An eleetrochromic variable optical attenuator （ECVOA） was fabricated by layer-by-layer （LBL） assembly of disodium N,N-bis（p-sulfonatophenyl）naphthalenedicarboximide （Naph-SO3Na） and common cationic polymer pol...An eleetrochromic variable optical attenuator （ECVOA） was fabricated by layer-by-layer （LBL） assembly of disodium N,N-bis（p-sulfonatophenyl）naphthalenedicarboximide （Naph-SO3Na） and common cationic polymer poly（diallyldimethylammonium） chloride （PDDA）. The UV-Vis absorption spectra of the multilayer films revealed that approximately an equal amount of Naph-SO3Na was assembled in each deposition cycle. Upon one-electron reduction, multilayer films exhibited intense absorption around 452 nm and also a broad absorption band from 1200 nm to 1900 nm. Owing to the improved ionic conductivity, the optical attenuation at 1550 nm of the films showed rapid response time and reached 1.3 dB/μm within 5 s. These results indicate that layer-by-layer assembly could be an effective method for the preparation of ECVOA operating in near infrared region.展开更多
Metal oxide semiconductor materials such as ZnO have tremendous potential as light absorbers for photocatalysed electrodes in the electrochemical reduction of water. Promoters such as rGO have been added to reduce the...Metal oxide semiconductor materials such as ZnO have tremendous potential as light absorbers for photocatalysed electrodes in the electrochemical reduction of water. Promoters such as rGO have been added to reduce the recombination losses of charge carriers and improve its photoelectrochemical activity. In this study, the effect of layer ordering on the charge transfer properties of rGO-hybridised ZnO sandwich thin films for the photo-catalysed electrochemical reduction of water was investigated. rGO-hybridised ZnO sandwich thin films were prepared via a facile electrode position technique using a layer-by-layer approach. The thin films were analysed using FESEM, XRD, Raman, PL, UV–vis, EIS and CV techniques to investigate its morphological, optical and electrochemical properties. The FESEM images show the formation of distinct layers of rGO and ZnO nanorods/flakes via the layer-by-layer method. XRD confirmed the wurtzite structure of ZnO. PL spectroscopy revealed a reduction of photoemission intensity in the visible region（580 nm） when rGO was incorporated into the ZnO thin film. Among the six thin films prepared, ZnO/rGO showed superior performance compared to the other thin films（0.964 m A/cm） due to the presence of graphene edges which participate as heterogenous electrocatalysts in the photocatalysed electrolysis of water. rGO also acts as electron acceptor, forming an n-p heterojunction which improves the activity of ZnO to oxidise water molecules to O2. EIS revealed that the application of rGO as back contact（rGO/ZnO, rGO/ZnO/rGO） reduces the charge transfer resistance of a semiconductor thin film. Alternatively, rGO as front contact（ZnO/rGO, rGO/ZnO/rGO） improves the photo-catalysed electrolysis of water through the participation of the rGO edges in the chemical activation of water. The findings from this study indicate that the layer ordering significantly affects the thin film＇s electrostatic properties and this understanding can be further advantageous for tunable applications.展开更多
The layer-by-layer assembly of graphene oxide and diazoresin is carried out via the electrostatic and hydrogen bond interactions on planar substrates and colloidal templates.The successful planar and spherical growth ...The layer-by-layer assembly of graphene oxide and diazoresin is carried out via the electrostatic and hydrogen bond interactions on planar substrates and colloidal templates.The successful planar and spherical growth of multilayer could be investigated by UV-vis spectrophotometry and scanning electron microscopy,respectively.Subsequent UV irradiation or heating would convert the ionic bonds and hydrogen bonds to covalent bands,which significantly improves the stability of the multilayer composite against solvent etching.For the cross-linked core-shell composites,the template cores could be removed by dissolution and hollow microspheres are obtained.展开更多
Thin film composite(TFC) membranes represent a highly promising platform for efficient nanofiltration(NF)processes. However, the improvement in permeance is impeded by the substrates with low permeances. Herein,highly...Thin film composite(TFC) membranes represent a highly promising platform for efficient nanofiltration(NF)processes. However, the improvement in permeance is impeded by the substrates with low permeances. Herein,highly permeable gradient phenolic membranes with tight selectivity are used as substrates to prepare TFC membranes with high permeances by the layer-by-layer assembly method. The negatively charged phenolic substrates are alternately assembled with polycation polyethylenimine(PEI) and polyanion poly(acrylic acid)(PAA)as a result of electrostatic interactions, forming thin and compact PEI/PAA layers tightly attached to the substrate surface. Benefiting from the high permeances and tight surface pores of the gradient nanoporous structures of the substrates, the produced PEI/PAA membranes exhibit a permeance up to 506 L? m-2?h-1?MPa-1, which is ~2–10 times higher than that of other membranes with similar rejections. The PEI/PAA membranes are capable of retaining N 96.1% of negatively charged dyes following the mechanism of electrostatic repulsion. We demonstrate that the membranes can also separate positively and neutrally charged dyes from water via other mechanisms.This work opens a new avenue for the design and preparation of high-flux NF membranes, which is also applicable to enhance the permeance of other TFC membranes.展开更多
A simple and controllable layer-by-layer （LBL） assembly method was proposed for the construction of reagentless biosensors based on electrostatic interaction between functional multiwall carbon nanotubes （MWNTs） a...A simple and controllable layer-by-layer （LBL） assembly method was proposed for the construction of reagentless biosensors based on electrostatic interaction between functional multiwall carbon nanotubes （MWNTs） and enzyme-mediator biocomposites. The carboxylated MWNTs were wrapped with polycations poly（allylamine hydrochloride） （PAH） and the resulting PAH-MWNTs were well dispersed and positively charged. As a water-soluble dye methylene blue （MB） could mix well with horseradish peroxidase （HRP） to form a biocompatible and negativelycharged HRP-MB biocomposite. A （PAH-MWNTs/HRP-MB）, bionanomultilayer was then prepared by electrostatic LBL assembly of PAH-MWNTs and HRP-MB on a polyelectrolyte precursor film-modified Au electrode. Due to the excellent biocompatibility of HRP-MB biocomposite and the uniform LBL assembly, the immobilized HRP could retain its natural bioactivity and MB could efficiently shuttle electrons between HRP and the electrode. The incorporation of MWNTs in the bionanomultilayer enhanced the surface coverage concentration of the electroactive enzyme and increased the catalytic current response of the electrode. The proposed biosensor displayed a fast response （2 s） to hydrogen peroxide with a low detection limit of 2.0× 10^-7 mol/L （S/N=3）. This work provided a versatile platform in the further development of reagentless biosensors.展开更多
In order to develop a facile and precisely controlled approach to synthesize hierarchical mesoporous materials with tailored property, in this work, a novel study was carried out to fabricate montmorillonitechitosan h...In order to develop a facile and precisely controlled approach to synthesize hierarchical mesoporous materials with tailored property, in this work, a novel study was carried out to fabricate montmorillonitechitosan hollow and hierarchical mesoporous spheres(MMTNS@CS-HMPHS) based on single-template layer-by-layer(Lb L) assembly. Scanning electron microscopy(SEM), transmission electron microscopy(TEM), specific surface area analysis and X-ray photoelectron spectroscopy(XPS) analyses were carried out to characterize the morphology and surface properties of MMTNS@CS-HMPHS. Benefitting from the unique lamellar structure of MMTNS, mesoporous channels are formed on the shell of MMTNS@CS hollow spheres, resulting in high surface area. Moreover, the surface functionalization and pore size of MMTNS@CS-HMPHS can be easily tuned, due to the tailored property through Lb L assembly method.Besides the unique microstructure, MMTNS@CS-HMPHS also possesses the active sites generated from both MMT and chitosan, which greatly promotes its performance in fields of adsorption, drug delivery and catalyst supports, etc.展开更多
