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Flexible piezoresistive sensors that offer both high sensitivity and a broad linear detection range are highly desirable for wearable health monitoring, as they facilitate simplified circuit design and enable accurate detection of subtle physiological signals. However, existing sensors typically encounter an intrinsic trade‐off between sensitivity and linearity, primarily due to structural stiffening under increasing pressure. Here, a flexible piezoresistive pressure sensor featuring dual‐graded microstructures (DGM) is reported, formed by embedding multi‐walled carbon nanotubes (MWCNTs) into a thermoplastic polyurethane matrix. Leveraging the synergistic effects of progressive structural deformation and MWCNTs‐induced tunneling conduction, the sensor achieves a high sensitivity of 69.8 kPa⁻¹ and a broad linear sensing range up to 300 kPa (R2 ≈ 0.998). The sensor also exhibits rapid response‐relaxation time (totaling 5 ms), stable high‐frequency detection up to 200 Hz, and good stability over 5 000 repeated loading cycles. Demonstrations in physiological monitoring confirm the sensor's capability to precisely capture detailed radial pulse waveforms, respiratory rhythms, and subtle heartbeat‐induced vibrations. Both a scalable, cost‐effective structural fabrication and good overall sensing performance establish the DGM‐based sensor as a promising candidate for advanced wearable healthcare monitoring devices. A flexible piezoresistive pressure sensor with dual‐graded microstructures achieves both high sensitivity (69.8 kPa⁻¹) and a broad linear range up to 300 kPa (R2 = 0.997). Synergizing structural deformation and tunneling conduction, it enables rapid, stable, and accurate detection of subtle physiological signals, offering a scalable and cost‐effective solution for next‐generation wearable health monitoring

The carbon sink in pantropical biomes play a crucial role in modulating the inter‐annual variations of global terrestrial carbon balance and is threatened by extreme climate events. However, it has not been carefully examined whether an increase in tropical gross primary productivity (GPP) can compensate the decrease during precipitation anomalies. Using the asymmetry index (AI) and multiple GPP products, we assessed responses of pantropical GPP to precipitation anomalies during 2001–2022. Positive AI indicates that GPP increases are greater than GPP decreases during precipitation anomalies, and vice versa. Our results showed an average negative pantropical GPP asymmetry, that is, GPP decreases exceeded the GPP increases during precipitation anomalies. In addition, a positive AI was found in tropical hyper‐arid and arid regions, which is opposite to the negative AI observed in tropical semi‐arid, sub‐humid, and humid regions. This suggest that tropical GPP asymmetry changes from positive to negative as the moisture increases. Notably, a significant decreasing trend of negative AI was observed over the entire tropical region, indicating that the negative effect of inter‐annual precipitation variations on pantropical vegetation productivity has enhanced. Considering the model predicted increasing climate variability and extremes, the negative impact of precipitation variability on tropical carbon cycle may continue to intensify. Lastly, the divergence in AI estimates among multiple GPP products highlight the need to further improve our understanding of the response of tropical carbon cycle to climate changes, especially for the tropical humid regions. Plain Language Summary Tropical biomes play an essential role in controlling the global carbon balance but has been threatened by extreme climate events recently. Whether the increase in tropical GPP can compensate the GPP decrease during precipitation anomalies is still poorly known. In this study, we found an average negative asymmetric GPP response to precipitation anomalies over the entire tropics during 2001–2022, that is, GPP decreases exceeded the GPP increases during precipitation anomalies. Meanwhile, we found that the tropical GPP was shifted from positive asymmetry to negative asymmetry as the moisture increases. Besides, a significantly decreasing trend of GPP asymmetry was observed over the study period, suggesting that the negative effect of inter‐annual precipitation variations on pantropical GPP has intensified. Key Points We find the tropical GPP shows a negative asymmetric response to precipitation anomalies over the past two decades An overall decreasing trend of the GPP asymmetry was observed over the entire tropical region Anisohydric biomes have a stronger positive asymmetric response of GPP to precipitation anomalies than isohydric biomes

