Temperature Stability Research Articles

Legacies of millennial-scale climate oscillations in contemporary biodiversity in eastern North America.

The Atlantic meridional overturning circulation (AMOC) has caused significant climate changes over the past 90 000 years. Prior work has hypothesized that these millennial-scale climate variations effected past and contemporary biodiversity, but the effects are understudied. Moreover, few biogeographic models have accounted for uncertainties in palaeoclimatic simulations of millennial-scale variability. We examine whether refuges from millennial-scale climate oscillations have left detectable legacies in the patterns of contemporary species richness in eastern North America. We analyse 13 palaeoclimate estimates from climate simulations and proxy-based reconstructions as predictors for the contemporary richness of amphibians, passerine birds, mammals, reptiles and trees. Results suggest that past climate changes owing to AMOC variations have left weak but detectable imprints on the contemporary richness of mammals and trees. High temperature stability, precipitation increase, and an apparent climate fulcrum in the southeastern United States across millennial-scale climate oscillations aligns with high biodiversity in the region. These findings support the hypothesis that the southeastern United States may have acted as a biodiversity refuge. However, for some taxa, the strength and direction of palaeoclimate-richness relationships varies among different palaeoclimate estimates, pointing to the importance of palaeoclimatic ensembles and the need for caution when basing biogeographic interpretations on individual palaeoclimate simulations. This article is part of the theme issue 'Ecological novelty and planetary stewardship: biodiversity dynamics in a transforming biosphere'.

Achieving temperature stability for storage of biological samples in an autodefrost freezer.

To assess the temperature stability of an autodefrost freezer commonly used in veterinary practices, whether the use of a Styrofoam cooler within the freezer provides temperature stability, and the ease of use of a remote monitoring system for the notification of temperature elevations. None. Temperature in the freezer and 2 Styrofoam coolers were assessed with remote monitoring thermometers every 15 minutes. Temperature values were monitored from October 11 to December 18, 2023 (for a 68-day period). Data analysis focused on temperatures for the freezer exceeding 0 °C and the elevations in temperatures within the coolers relative to the freezer. The freezer had an increase in temperature approximately every 16 hours. Over 68 days, the freezer had a temperature greater than 0 °C 27 times, representing 26 separate elevations. The Styrofoam coolers within the freezer never registered a temperature higher than -5 °C. Elevations in temperature within the freezer were larger in magnitude than temperature elevations within the coolers, which showed smaller-magnitude changes in temperature. The temperature stability provided by the Styrofoam cooler would avoid potential freeze-thaw cycles of any stored biological samples. Additionally, the remote temperature monitoring system is easy to install and monitor, providing peace of mind to practice management.

Influence of electrophoretic deposition of micro- or nanosized silica particles on the microstructure of carbon fibers and their bond behavior with cementitious matrices

The application of carbon fiber (CF) reinforced cementitious composites is often restricted by the poor load transfer between the components. In this study, two reactive coating materials—nano-silica and micro-silica—are utilized to modify the CF surfaces via an electrophoretic deposition approach. These negatively charged particles are able to be electrosorbed onto the fiber surfaces under a constant electrical field according to the zeta and cyclic voltammetry measurements. After surface treatment, XRD analysis of CFs showed an increase in graphite crystallite thickness and decrement in interlayer spacing d002\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${d}_{002}$$\\end{document}, significantly affecting the fiber diameters. Additionally, the lengths of crystallites were reduced, which can impair the fiber strength and their temperature stability. Single fiber pullout tests exhibited that the interfacial bonding can be clearly enhanced by both reactive coatings. Microscopic observation revealed that C–S–H gel and calcite structures can be formed near the fiber surfaces after immersion in cement pore solution owing to pozzolanic reaction and nucleation effect, tremendously heightening both chemical and mechanical interaction between fiber and cement. Finally, based on a detailed micromechanical analysis, the reinforcing mechanisms between the differently modified fibers and the cementitious matrix were elaborated and discussed.Graphical abstract

