Stability Enhancement Research Articles

The KEu(WO4)2 Red Phosphor Co-doped with Li+ and SO42− for Synergistic Enhancement of High Efficiency and Thermal Stability

The KEu(WO4)2 Red Phosphor Co-doped with Li+ and SO42− for Synergistic Enhancement of High Efficiency and Thermal Stability

Enhancing the Chemical Stability of P12L24 Cage: Transformation of the Chemically Labile Imine Cage into a Robust Carbamate Cage.

Herein, we report enhancement in chemical stability of the imine-based porphyrinic cage P12L24 by converting it into a robust carbamate porphyrinic cage, c-P12L24, through a two-step post-synthetic modification process. First, the imine bonds in P12L24 were reduced to form an amine-based cage, r-P12L24, followed by carbamation using N,N'-carbonyldiimidazole (CDI) to yield c-P12L24. The resulting carbamate cage exhibits high stability under acidic and basic conditions (pH 1-13) and in the presence of moisture. 1H NMR, DOSY NMR, and DFT calculations revealed that reducing the imine bonds to amine increases the framework's flexibility, causing partial structural collapse, whereas the carbamate formation restores structural rigidity. The insertion of a 4.0 nm molecular ruler into the cavity of zinc-metallated c-P12L24 via metal-ligand coordination further confirmed restoration of the cavity size and geometry of the original cage. This enhancement of chemical stability through carbamate formation can pave the way to a wide range of potential applications for the gigantic porphyrinic cage.

Formicarium-Like Micron Porous Si Synergistically Adjusted by Surface Hard-Soft Nanoencapsulation as Long-Life Lithium-Ion Battery Anode.

Micron porous silicon (MPSi) is a promising lithium-ion battery (LIB) anode that can provide enough space to effectively alleviate the volume expansion and large number of transmission channels to rapidly transport the Li-ions. However, a long-term stable MPSi anode at high current density is still a great challenge. Herein, a double-regulated formicarium like-MPSi composite using the surface hard-soft titanium dioxide-few layered MXene nanotemplate (FMPSi@TiO2@FMXene) was designed and synthesized via an in situ assembly strategy as long-life LIB anode. Such hard-soft TiO2-FMXene nanoencapsulation can collaboratively tune the internal/external stress, inhibit the volume expansion, reduce the interfacial reactions, and improve the electrical conductivity of MPSi, resulting in the great enhancement of structural stability and electrochemical performance in cycling even at high current density. Especially, this FMPSi@TiO2@FMXene anode exhibits a high reversible capacity of 1254.9 and 970.4 mAh/g after 500 cycles at 0.5 and 1 A/g, respectively. Moreover, a full cell is assembled with the FMPSi@TiO2@FMXene anode and commercial LiFePO4 (LFP) cathode, exhibiting a high capacity retention rate of 91.6% in 100 cycles. This work provides an effective surface nanoengineering tactic to obtain the structurally stable MPSi anodes by hard-soft nanotemplate for large-scale and long-term LIB application.

Kratom Alkaloids: A Blood–Brain Barrier Specific Membrane Permeability Assay-Guided Isolation and Cyclodextrin Complexation Study

Mitragynine is an “atypic opioid” analgesic with an alternative mechanism of action and a favorable side-effect profile. Our aim was to optimize the alkaloid extraction procedure from kratom leaves and to determine and isolate the most relevant compounds capable of penetrating the central nervous system. The PAMPA-BBB study revealed that mitragynine and its coalkaloids, speciociliatine, speciogynine, and paynantheine, possess excellent in vitro BBB permeability. An optimized sequence of CPC, flash chromatography, and preparative HPLC methods was used to isolate the four identified BBB+ alkaloids. To improve the bioavailability of the isolated alkaloids, their cyclodextrin (CD) complexation behavior was investigated via affinity capillary electrophoresis using almost 40 CD derivatives. The apparent alkaloid–CD complex stability constants were determined and compared, and the most relevant CDs phase-solubility studies were also performed. Both the neutral and negatively charged derivatives were able to form complexes with all four kratom alkaloids. It was found that cavity size, substituent type, and degree of substitution also influenced complex formation. The negatively charged Sugammadex, Subetadex, and the sufoalkylated-beta-CD analogs were able to form the most stable complexes, exceeding 1000 M−1. These results serve as a good basis for further solubility and stability enhancement studies of kratom alkaloids.

