High Absorption Characteristics Research Articles

Synergistic magnetic/dielectric loss and layered structural design of Ni@carbon fiber/Ag@graphene fiber/polydimethylsiloxane composite for high-absorption EMI shielding

Simultaneously achieving excellent shielding effectiveness (SE) and high absorption rate of flexible electromagnetic interference (EMI) shielding materials has become a growing demand for the new generation of highly integrated electronic devices. This study constructed a double-layer polydimethylsiloxane (PDMS) EMI shielding composite film, with the upper layer using Ni-plated carbon fiber (Ni@CF) as the high absorption loss part and the lower layer using Ag-plated graphene fiber (Ag@GF) as the reflection attenuation part. Due to the synergistic magnetic/dielectric loss effect in the upper layer, high electrical conductivity in the lower layer, and the shielding mechanism of “absorption-reflection-reabsorption” induced by the double-layer structure, this composite film achieves efficient EMI shielding performance and high absorption characteristics in the X-band. The EMI SE values of the 2 mm thick film containing 0.03 wt% Ni@CF and 1.2 wt% Ag@GF reach 33.7 dB, while shielding effectiveness of reflection (SER) and absorption (SEA) is 0.8 dB and 32.9 dB, respectively. This result means that the composite film only reflects 17.2 % of the microwaves while shielding 99.9 % and absorbs nearly 82.7 %, exhibiting a significant absorption-dominated shielding mechanism. This flexible and efficient shielding film with a high absorption rate suits portable and wearable intelligent electronic products to reduce secondary electromagnetic pollution.

Imazalil resulted in glucolipid metabolism disturbance and abnormal m6A RNA methylation in the liver of dam and offspring mice

As a fungicide with the characteristics of high effectiveness, internal absorption and broad spectrum, imazalil is widely used to prevent and treat in fruits and vegetables. Here, pregnant C57BL/6 mice were exposed to imazalil at dietary levels of 0, 0.025‰, and 0.25‰ through drinking water during pregnancy and lactation. We then analyzed the phenotype, metabolome, and expression of related genes and proteins in the livers of mice. There was a marked decrease in the body and liver weights of male offspring mice after maternal imazalil exposure, while this effect on the dam and female offspring was slight. Metabolomics analyses revealed that imazalil significantly altered the metabolite composition of liver samples from both dams and offspring. The preliminary results of the analysis indicated that glucolipid metabolism was the pathway most significantly affected by imazalil. We performed a coabundance association analysis of metabolites with significant changes in the pathway of glycolipid metabolism, and IMZ altered the networks of both dams and offspring compared with the network in control mice, especially in male offspring. The hepatic triglyceride, non-esterified fatty acid and glucose levels were increased significantly in the dams but decreased significantly in male offspring after maternal imazalil exposure. Furthermore, the expression levels of genes associated with glycolipid metabolism and m6A RNA methylation were significantly affected by maternal intake of imazalil. Imazalil-induced glucolipid metabolism disturbance was highly correlated with m6A RNA methylation. In conclusion, maternal imazalil exposure resulted in glucolipid metabolism disturbance and abnormal m6A RNA methylation in the livers of dams and offspring mice. We expected that the information acquired in this study will provide novel evidence for understanding the effect of maternal imazalil exposure on potential health risks.

Sound Absorption Properties of An Open-Cell Ceramic with A High Occupancy Ratio for Recycling of Sediment from Taihu Lake

This paper proposes an open-cell ceramic acoustic material to combat noise pollution, which utilizes sediment from Taihu Lake as its main ingredient. The open-cell ceramic is manufactured using the gel injection molding method to achieve a high occupancy ratio. Simulation and experimental research demonstrate that the open-cell ceramics possess excellent sound absorption properties, particularly in the middle and high frequencies, with high sound absorption characteristics. The unique pore structure of the open-cell ceramics provides multifunctional and excellent mechanical properties, resulting in a lightweight, pore-designable, and broad-frequency sound absorption material that is environmentally friendly, energy-efficient, and renewable.

