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Full-Text Articles in Physics
Characterisation Of The Effects Of Time And Pressure On A Group Of Electronic Voltage Standards, James Kevin Armstrong
Characterisation Of The Effects Of Time And Pressure On A Group Of Electronic Voltage Standards, James Kevin Armstrong
Masters
Although primary metrology laboratories use standards based on the Josephson effect to maintain a local reference standard for dc voltage, artefact standards are still the standard of choice in many secondary laboratories. The National Metrology Laboratory, Dublin maintains a local reference standard for dc voltage by means of an ensemble of Zener-diode based electronic voltage standard units. Electronic voltage standards have a number of shortcomings over Josephson standards for use as a local reference standard. In particular their output voltages are influenced by several external factors. In order to make optimum use of the NML reference standard it is important …
The Design And Construction Of An Out-Of-Plane Sensitive Electronic Speckle Pattern Interferometer For Non-Destructive Testing Applications, Alexander Burden
The Design And Construction Of An Out-Of-Plane Sensitive Electronic Speckle Pattern Interferometer For Non-Destructive Testing Applications, Alexander Burden
Masters
There are many non-destructive testing (NDT) techniques use din industry, which employ acoustic emission, ultrasound, X-rays and thermography. Optical interferometric methodology is being increasingly used in industry. Electronic Speckle Pattern Interferometry (ESPI) is one of the principal optical interferometric techniques used in NDT to measure deformations. Optical surface metrology offers many advantages over conventional methods. These include greater sensitivity, improved lateral and vertical resolution, non-contact and full field measurement. Conventional methods of NDT however continue to be chosen over ESPI. The objective of this thesis is focused on making ESPI more feasible as a NDT technique for use in industry. …
Temperature Dependence Of Stark Width Of The 463.054 Nm Nii Spectral Line, Vladimir Milosavljevic, Ruzica Konjevic, Stevan Djenize
Temperature Dependence Of Stark Width Of The 463.054 Nm Nii Spectral Line, Vladimir Milosavljevic, Ruzica Konjevic, Stevan Djenize
Articles
Stark width of the 463.054 nm singly ionized nitrogen spectral line, that belong to transition, have been measured in a linear pulsed, low pressure, arc discharge. The working gas was helium-nitrogen-oxygen mixture. Electron densities of 0.751023 to 1.451023 were determined in the electron temperature range between 30000 K - 38000 K. The measured values have been compared with our calculated data, using the modified semiempirical approximation. On the basis of the agreement among experimental and theoretical Stark width data, the isolated 463.054 nm NII spectral line can be recommended as convenient spectral line for plasma diagnostics.
Experimental Observation Of Individual Single Wall Nanotube Species By Raman Microscopy, G. S. Duesberg, W. Blau, Hugh Byrne, J. Muster, M. Burghard, S. Roth
Experimental Observation Of Individual Single Wall Nanotube Species By Raman Microscopy, G. S. Duesberg, W. Blau, Hugh Byrne, J. Muster, M. Burghard, S. Roth
Articles
Individual single-wall carbon nanotubes (SWNT) or small ropes of SWNTs with the same diameter have been characterised by Raman spectroscopy. Highly pure, length-selected SWNTs adsorbed onto substrates designed for surface-enhanced Raman spectroscopy were investigated with a Raman microscope. Various spectra, each with a distinct sharp peak in the radial breathing mode area and four C–C stretching modes could be observed. The modes also showed a strong variation in the relative intensities. In correlation with theoretical predictions this should establish Raman microscopy as a non-destructive nano-technological tool, capable of determining the diameter, symmetry and position of individual SWNTs.