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•Layered porous ternary ZnS/ZnO-In2O3 with dual defects are obtained successfully.•The dual defects work in tandem to realize the charges directed flow.•The transfer mode of ternary ...photocatalyst is followed by Z-scheme.•Extensively heterojunctions facilitate the separation and migration of charges.
The construction of heterojunction is an effective strategy to manipulate the dynamic behaviors of photo-induced charges. It is essential for wide band gap semiconductor to introduce defects reasonably to mediate electronic properties and charge behaviors. Herein, through an in situ etching growing method and thermal treatment, dual defective ternary photocatalyst ZnS/ZnO-In2O3 with porous layered structure and extensive heterojunction interfaces has been prepared for visible light photocatalysis of water splitting. The suitable position of intermediate energy level endows the ternary photocatalyst with the ability of electrons directed flow between the different components, and the transfer mode follows Z-scheme. The cascaded dual defects on ZnO and ZnS synergistically facilitate the efficient separation of photo-generated charges through the intimate interface, and further enhance visible light photocatalysis performance. This work is expected to enlighten the rational design of dual defects for wide bandgap semiconductor.
For a wide-flanged composite box girder bridge, the risk of fatigue cracking in the external inclined strut welded joint under the fatigue vehicle load is a problem. The main purposes of this ...research are to verify the safety of the main bridge of the Linyi Yellow River Bridge, a continuous composite box girder bridge, and to propose suggestions for optimization. In this research, a finite element model of one segment of the bridge was established to investigate the influence surface of the external inclined strut, and, using the nominal stress method, it was confirmed that the fatigue cracking of the welded details of the external inclined strut was risky. Subsequently, a full-scale fatigue test of the external inclined strut welded joint was carried out, and the crack propagation law and S-N curve of the welded details were obtained. Finally, a parametric analysis was conducted with the three-dimensional refined finite element models. The results showed that the welded joint in the real bridge has a fatigue life larger than that of the design life, and methods such as increasing the flange thickness of the external inclined strut and the diameter of the welding hole are beneficial to improve its fatigue performance.
Controlling the impact behavior of a droplet on a superhydrophobic surface is a significant challenge for many applications. Instead of texturing the surface, this study investigated the effect of ...adding surfactants on the morphology of the droplet after it impacts superhydrophobic surfaces. The results showed that adding low concentrations of sodium dodecyl sulfate (SDS) surfactant prevents fragmentation and splashing. High concentrations of SDS can inhibit rebound and allow droplets to be easily deposited on surfaces after impact. When the droplet size was 3.51 mm and the SDS concentration was above the critical micelle concentration, the contact time of the solution increased by a maximum of 1.30 times compared to that of pure water. In a high-concentration SDS solution, the surfactant molecules can quickly migrate to the newly generated interface during the spreading stage, reducing the interfacial tension and causing wetting changes. The results of this study are expected to contribute toward establishing a simple method to inhibit splashing and increasing contact time on superhydrophobic surfaces.
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The dominant source of thromboembolism in heart comes from the left atrial appendage (LAA). An occluder can close LAA and significantly reduce the risk of strokes, particularly for those patients ...with atrial fibrillation. However, it is technically challenging to fabricate an LAA occluder that is appropriate for percutaneous implantation and can be rapidly endothelialized to accomplish complete closure and avoid severe complication. Hypothesizing that a fast migration rate of endothelial cells on the implant surface would lead to rapid endothelialization, we fabricated an LAA occlusion device for interventional treatment with a well-designed 3D architecture and a nanoscale 2D coating. Through screening of biomaterials surfaces with cellular studies in vitro including cell observations, qPCR, RNA sequencing, and implantation studies in vivo, we revealed that a titanium–nitrogen nanocoating on a NiTi alloy promoted high migration rate of endothelial cells on the surface. The effectiveness of this first nanocoating LAA occluder was validated in animal experiments and a patient case, both of which exhibited successful implantation, fast sealing and long-term safety of the device. The mechanistic insights gained in this study will be useful for the design of medical devices with appropriate surface modification, not necessarily for improved cell adhesion but sometimes for enhanced cell migration.
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Repeatable printing of invisible multicolor luminescence patterns with long retention times on transparent substrates is of significant importance, but it remains a formidable challenge. Here, two ...novel hydrazone‐based on/off fluorescent photoswitches with decent emission quantum efficiencies, good reversible photoisomerization properties, and extremely long thermal half‐lives, were designed and synthesized. Excitingly, X‐ray crystallography data of both Z and E isomers of one hydrazone‐based photoswitch were obtained. Multiple emission colors of blue, cyan, green, yellow, and orange can be obtained readily for these two photoswitches upon coordination with various zinc salts. Moreover, the photo‐controlled rewritable printing of invisible multicolor images with high resolution was achieved by using these photoswitches. Importantly, the legibility of the printed patterns can last at least over 3 months without detectable emission intensity loss under ambient conditions.
Two hydrazone‐based photoswitches with high emission quantum yields, excellent reversible photoisomerization properties, and long thermal stability are reported. Impressively, multiple emission colors can be obtained readily for these two photoswitches upon coordination with various zinc salts. Furthermore, the photo‐controlled rewritable printing of invisible multicolor images with extremely high resolution and stability is achieved.
