Search

To ensure the users’ immersive experience in cross-modal communication, overcoming the end-to-end (E2E) latency through prediction has attracted attention and shown its superiority. However, existing prediction schemes encounter formidable challenges in the presence of multi-modal signals, primarily to adapt and satisfy the prediction requirements of diverse multi-modal services, as well as to fully exploit and effectively utilize the correlation features of multi-modal signals for precise prediction. To this end, this work presents a flexible prediction scheme for low-latency cross-modal communication. Specifically, we first propose an adaptive prediction-aware cross-modal communication framework, which reduces the delay by predicting and transmitting the future multi-modal signals in advance, and flexibly adjusts the prediction horizon to satisfy the prediction accuracy of different multi-modal services. Next, we design an information gain-assisted graph attention (IGGA) method for cross-modal signal prediction, which leverages the graph attention block to extract the intra-modal, inter-modal spatial and temporal correlation features, and effectively optimize and utilize these features with the information gain (IG), thereby facilitating precise cross-modal signal prediction. Finally, numerical experiments conducted on a self-built dataset, a public dataset, and a multi-modal acupuncture platform demonstrate the superiority of the proposed scheme in low-latency cross-modal communication.

Studies have increasingly focussed on the relationship between periodontitis (PD) and preeclampsia (PE). However, conclusions have not been consistent, and it is unclear whether any causal relationship exists between them and whether causality is bidirectional. This study employed Mendelian randomisation (MR) analysis to investigate the potential bidirectional causal relationship between PD and PE.

Metal–organic frameworks (MOFs) have emerged as a highly promising platform for various sensing applications due to their tunable structures and functionalities. In the present work, a Eu3+-doped mixed-ligand MOF, namely, the Eu3+@UiO-66-IPA, exhibited excellent luminescent properties and high fluorescence stability in aqueous media, displaying dual-emission peaks under 395 and 615 nm excitation that were readily visible to the naked eye. Importantly, the presence of fluoride ions (F–) promoted the “antenna effect” between the ligand and the Eu3+centers, which significantly enhanced the emission intensity of the Eu3+characteristic peak. In addition, the addition of F–also inhibited the quenching effect of high-energy O–H bonds existing in the aqueous environment. Notably, Eu3+@UiO-66-IPA demonstrated exceptional selectivity for F–over a range of competing anions, with a remarkable limit of detection as low as 0.22 μM. The developed Eu3+-doped mixed-ligand MOF system offers a highly promising strategy for the simple and accurate sensing of F–in practical applications.

With countries proposing the goal of carbon neutrality, the clean transformation of energy structure has become a hot and trendy issue internationally. Renewable energy generation will account for the main proportion, but it also leads to the problem of unstable electricity supply. At present, large-scale energy storage technology is not yet mature. Improving the flexibility of coal-fired power plants to suppress the instability of renewable energy generation is a feasible path. Thermal energy storage is a feasible technology to improve the flexibility of coal-fired power plants. This article provides a review of the research on the flexibility transformation of coal-fired power plants based on heat storage technology, mainly including medium to low-temperature heat storage based on hot water tanks and high-temperature heat storage based on molten salt. The current technical difficulties are summarized, and future development prospects are presented. The combination of the thermal energy storage system and coal-fired power generation system is the foundation, and the control of the inclined temperature layer and the selection and development of molten salt are key issues. The authors hope that the research in this article can provide a reference for the flexibility transformation research of coal-fired power plants, and promote the application of heat storage foundation in specific coal-fired power plant transformation projects.

With the increasing demand for energy and worsening environmental issues, the application of photothermal materials has been widely explored due to their high energy conversion capabilities and environmental friendliness. In this work, metal–carbon fiber composites were prepared and subjected to photothermal and water evaporation performance tests alongside pure metals and pyrolytic phenolic resin materials. The results show that the addition of metals effectively improved the photothermal efficiency by narrowing the molecular energy gaps of the materials, indicating a strong synergistic enhancement effect between metals and carbon materials. This study provides a theoretical basis for the design of high-performance photothermal conversion materials.

