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With the continuous service time, long-span track cable-stayed bridges are inevitably affected by material time-varying and fatigue load periodic effects, and permanent down-deflection phenomenon is inevitable. The down-deflection of the main girder would lead to the irregularity of bridge deck, which would directly affect the running comfort and safety of the train. The permanent deformation control value should be set reasonably. In this paper, based on the research and analysis of domestic and foreign codes and standards, the evaluation criteria for the service performance of long-span track cable-stayed bridges was determined, aiming at the problem of deformation classification control in the service stage of the long-span track cable-stayed bridge. The limit of permanent deformation of main girder was analyzed, and the decision processing was put forward and applied to an engineering example. According to the vehicle-bridge coupling vibration analysis, the maximum vertical deformation safety control value in the service stage is L/400, and the pre-warning control value is L/500. With the non-permanent deformation value β deducted, the permanent deformation safety control value is L/400- β, and the pre-warning control value is L/500- β. The rationality of the grading control limit of permanent deformation based on service performance analysis has been verified by application analysis. [ABSTRACT FROM AUTHOR]

The double glow plasma surface alloying process (DGP) is an emerging alternative technology for fabricating thermal barrier coating. In spite of its merits such as gradient metallurgical bond and thickness controllability, DGP method is less well known than electron beam-physical vapour deposition and plasma spraying technique for the bond coatings. This paper serves as a preliminary study into the use of this technology for preparation of gradient MCrAlY bond coating on titanium alloys, with a focus on the oxidation performance at 750, 850 and 950°C. In this study, a gradient MCrAlY bond coating was successfully synthesised on γ-TiAl alloy by DGP. The as-deposited coating was composed of γ′-Ni3Al, γ-TiAl, AlCr2 and σ-NiCoCr. The maximum load that the as-deposited coating could bear was 60 N. The MCrAlY coating exhibited much better oxidation resistance than the bare TiAl alloy due to the formation of multilayer oxide scales. The research opportunities for further optimisation of this type of MCrAlY coatings are also discussed. [ABSTRACT FROM AUTHOR]

The effect of water-based aluminum phosphate (WAP) coating on the fatigue performance of 300 M steel with coating of primer and finishing layers was studied in the manuscript. The S-N curves showed that the WAP coating could improve the fatigue performance of the 300 M steel. The hydrogen embrittlement test showed that the WAP coating had no effect on the hydrogen embrittlement of the substrate and the uncoated specimens were very sensitive to air corrosion. The results of SEM, XRD, TEM, and nano-indentation tests showed that the finishing layer had excellent surface quality and high anti-damage ability, and the primer layer was loose and porous. However, the primer layer had obvious improving effect on the fatigue performance of the 300 M steel. It was due to the rapid reaction between the substrate and the coating, which improved the surface state of the substrate. [ABSTRACT FROM AUTHOR]

In order to analyze the influence of the stiffness change of the long-span track bridge on running safety of the train, a bridge and train analysis model, based on Chongqing Egongyan track bridge, is established to simulate and evaluate the spatial coupling dynamic response of the wind–train–bridge system through stiffness change and to propose the reasonable stiffness limit range of the long-span track suspension bridge. The results show that the dynamic characteristics of the bridge are good, and the safety of train operation and ride comfort meet the requirements when the vertical stiffness is 1/300–1/500 and the lateral stiffness is 1/600–1/1200; the dynamic response of the bridge and the running safety of the train are significantly sensitive to the stiffness change of the bridge, especially when the wind speed is 25 m/s and the vertical stiffness is 1/300, at this time, the derailment coefficient and the wheel load reduction rate reach 0.72 and 0.54, respectively, which are close to the limit standard, indicating that there are some potential safety hazards in train operation. [ABSTRACT FROM AUTHOR]

Maintaining the s-polarization state of laser beams is important to achieve high modulation depth in a laser-interference-based super-resolution structured illumination microscope (SR-SIM). However, the imperfect optical components can depolarize the laser beams hence degenerating the modulation depth. Here, we first presented a direct measurement method designed to estimate the modulation depth more precisely by shifting illumination patterns with equal phase steps. This measurement method greatly reduces the dependence of modulation depths on the samples, and then developed a polarization optimization method to achieve high modulation depth at all orientations by actively and quantitatively compensating for the additional phase difference using a combination of waveplate and a liquid crystal variable retarder (LCVR). Experimental results demonstrate that our method can achieve illumination patterns with modulation depth higher than 0.94 at three orientations with only one LCVR voltage, which enables isotropic resolution improvement. [ABSTRACT FROM AUTHOR]