Recently, MXenes stand out as an attractive type of two-dimensional layered material. Their unique deformable surface terminations and rich chemical compositions endow MXenes with adjustable and customizable characteristics, resulting in excellent linear/non-linear electromagnetic wave responses and versatile applications. In order to get more insights in this area, here, we make a comprehensive summarization of the interactions according to the response principles between MXenes and electromagnetic waves, such as absorption, scattering, emission, transmission, resonance, etc. The latest progress of corresponding applications is also introduced in detail, including photothermal conversion, photo-/photoelectro-catalysis, electromagnetic interference shielding, photoluminescence, tumor therapy, transparent electrode, photodetector, surface-enhanced Raman scattering, plasmonic absorption, saturated absorption, etc. Finally, the challenges and opportunities are discussed to look forward to the beautiful future of MXenes and MXene-based electromagnetic wave responses.

The term “spatial variability of seismic ground motions” denotes the differences in the amplitude and phase content of seismic motions. The effect of such spatial variability on the structural response is still an open issue. In-situ experiments may be helpful in order to answer the questions regarding both the quantification of the spatial variability of the ground motion within the dimensions of a structure as well as the effect on its dynamic response. The goal of the present study is to quantify the variability of the seismic ground motion accelerations in the shallow sedimentary basin of Argostoli, Greece, and thereafter to identify its effect on the linear and non-linear elasto-plastic response of a single degree of freedom system in terms of spectral displacements. Around 400 earthquakes are used, recorded by the 21-element very dense seismological array deployed in Argostoli with inter-station spacing ranging from 5 to 160 meters. The seismic motion variability, evaluated in terms of spectral accelerations, is found to be significant and to increase with inter-station distance and frequency. Thereafter, the amplitude variability in terms of spectral displacements, which is indeed the linear response of a single degree of freedom (SDOF) system with various fundamental periods, is compared with the amplitude variability of a SDOF with non-linear elasto-plastic response. The variability of the maximum top displacement of the linear single degree of freedom system is estimated to be on average 12% with larger variabilities to be observed within two narrow frequency ranges (between 1.5 and 1.7 Hz and between 3 and 4 Hz). Such high variabilities are caused by locally edge-generated diffracted surface waves. The non-linear perfectly elasto-platic structural response of the SDOF system shows that although the variability has the same trends as in the case of linear response, it is almost constantly increased by 5%.

The non-linear seismic response of in-plan asymmetric systems has been extensively studied since the 1980s. Nevertheless, most of the research effort has been devoted to the study of specific asymmetric buildings and, even though relevant progresses have been achieved in the understanding of the complex translational-to-torsional coupled response of such systems, a complete understanding of the seismic behaviour of in-plan asymmetric buildings is still missing. In this paper a systematic study of the seismic response of linear and non-linear one-storey asymmetric structures is presented. A mixed analytical–numerical approach, the so-called “alpha” method, is used to investigate the non-linear seismic response of a wide range of in-plan asymmetric structures with the aim of providing general trends of behavior.

We present the linear response function of bond-orders (LRF-BO) based on a real space integration scheme for molecular systems. As in the case of the LRF of density, the LRF-BO is defined as the response of the bond order of the molecule for the virtual perturbation. Our calculations show that the LRF-BO enables us not only to detect inductive and resonating effects of conjugating systems, but also to predict pKa values on substitution groups via linear relationships between the Hammett constants and the LRF-BO values for meta- and para-substituted benzoic acids. More importantly, the LRF-BO values for the O-H bonds strongly depend on the sites to which the virtual perturbation is applied, implying that the LRF-BO values include essential information about reaction mechanism of the acid-dissociation of substituted benzoic acids.

