Good Absorption Research Articles

Vibration Control of Corrugated Steel Web Box Girder Bridge with Friction Pendulum Isolation

In order to investigate the feasibility and applicability of friction pendulum bearings for vibration control of large-span space beam-arch bridges with corrugated steel web box girders, taking the Huian Yellow River Bridge in Guide County, Qinghai Province, China, as an example. A three-dimensional calculation model of the friction pendulum isolation space beam-arch composite bridge with a corrugated steel web was established by MIDAS, the modal analysis was carried out, and the damping effect of the friction pendulum isolation bridge was investigated using the response spectrum and the time history analysis methods; the influence of the design parameters of the friction pendulum isolation on the reduction effect was further analyzed. The results show that the friction pendulum isolation improves the stress conditions of both the girder and the pier and reduces the displacement and acceleration of the pier top, as well as reduces the acceleration of the girder, and the damping ratio is more than 50%. The optimal dynamic coefficient of friction and the radius of curvature for the corrugated steel web composite bridge are 0.04 and 3.0 m, respectively. Friction pendulum isolation has a good seismic absorption effect and provides an effective way for the seismic control of the corrugated steel web composite bridge. Doi: 10.28991/CEJ-2024-010-10-01 Full Text: PDF

The synthesis and application of MRI-fluorescence dual mode materials with absorption ability on quantitative analysis of malachite green

The histidine/Mn3O4/CdTe quantum dots (HMQ) composites with good magnetic resonance/fluorescent imaging and absorbance performance have been prepared based on biomimetic mineralization method, on which the peptide served as a carrier to guide the formation of Mn3O4 and CdTe quantum dots. The fluorescence of HMQ could be quenched by malachite green (MG), whereas the magnetic resonance signal (T1-MRI) was enhanced. Also, there is a linear correlation between the concentrations of MG added and the decreasing fluorescence intensity of HMQ (F0/F), the detection range is 0.06851–1.096 nmol l−1, and the LOD is 0.02750 nmol l−1. The corresponding T1WI detection range is 13.7–95.9 nmol l−1, and the LOD is 7.617 nmol l−1. Furthermore, the fluorescence quenching spectra of the HMQ adopted by MG have been analyzed, of which the data fit well with the law of pseudo-second-order kinetics, indicating that the prepared HMQ has good absorption properties. Therefore, HMQ could be used as an MRI/fluorescent dual sensor for the detection of MG.

Self-healing, adhesive, antibacterial, and biocompatible hydrogel dressings using sialic acid substituted chitosan and oxidized pullulan with incorporation of epigallocatechin gallate

The development of innovative therapeutic strategies is highly desired for wound regeneration. In this study, sialic acid substituted chitosan (CS-SA) was reacted with oxidized pullulan (OPL) via Schiff base links to obtain functional CS-SA/OPL hydrogels, into which the polyphenol epigallocatechin gallate (EGCG) was in situ incorporated. The prepared hydrogels exhibited interconnected porous structure and good water absorption ability (over 37 g/g). Furthermore, the CS-SA/OPL hydrogels performed excellent self-healing and adhesive properties. With the incorporation of EGCG, the antibacterial effects against E. coli and S. aureus, as well as antioxidative activity, were significantly improved. In addition, in vitro L-929 cell experiments confirmed that cell viability and cell immigration could be significantly improved with the incorporation of EGCG in CS-SA/OPL hydrogels. Based on the above results, hydrogels possess a promising potential as wound dressings in wound healing applications.

Lightweight dielectric-magnetic synergistic necklace-shaped Co@NCP/carbon nanofiber composites for enhanced electromagnetic wave absorption

