wavefronts converging from the sample edges toward the center of the laser spot. These propagating wavefronts modulate the magnetic grating contrast induced by optical TG and are readily detected in the Lorentz images. Micromagnetic simulations reproduce the spatiotemporal propagation of the observed wavefronts. This work establishes structured optical excitation as a powerful and universal strategy for enhancing magnetic contrast and enabling real-space imaging of weak, long-wavelength spin wave dynamics, opening new opportunities for magnonic visualization.