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The inferior energy density limits the practical application and sustainable development of supercapacitors. Excellent electrode materials can effectively improve the specific capacitance and operating potential window. Thus, we deposit brush-like nickel ferrite (NiFe 2 O 4) nanosheets and CuCo 2 O 4 /CuO nanowire arrays to construct a binder-free electrode with tree-like CuCo 2 O 4 /CuO/NiFe 2 O 4 arrays. The resulting CuCo 2 O 4 /CuO/NiFe 2 O 4 electrode shows an outstanding specific capacitance (2067 F/g) and wide potential window (−0.1-0.6 V). The contribution rate of surface faradaic redox reaction is calculated to be 71% at 1 mV/s and assembled CuCo 2 O 4 /CuO/NiFe 2 O 4 //AC device realizes a remarkable energy density (77.1 Wh/kg at power density of 851.4 W/kg) and cyclic performance (92.9% of initial specific capacitance retained after 10,000 cycles). Apparently, the CuCo 2 O 4 /CuO/NiFe 2 O 4 electrode as a novel binder-free electrode has great application potential and our work offers a novel idea to construct the arrays of multicomponent composite materials. [ABSTRACT FROM AUTHOR]

Abstract Pulse-like ground motions usually have higher spectral displacements and spectral accelerations than other motions in long periods and can cause severe damage on structures. However, there is still no a generally accepted method to incorporate the features of this type motion in the code-based design spectrum. The pulse period is one of the key parameters to characterize the features of pulse-like ground motions. The relations between the pulse period and the earthquake magnitude have been well studied, and many prediction equations have been proposed. However, these results cannot be considered in the process of deriving the design spectrum of pulse-like ground motions. This paper proposes a new method to derive the acceleration and displacement design spectra of pulse-like ground motions based on the wavelet multi-resolution analysis. To consider the influence of the frequency content of ground motions, the frequency band of ground motions is divided into several continuous sub-bands. One or more ground motion components obtained by the wavelet multi-resolution analysis are used to represent the frequency content in each sub-band. Differing from previous methods, the design spectral shape of the proposed method can be changed according to the frequency content of ground motions, and the prediction equations between the pulse period and the earthquake magnitude can be used to improve the current code-based design spectrum. Highlights • A new method of deriving the design spectra of pulse-like ground motions is proposed. • Design spectral shape can be changed according to pulse feature. • The predicted pulse period can be used to improve the code-based design spectra. • Both acceleration and displacement design spectra are considered. [ABSTRACT FROM AUTHOR]

Selecting spectrum-matched ground motions is one of the critical problems in the seismic analysis and design of structures. The sum of the square errors (SSE) has been commonly used to quantitatively measure the similarity between the response spectrum of a ground motion and a target spectrum. However, it cannot represent the two-dimensional plane feature of the response spectrum because the response spectrum is treated as a one-dimensional vector in the SSE -based approaches. Considering the high-performance feature extraction of images and small-sample learning for the Siamese Convolutional Neural Networks (SCNNs), a new spectrum-matched ground motion selection method is proposed based on the SCNNs. The types of ground A, B, C, and D acceleration design spectra for the Eurocode 8 are selected as the target spectra without loss of generality. The procedures for the sample image generation, network training, testing, and spectrum-matched ground motion selection are elaborated. Analysis results indicate that using 40 samples for each class can achieve satisfactory training results. The mean response spectrum of the ground motions selected by the proposed method is matched with the target spectrum in all periods. Compared to the SSE -based approaches, the results obtained by the proposed method have a minor standard deviation. The proposed method could be used as an alternative in the ground motion selection for the dynamic analysis of structures. • Spectrum-matched ground motion selection based on the SCNNs. • The inputs are the response spectral images. • Sample generation, network training, and testing are studied. • The mean spectrum is matched with the target spectrum in all periods. • Compared to SSE -based approaches, the results have a minor standard deviation. [ABSTRACT FROM AUTHOR]

• Uncertainties in the earthquake intensity, seismic load, and calculation methods are considered. • Three demands moment, thrust, and diametric distortion are considered. • Analytical method is used as an integral part of the seismic demand models. • Bayesian approach is used to estimate the unknown model parameters. • The probability distributions of the seismic demands can be obtained. This paper proposes convenient probabilistic models to estimate the seismic demands of circular tunnels to transversal seismic load. The uncertainties in the earthquake intensity, seismic load, and calculation methods are fully considered. Peak ground velocity PGV is selected as an essential earthquake intensity parameter because it is more correlated with the earthquake damage of underground structures, and a probabilistic model of PGV is proposed. Because the seismic response of tunnel linings is highly correlated with the free-field ground deformation, the maximum free field shear strain g max is selected as the seismic load parameter. A probabilistic model of g max is developed based on a series of seismic site response analyses. PGV plays a key role in the estimation of g max. The analytical methods have been proposed to estimate the seismic response of tunnels. However, the results are usually biased, and the underlying uncertainties have not been well studied. To obtained unbiased seismic response estimates and capture the uncertainties in the calculation methods, the probabilistic seismic demand models are constructed by developing correction terms to the analytical method. The maximum moment M max , thrust T max , and diametric distortion Δ d / d max of the tunnel lining are considered. A pseudo-static analysis approach is used to simulate the seismic response of tunnels, and Bayesian updating is used for the model optimization and parameter estimation. The results of this paper can be used in the seismic design and reliability analysis of circular tunnels. [ABSTRACT FROM AUTHOR]