In order to solve the problem of impedance mismatch of carbon fiber absorbing materials, it is crucial to create a carbon-based absorbing material with a special structure, synergistic magnetic and dielectric properties. In this paper, necklace-shaped Co@N-doped carbon polyhedron/carbon nanofiber (Co@NCP/CNF) composites with synergistic magnetic and dielectric properties are successfully fabricated by electrospinning. Compared with Co@NCP and CNF, the optimal minimum reflection loss of Co@NCP/CNF composite is −66.14 dB at 2.89 mm and the maximum effective absorption bandwidth is 6.24 GHz (11.76–18.00 GHz) at 2.25 mm at a low filler load of 10 wt%. The necklace-like structure, the coupling effect of dielectric and magnetic materials and the heterogeneous interface form multiple polarizations, conductive losses and multiple loss mechanisms to optimize impedance matching and attenuation performance, which is conducive to excellent absorption performance. More importantly, the radar cross section (RCS) reduction is as high as 24.02 dB m2, which has proven to have a good absorption effect in actual application environments. This work combines the advantages of Co@NCP and CNF very well, which provides guidance for designing EM waves nanocomposite fiber absorbers with lightweight and strong absorbing properties.

Research and Application Status of Soft Steel Dampers

Soft steel dampers have stable hysteresis characteristics and can effectively dissipate energy under repeated loads, providing good shock absorption effects for structures. It can be used for both seismic design of new buildings and seismic reinforcement of existing buildings. Suitable for various structural forms of buildings, including concrete structures, steel structures, and heavy-duty wooden structures. It is also applied in bridge structures, which can effectively reduce the vibration response of bridges under earthquake, wind vibration, etc., and improve the seismic performance and safety of bridges. Countries with rapid development in the application of structural control technology, such as the United States, Japan, Canada, New Zealand, and Mexico, are the main ones. Italy, France, Russia, Singapore, and other countries are also actively applying it in practical engineering. More than a hundred buildings abroad have adopted soft steel dampers.

Mechanical behaviors of composite auxetic structures under quasi-static compression and dynamic impact

This paper presents a low-velocity impact study on two types of structures, namely (1) planar multi-cellular auxetic structures (AUS) composed of multiple re-entrant cell structures made of unidirectional carbon fiber reinforced composite (CFRP) laminate, and (2) sandwich CFRP-AUS structures (Al/CFRP-AUS), whereby the CFRP-AUS was sandwiched by aluminium plates. The experimental results reveal the mechanical behaviors of CFRP-AUS under quasi-static compression and drop hammer impact loading, and the mechanical behavior of Al/CFRP-AUS under drop impact loading. The energy absorption of the CFRP-AUS associated with quasi-static compression is greater than that associated with drop hammer impact, which is consistent with the observed differences in failure modes. The impact energy absorption capacity of the Al/CFRP-AUS is slightly higher than that of the CFRP-AUS due to the interaction between the plates and the AUS. The corresponding finite element analysis was performed and the drop hammer impact of the multi-layered CFRP-AUS was predicted. In conclusion, the CFRP-AUS structures have good energy absorption capacity during impact loading, and the known complex mechanical behaviors of deformation, failure and contact can provide guidance for the design of energy absorption box and bumper in engineering application.

Fe-MOF derived Fe3O4/C-based hydrogel for efficient solar-driven photothermal evaporation

Solar-driven interfacial photothermal evaporation (SIPE) has been considered as a green and sustainable technology for obtaining fresh water, and the exploring efficient photothermal materials is crucial. Nanocomposite derived from metal-organic framework exhibits high light absorption properties and excellent chemical stability, making it an ideal candidate in the SIPE. Herein, Fe3O4/C nanocomposite was obtained using MIL-101 (Fe) as a precursor, and Fe3O4/C-based porous hydrogel (Fe3O4/C-PH) was subsequently prepared through chemical crosslinking foaming polymerization. The obtained Fe3O4/C-PH exhibited an evaporation rate of 3.33 kg m−2 h−1 under one sun intensity. Fe3O4/C-PH demonstrated outstanding desalination and salting out resistance when treating real seawater. Moreover, it could remove over 99 % of dyes from wastewater. The photothermal mechanisms are molecular thermal vibration of C component and semiconductor relaxation of Fe3O4. Meanwhile, the hydrophilic and porous skeleton structure of the hydrogel ensure Fe3O4/C-PH to transport water rapidly and exhibit good light absorption properties. This research broadens the candidate of photothermal materials for applications in SIPE, and also provides new avenues for desalination and wastewater purification.

Polypod Carboxylic Acid-Rare Earth Complex with High Cyclic Stability for Nitrobenzene Compound Detection.

