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The second-generation high-temperature superconducting (2 G-HTS) tapes are subjected to complex stress/strain in practical applications. For the complex operation conditions, lamination techniques are widely used to improve the robustness of 2 G-HTS tapes. However, lamination makes the 2 G-HTS tape structure more complicated, which can significantly affect their electro-mechanical behaviors. In this work, uniaxial monotonic tensile tests were performed to obtain the stress-strain relationship and the strain dependence of critical current (I c (ε)) in liquid nitrogen conditions. Two types of laminated 2 G-HTS tapes (copper-laminated and stainless steel-laminated) were compared with copper-plated 2 G-HTS tapes. The results showed that the irreversible tensile strains of Cu-laminated and SS-laminated tapes were much higher than that of Cu-plated tapes, which increased by ∼35 % and ∼60 %, respectively. High consistency between the experimental and theoretical I c values in 2 G-HTS tapes under tensile strain was verified by the I c (ε) model. Based on the residual strain (ε res) calculation of composite multilayer structures, we confirmed that it was mainly due to the increase of the compressive residual strain of superconducting layers. Further, tensile fatigue tests also confirmed the significant improvement of the tensile fatigue electro-mechanical behaviors in the laminated 2 G-HTS tapes. Finally, 2D X-ray and SEM cooperative analysis were used to characterize the tape microstructure before and after fatigue, and the correlation between micro-defects and non-destructive imaging features was established. It was found that the internal solder layer and its interface were seriously damaged to release the stress. This work provides a strategy to improve the electro-mechanical behaviors of 2 G-HTS tapes by adjusting the composite structure to change residual strain. • Laminated 2 G-HTS tapes exhibited superior tensile electromechanical behaviors compared with the Cu-plated tapes. • High consistency between the experimental and theoretical I c values in 2 G-HTS tapes under tensile strain was verified. • Higher ε irr in laminated 2 G-HTS tapes was mainly due to the increase of residual strain in superconducting layers. • It provides a strategy to improve the electro-mechanical behaviors of 2 G-HTS tapes by adjusting the composite structure. [ABSTRACT FROM AUTHOR]

Copper stabilizers play an essential role in second-generation high-temperature superconducting (2G-HTS) tapes. Corrosion or aging of the copper stabilizer is unavoidable and affects the tape performance. In this study, aging tests were performed on fresh copper-plated 2G-HTS tapes under steady-state damp heat conditions, in accordance with the IEC 60068–2-78:2012 regulations. To accelerate the aging, the conditions were set as 40 °C, a relative humidity of 93%, and test durations of up to 48 h. The surface contact resistivity (ρ c) in liquid nitrogen was measured for fresh and aged specimens under normal pressure of up to 160 MPa. The results indicated that ρ c increased with the test duration and tended to become saturated. After 48 h aging tests, the ρ c of the specimens was three times higher that of the fresh 2G-HTS tapes. Moreover, the microstructure of the copper stabilizer was characterized. Height fluctuations were observed on all the specimen surfaces, which might be the reason for the ρ c scattering. X-ray photoelectron spectroscopy elemental analysis revealed higher amounts of carbon and oxygen on the surfaces of the specimens after aging, which significantly reduced the purity of the copper stabilizer. It was also found that Cu 2 O was the main product on the tape surface during the reaction with oxygen and, water vapor and so on. This study provides a reference for the design of non-insulated coils and the preservation of 2G-HTS tapes. • The surface contact resistivity of specimens increased with the accelerated aging duration and tended to become saturated. • Height fluctuations were observed on specimen surfaces via EBSD, which may have been the reason for resistivity scattering. • XPS elemental analysis revealed higher amounts of carbon and oxygen in aged specimens. Cu 2 O was the main aging product. [ABSTRACT FROM AUTHOR]

