Ultra-High Vacuum Techniques

Rolling Contact Fatigue in Ultra High Vacuum

Direct-write polymer nanolithography in ultra-high vacuum

Polymer nanostructures were directly written onto substrates in ultra-high vacuum. The polymer ink was coated onto atomic force microscope (AFM) probes that could be heated to control the ink viscosity. Then, the ink-coated probes were placed into an ultra-high vacuum (UHV) AFM and used to write polymer nanostructures on surfaces, including surfaces cleaned in UHV. Controlling the writing speed...

Selective Hydrogenation of Acetylene over Palladium in Ultra High Vacuum

Under ultra-high-vacuum conditions, precoverage of a palladium(ll1) surface with hydrogen does not affect either the kinetics or the extent of acetylene uptake at 175 K. The subsequent reactive behavior of the system is however radically altered. Benzene formation is strongly suppressed, the transformation of adsorbed acetylene to another species (@-phase) is enhanced, and the yield of ethylene...

Ultra - high field imaging techniques for MRA

• Performing magnetic resonance angiography (MRA) at higher fields has been demonstrated to improve the signal to noise and contrast to noise in both the brain and body applications. • Direct implementation of standard clinical protocols and acquisitions methods at 7T are insufficient to obtain the best results as increased B0 and B1+ inhomogeneity, local SAR and limited peak power present road...

corneal endothelial cell loss after phacoemulsification in relation to hydrodynamic parameters: low versus high vacuum techniques

purpose: to evaluate the effect of vacuum and flow rate on endothelial cell loss after high versus low vacuum phacoemulsification. methods: this randomized clinical trial was performed on 60 eyes of 60 patients with moderate lens opacity (nuclear sclerosis 3+). all surgeries were performed by one experienced surgeon using stop and chop technique with sovereign white star machine (amo). patients...