Binary Nematic Liquid Crystals Mixture with Enhanced Electro-Optics Properties for Photonic Applications

Purpose: In this work, we mix two simple nematic liquid crystals (NLCs) and investigated the binaryNLCs mixtures of 7CB/PCH5 of different mixing ratios. Methodology: The pure liquid crystals 7CB and PCH5 and binary mixtures of them of high temperature stability were thermally analyzed by differential scanning calorimetry. The mixture 7CB/PCH5:30/70 wt% has the highest thermal stability with a nematic-isotropic (N-I) transition temperature at 50oC. The electrooptic properties of 7CB, PCH5, and the mixture 7CB/PCH5:30/70 wt% at room temperature were also investigated using an amplitude modulated electric signal (1 kHz - 100 Hz) by increasing diving peak voltage from 0 V to 10 V. The threshold volage is relatively reduced for the binary mixture in comparison to that value for PCH5. In comparison to the pure LCs, the mixture 7CB/PCH5:30/70 wt% has the fastest response times of values 2.36 ms total time response, 0.41 ms rise time, and 1.95 ms fall time. It has also the highest contrast ratio. Moreover, it has a maximum measured transmission that is higher than those for PCH5 and 7CB by about 17 % and 8%, respectively, at a field strength of 2V/mm. Findings: The obtained results indicate that the electrooptic properties of PCH5 was improved when mixed with a proper ratio of 7CB, of lower cost, more stablity , and higher potential for photonic applications. Unique Contriburibution to Theory, Practice and Policy: This expermental study shows that simply by mixing two relatively low cost NLCs materials, one of high thermal stability and low electro-optic properties with other one of low thermal stability and better electro-optic properties; this would improve the stability, response, and transmition of the binary mixture. If the a suitable driving method is applied, without doping with other orgnic or inorganic matrial.

Thermoelectric active cooling for transient hot spots in microprocessors

Modern microprocessor performance is limited by local hot spots induced at high frequency by busy integrated circuit elements such as the clock generator. Locally embedded thermoelectric devices (TEDs) are proposed to perform active cooling whereby thermoelectric effects enhance passive cooling by the Fourier law in removing heat from the hot spot to colder regions. To mitigate transient heating events and improve temperature stability, we propose a novel analytical solution that describes the temperature response of a periodically heated hot spot that is actively cooled by a TED driven electrically at the same frequency. The analytical solution that we present is validated by experimental data from frequency domain thermal reflectance (FDTR) measurements made directly on an actively cooled Si thermoelectric device where the pump laser replicates the transient hot spot. We herein demonstrate a practical method to actively cancel the transient temperature variations on circuit elements with TEDs. This result opens a new path to optimize the design of cooling systems for transient localized hot spots in integrated circuits.

Various graded index plastic optical fiber performance signature capability with the optimum dispersion control for indoor coverage applications

Abstract This work has clarified the various graded index plastic optical fiber performance signature with the optimum dispersion control for indoor coverage applications. The plastic optical fibers that are deeply employed namely Polymethyl mathacrylate (PMMA), Epoxy, Polyfluorene and Cyclotene. Various plastic optical fiber dispersion is demonstrated against temperature variations. The different plastic fibers pulse broadening is clarified versus temperature variations. The previous plastic optical fibers types with respect to refractive index configuration and number of modes are clarified. Previous studies on PMMA/CYTOP plastic optical fibers attenuation is clarified against wavelength band variations. Various transmission techniques are applied to measure the fiber bandwidth and fiber channel bit rate. These transmission techniques are MTDM, NRZ and RZ coding. Different plastic fiber bandwidth against fiber channel distance is demonstrated based on NRZ, RZ and MTDM coding at room temperature. Different plastic fiber channel bit rate against fiber channel distance is studied and clarified based on NRZ, RZ and MTDM coding at room temperature. The choice of these plastic fibers are high temperature stability and more flexibility/reliability than other plastic fibers. The dispersion of these proposed plastic fibers can be controlled and managed with the control of temperature variations.

