Excellent Temperature Research Articles

H2O2 self-supplying Ce6@ZIF-8/PDA/CuO2/HA (CZPCH) nanoplatform for enhanced reactive oxygen species (ROS)-mediated tumor therapy

Tumor hypoxia, limited H2O2 levels, and abundant glutathione (GSH) in the tumor microenvironment (TME) pose challenges for high-efficiency reactive oxygen species (ROS)-mediated therapies. To address these limitations, an intelligent ROS-mediated nanoplatform, Ce6@ZIF-8/PDA/CuO2/HA (CZPCH), with photodynamic activity, self-supplied H2O2, Fenton-like reaction, GSH-depletion and photothermal activity was designed for efficient tumor treatment. In the acidic TME, CuO2 in CZPCH deposits into Cu2+ and H2O2, consuming GSH and triggering Fenton-like reactions to generate hydroxyl radical (•OH), enabling efficient chemodynamic therapy (CDT). Moreover, the presence of Ce6 and PDA enables CZPCH to exhibit excellent singlet oxygen (1O2) and temperature increase performance 660 nm and 808 nm laser irradiation, respectively, resulting in efficient photodynamic therapy (PDT) and photothermal therapy (PTT) efficacy. Interestingly, the temperature increase from PTT significantly enhances •OH and 1O2 generation, achieving high-efficiency ROS-based therapeutic efficacy. This synergistic CDT/PDT/PTT treatment demonstrates excellent anti-tumor efficacy and illuminates novel ROS-based therapeutic strategy design.

Preparation and thermal/dielectric properties of medium/high entropy perovskite titanate ceramics

High-entropy ceramics have garnered significant attention in recent years owing to their exceptional properties and structural diversity. In this work, single-phase medium/high entropy ceramics, namely (Ca0.2Sr0.4Ba0.4)(Zr0.5Ti0.5)O3 and (Ca0.2Sr0.4Ba0.4)(Zr0.1Ti0.9)O3, were successfully designed and prepared utilizing Spark Plasma Sintering (SPS). A comprehensive investigation was conducted into the phase structure, microscopic morphology, dielectric properties, and thermal behavior of these ceramics. It was observed that all ceramics maintained a cubic perovskite structure (space group: Pm3‾m), and the introduction of multi-element doping rendered them more stable across a wide frequency and temperature range. Notably, (Ca0.2Sr0.4Ba0.4)(Zr0.5Ti0.5)O3 exhibited remarkably low dielectric loss (0.0001 at 1 kHz) at room temperature, along with excellent dielectric temperature stability (25–400 °C). By reducing the zirconium concentration in (Ca0.2Sr0.4Ba0.4)(Zr0.1Ti0.9)O3, a slight decrease in dielectric temperature stability was observed (25–350 °C); however, it demonstrated lower thermal conductivity (0.41 W/(m·K), 1200 °C) and maintained good high-temperature stability. The discovery highlights the promising practicality of both ceramics for high-temperature dielectric applications.

Preparation and Properties of Temperature Resistant and Salt Resistant Lotion Fracturing Fluid Thickener

In order to prepare fracturing fluid with excellent solubility, temperature resistance, salt resistance and shear resistance, acrylamide (AM), 2-acrylamide-2-methylpropanesulfonic acid (AMPS) and acryloylmorpholine (ACMO) were copolymerized, and anionic cellulose was introduced to synthesize a new type of polyacrylamide copolymer p (AM/AMPS/ACMO) through inverse emulsion polymerization. The structure and morphology were characterized by infrared spectroscopy and scanning electron microscope. The results showed that in 0, 5, 10, 20, 50, 100, 150 and 200 g/L NaCl, CaCl2, and MgCl2 solutions, the viscosity of p (AM/AMPS/ACMO) solution modified by PVA fiber was always higher than that of conventional PAM solution, and the polymer modified by PVA fiber had better salt resistance. The anionic cellulose modified thickener was sheared at 120 ℃ and 150 ℃ for 1 h at 170 s－1, and the viscosity after shearing is 89.92 mPa·s and 80.10 mPa·s, respectively, which is much higher than the viscosity required by the general technical conditions of fracturing fluid more than 50 mPa·s, indicating that anionic cellulose modified p (AM/AMPS/ACMO) has good temperature and shear resistance.