Creep damage of Sn–Ag–Cu micro-joints is inevitable in service, even at room temperature. In this study, Ni-decorated reduced graphene oxide (Ni-RGO) nanosheets were rationally selected as a promising reinforcement in Sn-3.0Ag-0.5Cu (SAC305) solder to improve creep resistance. Tensile creep tests were conducted on the Ni-RGO reinforced SAC305 micro-joints under 8–14 MPa stress at 100–150 °C by dynamic mechanical analysis (DMA) equipment. Micrography and fractography were observed using FESEM. The stress exponent (n) increased from 5.83 to 6.37, and the activation energy (Q) rose from 68.80 to 75.41 kJ/mol as 0.10 wt% Ni-RGO nanosheets were added into the SAC305 solder, indicating the occurrence of diffusion mechanism. By adding a trace amount of Ni-RGO nanosheets (no more than 0.10 wt%), the crack initiation was prone to occur at the wave-valley of the continuous scallop shaped interface, where the diffusion of vacancies occurred, resulting in hybrid-fracture features of quasi-cleavage and dimples. It can be concluded that the inclusion of trace amounts of Ni-RGO nanosheets can enhance the creep resistance of SAC305 micro-joints during service. [Display omitted] • The creep deformation process was controlled by the diffusion mechanism. • The hybrid-fracture characteristics of quasi-cleavage and dimples occurred. • The addition of Ni-RGO nanosheets improved the creep resistance of the micro-joints. [ABSTRACT FROM AUTHOR]

• A modified transverse tensile testing method by using epoxy adhesive was developed. • Decreasing operation temperature can improve the delamination strength of CCs. • At 77 K, the critical stress is almost double compared to the result at RT. A setup of transverse tension measurements of high temperature superconductor (HTS) RE-Ba-Cu-O coated conductors are modified for simplicity. Modification includes using high strength epoxy films instead of solder as adhesive agents and changing the shape of contact surface between test samples and anvils. This method was designed to measure delamination strength of stabilizer free REBCO coated conductors with a width more than 10 mm. It is also applicable to REBCO coated conductors with copper or stainless-steel stabilizers. Samples made by the IBAD/PLD process were tested by this test. Effect of operation temperature on the delamination strength of coated conductors was investigated. In addition, fracture surfaces of delaminated samples were studied. [ABSTRACT FROM AUTHOR]

Pulsed lasers were used to drill small holes distributed homogeneously on buffer layers of coated conductors, aiming at improving their mechanical properties. Each hole should be engraved by only one pulse of laser for practicality. The effect of pulsed laser engraving on buffer layers, CeO2 in this study, were investigated. The size and depth of the hole can be controlled by adjusting laser parameters. REBa2Cu3Oy (REBCO) layers were then grown on the laser patterned buffer. The growth mechanism of REBCO above the drilled holes was studied. In addition, influence of drilled holes on the critical currents of coated conductors were studied. Finally, the effect on mechanical strength of as grown samples were studied by measuring their delamination strength under transverse tension. [ABSTRACT FROM AUTHOR]

[Display omitted] • BaHfO 3 doped Eu 1 Ba 2 Cu 3 O 7-δ films was fabricated by an ultra-fast pulsed laser deposition. • The periodic change of growth conditions during the multi-turn dynamic deposition results a distinct lamellar structure in doped film. • A strong correlation between dopant content and BaHfO 3 self-assembly mechanism was established. • The predominant pinning mechanism transforms form random pinning to correlated pinning with the increase of dopant content. Structure modulation of rare-earth barium cuperates (REBCO) superconducting films plays an essential role in the flux pinning behaviors. In this paper, nano-composite EuBa 2 Cu 3 O 7−δ -BaHfO 3 (EuBCO/BHO) films were deposited by the ultra-fast pulsed laser deposition technique. All nano-composite films exhibited high-quality orientation under the growth rates up to 100 nm/s. TEM cross-sectional analysis reveals that the EuBCO/BHO films have a distinct lamellar structure, which is related to the periodic change of growth conditions during the multi-turn dynamic deposition. In addition, the morphology of BHO varies with dopant content, which suggests a strong correlation between dopant content and the BHO self-assembly mechanism. Consequently, the vortex behavior shifts from giant-flux creep to vortex-glass formation at the thermally activated flux flow region as the dopant content increases. The primary flux pinning behaviors change from random to correlated pinning with the increase of dopant content at 4.2 K. Due to the larger contribution of the correlated pinning machinimas, the 8% BHO-doped EuBCO film exhibits the highest J c value at 4.2 K, with moderate fields (below 8 T) among all the three films. At 4.2 K and 14 T, the 6% BHO doped EuBCO film has the highest F p value attributing to the predominate random pinning mechanism. [ABSTRACT FROM AUTHOR]

