Search results for "beam [electron]"
showing 10 items of 433 documents
Charge dissipation in e-beam lithography with Novolak-based conducting polymer films
2008
Charging of common resist materials during electron beam (e-beam) writing leads to deflection of the electron beam path, which can result in significant pattern displacement. Here we report a new conducting polymer to eliminate charging. A common approach is to place the conducting layer underneath the e-beam resist layer. Conductivity equal or greater than 10(-4) S cm(-1) has been reported to prevent pattern displacement. Some other properties such as a flat surface layer, chemical inertness and insolubility in both the top resist solvent and the developer are also necessary. The way to achieve all these properties consisted in synthesizing a conducting polymer inside an insulating polymer…
Direct Surface Relief Formation in Polymer Films
2013
Due to active development of nanoelectronics, the studies of methods of nanorelief surface formation in different materials, in particular polymers are very important. Organic polymer films in consequence of their dielectric and optical properties have been used as basis of these devices. In this paper, the possibility of UV optical record and electron beam lithography in different type of polymeric films was studied. Mechanisms of molecular structure changes: photoisomerization, destruction, cross-linking and oxidation have been discussed. The results of UV illumination of polyurethanes, polyacrylates, and some block-copolymers were described. The element analysis of polybutadiene block co…
UV optical record and electron beam lithography in polymer films
2012
Possibility of UV optical record and electron beam lithography in different type of organic polymer films was studied. Mechanisms of molecular structure changes: photoisomerization, destruction, cross-linking and oxidation have been discussed. The results of UV illumination of polyurethanes, polyacrilates, and some block-copolymers are described. The element analysis of polyisoprene block copolymer was performed before and after UV illumination, and the changes in transmission spectra of the polymer film were measured. The resolution of electron beam lithography on polymer films was studied. In the polyisoprene block copolymer film the oxidation polymerization was ascertain at UV-illuminati…
Surface plasmon near-field imaging of very thin microstructured polymer layers.
2004
We report on the near-field imaging of microstructured polymer layers deposited on an homogeneous metal thin film on which a surface plasmon mode is excited. The microstructures in the polymer layers are designed by electron beam lithography, and the near-field imaging is performed with a photon scanning tunneling microscope (PSTM). We show that, despite their very small height, the microstructures can be conveniently imaged with a PSTM thanks to the field enhancement at the surface of the metal thin film supporting the surface plasmon. The influence of the illumination conditions on the contrast of the PSTM images is discussed. In particular, we show that both the field enhancement and the…
X-ray absorption near-edge structure of GaN with high Mn concentration grown on SiC.
2009
By means of x-ray absorption near-edge structure (XANES) several Ga(1-x)Mn(x)N (0.03x0.09) layers have been analyzed. The Mn-doped GaN samples consisted of different epilayers grown by molecular beam epitaxy on [0001] SiC substrates. The low mismatch between GaN and SiC allows for a good quality and homogeneity of the material. The measurements were performed in fluorescence mode around both the Ga and Mn K edges. All samples studied present a similar Mn ionization state, very close to 2+, and tetrahedral coordination. In order to interpret the near-edge structure, we have performed ab initio calculations using the full potential linear augmented plane wave method as implemented in the Wien…
Third molar surgical difficulty scales: systematic review and preoperative assessment form
2021
Background The main objective of this systematic review was to collect the pre-existing scales for assessing the difficulty of third molar extraction. The secondary objective was to design a proposal for a preoperative evaluation protocol for the difficulty of third molar extraction. Material and Methods Two independent researchers conducted an electronic search in Pubmed (MEDLINE), Cochrane, and Scopus databases during March 2021. Included studies evaluated the prediction of the difficulty of surgical removal of impacted upper or lower third molars using new indices/scales or pre-existing scales with or without modifications. Articles referring to coronectomies or assessing pre-surgical di…
A Theory for Multilayered Composite Beams
2014
Composite laminates are nowadays widely employed as lightweight components in civil engineering, automotive and aerospace applications due to their excellent mechanical properties, such as, the high strength and stiffness per unit weight, the path loads management capability. Moreover by using composite laminated materials it is possible to manufacture large size structures with less riveted joints, which leads to a reduction of the overall structural complexity and of the manufacturing and inspection times and costs. A drawback of layered composites is represented by the the low values of throughthe-thickness tensile and shear strengths, with respect to the in-plane ones, that affect the o…
Laser assisted decay spectroscopy at the CRIS beam line at ISOLDE
2012
A new collinear resonant ionization spectroscopy (Cris)beam line has recently been installed at Isolde, Cern utilising lasers to combine collinear laser spectroscopy and resonant ionization spectroscopy. The combined technique offers the ability to purify an ion beam that is heavily contaminated with radioactive isobars, including the ground state of an isotope from its isomer, allowing sensitive secondary experiments to be performed. A new programme aiming to use the Cris technique for the separation of nuclear isomeric states for decay spectroscopy will commence in 2011. A decay spectroscopy station, consisting of a rotating wheel implantation system for alpha decay spectroscopy, and thre…
Design and development of safety and control systems in ATLAS
2021
El gran colisionador de hadrones, o LHC, es el acelerador de partículas más grande y potente del mundo. Ha sido construido por el CERN, la Organización Europea para la Investigación Nuclear, entre 1998 y 2008 en Ginebra, Suiza. Sucesivas mejoras en el LHC supondrán a partir de mediados del 2027 un incremento de la luminosidad, cuando pasará a llamarse High Luminosity LHC (HL-LHC). Esta tesis se divide en dos partes, por una parte la seguridad y operación de la infraestructura y por otra los sistemas de control y toma de datos. La primera parte de la tesis se dedica a la seguridad y operación de la infraestructura. Después de más de 10 años de funcionamiento, el riesgo de posibles fallos en …
Prevalence and morphometric analysis of the retromolar canal in a Spanish population sample: a helical CT scan study.
2021
BACKGROUND: The retromolar canal (RMC) is an anatomical variation of the mandibular canal (MC) whose identification and study should be considered given its implication in the surgical procedures of the retromolar area. The prevalence of the RMC widely varies according to previous studies and may be influenced by the followed study method. This work aimed to evaluate the prevalence of the RMC in a Spanish population sample. MATERIAL AND METHODS: For this purpose, 225 CT scan images (with a higher resolution than the cone beam CT used in other previous studies) from the Hospital Clinico Universitario de Valencia were analyzed. The Osirix MD radiological image analysis system was applied to a…