Nanomaterials最新文献

The rapid advancements in the field of two-dimensional (2D) materials have significantly influenced the development of innovative sensor technologies [...].

This review focuses on the research progress related to carbon dots (CDs) derived from Chinese herbal medicines and tea, covering preparation methods, physicochemical properties, and application fields. It elaborates on preparation approaches like hydrothermal, solvothermal, microwave-assisted, and ultrasonic-assisted methods, and their influence on CDs' structure and properties. It also explores CDs' structural and optical properties. The application fields include antibacterial, sensing, bioimaging, photocatalysis, hemostasis, and energy. Carbon dots show antibacterial activity by destroying bacterial cell membranes, they can detect various substances in sensing, are important for bioimaging, degrade organic pollutants in photocatalysis, have hemostatic and anti-inflammatory effects, and can be used as battery anode materials. Despite progress, challenges remain in improving yield, quantum yield, property control, and understanding their mechanism of action. This review provides a reference for related research and looks ahead to future directions.

Viticulture, the science of growing, cultivating, and harvesting grapes, and enology, the art and science of making wine, are rapidly evolving through innovative approaches aimed at improving the quality and efficiency of grape and wine production. This review explores the emerging use of nanoparticles, in particular gold, silver, and magnetic nanoparticles, to improve the quality, safety, and sustainability of both grape growing and winemaking processes. The unique properties of these nanoparticles, such as their small size, high surface area, and distinct chemical properties, enable them to address key challenges within the industry. In viticulture, nanoparticles have shown potential in protecting vines from pathogens, optimizing grape yield, and improving quality. In enology, nanoparticles are making a significant contribution to microbial control, reducing spoilage and refining wine analysis techniques, leading to improved product quality and safety. This review also highlights the synergy between different types of nanoparticles and their diverse applications, from microbial control in wine production to their use in innovative packaging solutions. In addition, nanoparticles have the potential to reduce dependence on agrochemicals and improve the sustainability of wine production, which is a promising avenue for future research. However, the integration of nanoparticles in viticulture and enology also poses regulatory and safety challenges, including the potential for nanoparticles to leach into wine products. Further research and regulatory advances are essential to ensure the safe and effective use of these technologies in winemaking. Overall, nanoparticles offer significant benefits to the wine industry, driving improvements in efficiency, sustainability, and quality.

Inherent material loss is a pivotal challenge that impedes the development of metamaterial properties, particularly in the context of 3D metamaterials operating at visible wavelengths. Traditional approaches, such as the design of periodic model structures and the selection of noble metals, have encountered a plateau. Coupled with the complexities of constructing 3D structures and achieving precise alignment, these factors have made the creation of low-loss metamaterials in the visible spectrum a formidable task. In this work, we harness the concept of deep learning, combined with the principle of weak interactions in metamaterials, to re-examine and optimize previously validated disordered discrete metamaterials. The paper presents an innovative strategy for loss optimization in metamaterials with disordered structural unit distributions, proving their robustness and ability to perform intended functions within a critical distribution ratio. This refined design strategy offers a theoretical framework for the development of single-frequency and broadband metamaterials within disordered discrete systems. It paves the way for the loss optimization of optical metamaterials and the facile fabrication of high-performance photonic devices.

Aliphatic polycarbonate (PC) can be readily hydrolyzed by lipase, but bisphenol A-derived PC (i.e., BPA-PC) lacks enzyme catalysts for their efficient hydrolysis due to the high hydrophobicity and rigidity of its polymer backbone. This study aims to develop an artificial nanozyme for the selective hydrolysis of small-molecule aromatic carbonates as model substrates for BPA-PC. The catalyst is prepared through molecular imprinting of cross-linkable micelles in a one-pot reaction using a thiourea template and a zinc-containing functional monomer. The resulting water-soluble nanoparticle resembles a hydrolytic metalloenzyme to bind the appropriately shaped aromatic carbonate substrate in the active site, with the nearby zinc acting as a cofactor to activate a water molecule for the nucleophilic attack on the carbonate. Catalytic hydrolysis is observed at room temperature and pH 7, with a rate acceleration of 1 × 10⁶ for diphenyl carbonate.

An integrated quasi-vertical double-diffused MOSFET (DMOS) with split-gate trench (SGT) structure (SGT-QVDMOS), whose specific ON-state resistance (R_ON,sp) breaks the traditional Si limit significantly, is proposed and fabricated. The measured data of the latest manufactured device is presented. By introducing the vertical gate poly, the split grounded source poly, and the asymmetric thick oxide in the gate trench, the traditional lateral drift region is folded in the SGT-QVDMOS. In this way, the device voltage withstanding mode transforms from one dimension to two dimensions, including the horizontal and the vertical directions. Combining the electric field modulation effect and the reduced lateral area, which benefit from the quasi-vertical structure, the forward conducting characteristic of the SGT-QVDMOS is effectively improved. According to the measured results from the SGT-QVDMOS manufactured by the 180 nm Bipolar-CMOS-DMOS (BCD) process, the ultralow ON-state resistance is obtained. The device achieves 1.9 V V_TH, 11.07 mΩ∙mm² R_ON,sp, and 48.6 V BV, which is 39.0% lower than the traditional Si limit.

