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To address the technical bottleneck of synergistic damage caused by corrosion and scaling after damage to protective coatings on heat exchangers, petrochemical pipelines, and seawater desalination equipment, the surface scaling amount and calcium carbonate crystal morphology of anti-corrosion polymer coating (expressed as ZF,WCA = 95°) and self-cleaning coating (expressed as ZQ,WCA = 120°, WSA = 14°) are compared in a scaling system involving metal ions (Fe2+) generated by corrosion. The anti-scaling effect of the ZQ coating (34.6 %) with ions is 61.7 % higher than that of the ZF coating (21.4 %). As the concentration of Fe2+ increases, the aragonite on the ZQ coating transform from needle shaped crystals to cactus shaped crystals (expressed as C-CaCO 3) with their whisker length about 20 μm. Furthermore, Cu2+ is introduced into the system by galvanic corrosion between steel and copper. The crystals on the ZQ coating are honeycomb shaped calcite, which transform to C-CaCO 3 with shorter whisker length about 10 μm as the contacting area of steel/copper galvanic couple increases. The C-CaCO 3 reduces the adhesive area of crystals on the surface of self-cleaning coatings with low surface energy, making it easier to be removed in dynamic scaling environment. Therefore, a self-cleaning coating on copper for inhibiting CaCO 3 crystallization and scaling was prepared, hoping to provide a new method for the crystallization of multiple ions on the surface of self-cleaning coatings in the field of engineering scale prevention. [ABSTRACT FROM AUTHOR]

In view of the technology bottleneck of the adhesion failure of traditional functional protective coatings on the smoother surface of precise parts served in the marine atmosphere, a room-temperature-curable fluoropolymer/polyurethane (denoted as RFP) polymer composite coating of 20–30 μm is prepared on the metal substrates. Static pull-off and dynamic friction test methods are used to evaluate the interface adhesion of the coating. The coating shows superior adhesive strength of 18–24 MPa on a variety of metal substrates with a wide range of surface roughness (Ra = 0.1–1.6 μm). The friction coefficient of the coating surface is about 0.05–0.08, and the wear life is up to 9–12 km/μm. Furthermore, the adhesion strength of the coating remains 12–14 MPa after 1600 h of salt spray while the wear life of the coating keeps 3–9 km/μm after 720 h of salt spray. The influences of surface roughness (R a) , surface free energy (γ O x i d e ), surface potential (φ O x i d e) of the metal substrates and the bonding force at substrate-coating interface on the adhesive energy (E a d h.) are discussed, and the mechanism of "physical-chemical-surface" synergetic enhanced interface adhesion is proposed. The RFP coating is used as the intermediate layer for traditional PU and EP coatings to improve their adhesion on smooth aluminum substrate from 1.39 MPa to 17.5 MPa (increased by 1260 %). Thus, the polymer coating has the potential to provide technical support for the development of long-term anticorrosive coating technology for precision components of marine high-tech equipment. • The RFP polymer coating showed adhesive strength of 18-24 MPa on metals with surface roughness (Ra) about 0.1-1.6 μm. • Static pull-off and dynamic friction tests were integrated to evaluate the interface adhesion and reveal its mechanism. • The adhesion remained 12-14 MPa after 1600 h of salt spray and the wear life reached 3-9 km/μm after 720 h of salt spray. • Ra , γ O x i d e , φ O x i d e E a d h. .A mechanism of "physical-chemical-surface" synergetic enhanced interface adhesion has been innovatively proposed. • The RFP coating shows promise in addressing adhesion for functional coatings on smoother substrates or primers. [ABSTRACT FROM AUTHOR]

