Oxide removal from Ge(100) surfaces treated by HCl and HF solutions with different concentrations are systematically studied by synchrotron radiation photoelectron spectroscopy (SR-PES). SR-PES results show that clean surfaces without any oxide can be obtained after wet chemical cleaning followed by vacuum annealing with a residual carbon contamination of less than 0.02 monolayer. HF etching le...

A controllable flower-like Au nanostructure array for surface-enhanced Raman scattering (SERS) was fabricated using the combined technique of the top-down approach of conventional photolithography and the bottom-up approach of electrodeposition. Au nanostructures with a mean roughness ranging from 5.1 to 49.6 nm were obtained by adjusting electrodeposition time from 2 to 60 min. The rougher Au ...

We report on the first results of experiments to measure the recombination rate of hydrogen on surfaces of astrophysical interest. Our measurements give lower values for the recombination efficiency (sticking probability S x probability of recombination upon H-H encounter γ) than model-based estimates. We propose that our results can be reconciled with average estimates of the recombination rat...

The structural and morphological characteristics of visible-light-emitting porous Si layers produced by anodic and stain etching of single-crystal Si substrates are compared using transmission electron microscopy and atomic force microscopy ( AFM) . AFM of conventionally anodized, laterally anodized and stain-etched Si layers show that the layers have a fractal-type surface morphology. The anod...

Spontaneous stratification of granular mixtures has been reported by Makse et al. @Nature ~London! 386, 379 ~1997!# when a mixture of grains differing in size and shape is poured in a quasi-two-dimensional heap. We study this phenomenon using two different approaches. First, we introduce a cellular automaton model that illustrates clearly the physical mechanism; the model displays stratificatio...

Redox potential (Eh) control plays a significant role during sulfide mineral flotation by influencing the reactions on surface of minerals and accordingly behaviour. In this study, metallurgical performance typical copper minerals, molybdenite as well gangue (e.g., pyrite, tennantite, enargite) under different pH Eh conditions cell were investigated. The molybdenum processing plant at Sungun co...

Water scarcity is compelling mining houses to not only recycle process water but also identify alternative sources of make-up in concentrators. South Africa has significant volumes acid mine drainage (AMD) generated from vast operations. This study investigated the viability using AMD as a replacement for potable flotation platinum-group-minerals (PGM)-bearing Merensky ore. Rougher and cleaner ...