Absorption Efficiency Research Articles

Coal gangue as an efficient absorber for X-band applications

Coal gangue as an efficient absorber for X-band applications

Enhanced SWIR Absorption in PMMA‐Coated TiN‐Based Metamaterial

AbstractAchieving highly efficient absorption in the short wavelength infrared (SWIR) spectral region is crucial for advancing numerous technologies. SWIR absorption enhances energy harvesting in solar cells, improves the sensitivity of infrared sensors, and enables precise control of thermal radiative properties in thermal emission devices. These advancements are essential for applications such as thermal imaging, night vision, and thermophotovoltaic systems. The study presents a simple, cost‐effective design of a polymer‐coated multilayer perfect absorber (MPA) metamaterial optimized for the SWIR spectral region. The proposed MPA structure is composed of four distinct layers: a top layer made of polymethyl methacrylate (PMMA) polymer, a second layer featuring arrays of circular titanium nitride (TiN) disks, a dielectric middle layer consisting of a pure zinc oxide (ZnO) film, and a bottom metallic layer formed by a thin film of TiN. The results demonstrate that the MPA achieves near‐perfect absorption, with a remarkable 99% efficiency centered at a wavelength of 1.3 µm. The absorption properties are further investigated with respect to various structural parameters to ensure better performance of the absorber. These absorbers hold great promise for applications in energy absorption, infrared sensing, thermal emission, and related fields.

MOFs-derived copper selenides nanoparticles implanted in carbon matrix for broadband electromagnetic wave absorption

Selenide-based functional composites materials demonstrated tunable dielectric properties and heterogeneous interface design, which has been widely studied in electromagnetic (EM) wave absorption field. Herein, Metal-organic frameworks (MOFs) derived carbon coating copper selenide (Cu2-XSe@C) composites were successfully fabricated by using the Cu-MOFs as precursor. After reacting with the gaseous Se in the selenization annealing process, the metal host was converted into the Cu2-XSe nanoparticles, where embodied in the carbon matrix transformed from the organic linker. Based on the tunning dielectric property and building heterogeneous interface, MOFs-derived Cu2-XSe@C composites displayed outstanding EM wave absorption performance. Though the conduction loss, interfacial and dipole polarization behaviors, the minimum reflection loss (RLmin) value of Cu2-XSe@C-600 composites reached to −74.3 dB at 11.7 GHz when the thickness is 2.0 mm. The efficient absorption bandwidth (EAB) can be regulated via controlling the applied thickness. When the thickness is 2.3 mm, above-mentioned Cu2-XSe@C-600 got the broadest absorption performance with the EAB of 5.5 GHz from the 7.7–13.2 GHz, covering the whole X-band. Therefore, MOFs-derived selenide-based composites shed a new design strategy for constructing broadband EM wave absorption, especially in radar stealth applications.

An ultrathin ultralight electromagnetic absorber based on shortcut glass-coated amorphous magnetic Fiber/Salisbury-like screen

A structural design methodology is proposed for an ultrathin, ultralight, and absorption-adjustable electromagnetic absorber. The proposed absorber (SFSL) consists of an absorbing layer with shortcut glass-coated amorphous magnetic fiber and a substrate layer with transmitting material. This absorber features a Salisbury-like screen structure and incorporates multiple loss mechanisms. By investigating the influence of fiber distribution, length, content, and substrate layer thickness on absorption performance, it has been determined that the weight per square meter and thickness of a single-layer SFSL can be lowered within 50 g/m2 and 1.5 mm respectively. Furthermore, the absorption intensity and bandwidth can be adjusted by manipulating these parameters. The SFSL exhibits resonant behavior similar to that of a metamaterial absorber; however, SFSL with randomly distributed fibers demonstrates broader and stronger absorption characteristics in the frequency range from 2 to18 GHz. Additionally, the thicknesses of the substrate layer and surface covering affect the electromagnetic response characteristics. This work provides a simple strategy for constructing an ultrathin and ultralight composite to achieve efficient absorption of electromagnetic waves.