High‐entropy strategies boosting dielectric temperature stability in (Na0.4K0.1Bi0.5)TiO3 ceramics

AbstractUtilizing a high‐entropy strategy, we propose a novel approach for synthesizing (Na0.4K0.1Bi0.5)TiO3 (NKBT)‐based ceramics endowed with exceptional dielectric stability at elevated temperatures. The high‐entropy effect induces a random tilt in the oxygen octahedra of NKBT ceramics, leading to a broad dielectric response characterized by diffuse phase transitions. By weakening the dielectric abnormal peak at Ts of BNT, the dielectric stability of high‐entropy NKBT ceramics is significantly enhanced. Notably, at 100 kHz, the temperature stability range of (Na0.4K0.1Bi0.5)(Ti0.65Zr0.1Sn0.15Hf0.1)O3, synthesized through the traditional solid reaction method, reaches an impressive 311°C, surpassing undoped NKBT by 257%. This significant enhancement underscores the feasibility of our high‐entropy strategy in improving dielectric performance. Our work demonstrates a straightforward and cost‐effective method for significantly improving the dielectric temperature stability of NKBT ceramics.

Influence of Li‐Stoichiometry on Electrical and Acoustic Properties and Temperature Stability of Li(Nb,Ta)O3 Solid Solutions up to 900 °C

The current work is focused on the impact of the lithium stoichiometry on electrical conductivity, acoustic properties, and high‐temperature stability of single crystalline Li(Nb,Ta)O3 at high temperatures. The crystals grown from Li‐deficient melts are treated by the vapor transport equilibration (VTE) method, achieving near stoichiometric Li‐content. It is shown that the VTE‐treated specimens generally exhibit lower conductivity at temperatures below 800 °C, which is attributed to the reduced number of Li‐vacancies in near stoichiometric Li(Nb,Ta)O3, provided that the Li‐ion migration dominates the conductivity in this temperature range. Further, it is shown that above 600–650 °C different mechanism increasingly contributes to the conductivity, which is consequently attributed to the electronic conduction. Further, it is shown that losses in LNT strongly increase above about 500 °C, which is interpreted to originate from conductivity‐related relaxation mechanism. Finally, the thermal stability of Li(Nb,Ta)O3 is evaluated by the measurement of the conductivity and resonance frequency as a function of time. It is found that during annealing at 700 °C for 350 h, the resonance frequency of LiNbO3 remains in a ± 100 ppm range of the initial value of 3.5 MHz.

Coal gangue in asphalt pavement: A review of applications and performance influence

The comprehensive utilization of coal gangue is low, and this causes serious environment problems and security risks. The physical and chemical properties of coal gangue were analyzed in this paper, and the estimated value of different chemical components of coal gangue was counted. The physical properties of coal gangue aggregate were analyzed, and performance and its influencing factors of base course mixture with coal gangue aggregate were studied. The influence of coal gangue powder and coal gangue aggregate on performance of asphalt mortar and asphalt mixture was analyzed, and possible influencing factors and function mechanism were discussed. The results showed that heavy metal elements of coal gangue applied into asphalt pavement is not seeped out. The crushing value, water absorption and flat elongated particles content of coal gangue aggregate are generally high, but the compressive strength of base course with coal gangue aggregate is verified to meet the strength requirement. The performance, volume stability and durability of base course with coal gangue aggregate are closely related to aggregate gradation, the type and dosage of cementations materials and aggregate. The high temperature performance, temperature susceptibility and viscosity of asphalt mortar are improved by the addition of different coal gangue powder, and improvement effect of activated coal gangue powder on asphalt mortar performance is better. The low temperature performance and adhesion property of asphalt mortar with chemical activated coal gangue powder are improved. The physical reaction between asphalt and different coal gangue powder is only taken place. The temperature stability of asphalt mixture with coal gangue coarse aggregate has achieved the specification requirement. The water stability and low temperature fracture performance of asphalt mixture with fine aggregate replaced by coal gangue are improved. However, the high temperature performance of above mixture is lower than conventional hot mix asphalt mixture. The research results will provide reference for coal gangue applied into asphalt pavement.