Mechanical, materials, and physicochemical effects on the high-temperature tribological behaviour of laser additive manufacturing AlCoCrFeNi2.1 eutectic high-entropy alloys

ABSTRACT The AlCoCrFeNi2.1 eutectic high-entropy alloys (EHEAs) were prepared using selective laser melting (SLM) to study the tribological properties at high temperatures, focusing on the complex mechanism of the friction process. The density of the SLM EHEAs is 99.70%. The lamellar and cellular structures are unevenly distributed at different locations. In situ XRD demonstrated the transition from BCC to FCC with increasing temperature. A large number of B2 particles are distributed in the BCC matrix. The fluctuation of the friction coefficient is closely related to the shape and size of the wear debris. The hardness of the alloy is ∼105 HV at 1000 °C. The wear rate first increases and then decreases with increasing temperature. The maximum thickness of the oxide film is 13.52 μm at 1000 °C and exhibits delamination. The combination of mechanical, materials and physicochemical effects during friction contributes to the excellent high temperature wear resistance.

Enhanced energy storage performance in Pb-free Na0.5Bi0.5TiO3–Sr0.7Bi0.2TiO3-based relaxor ferroelectric ceramics through a stepwise optimization strategy

This study employed a stepwise optimization strategy, including doping Sr(Ga0.5Nb0.5)O3 (SGN) into 0.65Na0.5Bi0.5TiO3-0.35Sr0.7Bi0.2TiO3 (NBT-SBT) ceramics to modify the composition and a further processing improvement. By introducing Ga3+ and Nb5+ ions with high ionic polarization rates into the B-site, the average polarization of the unit cell was maintained while further inducing local disordered fields and promoting polar nanoregions. The high activity of the polar nanoregions was confirmed using piezoelectric microscopy. The effective energy storage density (Wrec) of 2.73 J/cm³ was obtained when the SGN doping was 6.5 %. Subsequently, the densification of ceramics was improved through viscous polymer processing, thereby enhancing the breakdown strength (BDS). A combined approach of finite element simulation and experimental studies was further utilized to investigate the impact of grain size on the BDS. The stepwise optimization strategy enabled the NBT-SBT-6.5SGNVPP ceramics to achieve the Wrec of 5.2 J/cm3 and efficiency (η) of 85 % under 350 kV/cm. Additionally, the ceramics developed by this strategy possess excellent temperature and frequency stability and pulse discharge performance, making them potential candidates for practical applications.

Substitution of Sn in the high-permeability MnZn ferrite for wide temperature applications

To meet the challenge of varied working temperatures of inductance components in new energy vehicle and 5G communication, the high-TC high-permeability MnZn ferrite with excellent temperature stability was developed by the addition of SnO2. In this series of samples, initial permeability μi maintains large values in a wide temperature range. With increasing the SnO2 content, the temperature of the second permeability peak Tsp decreases and meanwhile Curie temperature TC maintains as high as 160 °C. For the best sample with 6000 ppm SnO2, μi at 25 °C is 7244 and exhibits the excellent temperature stability with the low specific temperature coefficient of 0.35 × 10−6 °C−1 between 25 and 130 °C. The addition of SnO2 generates Fe2+ and adjusts the magneto-crystalline anisotropy constant K1 = 0 point, which is responsible for the wide-temperature high permeability. The effect of SnO2 addition on magnetization process has also been clarified.

Characterization of microstructure and mechanical properties of Ta-10W alloy manufactured by laser powder bed fusion

Ta-10W alloy is an important high temperature structure material because of its high melting point and excellent high temperature performance. Laser powder bed fusion (LPBF) provide a new scheme to break limitation in producing Ta-10W complex structures. High-density Ta-10W samples manufactured by LPBF were first achieved in this work. The variation of molten pool morphology and interior defects with energy density was investigated, and excellent mechanical properties in room temperature were obtained.

Excellent Persistent Near-Infrared Room Temperature Phosphorescence from Highly Efficient Host-Guest Systems.