A conical spiral methanol steam reforming reactor for spectral splitting-based concentrating photovoltaic-thermochemical hybrid production

The spectral beam splitting (SBS) photovoltaic-thermochemical hybrid system improves the solar thermal energy grade through photon energy cascade distribution and methanol steam reforming (MSR) reaction. Given the deficiency of MSR reactor development for dish-concentrating SBS systems, the conical spiral structure is introduced to the receiver/reactor in this work, thus facilitating efficient absorption of circular beams and ameliorating the adaptability of the production. Based on specially designed spectral beam splitter, the Monte Carlo ray tracing (MCRT) method is employed to simulate the non-imaging optical process and optimized reflective cone structure. Thermodynamics and kinetic models of the reactor are established and experimentally validated. The analysis results show that the reflective cone advances the optical efficiency of the reactor to 76.95%, and the conical spiral structure helps to enhance heat and mass transfer for utilization of the catalytic space. The mid/low-temperature reaction prefers a solution flow rate of less than 1.53 mL·s-1 and a water-methanol ratio of 1.4-1.9, with the maximum solar thermochemical conversion rate of 54.5%. Moreover, the upgrading in photothermal and photovoltaic heat exceeds respectively 0.62 and 8.97 at less than 600 W·m-2 of irradiation, demonstrating the adaptive potential of the reactor. In summary, the research results contribute to broadening the operating conditions of the hybrid production and the full-spectrum penetration of solar energy in distributed scenarios.

Absorption and quantum efficiency of GeSn nanopillar arrays for infrared detectors

This research investigates the optical absorption and quantum efficiency of germanium-tin (GeSn) materials with a tin(Sn) content of 4.5%, and their potential applications in infrared optoelectronic systems. It has two forms which are crystalline(c-GeSn) and amorphous(a-GeSn) states. The finite-difference time-domain (FDTD) method was used to simulate the absorption of c-GeSn and a-GeSn. By optimising the period, radius and height of the nanopillars, the optimal parameters were determined, and it was found that the c-GeSn nanopillars in that case had a very stable and excellent absorption in the near-infrared (NIR) band. Calculated by MATLAB that the cylindrical nanopillars could reach a maximum quantum efficiency of 3.67% at 1350 nm. It is anticipated that this study will contribute to the further understanding of GeSn and provide a theoretical basis for designing high-performance infrared photodetectors.

Impact of Skin Decontamination Wipe Solutions on the Percutaneous Absorption of Polycyclic Aromatic Hydrocarbons.

Firefighter occupational exposures were categorized as a class 1 (known) carcinogen by the International Agency for Research on Cancer in 2022. As a result, firefighters have become heavily focused on identifying effective and easy to implement decontamination strategies to reduce their chemical exposures. Skin decontamination using wipes post-exposure is one decontamination strategy that every firefighter has available to them. However, firefighters have expressed concerns over the ingredients in the wipe solution increasing dermal absorption. The goal of this study was to determine if the ingredients in skin decontamination wipe solution had any enhancement effect on the dermal absorption of phenanthrene. To determine any enhancement effects, the additive solution of four skin decontamination wipe products was applied to porcine skin 15 min after chemical dosing. The absorption of phenanthrene was tested in vitro using a flow-through diffusion cell system over eight hours. The wipe solution effects on dermal absorption were determined by measuring multiple absorption characteristics including cumulative absorption (µg/cm2), absorption efficiency (% dose absorbed), lag time (minutes), flux (µg/cm2/h), diffusivity (cm2/h), and permeability (cm/h). No penetration enhancement effects were observed in any of the skin decontamination wipe solutions tested; rather, all wipe solutions decreased the absorption of phenanthrene. Slight differences in cumulative absorption among two pairings of skin decontamination wipe solutions, wipes 1 and 3 vs. wipes 2 and 4, were observed, indicating that some ingredients may impact dermal absorption. These findings show that firefighters should continue using skin decontamination wipes to reduce their dermal exposures to fireground contaminants with little concern of increasing the absorption of phenanthrene.

Crushing behavior and energy absorption of node self-locked Kagome honeycomb

This work proposes a self-locked Kagome honeycomb (SLKH) structure to realize better balance between energy absorption and cost efficiency. The structure uses a simple and creative bending preparation method to form a triangle nested self-locking pattern with distinct layers, rich shapes, easy assembly, flexibility and efficiency. The quasi-static experiments and numerical simulations are employed to investigate the energy absorption behavior and dynamic response. Numerical analysis is conducted to reveal the influence of cell size, angle at the connecting plate, and number of bent plates on the energy absorption performance of SLKH. Additionally, a theoretical estimation model for mean crushing force of SLKH structure is established, providing guidance for efficient parameter design and selection. The results demonstrate that the SLKH exhibits superior energy absorption performance with low cost.