Purpose: Reducing X‐ray dose increases safety in cardiac electrophysiology procedures but also increases image noise and artifacts which may affect the discernibility of devices and anatomical cues. Previous denoising methods based on convolutional neural networks (CNNs) have shown improvements in the quality of low‐dose X‐ray fluoroscopy images but may compromise clinically important details required by cardiologists. Methods: In order to obtain denoised X‐ray fluoroscopy images whilst preserving details, we propose a novel deep‐learning‐based denoising framework, namely edge‐enhancement densenet (EEDN), in which an attention‐awareness edge‐enhancement module is designed to increase edge sharpness. In this framework, a CNN‐based denoiser is first used to generate an initial denoising result. Contours representing edge information are then extracted using an attention block and a group of interacted ultra‐dense blocks for edge feature representation. Finally, the initial denoising result and enhanced edges are combined to generate the final X‐ray image. The proposed denoising framework was tested on a total of 3262 clinical images taken from 100 low‐dose X‐ray sequences acquired from 20 patients. The performance was assessed by pairwise voting from five cardiologists as well as quantitative indicators. Furthermore, we evaluated our technique's effect on catheter detection using 416 images containing coronary sinus catheters in order to examine its influence as a pre‐processing tool. Results: The average signal‐to‐noise ratio of X‐ray images denoised with EEDN was 24.5, which was 2.2 times higher than that of the original images. The accuracy of catheter detection from EEDN denoised sequences showed no significant difference compared with their original counterparts. Moreover, EEDN received the highest average votes in our clinician assessment when compared to our existing technique and the original images. Conclusion: The proposed deep learning‐based framework shows promising capability for denoising interventional X‐ray fluoroscopy images. The results from the catheter detection show that the network does not affect the results of such an algorithm when used as a pre‐processing step. The extensive qualitative and quantitative evaluations suggest that the network may be of benefit to reduce radiation dose when applied in real time in the catheter laboratory. [ABSTRACT FROM AUTHOR]

Reducing radiation dose in cardiac catheter-based X-ray procedures increases safety but also image noise and artifacts. Excessive noise and artifacts can compromise vital image information, which can affect clinical decision-making. Developing more effective X-ray denoising methodologies will be beneficial to both patients and healthcare professionals by allowing imaging at lower radiation dose without compromising image information. This paper proposes a framework based on a convolutional neural network (CNN), namely Ultra-Dense Denoising Network (UDDN), for low-dose X-ray image denoising. To promote feature extraction, we designed a novel residual block which establishes a solid correlation among multiple-path neural units via abundant cross connections in its representation enhancement section. Experiments on synthetic additive noise X-ray data show that the UDDN achieves statistically significant higher peak signal-to-noise ratio (PSNR) and structural similarity index measure (SSIM) than other comparative methods. We enhanced the clinical adaptability of our framework by training using normally-distributed noise and tested on clinical data taken from procedures at St. Thomas’ hospital in London. The performance was assessed by using local SNR and by clinical voting using ten cardiologists. The results show that the UDDN outperforms the other comparative methods and is a promising solution to this challenging but clinically impactful task. [ABSTRACT FROM AUTHOR]

Two colloidal suspensions of paucidisperse, spherical silica particles with different surface chemistries leading to extreme limits of surface contact friction are studied to identify experimental differences in shear rheology and microstructure and quantitatively test theory and simulation models. The nonequilibrium microstructure in the plane of shear is measured by flow-small angle neutron scattering for steady shear states spanning the shear thinning and shear thickening regimes. The shear rheology and microstructure are compared against predictions from theory for Brownian hard sphere suspensions and state-of-the-art simulation methods that incorporate either contact friction or enhanced lubrication hydrodynamics. The first normal stress differences are confirmed to distinguish between these micromechanical mechanisms for stress enhancement in the shear thickened regime. The nonequilibrium microstructure in the plane of shear shows more anisotropy for the suspension with higher interparticle friction. A significant fourfold symmetry is confirmed and found to be amplified with increasing surface contact friction in the shear thickened state. The differences in shear-induced microstructures between suspensions with varying contact friction demonstrate that the nonequilibrium microstructure can distinguish between nanotribological interactions in the shear thickened state. Statistical comparison of experiments with simulations indicates that better resolution of microstructures in simulation models is required to be validated by the experimental data presented. Implications for the development of theories for colloidal suspension rheology are discussed. [ABSTRACT FROM AUTHOR]