The 5',5''-bis(4-carboxyphenyl)-[1,1':3',1'':3'',1'''-quaterphenyl]-4,4'''-dicarboxylic (H4L1) ligand has a large conjugated rigid planar structure and good absorption of ultraviolet radiation, which can provide effective "antenna effect". However, rare earth complexes using H4L1 as the sole ligand have not been reported. In this paper, rare earth Eu was combined with H4L1 ligand to produce organic rare earth composite L1-Eu by solvothermal synthesis method. It was found through fluorescence spectroscopy that the emission of L1-Eu complex has a linear response to nitrobenzene compounds. The L1-Eu composite material has a low detection limit for nitrobenzene compounds, with detection limits of 0.910, 8.401, 24.510, and 8.171 µM for nitrobenzene, o-nitrophenol, m-nitrophenol, and p-nitrophenol, respectively. Further more the L1-Eu complex can sensitively respond to nitrobenzene compounds while resisting interference from common metal ions and organic solvents. In particular, L1-Eu composite material has good stability and recyclability. Therefore, L1-Eu composite material can serve as a fluorescent probe for specific detection of nitrobenzene compounds. We believe that the L1-Eu complex provides a new method for fluorescence detection of nitrobenzene compounds.

Synthesis and properties of the natural ultraviolet absorber gadusol in Komagataella phaffii

Gadusol, an efficient natural ultraviolet (UV) absorbing substance with antioxidant capacity, is ubiquitous in aquatic organisms such as microorganisms, algae, and fish eggs. In order to address issues such as its low natural extraction yield and environmental unfriendliness, we introduced the gadusol synthesis pathway from zebrafish into Komagataella phaffii and successfully constructed the recombinant strain capable of synthesizing gadusol. The xylose assimilation genes derived from Scheffersomyces stipitis were further introduced into the recombinant strain to increase the content of the key substrate sedoheptulose 7-phosphate (S7P). The results showed that the utilization of xylose was an effective strategy to increase the yield of gadusol. In the medium with only xylose as the substrate, the yield of gadusol reached 141.8 mg/L (32.3 mg/g dry cell weight, DCW), which was about 46 times of that in the medium with only glucose as the substrate. The product showed obvious absorption in the range of 275-305 nm, with the maximum absorption at 290 nm. Moreover, the product demonstrated antioxidant capacity. After reaction for 5 h, the ferric ion reducing antioxidant power (FRAP), 2, 2'-azino- bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging rates changed by 90.83%, 25.50%, and 131.80%, respectively, which suggested that the product may be used as a long-acting antioxidant. This study demonstrated the great potential of K. phaffii as a chassis for the biosynthesis of natural UV absorbers. The biosynthesized gadusol has good UV absorption and antioxidant properties, which provides a theoretical basis for the industrial production and application of gadusol.

Acute Toxicity Assessment of Cream Ethanolic Extract of Vitex pinnata Bark from Central Kalimantan.

Vitex pinnata bark has the ability to scavenge free radicals and has antimicrobial activity, thus accelerating wound healing. The formulation of V. pinnata bark preparations has good organoleptic properties, homogenity, pH, dispersion, and absorption. We studied the acute toxicity of V. pinnata skin cream in Wistar rats according to OECD guidelines 402. Seven nulliparous, non-pregnant female Wistar rats were exposed 2000 mg/kg of body weight. There were no signs of toxicity in any behavioral, necropsy dan histopathological changes. The Globally Harmonized System classified V. pinnata cream extract as category 5 (unclassified) with LD50 more than two thousand mg/kg.

Isolation, Characterization, Moisturization and Anti-HepG2 Cell Activities of a Novel Polysaccharide from Cyanobacterium aponinum.