Optimizing excited state adsorption and carrier dynamics of metal doped zinc oxide by p-d orbital modulation for efficient reverse saturation absorption

Doping metals can regulate the excited state adsorption and carrier transport efficiency of ZnO through p-d orbital coupling thereby improving its nonlinear performance. Herein, the thin film coatings consisting of ZnO, and M-ZnO (M=Al, Sn, Mg) were synthesized using the magnetron sputtering technique. ZnO exhibited the granular/stick structure, while the metal dopant atoms (M) were incorporated into the ZnO lattice, resulting in a homogeneous distribution. Photoluminescence spectroscopy reveals the quenched defect emission intensity, indicating a decrease in the rate of photo-induced electron-hole pair complexation. Mg exhibits an optimized effect to promote the saturation absorption of ZnO, resulting in the enhancement of the nonlinear absorption (NLA) coefficients for M-ZnO films. Al-ZnO and Sn-ZnO films exhibit reverse saturation absorption. Theoretical simulation shows that the additions of transition metal atoms favor the electron transfer through p-d orbital modulation of ZnO. The p-d hybridization causes the metal-d orbitals to cross the Fermi level and form an electron transport channel, thereby enhancing the excited state absorption, and effectively controlling the NLA process and mechanism. The excited state absorption of the M-ZnO films significantly rises. This research demonstrates that the optimization of excited state absorption through p-d orbital modulation is a highly effective strategy for the development of efficient and superior nonlinear optical absorbers.

Design and investigation of indium tin oxide-based transparent broadband microwave absorbers

This paper presents the design of a novel wideband transparent microwave absorber based on indium tin oxide (ITO). The absorber adopts a multilayer structure, with the top layer composed of a nested square structure made of ITO material, an intermediate dielectric layer of polyvinyl chloride (PVC), and a bottom layer of polyethylene terephthalate (PET) coated with ITO as the reflector. By optimizing structural parameters such as the thickness of the ITO film and the dimensions of the spacer layer, efficient broadband microwave absorption exceeding 90% is achieved within the frequency range of 2.43 to 5.67 GHz, while simultaneously meeting requirements for optical transparency and broadband performance. Simulation experiments and theoretical analyses demonstrate excellent polarization and incident angle stability of the absorber structure. Finally, samples are fabricated using screen printing technology, and free-space testing results are consistent with simulation predictions, validating the feasibility of the design.

Patterned 3D-graphene for self-powered broadband photodetector

The remarkable ultra-wideband energy capabilities of zero-bandgap two-dimensional (2D) graphene have made it an outstanding material for photon absorption and charge carrier generation across a broad spectrum. However, atomically thick 2D-graphene only exhibits a light absorption efficiency of 2.3%, posing a challenge for graphene-based photodetectors to harness photon energy effectively. This study utilized plasma-enhanced chemical vapor deposition technology and a mask to create in situ patterned 3D-graphene/Si-based Schottky heterojunctions. The porous structure and natural nano-resonant cavities of the 3D-graphene enhanced the probability of light absorption, while the curved and sharp edges and corners of the patterned 3D-graphene concentrated the local electromagnetic field and induced localized surface plasmon resonance. Both theoretical and experimental analyses confirmed the improved light absorption mechanisms and charge transfer of photogenerated carriers under the built-in electric field. The photodetector based on the patterned 3D-graphene/Si Schottky structure exhibits excellent broadband response characteristics spanning from 380 to 1550 nm, with responsivity and specific detectivity of 68.47 A/W and 1.43 × 1012 Jones at a wavelength of 1550 nm. Furthermore, the photodetector demonstrated ultrafast microsecond-level response times (116/120 μs rise/fall times) along with exceptional stability and reliability. The potential applications of as-fabricated photodetector include logic devices such as “AND” and “OR” gates and information encryption. This research holds valuable scientific significance for the design of future optoelectronic devices and provides crucial insights and technical support for developing high-performance Si-based graphene detectors.