Dense colloidal suspensions are processed in a wide variety of industries. Challenges for pumping suspensions and slurries at high concentrations include shear thickening and dilation, which can have deleterious consequences. These systems are shear sensitive close to the jamming point, meaning that a significant increase in high shear viscosity can be observed with just a few percent change in volume fractions. Therefore, accurate and rapid determination of the jamming point can greatly aid formulation. Typically, conventional rheometry identifies the jamming point by a time-consuming process, whereby multiple flow curves of suspensions of different volume fraction are measured and extrapolated to the volume fraction where the viscosity diverges. We present an alternative approach for rapid, one-step, experimental determination of the jamming point for aqueous suspensions. The procedure monitors the shear stress under constant shear stress or shear rate as the sample is dewatered using immobilization cell rheometry, until the viscosity diverges. The method is validated by comparing the results of this work with conventional rheometry for a model suspension. Then it is applied to examine the effect of grafting a short-chain polymer to particles, comprising an industrial suspension of silica-coated titania. Polymeric coating of the particles increases the jamming concentration and mitigates shear thickening, qualitatively consistent with predictions from simulations. [ABSTRACT FROM AUTHOR]

Rheological experiments on model and industrial colloidal dispersions that exhibit reversible shear thickening are compared to a recent model that correlates simulation results for the shear rheology of bidisperse suspensions of particles with varying levels of contact friction. Comparisons are presented with rheological results for a variety of colloidal dispersions varying from model systems to industrially relevant, commercial dispersions where both shear and first normal stress differences are available. Particle-scale measurements of particle friction coefficients are provided through a survey of the literature. The comparisons show under which conditions the model can quantitatively describe the measured rheology and how the model can be used to correlate data for systems with more complex interactions when allowances are made for effective volume fractions and adjustments in friction coefficients. Discrepancies evident in comparisons for the first normal stress differences highlight the importance of enhanced hydrodynamic friction in many systems, especially for continuous shear thickening, in qualitative agreement with recent simulations that incorporate enhanced lubrication hydrodynamics due to elastohydrodynamics or particle roughness. Finally, a literature survey of measurements of jamming volume fractions and particle friction coefficients indicates that the model overestimates the experimentally observed jamming volume fraction. The comparisons presented in this work provide quantitative information valuable for those modeling suspension processing as well as suggestions for further model improvement. [ABSTRACT FROM AUTHOR]

To investigate the variations in price volatility spillover effects on different time scales across the LME, SMM, and Chinese spot nickel markets. This study uses data from the London Metal Exchange (LME), Shanghai Nonferrous Metals (SMM) nickel daily closing prices, and Chinese nickel daily market prices from April 1, 2015, to September 30, 2022, to categorize the above three markets' yield series into four-time scales: very short, short, medium, and long term. The multivariate BEKK-GARCH approach is then used to analyze the spillover effects at different time scales. The study's findings reveal that (1) the LME, SMM, and spot nickel prices are all impacted by external shocks and inherent volatility at all time scales; (2) at the very short time scale, there is a two-way volatility spillover effect between the SMM nickel and the other two markets, in addition, a one-way volatility spillover effect between the LME and spot nickel price; (3) at the short time scale, the volatility spillover effect between the LME and spot nickel price disappears; (4) at the medium-term time scale, there is no volatility spillover effect between the LME, SMM, and spot nickel price; (5) at the long-term time scale, the SMM has a volatility spillover effect on spot nickel price. [ABSTRACT FROM AUTHOR]