In Vitro and In Silico Characterization of N-Formylated Two-Peptide Bacteriocin from Enterococcus faecalis CAUM157 with Anti-Listeria Activity.

Enterococcus faecalis CAUM157 (KACC 81148BP), a Gram-positive bacteria isolated from raw cow's milk, was studied for its bacteriocin production. The antimicrobial activity of CAUM157 was attributed to a two-peptide class IIb bacteriocin with potent activity against food-borne pathogen Listeria monocytogenes and periodontal disease-causing pathogens (Prevotella intermedia KCTC 15693T and Fusobacterium nucleatum KCTC 2488T). M157 bacteriocins exhibit high temperature and pH stability and resist hydrolytic enzyme degradation and detergent denaturation, potentially due to their structural conformation. Based on amino acid sequence, M157A and M157B were predicted to be 5.176kDa and 5.182kDa in size, respectively. However, purified bacteriocins and chemically synthesized N-formylated M157 peptides both showed 5.204kDa (M157A) and 5.209kDa (M157B) molecular mass, confirming the formylation of the N-terminal methionine of both peptides produced by strain CAUM157. Furthermore, the strain demonstrated favorable growth and fermentation with minimal bacteriocin production when cultured in whey-based media, whereas a 1.0% tryptone or soytone supplementation resulted in higher bacteriocin production. Although Ent. faecalis CAUM157 innately harbors genes for virulence factors and antimicrobial resistance (e.g., tetracycline and erythromycin), its bacteriocin production is valuable in circumventing the need for live microorganisms, particularly in food applications for pathogen control.

Magnetic domain structures in ultrathin Bi2Te3/CrTe2 heterostructures

Abstract Chromium tellurium compounds are important two-dimensional van der Waals ferromagnetic materials with high Curie temperature and chemical stability in air, which is promising for applications in spintronic devices. Here, high-quality spin-orbital-torque (SOT) device, Bi2Te3/CrTe2 heterostructure was epitaxially grown on Al2O3 (0001) substrates. Anomalous Hall measurements indicate the existence of strong ferromagnetism in this device with the CrTe2 thickness down to 10 nm. In order to investigate its micromagnetic structure, cryogenic magnetic force microscope (MFM) was utilized to measure the magnetic domain evolutions at various temperatures and magnetic fields. The virgin domain state of the device shows a worm-like magnetic domain structure with the size around 0.6 ~ 0.8 µm. Larger irregular-shape magnetic domains (＞1µm) can be induced and pinned, after the field is increased to coercive field and ramped back to low fields. The temperature-dependent MFM signals exhibit a nice mean-field-like ferromagnetic transition with Curie temperature around 201.5 K, indicating a robust ferromagnetic ordering. Such device can be potentially implemented in future magnetic memory technology.

Spectral studies of thermally stable Dy3+/Sm3+ co-doped Li2Ba5W3O15 phosphors for warm white LEDs