High-Q all-dielectric metasurface perfect absorber powered by quasi-bound states in the continuum

All-dielectric perfect absorbers powered by quasi-bound states in the continuum (-BIC) are of great importance for developing high-performance optoelectronic devices because they provide high Q-factor absorption. However, these structures usually require the addition of metal back reflectors or degenerate critical coupling to achieve high absorption, which often introduces problems such as Joule heat output and sensitivity to geometrical parameters. In this work, we present an all-dielectric high Q-factor metasurface perfect absorber (MPA) with a cell structure consisting of split Si elliptical disks. By adjusting the tilt angle of the gap, the metasurface can excite a single quasi-BIC resonance in a highly reflective background, corresponding to the electric quadrupole (EQ) mode. Due to the asymmetric coupling of the EQ mode, the proposed metasurface easily breaks the 50% absorption limit. At the wavelength of 894.645 nm, the metasurface achieves a perfect absorption of more than 99% and has a Q-factor of up to 1955. In addition, the structure shows excellent tolerance to geometrical parameters while ensuring high absorption performance. By adjusting the polarization angle, we have also achieved an arbitrary tuning of the absorption efficiency without frequency shift. This work provides a viable scheme for the design of tunable, large-tolerance, and high-Q all-dielectric MPAs, which have a broad potential application in the fields of optical filtering, optical switching, and polarization detection.

Improvement of X-ray response of CZT films by post-annealing

CdZnTe (CZT) epitaxial films are promising for X-ray flat panel detectors due to their ability for large area fabrication, high absorption efficiency, and excellent detective quantum efficiency (DQE). However, challenges like image lag, ghosting, and reduced DQE due to long response times and high dark currents persist. This study introduces a novel post-in-situ annealing technique to enhance CZT film sensitivity and transient response. Results show that a brief 20 s annealing treatment increased surface Zn content, raising detector resistivity from 3.5 × 109 Ω·cm to 3.3 × 1010 Ω·cm while reducing leakage current at high voltages. This treatment also significantly reduced surface defects, improving CZT film detectors’ X-ray response time. Moreover, the electrons mobility-lifetime product (μτ)e improved from 2.30 × 10−5 cm2/V to 2.17 × 10−4 cm2/V, indicating enhanced charge carrier dynamics crucial for high-speed X-ray detection. Notably, the X-ray response sensitivity achieved a commendable 126 μC G−1· cm−2 a bias of 30 V. In conclusion, in-situ annealing represents a remarkable step forward in the development of CZT technology for X-ray flat panel imaging, addressing critical issues and potentially broadening its applications in medical and industrial imaging systems.

Making Activator Materials Active Carbon From Wedi Skin Salak (Salacca edulis Reinw) With ZnCl2 Activator as Adsorbent to Reduce Fenol Content

Making Activator Materials Active Carbon From Wedi Skin Salak (Salacca edulis Reinw) With ZnCl2 Activator as Adsorbent to Reduce Fenol Content. Wedi salak skin in Bojonegoro as an activated carbon material can provide an alternative for activated carbon manufacturing materials by utilizing environmentally friendly natural materials. The wedi salak skin is modified by treatment in the sun, in the roast, and in the oven in the manufacture of activated carbon which is then activated with ZnCl2 and then tested the adsorbs power of this salak skin activated carbon against phenol reduction. The adsorbent material that reduces the concentration of phenol the most is the roasted adsorbent material with a final phenol concentration of 2.15 mg/L so that the concentration of phenol absorbed is 297.85 mg/L at a mass of 1.5 g. The results of the analysis show that each variation of the activated carbon variation can reduce the concentration of phenol. The results obtained from this study are the type of activated carbon material whose highest absorption efficiency is the type of activated carbon material roasted at 99.28% with a mass of activated carbon of 1.5 g. Based on the results of the analysis, it can be seen that each variation of the type of activated carbon material will experience a decrease in concentration as the mass of the adsorbent increases. The greater the mass of the adsorbent, the adsorption ability will also increase. Each type of activated carbon material also experienced an increase in percent removal along with an increase in adsorbent mass. The results of research on the effect of activated carbon mass, also show that the adsorption capacity value decreases with increasing adsorbent mass. In this research data, the largest capacitance value was 112.87 mg/g at the smallest mass of 0.5g. The decrease in adsorption capacity is caused by the active side of the adsorbent that has not all bonded with the adsorbate.