To enhance the ablation resistance of graphite, double-glow plasma surface metallurgy technology was used to efficiently prepare Ta, TaC and Ta/TaC coatings on the graphite. All coatings exhibited a uniform and dense structure, with no microdefects at the interfaces, and the phases of the coatings closely matched the targets. The introduction of the Ta transition layer did not significantly improve the hardness or micro scratch performance of the Ta/TaC coating but greatly enhanced the toughness. Severe ablation occurred on the graphite substrate at 26.5 kW/cm2, while noticeable signs of ablation on the Ta and the two TaC coatings was at 61.9 kW/cm2 and 70.7 kW/cm2, respectively. Although the Ta transition layer did not enhance the ultimate failure power of the Ta/TaC coating, notably, the TaC coating lost its protective function after 10 cycles, whereas the Ta/TaC coating remained protective for 15 cycles, exhibiting superior resistance to cyclic ablation. This can be attributed to the Ta transition layer, which not only prevented crack formation and spalling of the Ta/TaC coating but also maintained the integrity of the coating by flowing and filling the TaC coating. Additionally, the Ta oxides formed during the early cycles also provided a certain degree of protection during subsequent ablation tests. The findings of this study can provide an effective approach for the design and fabricating technology of graphite ablation-resistant coatings.Graphical abstract: To enhance the ablation resistance of graphite, double-glow plasma surface metallurgy technology was used to efficiently prepare Ta, TaC and Ta/TaC coatings on the graphite. All coatings exhibited a uniform and dense structure, with no microdefects at the interfaces, and the phases of the coatings closely matched the targets. The introduction of the Ta transition layer did not significantly improve the hardness or micro scratch performance of the Ta/TaC coating but greatly enhanced the toughness. Severe ablation occurred on the graphite substrate at 26.5 kW/cm2, while noticeable signs of ablation on the Ta and the two TaC coatings was at 61.9 kW/cm2 and 70.7 kW/cm2, respectively. Although the Ta transition layer did not enhance the ultimate failure power of the Ta/TaC coating, notably, the TaC coating lost its protective function after 10 cycles, whereas the Ta/TaC coating remained protective for 15 cycles, exhibiting superior resistance to cyclic ablation. This can be attributed to the Ta transition layer, which not only prevented crack formation and spalling of the Ta/TaC coating but also maintained the integrity of the coating by flowing and filling the TaC coating. Additionally, the Ta oxides formed during the early cycles also provided a certain degree of protection during subsequent ablation tests. The findings of this study can provide an effective approach for the design and fabricating technology of graphite ablation-resistant coatings. [ABSTRACT FROM AUTHOR]

Photochromic hydrogels have promising prospects in areas such as wearable device, information encryption technology, optoelectronic display technology, and electronic skin. However, there are strict requirements for the properties of photochromic hydrogels in practical engineering applications, especially in some extreme application environments. The preparation of photochromic hydrogels with high transparency, high toughness, fast response, colour reversibility, excellent electrical conductivity, and anti-freezing property remains a challenge. In this study, a novel photochromic hydrogel (PAAm/SA/NaCl-Mo 7) was prepared by loading ammonium molybdate (Mo 7) and sodium chloride (NaCl) into a dual-network hydrogel of polyacrylamide (PAAm) and sodium alginate (SA) using a simple one-pot method. PAAm/SA/NaCl-Mo 7 hydrogel has excellent conductivity (175.9 S/cm), water retention capacity and anti-freezing properties, which can work normally at a low temperature of −28.4 °C. In addition, the prepared PAAm/SA/NaCl-Mo 7 hydrogel exhibits fast response (<15 s), high transparency (>70 %), good toughness (maximum elongation up to 1500 %), good cyclic compression properties at high compressive strains (60 %), good biocompatibility (78.5 %), stable reversible discolouration and excellent sensing properties, which can be used for photoelectric display, information storage and motion monitoring. This work provides a new inspiration for the development of flexible electronic skin devices. [Display omitted] [ABSTRACT FROM AUTHOR]