In the current study, a series of Li2Ba5W3O15: RE3+ (RE = Dy, Sm) [LBW:Dy3+/Sm3+] phosphors were prepared using a high-temperature solid-state method. X-ray diffraction, Scanning electron microscopy with energy-dispersive x-ray analysis scans showed that the crystal form was consistent with the standard LBW and comprised small irregularly shaped particles. Diffuse reflectance spectral (DRS) data was utilized to calculate the band gaps. Fluorescence study shows that LBW material doped with Dy3+ and Sm3+ yield distinct colors at 496 nm (blue) for Dy3+ and 582 nm (green-yellow), 612 nm (yellow), and 669 nm (red) for Sm3+ when excited by near-ultraviolet (336 nm) light. The observation of energy transfer between Dy3+ and Sm3+ ions play a role in modifying the luminescence of LBW:Dy3+/Sm3+ co-doped phosphors. With a constant excitation wavelength (λ Ex), different levels of activator doping lead to a change in the emission colors from their neutral white light to a deep orange-red region for LBW:Dy3+/Sm3+ phosphors. The decay curves demonstrate a decrease in lifetime with an increase in the concentration of activator ions (Sm3+). For D3S5 phosphor, the temperature-dependent photoluminescence characteristics were analyzed under λ Ex = 336 nm excitation. The results indicate excellent luminescence thermal stability with an activation energy of 0.16 eV at λ Ex = 336 nm. With its low color-correlated temperature and good thermal stability, the prepared phosphor sample shows potential as a solid-state emitting phosphor that can be used with UV chip stimulation for warm white LED applications.

High temperature stability of regrown and alloyed Ohmic contacts to AlGaN/GaN heterostructure up to 500 °C

This Letter reports the stability of regrown and alloyed Ohmic contacts to AlGaN/GaN-on-Si high electron mobility transistors (HEMTs) for high temperature applications up to 500 °C. Transfer length method (TLM) measurements from 25 to 500 °C in air show that the regrown contacts appear to be stable up to 500 °C during short term (approximately 1 h) testing, while alloyed contacts appear to decrease in contact resistance from 300 to 500 °C though increases in the error bounds due to increase sheet resistance make it difficult to conclude definitely. Additionally, longer term testing shows both technologies remain stable at least up to 48 h at 500 °C, after which the large increase in sheet resistance makes the measurement uncertainty too large to conclude definitively. Advanced microscopy images indicate both the regrown and alloyed contact regions remain structurally intact after prolonged high temperature exposure with no visible degradation in crystallinity or metal composition.

СИГНАЛЬНА МАКРОМОДЕЛЬ ОПТОПАРИ НА СТРУКТУРАХ ОРГАНІЧНОЇ ЕЛЕКТРОНІКИ

The paper is devoted to the basic approaches to the realization of the macromodel of optocouplers on organic structures for sensor devices. It is shown that the use of such structures is largely limited due to the time drift of parameters and temperature instability. In the course of the research, the possibility of compensating for these parameters directly during the operation of organic optocouples by measuring and analyzing the parameter drift was established. For this purpose, specialized built-in in-situ diagnostic systems and controlled signal transducers are used. In order to verify the functioning and optimize the parameters of signal transducers of built-in in- situ diagnostic systems, the paper describes the main approaches and the result of the implementation of the optocouple macromodel. The macromodel provides the ability to specify the components of sensor electronics optocouplers in accordance with the approaches and syntax of SPICE modeling and reflects parametric modulation with changes in ambient temperature, time instability, and flicker noise. The macromodel consists of five modules that describe the processes and specify the characteristics of the optocoupler: the light emitter (LED), self-heating of the optocoupler structure by the supply current, the optical medium or active layer of the optosensor, time drift and flicker noise, and the light receiver (photodiode or photoresistor). The modules are represented by substitution schemes of electrical components in accordance with the principle of functional analogy. The main approaches to specifying the parameters of macromodel components and examples of parametric studies based on it are considered. The use of the developed model makes it possible to obtain the values of compensation parameters for operational adjustment, in accordance with the operating conditions and properties of organic structures.

