Spectroscopic Features and Formation Conditions of Sphalerite in the Lead-Zinc Deposit, Guangdong,China

Electron paramagnetic resonance spectra, absorption spectra, cathodoluminescence spectra and infrared spectra of sphalerite from the Lechang remoulded sedimentary lead-zinc deposit have been studied so as to provide microscopic evidence for the formation conditions and mineralization stages of the deposit as well as the geochemical processes of mineralization. On the basis of thermodynamic calculations, the stable fields of sphalerite from different mineralization stages were determined and are shown in logfs_2-logfo_2 diagrams; furthermore. the physico-chemical conditions of mineralization and the properties of mineralization solutions are discussed so that reliability of the genetic information provided by the spectroscopy of sphalerite may also be verified. It is suggested that the temperature and pH value of the mineralization system decrease, and so do the fugacities of O_2, S_2, H_2. and H_2S and the activities of HS^- and SO_4^(2-) from the early to late stages of minerahzation.

Iris Liveness Detection Using Fragmental Energy of Haar Transformed Iris Images Using Ensemble of Machine Learning Classifiers

Contactless verification is possible with iris biometric identification,which helps prevent infections like COVID-19 from spreading.Biometric systems have grown unsteady and dangerous as a result of spoofing assaults employing contact lenses,replayed the video,and print attacks.The work demonstrates an iris liveness detection approach by utilizing fragmental coefficients of Haar transformed Iris images as signatures to prevent spoofing attacks for the very first time in the identification of iris liveness.Seven assorted feature creation ways are studied in the presented solutions,and these created features are explored for the training of eight distinct machine learning classifiers and ensembles.The predicted iris liveness identification variants are evaluated using recall,F-measure,precision,accuracy,APCER,BPCER,and ACER.Three standard datasets were used in the investigation.The main contribution of our study is achieving a good accuracy of 99.18%with a smaller feature vector.The fragmental coefficients of Haar transformed iris image of size 8∗8 utilizing random forest algorithm showed superior iris liveness detection with reduced featured vector size(64 features).Random forest gave 99.18%accuracy.Additionally,conduct an extensive experiment on cross datasets for detailed analysis.The results of our experiments showthat the iris biometric template is decreased in size tomake the proposed framework suitable for algorithmic verification in real-time environments and settings.

中国浙江丹霞拱形岩穴与美国科罗拉多高原天然石拱和天生桥特征与成因的对比研究

The red beds in Zhejiang province of China host the highest concentration of Danxia arched rock shelters in the world,just as the Colorado Plateau in the western USA hosts the world's largest concentration of natural arches and bridges.This study investigated the geological background of the arched rock shelters and compared them to the natural arches and bridges,based on field study and a literature review.It was found that Zhejiang arched rock shelters differ from Colorado Plateau natural arches and bridges in geometry and formation mechanism.Statistical geometric data on arch geometry shows that Danxia arched rock shelters in Zhejiang tend to be relatively flat.They are relatively low features with long spans,and great depth.The natural arches and bridges on the Colorado Plateau are similar to each other,but the bridges are larger than the arches.The geometric differences between the arched landforms could be attributed to their different geologic history and to their different formation mechanisms.The arched rock shelters in Zhejiang are formed by differential weathering between sandstone and conglomerate due to moisture-induced tensile stresses.In contrast,natural arches on the Colorado Plateau are closely related to the Salt Valley anticline,vertical tectonic fractures,and horizontal discontinuities in rock fins.The Colorado Plateau natural bridges were formed by river erosion.