Absorption Properties Research Articles

High-entropy ferrite with tunable magnetic properties for excellent microwave absorption

High-entropy ferrite with tunable magnetic properties for excellent microwave absorption

Regulatory mechanism of the microstructure, water absorption, and release properties of internal curing phosphogypsum-based aggregates by silica fume

Regulatory mechanism of the microstructure, water absorption, and release properties of internal curing phosphogypsum-based aggregates by silica fume

Theoretical study on one- and two-photon absorption properties of several axially substituted titanium phthalocyanine derivatives

Theoretical study on one- and two-photon absorption properties of several axially substituted titanium phthalocyanine derivatives

Improving the water absorption properties of bacterial cellulose by in-situ and ex-situ modifications for use in CMC-graft-sodium acrylate superabsorbent

Improving the water absorption properties of bacterial cellulose by in-situ and ex-situ modifications for use in CMC-graft-sodium acrylate superabsorbent

High efficiency microwave absorption properties of α−SiCp/α−SiCnw/SiO2/C composites with multi−interface hybrid SiC nanowires prepared by heterogeneous nucleation−growth mechanism

High efficiency microwave absorption properties of α−SiCp/α−SiCnw/SiO2/C composites with multi−interface hybrid SiC nanowires prepared by heterogeneous nucleation−growth mechanism

Ultra-thin thickness electromagnetic-wave absorption property and excellent corrosion resistance in weak-magnetic FeCr0.5NiCu0.5 high-entropy alloy

Ultra-thin thickness electromagnetic-wave absorption property and excellent corrosion resistance in weak-magnetic FeCr0.5NiCu0.5 high-entropy alloy

Interfacial magneto-electric synergistic strategy for enhancing microwave absorbing properties of barium hexa-ferrite by polyaniline surface modification and La-doping activation

Interfacial magneto-electric synergistic strategy for enhancing microwave absorbing properties of barium hexa-ferrite by polyaniline surface modification and La-doping activation

Co-Ni/C Composite Derived from N, S-Codoped Graphene Decorate Metal-Organic Framework toward Microwave Attenuation.

Metal-organic frameworks (MOFs) exhibit highly adjustable porosity, structure, and versatility, properties that render them promising for electromagnetic wave (EMW) absorption applications. However, the impedance matching of these composites is poor in practical applications, thereby compromising their EMW absorption performance. In this study, a novel EMW absorbing composite was synthesized by a solution-thermal method combined with a subsequent pyrolysis process. Specifically, we introduced heteroatom (N and S) codoped graphene (N, S-Gr) into the Co-Ni MOF, forming N, S-Gr/CoNi/C. Graphene was endowed with abundant defect and disorder sites through the codoping of nitrogen and sulfur, which enhanced interfacial polarization and dipole polarization. When nickel and cobalt were added in a 1:1 ratio, the minimum reflection loss (RLmin) of the N, S-Gr/Co-Ni/C composite reached -47.7 dB at 4.24 GHz, and the resultant material exhibited the best absorption properties. As a result, this composite is considered to be an ideal candidate for the development of highly effective EMW absorbers.

A novel cellulose-derived graphite carbon/ZnO composite by atomic layer deposition as an over-wideband microwave absorbent.

It is a major challenge to obtain broadband microwave absorption (MA) properties using low dielectric or magnetic nanoparticle-decorated carbon composites due to the limited single conductive loss or polarization loss of the carbon materials used as substrates. Novel pure cellulose-derived graphite carbon (CGC) materials can be used as an exceptional substrate option due to their special defective graphitic carbon structure, which provides both conduction and polarization loss. Herein, CGC@ZnO composites were first synthesized by atomic layer deposition (ALD) for use as microwave absorbents. Thanks to the multiple interfaces composed of graphitic carbon, defective carbon, and polar ZnO molecules, the CGC@ZnO composites exhibited superior MA properties. Specifically, the CZ-3 achieved a minimum reflection loss (RLmin) of -50.5 dB (over 99.999% MA) at 6.16 GHz in 2.98 mm. Amazingly, the maximum effective absorption bandwidth (RL < 10 dB, EABmax) could reach up to 6.48 GHz at only 1.59 mm. The ultra-broadband absorption property is mainly attributed to its strong electromagnetic attenuation capability and excellent impedance matching, making it one of the most promising materials for MA applications.