Organic near-infrared (NIR) room temperature phosphorescence (RTP) materials become a hot topic in bioimaging and biosensing for the large penetration depth and high signal-to-background ratio (SBR). However, it is challenging to achieve persistent NIR phosphorescence for severe nonradiative transitions by energy-gap law. Herein, a universal system with persistent NIR RTP is built by visible (host) and NIR phosphorescence (guest) materials, which can efficiently suppress the nonradiative transitions by rigid environment of crystalline host materials with good matching, and further promote phosphorescence emission by the additional phosphorescence resonance energy transfer (≈100%) between them. The persistent NIR phosphorescence with ten-folds enhancement of RTP lifetimes, compared to those of guest luminogens, can be achieved by modulation of aggregated structures of host-guest systems. This work provides a convenient way to largely prolong the phosphorescence lifetimes of various NIR luminogens, promoting their application in afterglow imaging with deeper penetration and higher SBRs.

Supramolecularly Connected Armor-like Nanostructure Enables Mechanically Robust Radiative Cooling Materials.

Passive daytime radiative cooling (PDRC) is a promising practice to realize sustainable thermal management with no energy and resources consumption. However, there remains a challenge of simultaneously integrating desired solar reflectivity, environmental durability, and mechanical robustness for polymeric composites with nanophotonic structures. Herein, inspired by a classical armor shell of a pangolin, we adopt a generic design strategy that harnesses supramolecular bonds between the TiO2-decorated mica microplates and cellulose nanofibers to collectively produce strong interfacial interactions for fabricating interlayer nanostructured PDRC materials. Owing to the strong light scattering excited by hierarchical nanophotonic structures, the bioinspired film demonstrates a desired reflectivity (92%) and emissivity (91%) and an excellent temperature drop of 10 °C under direct sunlight. Notably, the film guarantees high strength (41.7 MPa), toughness (10.4 MJ m-3), and excellent environmental durability. This strategy provides possibilities in designing polymeric PDRC materials, further establishing a blueprint for other functional applications like soft robots, wearable devices, etc.

Interfacial compatible PolyMOF membranes as ratiometric fluorescence temperature sensors

Cryogenic temperature sensors play significant roles in manufacturing, metallurgy, and aerospace. Metal-organic frameworks (MOFs) as emerging crystal materials exhibited inherent advantages as fluorescence temperature sensors and researchers have shifted their focus toward incorporating MOFs materials into mixed matrix membranes (MMMs) for broader practical applications. However, the poor interfacial compatibility between MOFs particles and the polymer matrix would cause aggregation-induced fluorescence quenching and reduced energy transfer efficiency, thereby compromising temperature sensing performances. Herein, we adopt a post-synthetic copolymerization strategy to realize an interfacial-compatible membranous ratiometric luminescent thermometer based on the emissions of ligands and lanthanide ions. Benefiting from the controllable covalent cross-linking structures, the designed polyMOF membrane exhibited excellent interfacial compatibility and avoided MOFs irregular morphology agglomeration and phase separation, which contributed to outstanding fluorescence temperature sensing performance with excellent sensitivity ranging from 0.300 to 0.745 %·K−1 within the temperature range of 80–300 K, superior to recent reported MOFs-based thermometers. This research presents a promising approach for the design and fabrication of interfacial compatible MOFs-based membranes with excellent fluorescence temperature sensing properties, advancing the understanding of structure-property relationships and accelerating the practical applications.

Temperature-Induced Luminescence Intensity Fluctuation of Protein-Protected Copper Nanoclusters: Role of Scaffold Conformation vs Nonradiative Transition.

Protein-scaffolded atomically precise metal nanoclusters (NCs) have emerged as a promising class of biofriendly nanoprobes at the forefront of modern research, particularly in the area of sensing. The photoluminescence (PL) intensity of several nanoclusters showed a systematic temperature-dependent fluctuation, but the mechanism remains ambiguous and is poorly understood. We tried to shed some light on this mechanistic aspect by testing a couple of hypotheses: (i) conformational fluctuation of the protein scaffold-mediated PL intensity fluctuation and (ii) PL intensity fluctuation due to the variation in the radiative and nonradiative transition rates. Herein, the PL intensity of the lysozyme-capped copper nanocluster (Lys-Cu NC) showed excellent temperature dependency; upon increasing the temperature, the PL intensity gradually decreased. However, contrasting effects can be seen when the nanocluster is exposed to a chemical denaturant (guanidine hydrochloride (GdnHCl)); the PL intensity increased with the increase in the GdnHCl concentration due to the change in the ionic strength of the medium. This discrepancy clearly suggests that the thermal PL intensity fluctuation cannot be explained by a change in the scaffold conformation. Furthermore, upon closer investigation, we observed a 2-fold increase in the nonradiative decay rate of the Lys-Cu NC at the elevated temperature, which could reasonably explain the decrease in the PL intensity of the nanocluster at the higher temperature. Additionally, from the result, it was evident that the protein scaffold-metal core interaction played a key role here in stabilizing each other; hence, the scaffold structure remained unaffected even in the presence of chemical denaturants.

