About the new version of ISO/IEC 17025

This article outlines the general concept of ISO/IEC 17025 that can help laboratories demonstrate their ability to provide reliable results. The most significant changes in 17025: 2017 are reviewed

Zettawatt-Exawatt Lasers and Their Applications in Ultrastrong-Field Physics: High Energy Front

Since its birth, the laser has been extraordinarily effective in the study and applications of laser-matter interaction at the atomic and molecular level and in the nonlinear optics of the bound electron. In its early life, the laser was associated with the physics of electron volts and of the chemical bond. Over the past fifteen years, however, we have seen a surge in our ability to produce high intensities, five to six orders of magnitude higher than was possible before. At these intensities, particles, electrons and protons, acquire kinetic energy in the mega-electron-volt range through interaction with intense laser fields. This opens a new age for the laser, the age of nonlinear relativistic optics coupling even with nuclear physics. We suggest a path to reach an extremely high-intensity level $10^{26-28}$W/cm$^2$ in the coming decade, much beyond the current and near future intensity regime $10^{23}$W/cm$^2$, taking advantage of the megajoule laser facilities. Such a laser at extreme high intensity could accelerate particles to frontiers of high energy, tera-electron-volt and peta-electron-volt, and would become a tool of fundamental physics encompassing particle physics, gravitational physics, nonlinear field theory, ultrahigh-pressure physics, astrophysics, and cosmology. We focus our attention on high-energy applications in particular and the possibility of merged reinforcement of high-energy physics and ultraintense laser.Comment: 25 pages. 1 figur

On the design of experiments for the study of relativistic nonlinear optics in the limit of single-cycle pulse duration and single-wavelength spot size

We propose a set of experiments with the aim of studying for the first time relativistic nonlinear optics in the fundamental limits of single-cycle pulse duration and single-wavelength spot size. The laser system that makes this work possible is now operating at the Center for Ultrafast Optical Science at the University of Michigan. Its high repetition rate (1 kHz) will make it possible to perform a detailed investigation of relativistic effects in this novel regime. This study has the potential to make the field of relativistic optics accessible to a wider community and to open the door for real-world applications of relativistic optics, such as electron/ion acceleration and neutron and positron production.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45803/1/11452_2005_Article_253.pd

Spectroscopic Properties of Nanoceria Allowing Visualization of Its Antioxidant Action

Two distinct luminescence centers were revealed in ceria nanocrystals: first one – Ce3+ ions with 5d-4f luminescence at 390 nm, and second one – Ce4+–O2− complexes showing charge transfer (CT) luminescence at 630 nm. Intensity of Ce3+ luminescence depends directly on the concentration of oxygen vacancies in nanoceria and can be varied by means of change of both heat treatment atmosphere from oxidizing to reducing and the size of nanocrystal. Ce3+ luminescence can be used for visualization of the processes of interaction between ceria nanoparticles and reactive oxygen species using relative intensity of Ce3+ band as a measure of Ce4+/Ce3+ ratio during oxidation reaction.

Formation of luminescent centers in CeO2CeO{_2} nanocrystals

The nature of luminescence centers in CeO2 nanocrystals with varied oxygen stoichiometry has been investigated. It was shown that the luminescence of CeO2 is caused by the radiative relaxation in two different optical centers: the first one is Ce4+–O2− charge transfer state and the second one is Ce3+ ions. The ratio of Ce4+/Ce3+ centers depends on the amount of oxygen vacancies, therefore the variation of ceria stoichiometry allows changing the concentration of Ce4+–O2− and Ce3+ luminescence centers. Analysis of splitting of the excitation bands of Ce3+ luminescence has shown that oxygen vacancies in CeO2 nanocrystals are formed at the nearest-neighbor position to the cerium ion

Photocatalytic activity of ZnO nanopowders: The role of production techniques in the formation of structural defects

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