Research on static voltage stability enhancement for new energy station based on grid-forming control strategy

The advent of novel power systems has given rise to a multitude of safety and stability concerns associated with the integration of emerging energy sources and power electronic equipment. The active support of the grid-forming control strategy represents an effective solution to the voltage and frequency stability issues associated with the weak damping and low inertia inherent to high-ratio new energy systems. Firstly, a static voltage stability index based on critical impedance is proposed for assessment of the static stability margin of a new energy grid-connected system, based on the static voltage stability theory of a traditional single-unit single-load system. Secondly, an analysis is conducted of the control principle of the grid-forming control converter and its impedance characteristics. In conclusion, a method for enhancing the static voltage stability margin of grid-connected new energy stations through parameter control of grid-forming converters is presented. The simulation verification of the single-feed and multi-feed systems demonstrates the efficacy and accuracy of the methodology presented in this study.

Enhancement of colour density and anthocyanin stability in pomegranate juice against 5-hydroxymethylfurfural at different concentrations by amino acid copigmentation during storage

This study investigated the effect of amino acid [aspartic acid (Asp), phenylalanine (Phe) and valine (Val)] copigmentation on pomegranate juice (PJ) anthocyanins in the presence of 5-hydroxymethylfurfural (HMF) at different concentrations (2.3–15.2 mg/L) during storage at 20°C. A decrease in stabilities of anthocyanin and colour density (CD) was observed at 5.2–8.2 mg HMF/L. However, 15.2 mg HMF/L prevented the decrease in anthocyanin stability. In this sample, copigmentation occurred when ratios of "cyanidin-3,5-diglucoside to HMF" and "cyanidin-3-glucoside to HMF" were 1.82–2.67 and 1.91–2.85, respectively. The highest reduction in HMF content resulted from addition of Val. As number of –CH3 groups in an amino acid increased, HMF reducing effect of amino acid increased. In PJ containing 8.2 mg HMF/L, Val provided the highest stabilities for individual anthocyanins, CD and hyperchromic effect (HE). Asp increased the stability of CD and HE in PJ containing 5.2 mg HMF/L, while Phe increased the stability of CD at a concentration of 15.2 mg HMF/L. Depending on the amount of HMF, the effect of adding amino acids to PJ to improve colour stability and reduce HMF content varies. Therefore, after determining the initial HMF content of PJ, the amino acid to be added to PJ should be decided.

Glycoside-Mediated Enhancement of Stability in Aluminum Oxyhydroxide Nanoadjuvants during Freeze-Drying.

Aluminum-based adjuvants have been indispensable to vaccine potency. However, their effectiveness is difficult to maintain after freeze-drying, which limits the storage and application of aluminum-adjuvanted vaccines. In this study, the impact of freeze-drying on aluminum oxyhydroxide nanorods (AlOOH NRs) was investigated. Freeze-drying led to aggregation and resulted in the loss of the surface hydroxyl content of aluminum adjuvants. To alleviate freeze-drying-induced damage, the potency of different alkyl glycosides as protectants was further evaluated. It was demonstrated that the structural balance of the head and tail of a glycoside was more conducive to protecting AlOOH NRs from aggregation and loss of surface hydroxyl groups. These results underline the proper selection of protectants to protect adjuvants against functional defects caused by freeze-drying, which is important for the stability and efficacy of vaccines and biopharmaceutical products.

Kinetics Enhancement of High‐Voltage LCO via In‐Situ Formed Cyanide‐Rich Polymer Interfaces

AbstractLithium cobalt oxide (LiCoO2) is widely used as cathode material for lithium‐ion batteries due to its high operation voltage and high specific capacity. However, conventional LiCoO2 (LCO) undergoes severe structural phase transitions and compositional changes at high voltage (>4.4 V) leading to failure. Herein, a multifunctional crosslinked polymer interface is insitu formed on LCO particles, which can build a nanoscale conformal coating layer on the interface of LCO, preventing the side reaction with the electrolyte. Moreover, thanks to its high‐voltage talerances and high Li+ conductivity, the in‐situ polymerized interface has excellent high‐voltage stability and Li+ transport kinetics, which significantly improves the electrochemical performances of LCO at 4.55 or 4.6 V. This study confirms the feasibility of in situ polymer modification of LCO, providing new ideas and methods for the structural stabilization and performance enhancement of high‐voltage lithium cobalt oxides.