Ultra-long room temperature phosphorescent materials based on tetraphenylethylene derivatives for anti-counterfeiting and encryption applications

Stimuli-responsive room temperature phosphorescent materials have been the subject of considerable research activity in recent years. In this study, the tetraphenylethylene group was selected in combination with arylboronic acid (TIPE-BOH) and used to dope a rigid polyvinyl alcohol (PVA) matrix to generate a film material (TIPE-BOH-PVA) that exhibited an aggregation-induced emission (AIE) effect. The prepared film exhibits excellent room temperature phosphorescence (RTP) performance, with an enhanced emission wavelength and an afterglow time of up to 12 s. The triplet-to-singlet Förster resonance energy transfer (TS-FRET) has been utilized to modify the afterglow color by adding butyl rhodamine B (BRhB) and rhodamine 6G (R6G), employing a water phase without the use of organic solvents. The resultant material exhibits stimulus responsiveness; the RTP properties disappear when the material is exposed to water vapor, but are restored following thermal treatment. The material has potential applications in information encryption and erasure, double anti-counterfeiting ink, and fingerprint acquisition systems. This work offers a new strategy for the design of stimuli-responsive ultra-long RTP materials with far-ranging end applications.

Ceramic-Based Dielectric Materials for Energy Storage Capacitor Applications.

Materials offering high energy density are currently desired to meet the increasing demand for energy storage applications, such as pulsed power devices, electric vehicles, high-frequency inverters, and so on. Particularly, ceramic-based dielectric materials have received significant attention for energy storage capacitor applications due to their outstanding properties of high power density, fast charge-discharge capabilities, and excellent temperature stability relative to batteries, electrochemical capacitors, and dielectric polymers. In this paper, we present fundamental concepts for energy storage in dielectrics, key parameters, and influence factors to enhance the energy storage performance, and we also summarize the recent progress of dielectrics, such as bulk ceramics (linear dielectrics, ferroelectrics, relaxor ferroelectrics, and anti-ferroelectrics), ceramic films, and multilayer ceramic capacitors. In addition, various strategies, such as chemical modification, grain refinement/microstructure, defect engineering, phase, local structure, domain evolution, layer thickness, stability, and electrical homogeneity, are focused on the structure-property relationship on the multiscale, which has been thoroughly addressed. Moreover, this review addresses the challenges and opportunities for future dielectric materials in energy storage capacitor applications. Overall, this review provides readers with a deeper understanding of the chemical composition, physical properties, and energy storage performance in this field of energy storage ceramic materials.

Sandwich-structured SrTiO3/PEI composite films with high-temperature energy storage performance

Dielectric capacitors are widely used in aerospace and power systems due to their non-polluting, high power density and fast charge/discharge rates. Polyetherimide (PEI) exhibits excellent temperature tolerance, high withstand voltage and low dielectric loss. However, its relatively low dielectric constant restricts its energy storage density. In this paper, a sandwich-structured composite film with the outer layer of pure PEI and the middle layer of strontium titanate (SrTiO3)/PEI is prepared by the solution casting method. At room temperature, the composite film with 5 vol% two-dimensional (2D) SrTiO3 plates achieves an outstanding energy storage density of 19.46 J cm−3 and an ultra-high energy storage efficiency of 97.05% under an electric field of 630 MV m−1. Furthermore, this composite film exhibits a maximum energy storage density of 10.34 J cm−3 and an energy storage efficiency of 88.13% at 150 °C. Combined with finite element simulation results, it confirms that the synergistic effect of 2D SrTiO3 plates and sandwich-structured can effectively hinder the development of electric trees. This work presents a sophisticated approach to design and preparation of dielectric composites suitable for the applications of high-temperature energy storage.

