Platinum and Palladium in Coal Rock and Geochemical Anomaly in Eastern Yunnan Province,Southwest China

A series of geochemical anomalies of Pt and Pd were found in 1 358 recombined samples from a geochemical stream sediment survey in eastern Yunnan （云南） Province, China. Chemical optical emission spectroscopy, X-ray fluorescence analysis, and inductively coupled plasmas atomic emission spectrometry analyses of 22 elements and chemical compositions of 21 samples from coal-bearing strata from the Late Paleozoic, Mesozoic, and Cenozoic show Pt and Pd concentrated to some extent in coal rocks, with Pd/Pt〈1. As, Pt, B, Au, Pd, V, Sb, U, Pb, and W are enriched in the Lower Carboniferous coal-bearing strata of the Wanshoushan （万寿山） Formation; B, Mo, As, Pt, U, W, Pb, Pd, and V are enriched in the Lower Permian coal-bearing strata of the Liangshan （梁山） Formation; Pt, Cu, Mo, Pd, As, V, and Ag are enriched in the Upper Permian coal-bearing strata of the Xuanwei （宣威） Formation; As, B, Pb, Pt, Pd, U, W, Sb, Mo, Zn, and Ag are enriched in the Upper Triassic coal-bearing strata of the Xujiahe （须家河） Formation; and Pt, As, and Pb are enriched in the lignite of the Pliocene Ciying （茨营） Formation. Combining analyses of the sedimentary environment and local volcanic activity reveal that the coalbearing strata in the Xuanwei Formation are possibly related to the Permian Emeishan （峨眉山） basalt.

A novel hybrid method for aerodynamic noise prediction of high-lift devices

Aerodynamic noise of High-Lift Devices(HLDs)is one of the main sources of airframe noise,and has immediate impacts on the airworthiness certification,environmental protection and security of commercial aircraft.In this study,a novel hybrid method is proposed for the aerodynamic noise prediction of HLD.A negative Spalart-Allmaras(S-A)turbulence model based Improved Delayed Detached Eddy Simulation(IDDES)method coupling with AFT-2017b transition model is developed,in order to elaborately simulate the complex flow field around the HLD and thus obtain the information of acoustic sources.A Farassat-Kirchhoff hybrid method is developed to filter the spurious noise sources caused by the vortex motions in solving the Ffowcs Williams-Hawkings(FW-H)equation with permeable integral surfaces,and accurately predict the far-field noise radiation of the HLD.The results of the 30P30N HLD indicate that,the computational Sound Pressure Levels(SPLs)obtained by the Farassat-Kirchhoff hybrid method conform well with the experimental ones in the spectrum for the given observation point,and are more accurate than those obtained by the Farassat 1A method.Based on the hybrid method,the acoustic directivity of the HLD of a commercial aircraft is obtained,and the variation of the SPLs in the spectrum with the deflection angle of the slat is analyzed.