Facile Synthesis and Thermal Stability Enhancement of Sulfurized Polyacrylonitrile for Thermal Battery Cathodes

Although sulfide-polyacrylonitrile (SPAN) is considered a promising cathode material for various battery applications, their application in thermal batteries has not yet been explored. Herein we synthesized carbonized SPAN (c-SPAN) to enhance the thermal stability of SPAN and evaluated its application as a cathode for thermal batteries. The efficiency of c-SPAN materials was demonstrated by comprehensive structural analysis and thermal stability evaluation, including scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman, and thermogravimetric analysis (TGA). The c-SPAN exhibited significantly improved thermal stability compared to conventional PAN, which was attributed to the stable structure resulting from the chemical bonding of sulfur to the PAN-derived turbostratic carbon matrix. In addition, the bond dissociation energy of the C–S bond (272 kJ/mol) was higher than that of the S–S bond (251 kJ/mol), further contributing to the enhanced thermal stability. The thermal stability of c-SPAN was considerably affected by the mixing method and thermal treatments conditions, and maintained stability up to 500°C under optimal conditions. Additionally, a thermal battery incorporating c-SPAN was successfully operated, indicating that the c-SPAN material developed in this study is a viable candidate for thermal battery applications. These results suggest it is one of the promising cathode materials for various thermal battery applications.

Current Advancements in the Behavior Analysis of EPDM Elastomers in Peripheral Applications of the Cathodic Side of PEMFC Systems

This review examines the latest developments in the study of how Ethylene Propylene Diene Monomer (EPDM) elastomers behave in peripheral applications of Proton Exchange Membrane Fuel Cells (PEMFCs), specifically on the cathodic side. The review highlights the crucial role of EPDM in maintaining the integrity and efficiency of PEMFCs in challenging conditions characterized by varying temperatures, humidity, and acidic environments. The study examines the impact of various additives and vulcanization procedures on EPDM's mechanical and chemical properties, demonstrating enhancements in tensile strength, thermal stability, and chemical resistance. The study also investigates the compounding methods and selection of fillers, such as silica and carbon black, to optimize the performance of EPDM. Additionally, the effects of prolonged operational circumstances on EPDM's mechanical integrity and aging resistance in PEMFCs are being examined. This research emphasizes EPDM's suitability for long-term use in fuel cell systems. This review aims to guide the design of more durable and efficient PEMFC systems by optimizing the use of EPDM elastomers.

Plating after tumor curettage in human femora does not efficiently improve torsional stability ex vivo

BackgroundSurgical treatments of benign primary bone tumors of the femur face the challenge of limiting tissue damage and contamination while providing sufficient stabilization to avoid fracture. While no clear treatment guidelines exist, surgical treatment commonly consists of femoral fenestration and curettage with optional filling and plating of the defect. Mono- or bicortical plating of distal femoral defects aim to reduce fracture risk and have been shown to increase axial stability. However, it remains unclear whether plating increases torsional stability of the affected femur. Questions/purposesThis biomechanical study aimed to determine how much additional stability can be achieved by mono- or bicortical plating of femoral defects after fenestration. The following hypotheses were investigated: 1. Preventive plating of distal femur bone defects enhances torsional stability when compared to femoral fenestration alone. 2. A condition close to the intact (nonpathological) bone can be achieved by bone plating. 3. Defect shape influences torsional stability. Patients and methodsThiel embalmed human femora (n = 24) were left intact or subjected to the following surgical treatments (A) defect creation via fenestration, (B) defect with short monocortical plating, (C) defect with long bicortical plating. All femora were torsion tested in midstance position using pre-cycling and testing until failure. Quantitative computed tomography pre and post testing allowed bone mineral density calculation and crack path analysis. Finite element analysis provided insight into defect shape variations. ResultsTorsion experiments showed no relevant enhancement of torsional stability due to mono- or bicortical plating. There were no significant differences in maximum torque between unplated and plated femora with defect (defect: 35.38 ± 7.53 Nm, monocortical plating: 37.77 ± 9.82 Nm, bicortical plating: 50.27 ± 9.72 Nm, p > 0.05). Maximum torque for all treatment groups was significantly lower compared to intact femora (155–200 Nm, p < 0.001). Cracks originated predominantly from the proximal posterior corner of the defect and intersected with screw holes in plated femora. The influence of variations of the defect corner shapes had no significant influence on maximum torque and angle. ConclusionThis biomechanical study shows that mono- or bicortical plating is not an effective preventive treatment against torsional failure of femora with distal defects as the resulting maximum torque was drastically reduced compared to intact femora. Thus, the initial hypotheses have to be rejected. As habitual loading of the femur includes a combination of axial and torsional loading, the observed lack of prevention against torsional failure might help to explain the occurrence of fractures despite plating. Future research towards ameliorating clinical outcome should address the role of defect filling with bone cement or bone grafts regarding the improvement of torsional stability after primary bone tumor treatment in the femur.

