Journal of Science: Advanced Materials and Devices最新文献

Nanomaterials for suitable particle sizes, shapes, surface properties, biocompatibility, magnetic properties, and chemical stability are candidates for biomedical applications. Among these nanomaterials, iron-based ones are highly interested in their morphological and magnetic properties for potential utilizations in biomedicine. However, iron-based nanoparticles lose their chemical stability in body fluids because of their oxide formations and transformations. Their use in biomedical applications, especially in imaging, may be less effective if they are oxidized and have lower magnetization values. Thus, the idea of coating them with a protective layer has recently emerged to prevent magnetic nanoparticles from degrading in human fluids and losing their magnetic properties. However, the biological effects of these coated nanoparticles on human cells are poorly understood. In this paper, the synthesis of multilayer graphene (MLG) encapsulated iron-based nanoparticles was investigated by solvothermal and chemical vapor deposition (CVD) methods followed by purification. Subsequently, their surface modification was conducted with pyrene end-functional POEGMA obtained by atom transfer radical polymerization (ATRP). Cytotoxicities of synthesized nanoparticles were evaluated in MCF7 cell lines, which is a commonly used model for breast cancer research. We also compare the results with those obtained from bare iron oxide nanoparticles (IONPs) and iron oxides that were embedded in reduced graphene oxide (rGO) or partially coated with it. We aim to evaluate the safety and efficiency of these nanoparticles and increase their chemical stability as a multifunctional nano platform for cancer diagnosis and treatment. Characterization techniques such as XRD, XPS, SEM, TEM, DTA/TG, DLS, zeta potential, BET, NMR, FTIR, and VSM were performed on the nanoparticles. Cytotoxicity assessments on MCF-7 cell lines indicated the potential of these graphene-based magnetic nanoparticles for biomedical applications, particularly drug delivery, due to their small size, soft ferromagnetic properties, high chemical stability, and cytocompatibility at concentrations below 500 μg/mL over short incubation times.

The high temperature flow data of TiB₂/2024 aluminum matrix composites (referred to as TiB₂/2024 alloy) was investigated using a Gleeble-3500 thermal simulation testing machine. The experiments were conducted at various deformation temperatures (573 K, 623 K, 673 K, and 723 K), strain rates (0.01s⁻¹, 0.1s⁻¹, 1s⁻¹, and 10s⁻¹), and a maximum deformation of 60%. By comprehensively accounting for the deformation conditions, the relationships between the material parameters α, n, S, f of TiB₂/2024 alloy and the deformation temperature, strain, and strain rate were determined, leading to the modification of the Arrhenius model. A constitutive model for TiB₂/2024 alloy was constructed using the Gene expression programming (GEP) approach. The flow stress of TiB₂/2024 alloy during the compression process was predicted using both the modified Arrhenius model and the GEP model. The statistical analysis was performed to evaluate the prediction accuracy of the two models, and the extended stress-strain data was implemented in finite element simulations of the hot compression process. The results indicate that the flow stress of TiB₂/2024 alloy is significantly affected by the strain rate and temperature during the deformation process. The flow stress decreases with increasing temperature and increases with increasing strain rate. Both the modified Arrhenius model and the GEP model can effectively predict the alloy's flow stress. However, the modified Arrhenius model exhibits greater prediction accuracy than the GEP model.

This study proposes strategies to enhance the conversion of mechanical energy to electrical energy in cylindrical electromagnetic induction-type vibration energy harvesters (VEH) using disc or ring-shaped magnets and ring-shaped coils. The rationale behind these strategies has been substantiated by an analysis of magnetic flux gradients based on simulations. In particular, the utilization of a repulsive magnet pair and a yoke has been proposed to maximize the magnetic flux gradient at the coil winding position by manipulating the magnetic flux path. Simulation results confirm that the use of a yoke can produce a nearly 5.8-fold increase in power consumption at the external load. Additionally, the study demonstrates that the positioning and thickness settings of the coil are critical for improving the electrical output based on the spatial distribution of the magnetic flux gradient. Within the same magnet topology, points where power generation is not feasible due to a zero magnetic flux gradient are identified, besides a nearly 5.3-fold increase in observed power generation depending on coil placement. Given the structural feasibility of VEH implementation, a design for a moving magnet VEH utilizing ring magnets with a yoke enclosure is proposed, demonstrating that it can generate power at nearly 85% of the level attributed to using disc magnets.

This work reported a successful observation of the synergistic rapid antibacterial activity of the Electrospun PAN/PCL Nanofiber (NF) with Cuprous Oxide -based Quantum Dots (QDs). Our findings reveal that the NF-QDs nanostructure exhibits excellent antibacterial activity that eliminated more than 98% of antimicrobial-resistant bacteria in 30 s under visible light. The characterization including X-ray diffraction (XRD), scanning electron microscopy (SEM), Transmission electron microscopy (TEM), UV–Vis spectrophotometer (UV–Vis), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), Brunauer-Emmet-Teller (BET) analysis exhibits good physicochemical properties of both synthesized quantum dots and nanofiber. A desired hydrophobic NF with an average surface roughness of 219.40 nm and 243.46 nm for NF–Cu2O and NF–Cu₂O/TiO₂ was achieved with an average diameter of 502.54 nm and 343.02 nm, respectively. The antibacterial activity was tested against antibiotics-resistance strains, Klebsiella pneumoniae and Methicillin-resistant Staphylococcus aureus, as well as non-resistance strains, Escherichia coli and Staphylococcus aureus. Our results indicate the promising potential of NF-QDs as antibacterial fabric to halt antibiotic resistance infections and mitigate outbreaks in various sectors.

Radio frequency identification (RFID) is an emerging technology that has a crucial role in many areas. To be suitable for these applications, RFID tags must be flexible, which presents greater manufacturing challenges. Printing as an additive manufacturing method is preferred over subtractive processes due to its efficient use of materials and environmental friendliness. This review presents key properties of the printed patterns, namely electrical conductivity, layer thickness, and surface morphology. It links them to the reading distance between the RFID tag and the reader. The types of conductive inks and their role in achieving a long-read distance of flexible antennas are also discussed. The properties of flexible substrates linked to the printing process are also presented. These substrates were classified into paper, polymer, and textiles. This article considers two laboratory-scale printing techniques commonly used in research: inkjet and screen printing. The printing parameters of these printing techniques that affect the printing quality are covered. Furthermore, electroless plating is presented as a metallization process or a complementary method to other printing techniques.