The possible mechanism of metal toxicity is oxidative stress and mitochondrial DNA damage. However, the association between environmental metal exposure and mitochondrial DNA damage and the potential mediators remain unclear. In this study, a total of 155 participants from general population were enrolled. In 2016, we measured participants’ blood and urinary chromium, cadmium, manganese, and lead concentrations, serum malondialdehyde (MDA) concentration, urinary 8-hydroxy-2 deoxyguanosine (8-OHdG) concentration, serum activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px). In 2018, we measured participants’ serum mitochondrial DNA polymerase γ (mtDNApolγ) activity, serum mitochondrial transcription factor A (mtTFA) activity, and mitochondrial DNA copy number (mtDNACN). We used general liner regression model and mediation analysis to explore the associations and potential mediation effects, respectively. Blood cadmium was associated with GSH-Px (βDoubling increase= 12.48), blood lead was associated with SOD (βDoubling increase= 5.41), and blood chromium was associated with mtDNApolγ (βDoubling increase=  − 0.54; βTertile 3 vs 1=  − 0.24) and mtDNACN (βDoubling increase=  − 0.22). Urinary cadmium was associated with mtDNApolγ (βTertile 3 vs 1= 0.22) and 8-OHdG (βDoubling increase= 0.24). We did not find a significant mediation effect of oxidative stress on the association between metal exposure and mtDNA damage, but we found that mtDNApolγ accounted for 16% of the association between blood Cr and mtDNACN (P= 0.1). The findings suggest that metal exposure was associated with oxidative stress and mtDNA damage, and mtDNA transcription replicase might mediate the association between metal exposure and mtDNA damage.

In this paper, we study symbol-level precoding (SLP) design for time-domain peak-to-average power ratio (PAPR) reduction in a multi-user MISO-OFDM transmission through the idea of constructive interference (CI). Specifically, we design the precoded transmit signals that minimize the symbol-level transmit power subject to per-antenna time-domain PAPR constraint and CI condition, using the knowledge of both data information and channel state information (CSI), based on which a non-convex problem is established. This non-convex problem is transformed into a convex one by the vectorization and relaxation method. For the relaxed problem, we employ Lagrangian method and Karush-Kuhn-Tucker (KKT) conditions to obtain a closed-form expression on the precoded signals as a function of the Lagrangian multipliers. Subsequently, we study the dual problem and obtain the optimal Lagrangian multipliers via the proposed alternating iterative algorithm. We further consider the practical communication scenario with imperfect CSI, where the original CI constraint is transformed into a probabilistic constraint in order to achieve robustness against statistically CSI errors. Numerical results validate that the proposed low-complexity algorithm achieves an enhanced performance over existing methods in terms of transmit power, PAPR and computation complexity, both in ideal perfect CSI and practical imperfect CSI cases.

We propose a parallel constructive interference (CI)-based symbol-level precoding (SLP) approach for massive connectivity in the downlink of multiuser multiple-input single-output (MU-MISO) systems, with only local channel state information (CSI) used at each processor unit and limited information exchange between processor units. We explore and reveal the separability of the SLP model. By reformulating the power minimization (PM) SLP problem and exploiting the separability of the corresponding reformulation, the original problem is decomposed into several parallel subproblems via the ADMM framework with closed-form solutions, leading to a substantial reduction in computational complexity. The sufficient condition for guaranteeing the convergence of the proposed approach is derived, based on which an adaptive parameter tuning strategy is proposed to accelerate the convergence rate. To avoid the large-dimension matrix inverse operation, an efficient algorithm is proposed by employing the standard proximal term and by leveraging the singular value decomposition (SVD). Furthermore, a prox-linear proximal term is adopted to fully eliminate the matrix inversion, and a parallel inverse-free SLP (PIF-SLP) algorithm is finally obtained. Numerical results validate our derivations above, and demonstrate that the proposed PIF-SLP algorithm can significantly reduce the computational complexity compared to the state-of-the-arts.