Layer-by-layer(LbL)assembly technology is a facile method for constructing thin film composite membrane.Herein,a novel nanofiltration(NF)membrane was prepared by LbL assembly of polyethyleneimine(PEI)and sodium lignos...Layer-by-layer(LbL)assembly technology is a facile method for constructing thin film composite membrane.Herein,a novel nanofiltration(NF)membrane was prepared by LbL assembly of polyethyleneimine(PEI)and sodium lignosulfonate(LS)followed by cross-linking.The surface composition,morphology,and property of PEI/LS bilayer were detailedly investigated by FTIR/ATR,XPS,SEM,AFM,and water contact angle test.The PEI/LS bilayer full of amino and hydroxyl groups presents increased roughness and improved hydrophilicity.Moreover,the NF performance of PEI/LS LbL assembly membranes can be modulated by bilayer number,polyelectrolyte concentration,and salt content.The water flux reduced while the salt rejection greatly improved as increasing the bilayer numbers,PEI concentration,or NaCl content.More than 95%MgSO4 and MgCl2,as well as 80%NaCl can be rejected by a NF membrane prepared by 6 PEI/LS bilayers,1 wt%PEI,0.5 wt%LS,and 1 mol/L NaCl.Furthermore,this NF membrane can be used to remove more than 95%heavy metal ions(Cd2+,Zn2+,Mn2+,Cr2+,Cu2+,and Ni2+).This work proposed a promising NF membrane by using PEI/LS as low cost polyelectrolytes and facile LbL assembly method,which should receive much attention in water purification.展开更多
Layer-by-layer(LBL)assembly shows great potential in fabrication of flexible conductive cotton fabrics(FCCF)with carbon nanotubes(CNT)as conductive components but is limited because complicated chemical modification o...Layer-by-layer(LBL)assembly shows great potential in fabrication of flexible conductive cotton fabrics(FCCF)with carbon nanotubes(CNT)as conductive components but is limited because complicated chemical modification of CNT is usually required.Herein,we reported a facile and eco-friendly LBL approach to fabricating FCCF by dipping in chitosan(CS)aqueous solution and poly(sodium 4-styrenesulfonate)(PSS)wrapped CNT aqueous dispersion alternately.The FCCF with electrical conductivity higher than 30 S/m was achieved when 4 layers of CNT were coated on the cotton fabric(CF).The obtained FCCF possessed outstanding mechanical stability with electrical resistivity almost unchanged after exposure to 500 times mechanical abrasion and 500 circles of tape peeling.The FCCF showed excellent strain sensing performance with high sensitivity(with a gauge factor up to 35.1)and a fast response time(70 ms).It can be used as a strain sensor to accurately detect various human deformations such as finger bending and joint movements.The FCCF could be used as a temperature sensor in that it exhibited stable and reproducible negative temperature sensing behavior in the temperature range of 30-100℃.展开更多
The simple LBL technique was introduced to fabricate green nacre-like chatosan/montmorillonite （CHI/MMT） films. The results of SEM and XRD analysis demonstrate that the produced CHI/MMT composites films stacked dens...The simple LBL technique was introduced to fabricate green nacre-like chatosan/montmorillonite （CHI/MMT） films. The results of SEM and XRD analysis demonstrate that the produced CHI/MMT composites films stacked densely together to bring out well-defined nacre-like brick-mortar structure. The nanoindentation technique is used to characterize the mechanical properties of the layered nanocomposite films, which show enhanced mechanical modulus （up to -6.64 GPa） compared with the pure chitosan.展开更多
A novel reagentless biosensor constructed by the organic dye nile blue (NB) and horseradish peroxidase (HRP) has been fabricated via layer-by-layer (LBL) self-assembly technique. NB premixed with polyanion poly (sodiu...A novel reagentless biosensor constructed by the organic dye nile blue (NB) and horseradish peroxidase (HRP) has been fabricated via layer-by-layer (LBL) self-assembly technique. NB premixed with polyanion poly (sodium-p-styrenesulfonate) (PSS) acts as the mediator between the immobilized HRP and the electrode surface. The response of the biosensor to hydrogen peroxide has been investigated. The linear range of the biosensor to hydrogen peroxide was from 0.20 mmol/L to 7.03 mmol /L with a sensitivity of 8.45 μA/(mmol/L).展开更多
Polystyrene （PS） @SiO2 core-shell microbeads with large pore and large particle size were prepared via layer-by-layer（LBL）assembly technique for potential applications in nano-micro composites. Negative silica nan...Polystyrene （PS） @SiO2 core-shell microbeads with large pore and large particle size were prepared via layer-by-layer（LBL）assembly technique for potential applications in nano-micro composites. Negative silica nanoparticles synthesized via modified St6ber method and cationic poly （diallyldimethylammonium chloride） were alternately adsorbed on the surface of microbeads. Zeta potential, size, and morphology of the microbeads were monitored during LBL assembly process to ensure the successful deposition of silica nanoparticles. The porous shell was characterized using nitrogen adsorption and desorption analyses, and the surface area, volume and diame- ter of the pores were derived. It is found that the porous shell thickness and the pore size can be tuned by changing the coating times of silica nanoparticles. Finally, PS@SiO2 core-shell microbeads with 5 grn PS solid core and 350 nm mesoporous shell （mean BJH pore diameter is ~27 nm） were used to load CdSe/ZnS quantum dots （QDs）. The fluorescence microscopic image and the optical amplification of the QDs-embedded microbeads （QDBs） indicate that the as-prepared core-shell microbeads can provide adequate space for QDs and may be useful for further application of nano-micro composites.展开更多
Polyelectrolyte/polyelectrolyte, organic molecule/colloidal CdS and polyelectrolyte/MWCNT films were fabricated via the layer-by-layer assembling technique. The assembled films were characterized by UV-vis spectrophot...Polyelectrolyte/polyelectrolyte, organic molecule/colloidal CdS and polyelectrolyte/MWCNT films were fabricated via the layer-by-layer assembling technique. The assembled films were characterized by UV-vis spectrophotometer, X-ray diffractometry, nano profilometer and scanning electron microscopy. The results demonstrate that the layer-by-layer assembling technique can be used to make the nanoscaled films from polyelectrolytes and thicker composite films from suitable precursor materials. Both organic molecule/colloidal CdS films and PEI/MWCNT films with thickness of hundreds of nanometers were obtained. For the organic molecule/colloidal CdS films, a reasonable explanation for the result is that both the organic molecules and the CdS particles aggregate in the films. For the PEI/MWCNT films, obviously, it is the MWCNT that makes the great contribution to the film thickness.展开更多