Enhanced interfacial, mechanical, and anti-hygrothermal properties of carbon fiber/cyanate ester composites with the catalytic sizing agents of titanium epoxy

The mechanical properties of composites are closely related to the interfacial behavior, especially under the hygrothermal circumstance. A catalytic sizing agent of titanium epoxy is designed to enhance interfacial, mechanical, and anti-hygrothermal properties of high modulus carbon fiber (HMCF)/cyanate ester composites simultaneously. The mechanisms of interface enhancement and low hygroscopicity of composites are investigated. The titanium epoxy is synthesized and its catalytic effect on the curing of cyanate ester is proved. The interfacial properties of HMCF composites with catalytic sizing agents are improved to 95.5 MPa, which is attributed to the interphase with high crosslinking density and sufficient triazine rings and oxazolidinone structure due to preferential curing induced by interfacial catalysis, stimulating the smooth transition of interphase modulus. Further, the formed interphase exhibits few interface defects and low content of hydroxyl groups, which changes the moisture diffusion path and reduces saturated water absorption of composites to only 0.36 %, resulting in the release of interfacial wet stress concentration and high retention of mechanical properties in hygrothermal environment. The resultant composites with high stiffness, excellent temperature resistance, superior dimensional stability and low moisture absorption are expected to be applied to high-orbit space, aerospace, precision instruments.

Numerical analysis and ANN performance prediction of solar composite ventilation wall for built environment regulation

With the aim to achieve winter heating, summer heat insulation and year-round power generation as well as indoor pollutant purification, photovoltaic (PV) combined with phase change heat storage technology is ingeniously embedded in an adjustable solar composite ventilation wall with entire room model (SPVW-PV/PCM) in this study. Then, the effects of key parameters e.g. PCM melting temperature Tm and PV coverage ratio Cr on solar energy conversion and utilization with indoor environment creation are comprehensively illustrated by indoor temperature, exergy efficiency as well as power generation amount. In addition, to further clarify the application potential of the proposed model applied in different typical places in China, the artificial neural network (ANN) has been rarely adopted to predict the annual heating amount, power generation as well as its economic and environmental benefits. Research results show that the three numerical submodels closely align with previously published results, with only minor discrepancies observed in the decoupling model regarding Cout, vroom and PCM melt fraction, well within acceptable numerical tolerances of 9.87% RMSE. The thermal performance is significantly influenced by the key parameters of Tm and Cr, with at least 110 min of advance heating start-up time revealed, and excellent indoor temperature improvement of 1.59 K and 3.02 K are achieved in the heating season at Tm = 318 K or Cr = 0 % simulated group. The highest annual total energy conversion of 1367.39 kWh is surveyed in Guangzhou, corresponding to the lowest levelized cost of electricity (LCOE) of 0.18 $/kWh and the highest CO2 saving cost of 19.03 $/year. The total energy conversion effect and the CO2 saving cost can be effectively improved by 13.88 % and 13.82 % in Guangzhou, respectively, compared to the coupling off-grid PV and conventional wall in building. These research findings offer valuable insights for optimizing the design of SPVW-PV/PVM in indoor environmental construction and enhancing its overall applicability.

Preparation and characterization of phase change material emulsions and their applications in liquid cooling systems for wind turbines

In order to improve the effect of liquid cooling system for wind turbine, this study used ultrasonic preparation method, stearic acid as phase change material, sorbitan trioleate and sodium lauryl sulfate as compound surfactants successfully prepared stearic acid phase change material emulsion as a cooling medium for investigation. The characterization, thermophysical properties, and fluidity of stearic acid phase change material emulsions at varying concentrations were examined through differential scanning calorimetry, thermal constant analysis, and viscometry. To investigate the cooling effects, a stator axial liquid cooling model was developed for both water and a 14 % stearic acid phase change material emulsion. Findings revealed that the 14 % stearic acid phase change material emulsion exhibited a latent heat of phase change of 22.5 J/g, reaching a peak melting temperature of 68.7 °C. Additionally, the latent heat of solidification was measured at 21.08 J/g, accompanied by a peak solidification temperature of 60.3 °C. The maximum thermal conductivity reached 0.5801 W/(m·K), and the specific heat capacity peaked at 5219.8 J/(K·mol), marking a notable improvement of 1.26 times. Under an inlet temperature of 30 °C and a flow rate of 1 L/min, stearic acid phase change material emulsion effectively lowered the temperatures of the windings, stator, rotor, and casing by 19.2 °C, 23.6 °C, 19.2 °C, and 9.6 °C, respectively. stearic acid phase change material emulsion demonstrates excellent temperature control effectiveness at 3600 r/min and a low flow rate of 1 L/min, showcasing efficient energy utilization efficiency.

