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We investigate the formation of condensates in a binary lattice gas in the presence of chiral interactions. These interactions differ between a given microscopic configuration and its mirror image. We consider a two-dimensional lattice gas with nearest-neighbour interactions, to which we add interactions involving favoured local structures (FLSs) that are chiral. We focus on FLSs that have the shape of the letter L and explore condensate formation through simulations and analytical calculations. At low temperature, this model can exhibit four different phases that are characterised by different periodic tiling patterns, depending on the strength of interactions and the chemical potential. When particle numbers are conserved, some of these phases can coexist. We analyse the structure and surface tension of interfaces between coexisting phases and determine the shapes of minimal free energy of crystalline condensates. We show that these shapes can be quadrilaterals or octagons of different orientation and symmetry.

It has been suggested that ion foreshock waves originating in the solar wind upstream of the quasi-parallel (Q-||) shock can impact the planetary magnetosphere leading to standing shear Alfvén waves, i.e., the field line resonances (FLRs). In this paper, we carry out simulations of interaction between the solar wind and terrestrial magnetosphere under radial interplanetary magnetic field conditions by using a 3-D global hybrid model, and show the properties of self-consistently generated field line resonances through direct mode conversion in magnetospheric response to the foreshock disturbances for the first time. The simulation results show that the foreshock disturbances from the Q-|| shock can excite magnetospheric ultralow-frequency waves, among which the toroidal Alfvén waves are examined. It is found that the foreshock wave spectrum covers a wide frequency range and matches the band of FLR harmonics after excluding the Doppler shift effects. The fundamental harmonic of field line resonances dominates and has the strongest wave power, and the higher the harmonic order, the weaker the corresponding wave power. The nodes and anti-nodes of the odd and even harmonics in the equatorial plane are also presented. In addition, as the local Alfvén speed increases earthward, the corresponding frequency of each harmonic increases. The field-aligned current in the cusp region indicative of the possibly observable aurora is found to be a result of magnetopause perturbation which is caused by the foreshock disturbances, and a global view substantiating this scenario is given. Finally, it is found that when the solar wind Mach number decreases, the strength of both field line resonance and field-aligned current decreases accordingly.

In this study, we identified 51 dayside diffuse auroral patches and examined their two‐dimensional evolutions by using the Time History of Events and Macroscale Interactions during Substorms probes and the ground‐based all‐sky imager at the South Pole. Two typical events show diffuse auroral patches associated with upstream dynamic pressure enhancements of the bow shock and magnetospheric compressions, followed by their east–west propagations. The statistical results suggest that most conjunction events were associated with foreshock activities, while the remaining events were associated with dynamic pressure enhancements in the pristine solar wind. These azimuthal motions can be either eastward or westward, with initial locations at ∼12–13 and ∼9–10 Magnetic Local Time, respectively, exhibiting a dawn‐dusk asymmetry. Additionally, poleward motions were found in all events. Larger dynamic pressure enhancements correspond to faster poleward motions and could push the initial diffuse auroral brightening toward lower latitudes. These characteristics of their poleward motions were consistent with the Tamao path.

The fast booming of wearable electronics provides great opportunities for intelligent gas detection with improved healthcare of mining workers, and a variety of gas sensors have been simultaneously developed. However, these sensing systems are always limited to single gas detection and are highly susceptible to the inference of ubiquitous moisture, resulting in less accuracy in the analysis of gas compositions in real mining conditions. To address these challenges, we propose a synergistic strategy based on sensor integration and machine learning algorithms to realize precise NH3 and NO2 gas detections under real mining conditions. A wearable sensing array based on the graphene and polyaniline composite is developed to largely enhance the sensitivity and selectivity under mixed gas conditions. Further introduction of backpropagation neural network (BP‐NN) and partial least squares (PLS) algorithms could improve the accuracy of gas identification and concentration prediction and settle the inference of moisture, realizing over 99% theoretical prediction level on NH3 and NO2 concentrations within a wide relative humidity range, showing great promise in real mining detection. As proof of concept, a wireless wearable bracelet, integrated with sensing arrays and machine‐learning algorithms, is developed for wireless real‐time warning of hazardous gases in mines under different humidity conditions. An integratedstrategy that combines sensor arrays with machine learning algorithms is proposed. The wearable sensor array achieves a theoretical concentration prediction accuracy of over 99% within a wide range of relative humidity, enabling precise detection of NH3 and NO2 in real mining conditions, thus facilitating health monitoring of miners.