Polyelectrolyte-doped microcapsules(PDM)was fabricated by coaxial electrospray of a mixture of glycerol and water containing 10 mg/mL cationic polyelectrolyte poly(allylamine hydrochloride)(PAH)fed as the core phase s...Polyelectrolyte-doped microcapsules(PDM)was fabricated by coaxial electrospray of a mixture of glycerol and water containing 10 mg/mL cationic polyelectrolyte poly(allylamine hydrochloride)(PAH)fed as the core phase solution,and a N,N-dimethylacetylamide solution of 10 wt%polyurethane fed as the shell phase solution.Multienzyme system involving Candida Antarctica lipase B(CALB),glucose oxidase(GOD),and horseradish peroxidase(HRP)for cascade reaction was assembled in the PDM at three different places,namely,surface,shell,and lumen.Placing of enzyme inside aqueous lumen of the PDM was realized by in situ encapsulation through adding the enzyme in the core-phase solution for coaxial electrospray.By ion-pairing of enzyme with cationic surfactant CTAB,an organic soluble enzyme-CTAB complex was prepared,so that in situ embedding of enzyme in the shell of the PDM was realized by adding it into the shell phase solution.Surface attachment of enzymes was achieved by layer-by-layer(LbL)technology,which is based on the ion-exchange interactions between oppositely charged enzymes and PAH that was doped in PDM.The enzyme-decorated microcapsule was then studied as a microbioreactor,in which 1-Oxododecyla-α-glucopyranoside was converted by CALB to glucose,which was oxidised by GOD to gluconolactone in a second step.The hydrogen peroxide produced was then used by HRP to oxidize ABTS to form coloured radical cation ABTS•+for activity analysis.The successful fabrication of the PDM and precise localization of enzymes in the PDM by different strategies were fully characterized.By varying the immobilization strategy,totally six PDM bioreactors with three enzymes precisely positional assembled in different strategies were constructed and their activities for the cascade reaction were investigated and compared.The PDM micro-bioreactor prepared by novel electrospray technologies provide a smart platform for positional assembly of multi-enzyme cascade reaction in a precise and well-controlled manner.展开更多
To enhance the corrosion resistance of magnesium（Mg） alloy and to impart its surface with antibacterial functionality for inhibiting biofilm formation and biocorrosion, Mg（OH）2 films were fabricated on AZ31 magnes...To enhance the corrosion resistance of magnesium（Mg） alloy and to impart its surface with antibacterial functionality for inhibiting biofilm formation and biocorrosion, Mg（OH）2 films were fabricated on AZ31 magnesium alloy substrates by an in-situ hydrothermal method and well-defined multilayer coatings, consisting of gentamicin sulfate（GS） and poly（sodium 4-styrene sulfonate）（PSS）, were prepared via layer-by-layer（Lb L） assembly. The morphologies, chemical compositions and corrosion resistance of the obtained（PSS/GS）n/Mg sample were investigated using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, electrochemical methods and immersion tests. Finally, the bactericidal activity of（PSS/GS）n/Mg samples against Staphylococcus aureus was assessed by the zone of inhibition methods and plate-counting method. The so-synthesized composite coating on the Mg alloy substrates exhibits good corrosion resistance and antibacterial performance, which make them attractive as coatings for medical implanted devices.展开更多
Microorganisms can colonize the surface of microplastics(MPs)to form a distinctive microbiome,known as a“plastisphere”which is regarded as an anthropogenic niche for microbial growth.However,bacterial community asse...Microorganisms can colonize the surface of microplastics(MPs)to form a distinctive microbiome,known as a“plastisphere”which is regarded as an anthropogenic niche for microbial growth.However,bacterial community assembly in virgin and aging MP plastispheres across different habitats is poorly understood.This study aims to assess the variations in bacterial community assembly across different niches and habitats with an in situ ex-periment,in which constructed forest wetland(FW),natural lake wetland(LW),and lotus pond wetland(LP)were habitats,and plastispheres of virgin and aging low-density polyethylene(LDPE)MPs,as well as surround-ing wetland soils were niches.Significant niche-related differences in bacterial communities were observed,with lower diversity and enrichment of potential plastic-degrading bacteria in the plastisphere than in the soil bacterial communities.Furthermore,habitat-related differences exerted a more pronounced influence on the beta-diversity patterns of the bacterial communities.The linear regression analyses indicated that the local species pool con-tributed more to bacterial community assembly in the LW wetland,whereas the relative abundance of species was the primary factor in the LP wetland.The null model analysis indicated that plastisphere bacterial communi-ties were predominantly driven by the stochastic process,with a more deterministic assembly observed in the LP wetland and soil bacterial communities.Additionally,the primary ecological process shaping plastisphere com-munities shifted from drift in the virgin LDPE to homogenising dispersal in the aging LDPE.This study provides new insights into the fate and ecological impacts of MPs in wetlands,thereby facilitating the effective regulations of plastic pollution.展开更多
Transformer-based models have significantly advanced binary code similarity detection(BCSD)by leveraging their semantic encoding capabilities for efficient function matching across diverse compilation settings.Althoug...Transformer-based models have significantly advanced binary code similarity detection(BCSD)by leveraging their semantic encoding capabilities for efficient function matching across diverse compilation settings.Although adversarial examples can strategically undermine the accuracy of BCSD models and protect critical code,existing techniques predominantly depend on inserting artificial instructions,which incur high computational costs and offer limited diversity of perturbations.To address these limitations,we propose AIMA,a novel gradient-guided assembly instruction relocation method.Our method decouples the detection model into tokenization,embedding,and encoding layers to enable efficient gradient computation.Since token IDs of instructions are discrete and nondifferentiable,we compute gradients in the continuous embedding space to evaluate the influence of each token.The most critical tokens are identified by calculating the L2 norm of their embedding gradients.We then establish a mapping between instructions and their corresponding tokens to aggregate token-level importance into instructionlevel significance.To maximize adversarial impact,a sliding window algorithm selects the most influential contiguous segments for relocation,ensuring optimal perturbation with minimal length.This approach efficiently locates critical code regions without expensive search operations.The selected segments are relocated outside their original function boundaries via a jump mechanism,which preserves runtime control flow and functionality while introducing“deletion”effects in the static instruction sequence.Extensive experiments show that AIMA reduces similarity scores by up to 35.8%in state-of-the-art BCSD models.When incorporated into training data,it also enhances model robustness,achieving a 5.9%improvement in AUROC.展开更多
Aircraft assembly is characterized by stringent precedence constraints,limited resource availability,spatial restrictions,and a high degree of manual intervention.These factors lead to considerable variability in oper...Aircraft assembly is characterized by stringent precedence constraints,limited resource availability,spatial restrictions,and a high degree of manual intervention.These factors lead to considerable variability in operator workloads and significantly increase the complexity of scheduling.To address this challenge,this study investigates the Aircraft Pulsating Assembly Line Scheduling Problem(APALSP)under skilled operator allocation,with the objective of minimizing assembly completion time.A mathematical model considering skilled operator allocation is developed,and a Q-Learning improved Particle Swarm Optimization algorithm(QLPSO)is proposed.In the algorithm design,a reverse scheduling strategy is adopted to effectively manage large-scale precedence constraints.Moreover,a reverse sequence encoding method is introduced to generate operation sequences,while a time decoding mechanism is employed to determine completion times.The problem is further reformulated as a Markov Decision Process(MDP)with explicitly defined state and action spaces.Within QLPSO,the Q-learning mechanism adaptively adjusts inertia weights and learning factors,thereby achieving a balance between exploration capability and convergence performance.To validate the effectiveness of the proposed approach,extensive computational experiments are conducted on benchmark instances of different scales,including small,medium,large,and ultra-large cases.The results demonstrate that QLPSO consistently delivers stable and high-quality solutions across all scenarios.In ultra-large-scale instances,it improves the best solution by 25.2%compared with the Genetic Algorithm(GA)and enhances the average solution by 16.9%over the Q-learning algorithm,showing clear advantages over the comparative methods.These findings not only confirm the effectiveness of the proposed algorithm but also provide valuable theoretical references and practical guidance for the intelligent scheduling optimization of aircraft pulsating assembly lines.展开更多