Determination of lekethromycin in plasma and tissues of pneumonia-infected rats by ultra-high performance liquid chromatography-tandem mass spectrometry

Lekethromycin (LKMS), a novel semi-synthetic macrolide lactone, had the characteristics of high plasma protein binding rate, fast absorption, slow elimination, and wide distribution in rat pharmacokinetics studies. A reliable analytical ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS)-based method was established by using tulathromycin and TLM (CP-60, 300) as internal standards for detection of LKMS and LKMS-HA, respectively. Samples preparation and UPLC-MS/MS conditions were optimized for complete and accurate quantification. Tissue samples were extracted with 1% formic acid in acetonitrile and purified by PCX cartridges. According to FDA and EMA guidelines for bioanalytical method, several rat characteristic tissues were selected for method validation, such as muscle, lung, spleen, liver, kidney, and intestines. The transitions m/z 402.900 > 158.300, m/z 577.372 > 158.309, m/z 404.200 > 158.200, and m/z 577.372 > 116.253 were monitored and quantified for LKMS, LKMS-HA, tulathromycin and TLM, respectively. According to the ratio with IS peak aera, the accuracy and precision of LKMS were 84.31%-112.50% with RSD 0.93%-9.79% and LKMS-HA were 84.62%-103.96% with RSD 0.73%-10.69%, and the method had been established and complied with FDA, EU, and Japanese guidelines. Finally, this method was applied to detect LKMS and LKMS-HA in plasma and tissues of pneumonia-infected rats that were intramuscularly administered and treated with LKMS intramuscular injection of 5 mg/kg BW and 10 mg/kg BW, and the characteristics of pharmacokinetics and tissue distribution were compared with normal rats.

A dual-functional hydrogel for efficient water purification: Integrating solar interfacial evaporation with fenton reaction

Solar interfacial evaporation is a potential technology to produce clean water due to its simplicity and being driven by renewable clean energy, but it still requires further development to break through the bottleneck of removing volatile organic compounds (VOCs), especially in wastewater treatment. Herein, we proposed a dual-functional hydrogel evaporator that coupled solar interfacial evaporation with Fenton reaction to simultaneously remove VOCs and non-volatile pollutants from water with low energy consumption and high efficiency. The evaporator was composed with β-FeOOH and polydopamine (PDA) on an electrospun nanofibrous hydrogel. Arising from the PDA with excellent photothermal properties, the evaporator revealed a high light absorption characteristics (∼90%) and photothermal efficiency (83.4%), which ensured a favorable evaporation rate of 1.70 kg m-2 h-1 under one solar irradiation. More importantly, benefited from the coupled Fenton reaction, the VOCs removal rate of β-FeOOH@PDA/polyvinyl alcohol nanofibrous hydrogel (β-FeOOH@PPNH) reached 95.8%, which was 6.5 times than that of sole solar interfacial evaporation (14.8%). In addition, the evaporator exhibited an outstanding non-volatile pollutant removal capability and stable removal performance for organic pollutants over a long period of operation. The prepared β-FeOOH@PPNH evaporator provides a promising idea for simultaneous removal of non-volatile pollutants and volatile pollutants performance in long-term water purification.

Cross-Scale Light Absorption Properties of Surface Bionic Microstructures for Spacecraft Stealth

To address the problem that the black coating for spacecraft optical stealth easily falls off, this study constructs a light-absorbing spacecraft surface based on a micro/nanostructure through imitating a natural light-trapping structure. In this paper, we first analyze the optical properties of a basic stealth structure with the finite difference time domain (FDTD) method and establish a mapping relationship between the light absorption rate of the basic stealth structure and its multiscale factors. Then, imitating the microstructural characteristics of the blackened parts of butterfly wings, we design a multilayered and multiscale complex stealth structure to achieve the optical stealth characteristics of low reflection and high absorption of sunlight on the surface of the spacecraft. Simulation analysis shows that the bionic microstructure can be used to change the optical properties of the metal surface to a certain wavelength band; the complex stealth structure designed based on the butterfly wing can absorb 80.18% of visible light and reduce the overall brightness of the high-orbiting spacecraft by four orders of magnitude.

