Micro & Nano Letters最新文献

This research explores the desorption mechanism and thermal stability of octadecyltrichlorosilane (OTS, CH₃(CH₂)₁₇SiCl₃) coating on quartz slides and in alkali-metal vapour cells. The morphological thermal-changes, energy dissipation diversity, and anti-relaxation characteristic of OTS coatings before and after exposure to Cs atoms by Fourier transform infrared spectroscopy, water contact angle measurement, atomic force microscopy imaging, collision energy dissipation analysis, and free induction decay of Cs atoms are measured systematically. The results show that the OTS coatings exhibit the best thermal stability under the specific process conditions, and the homogeneous and dense structure makes the adsorption of alkali-metal atoms more stable, which effectively reduces surface energy dissipation and prolongs the relaxation time of Cs atoms. The study provides certain reference for efficient anti-relaxation coating fabrication and coated cell application.

The emission of CO toxic gases seriously endangers environmental safety and human health. At present, the use of catalysts for catalytic oxidation of CO has become the mainstream research direction. In this study, CuO@TiO₂ catalysts with different ratios were prepared by solvent hydrothermal method, and the effects of reaction pretreatment temperature and other factors on the catalytic oxidation performance of CO were investigated. The experimental results show that the catalyst can achieve 100% conversion of CO at 115°C under the condition of pretreament at 350°C for 2 h. This excellent performance is due to the uniform distribution of the active component on the surface of the TiO₂ support, and the large pore structure constructed by the solvent hydrothermal method enhances the adsorption and activation of CO. This work provides an idea for the preparation of CO oxidation catalysts.

5-Fluorouracil (5-FU) is a chemotherapeutic agent widely used to treat different types of cancers. However, many patients present with obstacles during treatment due to 5-FU drug resistance. To overcome these drawbacks, a novel drug-loaded nanocarrier (NC) comprising titanium dioxide (TiO₂) nanoparticles surface functionalized with 5-FU to facilitate drug delivery is developed. This study designs and evaluates the antitumour effects of NCs in oral cancer (OC) cell lines of lymphoid origin. NCs were synthesized by biofunctionalization of TiO₂ nanoparticles with 3-aminopropyl triethoxysilane (APTES) which was then loaded with 5-FU. in vitro drug release was determined at three different pH values. The effect of chemotherapy was studied in mono- and co-culture systems comprising OC cells and human gingival fibroblasts (hGFs). From these studies, it is noted that after 24 h in an acidic medium (pH 5.5), more than 80% of 5-FU was released compared to that at basic pH. The cytotoxicity was higher when 5-FU was combined with the system TiO₂-APTES, in comparison with 5-FU alone was used. The drug-loaded NC showed an increased antitumour effect in the OC cell line with minimal cytotoxicity to hGFs. The anticancer effect of TiO₂/5-FU could be highly effective in the tumour microenvironment.

In the current work, CeO₂-NPs were produced via a green chemistry process via Linum usitatissimum seeds extract as the stabilizing agent. The CeO₂-NPs were characterized by the results of analytical techniques such as TGA/DTA, FTIR, UV–vis, XPS, XRD, and FESEM/PSA/EDX. The outcomes of the XRD pattern affirmed the crystalline structure of this product with the suggested size of about 20 nm, while the FESEM/PSA pictures presented spherical morphology. Additionally, the XPS analysis of CeO₂-NPs affirmed the presence of a Ce⁺³ oxidation state in the sample, as well as Ce⁺⁴ as the major valence of cerium oxide. The results of the MTT test on Huh-7 cancer cells and HFF normal cells displayed the lack of any significant cytotoxicity even at concentrations up to 1000 µg/mL. Therefore, the obtained synthesized CeO₂-NPs through this green method could be suggested as a prospective agent for medical applications due to its non-toxic effects.

The Internet of Things (IoT) and portable electronic devices are pivotal in enhancing living standards, with battery efficiency and compact design being critical for these devices. Analogue sensors, integral to advanced artificial intelligence, often necessitate complex real-time processing and actuation. This study examines the performance of one-dimensional armchair graphene nanoribbons in graphene nanoribbon field-effect transistors (GNRFETs). It compares graphene nanoribbon-based triple cascode operational transconductance amplifiers (GNRFET-TCOTAs) with conventional CMOS-based TCOTA. The results reveal substantial enhancements in the GNRFET-based TCOTAs: the pure GNR-TCOTA variant shows a remarkable 33.8% increase in DC gain and significant improvements in transconductance, slew rate, and gain-bandwidth, with enhancements of 8.48, 5.85, and 8.56 times, respectively. Furthermore, the pure GNRFET TCOTA exhibits higher speed, lower energy-delay product, and settling time compared to Si-CMOS-based TCOTA. The study also investigates the impact of critical design parameters on circuit performance. Overall, the research highlights the potential of GNRFETs to optimize TCOTA circuits, offering a path towards more efficient and compact electronic devices, thereby advancing the state of nanoelectronics and supporting the growth of high-performance IoT systems.