Modern manufacturing processes have become more reliant on automation because of the accelerated transition from Industry 3.0 to Industry 4.0.Manual inspection of products on assembly lines remains inefficient,prone t...Modern manufacturing processes have become more reliant on automation because of the accelerated transition from Industry 3.0 to Industry 4.0.Manual inspection of products on assembly lines remains inefficient,prone to errors and lacks consistency,emphasizing the need for a reliable and automated inspection system.Leveraging both object detection and image segmentation approaches,this research proposes a vision-based solution for the detection of various kinds of tools in the toolkit using deep learning(DL)models.Two Intel RealSense D455f depth cameras were arranged in a top down configuration to capture both RGB and depth images of the toolkits.After applying multiple constraints and enhancing them through preprocessing and augmentation,a dataset consisting of 3300 annotated RGB-D photos was generated.Several DL models were selected through a comprehensive assessment of mean Average Precision(mAP),precision-recall equilibrium,inference latency(target≥30 FPS),and computational burden,resulting in a preference for YOLO and Region-based Convolutional Neural Networks(R-CNN)variants over ViT-based models due to the latter’s increased latency and resource requirements.YOLOV5,YOLOV8,YOLOV11,Faster R-CNN,and Mask R-CNN were trained on the annotated dataset and evaluated using key performance metrics(Recall,Accuracy,F1-score,and Precision).YOLOV11 demonstrated balanced excellence with 93.0%precision,89.9%recall,and a 90.6%F1-score in object detection,as well as 96.9%precision,95.3%recall,and a 96.5%F1-score in instance segmentation with an average inference time of 25 ms per frame(≈40 FPS),demonstrating real-time performance.Leveraging these results,a YOLOV11-based windows application was successfully deployed in a real-time assembly line environment,where it accurately processed live video streams to detect and segment tools within toolkits,demonstrating its practical effectiveness in industrial automation.The application is capable of precisely measuring socket dimensions by utilising edge detection techniques on YOLOv11 segmentation masks,in addition to detection and segmentation.This makes it possible to do specification-level quality control right on the assembly line,which improves the ability to examine things in real time.The implementation is a big step forward for intelligent manufacturing in the Industry 4.0 paradigm.It provides a scalable,efficient,and accurate way to do automated inspection and dimensional verification activities.展开更多
Drug-eluting magnesium(Mg)alloy stents have a slower degradation rate and lower restenosis rate compared with uncoated stents,demonstrating good clinical efficacy.However,the release of anti-hyperplasia drugs from coa...Drug-eluting magnesium(Mg)alloy stents have a slower degradation rate and lower restenosis rate compared with uncoated stents,demonstrating good clinical efficacy.However,the release of anti-hyperplasia drugs from coatings delays endothelial tissue repair,thus leading to late stent thrombosis.To address these issues,a dual self-healed coating with various biological properties was fabricated on magnesium fluoride/polydopamine(MgF_(2)/PDA)-treated Mg alloys by spraying-assisted layer-by-layer(LBL)self-assembly of chitosan(CS),gallic acid(GA),and 3-aminobenzeneboronic acid-modified hyaluronic acid(HA-ABBA).The LBL coating,approximately 1.50μm thick,exhibited a uniform morphology with good adhesion strength(~1065 mN).The annual corrosion rate(Pi)of LBL samples was~1400 times slower than that of the Mg substrate,due to the physical barrier function provided by MgF_(2)/PDA layers and the dual self-healed ability of LBL layers.The rapid self-healing ability(with a healing period of~4 h under dynamic/static conditions)resulted from the synergistic interplay between the recombination of diverse chemical bonds within the LBL coating and the coordination of LBL-released GA with Mg2+,as corroborated by computer simulations.Compared with the drug-eluting coatings,the LBL sample demonstrated substantial advantages in anti-oxidation,anti-denaturation of fibrinogen,anti-platelet adhesion,anti-inflammation,anti-hyperplasia,and promoted-endothelialization.These benefits effectively address the limitations associated with drug-eluting coatings.展开更多
Polypropylene（PP） meltblown fibers were coated with titanium dioxide（Ti O2） nanoparticles using layer-by-layer（Lb L） deposition technique. The fibers were first modified with 3layers of poly（4-styrenesulfonic a...Polypropylene（PP） meltblown fibers were coated with titanium dioxide（Ti O2） nanoparticles using layer-by-layer（Lb L） deposition technique. The fibers were first modified with 3layers of poly（4-styrenesulfonic acid）（PSS） and poly（diallyl-dimethylammonium chloride）（PDADMAC） to improve the anchoring of the Ti O2 nanoparticle clusters. PDADMAC, which is positively charged, was then used as counter polyelectrolyte in tandem with anionic Ti O2 nanoparticles to construct Ti O2/PDADMAC bilayer in the Lb L fashion. The number of deposited Ti O2/PDADMAC layers was varied from 1 to 7 bilayer, and could be used to adjust Ti O2 loading. The Lb L technique showed higher Ti O2 loading efficiency than the impregnation approach. The modified fibers were tested for their photocatalytic activity against a model dye, Methylene Blue（MB）. Results showed that the Ti O2 modified fibers exhibited excellent photocatalytic activity efficiency similar to that of Ti O2 powder dispersed in solution. The deposition of Ti O23 bilayer on the PP substrate was sufficient to produce nanocomposite fibers that could bleach the MB solution in less than 4 hr.Ti O2-Lb L constructions also preserved Ti O2 adhesion on substrate surface after 1 cycle of photocatalytic test. Successive photocatalytic test showed decline in MB reduction rate with loss of Ti O2 particles from the substrate outer surface. However, even in the third cycle, the Ti O2 modified fibers are still moderately effective as it could remove more than 95% of MB after 8 hr of treatment.展开更多
基金supported by the National Natural Science Foundation of China(Nos.20674001,20325415, 20834001)the Research Fund for Doctoral Program of Higher Education of MOE of China(No.20060001029)
文摘An eleetrochromic variable optical attenuator （ECVOA） was fabricated by layer-by-layer （LBL） assembly of disodium N,N-bis（p-sulfonatophenyl）naphthalenedicarboximide （Naph-SO3Na） and common cationic polymer poly（diallyldimethylammonium） chloride （PDDA）. The UV-Vis absorption spectra of the multilayer films revealed that approximately an equal amount of Naph-SO3Na was assembled in each deposition cycle. Upon one-electron reduction, multilayer films exhibited intense absorption around 452 nm and also a broad absorption band from 1200 nm to 1900 nm. Owing to the improved ionic conductivity, the optical attenuation at 1550 nm of the films showed rapid response time and reached 1.3 dB/μm within 5 s. These results indicate that layer-by-layer assembly could be an effective method for the preparation of ECVOA operating in near infrared region.
