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Bridge expansion joints (BEJs) are equipped at the girder end of long-span railway bridges to ensure the reliable transition of the track. BEJs should have suitable dynamic stiffness to ensure the running safety and stability of the vehicle. To explore the influence of dynamic vertical stiffness of BEJs on the dynamic response of vehicle, track, and bridge, a three-dimensional vehicle-track-bridge coupled model is established, and the influence of sleeper spacing and vehicle speed are taken into consideration. Taking a high-speed railway line in China as a case study, the dynamic response of the whole system is calculated. The results show that (1) the dynamic response of BEJs and the vehicle is affected by the vehicle speed and sleeper spacing. With the increase of vehicle speed and sleeper spacing, the dynamic response of the system increases; (2) the vertical stiffness of BEJs will affect the dynamic response of BEJs and the interaction between the wheel and rail: the vertical dynamic displacement of movable sleeper will exceed the limit if the vertical stiffness of pressure-bearing is insufficient, and the wheel unloading rate may exceed the limit if the vertical stiffness of the cushion plate is insufficient. Based on the results, the larger vertical stiffness of the cushion plate and pressure-bearing is recommended. These results have been applied to the design of BEJs on the studied railway line, which are in good service condition at present. [ABSTRACT FROM AUTHOR]

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 hysteresis loss of Ni–5 at.%W (Ni5W) substrate contributes considerably to the alternating current (AC) loss of coated conductors (CCs) working at low transporting current or low-frequency field. In the present work, the evolution of texture and magnetic properties in Ni5W substrates is analyzed and also the relationship between magnetic properties and the extrinsic characteristics (evolved due to the processing techniques) is determined. By making the comparison, we discovered the magnetic domain structures of Ni5W substrates for the first time, achieving a strip/branched domain structures in the recrystallized substrates. The hysteresis loss has been decreased dramatically for the recrystallized substrates. Interestingly, we also observed that this loss is also related to the annealing temperature in the fully recrystallized substrates. The reduced loss can be mainly attributed toward the decrease of grain boundary, which proves the contribution of grain size toward the reduction of hysteresis loss. This result provides a new insight to tailor the hysteresis loss of Ni5W substrates used for coated conductors. [ABSTRACT FROM AUTHOR]

Highlights • The cube texture has been realized by consuming other orientation grains. • A perfect domain structure formed because of larger grain size and more SAGBs. • Higher hysteresis loss caused by complex domain structure and sharp cube texture. • There is a discrepancy between sharp cube texture and reduction of AC loss. Abstract The metallic Ni–5 at.%W (Ni5W) substrate with sharp cube texture is found as one of the promising candidates used for fabrication of coated conductors. However, the alternating current (AC) loss, partly contributed by the ferromagnetic Ni5W substrate is unavoidable. In this work, we analyzed the evolution of magnetic properties of Ni5W substrates via the cube texture development. The results revealed that the cube texture has an important impact related to size advantage during recrystallization, leading towards the consumption of the deformation and other orientational grains, and hence giving rise to form a sharp cube texture. Increasing the annealing temperature, the grain size is found to be increased. In the fully developed cube-textured substrate, the grain boundary was replaced by small angle grain boundaries (SAGBs). Also the magnetic domain structure was transformed from 180°-structure to a branched one with the increasing annealing temperature. This transformation is dependent on the increase of grain size, particularly, the SAGBs plays an important role in the formation of perfect domain structure. Increased coercivity and hysteresis loss in the fully textured substrate can be attributed towards the ideal cube texture and perfect complex domain structure. Therefore, a potential solution has been proposed to resolve this limitation of the sharp cube texture and increased hysteresis loss in Ni5W substrates. [ABSTRACT FROM AUTHOR]

