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Relaxor ferroelectrics exhibit giant potentials in capacitive energy storage, however, the scales of polar nanoregions determine the critical field values where the polarization saturation occurs. In this work, a mesoscopic structure engineered ergodic relaxor state is realized by adjusting submicron‐grain scaled chemical homogenity, exhibiting polymorphic polar nanoregions of various scales in different grains. This produces a relatively continuous polarization switching with increasing the applied electric field from diverse grains, thus resulting in a linear‐like polarization response feature. As a result, both a giant energy density (Wrec) ≈15.4 J cm−3 and a field‐insensitive ultrahigh efficiency (η) ≈93.2% are simultaneously achieved at 78 kV mm−1 in (Ba, Ca)(Ti, Zr)O3‐(Bi0.5Na0.5)SnO3 lead‐free ceramics. Moreover, both the mesoscopic structure heterogeneity and complex high internal stresses in ultrafine grains decrease the temperature sensitivity of the nanodomain structural features. Together with the suppressed high‐temperature defect motion from high ceramic density and submicron grain size, a record‐high temperature stability with Wrec = 10.4±5% J cm−3 and η = 96±3% is obtained at 65 kV mm−1 and 0–250 °C, demonstrating great application potential of the studied ceramic in high‐temperature energy storage capacitors. The proposed strategy in this work greatly expands the design mentality for next‐generation high‐performance energy‐storage dielectrics. BaTiO3‐based polymorphic relaxor ferroelectrics are engineered by mesoscopically chemical homogeneity, constructing diversified nanodomain architectures with similar multiple local symmetries but different nanodomain scales in diverse grains. Ex‐/In situ multiscale structure analysis indicates that a relatively continuous polarization switching with increasing the applied electric field from the diverse grains is responsible for the superior energy‐storage properties.

Bentonite pellets are recognized as good buffer/backfill materials for sealing technological voids in high-level radioactive waste (HLW) repository. Compared to that of a traditional compacted bentonite block, one of the most important particularities of this material is the initially discrete pellets and the inevitable heterogeneous porosity formed, leading to a distinctive water retention behaviour. In this paper, water retention and mercury intrusion porosimetry (MIP) tests were conducted on pellet mixture (constant volume), single pellet (free swelling) and compacted block (constant volume) of GMZ bentonite, water retention properties and pore structure evolutions of the specimens were comparatively investigated. Results show that the water retention properties of the three specimens are almost similar to each other in the high suction range (> 10 MPa), while the water retention capacity of pellet mixture is lower than those of the compacted block and single pellet in the low suction range (< 10 MPa). Based on the capillary water retention theory (the Young–Laplace equation), a new concept ‘saturated void ratio’ that was positively related to water content and dependent on pore size distribution of the specimen was defined. Then, according to the product of saturated void ratio and water density in saturated void, differences of water retention properties for the three specimens at low suctions were explained. Meanwhile, MIP tests indicate that as suction decreases, the micro- and macrovoid ratios of pellet mixture and compacted block decrease as the mesovoid ratio increases, while all the void ratios of single pellets increase. This could be explained that upon wetting, water is successively adsorbed into the inter-layer, inter-particle and inter-pellet voids, leading to the subdivision of particles and swelling of aggregates and pellets. Under constant volume condition, aggregates and pellets tend to swell and fill into the inter-aggregates or inter-pellets voids. While under free swelling condition, the particles and aggregates in a single pellet tend to swell outward rather than squeezing into the inter-aggregate voids, leading to the expansion of the pores and even formation of cracks. Results including the effects of initial conditions (initial dry density and fabric) and constraint conditions (constant volume or free swelling) on the water retention capacity and pore structure evolution reached in this work are of great importance in designing of engineering barrier systems for the HLW repository.

Bismuth-based materials have attracted broad research interest as catalysts for electrocatalytic CO 2 reduction (ECR) to formate in recent years. Most studies have been focused on exploring materials with high activity, selectivity, and durability, while little attention has been paid to the catalysts structure stability especially under working conditions of CO 2 electrolysis. Here, starting from the precursor of bismuth oxide formate nanowires (BiOCOOH NWs), it was found that BiOCOOH NWs were easy to electrochemically evolve into two-dimensional sheet structure in CO 2 -saturated KHCO 3 solution and would further reconstitute into larger ultrathin bismuth nanosheets covered with amorphous oxide thin layer (Bi/BiO x NSs). However, in Ar-saturated HCOONa solution, the one-dimensional structure could be maintained and reconstructed into rough porous bismuth nanowires (Bi NWs). Bi NWs showed less stability during ECR, which also generated surface amorphous oxide layer and further fragmentated into nanoparticles or nanosheets. Bi/BiO x NSs showed better activity, selectivity, and stability than Bi NWs, thanks to the high exposing active sites, enhancing CO 2 adsorption and charge transfer. The demonstrated electrolyte dependence of structure evolution for bismuth-based catalysts and their performance for CO 2 electroreduction could provide guidance for the design and synthesis of efficient catalysts.