Background/Objectives: Bariatric surgery, as indicated for treatment of morbid obesity, has been studied in association with short term effects on ocular pathology. However, effects of surgery on postoperative disease incidence is largely unknown. Subjects/Methods: In this retrospective cohort study, the TriNetX United States Collaborative Network national database, was queried for patients with an ICD-10 code for morbid obesity and a procedural code for bariatric surgery. Patients were propensity score matched across baseline demographics at the time of surgery and compared to those presenting with an ICD10 code for morbid obesity with no records of a procedural code for bariatric surgery, identifying 42,408 patients per cohort. New diagnoses or procedural codes found after the surgical index date for diabetic retinopathy, age-related macular degeneration, glaucoma, low vision, and blindness along with pertinent treatment metrics were monitored. Results: Bariatric surgery was found to be associated with reduced future risk of diabetic retinopathy (RR: 0.283; 95% CI: 0.252–0.319), macular edema (RR: 0.224; 95% CI: 0.170–0.297), vitreous hemorrhage (RR: 0.459; 95% CI: 0.323–0.653), ocular hypertension (RR: 0.387; 95% CI: 0.387–0.487), glaucoma (RR: 0.360; 95% CI: 0.326–0.399), use of ocular pressure lowering medications (RR: 0.565; 95% CI: 0.496–0.644), age-related macular degeneration (RR: 0.628; 95% CI: 0.447–0.882), cataract surgery (RR: 0.524; 95% CI: 0.448–0.612), and low vision and blindness (RR: 0.328; 95% CI: 0.294–0.365) compared to patients not surgically managed. Conclusions: The present analysis comprising a large US cohort of patients suggests that bariatric surgery is associated with a decreased risk of future ocular morbidity and mortality.

We present an integrated filter on silicon photonics with wide free-spectral-range and sub-nm bandwidth, which is particularly suitable for programmable photonic circuit with arbitrary spectral responses. The unique feature is that its extinction ratio, namely the transmission coefficient within the bandwidth, can be independently controlled from 0 to 1 without affecting the rest optical span. Thus, a series of such building blocks with varying center wavelengths can be concentrated to form a programmable photonic circuit that can generate arbitrary spectral responses with easy control logic. The notch filter is a Mach–Zenhder-Interferometer with narrowband contra-directional couplers (CDC) and the filter performance is greatly enhanced compared with previous results. The bandwidth is reduced by a factor of 4 and the device length is only one third of previous demonstration.

This paper addresses the constructive interference (CI) precoding problem under per-antenna power constraint (PAPC) in the downlink of multi-user multiple-input single-output (MU-MISO) systems. In this setup, we extend the phase rotation metric and symbol scaling metric of CI precoding under sum power constraint (SPC) to the scenario of PAPC. Against SPC, the scenario of PAPC represents a practical constraint acknowledging that each antenna would have its dedicated power amplifier. Nevertheless, the optimization problem of CI-PAPC precoding becomes more challenging than that under SPC. By analyzing the KKT conditions and leveraging the generalized matrix inverse theory, we obtain a closed-form structure of the CI-PAPC precoder as a function of introduced variables, which facilitates a low-complexity solver. Since the power constraint of each antenna is not always active under PAPC, existing iterative schemes under CI-SPC are no longer applicable. Therefore, the primal-dual interior point method (IPM) is employed to solve the simplified problem with reduced complexity and fast convergence. Simulation results verify our mathematical derivations and demonstrate that our proposed method can reduce the complexity of solving CI-PAPC problem while preserving the error-rate performance, which promotes the practical implementation of CI precoding in real PAPC scenarios.

Pattern reconfigurable multiple-input multiple-output (PR-MIMO) can manipulate the wireless channel according to different communication requirements. In this paper, we discuss the potential of constructive interference (CI)-based symbol-level precoding (CI-SLP) in PR-MIMO communication systems. The joint design problem that optimizes the SLP strategy and the radiation pattern of PR-MIMO for phase-shift keying (PSK) modulation is formulated to maximize the worst serviced user’s communication quality. Since the optimization variables are softly-coupled, we employ the alternating optimization framework to decompose the joint design problem into the SLP design sub-problem and the pattern design sub-problem. We simplify the pattern design sub-problem and propose an interior-point algorithm, where a sequential optimization-based scheme is further proposed as a sub-optimal solution with low complexity. Furthermore, the discussion is extended to quadrature amplitude modulation (QAM) modulated systems, where a special stopping criterion is proposed to guarantee the performance gain of the proposed scheme. The practical realization of the designed reconfigurable antenna array is also discussed, where we propose a design scheme using programmable metasurface antennas based on time-division switching to enable quick and adaptive pattern reconfiguration. Numerical results demonstrate that the radiation pattern configurability can further enhance the benefit of SLP over conventional precoding approaches.

In this paper, we present an innovative symbol-level precoding (SLP) approach for a wideband multi-user multi-input multi-output (MU-MIMO) downlink integrated sensing and communications (ISAC) system employing faster-than-Nyquist (FTN) signaling. Our proposed technique minimizes the minimum mean squared error (MMSE) for the sensed parameter estimation while ensuring the communication per-user quality-of-service through the utilization of constructive interference (CI) methodologies. While the formulated problem is non-convex in general, we tackle this issue using proficient minorization and successive convex approximation (SCA) strategies. Numerical results substantiate that our FTN-ISAC-SLP framework can increase communication throughput by up to 20% while reducing sensing MMSE by about 1 dB.

