Based on the thermodynamic calculations, the universal secondary cooling structure, and the specific water rate for round blooms continuous casting in various diameters were investigated with a 2D heat transfer model. Results indicated that extension of the secondary cooling zone along casting direction significantly lowered the surface temperature recovery after the water cooling, though little influence on the recovering rate. The universal secondary cooling structure for the continuous casting of round blooms in diameters from 280 to 350 mm was optimized by appropriately extending the length of secondary cooling zone. The target unbending temperature was 908 °C for steel 16MnNb due to the thermodynamic calculation. To the optimized universal secondary cooling structure, the optimal specific water rates were 0.35 and 0.25 L kg−1 for the continuous casting of round blooms 280 and 350 mm in diameter, respectively. The present study had been applied to real production, resulting in round blooms in good quality, and contributing to the efficiency and flexibility of round blooms continuous casting process.

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In this paper, a broadband, low insertion loss, and compact folded substrate integrated waveguide (FSIW) phase shifter is proposed for the first time. By loading the complementary split-ring resonators (CSRRs) on the middle metal layer of the FSIW, a closed-type slow-wave transmission line (TL) is obtained, which can provide a wideband phase shift (39%) compared with the equal-length fast-wave one. The enclosed structure of the CSRR-loaded FSIW prevents the CSRRs from radiation as suffered in the previous reported CSRR-loaded TLs, resulting in a low insertion loss. This feature greatly reduces the amplitude imbalance between the main line and the reference line of the phase shifter. In addition, no transition structure is required between the FSIWs with and without CSRRs for broadband impedance matching, which makes the phase shifter more compact and easier to integrate with other FSIW devices. To validate the performance of the proposed phase shifter and to illustrate its ease integration, a novel FSIW 180° directional coupler that consists of an FSIW 90° coupler and an FSIW 90° phase shifter is designed, fabricated, and measured. The measured results agree well with the simulated data.

To investigate the variation of true density and the sulfur removal forms during the ultrahigh-thermal desulfurization process, two types of delayed petroleum cokes with different sulfur contents were calcined at temperatures up to 2500 °C at two distinct heating rates. The influence of the desulfurization coefficient on the true density growth was quantitatively discussed. Additionally, the removal forms of sulfur in petroleum cokes during thermal desulfurization were also investigated through a series of thermodynamic calculations. The results revealed a continuous increase in the true density with the uninterrupted release of sulfur during thermal desulfurization, and a maximum true density of 2.3 g/cm3 was obtained at a temperature of 2500 °C. The growth rate of the true density was dependent on the desulfurization coefficient of the petroleum cokes. The relationship between the true density growth rate and the desulfurization coefficient during thermal desulfurization was an exponential function, which can be presented as γTD = −117 × 10–5 exp­(−104βD–S/1.45) + 9.07 × 10–5. Furthermore, the calculated results indicated that gaseous elemental sulfur (S2) was released by the pyrogenic decomposition of ferrous disulfide into inorganic sulfur. Organic sulfur was initially degraded into H2S and SO2 through thiophene decomposition, and then free COS, S2, and CS2 were released via a carbon reduction reaction.

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