Background: Recent studies have reported conflicting associations between egg consumption and the risk of all-cause or cardiovascular disease (CVD) mortality, including ischemic heart disease (IHD) mortality and stroke mortality. With accumulating evidence, up-to-date evidence about the association should be synthesized.Objectives: We aimed to assess the association of the risk of all-cause and CVD mortality with egg consumption.Methods: We searched the PubMed, Embase, and Web of Science databases through 3 November, 2021 for observational studies conducted in participants ≥18 y of age and which provided ORs, RRs, or HRs and 95% CIs for ≥3 egg consumption categories or for increased intake of egg addressing the associations of interest. A random-effects model was used to pool the reported risk estimates. Restricted cubic splines were used to examine the dose-response association.Results: Twenty-four articles with 48 reports (25 for all-cause mortality, 11 for CVD mortality, 6 for IHD mortality, and 6 for stroke mortality) involving 11,890,695 participants were included. Intake of each 1-egg/d increment was associated with increased risk of all-cause mortality (RR: 1.06; 95% CI: 1.02, 1.10; P = 0.008), but the association was restricted to women, Americans, and studies with adjustments for hyperlipidemia. Egg consumption was linearly associated with CVD mortality only in participants >60 y of age, Americans, studies with follow-up duration ≥15 y, and studies with adjustments for hyperlipidemia (P ≤ 0.018). No significant association was found between egg consumption and IHD or stroke mortality (P ≥ 0.080).Conclusions: Egg consumption was linearly associated with a modestly increased risk of all-cause mortality and, in older participants, Americans, and studies with longer follow-up or adjustments for hyperlipidemia, CVD mortality. These findings suggest that it may be prudent to avoid high egg consumption. [ABSTRACT FROM AUTHOR]

Conductor on round core (CORC) cables with the features of flexibility and a high engineering current density have been a potential candidate for high magnetic field magnets and accelerator magnets. In these applications, reducing the magnetization loss generated in superconductors is essential in the process of design. CORC cables fabricated by multifilament-coated conductor (CC) tapes have been proved to have a low magnetization loss. However, the degradation of the critical current (Ic) and additional coupling losses significantly affects the performance of CORC cables. In this article, ultraviolet laser cutting technology is used to scribe both the superconducting layer and copper stabilization layers into narrow filaments. First, the magnetization loss of a single tape with different numbers of filaments was measured by a calibration-free method. Then, based on the testing results of a single tape, two typical CORC cables are wound by 10-mm-wide and 4-mm-wide CC tapes. The magnetization loss of cables made of striated tapes was discussed by both experimental and numerical methods. It is found that the magnetization loss significantly decreases with an increasing number of filaments under a high background magnetic field. The magnetization losses decrease in CORC cables made of striated CC tape. Due to the reduced coupling loss and attenuated shielding effect, there is not much difference between the two values of the magnetization loss reduction rates in CORC cables and single tapes. The conclusions obtained in this article will be instructive for the future design of CORC cables. [ABSTRACT FROM AUTHOR]

The formation of interfacial intermetallic compounds (IMCs) such as Cu 6 Sn 5 , Cu 3 Sn or platelet-shaped Ag 3 Sn which are formed in reflow soldering process will directly destroy the soldering reliability. Magnetic pulse welding (MPW), as a solid state welding technique can effectively restrain or even impede the formation of interfacial IMCs. In this paper, Cu and Sn dissimilar metals were welded by MPW under the discharge energy from 17 to 31 kJ. The typical wavy interface and metal jet flow were found in all samples. When the discharge energy reached 31 kJ, a typical gradient nanograined (GNG) interface has been observed to undergo an evolution from a sub-micron secondary solid solution of Cu 6.26 Sn 5 IMCs to a nanoscale secondary solid solution of Cu 81 Sn 22 IMCs, followed by the formation of nanoscale equiaxed α-Cu grains, and ultimately leading to the deformed elongated nanoscale α-Cu grains. This discontinuous distribution of the aforementioned phases occurs specifically at the interface of the 23 kJ_1.5 mm sample. In contrast, when subjected to a discharge energy of 17 kJ, there were no indications of a secondary solid solution of Cu 6.26 Sn 5 IMCs or elongated nanoscale α-Cu grains. However, a discontinuous secondary solid solution of Cu 81 Sn 22 IMCs was observed to form at the Cu/Sn interface under these conditions. Based on these findings, the utilization of microprojection welding (MPW) techniques involving Cu and Sn-based solder in the microscale is anticipated to serve as a highly efficient and automated technology within the field of electronic micropackaging. [Display omitted] • The wavy interface and metal jet were formed at the Cu/Sn interface. • The gradient nanograined interface has been observed. [ABSTRACT FROM AUTHOR]