This paper investigates the utilization of simultaneously transmitting and reflecting RIS (STAR-RIS) in supporting joint physical layer security (PLS) and covert communications (CCs) in a multi-antenna millimeter wave (mmWave) system, where the base station (BS) communicates with both covert and security users while defeating eavesdropping by wardens with the help of a STAR-RIS. Specifically, analytical derivations are performed to obtain the closed-form expression of warden’s minimum detection error probability (DEP). Furthermore, the asymptotic result of the minimum DEP and the lower bound of the secure rates are derived, considering the practical assumption that BS only knows the statistical channel state information (CSI) between STAR-RIS and the wardens. Subsequently, an optimization problem is formulated with the aim of maximizing the average sum of the covert rate and the minimum secure rate while ensuring the covert requirement and quality of service (QoS) for legal users by jointly optimizing the active and passive beamformers. Due to the strong coupling among variables, an iterative algorithm based on the alternating strategy and the semi-definite relaxation (SDR) method is proposed to solve the non-convex optimization problem. Simulation results indicate that the performance of the proposed STAR-RIS-assisted scheme greatly surpasses that of the conventional RIS scheme, which validates the superiority of STAR-RIS in simultaneously implementing PLS and CCs.

In this paper, we study the interference exploitation precoding in the presence of distortion from nonlinear power amplifiers (PAs) in multi-user multiple-input single-output (MU-MISO) downlink communication systems. We consider the memoryless polynomial model of nonlinear PAs, which is incorporated into the symbol-level precoding (SLP) design to allow the PA nonlinearities in the constructive interference (CI) exploitation. The optimization problem that aims to enhance the signal-to-interference-plus-noise ratio (SINR) without investing additional transmit signal power is formulated for both PSK and QAM signaling. Since the original optimization problem is nonconvex, we first introduce auxiliary variables to transform the optimization problem and adopt the alternating optimization framework for the new optimization problem. For non-convex subproblems, additional auxiliary variables are introduced and several approximations are employed to transform the problem into a semidefinite programming (SDP) form, where the semidefinite relaxation (SDR) method is adopted to obtain feasible solutions. In order to reduce the computational cost of the iterative algorithm, we further propose a low-complexity algorithm for the original PA-aware SLP optimization problem. Numerical results verify the superiority of our proposed PA-aware SLP approach in the presence of nonlinear PAs in the MU-MISO downlink in terms of the error-rate performance over the state-of-the-art.

Gatemon qubits are the electrically tunable cousins of superconducting transmon qubits. In this work, we demonstrate the full coherent control of a gatemon qubit based on hole carriers in a Ge/Si core/shell nanowire, with the longest coherence times in group IV material gatemons to date. The key to these results is a high-quality Josephson junction obtained using a straightforward and reproducible annealing technique. We demonstrate that the transport through the narrow junction is dominated by only two quantum channels, with transparencies up to unity. This novel qubit platform holds great promise for quantum information applications, not only because it incorporates technologically relevant materials, but also because it provides new opportunities, like an ultrastrong spin–orbit coupling in the few-channel regime of Josephson junctions.

To reconcile the contradictory wettability requirements for the reduction and oxidation half-reactions in overall CO2photoreduction, an alternately hydrophobic catalyst is constructed through selectively hydrophobic modification and a charge-carrier-guided strategy.

When shield tunneling is performed in water-rich silt and fine sand strata, the grout becomes runny when diluted by groundwater. After dilution, the filling effect of the grout is not significant, and the level of surface settlement is very high. In this study, based on bidding section 04 of Tianjin Metro Line 11, traditional grouting materials were selected to conduct response surface method (RSM) tests. The purposes of the RSM analysis were to analyze the interactions between materials and their influences on grout performance and to optimize the grout mix ratio. Various admixtures were compared to assess the effects of different admixtures and compositions on the dispersion resistance and flow performance of the grout. Finally, a shield synchronous grouting test system was developed, and a similar indoor grouting simulation test was performed to analyze the influences of the different admixtures on the filling effects and to determine a reasonable grout mix ratio. The following three results were obtained. (1) The RSM was suitable for grout performance prediction and grout mix ratio optimization, and hydroxyethyl cellulose could improve the grout performance and increase the bond performance between the cementing material and aggregate. (2) Admixture incorporation enhancement could improve the grout utilization rate and increase the diffusion distance at the top of the tunnel, which would be conducive to filling the gap at the tail end of the shield. (3) The optimal preparation scheme of grout in water-rich fine sand formations included a water–binder ratio of 0.72, cement–sand ratio of 0.80, fly ash content of 5%, bentonite content of 14.94%, and admixture content of 0.8%–0.9%