基金the Ministry of Higher Education High Impact Research (HIR F000032)the University of Malaya (RP022-2012A)for their generous financial support, and the Nanotechnology and Catalysis Research Centre (NANOCAT) for their analytical services
文摘Metal oxide semiconductor materials such as ZnO have tremendous potential as light absorbers for photocatalysed electrodes in the electrochemical reduction of water. Promoters such as rGO have been added to reduce the recombination losses of charge carriers and improve its photoelectrochemical activity. In this study, the effect of layer ordering on the charge transfer properties of rGO-hybridised ZnO sandwich thin films for the photo-catalysed electrochemical reduction of water was investigated. rGO-hybridised ZnO sandwich thin films were prepared via a facile electrode position technique using a layer-by-layer approach. The thin films were analysed using FESEM, XRD, Raman, PL, UV–vis, EIS and CV techniques to investigate its morphological, optical and electrochemical properties. The FESEM images show the formation of distinct layers of rGO and ZnO nanorods/flakes via the layer-by-layer method. XRD confirmed the wurtzite structure of ZnO. PL spectroscopy revealed a reduction of photoemission intensity in the visible region（580 nm） when rGO was incorporated into the ZnO thin film. Among the six thin films prepared, ZnO/rGO showed superior performance compared to the other thin films（0.964 m A/cm） due to the presence of graphene edges which participate as heterogenous electrocatalysts in the photocatalysed electrolysis of water. rGO also acts as electron acceptor, forming an n-p heterojunction which improves the activity of ZnO to oxidise water molecules to O2. EIS revealed that the application of rGO as back contact（rGO/ZnO, rGO/ZnO/rGO） reduces the charge transfer resistance of a semiconductor thin film. Alternatively, rGO as front contact（ZnO/rGO, rGO/ZnO/rGO） improves the photo-catalysed electrolysis of water through the participation of the rGO edges in the chemical activation of water. The findings from this study indicate that the layer ordering significantly affects the thin film＇s electrostatic properties and this understanding can be further advantageous for tunable applications.
基金supported by the Natural Science Foundation of China(Nos.21173266 and 21473250)the Fundamental Research Funds for the Central Universitiesthe Research Funds of Renmin University of China(No.11XNJ021)
文摘The layer-by-layer assembly of graphene oxide and diazoresin is carried out via the electrostatic and hydrogen bond interactions on planar substrates and colloidal templates.The successful planar and spherical growth of multilayer could be investigated by UV-vis spectrophotometry and scanning electron microscopy,respectively.Subsequent UV irradiation or heating would convert the ionic bonds and hydrogen bonds to covalent bands,which significantly improves the stability of the multilayer composite against solvent etching.For the cross-linked core-shell composites,the template cores could be removed by dissolution and hollow microspheres are obtained.
基金Supported by the National Basic Research Program of China(2015CB655301)the Natural Science Foundation of China(21825803)+2 种基金and the Natural Science Foundation of Jiangsu Province(BK20150063)the Program of Excellent Innovation Teams of Jiangsu Higher Education Institutionsthe Project of Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘Thin film composite(TFC) membranes represent a highly promising platform for efficient nanofiltration(NF)processes. However, the improvement in permeance is impeded by the substrates with low permeances. Herein,highly permeable gradient phenolic membranes with tight selectivity are used as substrates to prepare TFC membranes with high permeances by the layer-by-layer assembly method. The negatively charged phenolic substrates are alternately assembled with polycation polyethylenimine(PEI) and polyanion poly(acrylic acid)(PAA)as a result of electrostatic interactions, forming thin and compact PEI/PAA layers tightly attached to the substrate surface. Benefiting from the high permeances and tight surface pores of the gradient nanoporous structures of the substrates, the produced PEI/PAA membranes exhibit a permeance up to 506 L? m-2?h-1?MPa-1, which is ~2–10 times higher than that of other membranes with similar rejections. The PEI/PAA membranes are capable of retaining N 96.1% of negatively charged dyes following the mechanism of electrostatic repulsion. We demonstrate that the membranes can also separate positively and neutrally charged dyes from water via other mechanisms.This work opens a new avenue for the design and preparation of high-flux NF membranes, which is also applicable to enhance the permeance of other TFC membranes.
基金Project (Nos.20805043 and 30800247) supported by the National Natural Science Foundation of China
文摘A simple and controllable layer-by-layer （LBL） assembly method was proposed for the construction of reagentless biosensors based on electrostatic interaction between functional multiwall carbon nanotubes （MWNTs） and enzyme-mediator biocomposites. The carboxylated MWNTs were wrapped with polycations poly（allylamine hydrochloride） （PAH） and the resulting PAH-MWNTs were well dispersed and positively charged. As a water-soluble dye methylene blue （MB） could mix well with horseradish peroxidase （HRP） to form a biocompatible and negativelycharged HRP-MB biocomposite. A （PAH-MWNTs/HRP-MB）, bionanomultilayer was then prepared by electrostatic LBL assembly of PAH-MWNTs and HRP-MB on a polyelectrolyte precursor film-modified Au electrode. Due to the excellent biocompatibility of HRP-MB biocomposite and the uniform LBL assembly, the immobilized HRP could retain its natural bioactivity and MB could efficiently shuttle electrons between HRP and the electrode. The incorporation of MWNTs in the bionanomultilayer enhanced the surface coverage concentration of the electroactive enzyme and increased the catalytic current response of the electrode. The proposed biosensor displayed a fast response （2 s） to hydrogen peroxide with a low detection limit of 2.0× 10^-7 mol/L （S/N=3）. This work provided a versatile platform in the further development of reagentless biosensors.