Composite polymer electrolyte facilitated by enhanced amorphousity and Li+ conduction using LaFeO3-embedded PVDF-HFP for solid-state lithium metal battery

Composite polymer electrolytes (CPEs) are a promising alternative to flammable conventional liquid electrolytes for high-safety lithium-ion batteries. Establishing low-cost filler that enhances the amorphous nature of polymer in the CPEs and exhibits efficient Lewis acid-base interaction between fillers and anions of lithium salt, leading to improved dissociation of salts for enhanced conduction, is indispensable. In this work, for the first time, we construct a solid composite polymer electrolyte of poly(vinylidene fluoride hexafluoropropylene) embedded LaFeO3 (LFO) particles prepared by solution casting and electrospinning methods and study their performances. The 5 wt% LFO filler embedded CPE made by means of solution casting and electrospinning methods exhibited the highest ionic conductivity of 5.9 × 10-4 and 1.49 × 10-3 S cm−1 at room temperature and electrochemical stability window up to 4.6 and 4.45 V, respectively. Further, as-assembled solid-state lithium-ion batteries using electrospun CPE showed an initial discharge capacity of 166 mAh/g at 0.1C-rate and solution-casted CPE showed excellent cycling stability with 98.6 % capacity retention at 0.3C-rate even at 50th cycle. Such excellent performance originated from the introduction of the LFO particles as filler into the polymer matrix to enhance the ionic conductivity, mechanical strength and lithium metal compatibility of the resulting CPEs.

IMAC application of extracellular polymeric substances doped composite membranes for α-amylase immobilization and kinetic studies

Immobilized metal affinity chromatography (IMAC), extensively utilized technique in affinity chromatography, has proven to be highly effective in purifying α-amylase, a crucial enzyme in industrial applications. Here, Poly (2-hydroxyethyl methacrylate) (PHEMA) based composite membranes were fabricated using the radical copolymerization technique in a petri dish. Extracellular polymeric materials (EPS) as the metal binding agent. The attachment of Cu2+ ions to the membranes occurred through the utilization of EPSs (Cu2+-EPS). The membranes having Cu2+-EPS (Cu2+-EPS-PM) were subjected to various characterization techniques, including scanning electron microscopy (SEM), attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR), swelling tests, and surface area measurements. The investigation also encompassed the examination of various factors, including pH, initial α-amylase concentration, temperature, and ionic strength, that exert an influence on the adsorption of α-amylase from an aqueous medium. The Cu2+-EPS-PMs demonstrated maximum adsorption capacity with a value of 54.2 mg/g polymer (pH 5.0 sodium acetate buffer, temperature: 25°C, initial α-amylase concentration of 2 mg/mL). Additionally, it has been observed that the enzyme is able to be used in adsorption and desorption cycles on Cu2+-EPS-PM many times. The investigation also focused on examining the impact of pH, temperature, storage, and operational stability over the activities of both free and immobilized α-amylase. The outcomes showed that immobilization had positive effects on activity.

Exploring the Seasonal Comparison of Land Surface Temperature Dominant Factors in the Tibetan Plateau

Abstract. LST (Land Surface Temperature) is a significant parameter that represents the ground energy balance and plays a crucial role in understanding climate change. The LST of the Tibetan Plateau (TP) has a direct influence on the climate and environmental changes of the TP, and it also has a significant impact on global climate and atmospheric circulation. Although there are various factors that drive the spatial and temporal distribution of LST on the TP, the primary driving forces and its seasonal variations of LST are not yet well understood. The research focuses specifically on the TP region, selecting three types of LST data, using geodetector model, to analyze the driving factors affecting the spatial pattern of LST in different seasons. The results indicate that the three factors, Air Temperature (AT), Elevation (Ele), and Permafrost Thermal Stability (PTS), have a significant influence on LST throughout all seasons, whereas other variables demonstrate varying contributions to LST depending on the season. This study contributes to the understanding of the spatial variability of surface thermal conditions and the intricate relationships between their driving factors. It also emphasizes the potential changes in these relationships throughout the year.