Enhancing mechanical and erosive properties of hybrid polymer composites using synergistic fiber-filler interactions

This study explores the mechanical, water absorption, and erosive wear properties of hybrid polymer composites reinforced with treated hemp, carbon, and basalt fibers. The composites were fabricated using the hand lay-up method, with epoxy resin as the matrix and fillers (CaCO3 and coconut fiber) incorporated to enhance performance. Treated hemp fibers underwent 5% NaOH treatment to improve fiber-matrix adhesion, and ASTM standards were followed for tensile, flexural, and impact tests. Water absorption was monitored over 10 days, and solid particle erosion was assessed under varying impingement angles. Results showed that Sample B2 (20% treated hemp, 6% basalt) exhibited superior mechanical properties, including flexural strength (15% higher than comparable samples) and impact resistance (10% higher). Treated fibers and fillers minimized water absorption, while erosion resistance was maximized in carbon-basalt composites. SEM analysis confirmed uniform fiber dispersion and strong interfacial bonding in optimal samples, leading to improved load transfer and mechanical stability. This study demonstrates the potential of hybrid composites as high-performance materials for automotive, aerospace, and construction applications, emphasizing the critical role of balanced fiber composition and chemical treatments in optimizing material properties.

FRET-based mesoporous organosilica nanoplatforms for in vitro and in vivo anticancer two-photon photodynamic therapy.

We report the synthesis of multifunctional periodic mesoporous organosilica nanoparticles (PMO NPs) with substantial two-photon absorption properties and targeting capability for two-photon excitation fluorescence (TPEF) and photodynamic therapy (TPE-PDT). Prepared using an adapted sol-gel synthesis, the nanoplatforms integrated two silylated chromophores in their three-dimensional matrix to maximize non-radiative Förster resonance energy transfer from a high two-photon absorption fluorophore donor to a porphyrin derivative acceptor, leading to an enhanced generation of reactive oxygen species. Combinations of biodegradable and non-biodegradable bis(triethoxysilyl)alkoxysilanes were employed for the synthesis of the NPs, and the corresponding photophysical studies revealed high efficiency levels of FRET. Next, the cellular uptake and toxicities of pristine and functionalized NPs were evaluated on breast cancer cell lines upon TPEF and TPE-PDT. Notably, the use of TPE-PDT treatment led to high levels of phototoxicity on MCF-7 and MDA-MB-231 cancer cells with substantial effects when compared to one-photon excitation (OPE)-PDT treatment. Preliminary in vivo data on selective and biodegradable NPs showed a significant phototoxicity towards MDA-MB-231 on zebrafish xenograft embryos, making these advanced nanoplatforms promising candidates for future TPE-PDT-based cancer treatments.

First-principles study of the effect of Bi content on the photocatalytic performance of bismuth bromide oxide-based catalysts.

A comprehensive analysis of BixOyBrz has been carried out using first-principles density-functional theory (DFT) to explore the electronic structure, energy band structure, and essential properties related to its photocatalytic performance. DFT calculations reveal that BiOBr, Bi4O5Br2, Bi12O16Br5, Bi24O31Br10, Bi3O4Br, and Bi5O7Br have different indirect bandgap values of 2.46 eV, 2.51 eV, 1.67 eV, 2.21 eV, 2.21 eV, and 2.87 eV, respectively, and these differences reflect the influence of material composition and structure on its electronic structure. When analyzing their optical characteristics, we observe that the dielectric function's real and imaginary components show peaks in the low-energy regime, indicating a material that is more responsive to light in these energy ranges. The absorption spectra show that the BixOyBrz material absorbs the highest amount of UV light absorption, and as the ratio of Bi to Br changes, the absorption spectra exhibit a red shift, which enhances the material's visible light absorption and thus improves the utilization of light. These light absorption properties make BixOyBrz materials potentially advantageous for enhancing photoelectric conversion efficiency, which is particularly important for producing microelectronic and optoelectronic devices.

Transparent broadband metamaterial absorber based on a multilayer ITO structure

In this paper, a multilayer optically transparent metamaterial absorber (OTMA) with microwave broadband absorption properties based on indium tin oxide (ITO) and polydimethylsiloxane (PDMS) is designed. The electrical resonance and magnetic resonance generated by the ITO resonance structure of the upper and middle layers make the absorption rate of OTMA exceed 90% at 6.2 GHz-24.6 GHz. The proposed OTMA has polarization insensitivity and wide-angle absorption properties. The experimental results verified that the OTMA has good absorption properties. The absorber has potential application prospects in stealth device windows and electromagnetic shielding structures.

