Search results for "ROTATIONAL"
showing 10 items of 381 documents
ALIGNEMENT UNI ET TRIDIMENSIONNEL DE MOLÉCULES PAR IMPULSION LASER FEMTOSECONDE
2007
This thesis is devoted to the study of the alignment of linear and asymmetric top molecules generated by an intense laser pulse. In the case of short pulses with respect to molecular rotation, periodic alignment appears in field-free conditions after the extinction of the field. We study theoretically and experimentally the effects of intensity, temperature and polarization of the electric field on produced alignment. If the field is linearly polarized, the interaction leads to the alignment of the most polarizable axis of the molecule. If the field is elliptically polarized, the pulse can generate a simultaneous alignment of the three principal axes of inertia of an asymmetric top molecule…
Reti sismiche urbane per monitoraggio sismico monitoraggio strutturale ed allerta precoce
2021
In questa tesi, viene effettuato un analisi preliminare in cui si mette in evidenza come l'italia sia un paese a rischio sismico, poichè possiede molti centri storici con strutture non progettate per eventi sismici di media entità. Si è prestato molta attenzione su quante vite umane vengono salvate dopo un terremoto catastrofico. L'analisi fa emergere come, è importante essere tempestivi nell'estrarre le persone rimaste sotto le macerie, poichè la percentuale di persone estratte vive si mantiene alta solo entro le 48 ore dall'evento. Dopo 96 ore questa percentule si attesta a 0. In eventi passati spesso i soccorsi sono arrivati con giorni di ritardo nelle zone più devastate. L'obbiettivo ch…
Metall-π-Komplexe von Benzolderivaten, XII Hyperfeinstruktur und Linienbreiten in den ESR-Spektren methylierter und deuterierter Bis(η-benzol)chrom(I…
1979
Die vollstandige Reihe der Methyl-Substitutionsprodukte des Bis(η-benzol)chrom(I)+·-Radikalkations sowie ausgewahlte deuterierte Derivate desselben wurden in Losung und in glasartig erstarrtem Medium ESR-spektroskopisch untersucht. 1H-, 2D- und 53Cr-Hyperfeinparameter werden mitgeteilt und das Proton/Deuteron-Kopplungskonstantenverhaltnis wird diskutiert. Die Betrage von a(1HAren) und a(1HMethyl) variieren innerhalb enger Grenzen (3,454,15 bzw. 0,50,7 G), wobei a(1HAren) mit zunehmendem Methylierungsgrad zunimmt. Um die Konformationsabhangigkeit von a(1HMethyl) zu studieren, werden die ESR-Spektren von (η12-[2.2]Paracyclophan)-chrom(I)+·, 21+·, und Bis(1,4-dimethyl-η6-benzol)chrom(I)+·, 5+·…
The Born–Oppenheimer equilibrium bond distance of GeO from millimetre- and submillimetre-wave spectra and quantum-chemical calculations
2014
The millimetre- and submillimetre-wave spectra of the five common isotopologues of (GeO)-O-16 in their electronic and vibrational ground state have been recorded in the spectral region 115-732GHz; for (GeO)-Ge-74-O-16, the rotational spectrum in the v = 1 state has been detected as well. Exploiting the high precision of the measurements, the Born-Oppenheimer breakdown parameter Delta(Ge)(01) could be determined from a Dunham analysis of the spectral data, whereas Delta(O)(01) was obtained from quantum-chemical calculations, because of the lack of high-precision measurements for the (GeO)-O-18 isotopologues. From the rotational equilibrium constant, the Born-Oppenheimer equilibrium distance …
Rotational spectrum of silyl chloride: hyperfine structure and equilibrium geometry
2012
The Lamb-dip technique was employed to record the rotational spectra of two isotopic species of silyl chloride, namely (28)SiH3Cl and (29)SiH3Cl, in order to investigate their hyperfine structure. High-accuracy quantum-chemical computations were employed to predict the hyperfine parameters involved and to support the experimental investigation. Analysis of the experimental spectra led to an improvement in the accuracy of the known spectroscopic constants as well as allowed us to determine additional spectroscopic parameters for the first time. Furthermore, the equilibrium structure of silyl chloride was reinvestigated using both theoretical and experimental data. The best theoretical and se…
A Marching in Space and Time (MAST) solver of the shallow water equations. Part I: The 1D model
2007
A new approach is presented for the numerical solution of the complete 1D Saint-Venant equations. At each time step, the governing system of Partial Differential Equations (PDEs) is split, using a fractional time step methodology, into a convective prediction system and a diffusive correction system. Convective prediction system is further split into a convective prediction and a convective correction system, according to a specified approximated potential. If a scalar exact potential of the flow field exists, correction vanishes and the solution of the convective correction system is the same solution of the prediction system. Both convective prediction and correction systems are shown to …
Global analysis of the high resolution infrared spectrum of methane 12CH4 in the region from 0 to 4800 cm-1
2009
International audience; We report the global analysis of methane (12CH4) lines from high resolution rovibrational spectra including accurate line positions and intensities in the region 0–4800 cm−1. This covers four polyads: The Ground State Monad (rotational levels), the Dyad (940–1850 cm−1, 2 vibrational levels, 2 sublevels), the Pentad (2150–3350 cm−1, 5 vibrational levels, 9 sublevels) and the Octad (3550–4800 cm−1, 8 vibrational levels, 24 sublevels) and some of the associated hot bands (Pentad−Dyad and Octad−Dyad). New Fourier transform infrared (FTIR) spectra of the Pentad and Octad regions have been recorded with a very high resolution (better than 0.001 cm−1 instrumental bandwidth,…
Research on the machining process modeling of a rotational mold using CAM applications
2021
Rotational molding is a unique process, with a high growth rate, which allows the use of geometries and materials adapted to particular needs. It is superior to other manufacturing methods in terms of low cost, break-even point and size of parts that can be manufactured. Rotational molding products are often a substitute, with a lower mass, for traditionally used materials. In this scientific paper it is analyzed the recent literature related to the field of rotational molding processes. It also addresses the issue of processing a rotational mold, with the main purpose of optimizing the cutting regime. In this context, it is highlighted the way of processing the surface of the outer mold ba…
Comparison of Postoperative Coronal Leg Alignment in Customized Individually Made and Conventional Total Knee Arthroplasty
2021
Neutral coronal leg alignment is known to be important for postoperative outcome in total knee arthroplasty (TKA). Customized individually made implants (CIM) instrumented with patient-specific cutting guides are an innovation aiming to increase the precision and reliability of implant positioning and reconstruction of leg alignment. We aimed to compare reconstruction of the hip–knee–ankle angle (HKA) of the novel CIM system iTotal™ CR G2 (ConforMIS Inc.) to a matched cohort of the off-the-shelf (OTS) knee replacement system Vanguard™ CR (Zimmer Biomet). Retrospective analysis of postoperative coronal full-leg weight-bearing radiographs of 562 TKA (283 CIM TKA, 279 OTS TKA) was conducted. V…
Alignment of linear molecules by short duration laser pulses
2005
Alignment of linear molecules is efficiently induced by strong linearly polarized laser pulses. In the case of short pulses with respect to molecular rotation, periodic alignment appears in field-free conditions after the extinction of the field. This manuscript presents three techniques where the value of allows to quantify alignment without molecular dissociation nor additional alignment. They use a weak time-delayed probe pulse which experiences the optical properties of an aligned sample and shows modification of its characteristics. The first of them measures a depolarization due to the birefringence of the sample. The second one is based on the defocusing produced by the spatial distr…