Search results for "vacuum"
showing 10 items of 352 documents
High magnetic fields for fundamental physics
2018
Various fundamental-physics experiments such as measurement of the birefringence of the vacuum, searches for ultralight dark matter (e.g., axions), and precision spectroscopy of complex systems (including exotic atoms containing antimatter constituents) are enabled by high-field magnets. We give an overview of current and future experiments and discuss the state-of-the-art DC- and pulsed-magnet technologies and prospects for future developments.
Application of an O-ring pinch device as a constant-pressure inlet (CPI) for airborne sampling
2020
We present a novel and compact design of a constant-pressure inlet (CPI) developed for use in airborne aerosol mass spectrometry. In particular, the inlet system is optimized for aerodynamic lenses commonly used in aerosol mass spectrometers, in which efficient focusing of aerosol particles into a vacuum chamber requires a precisely controlled lens pressure, typically of a few hectopascals. The CPI device can also be used in condensation particle counters (CPCs), cloud condensation nucleus counters (CCNCs), and gas-phase sampling instruments across a wide range of altitudes and inlet pressures. The constant pressure is achieved by changing the inner diameter of a properly scaled O-ring that…
Diamond nucleation on iridium: local variations of structure and density within the BEN layer
2009
Abstract The diamond nuclei generated by the bias enhanced nucleation (BEN) on iridium are gathered in well defined areas (“domains”). In atomic force microscopy (AFM) measurements they become manifest in a 1 nm downward step. The fine structure of the carbon layer inside and outside these domains has been studied by small spot Auger electron spectroscopy (AES), high resolution transmission electron microscopy (HRTEM), AFM and lateral force microscopy (LFM). The Auger spectra of the carbon KLL peak taken in an ultra high vacuum setup revealed diamond features inside and more graphitic features outside the domains. The comparison with the intensity of the Auger signal originating from the un…
Interdisciplinary consensus on the uses and technique of MR-guided vacuum-assisted breast biopsy (VAB): results of a European consensus meeting.
2009
Abstract Purpose Quality assurance of MR-guided vacuum-assisted breast biopsy (VAB). Method A consensus was achieved based on the existing literature and experience of an interdisciplinary group comprising European specialists in breast imaging and VAB. Results Full imaging work-up must be completed according to existing standards before an indication for MR-guided VAB is established. The procedure should be reserved for lesions demonstrable by MRI alone. Acquisition of >24 cores (11-Gauge) should be routinely attempted, with the intention of sufficiently removing small lesions for accurate diagnosis. Following biopsy the patient should be re-imaged to demonstrate the biopsy site and its pr…
Laser-induced plasma spectroscopy in near vacuum ultraviolet using ordinary spectrograph and ICCD
2002
An experimental setup to measure laser-induced plasma emission spectra with an ordinary Czerny-Turner spectrograph and intensified charge-coupled device in the near vacuum ultraviolet down to 130 nm is described. Spectra of bromine, chlorine and iodine were recorded to demonstrate the performance of the setup.
Effects of packaging on shelf-life and quality of minimally processed fennel
2018
Fennel is not a widespread product among minimally processed vegetables, due to the fast deterioration mainly caused by browning of the cut surfaces, even during cold storage. In order to extend the shelf-life of fresh-cut fennel, the influence of different packaging techniques was studied. Sliced fennel, dipped in a citric acid solution (0.5%), was placed in polystyrene trays, sealed with PE film or vacuum packaged in PE bags and stored up to 14 days at 4°C. During this period the weight loss, soluble solid content, pH, color and firmness were evaluated. Minimally processed fennel packed in sealed trays and cold-stored at 4°C, extended its shelf-life to 14 days maintaining acceptable quali…
Electrodeless HF-lamps as UV and VUV light sources
2002
The paper is devoted to problems of employment of high- frequency electrodeless lamps as ultra violet (UV) and vacuum ultra violet (VUV) light sources. Some aspects of lamp preparation technology for UV and VUV are considered. The technology, developed in our laboratory, allows to prepare HFEL-s filled with wide spread of chemical elements. Our experience shows that most important filling elements for UV and VUV spectral regions are Zn, Cd, Hg, Se, As, Sn and Pb, Sb, Bi, Tl, Te, I, H, Hg-Cd, Hg-Zn, Se-Te. The requirements for generators are discussed. Some important spectral characteristics of lamp examples are presented.
Monitoring the chemical changes in Pd induced by hydrogen absorption using microcantilevers.
2003
Abstract The reactivity of the palladium shaped as a microcantilever is investigated as a function of the hydrogen stoichiometry. A small cell holding the microcantilever is designed to monitor the deflection and the flexural resonance response from high vacuum to a hydrogen gas pressure of several bars. The measurements show that the Young's modulus is accurate if the cantilever is thick enough to be described by a continuum mechanics approach. The orientation distribution function of the palladium grains determined by X-ray diffraction enables to correlate Young's modulus measured using microcantilevers with the elastic constant tensor issued from the literature. The surface stress induce…
A microscopic approach to Casimir forces between metal bodies
2014
We consider the Casimir interaction between macroscopic metallic objects in terms of the dispersion interactions (Casimir-Polder and van der Waals) between their constituents. Expressions for two- and three-body dispersion interactions between the microscopic parts of a metal are obtained, both in the retarded and non-retarded limits. They are then used to evaluate two- and three-body contributions of the Casimir force between two flat ideal metallic slabs. Our results show the non-applicability of the Hamaker approximation in this geometry. It is further seen that the three-body contributions give an overall repulsive contribution to the force, which is of the same order of magnitude as th…