MXene nanorods-based metasurface wideband absorber for infrared regime

This paper presents a wideband MXene-based metamaterial absorber made of subwavelength-sized periodic nanorods of MXene operating in the infrared regime. The top metasurface structure comprises a simple design and is made of a thin layer of MXene that features high tunability and high absorption characteristics. It is noticed that the proposed absorber shows absorption of above 80% over a wide range, from 1150 to 2500 nm. This significant absorption results due to localized surface plasmonic resonance (LSPR) of the top metasurface of periodic nanorods. The designed MXene-based optical absorber features a polarization-insensitive nature and demonstrates almost the same absorption over the wider portion of the spectrum for both transverse electric (TE) mode and transverse magnetic (TM) mode. Moreover, the proposed absorber shows a stable absorption for the obliquity incident angles up to 50°. The simulation results of the proposed absorber are verified using the Fabry-Parrot interference theory, and both results show a good agreement. The given absorber shows potential for various exciting applications, such as solar cells, sensors, and infrared imaging.

Design of embedded metamaterial solar absorber based on genetic algorithm

To effectively collect the solar energy, a metamaterial solar absorber operating in the UV to NIR wavelength range is designed, which consists of an embedded structure stacked with Ti and SiO2. The embedded structure can enhance the magnetic and electric fields to improve the absorption rate. However, the parameter space of the embedded structure is very huge to increase the optimization search time. Therefore, the absorption rate is calculated by the finite difference time domain method and the parameters of the absorber are optimized by genetic algorithm. The results show that the absorption rates of the optimized absorber are all over 95% in the 300–2500 nm and the average absorption rate is 98.7%, and the absorber is of polarization independence and the average absorption rate remains above 95% at an oblique incidence angle of 60°. By analyzing the electromagnetic field distribution of the absorber at the resonance wavelength, it can be concluded that the high absorption characteristics in the wideband are mainly achieved by the combined effects of local surface plasmon resonance, electric dipole resonance, propagating surface plasmon resonance and Fabry-Perot cavity resonance. Perfect absorber in the solar spectral range have significant value in fields such as solar energy harvesting and information detection.

Structure design of multi-layered ABS/CNTs composite foams for EMI shielding application with low reflection and high absorption characteristics

The low-reflection and high-absorption features for electromagnetic (EM) waves are the key and significant requirements for fabricating efficient EM interference (EMI) shielding polymer-based composite foams. Herein, single-layered acrylonitrile–butadienestyrene (ABS)/carbon nanotubes (CNTs) foams with three representative pore structures (nano-pores, micro-pores and regular pores) were produced via supercritical CO2 foaming technology. Subsequently, they were stacked together to obtain multi-layered ABS/CNTs foams through structural design for achieving the high absorption and low reflection characteristics described above. Among all the unfoamed and foamed ABS/CNTs specimens, nano-porous ABS/CNTs foams could reach the maximum electrical conductivity of 3.7 S/m. The multi-layered ABS/CNTs foam with positive pore gradient structure exhibited the best EM wave absorption coefficient of 0.90. The sandwich structure formed in ABS/CNTs foam by sandwiching a middle layer of regular porous foam between nano-porous foam and micro-porous foam increased EM wave absorption properties, owing to the generation of constructive interference. This work provides new insight and methodology for the design and fabrication of multi-layered EMI shielding polymer-based composite foams with low reflection and high absorption.

A review on lignin based nanocomposites: Fabrication, characterization and application

Polymer Composite material is made of two or more constituent materials that, when combined, produce a material with properties that are distinct from those of the individual constituents. The fabrication of polymer nanocomposites especially lignin-based nanocomposites are growing prospective research interest, thanks to various advancements made possible by the combination of a polymeric matrix with, in most cases, an inorganic nonmaterial. The advancement and modification of lignin-based nanocomposites is a step towards the replacement of conventional plastics (traditional polymer). Polymer composites have been produced or formed specifically for a variety of applications that are employed in a specific location for a specific purpose. Lignin is a highly heterogeneous polymer that is found naturally in plants that account for up to 15–35% of woody biomass made up of several precursors. Lignols that crosslink in a variety of ways with antioxidant property, high thermal stability, biodegradability, and UV absorption characteristics. Despite the fact that lignin is the most prevalent phenolic component in nature, and a small percentage of lignin removed by industrial processing which gets turned into dispersants and fillers has the potential to enhance various properties like mechanical, thermal, thermo-chemical, anticorrosive, flame retardant and many more of the polymer composite which is beneficial for our society as well our environment.

