Showing papers by "Donghua University published in 2023"

Electrogenerated quinone intermediates mediated peroxymonosulfate activation toward effective water decontamination and electrode antifouling

Abstract: The activation of peroxymonosulfate (PMS) by redox-active quinones-like compounds has been proposed as a viable approach for water decontamination, which is, however, limited by the secondary pollution associated with ex situ addition of organic activators. Herein, we demonstrated a novel in situ produced quinone intermediates-mediated PMS activation technique for organic decontamination. The parent pollutant (e.g., aniline) was first transformed to quinones-like intermediates by electrooxidation, followed by nucleophilic addition with PMS to initiate the production of singlet oxygen (1O2), which significantly improved the pollutant degradation and mineralization kinetics when compared to conventional electrooxidation technologies. Advanced characterizations and experimental evidence showed that the proposed method could significantly reduce electrode fouling, which is a common limitation of electrooxidation processes. The system could function efficiently across a pH range of 3–11. Experiments with genuine aniline-contaminated dyeing effluent confirmed the excellent system efficacy.

Reaction-induced macropore formation enabling commodity polymer derived carbons for CO₂ capture

Abstract: This work demonstrates a simple and scalable method for synthesizing porous carbons with high CO 2 uptake capacity.

Towards personalized privacy preference aware data trading: A contract theory based approach

Abstract: A large number of IoT devices geographically distributed in urban areas makes it attractive to collect massive data in a crowdsourced manner. To fully exploit the value of crowdsourced data, there has been a significant growth in demand for data trading recently. However, trading data exposes data owners to privacy violations. Existing studies based on centralized differential privacy are impractical due to the assumption of a trustworthy data collector, the high risk of privacy leakage, and extensive communication costs, let alone the data owners’ personalized requirements on privacy protection. To this end, we propose a contract theory-based personalized privacy-aware data trading approach that provides a set of optimal contracts specifying different privacy-preserving levels and data trading prices to selfish data owners who upload perturbed data according to the negotiated privacy-preserving level, and finally aggregates the data using a group-weighted maximum likelihood estimation method. The proposed private data trading approach not only achieves desirable data utility in terms of accuracy but also satisfies budget feasibility, individual rationality, and incentive compatibility through theoretical analysis and extensive experiments.

A multifunctional coating with silk fibroin/chitosan quaternary ammonium salt/heparin sodium for AZ31B magnesium alloy

Abstract: The magnesium (Mg) alloy is considered as one of the most promising metal materials for cardiovascular or bone stents. However, challenges still remain in its rapid degradation in the physiological environments and the limited surface biocompatibility. In this work, regenerated silk fibroin (RSF) coating was initially coated on the alkaline treated AZ31B Mg alloy. Afterward layer-by-layer (LbL) self-assembled process was carried out to deposit chitosan quaternary ammonium salt (HACC) and heparin (Hep) alternately on the RSF-coated sample. The morphological features, chemical structure, corrosion resistance and in vitro degradation behavior of the multilayer coating were investigated. The multilayer coating with a thickness of about 27 µm was uniform and adhered well to the Mg substrate. Compared to the naked Mg substrate, the corrosion current density of the sample with the multilayer coating decreased from 1.03 × 10−5 to 1.52 × 10−6A cm−2, and the corrosion potential shifted in the positive direction from − 1.62 V to − 1.44 V. The average degradation rate in SBF dropped to 0.34 mm/year from 2.3 mm/year of the pristine Mg substrate. The integrity of multilayer coating remained intact after immersion in SBF for 7 days. The platelet adhesion quantities and hemolysis rate (0.64 ± 0.24%) of sample with the multilayer coating were significantly decreased. The coated Mg alloy showed the improved cytocompatibility as compared to the uncoated Mg alloy according to the results of CCK-8 assay and fluorescence staining. Meanwhile, the multilayer coating exhibited good antibacterial activity, especially against S. aureus (94.7% inhibition rate). The above preliminary results highlighted the feasibility of the multilayer coating strategy and the potential of designing functional biopolymer coatings on Mg-based substrate for medical application.

