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Ultrafast stimuli can stabilize metastable states of matter inaccessible by equilibrium means. Establishing the spatiotemporal link between ultrafast excitation and metastability is crucial to understand these phenomena. Here we utilize single-shot optical pump–X-ray probe measurements to capture snapshots of the emergence of a persistent polar vortex supercrystal in a heterostructure that hosts a fine balance between built-in electrostatic and elastic frustrations by design. By perturbing this balance with photoinduced charges, an initially heterogeneous mixture of polar phase disorders within a few picoseconds, leading to a state composed of disordered ferroelectric and suppressed vortex orders. On the picosecond–nanosecond timescales, transient labyrinthine fluctuations develop, accompanied by the recovery of the vortex order. On longer timescales, these fluctuations are progressively quenched by dynamical strain modulations, which drive the collective emergence of a single vortex supercrystal phase. Our results, corroborated by dynamical phase-field modelling, reveal non-equilibrium pathways following the ultrafast excitation of designer systems to persistent metastability.

High-Mn steels are widely used in engineering applications because of their high strength, high hardness, and excellent toughness. In the industrial production of high-Mn steel, the steel is easy to be oxidized during the homogenization process, which may affect the properties of high-Mn steel. In this work, high-Mn high-Al steel with composition of (25–32)wt-%Mn-(8–11)wt-%Al-1wt-%C-Fe was prepared, the oxidation behavior and subsurface phase transformation of steel at 800 °C–1200 °C were investigated by thermogravimetric analysis, scanning electron microscope and X-ray diffraction. The results show that the curve of oxidation weight gain with time is in good agreement with linear equations below 900 °C, which obey the parabolic rate law in the temperature range of 1000 °C–1200 °C. The steel matrix would be covered by the oxide scale earlier at higher temperatures, which decreases the oxidation reaction rate and makes the turning point of the oxidation reaction rate reach faster at higher temperatures. The Mn-depleted zone resulting from the selective oxidation of Mn is formed in the steel matrix epidermis, leading to the subsurface phase transformation, which may deteriorate the steel properties.

Software-based distributed shared memory (DSM) allows multiple processes to access shared data without the need for specialized hardware. However, this flexibility comes at a significant cost due to the need for data synchronization. One approach to mitigate these costs is to relax the consistency model, which can lead to delayed updates to the shared data. This approach typically requires the use of explicit synchronization primitives to regulate access to the shared memory and determine the timing of data synchronization. To circumvent the need for explicit synchronization, an alternative approach is to manage shared memory transparently using the underlying system. While this can simplify programming, it often imposes a fixed granularity for data sharing, which can limit the expansion of the coherence domain and increase the synchronization requirements. To overcome this limitation, we propose an abstraction called the elastic coherence domain, which dynamically adjusts the scope of data synchronization and is supported by the underlying system for transparent management of shared memory. The experimental results show that this approach can improve the efficiency of memory sharing in distributed environments.

Asymmetric Pd-catalyzed three-component carboamination reactions of dienes to construct chiral cyclohexenylamines, which are of great importance in many fields of chemistry, have remained largely unexplored. Here, we demonstrate a highly enantio- and regioselective Pd/Ming-Phos-catalyzed carboamination reactions of 1,3-cyclohexadiene with readily available aryl iodides and anilines for facile access to diverse valuable chiral cyclohexenylamines. The process shows excellent functional group tolerance, easy scalability, and mild conditions. Moreover, mechanistic studies suggest that this reaction has a first-order dependence on the concentration of the palladium catalyst and aniline.

A codesign approach is proposed in this communication for an efficient design of frequency-scanning coupled-patch arrays (CPAs) with wide scanning range and high scanning rate. It combines characteristic mode analysis (CMA) and coupling matrix analysis, where the former is employed for radiation pattern synthesis, while the latter tunes the feeding reflection and mode excitation based on a coupled-resonator network model. With this systematic approach, it becomes efficient to control both beam scanning properties and feeding reflection. Third-order and sixth-order design examples are provided to validate the proposed method. The sixth-order CPA achieves a wide scanning range of 73° (from −45° to 28° across broadside) and a high scanning rate of 26.1°/1%. Both are higher than other reported CPAs.

The 14-T magnetic resonance imaging (MRI) superconducting magnet utilizes reinforced multifilament Nb3Sn wires and multifilament NbTi wires to generate the required magnetic field. The resistances of the Nb3Sn-NbTi superconducting joints are crucial to the temporal field stability of the magnet operation in persistent mode. The resistance of each joint is required to be lower than 10−11 Ω under a 0.5 T background magnetic field to keep the temporal field drift lower than 0.1 ppm/hour. This paper presents the fabrication of multifilament Nb3Sn-NbTi superconducting joints and the measurement of their resistances. The joints were fabricated by the solder matrix replacement method using PbBi as the solder in an open-air environment. The samples were tested by an apparatus that was developed based on the current-decay method and can provide a background field up to 1 T. The sample loop with a Nb3Sn wire and a NbTi wire contains two Nb3Sn-NbTi joints. The Nb3Sn wire undergoes the heat treatment before the fabrication of superconducting joints with the NbTi wire. The measured results indicate that the joints can carry a current up to 809.8 A with a resistance lower than 6.20 × 10−13 Ω without a background field. Under a 1 T background field, the joints can carry a current up to 481.5 A with a resistance lower than 1.24 × 10−12 Ω, which meet the requirement of the 14-T MRI superconducting magnet.