NANOSTRUCTURE LIPID CARRIER TECHNOLOGY IN DRUG DELIVERY: ROUTE OF ADMINISTRATION, PREPARATION METHOD, CHARACTERIZATION, AND APPLICATION FOR ANTI-AGING

The new method, known as nanostructured lipid carrier (NLC) in drug delivery systems, has the potential to increase therapeutic efficacy, stability, and bioavailability. This systematic literature review aimed to provide a detailed summary of NLC technology in drug delivery systems, including routes of administration, preparation methods, characterization, and utilization for the delivery of anti-aging active ingredients in cosmetics. To collect scholarly articles on NLCs, we employed a systematic search method using Google Scholar and PubMed. After the screening process, 53 pertinent papers out of 102 articles were chosen for descriptive analysis. NLC exhibit significant promise in many drug delivery applications, including oral, topical, parenteral, and transmucosal routes, with many benefits, including improved bioavailability, stability, and drug penetration through the skin, cornea, and brain. Moreover, NLC technology has been effectively applied for the administration of drugs, including anti-aging drugs. Topical anti-aging preparations generally use synthetic or natural active ingredients. However, synthetic ingredients are often less stable and can irritate skin. NLC can protect and control the release of active ingredients, thereby reducing the risk of irritation. NLC can also improve the penetration of active ingredients into the deeper layers of the skin, allowing it to reach the dermis layer, which is responsible for most skin aging. The efficient absorption capacity of NLC technology in topical preparations presents new opportunities for anti-aging cosmetic product development owing to its effectiveness in skin penetration. Keywords: Nanostructured Lipid Carrier (NLC), drug delivery system, drug penetration, anti-aging

Facile Fabrication of Co-Doped Porous Carbon from Coal Hydrogasification Semi-Coke for Efficient Microwave Absorption.

A Co-doped porous carbon was successfully fabricated by a facile carbonizing procedure using coal hydrogasification semi-coke (SC) as the carbon and cobalt nitrate as the magnetic precursors, respectively. The mass ratio of the precursors was changed to regulate the microwave absorption (MA) capabilities. The favorable MA capabilities are a result of a synergistic interaction be-tween the dielectric loss from the carbon framework, the magnetic loss from nano-sized Co particles, and multiple scattering from the residual pores. At a thickness of 4.0 mm, the Co/C composite showed the lowest reflection loss of -33.45 dB when the initial mass ratio of cobalt nitrate and SC was 1:1. The effective absorbing bandwidth (EAB) could achieve 3.5 GHz at 2 mm thickness. This work not only opens up a new avenue for the facile fabrication of dielectric and magnetic loss combinations and their structural design, but it also creates a new route for the high value-added exploitation of SC.

A Miniaturized, Fuel-Free, Self-Propelled, Bio-Inspired Soft Actuator for Copper Ion Removal.

We present a novel miniaturized, gear-shaped, fuel-free actuator capable of autonomously propelling itself in an aquatic environment to absorb heavy metals, such as copper ions. While hydrogel-based absorbents are promising solutions for cationic pollutant remediation, their stationary nature limits their effectiveness in areas where contaminants are unevenly distributed. To address this, we developed a bio-inspired soft actuator that mimics natural propulsion mechanisms. The Marangoni effect, driven by its inherent chemical properties, demonstrated a self-propelled motion without requiring external fuel. The proof-of-concept actuator generated a plane motion lasting up to 2 h and swept over an area approximately 400 times bigger than its size. By harnessing the chemical and optical properties of the hydrogel, we efficiently removed and quantitatively analyzed copper ions through a colorimetric method. This innovative integration of self-propelled movement and efficient copper ion absorption underscores its potential for advancing miniaturized devices in environmental remediation, paving the way for more active and efficient pollutant removal systems in challenging aquatic environments.

