Search Results (9,708)

Flexible supercapacitors have emerged as pivotal energy storage components in wearable smart electronic systems, owing to their exceptional electrochemical performance. However, the widespread application of flexible supercapacitors in smart electronic devices is significantly hindered by the developmental bottleneck of high-performance anode materials. In this study, a novel electrode composed of surface-modified Fe₂O₃ nanoneedles uniformly coated with a polypyrrole (PPy) film and anchored on Co-MOF-derived N-C nanoflake arrays (PPy/Fe₂O₃/N-C) is designed. This composite electrode, grown in situ on carbon cloth (CC), demonstrated outstanding specific capacity, rate performance, and mechanical flexibility, attributed to its unique hierarchical 3D arrayed structure and the protective PPy layer. The fabricated PPy/Fe₂O₃/N-C@CC (P-FONC) composite electrode exhibited an excellent specific capacitance of 356.6 mF cm⁻² (143 F g⁻¹) at a current density of 2 mA cm⁻². The current density increased to 20 mA cm⁻², and the composite electrode material preserved a specific capacitance of 278 mF cm⁻² (112 F g⁻¹). Furthermore, the assembled quasi-solid-state Mn/Fe asymmetric supercapacitor, configured with P-FONC as the negative electrode and MnO₂/N-C@CC as the positive electrode, demonstrated robust chemical stability and notable mechanical flexibility. This study sheds fresh light on the creation of three-dimensional composite electrode materials for highly efficient, flexible energy storage systems. Full article

This study aims to determine the electrochemical performance of FeWO₄ (Fe), NiFeOOH (Ni), and FeWO₄/NiFeOOH (FeNi) electrodes in 0.1 M Na₂SO₄ and 0.1 M NaOH electrolytes, highlighting the impact of SO₄²⁻ and OH⁻ ions. Nyquist analysis demonstrated that the FeWO₄/NiFeOOH electrode had the lowest charge transfer resistance, indicating superior charge transport and capacitive performance over the individual electrodes. In Na₂SO₄, SO₄²⁻ ions stabilized double-layer capacitance and enhance ionic mobility. Conversely, in NaOH, highly conductive and mobile OH⁻ ions significantly improved charge transfer and diffusion, making NaOH more effective for electrochemical applications. Tafel analysis revealed better charge transfer kinetics and greater energy efficiency in NaOH, with the composite electrode excelling in both electrolytes. Linear voltammetry showed a synergistic interaction between FeWO₄ and NiFeOOH, achieving a photocurrent density of 6.70 mA·cm⁻² in NaOH under illumination, an 830.56% increase over Na₂SO₄. Additionally, the FeWO₄/NiFeOOH composite electrode exhibited longer electron lifetimes in NaOH than in Na₂SO₄, attributed to the smaller ionic radius and higher diffusion coefficient of OH⁻ ions. Pulsed photocurrent analysis revealed notable improvements in photocurrent generation and stability in NaOH. These findings indicate that the FeWO₄/NiFeOOH composite is a highly efficient and stable material for advanced energy technologies, with NaOH providing optimal performance conditions. Full article

To address the critical applications of heterogeneous structures involving nickel-based superalloys (IN718) and copper alloys (CuSn10) under extreme operating conditions, and to address the limitations of traditional joining techniques in terms of interfacial brittleness and geometric constraints, this study employs Laser Powder Bed Fusion (LPBF) technology, specifically multi-material LPBF (MM-LPBF). By precisely melting IN718 and CuSn10 powders layer by layer, the study directly fabricates multi-material IN718/CuSn10 joint specimens, thereby simplifying the complexity of traditional joining processes. The research systematically investigates the interfacial microstructure and mechanical property evolution laws and underlying mechanisms. It reveals that sufficient element diffusion and hardness gradients are present at the IN718/CuSn10 interface, indicating good metallurgical bonding. However, due to significant differences in thermophysical properties, cracks inevitably appear at the interface. Mechanical property tests indicate that the strength of the IN718/CuSn10 joint specimens falls between that of IN718 and CuSn10, but with lower elongation, and fractures primarily occur at the interface. This research provides theoretical support for establishing a process database for LPBF formed of nickel–copper heterogeneous materials, advancing the manufacturing technology of aerospace multi-material components. Full article