At present, mechanical de-rust technologies (grinding and sandblasting) are forbidden in some specific engineering fields such as oil drilling platforms equipped with storage tanks, chemical pipelines and power transmission system. It is passivated rust with cracks and holes that is known to hinder adhesion between anticorrosive coating and metallic substrate. This paper reported an organic-organic fluoropolymer/polyurethane (PF/PU) polymer coating, showing strong adhesion strength of 18.2 MPa with rust and 16.5 MPa after 240 h salt spray test, which is 2–3 times higher than conventional inorganic-organic epoxy (EP) coating (6–9 MPa). The PF/PU coating have protected rusted chemical pipelines from marine atmosphere corrosion for 3 years. Due to the micro/nano-channels in the rust layer, PF/PU precursor of appropriate surface tension and viscosity spontaneously adsorb/adhesive, wet, spread and fill with the channel by capillary force. A composite polymer-rust‑iron substrate with three-dimensional interpenetrating network is fabricated via mechanical interlocking/chemical bonding and PU cross-linking. The physical model of "capillary filling of polymer coating in micro/nano-rust-channels (μ/nRCs)" is proposed and demonstrated by "spinning by air cushion escaping" phenomenon as one end of the channel sealed. Based on researches and practical engineering applications on chemical pipelines and subway/railway tracks, a new polymer coating technology with rust towards on-site maintenance has been developed, aiming to realize the surface function remanufacturing of high-tech equipment served in severe corrosive medium and improve reliability of the equipment. [Display omitted] • A PF/PU polymer coating was designed to fabricate a polymer-rust‑iron with three-dimensional interpenetrating network. • The PF/PU coating with rust showed strong adhesion strength of 18.2 MPa, even 16.5 MPa after exposed to salt spray for 240 h. • A physical model of "capillary filling of polymer coating in micro/nano-rust-channels (μ/nRCs)" is proposed. • "Spinning by air cushion escaping" phenomenon is found at the rust-coating interface with the channel outlets sealed. • Based on engineering applications, a new polymer-coating-technology with rust towards on-site maintenance has been developed. [ABSTRACT FROM AUTHOR]

[Display omitted] • An MP@PDA- E. coli -based colorimetric method was developed to detect L-Trp. • The method exhibited excellent chiral selectivity for L-Trp. • The method was successfully applied to detect L-Trp in millets. • The detection of percentage of L-Trp in the enantiomeric mixture can be realized. • A potable device was fabricated to make detecting L-Trp more convenient. Chiral recognition of enantiomers has always been a thorny issue since they exhibit the same properties under an achiral environment. Herein, polydopamine-functionalized magnetic particles (MP@PDA) were synthesized to immobilize the genetically engineered bacterium Escherichia coli DH5α (MP@PDA- E. coli). L-tryptophan (Trp) instead of D-Trp can be stereo-specifically degraded by tryptophanase in E. coli. The degradation product indole reacts with 4-dimethylaminobenzaldehyde to generate a rose-red adduct. Thus, MP@PDA- E. coli was employed to fabricate a chiral colorimetric method for chiral recognition and determination of L-Trp. The method averts the purification of tryptophanase. More importantly, tryptophanase demonstrates excellent enantioselective ability for L-Trp. The method can not only quantitatively detect L-Trp but also realize the measurement of the enantiomer percentage in the enantiomeric mixture. The feasibility was verified by detecting L-Trp in millet samples from different origins. Furthermore, a portable device was fabricated to make the method more convenient. [ABSTRACT FROM AUTHOR]

With coupled mechanical-chemical field, the predominant role of fatigue crack evolution and tribo-chemistry on Si-DLC films were investigated under different relative humidity. Results show that incorporating Si stabilized friction interface and induced lubricating carbonaceous material transfer (0.053 under 20% RH), but the lubricating effect was deteriorated (0.12) by the iron oxide products on sliding shear stress. Furthermore, Si element aggravate overall wear rates than DLC film. Increasing relative humidity was beneficial to lowering wear rates of films with lower Si content, but aggravated the wear rates of films with higher Si content. The predominant role of tribo-chemistry on the friction coefficient (COF) was confirmed, meanwhile, critical impact of fatigue cracks evolution on surface wear is worse than that of tribo-chemistry. • Incorporating Si induced lubricating carbonaceous transfer, but the iron oxide products deteriorated lubricating effect. • Increasing relative humidity reduced wear rates of lower Si films, but aggravated the wear rates of higher Si films. • The fatigue cracks evolution of Si-DLC films was consistent with the increasing wear rates of Si-DLC films. [ABSTRACT FROM AUTHOR]