A photon avalanche (PA) effect that occurs in lanthanide-doped solids gives rise to a giant nonlinear response in the luminescence intensity to the excitation light intensity. As a result, much weaker lasers are needed to evoke such PAs than for other nonlinear optical processes. Photon avalanches are mostly restricted to bulk materials and conventionally rely on sophisticated excitation schemes, specific for each individual system. Here we show a universal strategy, based on a migrating photon avalanche (MPA) mechanism, to generate huge optical nonlinearities from various lanthanide emitters located in multilayer core/shell nanostructrues. The core of the MPA nanoparticle, composed of Yb3+ and Pr3+ ions, activates avalanche looping cycles, where PAs are synchronously achieved for both Yb3+ and Pr3+ ions under 852 nm laser excitation. These nanocrystals exhibit a 26th-order nonlinearity and a clear pumping threshold of 60 kW cm−2. In addition, we demonstrate that the avalanching Yb3+ ions can migrate their optical nonlinear response to other emitters (for example, Ho3+ and Tm3+) located in the outer shell layer, resulting in an even higher-order nonlinearity (up to the 46th for Tm3+) due to further cascading multiplicative effects. Our strategy therefore provides a facile route to achieve giant optical nonlinearity in different emitters. Finally, we also demonstrate applicability of MPA emitters to bioimaging, achieving a lateral resolution of ~62 nm using one low-power 852 nm continuous-wave laser beam.A general mechanism, migrating photon avalanche, can generate large optical nonlinearity from various lanthanides emitters at the nanoscale.

We establish the physical origins of chemical transferability from the perspective of the nearsightedness of electronic matter. To do this, we explicitly evaluate the response of electron density to a change in the system, at constant chemical potential, by computing the softness kernel, s(r, r′). The softness kernel is nearsighted, indicating that under constant-chemical-potential conditions like dilute solutions changing the composition of the molecule at r has only local effects and does not have any significant impact on the reactivity at positions r′ far away from point r. This locality principle elucidates the transferability of functional groups in chemistry.

The nature of order in low-temperature phases of some materials is not directly seen by experiment. Such “hidden orders” (HOs) may inspire decades of research to identify the mechanism underlying those exotic states of matter. In insulators, HO phases originate in degenerate many-electron states on localized f or d shells that may harbor high-rank multipole moments. Coupled by intersite exchange, those moments form a vast space of competing order parameters. Here, we show how the ground-state order and magnetic excitations of a prototypical HO system, neptunium dioxide NpO₂, can be fully described by a low-energy Hamiltonian derived by a many-body ab initio force theorem method. Superexchange interactions between the lowest crystal-field quadruplet of Np4+ ions induce a primary noncollinear order of time-odd rank 5 (triakontadipolar) moments with a secondary quadrupole order preserving the cubic symmetry of NpO₂. Our study also reveals an unconventional multipolar exchange striction mechanism behind the anomalous volume contraction of the NpO₂ HO phase.

We study the thermodynamics of open systems weakly driven out-of-equilibrium by nonconservative and time-dependent forces using the linear regime of stochastic thermodynamics. We make use of conservation laws to identify the potential and nonconservative components of the forces. This allows us to formulate a unified near-equilibrium thermodynamics. For nonequilibrium steady states, we obtain an Onsager theory ensuring nonsingular response matrices that is consistent with phenomenological linear irreversible thermodynamics. For time-dependent driving protocols that do not produce nonconservative forces, we identify the equilibrium ensemble from which Green–Kubo relations are recovered. For arbitrary periodic drivings, the averaged entropy production (EP) is expressed as an independent sum over each driving frequency of non-negative contributions. These contributions are bilinear in the nonconservative and conservative forces and involve a novel generalized Onsager matrix that is symmetric. In the most general case of arbitrary time-dependent drivings, we advance a novel decomposition of the EP rate into two non-negative contributions—one solely due to nonconservative forces and the other solely due to deviation from the instantaneous steady-state—directly implying a minimum EP principle close to equilibrium. This setting reveals the geometric structure of near-equilibrium thermodynamics and generalizes previous approaches to cases with nonconservative forces.