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•A fluorine-free waterborne NP-GLIDE coating was developed with comparable properties to it’s solvent based counterpart.•The environmentally friendly fabrication process will ...accelerate industrialization.•The coating has excellent optical clarity, durability and self-cleaning properties.
An environmentally friendly water-based NP-GLIDE polyurethane (PU) coating has been developed. The term NP-GLIDE as described herein suggests that water, organic solvents, or contaminants in these liquids have no problem to glide down the coating or that the coating bears nano-pools of a grafted lubricating ingredient for dewetting enablement. To prepare a coating, a blocked polyisocyanate and a graft copolymer polyol-g-PDMS consisting of a water-dispersible polyol backbone and poly(dimethyl siloxane) (PDMS) side-chains were co-dispersed in water containing 5.0 vol.% of dipropylene glycol monomethyl ether, cast onto a substrate to evaporate the solvent, and then thermally cured. As the liquid-like PDMS is covalently bound to the polyol backbone, it could not undergo macrophase separation and instead formed nano-pools with diameters of less than 30 nm throughout the polyurethane matrix. Meanwhile, the surface of the coating changed from solid-like to liquid-like due to the surface enrichment by PDMS. Of the three families of polyol-g-PDMS samples that were synthesized and evaluated, only one of these polyol-g-PDMS families yielded NP-GLIDE coatings with superior properties. All of the test liquids with surface tensions above 23 mN/m readily and cleanly slid down the optimized coatings that had a hardness of 3H. Moreover, both marker ink and a commercial paint contracted on these coatings and the contracted ink could be readily and cleanly removed with tissue paper without leaving any traces behind. Moreover, the ink contraction capability was maintained after the writing and erasing test had been performed for more than 30 cycles. The environmental friendliness of the coating formation process and the superior anti-smudge performance of the resultant coatings suggested that they have excellent potential for practical applications.
•China’s energy productivity (EP) change determinants were identified at city level.•Spatial character and distributional evolution of China’s EP were analyzed.•China’s overall EP exhibited a ...downward trend during the study period.•Technological and technical efficiency changes were key factors in EP decrease.
Energy productivity is a key indicator to evaluate energy efficiency. However, few researchers focus on China’s energy productivity at the city level or its spatial patterns. The aim of this paper is to investigate the determinants and spatial character of changes to China’s energy productivity at the city level. The change in energy productivity is decomposed using a distance function approach, and its spatial character is identified through exploratory spatial data analysis, based on data from 248 cities between 2010 and 2014. The study revealed that China’s overall energy productivity exhibited a downward trend caused primarily by the effects of technological and technical efficiency changes at the city level. Additionally, significant spatial autocorrelation existed in energy productivity, although most cities did not show significant spatial clustering. Based on the above results, we provide relevant suggestions for policymakers.
Digitalization and intellectualization of energy system require the fault information of energy conversion devices to be captured as accurately as possible from the massive data, so as to realize ...early fault alert. However, the comprehensiveness of feature extraction, the setting difficulty of model parameters and applicability of various scenarios have shortcomings by conventional methods, leading to their limitations in measured signals with multi-source and multi-feature information. Therefore, this paper exploits a quantitative diagnostic method named refined composite hierarchical multiscale Lempel-Ziv complexity (RCHMLZC). Firstly, the enhanced hierarchical decomposition and multiscale Lempel-Ziv complexity (MLZC) are coupled to develop hierarchical multiscale Lempel-Ziv complexity (HMLZC), which overcomes the drawback of MLZC that cannot quantify the complexity of signals at different frequencies. Secondly, RCHMLZC is proposed to solve the problem that LZC value of HMLZC fluctuates greatly under high scale factors, and then is used to extract the features of vibration signals. Finally, the extracted features are input into the random forests model to realize the efficient recognition of different status signals of rotating energy devices. A total of 14 types of multi-feature fault signals from bearings, shafting and runner are used to verify the reliability and superiority of the proposed method. Compared to the five conventional models, the comprehensive indicators of the proposed method for bearing fault experiments are improved by 1.549%, 4.637%, 14.153%, 20.242% and 22.112%, while the values for the shafting fault experiments are improved by 0.404%, 0.427%, 2.778%, 2.722% and 5.895%. In addition, the proposed method is applied to the analysis of the fault cases of hydraulic turbine, demonstrated the ability to zero miscalculation. It would be a helpful tool to improve energy conversion efficiency and reduce maintenance cost.
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In this paper, we investigate the maximum flow routing strategy with the service function chain (SFC) constraints in the space information networks (SINs), where a SFC consists of a specific ordered ...sequence of service functions, and the mission flow must go through these functions in a predefined order. The time-varying SIN is modeled by the time-expanded graph (TEG). We formulate the maximum flow routing strategy problem with the SFC constraints as a linear programming (LP) problem. Furthermore, for a large-scale SIN, as the complexity of solving the LP problem is still very high, we propose a novel low-complexity SFC-constrained graph theory based (SFC-GT) algorithm. Specifically, we formulate this problem as one special single commodity maximum flow problem, where this flow must satisfy the SFC constraints. We first define the SFC-constrained residual network and the SFC-constrained augmenting path. Afterwards, we iteratively search the SFC-constrained augmenting path and update the SFC-constrained residual network. Simulation results demonstrate our proposed SFC-GT algorithm can achieve near-optimal performance with much less complexity.