Molecular docking simulation, drug pharmacokinetics and synthesis of carbon nanodots from phytochemicals against isoenzymes of cancer

We report drug likeliness, pharmacokinetics, and molecular docking studies of nineteen potential bioactive compounds of Cuminum cyminum and their synthesis and characterization of carbon nanodots (CNDs) using plant aqueous extract at different high temperatures and different concentrations of the extract. Our results of drug likeliness showed compounds followed Lipinski’s, Veber’s, and Egan’s rule, whereas the pharmacokinetics study establishes high absorption characteristics of these compounds in the gastrointestinal tract and can cross the blood–brain barrier. A molecular docking study shows alpha-pinene (-26.45 kcal/mol), terpinen-4-ol (-28.26 kcal/mol), transpinocarveol (-26.47 kcal/mol) and cis-anethole (-26.26 kcal/mol) releases high binding energy and hence binds strongly with human topoisomerase I DNA (HTIDNA). CNDs shows a TEM size of around 50 nm and are found to have an optimum concentration of 5 mg/ml at 200°Cduring the synthesis of CNDs.

Preparation and Evaluation of Bacterial Nanocellulose/Hyaluronic Acid Composite Artificial Cornea for Application of Corneal Transplantation.

The treatment for corneal damage requires donor corneal transplantation, but there is a serious scarcity of donor corneas worldwide. In this study, we aimed to design a new artificial cornea with good cytocompatibility, excellent optical properties and suture resistance, and great moisturizing properties. A new bacterial nanocellulose (BNC) membrane with anisotropic mechanical properties and high light transmission was produced in a horizontal rotary drum reactor. However, as a potential material for artificial keratoplasty, the transparency and mechanical properties of the new BNC membrane were not satisfactory. Thus, hyaluronic acid (HA) was introduced in the BNC to synthesize the BNC/HA composite membrane by using 1,4-butanediol diglycidyl ether (BDDE) as the chemical cross-linking agent. The micro-morphology, light transmittance, mechanical properties, water content, moisture retention ability, and cytocompatibility of the composite membranes were further evaluated. HA was fixed in the BNC network by the ether bond, and the composite membrane was found to have excellent light transmittance (up to 95.96%). The composite membrane showed excellent mechanical properties, for instance, its tensile strength exceeded the human normal intraocular pressure (IOP) (1.33-2.80 kPa), the maximum burst pressure was about 130 kPa, 46-97 times that of the normal IOP, and its suture force was close to that of the human amniotic membrane (0.1 N). Based on the three-dimensional network scaffold of BNC and the high water absorption characteristics of HA, the artificial cornea had high water content and high moisture retention ability. The rabbit corneal stromal cells cultured in vitro showed that the artificial cornea substitute had excellent cytocompatibility. BDDE is the most frequently used cross-linker in most HA products in the current cosmetic medicine industry owing to its long-term safety records for over 15 years. Therefore, the BNC/HA composite hydrogel cross-linked with BDDE has great potential in artificial keratoplasty or ocular surface repair.

Energy Absorption Characteristics of Bio-Inspired Honeycomb Column Thin-Walled Structure under Low Strain Rate Uniaxial Compression Loading

The beetle’s elytra have the characteristics of light weight and high energy absorption (EA). In this paper, based on the internal structure of beetle elytra, two bio-inspired honeycomb column thin-walled structures (BHTS) I and II were fabricated by selective laser melting (SLM) technology in additive manufacturing (AM) in order to understand the possible influence of strain rate effect (SRE) on the BHTS under low speed uniaxial compression loading. The influence of three different SREs (0.001 s−1, 0.01 s−1 and 0.1 s−1) on the EA of BHTSs specimens during loading was discussed by means of out-of-plane uniaxial compression tests verified with numerical simulations. The experimental results show that SRE has a significant effect on the EA of BHTSs in low speed out-of-plane uniaxial compression tests: SRE can significantly increase the initial peak crushing force (PCF) and specific energy absorption (SEA) of all types of BHTS specimens. The average increase in PCF/SEA under SRE loading of 0.1 s−1 is 12.70%/9.79% and 17.63 %/11.60%, respectively, compared with 0.001 s−1 and 0.01 s−1. These research methods reduce the use of materials and improve the utilization rate of materials, which can provide important assistance for the design, manufacture and modeling of AM-based materials.

