Vacuum energy observation operators

The operator (175) measures the energy of a given state with respect to the vacuum IO5) in the presence of the external potential. In the noninteracting situation these energy differences correspond directly to the observable ionization potentials. However, the operator (175) does not yet reflect the fact that the vacuum energies resulting from different external potentials are not identical (Casimir effect). The differences between the vacua are most easily seen on a local scale The vacuum expectation value of the current density operator (7) reads... 

Thermal ionization mass spectrometry (TIMS) is one of the oldest mass spectrometric techniques, first applied by Dempster in 1918.114 The thermal emission of positivly charged ions emitted from a salt on a heated surface was first observed by Gehrcke and Reichenheim 12 years before.115 The thermal surface ionization source is a very simple ion source and operates under high vacuum conditions. TIMS is mostly useful for elements with relatively low ionization energy ( )) - in... 

Samples for SEM observations were air dried and mounted on 2.54 cm alununum pin-type stubs which had been previously coated with carbon paint. Mounted samples were coated with approximately 10 nm of spectroscopically pure carbon in an Edwards 505 vacuum evaporator and examined with an AMRay 1600T SEM operated at 15 kV. Energy dispersive X-ray spectrometry was performed with a Kevex 0700 system spectra were collected for 200 seconds at 15 kV and analyzed with Kevex s standardless routine with ZAF corrections by MAGIC V. 

The observed behavior in the yield of middle distillates and vacuum gas oil may explain why there is an increase in the total liquid recovery of the product with boiling temperatures above 300°C. It also implies that vacuum gas oil is more feasible to hydrocrack than the middle distillates fraction. The yield of gases does not change substantially at the operating conditions studied and remains almost in the same low limits. This is probably due to the fact that the activation energy to hydrocrack the light fractions such as naphtha has not been reached. 

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