Chicken utricle stromal cell-derived decellularized extracellular matrix coated nanofibrous scaffolds promote auditory cell production

Abstract: Stem cell therapy has a broad future in treating sensorineural hearing loss in mammals. But how to produce sufficient functional auditory cells including hair cells, supporting cells as well as spiral ganglion neurons from potential stem cells is the bottleneck. In this study, we aimed to simulate inner ear development microenvironment to induce inner ear stem cells to differentiate into auditory cells. The different mass ratios of poly-l-lactic acid/gelatin (PLLA/Gel) scaffolds were fabricated by electrospinning technology to mimic the structure of the native cochlear sensory epithelium. The chicken utricle stromal cells were isolated and cultured, and then seeded on the PLLA/Gel scaffolds. The chicken utricle stromal cell-derived decellularized extracellular matrix (U-dECM)-coated PLLA/Gel bioactive nanofiber scaffolds (U-dECM/PLLA/Gel) were prepared by decellularization. The U-dECM/PLLA/Gel scaffolds were used for culture of inner ear stem cells, and the effects of the modified scaffolds on the differentiation of inner ear stem cells were analyzed by RT-PCR and immunofluorescent staining. The results showed that U-dECM/PLLA/Gel scaffolds possessed good biomechanical properties can significantly promote the differentiation of inner ear stem cells and make them differentiate into auditory cells. Collectively, these findings indicated that U-dECM-coated biomimetic nanomaterials may be a promising strategy for auditory cell production.

Quantifying Coupling Effects Between Soil Matric Potential and Osmotic Potential

Abstract: Soil matric potential and osmotic potential are widely accepted as two independent components of total soil water potential. However, laboratory observations repeatedly demonstrated that matric potential can vary with salt concentration, implying a potential coupling between matric potential and osmotic potential. To date, it remains elusive whether matric potential and osmotic potential are independent or not and why so, and a theoretical theory for quantifying the coupling between them is still missing. Herein, a theoretical model is developed to quantitatively explain this problem via a lens provided by a recent concept of soil sorptive potential (SSP). The proposed model substantiates that matric potential and osmotic potential are not independent. The increasing salt concentration can notably depress two variables underpinning SSP, namely relative permittivity and electrical double layer thickness, leading to non-negligible decreasing (more negative) of matric potential in the high suction range, and increasing (less negative) of it in the low suction range. In turn, the soil-water interactions redistribute ions in soil water, raising osmotic potential especially for clay with high cation exchange capacity. The proposed model shows excellent performance in capturing experimental data, validating its accuracy. A parametric study implies that the neglection of coupling effects can lead to a significant underestimation of soil hydraulic conductivity in the film flow regime.

Preparation and properties of visible light-cured strippable film for radioactive decontamination

Abstract: In this research, solutions of styrene-butadiene-styrene block copolymer (SBS) in 2-ethoxyethyl methacrylate (EOEMA) were used to prepare strippable films via rapid visible-light curing, where the mixture of camphorquinone (CQ), diphenylsilane (DPS) and diphenyliodonium hexafluorophosphate (Iod) was employed as the photoinitiating system, [email protected] nm, sunlight or household LED panel light as the light source and no any solvent was involved. The double bond conversion for pure EOEMA under [email protected] nm was firstly monitored by real-time FTIR and it reached 72% within 300 s. The rapid-curing of SBS/EOEMA solutions were systematically investigated and it was found that the solution with 16 wt% SBS became completely dried at the presence of 2.16 mol% crosslinker and 3.6 wt% photoinitiating system after 240 s irradiation under [email protected] nm. The tensile strength, elongation at break and glass transition temperature of the resultant strippable film were determined to be about 4.4 ± 0.5 MPa, 130 ± 11.2% and 6.9 °C, respectively, by mechanical properties testing and DSC measurements. Also, the decontamination efficiencies (DE) of household LED panel light/sunlight cured-strippable film for uranium nitrate on stainless steel, glass, and ceramic surface were evaluated to be higher than 90%. These results indicate that this rapid-curing strippable films would be a good candidate material for large-scale radioactive decontamination.

Upper semicontinuity of pullback attractors for nonclassical diffusion equations with delay

Abstract: In this paper, we mainly study the upper semicontinuity of pullback D-attractors for a nonclassical diffusion equation with delay term b ( t , u t ) which contains some hereditary characteristics. Under a critical nonlinearity f, a time-dependent force g ( t , x ) with exponential growth and a delayed force term b ( t , u t ), using the asymptotic a priori estimate method, we prove the upper semicontinuity of pullback D-attractor { A ε ( t ) } t ∈ R to equation (1.1) with ε ∈ [ 0 , 1 ].

