Gas-liquid flows abound in a great variety of industrial processes. Correct recognition of the regimes of a gasliquid flow is one of the most formidable challenges in multiphase flow measurement. Here we put forward a novel approach to the classification of gas-liquid flow patterns. In this method a flow-pattern map is constructed based on the average energy of intrinsic mode function and the volumetric void fraction of gas-liquid mixture. The intrinsic mode function is extracted from the pressure fluctuation across a bluff body using the empirical mode decomposition technique. Experiments adopting air and water as the working fluids are conducted in the bubble, plug, slug, and annular flow patterns at ambient temperature and atmospheric pressure. Verification tests indicate that the identification rate of the flow-pattern map developed exceeds 90%. This approach is appropriate for the gas-liquid flow pattern identification in practical applications.

The β phase (Al ₁₂Mg ₁₇) precipitated by heat treatment in some alloy compositions may result deterioration of corrosion resistance. However, much of its role remains unclear. The effect of the β phase on the corrosion resistance behavior in a NaCl solution was presented in this study. The specimen was Mg-9mass%Al (AM90) alloy and the content of the β phase precipitant was controlled systematically by aging time at 473 K. Area rate of β and lamellar phase in the specimens were 0, 10 and 100%, respectively. According to the results of cathodic polarization curves measurement, the corrosion current density of α phase was 0.215 A/m2 and β phase of it was 0.096 A/m2. While, the specimen includes 10% of β and lamellar phase showed large corrosion current density of 0.251 A/m2. Positive correlation between the β phase and the open circuit potential, suggest that the β phase acts as a cathodic electrode. Moreover, the microstructure after postentiostatic corrosion tests was also support the role of β phase.