Enhanced sound absorption characteristic of aluminum-polyurethane interpenetrating phase composite foams

Open-cell aluminum foams with large pore size (4.41 mm), large pore opening size (1.45 mm) and low thickness (10 mm) exhibit unsatisfied sound absorption characteristic in the low-middle frequency range. To improve this characteristic, novel aluminum-polyurethane interpenetrating phase composite foams (Al/PU IPC foams) were successfully prepared by producing polyurethane foams in the internal cavities of open-cell aluminum foams. The sound absorption coefficient of the Al/PU IPC foams is above 0.3 in the frequency range of 670–1600 Hz and shows a maximum value of 0.67 at about 1150 Hz, which is ∼ 10 times higher than that of the open-cell Al foams with equal thickness, attributing to the small pore size, fine pore opening size and high sound absorption characteristics of internal polyurethane foams.

Elucidation the effectiveness of acridine orange as light-harvesting layer for photosensing applications: Structural, spectroscopic and electrical investigations

In this research, acridine orange, AO, bio-photosensitive thin films are prepared using vacuum thermal evaporation technique for optoelectronic applications. First, the crystal structure of the deposited films compared to powder is investigated using the XRD technique. Next, the surface morphology of the deposited AO thin film is characterized using the FESEM technique giving rise to a uniform, homogeneous, and granular polycrystalline film. The amplitude and spatial roughness parameters of the film are estimated. Furthermore, the optical properties of the deposited AO thin film are spectrophotometrically characterized in the range from UV to NIR. The recorded absorbance, transmittance, and reflectance showed high UV and visible absorption characteristics with a direct energy gap of ∼2.238 eV. The optical constants, including refractive index and extinction coefficient, are found, and the dispersion behavior is analyzed using the one-oscillator model for estimating the oscillator and dispersion energies. The dielectric function and dielectric relaxation time of AO thin film are interpreted in detail. In addition, an organic/inorganic heterogeneous junction based on Ag/AO/p-Si/Al is fabricated and electrically evaluated using the current-voltage relation. The fabricated heterojunction shows a rectification behavior of ideality factor, barrier height, and rectification ratio ∼2.09, 0.707 eV, and 176, respectively. The charges dynamics mechanism in terms of band diagram and the density of interface states profile are analyzed. Eventually, the photoresponse of the engineered heterojunction is evaluated under the illumination of intensities that varies from 20 mW/cm2 to 100 mW/cm2. The fabricated photosensor showed a high stable performance with responsivity, specific detectivity, linear dynamic range, and ON/OFF ratio of about 68.4 mA/W, 1.11 × 1010 Jones, 69.3 dB, and 108.4, respectively. The photoresponse performance of the present device is considered more efficient and stable than many other organic/inorganic photosensors.

Graphite-oxide hybrid multi-degree of freedom resonator metamaterial for broadband sound absorption

Low frequency broadband sound absorption for thin structures is still a great challenge. A new concept of a stackable hybrid resonator metamaterial is proposed which exhibits super broadband low-frequency sound absorption. The proposed metamaterial is based on micrometric scale thickness Graphene Oxide (GO) embedded in a stacked structure or used as external skin in a designed honeycomb (HC) structure. The stackable nature of the proposed structure allows the GO-HC cores to be embedded within micro-perforated panels (MPP) providing enhanced stiffness/strength to the structure and high absorption characteristics. We demonstrate how the exploitation of the GO elastic and mass properties result in multiple hybrid structural–acoustic resonances. These resonances are tailored to occur in a frequency range of interest by the theoretical calculation of the sound absorption coefficient. The theoretical model combines the mutual interaction between the structural dynamic of the GO foil and acoustic higher modes of the HC core cell as well as stacked MPP-HC/GO-HC cores. The result is a multi-degree of freedom hybrid resonator which provides subwavelength scale broadband sound absorption in low frequency range between 300 and 2500 Hz.

Femtosecond Pulsed Fiber Laser by an Optical Device Based on NaOH-LPE Prepared WSe2 Saturable Absorber.