Enhancement of Stability and Conductivity of α-Fe2O3 Anodes by Doping with Cs+ for Lithium-Ion Battery

Enhancement of Stability and Conductivity of α-Fe₂O₃ Anodes by Doping with Cs⁺ for Lithium-Ion Battery

A novel highly efficient co-catalyst for enhancement of photocatalytic hydrogen production activity and stability of Cd0.5Zn0.5S: Silicotungstic acid nanoparticles embedded with NiOx clusters

A novel highly efficient co-catalyst for enhancement of photocatalytic hydrogen production activity and stability of Cd0.5Zn0.5S: Silicotungstic acid nanoparticles embedded with NiOx clusters

A multi-task learning framework for aerodynamic computation of two-dimensional airfoils

Accurate and efficient prediction of airfoil aerodynamic coefficients is essential for improving aircraft performance. However, current research often encounters significant challenges in balancing accuracy with computational efficiency when predicting complex aerodynamic coefficients. In this paper, a Multi-Task Learning framework for Aerodynamic parameters Computation (MTL4AC) of two-dimensional (2D) airfoils is proposed. The MTL4AC processes two key subtasks: flow field prediction and pressure coefficient prediction. These two subtasks complement each other to reveal both global and local aerodynamic changes around the airfoil. The flow field prediction provides a coarse-grained global perspective, which focuses on the pressure and velocity variations on and around the airfoil surface. The pressure coefficient prediction offers a fine-grained local perspective, which concentrates on the pressure distribution on the airfoil surface to accurately calculate lift and drag coefficients. The MTL4AC demonstrated substantial improvements in the experiments conducted on the public dataset, achieving significant enhancements in accuracy and stability. This research contributes an accurate and efficient framework for aerodynamic computation, integrating geometric features and advanced multi-task learning techniques to achieve superior performance in predicting aerodynamic coefficients.

Intelligent Adjustment Ventilation Duct Design and Numerical Simulation Study on Enhancement of Subgrade Thermal Stability in Cold Regions

Intelligent Adjustment Ventilation Duct Design and Numerical Simulation Study on Enhancement of Subgrade Thermal Stability in Cold Regions

Multifunctional lanthanum oxide-doped carboxymethyl cellulose nanocomposites: A promising approach for antimicrobial and targeted anticancer applications

This study presents the synthesis and characterization of lanthanum oxide (La₂O₃)-doped carboxymethyl cellulose (CMC) nanocomposites via a solution casting method, designed to offer an eco-friendly, multifunctional material with significant potential in biomedical applications. Structural analysis using FTIR, XRD, and EDX confirmed successful La₂O₃ integration, with FTIR spectra indicating a distinctive LaO stretching peak at 628.2 cm−1, XRD patterns revealing enhanced crystallinity with notable peaks at 16.6°, 27.6°, and 49.8°, and EDX showing a uniform lanthanum distribution with a 10.41 mass% concentration. These enhancements in structural stability and crystalline properties underscore the composite's functional robustness. Biological assessments revealed the composite's substantial antimicrobial efficacy, demonstrating inhibition zones up to 31 mm against pathogenic strains such as E. coli, S. aureus, E. faecalis, K. pneumoniae, and C. albicans at a 15 wt% La₂O₃ concentration—surpassing conventional antimicrobial agents. Minimum inhibitory concentration (MIC) tests supported these findings, showing MIC values as low as 7.82 μg/mL, further validating the composite's heightened antimicrobial potency compared to pure CMC. In vitro cytotoxicity assays indicated selective anticancer effects of the La₂O₃/CMC nanocomposites, with IC₅₀ values of 327.7 μg/mL and 189.8 μg/mL against PC-3 prostate and A549 lung cancer cells, respectively. Remarkably, the composite showed minimal impact on normal lung fibroblasts (Wi-38), with an IC₅₀ value of 956.8 μg/mL, emphasizing its selectivity towards cancer cells. Collectively, these results highlight the La₂O₃/CMC composite as a biocompatible and multifunctional material suitable for both antimicrobial and targeted anticancer applications, aligning with the growing demand for safe, effective biomedical solutions.