Synthesis of InZrOx nanosheets and its application in CO2 hydrogenation to methanol

Synthesis of methanol via CO2 hydrogenation is a very important reaction. In recent years, the In2O3 based catalysts were proved to be a sort of promising catalysts to accelerate this reaction, which have aroused extensive attention. However, design of novel In2O3 based catalysts that can efficiently produce methanol from CO2 hydrogenation at low temperature is still in great need. Herein we fabricated the InZrOx nanosheets via a simple solvothermal method, which had peculiar surface structure and plenty of oxygen defects. The InZrOx nanosheets displayed excellent low temperature catalytic performance in a slurry reactor. The methanol selectivity (90 %) and activity (1.4 mmol gIn-1h−1) were achieved at 180 °C, which are 2.3 and 1.6 times than that of the counterpart nanoparticles, respectively. Water as a clean and cheap reaction solvent played a crucial role, which participated in the kinetic process of the catalysis. The particular catalyst structure and the solvent effect of water accounting for the outstanding reaction results.

On the deformation induced heterogeneous precipitation of γ″ phase in Inconel 718 alloy

The unique coherency strain hardening mechanism and sluggish precipitation kinetics of γ″ phase have enabled Inconel 718 excellent elevated temperature serving performance and formability. However, the orienting character of γ″ phase determines its precipitation mutability and its morphology is susceptible to external stress and plastic deformation. Inconel 718 alloy is generally fabricated through plastic processing technologies like forging and rolling, where heterogeneous γ″ particles are commonly observed after aging. Therefore, it is vital to reveal the structural factor inducing the heterogeneous γ″ precipitation caused by deformation to lay fundamentals for particle configuration control. For this purpose, the present work aimed to define the heterogeneous γ″ configuration induced by prior deformation and explore the relevant structural mechanism. The γ″ particle morphologies in directly-aged cold-rolled Inconel 718 were characterized, prior rolling deformation resulted in heterogeneous γ″ precipitation during the aging process, which was defined as the inequivalence in their relative number fraction and particle size of perpendicular γ″-variants. Deformation led to the formation of β grains with lattice distortion in Inconel 718 alloy, which was the primary structural factor to induce the heterogeneous γ″ precipitation. These results explained that the FCC-γ lattice distortions caused by plastic deformation were responsible for the heterogeneous precipitation of second-particles.

White carbon dots with high quantum yield and multicolor carbon dots synthesized by the microwave method in one step

In the field of optics, carbon dots (CDs) have been extensively studied and have made rapid advancements in related fields, including bioimaging, optoelectronic devices and optical probes. However, it is difficult to efficiently synthesize high quantum yield (QY) white fluorescence CDs and multicolor CDs, which restricts their development in the field of optics. In this work, we chose formamide as the reaction solvent and used citric acid (CA) and 4-bromo-1,2-diaminobenzene to synthesize high-performance white fluorescent CDs20 with a QY of up to 87.5% and excellent stability (28 days). The reaction solvents (water, N,N-dimethylformamide and ethanol) were changed to obtain colorful CDs20 (orange, green and yellow) covering a broader visible spectrum via a microwave method. The solid model, which combines white fluorescent CDs20 and polyvinyl alcohol (PVA), exhibits strong white fluorescence as well as a solution state. To develop white-emitting diodes suitable for indoor use, a white CDs20 / PVA mixture with brilliant white fluorescence might be placed on ultraviolet (UV) chips (365 nm). The white LED had a high color purity (0.34, 0.25), excellent correlation color temperature (4250 K) and color rendering index (72.5). The results above show that white CDs have great promise for use in optical device fields.