Micro-thermoelectric coolers are emerging as a promising solution for high-density cooling applications in confined spaces. Unlike thin-film micro-thermoelectric coolers with high cooling flux at the expense of cooling temperature difference due to very short thermoelectric legs, thick-film micro-thermoelectric coolers can achieve better comprehensive cooling performance. However, they still face significant challenges in both material preparation and device integration. Herein, we propose a design strategy which combines Bi 2 Te 3 -based thick film prepared by powder direct molding with micro-thermoelectric cooler integrated via phase-change batch transfer. Accurate thickness control and relatively high thermoelectric performance can be achieved for the thick film, and the high-density-integrated thick-film micro-thermoelectric cooler exhibits excellent performance with maximum cooling temperature difference of 40.6 K and maximum cooling flux of 56.5 W·cm −2 at room temperature. The micro-thermoelectric cooler also shows high temperature control accuracy (0.01 K) and reliability (over 30000 cooling cycles). Moreover, the device demonstrates remarkable capacity in power generation with normalized power density up to 214.0 μW · cm −2  · K −2 . This study provides a general and scalable route for developing high-performance thick-film micro-thermoelectric cooler, benefiting widespread applications in thermal management of microsystems. The micro-thermoelectric coolers face challenges in high-performance material preparation and high-density device integration. Here, the authors combine Bi 2 Te 3 -based film prepared by powder direct molding with micro-thermoelectric cooler integrated via phase-change batch transfer.

To stabilize the detection signal of palladium-based hydrogen sensors on paper substrates, a graphite intermediate layer was painted on the surface of paper. The graphite-on-paper (GOP) substrate offers advantages such as good thermo-electrical conductivity, low cost, and uncomplicated preparation technology. Quasi-1-dimensional palladium (Pd) thin films with 8 nm and 60 nm thicknesses were deposited on the GOP substrates using the vacuum evaporation technique. Thanks to the unique properties of the GOP substrate, a continuous Pd microfiber network structure appeared after deposition of the ultra-thin Pd film. Additionally, the sensing performance of the palladium-based hydrogen sensor was not affected, whether using GOP or paper substrate at 25 °C. Surprisingly, heating-induced loss of sensitivity was restrained due to the increased electrical conductivity of the GOP substrate at 50 °C.

In this work, we identified 65 auroral arcs that stretched out from the equatorward boundary of auroral oval with azimuthal extensions, and investigated their upstream triggering, by utilizing conjunctions between the THEMIS probes and the all‐sky imagers at AGO P1 and South Pole stations. The results show that the magnetopause motions induced by pressure enhancements associated with IMF discontinuities or foreshock cavities likely generate upward FACs in the closed field lines near the magnetopause. The inward and azimuthal motions of magnetopause caused equatorward‐moving auroral arcs, which extended westward or eastward, centered in the prenoon (12–13 MLT) or postnoon (9–10 MLT) sectors, respectively. The dawn‐dusk asymmetry in this distribution may be due to the contribution from foreshock activities. Furthermore, stronger compression can push the magnetopause further inward, causing FACs and the corresponding discrete auroras to be distributed over a wider region extending further in both latitude and local time. Plain Language Summary It is known that the currents along magnetic field lines can precipitate electrons toward the ionosphere and generate auroral arcs. We identified 65 auroral arcs that stretched out from the equatorward boundary of auroral oval with azimuthal extensions, and investigated their two‐dimensional evolutions, by utilizing conjunctions between the satellites around the magnetosphere and the ground‐based all‐sky imagers. The results show that the magnetopause motions induced by pressure enhancements associated with IMF discontinuities or foreshock cavities likely generate upward currents along magnetic field lines extending westward or eastward, centered in the prenoon or postnoon sectors, respectively. The dawn‐dusk asymmetry in this distribution may be due to the contribution from foreshock cavities. Furthermore, stronger compression can push the magnetopause further inward, causing FACs and the corresponding discrete auroras to be distributed over a wider region extending further in both latitude and local time. Key Points The magnetopause motion induced by pressure enhancements likely generate upward FACs extending either westward or eastward The distribution of the arcs induced by magnetopause motions has a dawn‐dusk asymmetry, which is likely contributed by foreshock cavities Stronger compression can push the magnetopause further inward, causing FACs and the corresponding auroral arcs longer