基金supported financially by the National Natural Science Foundation of China (Nos. 51874220 and 51674183)the Natural Science Foundation of Hubei Province of China (No. 2018CFB468)the Excellent Dissertation Cultivation Funds of Wuhan University of Technology (No. 2018-YS-050)
文摘In order to develop a facile and precisely controlled approach to synthesize hierarchical mesoporous materials with tailored property, in this work, a novel study was carried out to fabricate montmorillonitechitosan hollow and hierarchical mesoporous spheres(MMTNS@CS-HMPHS) based on single-template layer-by-layer(Lb L) assembly. Scanning electron microscopy(SEM), transmission electron microscopy(TEM), specific surface area analysis and X-ray photoelectron spectroscopy(XPS) analyses were carried out to characterize the morphology and surface properties of MMTNS@CS-HMPHS. Benefitting from the unique lamellar structure of MMTNS, mesoporous channels are formed on the shell of MMTNS@CS hollow spheres, resulting in high surface area. Moreover, the surface functionalization and pore size of MMTNS@CS-HMPHS can be easily tuned, due to the tailored property through Lb L assembly method.Besides the unique microstructure, MMTNS@CS-HMPHS also possesses the active sites generated from both MMT and chitosan, which greatly promotes its performance in fields of adsorption, drug delivery and catalyst supports, etc.
基金Zhejiang Provincial Natural Science Foundation of China(No.LY18E030002)Natural Science Foundation of Ningbo(No.2018A610111)K.C.Wong Magna Fund in Ningbo University.
文摘Layer-by-layer(LbL)assembly technology is a facile method for constructing thin film composite membrane.Herein,a novel nanofiltration(NF)membrane was prepared by LbL assembly of polyethyleneimine(PEI)and sodium lignosulfonate(LS)followed by cross-linking.The surface composition,morphology,and property of PEI/LS bilayer were detailedly investigated by FTIR/ATR,XPS,SEM,AFM,and water contact angle test.The PEI/LS bilayer full of amino and hydroxyl groups presents increased roughness and improved hydrophilicity.Moreover,the NF performance of PEI/LS LbL assembly membranes can be modulated by bilayer number,polyelectrolyte concentration,and salt content.The water flux reduced while the salt rejection greatly improved as increasing the bilayer numbers,PEI concentration,or NaCl content.More than 95%MgSO4 and MgCl2,as well as 80%NaCl can be rejected by a NF membrane prepared by 6 PEI/LS bilayers,1 wt%PEI,0.5 wt%LS,and 1 mol/L NaCl.Furthermore,this NF membrane can be used to remove more than 95%heavy metal ions(Cd2+,Zn2+,Mn2+,Cr2+,Cu2+,and Ni2+).This work proposed a promising NF membrane by using PEI/LS as low cost polyelectrolytes and facile LbL assembly method,which should receive much attention in water purification.
基金financially supported by the Natural Science Foundation of Chongqing,China(No.cstc2021jcyj-msxmX0943)the Chongqing Talent Plan for Young Top-Notch Talents(No.CQYC2021059217)the Foundation of Science and Technology Department of Sichuan Province(No.2022YFH0019).
文摘Layer-by-layer(LBL)assembly shows great potential in fabrication of flexible conductive cotton fabrics(FCCF)with carbon nanotubes(CNT)as conductive components but is limited because complicated chemical modification of CNT is usually required.Herein,we reported a facile and eco-friendly LBL approach to fabricating FCCF by dipping in chitosan(CS)aqueous solution and poly(sodium 4-styrenesulfonate)(PSS)wrapped CNT aqueous dispersion alternately.The FCCF with electrical conductivity higher than 30 S/m was achieved when 4 layers of CNT were coated on the cotton fabric(CF).The obtained FCCF possessed outstanding mechanical stability with electrical resistivity almost unchanged after exposure to 500 times mechanical abrasion and 500 circles of tape peeling.The FCCF showed excellent strain sensing performance with high sensitivity(with a gauge factor up to 35.1)and a fast response time(70 ms).It can be used as a strain sensor to accurately detect various human deformations such as finger bending and joint movements.The FCCF could be used as a temperature sensor in that it exhibited stable and reproducible negative temperature sensing behavior in the temperature range of 30-100℃.
基金financially supported by the National Basic Research Program of China(No.2010CB934700)the Doctoral Fund of Innovation of Beijing University of Technology
文摘The simple LBL technique was introduced to fabricate green nacre-like chatosan/montmorillonite （CHI/MMT） films. The results of SEM and XRD analysis demonstrate that the produced CHI/MMT composites films stacked densely together to bring out well-defined nacre-like brick-mortar structure. The nanoindentation technique is used to characterize the mechanical properties of the layered nanocomposite films, which show enhanced mechanical modulus （up to -6.64 GPa） compared with the pure chitosan.
文摘A novel reagentless biosensor constructed by the organic dye nile blue (NB) and horseradish peroxidase (HRP) has been fabricated via layer-by-layer (LBL) self-assembly technique. NB premixed with polyanion poly (sodium-p-styrenesulfonate) (PSS) acts as the mediator between the immobilized HRP and the electrode surface. The response of the biosensor to hydrogen peroxide has been investigated. The linear range of the biosensor to hydrogen peroxide was from 0.20 mmol/L to 7.03 mmol /L with a sensitivity of 8.45 μA/(mmol/L).
基金Supported by the National Natural Science Foundation of China(No.51202160)
文摘Polystyrene （PS） @SiO2 core-shell microbeads with large pore and large particle size were prepared via layer-by-layer（LBL）assembly technique for potential applications in nano-micro composites. Negative silica nanoparticles synthesized via modified St6ber method and cationic poly （diallyldimethylammonium chloride） were alternately adsorbed on the surface of microbeads. Zeta potential, size, and morphology of the microbeads were monitored during LBL assembly process to ensure the successful deposition of silica nanoparticles. The porous shell was characterized using nitrogen adsorption and desorption analyses, and the surface area, volume and diame- ter of the pores were derived. It is found that the porous shell thickness and the pore size can be tuned by changing the coating times of silica nanoparticles. Finally, PS@SiO2 core-shell microbeads with 5 grn PS solid core and 350 nm mesoporous shell （mean BJH pore diameter is ~27 nm） were used to load CdSe/ZnS quantum dots （QDs）. The fluorescence microscopic image and the optical amplification of the QDs-embedded microbeads （QDBs） indicate that the as-prepared core-shell microbeads can provide adequate space for QDs and may be useful for further application of nano-micro composites.
基金Project(60537050) supported by the National Natural Science Foundation of China
文摘Polyelectrolyte/polyelectrolyte, organic molecule/colloidal CdS and polyelectrolyte/MWCNT films were fabricated via the layer-by-layer assembling technique. The assembled films were characterized by UV-vis spectrophotometer, X-ray diffractometry, nano profilometer and scanning electron microscopy. The results demonstrate that the layer-by-layer assembling technique can be used to make the nanoscaled films from polyelectrolytes and thicker composite films from suitable precursor materials. Both organic molecule/colloidal CdS films and PEI/MWCNT films with thickness of hundreds of nanometers were obtained. For the organic molecule/colloidal CdS films, a reasonable explanation for the result is that both the organic molecules and the CdS particles aggregate in the films. For the PEI/MWCNT films, obviously, it is the MWCNT that makes the great contribution to the film thickness.
基金The authors thank the support from the National Natural Science Foundation of China(Grant No.21676276).