The pursuit of efficient and sustainable hydrogen production is essential in the fight against climate change. One important method for achieving this is the electrolysis of water, particularly through the oxygen evolution reaction (OER). Recent studies indicate that trimetallic layered double hydroxides (LDHs) can enhance OER performance compared to bimetallic LDHs. This improvement occurs because the third cation alters the electronic structures of the other two cations, thereby increasing the intermediates' binding energies and enhancing electrical conductivity. This study proposes an approach enabling the modulation of the electronic structures of all three cations involved in the synthesis of the trimetallic LDHs. It suggested intercalating sodium dodecyl sulfate (SDS) into the interlayer of the trimetallic NiFe-La-LDH. A successful intercalation of SDS has been confirmed through the XRD, FT-IR, EDS, and XPS. This has expanded the interlayer distance which was beneficial for the electrical conductivity. Furthermore, SDS generated sulphur, which modulated the electronic structures of all three cations enriching the active sites and improving electrical conductivity and OER performance compared to its counterparts. This approach is beneficial: 1. The interlayer can be further enlarged by using different doping ratios of SDS. 2. Sulphur can enrich the active sites and improve the OER performance.

We analyze theoretically an InGaN/GaN n-i-p diode with a single quantum well supporting only one bound state. The bottom parts of the diode, namely the first barrier and the quantum well, are heavily n-doped with silicon at 5 × 10¹⁹ cm^-3 to ensure a high electron concentration in the well. The voltage drop in the diode occurs in the second AlGaN barrier, which is undoped, and structure ends with a p-doped GaN. The band structure of the diode is calculated by a Schrodinger-Poisson drift-diffusion solver. Next, we calculate the absorption from the bound state in the well to the "continuum" above the well. We show the oscillatory behavior of the spectrum, with the amplitude decreasing with more negative voltage applied to the diode. Oscillations are due to interferences of the wavefunctions between the edges of the well and the slope of the potential barrier.

Metal-organic framework (MOF)-derived carbon, which contains metal nanoparticles embedded in a carbon matrix, is becoming an important group of catalysts. We report the synthesis of tungsten carbide-carbon nanocomposites using a similar concept, i.e., by pyrolysis of organotungsten compounds under high-temperature and high-pressure conditions. We characterized the product using various analytical techniques and examined its electrocatalytic activity. Two precursors, Bis(cyclopentadienyl)tungsten (IV) dichloride (Cp₂WCl₂) and Bis(cyclopentadienyl)tungsten (IV) dihydride (Cp₂WH₂) were pyrolyzed at 4.5 GPa and 600 °C. Tungsten carbide (β-WC_1-x) crystals with a size of 2 nm embedded in graphitic carbon were formed from Cp₂WH₂-derived samples. Electrochemical measurements showed that all samples were active in the oxygen reduction reaction (ORR), with the Cp₂WH₂-derived sample having the best catalytic performance.

Hydroxyapatite (HAp) is widely used in biomedical applications due to its biocompatibility, osteoconductivity, and bioactivity. However, its low mechanical strength, tendency toward rapid corrosion, and lack of bactericidal properties present significant limitations in applications. This study aimed to improve the properties of HAp by reinforcing it with multi-walled carbon nanotubes (MWCNTs) and doping it with silver nanoparticles (AgNPs) and silver-core selenium-shell nanoparticles (Ag@SeNPs). Ocimum basilicum extract was used as both a reducing and stabilizing agent in the synthesis of nanoparticles using an environmentally friendly and non-toxic method as an alternative to traditional methods. The synthesized HAp, HAp/MWCNT, Ag-HAp/MWCNT, and Ag@Se-HAp/MWCNT nanocomposites were characterized by TEM, SEM, XRD, Raman spectroscopy, and BET analysis. BET analysis showed a reduction in surface area from 109.4 m²/g for pure HAp to 71.4 m²/g, 47.5 m²/g, and 35.3 m²/g for HAp/MWCNTs, Ag- HAp/MWCNTs, and Ag@Se-HAp/MWCNTs, respectively. Antimicrobial activities against P. aeruginosa, E. coli, S. aureus, E. faecalis, and C. albicans were evaluated. HAp and HAp/MWCNT did not show any antimicrobial activity, while Ag-HAp/MWCNTs showed inhibition zones of 14 mm for Escherichia coli and 18 mm for Pseudomonas aeruginosa at 5 mg/mL. Ag@Se-MWCNTs/HAp exhibited superior efficacy with inhibition zones of 18 mm, 12 mm, and 20 mm for S. aureus, E. faecalis, and Candida albicans, respectively. The incorporation of Ag@SeNPs enhanced HAp's antibacterial and antifungal properties through a synergistic mechanism.