Study on energy absorption of paper honeycomb sandwich tube filled by polyethylene foam under axial loading

This work proposed an approach to multi-component non-metallic materials, namely regular polygonal paper honeycomb sandwich tubes filled with polyethylene (PE) foam, and focused on the influence of drop impact parameters and structural parameters on the deformation characteristics and energy absorption of the filled tubes. Axial drop impact tests were employed to exert drop impact loading on cross-sections of the specimens with a square drop weight. The results showed that the X-direction filled tube (X-DFT) had a higher crushing strength and yield strength than that of the Y-direction filled tube (Y-DFT). As the tubular cross-section edge number of the filled tube increased, the specific energy absorption (SEA) and specific total efficiency (STE) decreased. Under the same axial drop impact loading conditions, the SEA and STE of the X-DFT were superior to those of the Y-DFT. As the edge number of the tubular cross-section or the tubular length ratio increased, the SEA and STE of the filled honeycomb tube decreased significantly. While the impact energy increased, the SEA and STE of the filled tubes increased approximately linearly. This work investigated the influence of drop-impact and structural parameters on deformation characteristics and energy absorption. It is expected to provide supplementary documentation for the advancement of cushion protection technology and the optimization of product structure.

Impact of Elexacaftor–Tezacaftor–Ivacaftor Therapy on Body Composition, Dietary Intake, Biomarkers, and Quality of Life in People with Cystic Fibrosis: A Prospective Observational Study

Background: The combination of elexacaftor–tezacaftor–ivacaftor modulators (ETI) has improved clinical outcomes for people with cystic fibrosis (pwCF). Objectives: This study aimed to evaluate changes in nutritional and morphofunctional assessments, as well as anxiety, depression symptoms, and quality of life, in pwCF after starting ETI therapy. Methods: This was a prospective observational study. We measured body composition (fat mass [FM] and fat-free mass [FFM]) using bioelectrical impedance analysis (BIA) and skinfold thickness measurements (SMs). We also assessed hand grip strength, dietary intake via surveys, blood and stool biomarkers, symptoms of anxiety and depression using the Hospital Anxiety and Depression Scale [HADS], and quality of life through the Cystic Fibrosis Questionnaire—Revised (CFQR). Results: A total of 31 pwCF were evaluated. Significant improvements were observed in respiratory function and quality of life, alongside an average weight increase of approximately 5 kg (60% FM and 40% FFM). The prevalence of malnutrition, based on BMI and the FFM index, decreased significantly, while the rate of overweight/obesity increased. Biomarker analysis indicated better nutrient absorption and reduced intestinal inflammation, as evidenced by significant changes in faecal calprotectin, nitrogen, and fat levels, as well as blood lipid and vitamin profiles. Conclusions: Despite a reduction in caloric intake, an increase in weight was observed one year after initiating ETI. This increase was attributed to gains in both FM and FFM, suggesting improved metabolic efficiency and nutrient absorption. Both SM and BIA were found to be useful assessment tools. These findings indicate the need to modify the nutritional approach, focusing on the quality rather than the quantity of intake, and aiming for an appropriate body composition (FFM) rather than solely focusing on BMI.

Experimental Research on Dynamic Mechanical Properties of High-Density Foamed Concrete.

Foamed concrete is increasingly utilized in protection engineering because it offers a high energy absorption ratio and a relatively low construction cost. To investigate the dynamic properties of foamed concrete, a series of dynamic compression tests are carried out on high-density foamed concrete with densities of 800 kg/m3, 1000 kg/m3, and 1100 kg/m3 under a strain rate range of 59.05 s-1~302.17 s-1 by using a Φ-100 mm split Hopkinson pressure bar (SHPB) device. The effects of strain rate on the stress-strain relationship, dynamic compressive strength, and dynamic increase factor of foamed concrete are discussed in detail. The results show that the dynamic mechanical characteristics of foamed concrete with different densities exhibit a significant strain rate enhancement effect. Additionally, the energy absorption characteristics of foamed concrete are investigated, demonstrating that it can effectively prevent the transmission of incident energy and that its energy absorption efficiency declines as the strain rate increases. A high-speed camera was also employed to capture the failure process of foamed concrete. The results exhibit that fracture production and development induce the failure of foamed concrete, the failure process of foamed concrete advances as the strain rate increases, and the failure mode becomes increasingly severe.