2024 aluminum alloy is widely used because of its high strength, low density, strong corrosion resistance, good heat resistance, light material and other excellent properties. However, in the ultra-precision machining process, its crystal structure often changes due to tool extrusion, resulting in changes in its physical properties such as plasticity and adhesion, which seriously affects the machining quality and tool wear. At present, aluminum alloy cutting is mainly carried out by cemented carbide tools. In this paper, the simulation experiment of WC tool cutting 2024 aluminum alloy is carried out based on MD (molecular dynamics) simulation method. The CNA (common neighbor analysis), DXA (dislocation analysis) and Coordination (coordination analysis) methods are used to study the tool diffusion wear mechanism and the influence of crystal evolution on tool diffusion wear based on the change of cutting parameters from the microscopic point of view. The results show that diffusion wear is the main factor causing WC tool wear. The defect evolution of the workpiece during the cutting process will directly affect the cutting force and cutting temperature, thus affecting the diffusion wear of the tool. The cutting speed, cutting width, cutting depth and tool clearance angle have a regular effect on the defect evolution of workpiece atoms and the order degree of tool atoms in the cutting process. At the same time, this paper verifies the correctness of the simulation results through milling experiments. The research results based on molecular dynamics simulation are reliable, which can greatly reduce the test cost and improve the efficiency of scientific research. It provides a reference for further improving the surface quality of ultra-precision cutting of aluminum-based alloy materials and reducing tool wear.

Rechargeable lithium‐ion and sodium‐ion batteries (SIB) have dominated the energy storage fields such as electric vehicles and portable electronics due to their high energy density, long cycle life, and environmental friendliness. However, the critical bottleneck hindering the further improvement of their electrochemical performance is the unsatisfactory cathode materials, typically exhibiting inherent drawbacks such as low reversible capacity, initial capacity loss, fast capacity decay, and poor rate performance. These issues are mainly attributed to changes in the internal structure of cathode materials, such as irreversible transformation of particle morphology, evolution of crystal structure, and undesired physicochemical interfacial reactions during the electrochemical process. To address above obstacles, abundant research efforts have been devoted to stabilizing the structural evolution of cathode materials and enhancing their electrochemical performance. Herein, we reviewed the research progress on the cathode materials for lithium‐ion and SIBs. The typical cathodes and their structural characteristics, electrochemical behaviors, reaction mechanisms, and strategies for electrochemical performance optimization were summarized. This review aims to promote the understanding of the structure‐performance relationship in the cathode materials and provide some guidance for the design of advanced cathode materials for lithium‐ion and SIBs from the perspective of crystal structure. We review structure‐performance relationship in the cathode materials in this article. The typical cathodes and their structural characteristics, electrochemical behaviors, reaction mechanisms, and strategies for electrochemical performance optimization are introduced, followed by outlooks of future rational design.

Understanding the dynamic structural and chemical evolutions at the catalyst–electrolyte interfaces is crucial for the development of active and stable electrocatalysts. In this work, β-Li 2 IrO 3 is employed as a model catalyst for the oxygen evolution reaction (OER). Its elastic three-dimensional Ir-O framework enables us to investigate the Li + cation dissolution-induced structure evolutions and the formation mechanism of amorphous IrO x species. Electrochemical measurements by rotating ring disk electrode (RRDE) reveal that up to 60% of the measured OER current can be ascribed to catalyst degradation. A series of in-situ X-ray diffraction spectroscopy (XRD), X-ray absorption spectroscopy (XAS), and Raman spectroscopy are conducted. Structure vibration is observed with oxidation states of Ir being reduced abnormally during OER at high potentials. It’s hypothesized that the reversible proton intercalations are responsible for the Ir turn-over mechanism. Results of this work demonstrate a stable and elastic iridate structure and reveal the initial catalyst degradation behaviors during OER in acid media.