Polysaccharides from cyanobacteria are extensively reported for their complex structures, good biocompatibility, and diverse bioactivities, but only a few cyanobacterial species have been exploited for the biotechnological production of polysaccharides. According to our previous study, the newly isolated marine cyanobacterium Cyanobacterium aponinum SCSIO-45682 was a good candidate for polysaccharide production. This work provided a systematic study of the extraction optimization, isolation, structural characterization, and bioactivity evaluation of polysaccharides from C. aponinum SCSIO-45682. Results showed that the crude polysaccharide yield of C. aponinum reached 17.02% by hot water extraction. The crude polysaccharides showed a porous and fibrous structure, as well as good moisture absorption and retention capacities comparable to that of sodium alginate. A homogeneous polysaccharide (Cyanobacterium aponinum polysaccharide, CAP) was obtained after cellulose DEAE-52 column and Sephadex G-100 column purification. CAP possessed a high molecular weight of 4596.64 kDa. It was mainly composed of fucose, galactose, and galacturonic acid, with a molar ratio of 15.27:11.39:8.64. The uronic acid content and sulfate content of CAP was 12.96% and 18.06%, respectively. Furthermore, CAP showed an in vitro growth inhibition effect on human hepatocellular carcinoma (HepG2) cells. The above results indicated the potential of polysaccharides from the marine cyanobacterium C. aponinum SCSIO-45682 as a moisturizer and anticancer addictive applied in cosmetical and pharmaceutical industries.

Interfacial solar‐driven steam and electricity co‐generation using Hydrangea‐like graphene by salt‐assisted carbonization of waste polylactic acid

AbstractThe interfacial solar steam generation and water evaporation–driven power generation are regarded as promising strategies to address energy crisis. However, it remains challenging to construct low‐cost evaporators for freshwater and electricity co‐generation. Herein, we report a salt‐assisted carbonization strategy of waste polylactic acid to prepare Hydrangea flower–like graphene and build a bi‐functional graphene‐based evaporator. The evaporator presents merits of good sunlight absorption, photo‐to‐thermal conversion property, water transport, good thermal management capability, and negatively charged pores for the continuous diffusion of ions. Hence, it achieves the evaporation rate of 3.0 kg m−2 h−1 and output voltage of 0.425 V, surpassing many advanced evaporators/generators. Molecular dynamics simulation result proves that more Na+ ions are attracted by functional groups, especially –COOH/C–OH, to promote Na+ selectivity in nanochannels. This work offers new opportunities to construct multifunctional evaporators for freshwater and electricity co‐generation.

In-situ construction of novel Sb2(S,Se)3/CdSe S-scheme heterojunction with enhanced photoelectrochemical performance

Abstract Antimony selenosulfide (Sb2(S,Se)3) was considered to have great potential for photoelectrochemical (PEC) water splitting applications due to its excellent chemical stability, good light absorption, abundant reserves and non-toxicity. However, Sb2(S,Se)3 faces some limitations in the field of PEC, such as the serious recombination problem of photogenerated carriers. Therefore effectively restraining its deep-level defects is the crucial for enhancing its photoelectrochemical properties. In this paper, We successfully fabricated Sb2(S,Se)3/CdSe S-scheme heterojunction via one-step hydrothermal method, which improves its solar absorption capacity, facilitates efficient carrier separation. And, Sb2(S,Se)3/CdSe S-scheme heterojunction can suppress the adverse effects of deep-level defects on the PEC performance of Sb2(S,Se)3. Under simulated solar irradiation, the light current density can reach 4.02 mA cm2 (33.5 times that of monomeric Sb2(S,Se)3) at 1.23 VRHE, accompanied by low initial voltage and extremely high surface charge injection efficiency. This study is of great significance for the application of Sb2(S,Se)3 in the PEC field.

Large-energy operation of an Er-doped fiber laser with ZrGeTe4 saturable absorber

ZrGeTe4 as a layered semiconductor material with good stability and optoelectronic properties, and excellent saturable absorption characteristics, but its application in fiber lasers is still insufficient. In order to explore its application in fiber lasers, we prepared ZrGeTe4-PVA thin film by liquid phase exfoliation and performed a series of characterizations. A modulation depth of 13.15 %, a non-saturated loss of 6.4 %, and a saturation intensity of 5.5 MW/cm2 were obtained. Then used the ZrGeTe4-PVA thin film as the saturable absorber (SA) in an Er-doped fiber laser (EDFL), the large-energy operation could be realized. In the case of a cavity length of 234 m, when the pump power was increased to 1229 mW, a maximum single pulse energy of about 32.72 nJ was achieved, with a repetition frequency of 859 kHz. To the best of our knowledge, this is the highest single-pulse energy achieved in an EDFL based on ZrGeTe4-SA. This experiment shows that the ZrGeTe4 is a promising two-dimensional (2D) material with good nonlinear absorption properties, proving that it is a promising pulse modulation of SA and laying a foundation for its subsequent study in fiber lasers.