A Ta-modified layer was prepared on γ-TiAl by double-glow plasma surface metallurgy technique. Based on the results of high-temperature oxidation tests at 700, 800, and 900 °C, we studied the morphology, depth profile, and phase of γ-TiAl and Ta-modified layer by scanning electron microscopy, energy spectrum analysis, and X-ray diffraction analysis. Results showed that the Ta-modified layer was tightly bonded to the substrate without voids and cracks, consisting of the α-Ta outer layer and inner diffusion layer. It was found that the isothermal oxidation kinetic curves of the TiAl with the Ta-modified layer followed the parabolic rate law. Ta element promoted the diffusion of Al and formation of uniformly mixed Al2O3/Ta2O5 films, which prevented the inward diffusion of oxygen and help to the improved high-temperature oxidation resistance. [ABSTRACT FROM AUTHOR]

Coronary microembolism (CME) is commonly seen in the peri-procedural period of Percutaneous Coronary Intervention (PCI), where local platelet activation and endothelial cell inflammation crosstalk may lead to micro thrombus erosion and rupture, with serious consequences. Qihuang Zhuyu Formula (QHZYF) is a Chinese herbal compound with high efficacy against coronary artery disease, but its antiplatelet mechanism is unclear. This study aimed to elucidate the effects and mechanisms of QHZYF on sodium laurate-induced CME using network pharmacology and in vitro and in vivo experiments. We employed high-performance liquid chromatography mass spectrometry to identify the main components of QHZYF. Network pharmacology analysis, molecular docking and surface plasmon resonance (SPR) were utilized to predict the primary active components, potential therapeutic targets, and intervention pathways mediating the effects of QHZYF on platelet activation. Next, we pretreated a sodium laurate-induced minimally invasive CME rat model with QHZYF. In vivo experiments were performed to examine cardiac function in rats, to locate coronary arteries on heart sections to observe internal microthrombi, to extract rat Platelet-rich plasma (PRP) for adhesion assays and CD62p and PAC-1 (ITGB3/ITGA2B) flow assays, and to measure platelet-associated protein expression in PRP. In vitro clot retraction and Co-culture of HUVECs with PRP were performed and the gene pathway was validated through flow cytometry and immunofluorescence. Combining UPLC-Q-TOF/MS technology and database mining, 78 compounds were finally screened as the putative and representative compounds of QHZYF, with 75 crossover genes associated with CME. QHZYF prevents CME mainly by regulating key pathways of the inflammation and platelets, including Lipid and atherosclerosis, Fluid shear stress, platelet activation, and PI3K-Akt signaling pathways. Five molecules including Calyson, Oroxin A, Protosappanin A,Kaempferol and Geniposide were screened and subjected to molecular docking and SPR validation in combination with Lipinski rules (Rule of 5, Ro5). In vivo experiments showed that QHZYF not only improved myocardial injury but also inhibited formation of coronary microthrombi. QHZYF inhibited platelet activation by downregulating expression of CD62p receptor and platelet membrane protein αIIbβ3 and reduced the release of von Willebrand Factor (vWF), Ca2+ particles and inflammatory factor IL-6. Further analysis revealed that QHZYF inhibited the activation of integrin αIIbβ3, via modulating the PI3K/Akt pathways. In in vitro experiments, QHZYF independently inhibited platelet clot retraction. Upon LPS induction, the activation of platelet membrane protein ITGB3 was inhibited via the PI3K/Akt pathway, revealing an important mechanism for attenuating coronary microthrombosis. We performed mechanistic validation using PI3K inhibitor LY294002 and Akt inhibitor MK-2206 to show that QHZYF inhibited platelet membrane protein activation and inflammation to improved coronary microvessel embolism by regulating PI3K/Akt/αIIbβ3 pathways, mainly by inhibiting PI3K and Akt phosphorylation. QHZYF interferes with coronary microthrombosis through inhibition of platelet adhesion, activation and inflammatory crosstalk, thus has potential in clinical anti-platelet applications. Calyson, Oroxin A, Protosappanin A, Kaempferol and Geniposide may be the major active ingredient groups of QHZYF that alleviate coronary microthrombosis. [Display omitted] [ABSTRACT FROM AUTHOR]

We investigated the temporal evolution of light-induced scattering in [LiNbO.sub.3]:Fe,In crystals with different doping concentrations. A special behavior of the beam fanning was found when the intensity of the incident light was relatively weak. In this case the beam fanning became stronger at the beginning of the illumination and then was greatly reduced, which was observed only at strong incident light intensities. This phenomenon was analyzed on the basis of the saturation space-charge field. The intensity threshold effect and the concentration threshold effect were successfully explained. OCIS codes: 160.5320, 090.2900.