RNA N6-methyladenosine (m6A), as the most abundant modification of messenger RNA, can modulate insect behaviors, but its specific roles in aggregation behaviors remain unexplored. Here, we conducted a comprehensive molecular and physiological characterization of the individual components of the methyltransferase and demethylase in the migratory locust Locusta migratoria. Our results demonstrated that METTL3, METTL14and ALKBH5were dominantly expressed in the brain and exhibited remarkable responses to crowding or isolation. The individual knockdown of methyltransferases (i.e., METTL3and METTL14) promoted locust movement and conspecific attraction, whereas ALKBH5knockdown induced a behavioral shift toward the solitary phase. Furthermore, global transcriptome profiles revealed that m6A modification could regulate the orchestration of gene expression to fine tune the behavioral aggregation of locusts. In summary, our in vivocharacterization of the m6A functions in migratory locusts clearly demonstrated the crucial roles of the m6A pathway in effectively modulating aggregation behaviors.

High-temperature annealing is widely recognized as an effective way to improve the durability of Pt/C cathode catalysts used in proton exchange membrane fuel cells (PEMFCs), yet systematic studies on its effects on PEMFC performance are still lacking. Herein, we explore the effect of high-temperature annealing on the PEMFC performance, based on a thorough comparative analysis of Pt/C catalysts annealed at temperatures ranging from 500–900°C. Our results reveal that high-temperature annealing not only enhances the catalyst durability but also substantially increases Pt utilization, which in turn drives the increase in mass activity and the enhancement of low-current-density performance. Based on an array of electrochemical and physical characterization results, we infer that the increased utilization of Pt might stem from nanoparticle migration induced by high-temperature annealing, leading to closer proximity between Pt nanoparticles and ionomers. This reduced distance potentially enhances the accessibility of protons to the Pt nanoparticles, thereby improving the Pt utilization.

The hierarchical porous lattice implant with microscopic porosity, which resembles the original human bone structure, has significant potential application value. The microscopic porosity in the hierarchical porous lattice implant plays a crucial role in transporting nutrients and promoting tissue regeneration. However, it is difficult to fabricate microscopic pores smaller than 200 μm by powder bed fusion (PBF) processes due to the limitations of the laser spot size. In this study, the preparation of a hierarchical porous lattice implant with microscopic porosity is proposed by coupling structure design with the high scanning speed - short hatch spacing (HSSH) process formation. The structure-versus-process relationship is used to control the size and distribution of the microscopic pores, which meets the requirements of modulus and high biocompatibility. This proposed process breaks the inherent law where the higher the porosity, the higher the modulus of the lattice for the same lattice type. The modulus and porosity of the hierarchical porous implants could be flexibly tuned over a wide range (0.1–1.8 GPa and 63–84 %, respectively). The microscopic porosity is mainly distributed near the contour of the core rod, and the macroscopic porosity and microscopic porosity are approximately 73.70 % and 8.22 %, respectively. The problem of large errors in fitting the hierarchical porous lattice modulus calculation model according to the Gibson-Ashby equation has been solved. The mechanism of microscopic porosity formation was also analyzed. Furthermore, this method has the advantage of universal applicability, providing a feasible way for the development and application of porous materials.