文摘Polyelectrolyte-doped microcapsules(PDM)was fabricated by coaxial electrospray of a mixture of glycerol and water containing 10 mg/mL cationic polyelectrolyte poly(allylamine hydrochloride)(PAH)fed as the core phase solution,and a N,N-dimethylacetylamide solution of 10 wt%polyurethane fed as the shell phase solution.Multienzyme system involving Candida Antarctica lipase B(CALB),glucose oxidase(GOD),and horseradish peroxidase(HRP)for cascade reaction was assembled in the PDM at three different places,namely,surface,shell,and lumen.Placing of enzyme inside aqueous lumen of the PDM was realized by in situ encapsulation through adding the enzyme in the core-phase solution for coaxial electrospray.By ion-pairing of enzyme with cationic surfactant CTAB,an organic soluble enzyme-CTAB complex was prepared,so that in situ embedding of enzyme in the shell of the PDM was realized by adding it into the shell phase solution.Surface attachment of enzymes was achieved by layer-by-layer(LbL)technology,which is based on the ion-exchange interactions between oppositely charged enzymes and PAH that was doped in PDM.The enzyme-decorated microcapsule was then studied as a microbioreactor,in which 1-Oxododecyla-α-glucopyranoside was converted by CALB to glucose,which was oxidised by GOD to gluconolactone in a second step.The hydrogen peroxide produced was then used by HRP to oxidize ABTS to form coloured radical cation ABTS•+for activity analysis.The successful fabrication of the PDM and precise localization of enzymes in the PDM by different strategies were fully characterized.By varying the immobilization strategy,totally six PDM bioreactors with three enzymes precisely positional assembled in different strategies were constructed and their activities for the cascade reaction were investigated and compared.The PDM micro-bioreactor prepared by novel electrospray technologies provide a smart platform for positional assembly of multi-enzyme cascade reaction in a precise and well-controlled manner.
基金Project(2014TDJH104)supported by Shandong University of Science and Technology(SDUST)Research FundChina+3 种基金Project(2013RCJJ006)supported by Scientific Research Foundation of Shandong University of Science and Technology for Recruited TalentsChinaProject(BS2013CL009)supported by Scientific Research Foundation of Shandong for Outstanding Young ScientistChina
文摘To enhance the corrosion resistance of magnesium（Mg） alloy and to impart its surface with antibacterial functionality for inhibiting biofilm formation and biocorrosion, Mg（OH）2 films were fabricated on AZ31 magnesium alloy substrates by an in-situ hydrothermal method and well-defined multilayer coatings, consisting of gentamicin sulfate（GS） and poly（sodium 4-styrene sulfonate）（PSS）, were prepared via layer-by-layer（Lb L） assembly. The morphologies, chemical compositions and corrosion resistance of the obtained（PSS/GS）n/Mg sample were investigated using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, electrochemical methods and immersion tests. Finally, the bactericidal activity of（PSS/GS）n/Mg samples against Staphylococcus aureus was assessed by the zone of inhibition methods and plate-counting method. The so-synthesized composite coating on the Mg alloy substrates exhibits good corrosion resistance and antibacterial performance, which make them attractive as coatings for medical implanted devices.
基金supported by Shanghai Municipal Natural Science Foundation,China(No.21ZR1446800)the National Natural Science Foundation of China(No.41877425)the Fundamental Research Funds for the Central Universities(No.226-2024-00052)。
文摘Microorganisms can colonize the surface of microplastics(MPs)to form a distinctive microbiome,known as a“plastisphere”which is regarded as an anthropogenic niche for microbial growth.However,bacterial community assembly in virgin and aging MP plastispheres across different habitats is poorly understood.This study aims to assess the variations in bacterial community assembly across different niches and habitats with an in situ ex-periment,in which constructed forest wetland(FW),natural lake wetland(LW),and lotus pond wetland(LP)were habitats,and plastispheres of virgin and aging low-density polyethylene(LDPE)MPs,as well as surround-ing wetland soils were niches.Significant niche-related differences in bacterial communities were observed,with lower diversity and enrichment of potential plastic-degrading bacteria in the plastisphere than in the soil bacterial communities.Furthermore,habitat-related differences exerted a more pronounced influence on the beta-diversity patterns of the bacterial communities.The linear regression analyses indicated that the local species pool con-tributed more to bacterial community assembly in the LW wetland,whereas the relative abundance of species was the primary factor in the LP wetland.The null model analysis indicated that plastisphere bacterial communi-ties were predominantly driven by the stochastic process,with a more deterministic assembly observed in the LP wetland and soil bacterial communities.Additionally,the primary ecological process shaping plastisphere com-munities shifted from drift in the virgin LDPE to homogenising dispersal in the aging LDPE.This study provides new insights into the fate and ecological impacts of MPs in wetlands,thereby facilitating the effective regulations of plastic pollution.
基金supported by Key Laboratory of Cyberspace Security,Ministry of Education,China。
文摘Transformer-based models have significantly advanced binary code similarity detection(BCSD)by leveraging their semantic encoding capabilities for efficient function matching across diverse compilation settings.Although adversarial examples can strategically undermine the accuracy of BCSD models and protect critical code,existing techniques predominantly depend on inserting artificial instructions,which incur high computational costs and offer limited diversity of perturbations.To address these limitations,we propose AIMA,a novel gradient-guided assembly instruction relocation method.Our method decouples the detection model into tokenization,embedding,and encoding layers to enable efficient gradient computation.Since token IDs of instructions are discrete and nondifferentiable,we compute gradients in the continuous embedding space to evaluate the influence of each token.The most critical tokens are identified by calculating the L2 norm of their embedding gradients.We then establish a mapping between instructions and their corresponding tokens to aggregate token-level importance into instructionlevel significance.To maximize adversarial impact,a sliding window algorithm selects the most influential contiguous segments for relocation,ensuring optimal perturbation with minimal length.This approach efficiently locates critical code regions without expensive search operations.The selected segments are relocated outside their original function boundaries via a jump mechanism,which preserves runtime control flow and functionality while introducing“deletion”effects in the static instruction sequence.Extensive experiments show that AIMA reduces similarity scores by up to 35.8%in state-of-the-art BCSD models.When incorporated into training data,it also enhances model robustness,achieving a 5.9%improvement in AUROC.
基金supported by the National Natural Science Foundation of China(Grant No.52475543)Natural Science Foundation of Henan(Grant No.252300421101)+1 种基金Henan Province University Science and Technology Innovation Talent Support Plan(Grant No.24HASTIT048)Science and Technology Innovation Team Project of Zhengzhou University of Light Industry(Grant No.23XNKJTD0101).
