Toroid-shaped soft magnetic powder cores (SMCs) were produced by cold pressing of the commercial sendust alloy powders. The characteristics of the commercial sendust alloy powder and the effect of compaction pressure on the magnetic properties, i.e., effective permeability μe, quality factor Q, DC-bias properties and volume power loss of sendust alloy powder cores were investigated. The results showed that the sendust alloy powder core with shaping pressure of 1932 MPa, annealing temperature of 953 K for 1 h and dielectric content of 0.96% presents the optimum magnetic properties with an effective permeability of 90, a total loss of 386 mW/cm3 at f=50 kHz and Bm=0.1 T, a DC-bias property of 64% at H=50 Oe.

Abstract. Rapidly quenched ribbons of Fe63.5Co10Si13.5B9Cu1Nb3alloy were annealed at 550°C in a vacuum for 1h and milled to powders. Cold-pressed nanocrystalline powder cores were fabricated using 1-5wt.% of epoxy E-44 as the binder and 1wt.% of Zn-stearate for lubrication under the pressure 155-200KN. The microstructure and morphology of powders were characterized with XRD and SEM. The effective permeability (μe) and quality factor (Q) were tested by using LCR HiTESTER 3532-50 in the range of 1–5000 kHz. The results show that the μe of the powder cores increased with the particle size. Powder cores with 2wt.% binder exhibited higher μe, but lower Q compared with samples with 3wt.% binder. Increase of the forming pressure helps improve μe, but the excessive stress caused by the forming pressure had a negative effect for μe.

A djustable ejector flow control can be achieved to export in a stable area, thus reducing the jet inlet parameters on the export parameters as well as the impact of the entire system, widening of the jet's effective operating range. In this paper, the establishment of an effective mathematical models and computational methods to commercial CFD software FLUENT 6.3 as a platform for the adjustable jet to simulate the internal flow process and performance research, exploration and analysis of the main needle is moved (ie the nozzle throat orifice area change) operating parameters (including the working fluid inlet pressure, inlet pressure and the lead body jet mixing fluid outlet pressure) on the adjustable jet performance of the law, for the adjustable jet to provide important parameters to optimize the design. Studies show that: ① the needle device with adjustable spray jet in a non-rated conditions, can increase the coefficient of the jet injector; ② other parameters remain the same circumstances, the adjustable jet to varying degrees, increased work pressure , suction pressure, discharge pressure and outlet flow range.