[Display omitted] • The stoichiometry and the sintering temperature affect the supersaturation of YBCO films. • The diffusion distance to the reaction site affects the supersaturation of YBCO films at the reaction site. • Low supersaturation favors the growth of c -axis orientation and suppresses the growth of random orientation in YBCO films. • A novel architecture consisting of a multi-layer stack significantly improves the strong texture of YBCO films. Chemical solution deposition is widely used in the preparation of rare-earth-based cuprate superconducting thin films, namely RE x Ba 2 Cu 3 O 7- y (RE = rare earth element). The crystallographic orientation of the films is strongly dependent on the degree of supersaturation during crystallization. In this paper, we systematically studied the crucial factors affecting supersaturation, such as the type and stoichiometry of the rare earth element and the sintering temperature. Furthermore, the relationship between c -axis orientation and supersaturation was established. The results demonstrate that a small RE ionic radius (e.g., RE = Yb) and reduced rE -stoichiometry, studied on the example of yttrium, are beneficial for the growth of c -axis-oriented films at lower temperatures. In addition, a Y-O/Ba-Cu-O stacked-layer structure was proposed to regulate the diffusion distance to the reaction site. Compared with a Y-Ba-Cu-O single-layer, a c -axis orientation percentage of more than 40 % is achieved in the Y-O/Ba-Cu-O stacked-layer at even lower sintering temperatures. The results suggest that a low supersaturation is favorable to promote the growth of c -axis-oriented nuclei and therefore suppresses the growth of random orientations. This paper provides a new strategy to realize orientation modulation of rare-earth-based cuprate superconducting thin films by controlled chemical solution method. [ABSTRACT FROM AUTHOR]

• It is an efficient, accurate and real-time detection algorithm. • High precision detection technology is not disturbed by field noise. • It provides technical support for research related to variable fertilization. Efficient and accurate detection of fertilizer discharge volume is a prerequisite for high-quality variable fertilization operations, but the detection accuracy of existing fertilizer discharge volume detection systems is greatly disturbed by the noise of field operations. This paper develops an efficient algorithm for converting fertilizer point cloud data into fertilizer volume (P&V Algorithm) by proposing two assumptions that can be used as the basis for the calculation of fertilizer volume: (I. the overall volume of fertilizer is not affected by the field environment. II. The area of change in the geometric characteristics of fertilizer can fully reflect the volume change), and then a new fertilizer volume detection system is designed (P＆V System). The system realizes real-time acquisition of point cloud data of fertilizer geometry by integrating single-line LiDAR and other hardware. The algorithm uses escape value filtering, outlier removal, ordered point cloud set construction, and point cloud smoothing to achieve noise reduction of point cloud data, and uses dynamic region extraction to significantly reduce the computation amount, and transforms point cloud data into volume efficiently by improving Delaunay triangulation division, and then calculates the mass of fertilizer discharge. The test results showed that the measurement error (ME) of the P&V system during field operation was 2.34–4.66% (N), 2.14–4.25% (K) and 1.87–4.59% (P) when the fertilizer drain speed was in the range of 20r/min-70r/min, and there was no significant difference between the detected values of the system and the actual mass of fertilizer discharged (P > 0.01). Under the same field operation conditions, the ME of P&V System was significantly lower than that of the conventional fertilizer apparatus speed detection technology (P < 0.01) and the common fertilizer flow detection technology (P < 0.01). The research results of this paper can provide a new solution for the research of fertilizer discharge detection technology. [ABSTRACT FROM AUTHOR]