This paper presents a systematic study to develop the probabilistic seismic capacity models for circular tunnel linings. The uncertainties of lining parameters, soil properties, and ground motions are all considered. The Bayesian approach is used to estimate the model parameters based on the capacity samples simulated by a large number of refined dynamical numerical analyses. Finally, probabilistic capacity models are separately constructed for circular tunnels at three performance levels. To demonstrate the properties of the proposed method, the capacity models are used to estimate the capacities and the fragility curves of a typical tunnel. It is concluded that (1) the probabilistic model can quickly estimate the probability distribution of capacity based on existing parameters, with the estimated median value closely approximating the numerical result; (2) the proposed probabilistic capacity models can be used to quickly derive fragility curves for specific tunnels, which facilitates safety evaluation and performance-based seismic design of tunnels. [ABSTRACT FROM AUTHOR]

Abstract By electrochemical deposition, the bimetallic Ni Co coating with novel hierarchical micro-spherical structures was prepared on carbon steel substrate. The properties including surface morphologies, structures, chemical compositions, wetting properties, as well as the growth mechanism of the electrodeposited hierarchical structure were observed by SEM, XRD, XPS and contact angle measurements. After modification with low surface energy materials, the Ni Co coating with the hierarchical micro-spherical structures deposited at −1.8 V displayed high super-hydrophobic properties with a water contact angle of around 165°. By electrochemical measurements, the anti-corrosion performances between planar and super-hydrophobic Ni Co coating were compared. And the latter exhibited excellent corrosion protection for bare carbon steel by limiting the contact area to reduce its interaction with corrosive medium. Graphical abstract Unlabelled Image Highlights • The Ni Co coating with novel hierarchical micro-spherical structure was prepared. • The coating displayed super-hydrophobic properties with a contact angle of 165°. • The super-hydrophobic coating exhibited excellent corrosion protection. [ABSTRACT FROM AUTHOR]

A new hybrid genetic-simulated-annealing (GSA) optimization algorithm is introduced to solve the multivariable minimization problem for surface wave inversion. The algorithm is effective for both global and local searches due to its combination of the reproduction and selective generation schemes from genetic algorithms (GA) with the nonlinear scaling fitness function and perturbation scheme from simulated annealing (SA). The hybrid GSA algorithm can reduce the risk of a solution becoming trapped in a local minimum and improve global searching efficiency. A mathematical test function as well as surface wave examples are used to examine the advantages and performance of the GSA algorithm. Comparisons of GA, SA, and GSA inversion results demonstrates that GSA can yield the smallest uncertainty and greatest efficiency, and improve the statistical confidence of using surface wave testing for shear-wave velocity profiling. [ABSTRACT FROM AUTHOR]

Passive film is a natural barrier against corrosion, which forms spontaneously in alkaline solution. But as a key problem for corrosion resistance, the growth and failure process of passive film has not been clearly confirmed. In this paper, the fine structure of passive film is explored on the atomic scale, and the growth mode of crystals is demonstrated; ion channels are found in inner passive film, which explains the appearance of defect zones and concentrated attack of chloride ions in corrosion. This study will help to judge the corrosion initiation from the perspective of micro damage of passive film. • A fine 5-layer structure of passive film in the growth process was found. • Crystal growth and amorphous aggregation is promoted by chloride ions in short term. • Putting forward special ion channel is the way that chloride invade the passive film. [ABSTRACT FROM AUTHOR]

• The effect of additional element dissolving on the solid solubility of Zn in Mg alloy is predicted. • Ca is predicted as the element enhancing the solid solubility of Zn. • The properties of the element enhancing the solid solubility of Zn in Mg alloy are given. The solid solubility of Zn is an important factor for designing the Mg-Zn based alloy. This work aims at developing a strategy to predict the effect of additional element dissolving on the solid solubility of Zn in Mg alloy based on the first-principles calculation. The strategy is composed of two criteria. The behaviors of X in controlling the lattice distortion and energy fluctuation caused by Zn-Mg interaction are investigated as the main criterion, and the precipitation of Zn accelerated by Zn-X interaction is further examined as the supplementary criterion. After considering the metallic elements across the periodic table (period II to VI), Ca is recommended as the element enhancing the solid solubility of Zn and the others are recommended as the elements reducing the solid solubility, which has a considerable agreement with the available thermodynamic assessments. The first-principles strategy suggests that an element X enhancing the solid solubility of Zn in Mg alloy should satisfy two conditions. Firstly, X can provide the opposite geometric and energetic effect of single Zn on Mg host, and secondly, there is no attractive interaction between Zn and X. This work explores a pathway for extending Hume-Rothery rules from the binary alloy system to the ternary, which serves the development of alloy design theory. [ABSTRACT FROM AUTHOR]