No abstract

The fluidity and filling ability of glass-forming Zr-based alloy melt in copper mould were investigated both theoretically and experimentally. The major factors which affected the flowing behavior of the metallic melt in the mold were determined, which provides the foundation for overcoming the contradiction between the filling and formation of amorphous alloy during the rapid cooling process of the metallic melts. The casting factors to prepare a metallic ring were discussed and selected. As a result, a Zr-based bulk metallic glass ring was prepared successfully.Zr-based bulk metallic glass, casting, fluidity, moldingThe earliest amorphous alloy was discovered in the 1960s by quenching Ag 80 Si 20 melt [1] . Due to the limitation of the cooling rate, amorphous alloys can only be made in the form of ribbons and powders which limit the application severely in the earlier years. Since the discovery of La-based and Zr-based bulk metallic glass (BMG) systems [2][3][4][5] by Inoue and Johnson respectively, the limitation of cooling rate was broken up. Later, the Pb 40 Cu 30 Ni 10 P 20 bulk amorphous alloy with a thickness of 72 mm was made by replacing Ni in Pb 40 Ni 40 P 20 by 30% Cu in Inoue's group [6] . The critical cooling rate was measured to be only about 0.33 K/s by Johnson's group [7] . The above mentioned research tremendously contributed to the preparation of BMGs in a large size.Due to the special structure of BMGs, BMGs have different properties from conventional crystalline alloys, such as high strength, high hardness, high elastic limitation and high fracture toughness, and superplasticity in a supercooled liquid region. Meanwhile, BMGs also have other favorable properties such as wear resistance, corrosion resistance, radialization resistance and antioxidation. These properties attract extensive attention in the metallic materials field [8][9][10] . In

We report the anharmonic effect of the Raman-scattering spectrum in the low-carrier density superconductor SrxBi2Se3, which is dominated by the quartic term. Compared to the parent Bi2Se3, the superconducting SrxBi2Se3 crystals show obvious phonon softening in the three optical phonon modes , , and . Based on the simulations by the Fano function, we present compelling evidence of the enhanced electron–phonon coupling in SrxBi2Se3 for its smaller asymmetric parameter q. Moreover, an anomalous broadening and intensity antiresonance in the characteristic Raman peaks were observed as the temperature decreased to around 160 K. Thus, the superconducting topological material SrxBi2Se3 represents a counterintuitive example where the electron–phonon interaction is strengthened by the accumulation of electron carriers.

Understanding the fundamental principle of catalytic performance and the mechanism of multimetal-based electrocatalysts is essential for the rational design of advanced renewable energy systems. Here, the highly crystalline MMMoB4 (M=Fe,...

The low-voltage switching devices are widely used in all aspects of the power system. It is essential to verify performance after design, manufacture or repair. In our national standards and the international IEC standard, short-circuit test of the electrical products for use in the power system is very important, so it is necessary to research and develop the shortcircuit test equipment and this issue was of course paid much attention by domestic and foreign researchers. In the process of the research and manufacturing of the short-circuit test equipment, the calculation of the expected output current is an essential part. In this paper, the expected short-circuit current of the test equipment is computed and simulated. Firstly, the impedances of the test system are calculated, then the model is created. From the quantified calculation results, the influencing factors which differentiate the actual output current from the expected value are analyzed. The results provide a theoretical basis for the development of this new test apparatus.