Closed pores play a crucial role in improving the low-voltage (<0.1 V) plateau capacity of hard carbon anodes for sodium-ion batteries (SIBs). However, the lack of simple and effective closed-pore construction strategies, as well as the unclear closed-pore formation mechanism, has severely hindered the development of high plateau capacity hard carbon anodes. Herein, we present an effective closed-pore construction strategy by one-step pyrolysis of zinc gluconate (ZG) and elucidate the corresponding mechanism of closed-pore formation. The closed-pore formation mechanism during the pyrolysis of ZG mainly involves (i) the precipitation of ZnO nanoparticles and the ZnO etching on carbon under 1100 °C to generate open pores of 0.45–4 nm and (ii) the development of graphitic domains and the shrinkage of the partial open pores at 1100–1500 °C to convert the open pores to closed pores. Benefiting from the considerable closed-pore content and suitable microstructure, the optimized hard carbon achieves an ultrahigh reversible specific capacity of 481.5 mA h g–1and an extraordinary plateau capacity of 389 mA h g–1for use as the anode of SIBs. Additionally, some in situ and ex situ characterizations demonstrate that the high-voltage slope capacity and the low-voltage plateau capacity stem from the adsorption of Na+at the defect sites and Na-cluster formation in closed pores, respectively.

On Earth, high-speed rotating blades and rotors experience hypergravity, which is mainly derived from centrifugal force. Aluminum alloys are widely used in high-speed rotating machines. In particular, 7075 aluminum has excellent properties, providing it with great potential for application in high-temperature rotating parts. In this work, the cracking behavior and microstructural evolution characteristics of high-speed rotating blades under different stresses were studied. A specifically designed instrument and blades with multiple necks were assembled, and the stress was tuned by adding weight to the blade tip. Each rotating blade cracked on its root neck, indicating that the gradient hypergravitational force decreased from the root to the tip. The degree of high-temperature cracking obviously increased with a sawtooth-like tip, but the degree of low-temperature cracking did not obviously increase with a smooth tip. A comparison under a constant uniaxial force required a greatly increased ultimate cracking strength that was approximately 10–18 times greater than that under hypergravitational force at the same temperature. Force analysis indicated that the coupling of hypergravitational forces in the normal direction and torsional forces in the tangential direction accelerated cracking. A uniaxial force caused grains to extend along the blade direction. However, a tangential force cut these extended grains to accelerate cracking and grain refining. In this study, real-world simulated service conditions for commercial alloys rotating at high speeds and a new understanding of the mechanical properties of alloys under various severe conditions were provided.

A 38-year-old male patient was diagnosed as acute non-ST-segment elevation myocardial infarction on Apr 21st 2021 and he received percutaneous transluminal coronary angioplasty for RCA via transradial artery access. He sought for second percutaneous coronary intervention in our center for frequently exertional angina on Sep 13th 2021. Proximal right radial artery pulsation can not be touched in physical examination, indicating right radial artery occlusion (RAO). Distal transradial access was applied and RAO was confirmed via angiography. With balloon pre-dilation, the guidewire and guiding catheter crossed the occlusion and coronary intervention was successfully completed. A Reewarm 2.5 × 220 mm paclitaxel drug-coated balloon (Endovastec, China) was released at 12 atm in radial arterial lesion with 90 s. Pulsation of radial artery can be well palpated 24 h after PCI. No oral anticoagulant was added. The right radial artery remained patent after 8-month and 14-month follow-up and there was no abnormal sensation or obstacle of right hand.

AbstractFacility location and resource allocation play an essential role in the operational management of mobile health clinics (MHCs) as optimization of both can help medical service providers improve their service coverage under limited resources. In this paper, we consider the issue of maximizing the coverage of immunization services provided by MHCs in vulnerable communities such as school zones and census tracts. Since demand in communities overlaps with neighboring communities, this leads to the so-called mobile facility location with overlapped demand (MFL-OD). To capture the overlapped demand in different communities, we introduce a novel integer programming model with linear and bilinear constraints (BLCIP) and show that the BLCIP model is NP-hard. A polynomial-time approximation algorithm is proposed for the BLCIP, and the approximation ratio of the obtained solution is estimated. We implement the proposed model and approximation algorithm for a case study in the Houston Independent School District and its associated communities. Preliminary experiments demonstrate the efficacy of the proposed model and the efficiency of the proposed approximation method.