Our research aims to determine the optical properties of binary composites based on TiO₂ and SiO₂ oxides combined with additional metal oxides such as CuO and SrO. The inclusion of CuO and SrO together with TiO₂ and SiO₂ nanoparticles is driven by their ability to introduce intermediate energy levels in the forbidden band, acting as electron traps that reduce the recombination rate and increase the efficiency of solar conversion. Morphological and structural characterization of the materials was carried out to evidence the homogeneity of the final composite materials as well as their high specific surface area. Additionally, an extensive characterization of the optical properties was performed, revealing that the optical parameters of the studied samples depend on their composition. The results indicate that the optical performance of TiO₂-CuO and SiO₂-SrO composites is significantly superior to that of the pure sample. Therefore, these materials are proposed as promising candidates for enhancing the efficiency of solar cells. Full article

Irbesartan (IRB) is a commonly used BCS Class II antihypertensive drug requiring dissolving capacity enhancement to address oral bioavailability limitations. In this work, seven new IRB salts were successfully synthesized, including one carboxylate (IRB-MAL) and six sulfonate salts (IRB-TOSA, IRB-BSA, IRB-4-CBSA, IRB-2, 5-CBSA, IRB-MSA, and IRB-CPSA). Their vitro dissolution, intrinsic dissolution rates (IDRs), thermal/hygroscopic stability (via thermal analysis, dynamic vapor sorption, and accelerated stability tests), and phase transition process (monitored by in situ Raman spectroscopy) were evaluated. The results revealed that IRB-TOSA, IRB-MAL, IRB-BSA, IRB-4-CBSA, and IRB-MSA salts exhibited IDRs of 0.3194–0.7383 mg/(cm²·min), all significantly higher than IRB, with dissolution concentrations increased by 14.9–113.6%. IRB-TOSA and IRB-4-CBSA salts demonstrated excellent hydrothermal stability. Single crystal structure analysis confirmed proton transfer from coformers’ sulfonic/carboxylic acids (deprotonation site, H-out) to IRB’s diazaheterocycles (protonation site, H-in) in IRB salts. Six sulfonate salts exhibited N_H-in–H···O_H-out and N_non-H-in–H···O_H-out hydrogen bonds, with the former absent in IRB-MAL. Furthermore, supramolecular synthon studies revealed distinct hydrogen-bonding patterns (e.g., bifurcated bonds in 2,5-CBSA and CPSA salts) that correlate with moisture resistance. Quantitative analysis of IRB salts suggested hydrogen bond strengths may influence their melting points (decomposition temperatures). This study demonstrates that IRB salts hold promise for advanced pharmaceutical applications. Full article

The continuous growth of energy-efficient electronic devices and compact systems has motivated researchers to develop TFTs based on p-type semiconductors. This review examines the developments in p-type thin-film transistors (TFTs) processed using solution methods to achieve integration with complementary metal–oxide–semiconductor technology. Improving organic p-type materials is critical for achieving advanced mobility and stability characteristics with suitable process integration. Scientists study these materials for use in wearable devices which display mechanical strength when fitted onto a curve. This review presents an exclusive discussion about the wide spectrum of applications which involve flexible displays and sensors, together with upcoming technologies such as artificial skin and flexible integrated circuits. The article examines present material challenges, along with device reliability and large-scale production methods, to give a thorough analysis of solution-processed p-type TFTs toward their broad implementation in upcoming electronic devices. By summarizing the developments and most recent studies in the field, this review aims to provide useful information regarding current research into and future trends of p-type TFTs. Full article

The common alkaloid theophylline (Tph) is known to exist in five polymorphic forms. The structures of its 8-halo analogues were previously unreported. Here, we report three polymorphs for 8-chlorotheophylline (8-Cl-Tph) and an additional distinct one for 8-bromotheophylline (8-Br-Tph). While polymorphs for theophylline are dominated by NH---N inter-molecular hydrogen bonds, the halo compounds exclusively exhibit NH---O interactions. 8-Cl-Tph has two related structures with chains N(7)-H(7)---O(2); one is also the stable form for 8-Br-Tph. Polymorphs with a dimeric R₂²(10) ring structure using N(7)-H---O(6) H-bonds exist for all three compounds, though each with distinct 3D packing. DFT calculations indicate that the alkaloid ring nitrogen N(9) is a weaker base in 8-halo compounds, disfavoring NH---N interactions in their polymorphic forms. Full article