文摘Aircraft assembly is characterized by stringent precedence constraints,limited resource availability,spatial restrictions,and a high degree of manual intervention.These factors lead to considerable variability in operator workloads and significantly increase the complexity of scheduling.To address this challenge,this study investigates the Aircraft Pulsating Assembly Line Scheduling Problem(APALSP)under skilled operator allocation,with the objective of minimizing assembly completion time.A mathematical model considering skilled operator allocation is developed,and a Q-Learning improved Particle Swarm Optimization algorithm(QLPSO)is proposed.In the algorithm design,a reverse scheduling strategy is adopted to effectively manage large-scale precedence constraints.Moreover,a reverse sequence encoding method is introduced to generate operation sequences,while a time decoding mechanism is employed to determine completion times.The problem is further reformulated as a Markov Decision Process(MDP)with explicitly defined state and action spaces.Within QLPSO,the Q-learning mechanism adaptively adjusts inertia weights and learning factors,thereby achieving a balance between exploration capability and convergence performance.To validate the effectiveness of the proposed approach,extensive computational experiments are conducted on benchmark instances of different scales,including small,medium,large,and ultra-large cases.The results demonstrate that QLPSO consistently delivers stable and high-quality solutions across all scenarios.In ultra-large-scale instances,it improves the best solution by 25.2%compared with the Genetic Algorithm(GA)and enhances the average solution by 16.9%over the Q-learning algorithm,showing clear advantages over the comparative methods.These findings not only confirm the effectiveness of the proposed algorithm but also provide valuable theoretical references and practical guidance for the intelligent scheduling optimization of aircraft pulsating assembly lines.
基金National Science and Technology Council,the Republic of China,under grants NSTC 113-2221-E-194-011-MY3 and Research Center on Artificial Intelligence and Sustainability,National Chung Cheng University under the research project grant titled“Generative Digital Twin System Design for Sustainable Smart City Development in Taiwan.
文摘Modern manufacturing processes have become more reliant on automation because of the accelerated transition from Industry 3.0 to Industry 4.0.Manual inspection of products on assembly lines remains inefficient,prone to errors and lacks consistency,emphasizing the need for a reliable and automated inspection system.Leveraging both object detection and image segmentation approaches,this research proposes a vision-based solution for the detection of various kinds of tools in the toolkit using deep learning(DL)models.Two Intel RealSense D455f depth cameras were arranged in a top down configuration to capture both RGB and depth images of the toolkits.After applying multiple constraints and enhancing them through preprocessing and augmentation,a dataset consisting of 3300 annotated RGB-D photos was generated.Several DL models were selected through a comprehensive assessment of mean Average Precision(mAP),precision-recall equilibrium,inference latency(target≥30 FPS),and computational burden,resulting in a preference for YOLO and Region-based Convolutional Neural Networks(R-CNN)variants over ViT-based models due to the latter’s increased latency and resource requirements.YOLOV5,YOLOV8,YOLOV11,Faster R-CNN,and Mask R-CNN were trained on the annotated dataset and evaluated using key performance metrics(Recall,Accuracy,F1-score,and Precision).YOLOV11 demonstrated balanced excellence with 93.0%precision,89.9%recall,and a 90.6%F1-score in object detection,as well as 96.9%precision,95.3%recall,and a 96.5%F1-score in instance segmentation with an average inference time of 25 ms per frame(≈40 FPS),demonstrating real-time performance.Leveraging these results,a YOLOV11-based windows application was successfully deployed in a real-time assembly line environment,where it accurately processed live video streams to detect and segment tools within toolkits,demonstrating its practical effectiveness in industrial automation.The application is capable of precisely measuring socket dimensions by utilising edge detection techniques on YOLOv11 segmentation masks,in addition to detection and segmentation.This makes it possible to do specification-level quality control right on the assembly line,which improves the ability to examine things in real time.The implementation is a big step forward for intelligent manufacturing in the Industry 4.0 paradigm.It provides a scalable,efficient,and accurate way to do automated inspection and dimensional verification activities.
基金supported by the National Key Research and Development Program of China(No.2021YFC2400703)the Key Scientific and Technological Research Projects in Henan Province(Nos.232102311155 and 232102230106)Zhengzhou University Major Project Cultivation Special Project(No.125-32214076).
文摘Drug-eluting magnesium(Mg)alloy stents have a slower degradation rate and lower restenosis rate compared with uncoated stents,demonstrating good clinical efficacy.However,the release of anti-hyperplasia drugs from coatings delays endothelial tissue repair,thus leading to late stent thrombosis.To address these issues,a dual self-healed coating with various biological properties was fabricated on magnesium fluoride/polydopamine(MgF_(2)/PDA)-treated Mg alloys by spraying-assisted layer-by-layer(LBL)self-assembly of chitosan(CS),gallic acid(GA),and 3-aminobenzeneboronic acid-modified hyaluronic acid(HA-ABBA).The LBL coating,approximately 1.50μm thick,exhibited a uniform morphology with good adhesion strength(~1065 mN).The annual corrosion rate(Pi)of LBL samples was~1400 times slower than that of the Mg substrate,due to the physical barrier function provided by MgF_(2)/PDA layers and the dual self-healed ability of LBL layers.The rapid self-healing ability(with a healing period of~4 h under dynamic/static conditions)resulted from the synergistic interplay between the recombination of diverse chemical bonds within the LBL coating and the coordination of LBL-released GA with Mg2+,as corroborated by computer simulations.Compared with the drug-eluting coatings,the LBL sample demonstrated substantial advantages in anti-oxidation,anti-denaturation of fibrinogen,anti-platelet adhesion,anti-inflammation,anti-hyperplasia,and promoted-endothelialization.These benefits effectively address the limitations associated with drug-eluting coatings.
基金supported by Rachadapisek Sompote Fund for Postdoctoral Fellowship, Chulalongkorn University, Thailandthe Nanotechnology Center (NANOTEC), NSTDA Ministry of Science and Technology, Thailand, through its program of Center of Excellence Network+1 种基金National Research University Project of CHEthe Rachadapisek Sompote Endowment Fund (No. AM1041A)
文摘Polypropylene（PP） meltblown fibers were coated with titanium dioxide（Ti O2） nanoparticles using layer-by-layer（Lb L） deposition technique. The fibers were first modified with 3layers of poly（4-styrenesulfonic acid）（PSS） and poly（diallyl-dimethylammonium chloride）（PDADMAC） to improve the anchoring of the Ti O2 nanoparticle clusters. PDADMAC, which is positively charged, was then used as counter polyelectrolyte in tandem with anionic Ti O2 nanoparticles to construct Ti O2/PDADMAC bilayer in the Lb L fashion. The number of deposited Ti O2/PDADMAC layers was varied from 1 to 7 bilayer, and could be used to adjust Ti O2 loading. The Lb L technique showed higher Ti O2 loading efficiency than the impregnation approach. The modified fibers were tested for their photocatalytic activity against a model dye, Methylene Blue（MB）. Results showed that the Ti O2 modified fibers exhibited excellent photocatalytic activity efficiency similar to that of Ti O2 powder dispersed in solution. The deposition of Ti O23 bilayer on the PP substrate was sufficient to produce nanocomposite fibers that could bleach the MB solution in less than 4 hr.Ti O2-Lb L constructions also preserved Ti O2 adhesion on substrate surface after 1 cycle of photocatalytic test. Successive photocatalytic test showed decline in MB reduction rate with loss of Ti O2 particles from the substrate outer surface. However, even in the third cycle, the Ti O2 modified fibers are still moderately effective as it could remove more than 95% of MB after 8 hr of treatment.