ABSTRACT Well-defined 1,4-diketo-3,6-di(thiophen-2-yl)pyrrolo[3,4-c]pyrrole (DTDPP) labeled polycaprolactones (PCL) with different chain lengths were synthesized and characterized. The effect of polymer chain lengths on the optical properties of DTDPP in solid states was studied by UV-Vis absorption spectroscopy as well as steady-state and dynamic fluorescence spectroscopies. Our results indicate that when the PCL side chain is extended to a certain length, the intermolecular aggregation of DTDPP units can be reduced significantly due to segregation effect of PCL. This approach offers a new facile strategy to address the common problem of aggregation-caused quenching existing in organic fluorophores. These highly fluorescent biodegradable PCL polymers may find broad biomedical applications such as fluorescence-based bioimaging and tissue engineering. © 2015 Wiley Periodicals, Inc. J. Polym. Sci. Part A: Polym. Chem. 2015, 53, 1032-1042 [ABSTRACT FROM AUTHOR]

To study the influence of different laws of guide vane angle on the performance of reactor coolant pump (RCP), five models of RCP with different guide vane were designed, and the three‐dimensional numerical calculation was carried out. Based on the entropy production theory, analysis of flow loss at part‐load, design, and the over‐load flow rate was investigated. The results show that under the design flow and over‐load flow condition, the head, and efficiency of the DY4 (RCP model of the fourth guide vane variation) model are the highest, and the best efficiency occurs at the design flow rate. Compared with the DY1 (RCP model of the first guide vane variation) model, the efficiency of RCP is increased by 3.68%. At design flow and over‐load flow, the distribution of pressure and velocity streamlines of the DY4 model pump is uniform and stable, the flow loss ratio in the guide vane and volute is the lowest, and the high‐value area is small. Under the condition of part‐load flow rate, the pump head and efficiency of DY5 (RCP model of the fifth guide vane variation) model are the highest, and the highest efficiency appears at 0.8Qd which is 1.69% higher than the best efficiency value of DY4. At the part‐load flow rate, the static pressure values in the guide vane and volute of the DY5 model pump are significantly higher than that of other models. The velocity change in the flow channel is uniform, and the flow loss in the guide vane and volute is the lowest. Compared with the part‐load flow rate condition, the hydraulic performance of the DY5 model pump under design flow rate and over‐load flow condition is lower than that of other models. [ABSTRACT FROM AUTHOR]

In order to study the influence of different guide vane angle variation on performance characteristics of reactor coolant pump (RCP) during idling process, the external characteristics of RCP model with five different guide vane angles at idling process state were analyzed. Radial force characteristics and blade load characteristics of RCP were analyzed. The results show that the head and torque changes of pump with different guide vane angles in different idle period are consistent. The head of DY1model (Guide vane angle increases sharply first and then decreases gently, which convexity is large) is the highest and torque is small. The head drop rate of DY5 model (Guide vane decreases first and then increases, and the concavity is large) is the highest and torque is the largest. With the idling, the radial force of impeller and guide vane decreases gradually. The radial force of DY5 model impeller is small and the fluctuation range is weak. The radial force of DY4 model (Guide vane shows concavity change with gentle increase) impeller before idling is the largest. In the nonlinear transition of idle period, the total radial force of DY4 model is 235 N when idling for 32 s, which is nearly 30 times lower than that before idling, and the radial force decreases the most. In different idling periods, the radial force amplitude of guide vane of DY5 model is the largest, and the radial force decrease amplitude of guide vane of DY4 model is the largest in the whole idling period. The impeller blade load of DY4 and DY5 model pumps with concavity guide vane angle change law is significantly higher than that of other model pumps after the relative position of streamline is 0.6. When the relative position of the guide vane along the streamline direction is less than 0.5, the load fluctuation of the guide vane of each model pump is large. When the relative position is greater than 0.5, the blade load fluctuation is relatively small. [ABSTRACT FROM AUTHOR]

