Abstract
The action of Ar/O
2
plasmas with proteins is mimicked by employing a particle beam experiment with individually controllable and absolutely calibrated sources of O atoms/O
2
molecules and ...of argon ions. It is demonstrated that beams of thermal O atoms and of O
2
molecules with fluences up to
j
O
= 8.6 × 10
18
cm
−2
and
j
O2
= 5.4 × 10
20
cm
−2
have no measurable effect on the proteins at room temperature, whereas the combination of an O/O
2
beam and of an 100 eV Ar
+
ion beam induces very efficient protein removal, which is accompanied by a significant increase of their surface roughness. These observations are attributed to the process of chemical sputtering caused by the simultaneous impact of incident radicals and energetic ions.
magnified image
The accurate calculations of neutron-induced reaction cross sections are relevant for many nuclear applications. The photon strength functions and nuclear level densities are essential inputs for ...such calculations. These quantities for
235
U are studied using the measurement of the gamma de-excitation cascades in radiative capture on
234
U with the Total Absorption Calorimeter at n_TOF at CERN. This segmented 4π gamma calorimeter is designed to detect gamma rays emitted from the nucleus with high efficiency. This experiment provides information on gamma multiplicity and gamma spectra that can be compared with numerical simulations. The code DICEBOXC is used to simulate the gamma cascades while GEANT4 is used for the simulation of the interaction of these gammas with the TAC materials. Available models and their parameters are being tested using the present data. Some preliminary results of this ongoing study are presented and discussed.
The accurate calculations of neutron-induced reaction cross sections are relevant for many nuclear applications. The photon strength functions and nuclear level densities are essential inputs for ...such calculations. These quantities for 235U are studied using the measurement of the gamma de-excitation cascades in radiative capture on 234U with the Total Absorption Calorimeter at n_TOF at CERN. This segmented 4π gamma calorimeter is designed to detect gamma rays emitted from the nucleus with high efficiency. This experiment provides information on gamma multiplicity and gamma spectra that can be compared with numerical simulations. The code DICEBOXC is used to simulate the gamma cascades while GEANT4 is used for the simulation of the interaction of these gammas with the TAC materials. Available models and their parameters are being tested using the present data. Some preliminary results of this ongoing study are presented and discussed.
Metallocene catalysts have opened a new era for olefin polymerization with the promise of rational catalyst design to optimize new systems or to afford previously unknown polymer structures. This ...chapter provides examples that demonstrate that there is a great deal of flexibility and much is being learned about the relationship between the metallocene structure and polymerization performance. Interest in olefin polymerization using cationic metallocene complexes continues to increase very rapidly. This phenomenon is reflected in the number of patents, publications, and conferences dealing with this vast growing field. Work in this area, especially for zirconocene/methylaluminoxane (or other ion pair co-catalyst systems) catalysts is beginning to see commercial development and application. The chapter brings out some of the differences; between the two metallocene systems.
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