Thermophysical characterization and reliability analysis of binary composite nano doping on stearic acid-acetamide eutectic PCM

Organic phase change materials (PCM) have been extensively studied and employed for thermal energy storage applications, especially in the last decade. Wide range of melting temperature with high latent heat of fusion and absence of super cooling have made them highly desirable for energy storage applications, yet their intrinsic low thermal conductivity has been a major drawback in practical implementation. This study intends to address this and study the thermophysical characteristics of an organic PCM through composite nano doping. Stearic acid-acetamide eutectic PCM with a melting temperature of 65.73 °C and a latent heat of 203.72 J/g, was incorporated with a binary blend of Aluminum Oxide nanoparticles and multi-walled carbon nanotubes (MWCNT). The addition of metallic oxide and carbonaceous nanoparticles increased the melting temperature of the eutectic mixture by 2.9 °C and a highly advantageous increment in latent heat of fusion by 10% was observed, due to the improved molecular interaction introduced by the nanoparticles. Composite nano doping enhanced the thermal conductivity of the eutectic PCM by a 132.7% and also resulted in high optical absorption properties. The prepared eutectic mixtures were chemically stable and the eutectic PCM showed an improved final degradation temperature and thermal stability, with composite nano doping. Thermal reliability was analyzed through accelerated thermal cycling test and the eutectic mixtures could retain their thermal characteristics and chemical stability even after 500 thermal cycles. Composite nano doping proved to be a reliable thermophysical characteristics enhancement technique for organic eutectic PCM.

High Energy Storage Performance in BiFeO3-Based Lead-Free High-Entropy Ferroelectrics.

Dielectric capacitors are widely used in advanced electrical and electronic systems due to the rapid charge/discharge rates and high power density. High comprehensive energy storage properties are the ultimate ambition in the field of application achievements. Here, the high-entropy strategy is proposed to design and fabricate single-phase homogeneous (Bi0.5Ba0.1Sr0.1Ca0.2Na0.1)(Fe0.5Ti0.3Zr0.1Nb0.1)O3 ceramic, the hierarchical heterostructure including rhombohedral-tetragonal multiphase nanoclusters and locally disordered oxygen octahedral tilt can lead to the increased dielectric relaxation, diffused phase transition, diverse local polarization configurations, grain refinement, ultrasmall polar nanoregions, large random field, delayed polarization saturation and improved breakdown field. Accordingly, a giant Wrec ≈13.3 J cm-3 and a high η ≈78% at 66.4kV mm-1 can be simultaneously achieved in the lead-free high-entropy BiFeO3-based ceramic, showing an obvious advantage in overall energy-storage properties over BiFeO3-based lead-free ceramics. Moreover, an ultrafast discharge rate (t0.9 = 18ns) can be achieved at room temperature, concomitant with favorable temperature stability in the range of 20-160 °C, due to the enhanced diffuse phase transition and fast polarization response. This work provides a feasible pathway to design and generate dielectric materials exhibiting high comprehensive energy-storage performance.

Turning Ultra-Low Coercivity and Ultra-High Temperature Stability Within 897 K via Continuous Crystal Ordering Fluctuations.

High-performance soft magnetic materials are important for energy conservation and emission reduction. One challenge is achieving a combination of reliable temperature stability, high resistivity, high Curie temperature, and high saturation magnetization in a single material, which often comes at the expense of intrinsic coercivity-a typical trade-off in the family of soft magnetic materials with homogeneous microstructures. Herein, a nanostructured FeCoNiSiAl complex concentrated alloy is developed through a hierarchical structure strategy. This alloy exhibits superior soft magnetic properties up to 897K, maintaining an ultra-low intrinsic coercivity (13.6 A m-1 at 297 K) over a wide temperature range, a high resistivity (138.08µΩcm-1 at 297K) and the saturation magnetization with only a 16.7% attenuation at 897 K. These unusual property combinations are attributed to the dual-magnetic-state nature with exchange softening due to continuous crystal ordering fluctuations at the atomic scale. By deliberately controlling the microstructure, the comprehensive performance of the alloy can be tuned and controlled. The research provides valuable guidance for the development of soft magnetic materials for high-temperature applications and expands the potential applications of related functional materials in the field of sustainable energy.