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Strong magnetic fields are required in many fields, such as medicine (magnetic resonance imaging), pharmacy (nuclear magnetic resonance), particle accelerators (such as the Large Hadron Collider) and fusion devices (for example, the International Thermonuclear Experimental Reactor, ITER), as well as for other diverse scientific and industrial uses. For almost two decades, 45 tesla has been the highest achievable direct-current (d.c.) magnetic field; however, such a field requires the use of a 31-megawatt, 33.6-tesla resistive magnet inside 11.4-tesla low-temperature superconductor coils.sup.1, and such high-power resistive magnets are available in only a few facilities worldwide.sup.2. By contrast, superconducting magnets are widespread owing to their low power requirements. Here we report a high-temperature superconductor coil that generates a magnetic field of 14.4 tesla inside a 31.1-tesla resistive background magnet to obtain a d.c. magnetic field of 45.5 tesla--the highest field achieved so far, to our knowledge. The magnet uses a conductor tape coated with REBCO (REBa.sub.2Cu.sub.3O.sub.x, where RE = Y, Gd) on a 30-micrometre-thick substrate.sup.3, making the coil highly compact and capable of operating at the very high winding current density of 1,260 amperes per square millimetre. Operation at such a current density is possible only because the magnet is wound without insulation.sup.4, which allows rapid and safe quenching from the superconducting to the normal state.sup.5-10. The 45.5-tesla test magnet validates predictions.sup.11 for high-field copper oxide superconductor magnets by achieving a field twice as high as those generated by low-temperature superconducting magnets. A copper oxide high-temperature superconductor magnet generates a direct-current magnetic field of 45.5 tesla--the highest value reported so far--using a design that enables operation at high current densities., Author(s): Seungyong Hahn [sup.1] [sup.2] , Kwanglok Kim [sup.1] , Kwangmin Kim [sup.1] , Xinbo Hu [sup.1] , Thomas Painter [sup.1] , Iain Dixon [sup.1] , Seokho Kim [sup.1] [sup.3] [...]

The alloy-reinforced Bi-2223 composite tapes can be used to realize high-magnetic field magnets, and its equivalent mechanical properties are important because of the great stress during the manufacturing and operation of magnets. Since the alloy-reinforced Bi-2223 tape has a complex structure, suitable analytical methods and equivalent models are necessary. The analysis of the equivalent mechanical properties is achieved by the mixture rule method and finite element simulation of simplified models. By using different simplified models, it is found that the single-filament elliptical model reduced computation time at most compared with the multi-filaments model, while the deviation from the experimental results is the minimum. It also shows that the details of the geometry in the models have little effect on the results. The results of the mixture rule method also agree with the experimental results, demonstrating that using the mixture rule method and simulation method of a single-filament elliptical model for mechanical analysis of alloy-reinforced Bi-2223 tapes is feasible. [ABSTRACT FROM AUTHOR]

This study discusses the way to improve the efficiency of high learning teaching based on information fusion technology. First, it analyzes the current situation and challenges of university teaching, and the application of information fusion technology in education. Then, the general situation of information fusion technology and the basic principle of factor analysis and its application in education research are introduced in detail. Through factor analysis, this study finds out and summarizes the key factors affecting the efficiency of high school teaching, and builds a factor analysis model suitable for high school teaching. Based on this, it puts forward some promotion strategies such as optimizing teaching content and methods, strengthening teachers’ role and ability, cultivating students’ learning ability and interest, and improving evaluation mechanism and feedback system. Through the actual case analysis, the effectiveness of the path of improving high learning teaching efficiency based on information fusion technology is verified. Finally, the practical significance of this study is summarized, and the limitations and future research directions are pointed out. [ABSTRACT FROM AUTHOR]

Using ferric chloride as an oxidant, here, we investigated the leaching effect of low-nickel matte in a flow field produced by mechanical agitation. The factors affecting a leaching reaction, such as stirring speed, leaching time, low-nickel matte particle size, and inert abrasive quartz sand, were studied. X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), a laser particle size analyzer, optical microscopy (OM), a scanning electron microscopy (SEM) with an energy dispersive X-ray detector (EDS), and a Raman spectrometer were used to characterize the materials before and after the leaching reaction. The contents of the main metal ions such as Ni, Cu, and Co in the leaching solution were analyzed by inductively coupled plasma atomic emission spectroscopy (ICP-AES). Using the control variable method, the optimal experimental conditions were as follows: 2 mol/L FeCl3—0.5 mol/L HCl-H2O system with low-nickel matte and quartz sand (mass ratio is 1:5) and leaching at 90 °C for 8 h. The results showed that the blocking effect of the solid product sulfur layer was effectively removed and continuous leaching was realized. The leaching efficiencies of Ni, Cu, and Co were 98.9%, 99.3%, and 98.1%, respectively. [ABSTRACT FROM AUTHOR]