Enhancement of luminescence and thermal stability in Eu3+-doped K3Y(BO2)6 with Li+ and Na+ co-doping

Eu3+-doped and Li+/Na+ co-doped K3Y(BO2)6 (KYBO) phosphors were synthesized through a microwave-assisted sol–gel method, and their structural and photoluminescent (PL) characteristics were examined. X-ray diffraction (XRD) and Rietveld refinement confirm effective dopant incorporation and preservation of the crystalline structure. Fourier Transform Infrared (FTIR) spectroscopy indicates the maintenance of the borate structure, confirming the structural integrity of the phosphors upon doping. The addition of Li+ and Na+ co-dopants notably enhances luminescent efficiency and thermal stability, making these phosphors promising candidates for solid-state lighting (SSL) applications. PL analysis reveals strong red emission peaks at 612 nm, attributed to the 5Do → 7F2 transition of Eu3+ ions. The study indicates that electric dipole-quadrupole interactions are the primary mechanism for energy migration, with a critical distance of approximately 22.68 Å. This mechanism contributes to concentration quenching at higher doping levels. High temperature PL measurements indicated an activation energy of 0.1389 eV for thermal quenching in the Li+ co-doped sample. Additionally, the Na+ co-doped sample exhibited an abnormal thermal stability behavior, with an even higher activation energy of 0.2536 eV. This suggests that Na+ co-doping significantly enhances the thermal resilience of the phosphor, making it more suitable for high-power light-emitting applications that operate under extreme conditions. CIE chromaticity diagrams highlight the potential for optimizing Eu3+ doping levels, combined with Li+ and Na+ co-doping, to improve luminescent performance and thermal stability for advanced SSL applications.

Enhanced Sodium Storage in MXene Transition Metal Chalcogenides Anode through Dual Molten Salt Etching

Referred to as potential options for anodes in sodium-ion batteries, transition metal chalcogenides (TMCs) exhibit unique electronic and structural characteristics. However, the limited electrical conductivity inherent in them poses a hindrance to electron transport, while their tendency to undergo volumetric expansion during cycling exacerbates structural instability, thereby imposing constraints on practical applications. Herein, a dual molten salt etching strategy followed by a sulfidation-selenidation process was employed to anchor multi-component sulfides FeS2/NiS and FeSe/NiSe onto conductive Ti3C2Tx MXene, achieving superior sodium storage performance. Owing to the enhanced Na⁺ and faster kinetics of electronic transport, mechanical strain is effectively reduced, and strong covalent interactions are formed at the interface, significant enhancement in the cycling stability is observed for the anodes of Ti3C2Tx@FeS2/NiS and Ti3C2Tx@FeSe/NiSe (with specific capacities of 309.4 and 162.6 mAh g−1, respectively, after 1000 cycles at 5 A g−1, with a former retention capacity rate that can reach as high as 87.8%) and exceptional rate performance (252.1 and 207.8 mAh g−1, respectively, at 8 A g−1). Furthermore, full cells assembled by pairing Ti3C2Tx@FeS2/NiS and Ti3C2Tx@FeSe/NiSe with Na3V2(PO4)3 cathodes also demonstrate excellent cycling performance, with both configurations achieving up to 500 cycles. The suggested approach enables efficient utilization of byproducts from Lewis acidic etching, expanding possibilities for synthesizing high-performance anodes in sodium-ion batteries consisting of MXene and TMCs.

Para-Azaquinodimethane-based Quinoidal Copolymers: Significant Enhancement of Electrochemical Performances and Stability With Conformational Planarity

para-Azaquinodimethane-based Quinoidal Copolymers: Significant Enhancement of Electrochemical Performances and Stability With Conformational Planarity

Transition metal-assisted layer-by-layer binder free deposition for high-performance energy storage devices

The increasing energy demands of the world necessitate the development of advanced energy storage systems. Hybrid supercapacitors (HSCs) have emerged as promising candidates, combining the high specific power density (PS) of supercapacitors (SCs) with the high specific energy density (ES) of batteries (BATs). However, its performance is dependent on the properties of electrode materials, which need enhancements in conductivity, surface area, and electrochemical stability. In this study, we utilized magnetron sputtering technique for exploring the potential of interface engineering to improve the electrochemical performance of tungsten disulfide (WS2) as a battery grade electrode material by incorporating chromium (Cr) and titanium (Ti) as an interfacial layer. This strategic modification significantly increased the conductivity, charge transfer efficiency, and structural stability of the WS2 electrode. Electrochemical experimentation in both half-cell and full-cell configurations revealed that the WS2/Cr and WS2/Ti electrode exhibits superior CS [2400 and 3800] F/g, respectively compared to pristine WS2. Fabricated WS2/Cr//AC and WS2/Ti//AC attained ES [95 and 117] Wh/kg and PS [6800 and 8500] W/kg, respectively. The outcomes from the electrochemical testing further demonstrated the superior cyclic stability of WS2/Cr//AC and WS2/Ti//AC with [96.5 and 98.3] % which shows that Cr and Ti as an interfacial layer not only mitigates the limitations of WS2 but also enables the devices to achieve higher performance metrics, underscoring the critical role of interface engineering in advancing HSCs technologies.