We report on all-optical devices prepared from WSe2 combined with drawn tapered fibers as saturable absorbers to achieve ultrashort pulse output. The saturable absorber with a high damage threshold and high saturable absorption characteristics is prepared for application in erbium-doped fiber lasers by the liquid phase exfoliation method for WSe2, and the all-optical device exhibited strong saturable absorption characteristics with a modulation depth of 15% and a saturation intensity of 100.58 W. The net dispersion of the erbium-doped fiber laser cavity is ~−0.1 ps2, and a femtosecond pulse output with a bandwidth of 11.4 nm, a pulse width of 390 fs, and a single-pulse capability of 42 pJ is obtained. Results indicate that the proposed WSe2 saturable absorbers are efficient, photonic devices to realize stable fiber lasers. The results demonstrate that the WSe2 saturable absorber is an effective photonic device for realizing stable fiber lasers, which have a certain significance for the development of potential photonic devices.

Study of Composite Bricks from Sawdust and Cement

Abstract: Many timber producing countries generate more than 2 million m3 of sawdust annually. In developing countries, sawdust is often disposed of by open dumping, open burning, or dumping in landfills. The majority of wood sawdust wastes is accumulated from the countries all over the world and causes certain serious environmental problems and health hazards. This poses huge environmental challenges related to air pollution, greenhouse gas emission and destruction of plant and aquatic life. Finding from this experiment that sawdust can be used to make sawdust construction composites with good water absorption and strength characteristics. In this experiment concludes that partially replacing 10%, 20% and 30% of sawdust with sand and cement. Sawdust composites are also attractive for their low thermal conductivity, high sound absorption and good sound insulation characteristics. These findings indicate that increased utilization of sawdust composites in construction will mitigate against potential sawdust environmental pollution, conserve energy and reduce disposal costs. It shows a potential to be used for walls, wooden board substitute, economically alternative to the concrete blocks, ceiling panels, sound barrier panels, etc. Keywords: Sawdust, Sawdust Composites, Thermal Conductivity, Sound Absorption, Sound Insulation etc.

Ultra-broadband terahertz absorber based on double truncated pyramid structure

Terahertz (THz) absorbers have attracted considerable attention due to their potential applications. However, the limited bandwidth of THz absorbers limits their further applications. To achieve ultra-broadband and high absorption characteristics in the THz band, a double truncated pyramid unit structure combining the hybrid planar structure and the few-layers vertical structure is proposed. The double truncated pyramid structure composed of five metal layers and five graphene layers has the advantages of ultra-broadband, tunability, polarization-insensitive and wide-angle absorption. The simulation results show that the absorption coefficient of the absorber is over 0.9 from 1.49 THz to 12.72 THz. The double truncated structure provides perfect ultra-broadband absorption, which can be attributed to the localized surface plasmon and surface plasmon. The mechanism of resonance can be further explained by surface current distribution. Meanwhile, the absorption mechanism of the absorber can also be explained by the impedance matching theory. The proposed THz absorbers have potential applications in sensing, stealth and other multispectral devices.

Combining Perovskites and Quantum Dots: Synthesis, Characterization, and Applications in Solar Cells, LEDs, and Photodetectors

AbstractMetal halide perovskites having high defect tolerance, high absorption characteristics, and high carrier mobility demonstrate great promise as potential light harvesters in photovoltaics and optoelectronics and have experienced an unprecedented development since their occurrence in 2009. Semiconductor quantum dots (QDs), on the other hand, have also been proved to be very flexible toward shape, dimension, bandgap, and optical properties for constructing optoelectronic devices. Of late, a strategic combination of both materials has demonstrated extraordinary promise in photovoltaic applications and optoelectronic devices. Combining QDs and perovskites has proved to be quite an effective strategy toward the formation of pinhole‐free and more stable perovskite crystals along with tunability of other properties. To boost this exciting research field, it is imperative to summarize the work done so far in recent years to provide an intriguing insight. This review is a critical account of the advanced strategy toward combining these two fascinating materials, including their different synthetic approaches regarding heteroepitaxial growth of perovskite crystals on QDs, carrier dynamics at the interface and potential application in the field of solar cells, light emitting diodes, and photodetectors.