The molecular clock hypothesis, which states that substitutions accumulate in protein sequences at a constant rate, plays a fundamental role in molecular evolution but it is violated when selective or mutational processes vary with time. Such violations of the molecular clock have been widely investigated for protein sequences, but not yet for protein structures. Here, we introduce a novel statistical test (Significant Clock Violations) and performa large scale assessment of the molecular clock in the evolution of both protein sequences and structures in three large superfamilies. After validating our method with computer simulations, we find that clock violations are generally consistent in sequence and structure evolution, but they tend to be larger and more significant in structure evolution. Moreover, changes of function assessed through Gene Ontology and InterPro terms are associated with large and significant clock violations in structure evolution. We found that almost one third of significant clock violations are significant in structure evolution but not in sequence evolution, highlighting the advantage to use structure information for assessing accelerated evolution and gathering hints of positive selection. Clock violations between closely related pairs are frequently significant in sequence evolution, consistent with the observed time dependence of the substitution rate attributed to segregation of neutral and slightly deleterious polymorphisms, but not in structure evolution, suggesting that these substitutions do not affect protein structure although they may affect stability. These results are consistent with the view that natural selection, both negative and positive, constrains more strongly protein structures than protein sequences. Our code for computing clock violations is freely available at https://github.com/ugobas/Molecular_clock.

The targeted stimulation of micropores based on the transformation of coal’s molecular structure is proposed due to the chemical properties and difficult-to-transform properties of micropores. Carbon disulfide (CS2) extraction is used as a targeted stimulation to reveal the internal evolution mechanism of micropore transformation. The variations of microcrystalline structures and micropores of bituminous coal and anthracite extracted by CS2 were analyzed with X-ray diffraction (XRD), low-temperature carbon dioxide (CO2) adsorption, and molecular simulation. The results show that CS2 extraction, with the broken chain effect, swelling effect, and aromatic ring rearrangement effect, can promote micropore generation of bituminous coal by transforming the microcrystalline structure. Furthermore, CS2 extraction on bituminous coal can decrease the average micropore size and increase the micropore volume and area. The aromatic layer fragmentation effect of CS2 extraction on anthracite, compared to the micropore generation effect of the broken chain effect and swelling effect, can enlarge micropores more remarkably, as it induces an enhancement in the average micropore size and a decline in the micropore volume and area. The research is expected to provide a theoretical basis for establishing reservoir stimulation technology based on CS2 extraction.

Understanding pore structure evolution in lacustrine shale systems provides critical insights for marine shale reservoir characterization. This study presents an integrated petrological and petrophysical analysis of a representative lacustrine shale succession, employing low temperature nitrogen adsorption (LTNA), whole rock X-ray diffraction (XRD), and scanning electron microscopy (SEM). The study shows that (1) Clay-dominated pore systems evolve through distinct pathways compared to marine shales, with illite/smectite mixed-layer minerals generating abundant mesopores through diagenetic transformation. (2) Organic matter- dominated pores display limited connectivity due to Type III kerogen characteristics and hydrocarbon generation-induced pore occlusion, contrasting with marine shale systems dominated by Type II kerogen. (3) Comparative analysis demonstrates that lacustrine shales preserve 30–40% higher micro-mesopore volumes than their marine counterparts under similar thermal maturity conditions, attributed to enhanced clay mineral diagenesis in freshwater environments. These findings provide a new framework for understanding pore structure development in non-marine depositional systems and provide valuable analogs for marine shale reservoir evaluation, particularly in transitional marine-lacustrine basins.

To investigate the mitochondrial genome characteristics and evolutionary dynamics of Lagerstroemia suprareticulata , we performed complete assembly and annotation of its mitochondrial genome, followed by comparative genomic analyses with related species. This research presents the initial comprehensive mitogenome of L. suprareticulata , a 364,645 bp independent single cyclic structure with a whole average GC content of 46.20%, twice the size of the chloroplast genome and an approximately similar tetrad structure. It comprised 62 functional genes and 386 open reading frames. Besides two long repeats above 800 bp, simple sequence repeat analysis revealed a predominance of mono-nucleotide and tetra-nucleotide repeats, which is consistent with patterns observed in most Lythraceae species. A total of 480 C-to-U RNA editing sites were predicted in 36 protein-coding genes, with the highest number in nad4 . AUG and UGG had a relative synonymous codon usage value of 1, while GCU had the highest RSCU (1.62). ccmB and rps4 may have undergone positive selection, whereas atp8 and cox1 experienced strong purifying selection. Phylogenetic analysis based on mitochondrial and chloroplast genomes confirmed a close relationship between L. suprareticulata and L. indica . Collinear segments decreased with increasing evolutionary distance, and gene rearrangement analysis revealed a lineage-specific gene arrangement pattern in Lagerstroemia . Homologous sequence analysis identified 34 mitochondrial-chloroplast homologous sequences (accounting for 4.63% of the mitochondrial genome) and 2182 mitochondrial-nuclear homologous sequences. These results provide a foundation for understanding the mitochondrial genome evolution of Lagerstroemia and Lythraceae, and may offer valuable genetic resources for horticultural and evolutionary studies.