The application techniques and composition of green and blue-green pigments in the Maijishan Grottoes were explored by utilizing microscopic observation, Raman spectroscopy, and SEM-EDX analysis. For the first time, lavendulan and high-purity botallackite were identified in these grottoes, in addition to the commonly found malachite and atacamite. These discoveries suggest that several caves in the Maijishan Grottoes were originally painted in blue-green tones, which have since altered to the current green or dark green hues. It was also revealed that the application of green mixed pigments involved layering malachite over basic copper chloride, rather than blending them together. Moreover, variations in the composition and placement of white ash layers indicate that the use of mixed pigments was likely due to repainting rather than initial decorative purposes. These findings significantly enhance our understanding of ancient painting techniques and provide crucial data for the conservation and restoration of cultural heritage in the Maijishan Grottoes. Full article

The spiro compound, 5,5′-dimethoxy-1,3-bis(3-(trifluoromethyl)phenyl)-3,3a-dihydro-1H-spiro[cyclopenta[a]indene-2,2′-indene]-1′,8(3′H,8aH)-dione (4), was synthesized and identified by NMR spectroscopy, mass spectrometry, and X-ray crystallography. Compound 4, C₃₆H₂₆F₆O₄, was crystallized in the triclinic space group P-1with the cell parameters a = 8.8669(5) Å, b = 10.5298(8) Å, c = 17.0135(11) Å, α = 91.396(2)°, β = 90.490(2)°, γ = 109.235°, V = 1499.14(17) ų, Z = 2. In an asymmetric unit, two molecules are packed by short contacts to form an inversion dimer. The molecules are linked into chains along the a- and b-axis directions by additional short contacts in the crystal. Compound 4 was synthesized by the dimerization of (E)-5-methoxy-2-(3-(trifluoromethyl)benzylidene)-2,3-dihydro-1H-inden-1-one (3). (E)-5-Methoxy-2-(3-methoxybenzylidene)-2,3-dihydro-1H-inden-1-one (5), one of the analogs of compound 3, was compared with compound 4 based on in vitro experiments, DFT calculations, and an in silico docking study. The HOMO/LUMO energy difference and binding energy difference between the two compounds are consistent with the results obtained from an in vitro assay where 4 showed a better effect than 5. To evaluate the biological activity of 4, we examined its inhibitory effects on Early Growth Respone-1 (EGR-1)-regulated gene expression in HaCaT keratinocytes. Treatment of cells with 4 reduced interleukin-4 (IL-4)-induced thymic stromal lymphopoietin (TSLP) mRNA levels, as revealed by reverse transcription-polymerase chain reaction and quantitative real-time PCR. Furthermore, the electrophoretic mobility shift assay demonstrated that 4 inhibited IL-4-induced DNA binding of EGR-1 to the promoter region of the TSLP gene. Full article

BaTiO₃ (BTO), a lead-free chalcogenide ferroelectric material, has emerged as a promising candidate for ferroelectric memories due to its advantageous ferroelectric properties, notable flexibility, and mechanical stability, along with a high dielectric constant and minimal leakage. These attributes lay a crucial foundation for multi-value storage. In this study, high-quality BaTiO₃ ferroelectric thin films have been successfully prepared on STO substrates by pulsed laser deposition (PLD), and Pt/BaTiO₃/SrRuO₃/SrTiO₃ ferroelectric heterojunctions were finally prepared by a combination of UV lithography and magnetron sputtering. Characterization and performance tests were carried out by AFM, XRD, and a semiconductor analyzer. The results demonstrate that the ferroelectric heterojunction prepared in this study exhibits excellent ferroelectric properties. Furthermore, the device demonstrates fatigue-free operation after 10⁷ bipolar switching cycle tests, and the polarization value exhibits no significant decrease in the holding characteristic test at 10⁴ s, thereby further substantiating its exceptional reliability and durability. These findings underscore the considerable promise of BTO ferroelectric memories for nonvolatile storage applications and lay the foundation for the development in the fields of both in-memory computing systems and neuromorphic computing. Full article