Nanoindentation‐induced evolution of atomic‐level properties in silicate glass: Insights from molecular dynamics simulations

Abstract: Indentation has been widely used for investigating the mechanical behavior of glasses. However, how the various microscopic properties (such as atomic structure and mechanics) of glass evolve from the immediate contact with the indenter to the far-field regions, and how these observables are correlated to each other remain largely unknown. Here, using large-scale molecular dynamics simulations, we investigate the response of a prototypical sodium silicate glass under shape contact load up to an indentation depth of 25 nm. Both the short- and intermediate-range structures are found to exhibit notable changes below the indent, indicating that indentation deformation induces a more disordered and heterogeneous network structure. In addition, we find that the indentation-induced changes of local properties all exhibit an exponential decaying behavior with increasing distance from the indent. Comparison of the characteristic decay lengths of these local properties indicates that the structural origins of shear flow and densification are the changes of the network modifier's coordination environment and the inter-tetrahedral connection, respectively. The decay of densification is considerably slower than that of shear strain, implying that the former might contribute more to the deformation at the far-field regions. Our findings not only contribute to an atomistic understanding of the indentation response of silicate glasses but also pave the way towards rational design of damage-resistant glassy materials. This article is protected by copyright. All rights reserved

3D Ultrasound Tomography Image Reconstruction Algorithm by GPU

Abstract: At present, X-ray technology, B-ultrasound and magnetic resonance imaging technology have more or less defects in the detection of female breast cancer, so the early detection of breast cancer is still a very important challenge. Ultrasound tomography (UT) can solve these problems very well. This project mainly uses the TVAL3 algorithm to reconstruct the original image from the information collected by the UT system for clinical use. TVAL3 algorithm involves a large number of matrix-vector multiplications and transposed matrix-vector multiplications, which will consume a lot of time if traditional CPU methods are used. For the characteristics of matrix-vector multiplication, this project uses CUDA to call GPU for parallel computing. At the same time, in order to further increase the speed of the calculation, we put part of the unchanged content into the GPU in advance to reduce the time spent on the transfer process. The final speedups of 20x, 10x and 5x were achieved in matrix vector multiplication, transpose matrix vector multiplication and total time, respectively.

Manganese‐Catalyzed Chemoselective Coupling of Secondary Alcohols, Primary Alcohols and Methanol

Abstract: Herein, we report a manganese-catalyzed three-component coupling of secondary alcohols, primary alcohols and methanol for the synthesis of β,β-methylated/alkylated secondary alcohols. Using our method, a series of 1-arylethanol, benzyl alcohol derivatives, and methanol undergo sequential coupling efficiently to construct assembled alcohols with high chemoselectivity in moderate to good yields. Mechanistic studies suggest that the reaction proceeds via methylation of a benzylated secondary alcohol intermediate to generate the final product.

Green‐Solvent‐Processed High‐Performance Ternary Organic Solar Cells Comprising a Highly Soluble and Fluorescent Third Component

Abstract: Nowadays, it is still a great challenge to obtain high-performance green-solvent-processed organic solar cells (OSCs). In this study, a ternary blend strategy (one donor and two acceptors, 1D/2A) is developed to solve the difficulty of film morphology modulation during the fabrication of high-performance green-solvent-processed OSCs. A typical high-performance halogenated-solvent processable binary system D18:BTP-eC9-4F is selected as the host, its green-solvents-processed devices show an inferior power conversion efficiency (PCE) of ≈16%. SM16 with two 3D shape persistent end groups is selected as the third component due to its high fluorescence quantum yield, reduced intermolecular interaction, good solubility, and moderate crystallinity. As a result, the ternary devices display bicontinuous interpenetrating networks, reduced energy loss, and suppressed charge carrier recombination losses. Hence, an excellent PCE of 18.20% is achieved for the D18:BTP-eC9-4F:SM16 ternary devices, which is much higher than D18:BTP-eC9-4F-based binary ones and also one of the highest PCEs for the green-solvents-processed OSCs. Besides, this strategy also demonstrates a good universality for other binary systems and becomes an effective pathway for the development of green-solvent processable high-performance OSCs.

Fabrication and braiding angle effect on the improved interlaminar shear performances of 3D braided sandwich hybrid composites

Abstract: While the interlaminar hybrid composites have been used widely and still remain in great demands, interlayer delamination, undesirable in most cases, keeps a common defect, due to the lack of interlaminar fiber-connection. Here, on the basis of the yarn interlacing rule in three-dimensional (3D) four-step braiding technology, 3D braided sandwich (S_) hybrid carbon fibers/Kevlar fibers composites with different braiding angles (S_20˚, S_30˚ and S_40˚) have been designed and fabricated with interlaminar fiber-connection. Short-beam shear tests were applied to evaluate the interlaminar shear performances of specimens and the in-situ strain maps during tests were characterized by digital image correlation (DIC) technique and specimen damages were observed using computed tomography (CT) method. Results showed that, comparing to the conventional co-cured laminated hybrid composites, 3D braided sandwich hybrid composites resist the delamination effectively by the fiber-connection hybrid region. Braiding effect of 3D braided sandwich hybrid composites revealed that S_20° showed better deformability and higher structural toughness than their counterparts in S_30° and S_40°. The results presented in the current work would be helpful for the design and manufacturing of well structured hybrid preforms and composites with dramatically improved interlaminar shear properties.