In this study, ZnCo₂O₄/Ag₃PO₄ composite catalyst was prepared by the precipitation method, and their performance in the photocatalytic degradation of methyl orange (MO) was studied. The catalysts were characterized by scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, selected area electron diffraction, X-ray photoelectron spectroscopy, and UV-Vis diffuse reflectance spectroscopy. The results indicate that the 0.1 ZnCo₂O₄/Ag₃PO₄ composite system has good photocatalytic activity in the degradation of methyl orange. Under simulated sunlight conditions, the degradation rate can reach 94% after 30 min. The maximum reaction rate constant of 0.1 ZnCo₂O₄/Ag₃PO₄ was 0.05301 min⁻¹, which is 3 times and 52 times the rate constant of pure Ag₃PO₄ and pure ZnCo₂O₄, respectively. In catalyst recycling experiments, 0.1 ZnCo₂O₄/Ag₃PO₄ still degraded methyl orange at a rate of 84.4% after three cycles. Trapping experiments showed that holes and superoxide radicals mostly contributed to the photocatalytic degradation of methyl orange by the catalyst, while hydroxyl radicals played a partial role. The energy level structure of ZnCo₂O₄/Ag₃PO₄ is conducive to the effective separation of photogenerated electrons and holes, improving the lifespan of photogenerated charges. In the investigated catalyst series, 0.1 ZnCo₂O₄/Ag₃PO₄ demonstrated the best photocatalytic performance.

Traditional tertiary oil recovery methods are fraught with challenges such as significant reagent adsorption, voluminous injection requirements, limited sweep efficiency, and inadequate intelligent targeting. These issues lead to suboptimal displacement of residual oil, resulting in the inability to mobilize substantial crude oil resources and thus yielding low recovery rates. Microcapsules—spherical particles with micron or nanometer scale diameters—have been extensively utilized across various sectors, including food storage, targeted drug encapsulation, and fragrance containment, owing to their distinct advantages in controlled release, isolation, and targeted delivery. These applications have successfully achieved industrialization and commercialization. In recent years, numerous researchers have explored the application of microcapsule preparation processes to diverse facets of oil extraction, with the aim of further enhancing oil recovery (EOR). This article elucidates the mechanism of action of microcapsules, their preparation methods (encompassing in situ polymerization, interfacial polymerization, spray drying, solvent evaporation, phase separation, and supercritical CO₂-assisted techniques), characterization and evaluation methodologies, among other aspects. It encapsulates the current status and principal challenges associated with the application of microcapsule preparation processes in oilfield development and probes the potential and pivotal research directions for their oilfield applications.

The paper proposes a single antenna that can generate dual-mode plane spiral orbital angular momentum (PS-OAM) beams. Six Vivaldi antennas placed in a tangential circular array make up the antenna, and the antenna is etched onto a substrate material and has a flat design, allowing for easy integration with other system components. The neighbouring ports of the antenna elements have phase differences, so phase-shifting in the feeding network is unnecessary. When fed with the same phase and amplitude, the antenna can produce PS-OAM beams with mode +1 at 7 GHz and mode +2 at 14 GHz, and the measured purity is 80.6% and 63%, respectively. The method may provide a new way to produce multi-mode orbital angular momentum.

The tribological behaviors of nanoparticles (NPs) have attracted widespread attention in the fields of nano-lubrication and ultra-precision manufacturing. The frictional and dynamic behaviors of SiO₂ NPs acting with the single asperity were studied on silicon surface utilizing atomic force microscope. The friction forces of NPs, both static and kinetic, exhibit an initial decrease followed by an increase as the normal load increases (0–300 nN). The nonmonotonic load-dependence of friction behavior corresponds to the dynamic transformation of “sliding-rolling-sliding” motion state of the manipulated NPs, which can be predicted by a Double-Hertz model and further confirmed by nanoindentation-marked NPs. This research has a significant implication for regulating dynamic behaviors of NPs in contemporary three-body abrasive tribology.

Nitrogen and phosphorus co-doped porous carbon plate (NPCP) was prepared by simple pyrolysis carbonization and alkali activation of biomass duckweed NPCP displays the largest specific surface area (SSA) of 2023 m² g⁻¹, and is rich in pyridine N and P doping, which makes the metal-free carbon have excellent electrocatalytic oxygen reduction performance. The best NPCP2 shows a half-wave potential of 0.19 V vs. Ag/AgCl in alkaline electrolyte, and its activity is equivalent to that of commercial platinum carbon (Pt/C). In addition, it shows excellent methanol toxicity resistance and continuous catalytic stability. The experimental results show that the heteroatom doping method obtained by biomass hydroponics has great advantages and great application value in the catalytic field of porous carbon materials.