As an advanced surface modification technology, laser cladding technology can significantly improve the hardness, wear resistance, and corrosion resistance of the base material by forming a high-performance composite coating on the surface of the substrate. In this paper, In718 nickel-based high-temperature alloy was used as the substrate, and laser cladding technology was used to prepare In718/(2Nb + 1SiC) composite coatings, and the effects of different laser powers (800 W, 1200 W, 1600 W, and 2000 W) on the microstructure and wear-resistant properties of the coatings were systematically investigated. Through SEM morphology observation, EDS elemental distribution analysis, wear behavior characterization, wear mechanism discussion, the regulatory mechanism of laser power on the microstructure evolution, the uniformity of reinforced phase distribution, and the coating properties were revealed. The results show that different melting powers significantly affect the phase structure and the generation of reinforcing phases in the In718/(2Nb + 1SiC) composite coatings. A 1200 W laser input power can make the coatings reach the optimal phase structure equilibrium. Both properties of the SiC-reinforced phase are retained, and a large number of NbC- and MoC-reinforced phases are generated. This results in excellent properties for the coating. Full article

The crystal chemistry of syngenite K₂Ca(SO₄)₂·H₂O and its lattice dynamics under low and high temperatures and high pressure were studied. The research facilities used include in situ temperature variable single-crystal (SCXRD) and powder X-ray diffraction (PXRD), in situ PXRD under high pressure (HP), thermal analysis (DSC and TGA), and Raman spectroscopy. For the first time, a detailed study of syngenite in the range of negative temperatures down to −180 °C was performed. It indicates the absence of phase transitions in the range from −180 °C to 240 °C. The largest expansion of the structure is observed along the α₁₁, which is consistent with the layered architecture. The minor thermal expansion along the α₂₂ is observed in the plane of the [Ca(SO₄)₂]²⁻ layer, formed by the bassanite-type chains. The study of powder samples at HP up to 20 GPa was carried out using synchrotron radiation and a diamond anvil cell. The phase transition is registered at 10 GPa. After the decompression, the syngenite post-phase becomes partially amorphized. Full article

As key components in solid-state electrolytes, lithium salts influence the electrochemical window, ionic conductivity, and ultimately the full battery’s performance. To reduce the selection time and costs while providing electric and molecular level insights into the interactions of elements and components in solid polymer electrolytes, this paper proposes a rapid screening method based on Density Functional Theory (DFT). The structure stability, electrochemical stability, and ionic conductivity of eight common inorganic and organic lithium salts were systematically investigated by analyzing five parameters: formation energy, band gap, Li⁺–anion dissociation energy, anion–PEO binding energy, and anion diffusion barriers along PEO chains. Through a comprehensive analysis of these parameters obtained from DFT, LiTFSI has been identified as the most suitable lithium salt. The electrolytes fabricated by LiTFSI exhibited better performance. This approach, characterized by its rapidness, efficiency, and low cost, provides a viable method for screening lithium salts in developing solid-state batteries. Full article

The rate of nucleation of crystals is the subject of extensive research, since it—together with the nucleation time—determines the number of crystals growing; in turn, their number is related to their size. Experimental studies show that, for biomolecular crystals, despite the required unusually high supersaturations, the nucleation process is distinctly slow. This slowness arises from the inherent peculiarity of the nucleation of such crystals. Therefore, a prerequisite for management of the crystallization process towards the desired outcome is the molecular level understanding of the nucleation mechanism. In this paper, analyzing the mechanisms behind the nucleation process of protein crystals, it is argued that the highly inhomogeneous molecule surface is the main reason for the slow crystal nucleation: only a few small patches on their surface are capable of forming crystalline bonds. Therefore, the partner proteins must not only be brought to encounter one another but must also find each other’s binding site. In turn, this requirement imposes a severe steric restriction on the association of protein molecules, which, however, is alleviated by a rotational-diffusional reorientation. This is why particular attention is paid to this aspect of the protein crystal nucleation process. Full article