Research on a Honeycomb Structure for Pyroshock Isolation at the Spacecraft–Rocket Interface

Honeycomb is a splendid kind of structure for aerospace engineering with the advantages of light weight, good shock absorption, and good structural stability. This article aims to provide methods to isolate Pyroshocks based on a honeycomb structure and guarantee the safety of such equipment against a high-frequency shock response. According to stress wave theory, an equation for stress wave transmittance of the honeycomb structure is derived considering the effect of cell wall length and thickness, where desirable honeycomb parameters are obtained. The complexity of the transfer path of the honeycomb structure is exploited to build the spacecraft–rocket interface, which could increase the impedance of the stress wave dramatically. Both finite element analysis and experiments are carried out to validate the shock isolation strategies. The influence of parameters, such as cell wall length and the thickness of the stainless-steel honeycomb, on the isolation performance is analyzed. It is revealed that the honeycomb structure has a significant effect on Pyroshock isolation performance when the wall length of the honeycomb cell is 8 mm and the thickness of the cell is 0.1 mm.

Comparative characterizations of plant and mineral dye as potential photosensitizer in Dye-Sensitized Solar Cell

The advent of dye-sensitized solar cells (DSSC) has expansively seen more studies as an alternative to silicon-based and thin-film solar cells due to their simple structure and relatively low production cost. In dye-sensitized solar cells, the dye is one of the major components for high power conversion efficiencies. The extracted dyes were characterized by powder x-ray diffraction, x-ray fluorescence, Scanning electron microscopy, UV-visible spectroscopy, and Gas Chromatography-Mass spectrometry analysis. The structure of the mineral dye contains constituents that enhance better absorption of solar radiation for use in a Dye-Sensitized Solar Cell (DSSC). The calcium and iron content of the mineral dye studied as revealed by the mineralogical analysis done using the powder x-ray diffraction (XRD) and the x-ray fluorescence (XRF) suggest this. These metals serve as bounding complexes to other organic components in the dye, like in the case of Ruthenium complexes dye for efficient absorption of solar radiation, especially in the visible light region. The functional groups present in the dye also confirm what favors good absorption of solar radiation for DSSC application. The Organic chemical compositions present in the mineral dye which were obtained by the Gas Chromatography-Mass spectrometry analysis also confirm the functional groups of carbonyl, Amine, and hydroxyl revealed by FTIR, which were responsible for solar radiation absorption. There are strong absorption narrow bands in the visible region with peaks at around 424 nm (2.903 a.u) and 486 nm (2.973 a.u). Optical band gaps of 1.66 eV and 2.27 eV for the mineral dye and plant dye respectively, were obtained. The properties of the dyes studied give potential substitutes to the relatively expensive ruthenium-based dyes for use in DSSC fabrication.

Prediction and investigation of water repeated absorption and release properties of superabsorbent polymers during the dry-wet cycles in different solutions

Superabsorbent polymers (SAP) with a three-dimensional cross-linked network structure are used in the concrete field due to their good water absorption and water retention properties. The changes of its repeated water absorption and release properties have an important impact on crack healing, but there is still a lack of relevant research. This study mainly uses the tea-bag method to explore the repeated water absorption and release behavior of sodium polyacrylate and polyacrylic acid-acrylamide copolymers in deionized water, cement filtrate, and saturated calcium hydroxide solution. The quantitative analysis of the change in the peak area of the water-absorbing functional group was performed by fourier transform infrared spectroscopy. The morphology and elements of SAP under different dry-wet cycles were analyzed by scanning electron microscope-energy spectrum analysis. The repeated swelling behavior of SAP was predicted using the classical models. The results showed that the repeated water absorption performance of SAP gradually decreased with the increase of the number of wet-dry cycles. The slope of the curve for the second-order equation gradually increases, and the peak area corresponding to the carboxyl functional group also gradually increases. And the rate and amount of water release gradually increase. For sodium polyacrylate, with the increase in the number of wet-dry- cycles, the increase in the content of calcium, magnesium, and aluminum elements is accompanied by a significant decrease in the content of sodium elements. In contrast, the calcium content on the surface of polyacrylic acid-acrylamide copolymer increased, but the sodium content only slightly decreased.