This paper focused on the modification properties of the La2Zr2O7 (LZO) seed layers for the epitaxial growth of thick LZO buffer films on cube-textured Ni5%W (Ni5W) substrate by the metal organic deposition (MOD) method. The surface morphologies of the LZO seed layers with different precursor concentrations were described by SEM. The grain orientation and the crystallographic growth model of the LZO seed layer were characterized by the electron backscatter diffraction (EBSD). The XRD analyses reveal that the LZO buffer layers on the Ni5W substrates with and without seed layers were grown epitaxially. However, the uniformly distributed islanded LZO seed layers with highly (001)[110] rotated cube texture not only can improve the crystallinity of the subsequent LZO buffer films, but also can optimize the in-plan and out-plan orientations of the thick LZO buffer layers. [ABSTRACT FROM AUTHOR]

Abstract: Thin, biaxially textured Ni5W/Ni12W/Ni5W composite substrates for coated conductor applications have been fabricated. The particularity of this three-layer composite configuration resides in the elemental diffusion between the outer layer and the core layer. Due to the migration of elemental W, the diffusion layer in the as-annealed substrate becomes broader than that of the as-rolled substrate. The obtained tape has a sharp cubic texture on the Ni5W outer layers, and the volume fraction of cubic grains exceeds 98.8% (<10°) at the outer surfaces. In situ electron backscatter diffraction strain–stress analysis shows that the high-quality cubic texture was stable until elongations as high as 2%. The yield strength of the composite substrate approaches 240MPa and its saturation magnetization at 77K has been strongly reduced with respect to pure Ni and Ni5W substrates. The present results demonstrate that this advanced three-layer substrate is suitable for the epitaxial growth of the LZO buffer layers. [Copyright &y& Elsevier]

A sharp cube textured alloy substrates with high strength and low magnetism are required in coated conductors' applications. In this work, the cube textured Ni-7at.%W substrates, starting from advanced powder metallurgy ingots followed by Rolling Assisted Biaxially Textured Substrate (RABiTS) method, have been prepared. The fabrication processes of Ni-7at.%W tapes with sharp cube texture by spark plasma sintering(SPS) routes were described. By Electron Back Scattering Diffraction (EBSD) analysis, the percentage of the cube texture component in Ni-7at. %W tape surface is found to reach 99.4% within a misorientation angle smaller than 10°. Moreover, the formation mechanism of the cube texture in the Ni-7at. %W tape was also investigated by EBSD. Particular attention was focused on the difference of the texture components along the thickness of the partially recrystallized samples. [ABSTRACT FROM AUTHOR]

CeO2 caped La2Zr2O7(LZO) buffer layers on cube-textured Ni5W substrates were fabricated by the method of chemical solution deposition(CSD). The orientation of both LZO film and CeO2 /LZO buffer layer was investigated using conventional XRD and X-ray four circle diffractometers, respectively. The results reveal that both the LZO film on Ni5W substrates and CeO2 film on LZO buffer layer are grown epitaxially. The value of Full Width at Half Maximum (FWHM) of (111) Phi scan of CeO2/LZO buffer layer is around 8°, and the FWHM of (200) w-scan of CeO2/La2Zr2O7 buffer layer is 6.5°, indicating a good in-plan orientation of the as obtained buffer layers. It was observed by the high resolution SEM that the surface of LZO buffer layer is crack-free and very dense. The surface result observed by AFM indicates a very smooth CeO2 surface with 5.9 nm of the root mean square roughness measured in an areas of 30 x 30 μm2. AES depth profile results of CeO2/LZO buffer layers shows that the deposited LZO film could effectively prevent the diffusion of Ni into the buffer layer. [ABSTRACT FROM AUTHOR]

In this work, the capacitive deionization (CDI) performance of a single-walled carbon nanotube (CNT) electrode has been studied from the point view of charge efficiency theory. It is revealed here that the charge efficiency of a CNT electrode is strongly dependent upon the cell voltage and solution concentration. Either the high cell voltage or the low ionic strength results in a high charge efficiency, implying that CDI is expected to be a promising technique for an aqueous solution with low ionic strength. Additionally, it is found that the high decay constant and high electrical double-layer capacity are beneficial to enhance electrosorption performance.