The long-chain effects of eruptive solar activities on Earth’s magnetosphere, ionosphere, and the mid-to-lower atmospheric circulation are an important theoretical research topic in the fields of space weather and atmospheric science. Understanding the impact of space weather on aviation holds substantial economic value. It is well-known that flight times for polar routes may increase during solar proton events (SPEs) due to the necessity of avoiding high-energy particles. However, changes in atmospheric circulation due to SPEs and their impact on flight times have not been reported yet. This study systematically analyzed 15 pairs of representative international air routes, comprising a total of 16,037 flight records affected by the polar jet stream between 2015 and 2019. An unpaired two-sample two-tailed t-test revealed that 86.67% of westbound flights had shorter durations, while 86.67% of eastbound flights had longer durations during SPEs compared to quiet periods, with an average change of approximately 7 min. Further investigation into 42 SPEs during an entire solar cycle (11 years) indicates that the poleward shift of the polar jet stream, associated with high-energy particle precipitation, is the fundamental reason for the asymmetrical changes in flight times. This is the first report detailing the impact of SPEs on atmospheric circulation and flight times. Our findings reveal the long-chain mechanism by which SPEs directly influence the circulation of Earth’s lower atmosphere. These results are also crucial for aviation, as they can help airlines optimize routes, reduce fuel costs, and contribute to climate change mitigation efforts.

Magnetic reconnection is a process that can rapidly convert magnetic field energy into plasma thermal energy and kinetic energy, and it is also an important energy conversion mechanism in space physics, astrophysics and plasma physics. Research related to analytical solutions for time-dependent three-dimensional magnetic reconnection is extremely difficult. For decades, several mathematical descriptions have been developed regarding different reconnection mechanisms, in which the equations based on magnetohydrodynamics theory outside the reconnection diffusion region are widely accepted. However, the equation set cannot be analytically solved unless specified constraints are imposed or the equations are reduced. Based on previous analytical methods for kinematic stationary reconnection, here the analytical solutions for time-dependent kinematic three-dimensional magnetic reconnection are discussed. In contrast to the counter-rotating plasma flows that existed in steady-state reconnection, it is found that spiral plasma flows, which have never been reported before, can be generated if the magnetic field changes exponentially with time. These analyses reveal new scenarios for time-dependent kinematic three-dimensional magnetic reconnection, and the deduced analytical solutions could improve our understanding of the dynamics involved in reconnection processes, as well as the interactions between the magnetic field and plasma flows during magnetic reconnection.

To improve the hydrogen detection performance, a flexible palladium-based hydrogen sensor was designed and fabricated on normal photocopy paper. The paper substrate offers advantages such as light weight, low cost, flexibility and unique surface texture. A conventional vacuum evaporation technique was utilized for 60 nm palladium deposition on the paper and glass substrates. The unique surface texture of the paper effectively increased the surface area to volume ratio for the sensing element, which achieved a higher gas response with faster speed than the glass-based sensor. In addition, we investigated the temperature impacts on sensing performance of the paper-based hydrogen sensor at room temperature and 50 °C. Furthermore, the flexibility test results of the paper-based hydrogen sensor showed that the sensing performances were impervious to mechanical bending of 5.7°.