Rapid screening of bacteria by low-cost and eco-friendly material-based approaches is still a major challenge. Herein, a colorimetric biosensor was designed for the ultrasensitive and rapid detection of Gram-positive bacteria. The biosensor exploited polydopamine and polyethyleneimine (PDA-PEI)-modified papers for separating bacteria and carbon dots (CDs) for selective colorimetric detection of Gram-positive bacteria. Noble metal-free CDs can target Gram-positive bacteria by binding with peptidoglycan and possess peroxidase-like activity. Thus, they can avert the step of modifying recognition probes, facilitating biosensor fabrication, and reducing the cost. This biosensor can detect S. aureus as low as 1 cfu mL−1, L. monocytogenes as low as 5 cfu mL−1, and B. subtilis as low as 9 cfu mL−1 within 55 min. In addition, a portable device was constructed to enable convenient and on-site quantitative detection of Gram-positive bacteria. The feasibility of the biosensor was verified by detecting Gram-positive bacteria in eggshell and sausage samples with recoveries ranging from 91.2% to 110%. [Display omitted] • A colorimetric biosensor was developed based on PDA-PEI@paper and CDs. • The biosensor can selectively detect Gram-positive bacteria. • PDA-PEI@paper can enrich bacteria to improve sensitivity. • CDs with peroxidase-like activity can target Gram-positive bacteria. • The LODs of the biosensor for Gram-positive bacteria were less than 10 cfu mL−1. [ABSTRACT FROM AUTHOR]

We study colloids suspended in nematic liquid crystal in grooves with homeotropic anchoring. We observe "eyelashes", topological dipole chains that follow the local, curved director field. These beget wires that connect the groove corners to topographical features on the cell lid to yield oriented, curvilinear colloidal wires spanning the cell, formed in a nonsingular director field. As the groove aspect ratio changes, we find different ground states and corroborate our observation with numerics. Our results rely upon on the scale of topographical features, the sharpness of edges, and the colloid-sourced distortions; all these elements can be exploited to guide the formation of reconfigurable structures in nematics. [ABSTRACT FROM AUTHOR]

Physically intelligent micro‐robotic systems exploit information embedded in micro‐robots, their colloidal cargo, and their milieu to interact, assemble, and form functional structures. Nonlinear anisotropic fluids such as nematic liquid crystals (NLCs) provide untapped opportunities to embed interactions via their topological defects, complex elastic responses, and ability to dramatically restructure in dynamic settings. Here a four‐armed ferromagnetic micro‐robot is designed and fabricated to embed and dynamically reconfigure information in the nematic director field, generating a suite of physical interactions for cargo manipulation. The micro‐robot shape and surface chemistry are designed to generate a nemato‐elastic energy landscape in the domain that defines multiple modes of emergent, bottom‐up interactions with passive colloids. Micro‐robot rotation expands the ability to sculpt interactions; the energy landscape around a rotating micro‐robot is dynamically reconfigured by complex far‐from‐equilibrium dynamics of the micro‐robot's companion topological defect. These defect dynamics allow transient information to be programmed into the domain and exploited. Robust micro‐robotic manipulation strategies are demonstrated that exploit these diverse modes of nemato‐elastic interaction to achieve cargo docking, transport, release, and assembly of complex reconfigurable structures at multi‐stable sites. Such structures are of great interest to future developments of LC‐based advanced optical device and micro‐manufacturing in anisotropic environments. [ABSTRACT FROM AUTHOR]

Sargassum fusiforme residue (SFR) was ground by superfine grinding and regular grinding, the physical properties of powders were investigated. Superfine grinding SFR powder, with a mean particle size of 10.42 μm, showed higher water solubility index, soluble dietary fiber content, and total phenolic content compared with regular grinding SFR powder. Different levels (5%, 10%, 15%) of both kinds of SFR powders were added as flour replacement to make sponge cakes, their effects on the textural properties and sensory evaluation of cakes were studied. Cake batter density and viscosity, as well as sponge cake hardness and chewiness, were increased as the SFR powder amounts increased. Cakes contained regular grinding SFR powder showed higher hardness and chewiness than cakes contained superfine grinding SFR powder in general. The sensory evaluation results showed that cake with 10% superfine grinding SFR powder had the highest acceptability score. • Superfine grinding increased soluble dietary fiber and total phenolic content. • S. fusiforme residue powder increased hardness and chewiness of sponge cakes. • Cakes with 10% superfine grinding S. fusiforme residue powder was most acceptable. • S. fusiforme residue powder can be used for dietary fiber enrichment of cakes. [ABSTRACT FROM AUTHOR]

