Materials Letters最新文献

This study explores the hydrogen permeation resistance of Al-Si-Mg and Al-Si-Mg-Sr coated 22MnB5 boron steel in hot-press-forming. The Al-Si-Mg coating exhibits structural changes and Mg segregation, replacing the oxide layer. Sr addition is found segregated at the surface, further transforming the oxide layer. These modifications improve hydrogen permeation resistance, reducing both reversible and irreversible hydrogen permeation during hot-press-forming. Mg or Sr addition presents promising avenues for enhancing hydrogen permeation resistance in steel, potentially extending the service life of ultra-high-strength steel.

This work provides a contrastive analysis of Sb distribution in Sn-57Bi-1Sb solder by WDS mapping, EDS count map and EDS net map. The mapping analysis on the same region shows that the WDS mapping provides the more accurate data on the distribution of Sb compared with EDS analysis, including the concentration gradient of dissolved Sb and the fine SnSb particles with size less than 1 μm. WDS equipped with the enhanced spectral resolution is a critical technique to separate the complex overlap spectrum, which was recommended for the Sb detection in Sb-doped solders.

In this study, iron-rich steel slag (IRSS) and carbon fiber (CF) were incorporated into foam concrete to maximize the economic benefits of composites and multifunctional integration while improving the overall performance of foam concrete. The study found that the optimal IRSS content for maximizing foam concrete’s compressive strength was 15 %, which increased by 18.59 % compared to the control. Additionally, S15 specimens showed a 37.87 % increase in electrical conductivity compared to the control. In addition, the average value of the fundamental part of the dielectric constant of the S15 specimen was 7.409, the average value of the imaginary part was 3.057, and the angular tangent of the electrical loss (tanδ_ε) value and the reflection loss were both improved, which indicated that the S15 specimen material had a better ability to absorb electromagnetic waves and had an excellent performance of electromagnetic loss.

At room temperature, organic molecules undergo continuous rotation, driven by rotational barriers lower than k_BT. However, consensus regarding the impact of organic molecule rotation on carrier dynamics remains elusive, as conventional research methods struggle to distinguish between organic molecule rotation and inorganic frame vibrations. This study successfully achieved the goal of modulating the rotation rate of organic molecules by adjusting the relative atomic mass of nitrogen atoms. In the investigation of carrier dynamics, the rotational rate of organic molecules served as the sole independent variable. The findings indicate that a slower rotation rate correlates with an extended carrier lifetime. This correlation is attributed to the heightened charge separation and reduced motion of nuclei. This research provides valuable insights for prolonging the carrier lifetime of organic–inorganic hybrid perovskites.

Removal of bacteria from biological contaminated water is of great importance to the control of waterborne diseases. Herein, a simple and green method to purify bacterial infectant water was developed using two food supplements. Tea polyphenol (TP)/F127 complex was proved to remove nearly all bacteria from contaminated water by centrifugation. Without facilities, gravity sedimentation could isolate most of bacteria with high efficiency. The hydrogen bonds induced the formation of oleaginous precipitation composed of TP, F127, and bacterial cells with hydrophilic interior to encapsulate bacteria and hydrophobic surface against bacteria leaking out. The good biosafety of sedimentation agents, easy operation and common facilities implied this method could be used as a convenient approach to water purify, especially in the wilds and developing countries.

Nanostructured materials, defined by their distinctive physicochemical properties at the nanometer scale, facilitate the innovation of sophisticated applications through their inherent size-dependent phenomena and surface characteristics. In this study, we explore the synthesis of ZnSe nanostructures with distinct spherical and flower-like morphologies by varying the concentration of Ethylenediamine tetraacetic acid (EDTA). Our findings reveal that higher concentrations of EDTA facilitate flower-like morphologies, which provide a large surface area desired for gas sensing applications. Herein, the as-synthesized ZnSe nanostructures were applied for ammonia (NH₃) sensing at room temperature at different concentrations to evaluate their performance. The results obtained indicate that ZnSe nanostructures with flower-like morphology exhibit superior sensing capabilities, demonstrating a good response (ΔR/R_air)% of 71 % compared to the 61 % response observed for spherical ZnSe nanostructures for 20 ppm NH₃ gas, measured at room temperature. Additionally, the flower-like ZnSe nanostructures show significantly enhanced response and recovery times, demonstrating their potential as efficient materials for NH₃ detection at room temperature.

Piezoelectric properties of polycrystalline AlN films are strongly dependent on the texture of the material. For a number of applications, such as microelectromechanical systems (MEMS) and acoustic resonators, it is important to have a well-defined (0 0 2) orientation of the crystallites. Using an original method of selective deposition of graphene-like films (GLFs) followed by a simple, safe and efficient chemical vapor deposition (CVD) of AlN, we clearly demonstrate that the GLF sublayer does enhance the texture quality of AlN columnar structures. The improved crystal orientation along the (0 0 2) direction for AlN film grown on GLFs is locally visualized using a scanning electron microscope (SEM) and quantitatively reinforced using Raman spectroscopy.

Urea-formaldehyde (UF) resin has a high annual output, but the used and waste UF resin poses a challenge for recycling due to the difficulty in effectively decomposition them. In this study, A novel one-step degradation method was proposed, i.e., using eco-friendly malic acid and hydrogen peroxide to degrade cured UF resin residues using carboxylic acid through the hydrothermal oxidation method (HPMA), which was proved to have high cured UF resin degradation efficiency. This method will offer a new path for effectively recycling the UF resin out of service.

The combination of more than one clinical technique has been increasingly explored to improve imaging diagnosis, suppressing the limitations of individual procedures. Quantum dots (QDs) have been associated with paramagnetic complexes (GdDOTA) to develop optical-magnetic nanoprobes for imaging techniques. Herein, we report the preparation of bimodal nanoprobes by conjugating fluorescent QDs with GdDOTA complexes through dative bonds. These nanoprobes showed an enhancement in their emission intensity compared to bare QDs. Moreover, the nanosystems exhibited r₁ values up to 69% higher than the clinical GdDOTA. Therefore, the bimodal systems demonstrated promising performance for both optical and magnetic resonance imaging, exhibiting potential as bimodal contrast agents.

As a nickel-based alloy, GH4169 has the properties of excellent corrosion resistance, high temperature oxidation resistance and high creep resistance. In this paper, the compression creep behaviors of cylinder entangled wire materials (CEWMs) made from metal wires (GH4169 nickel-based alloy, 304 stainless steel) were investigated at elevated temperatures (from 400 °C to 500 °C). The performance degradation of the two materials was evaluated by the variation amplitude of four mechanical properties parameters and material characterization methods. The results indicated that both of 304 CEWMs and GH4169 CEWMs suffered a significant performance degradation at elevated temperatures, and both of the two CEWMs showed a much serious performance degradation above 450 °C (tempering temperature). Compared to the 304 CEWMs at the tested temperatures, the GH4169 CEWMs obtained better creep resistance. It is therefore concluded that the GH4169 CEWM is an excellent material that can replace the commonly used 304 CEWM at elevated temperature work conditions.