Enhancement of optoelectronic performance by plasmonic effect in TiO2-rGO/Ag-TiO2 based on UV detectors

Abstract In this paper, the plasmonic effect in UV detectors based on titanium dioxide (TiO2) and reduced graphene oxide (rGO) is investigated. The studies have shown that a TiO2-rGO nanocomposite material is obtained by the method of hydrothermal synthesis. The addition of silver nanoparticles (NPs) and Ag- TiO2 core-shell nanostructures (NS) leads to the plasmonic effect and an increase in the optoelectronic parameters is observed. The TiO2-rGO images were obtained with the help of SEM, Raman spectroscopy found the ratio ID/IG. AFM images showed the morphology surface of the rGO. rGO sheets are visible in the SEM and AFM images. Hydrothermal synthesis results in a long-term reduction of rGO, i.e. the amount of oxygen-containing groups decreases. Raman spectroscopy shows the presence of peaks characteristic of the starting materials. The absorption properties when adding plasmonic nanoparticles to the films show changes in the absorption spectrum in the visible region of light, due to the transparency of rGO.&amp;#xD;The current-voltage characteristics show that the presence of plasmonic particles in the nanocomposite material leads to an increase in the photoinduced current of about 94 μA, which is almost 3.0 times greater. When irradiated, the multicomponent nanocomposite material with plasmonic nanoparticles responds to light three times faster than TiO2- rGO. The obtained results can be used in the development of new light-sensitive devices for optoelectronic and photocatalytic applications.&amp;#xD;

Suckling Rat Pup Model: Do Caprine Milk Lactoferrin and Immunoglobulins Have Different Digestion and Absorption Properties from That of Human and Bovine Species?

This study aimed to investigate the digestion and absorption properties of caprine milk serum proteins in comparison to human and bovine species by using rat pups to mimic preterm infants. The results indicate that caprine lactoferrin (LTF) had a shorter retention time in the intestine and released a greater number of fragments, resembling human milk LTF more closely. In contrast, caprine immunoglobulins (Igs) were similar to bovine Igs and both exhibited a longer retention time in the intestine. For absorption, caprine Igs could be absorbed intact, which was similar to human and bovine Igs, whereas caprine LTF fragments were found in jejunum but not in plasma of rat pups. This is similar to bovine LTF but differed from human LTF as human LTF could be absorbed intact in plasma of rat pups at 20 min. In addition, the absorption rate of peptides and amino acids from caprine milk serum was similar to that of human milk serum, which was higher than that from bovine milk serum. This study aimed to enhance our understanding of the differences in bioavailability of LTF and Igs derived from caprine, human milk, and bovine milk, thereby offering guidance for selecting protein sources for premature infants.

Synergistic study of electromagnetic and mechanical properties of broadband star-shaped negative Poisson's ratio wave-absorbing structures

Abstract Multi-functional integrated sandwich composite structures have excellent wave-absorbing and energy-absorbing properties, and show great potential for application in a variety of fields, including civil, military and aerospace. In this study, the optimal Latin hypercube sampling strategy is used to reveal the coupling mechanism between the electromagnetic and mechanical properties of three key design parameters (height, core tilt, and wall thickness) of the SANPR structure by means of absorbing and mechanical numerical modelling. The results show that due to the combined effect of structural effect, dielectric loss and magnetic loss, the optimum balance between wave absorption and mechanical properties is achieved in the space of specific design dimensional parameters when the height is 12.05 mm, the core inclination is 30.13° and the wall thickness is chosen to be 2 mm. The minimum reflection loss (RLmin) is -25.51 dB, the effective absorption bandwidth (EAB) is 12.71 GHz (&lt;-10 dB), the specific energy absorption (SEA) is 33.39 J/g, and the densification strain (DS) is 0.5. At the same time, the SANPR rotating configuration achieved a minimum reflection loss of -50.22 dB and a specific energy of 106.41 J /g. This study can provide a reference for the design and development of new stealth devices.&amp;#xD;

Thermal annealing effects on optical and dielectric properties of TiOPc thin films for optoelectronic and photonic applications