Semaglutide functional electrospinning nanofiber membrane rescues apoptosis and promotes diabetic wound healing

The healing of diabetic wounds is a difficult problem due to decreased proliferation, and migration of epidermal and endothelial cells. Here we reported semaglutide-loaded nanofiber membrane to promote diabetic wound healing through suppressing reactive oxygen species production and accelerating angiogenesis in a diabetic rat model. The fiber membrane was prepared by an electrostatic spinning technique. The fiber membrane consisted of thermalplastic polyurethane elastomer, polyvinyl butyral ester, zein and semaglutide (SMGT). The fiber membrane had a uniformly distributed diameter, suitable water vapor transmission rate, good water absorption and retention properties. In vivo data determined that the SMGT-loaded nanofiber membrane was able to promote normal skin pathological structure formation in regenerated tissue. In vitro experiments displayed that SMGT might facilitate HG-induced endothelial cell dysfunction by inhibiting ROS production. The present study provided a theoretical basis for the extensive application of SMGT in the treatment of diabetic ulcers and other wounds.

Achieving efficient electromagnetic absorption in multifunctional carbon nanotube aerogels by manipulating radialized network structure

The rapid advancements in communication technology have greatly propelled the widespread applications of artificial intelligence (AI). While AI technology facilitates society, it also brings the unavoidable electromagnetic hazards and the issue of disposal of electronic plastic wastes. So, utilizing electronic plastic wastes to constructing carbon-based electromagnetic wave (EMW) absorption materials, are highly promising. However, how to use CNTs from plastic wastes to build good EMW absorption performance aerogels is a critical challenge. In this work, highly porous and well-interconnected network aerogels constructed by radialized CNT arrays are rationally designed under the guidance of grave-to-cradle strategy, exhibiting altered impedance matching and multiple EMW attenuation methods. Theoretical calculations suggest that a well-designed heterojunction interface structure can enhance the conductivity and interface polarization of CNTAs. The CNT aerogels (CNTAs) realize broad absorption bandwidth covering 8.48 GHz with a minimum reflection loss of −59.5 dB. Moreover, the radialized arrays network of CNTAs also endows it with electromagnetic protection, thermal management, self-cleaning, and air purification functions. These inspiring achievements of multifunctional CNTA-2 provides new help for the safe and stable promotion of the AI era.

Sustainable design and synthesis of high-performance lignin-based sunscreen ingredients

The active ingredients most commonly employed in sunscreens are compounds containing one or two aromatic rings. Lignin is the most abundant renewable aromatic polymer that has the potential to yield low molecular weight aromatic chemicals when strategically depolymerized. Here, the UV absorbance of a series of monomeric and dimeric lignin model compounds (LMCs) were studied. Specifically, vanillin and ferulic acid demonstrated good absorption in the UVB (280–320 nm) range, while the 5–5 dimer showed efficient absorption in the UVA (320–400 nm) range. Based on this, vanillin, ferulic acid and 5–5 dimer were mixed in pairs and dispersed in the oily isoeugenol to prepare LMC hybrid dispersions. Subsequently, demethylated lignin (DL) was synthesized and used to encapsulate the LMC hybrid dispersions via ultrasonic cavitation to prepare DL-based nano-capsules (DLNCs). The DLNCs were used as the only active ingredient in sunscreens, whose sun protection factor (SPF) value could be up to 55 with a dosage of 10 wt%. Due to anti-photolysis property of DL, the SPF value of DLNCs-based sunscreens increased initially and maintained >8 h under UV irradiation. Additionally, the prepared DLNCs exhibited excellent anti-permeability, antioxidant capacity and biocompatibility, making them a potential substitute for conventional petroleum-based sunscreen agents.