Ferromagnetic (FM) semiconductors combine the advantages of semiconductors (e.g., logic devices) and magnetic materials (e.g., memories) and have garnered increasing amounts of attention for more than half a century. However, the development of FM semiconductors faces challenges due to the scarcity of suitable candidates and their low Curie temperature. Traditionally, ferromagnetism is observed in transition metal compounds with octahedral coordination. In contrast, tetrahedral coordination compounds, with smaller crystal field splitting and weaker antiferromagnetic (AFM) direct exchange, hold promise as potential candidates for high-temperature ferromagnets but remain largely unexplored. In this work, we propose that high-temperature FM semiconductors can be realized in tetrahedral coordination superlattices (SLs). On the basis of first-principles calculations, we systematically investigated a series of MX/TMX (MX denotes group 12–16, 13–15 or 14–14 tetrahedral semiconductors, TM denotes a 3d transition metal, X denotes the ligand) SL. Among them, SiC/CrC SL emerges as a stable FM semiconductor with an indirect band gap of 0.363 eV and a high Curie temperature (TC) of ∼935 K. Furthermore, the distributions of the Cr atomic layer and interlayer magnetic couplings are explored. A uniaxial-pressure-induced AFM-to-FM phase transition is predicted. These discoveries present novel opportunities for realizing high-temperature FM semiconductors in tetrahedral coordination SLs, offering potential advancements in future spintronic applications.

To simultaneously yield superior evaporation rate and output voltage in solar-driven interfacial evaporators, the synergetic integration of phase change materials and photothermal materials in 3D interfacial evaporators has been proposed. This integration strategy provides additional insights for exploring next-generation solar-driven power generation and water evaporation devices.

Atomic structure prediction and associated property calculations are the bedrock of chemical physics. Since high-fidelity ab initio modeling techniques for computing the structure and properties can be prohibitively expensive, this motivates the development of machine-learning (ML) models that make these predictions more efficiently. Training graph neural networks over large atomistic databases introduces unique computational challenges, such as the need to process millions of small graphs with variable size and support communication patterns that are distinct from learning over large graphs, such as social networks. We demonstrate a novel hardware–software codesign approach to scale up the training of atomistic graph neural networks (GNN) for structure and property prediction. First, to eliminate redundant computation and memory associated with alternative padding techniques and to improve throughput via minimizing communication, we formulate the effective coalescing of the batches of variable-size atomistic graphs as the bin packing problem and introduce a hardware-agnostic algorithm to pack these batches. In addition, we propose hardware-specific optimizations, including a planner and vectorization for the gather-scatter operations targeted for Graphcore’s Intelligence Processing Unit (IPU), as well as model-specific optimizations such as merged communication collectives and optimized softplus. Putting these all together, we demonstrate the effectiveness of the proposed codesign approach by providing an implementation of a well-established atomistic GNN on the Graphcore IPUs. We evaluate the training performance on multiple atomistic graph databases with varying degrees of graph counts, sizes, and sparsity. We demonstrate that such a codesign approach can reduce the training time of atomistic GNNs and can improve their performance by up to 1.5× compared to the baseline implementation of the model on the IPUs. Additionally, we compare our IPU implementation with a Nvidia GPU-based implementation and show that our atomistic GNN implementation on the IPUs can run 1.8× faster on average compared to the execution time on the GPUs.

Oxidation is one of the main failure modes of superalloys, and the initial oxidation of a superalloy provides clues for its failure analysis. NiCo-based superalloys exhibit superior mechanical properties, but their oxidation behaviour is still debatable, especially in terms of the ratio of Ni/Co. Here, we show the effect of the Ni/Co ratio on the initial oxidation behaviour at the nanoscale by in situenvironmental transmission electron microscopy (ETEM), which provides the initial microstructural changes in the γ/γ′ structure-based alloy. The results indicate that Ni-rich alloys exhibit better structural stability at high temperatures than Ni-deficient alloys. A high content of Ni promotes the formation of a dense oxide layer, inhibits the oxidation rate, and improves the oxidation resistance. This result will help to elucidate the basic process of oxide formation in NiCo-based single-crystal superalloys and provide ideas for improving their oxidation resistance for alloy design.

Ferromagnetic (FM) semiconductors with intrinsic spontaneous net magnetizations and semiconductivity show great potential in future spintronic applications such as low-energy-cost random access memories. However, room-temperature FM semiconductors have not yet been discovered, which hinders their practical applications. In this work, using first-principles calculations, we show that Curie temperature (TC) of the conventional FM semiconducting spinels ACr2X4(A = Cd, Zn, Hg; X = S, Se, Te) can be significantly increased via partially replacing the Cr by W ions. The alloyed structures of ACr1.5W0.5X4are predicted to be intrinsic room-temperature FM semiconductors with diverse electronic bandgaps. Among them, CdCr1.5W0.5Se4shows TCof ∼310 K, which is more than doubled that (∼150 K) of the pristine CdCr2Se4. These findings provide a new route to realize room-temperature FM semiconductors, which will be of great interest for the development of spintronics.