Abstract Titanyl phthalocyanine (TiOPc) is a metal phthalocyanine compound with interesting electronic and catalytic properties, making it useful in various applications. This study investigates the effects of thermal annealing on the optical and dielectric properties of vacuum-evaporated TiOPc films. The optical and structural characteristics were examined before and after annealing. FTIR spectra show a correlation between the peak positions of the films before and after the annealing process. Additionally, the spectra of the annealed sample show a decrease in C=O and the formation of a coordination bond between the Ti dopant and the phthalocyanine molecule. X-ray diffraction shows an amorphous behavior before and after annealing for TiOPc films. The AFM images show the presence of peaks and valleys of varied sizes. This leads to enhanced light trapping and scattering, improving light absorption and optical properties of the film. Thermal annealing at 473 K for 2 h resulted in a significant reduction in the optical energy gap, with E g1 decreasing by approximately 7% (from 1.58 eV to 1.47 eV) and E g2 by about 6% (from 3.0 eV to 2.83 eV), which indicates the thermal stability of these films. Moreover, the real part of dielectric constants reached appreciable improvements of about 30% at low frequencies. These changes are ascribed to the decreased structural defects and enhanced molecular ordering induced by annealing. The thermal stability of TiOPc films and improvement in the performance of optoelectronic devices such as photodetectors and optical switches by applying TiOPc films can be understood from these explorations. Moreover, the simple and cost-effective vacuum evaporation and annealing fabrication enable large-scale industrial production that would be attractive for application engineers to fully utilize these films in practice.

Near-neutral pH sensing by azoheteroarene dyes.

We serendipitously discovered a novel series of azoheteroarene dyes capable of detecting pH variations in near-neutral solutions. These dyes feature thiazole, thiadiazole, triazole, pyrazole, or benzothiazole heteroaryls linked to hydroxyphenyl azo groups. They exhibit distinctive light absorption properties in aqueous solutions and show notable color changes in a narrow pH range, visible to the naked eye. Both experimental data and quantum calculations suggest a plausible mechanism for their function as pH indicators. Additionally, these azoheteroarene dyes effectively monitor pH in complex environments, and we show their use for detecting the pH change of culture medium containing growing cancer cells.

Advancements in 2D Titanium Carbide (MXene) for Electromagnetic Wave Absorption: Mechanisms, Methods, Enhancements, and Applications.

With the advent of the 5G era, there has been a marked increase in research interest concerning electromagnetic wave-absorbing materials. A critical challenge remains in improving the wave-absorbing properties of these materials while satisfying diverse application demands. MXenes, identified as prominent "emerging" 2D materials for wave absorption, offer unique advantages that are expected to drive advancements and innovations in this field. This review emphasizes the synthesis benefits provided by the unique structural characteristics of MXenes and the performance enhancements achieved through their combination with other absorbing materials. Material requirements, synthesis approaches, and conceptual frameworks are integrated to underscore these advantages. The study provides a thorough analysis of MXene-absorbing composites, going beyond basic classification to address preparation and modification processes affecting the absorption properties of MXenes and their composites. Attention is directed to synthesis techniques, structural design principles, and their influence on composite performance. Additionally, the potential applications of MXenes in electromagnetic wave absorbing devices are summarized. The review concludes by addressing the challenges currently confronting MXene materials and outlining expected developmental trends, aiming to offer guidance for subsequent research in this domain.

Hybrid CIGS-Cobalt Quaterpyridine Photocathode with Backside Illumination: A New Paradigm for Solar Fuel Production.

Chalcogenide-based thin-film solar cell optimized for rear illumination and used for CO2 reduction is presented. Central to this innovation is a thinner, Cu(In,Ga)S2 chalcopyrite absorber coated with a robust metallic top layer, which potentially surpasses the performance of conventional front-illuminated designs. Using cobalt quaterpyridine molecular catalyst, photocurrent densities for CO2 reduction exceeding 10 mA/cm2 at 0.0 V vs. RHE under 1 Sun illumination, and ca. 16 mA/cm2 at -0.25 V vs. RHE were achieved in voltammetry experiments. Controlled potential electrolysis showed catalytic activity over 20 h with selectivity for CO ranging from >92 % (first 4 hours) to 86 % at the end of the experiment. This approach opens limitless possibilities for employing various reduction catalysts, extending far beyond CO2 reduction. It imposes minimal constraints on absorption properties, immobilization methods, and catalyst nature, setting the stage for high-performance, adaptable PEC devices.