Both mesenchymal stromal cells (MSCs) and myeloid-derived suppressor cells (MDSCs) have immunosuppressive properties, and their presence may confer a worse prognosis upon cancer patients. However, whether MSCs can enhance the immunosuppressive effects of MDSCs in MM remains unknown. We evaluated the influence of MSCs on MDSCs growth, apoptosis, and functions. Our results show that MSCs promote proliferation and inhibit apoptosis in MDSCs. Additionally, MSCs enhance the ability of MDSCs by inhibiting T-cell proliferation and IFN-γ production. Furthermore, both the mRNA and protein levels of Arg1 and NOS2 were upregulated in MDSCs. These results suggest that MSCs may exert immunomodulatory effects on MDSCs by upregulating Arg1 and NOS2. [ABSTRACT FROM AUTHOR]

Nitrogen ion implantation and AlN/MoS 2 –phenolic resin duplex coating are designed to improve wear and corrosion resistance of magnesium alloys. The microstructure and tribocorrosion behaviors of as-fabricated coatings are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), tribocorrosion and electrochemical tests. Studies show that Cl ions induce severe corrosion degradation of magnesium alloy during the tribocorrosion test. MoS 2 –phenolic resin coating has two phase composite structure consisting of MoS 2 crystalline and phenolic resin, but this coating shows poor tribocorrosion resistance because force–corrosion synergy interaction accelerates the degradation process. The introduction of nitrogen ion implantation and AlN interlayer remarkably retards the corrosion degradation process of magnesium alloy. AlN/MoS 2 –phenolic resin duplex coating exhibits better tribocorrosion resistance. These present results indicating that gradient duplex coating might be a good candidate as protective coating in engineering applications of magnesium alloys. [ABSTRACT FROM AUTHOR]

Surface behaviors of superhydrophobic polymer coating applied in severe engineering environment are firstly systematically investigated. The PTFE/PPS (Polytetrafluoroethylene/Polyphenylene sulfide) coating still possess good superhydrophobicity after natural ice and snow covering for 10 day due to its micrometer-nanometer-scale binary structure (MNBS) with long-term stability. Scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and water contact angle (WCA) are used to characterize the morphology, chemical components and wetting properties of the coating, respectively. Surprisingly, the PTFE nano-fibers on most micro-scale papillae of the original coating were 'chemical-etched' and then 'secondary-constructed' to form nano-spheres/papules by HSO under 'accelerated simulated acid rain' condition (pH = 0.3). It is firstly found that chemical-etching by simulated acid rain only result in the 'secondary-construction' of MNBS structure. However, the laboratory weathering tests indicated that light-etching by the light with specified wavelength (UV, about 300-400 nm) can lead to both the 'secondary-construction' of MNBS structure and the change of surface chemical composition/groups on the superhydrophobic coatings. This thesis clarifies the long-term stability and surface behaviors of the superhydrophobic polymer coating under severe engineering condition, and will provide significant theoretical guidance for superhydrophobic polymer coating as anti-ice/frost engineering material. [ABSTRACT FROM AUTHOR]

A novel ion implantation and Al/AlN/CrAlN/CrN/MoS2 gradient duplex coating was used to improve the wear-corrosion synergy performance of AM60 magnesium alloy. The wear and corrosion behaviors of the as-deposited gradient duplex coating were subsequently investigated. The results showed that the gradient duplex coating has excellent wear resistance with the wear rate of 2.31 × 10−6 mm3/Nm, which is far below compared to that of the uncoated magnesium alloy of about 3.15 × 10−4 mm3/Nm. The introduction of intermediate layers between the top MoS2 layer and magnesium alloy substrate remarkably improved the magnesium alloy's load bearing capacity. The hardness and modulus of the Al/AlN/CrAlN/CrN intermediate layer was 20 and 7 times larger than that of the uncoated magnesium alloy, respectively. In addition, the corrosion resistance of the magnesium alloy with the gradient duplex coating was also enhanced with the corrosion current density, which decreased from 1.25 × 10−5 A/cm2 to 6.19 × 10−7 A/cm2. The present work provided a feasible strategy to fabricate wear-corrosion resistant coating via component and structure gradient design. [ABSTRACT FROM AUTHOR]