Search results for "Absolute value"
showing 10 items of 33 documents
Systematic and statistical uncertainties of the hilbert-transform based high-precision FID frequency extraction method.
2021
Abstract Pulsed nuclear magnetic resonance (NMR) is widely used in high-precision magnetic field measurements. The absolute value of the magnetic field is determined from the precession frequency of nuclear magnetic moments. The Hilbert transform is one of the methods that have been used to extract the phase function from the observed free induction decay (FID) signal and then its frequency. In this paper, a detailed implementation of a Hilbert-transform based FID frequency extraction method is described, and it is briefly compared with other commonly used frequency extraction methods. How artifacts and noise level in the FID signal affect the extracted phase function are derived analytical…
An ab initio potential energy surface for the C2H2-N2 system
2012
International audience; An ab initio potential energy surface determined at the CCSD(T) level of theory is presented for the van der Waals complex C2H2-N2. Additional calculations performed with the HF- and DFT-SAPT methods compare well with the CCSD(T) results and allow a better understanding of the main features of this interaction potential surface. An expansion of this surface over spherical harmonics has also been performed. The global energy minimum of the complex is obtained for the linear conformation. The T conformations are the least attractive. Such characteristics mainly arise because of the variation, in sign and in absolute value of the electrostatic energy between all these c…
A modified applicative criterion of the physical model concept for evaluating plot soil erosion predictions
2015
Abstract In this paper, the physical model concept by Nearing (1998. Catena 32: 15–22) was assessed. Soil loss data collected on plots of different widths (2–8 m), lengths (11–44 m) and steepnesses (14.9–26.0%), equipped in south and central Italy, were used. Differences in width between plots of given length and steepness determined a lower data correlation and more deviation of the fitted regression line from the identity one. A coefficient of determination between measured, M , and predicted, P , soil losses of 0.77 was representative of the best-case prediction scenario, according to Nearing (1998). The relative differences, Rdiff = ( P − M ) / ( P + M ), decreased in absolute value a…
Anomalous pressure dependence of the Lamb-Mössbauerf-factor in the spin crossover system [Fe(2-pic-ND2)3]Cl2·EtOD
1987
The pressure dependence of the Lamb-Mossbauer factor of the spin crossover compound [Fe(2-pic-ND2)3]Cl2·EtOD(2-pic-ND2=2-picolylamine, deuterated at the−NH2 group) has been measured at pressures up to 1500 bar and at three temperatures (115.7, 146.7, 185.6 K) around the transition temperatureT t=135 K. The temperature dependence of the unit cell volume has been determined by X-ray diffraction. In the transition region (T=146.7 K), the pressure dependence of thef-factor shows an anomalous increase as compared to the dependence below and above the transition. The behaviour off(p, T), its anomaly and absolute value, can be consistently explained within a theoretical model which treats the comp…
The maximal coefficient of ternary cyclotomic polynomials with one free prime
2014
A cyclotomic polynomial Φn(x) is said to be ternary if n = pqr, with p, q and r distinct odd primes. Let M(p, q) be the maximum (in absolute value) coefficient appearing in the polynomial family Φpqr(x) with p < q < r, p and q fixed. Here a stronger version of the main conjecture of Gallot, Moree and Wilms regarding M(p, q) is established. Furthermore it is shown that there is an algorithm to compute M(p): = max {M(p, q): q > p}. Our methods are the most geometric used so far in the study of ternary cyclotomic polynomials.
Influence of impurity scattering on Drude response in heavy-fermion UPd2Al3
2010
The frequency-dependent conductivity of heavy-fermion metals can often be described within the picture of the Drude response: the transport relaxation rate is the only relevant frequency scale and, furthermore, reduced by orders of magnitude compared to normal metals. While the relaxation-time enhancement corresponds to the effective-mass enhancement in these materials, i.e. a fundamental material characteristic, the absolute value of the relaxation time depends on the details of the relevant scattering processes. Here we discuss the influence of impurity scattering on the Drude response of the heavy fermions in UPd2Al3 by comparing different thin film samples.
Skyrmion-number dependence of spin-transfer torque on magnetic bubbles
2015
We theoretically study the skyrmion-number dependence of spin-transfer torque acting on magnetic bubbles. The skymrion number of magnetic bubbles can take any integer value depending on the magnetic profile on its circumference and the size of the bubble. We find that the transverse motion of a bubble with respect to the charge current is greatly suppressed as the absolute value of the skyrmion number departs from unity, whereas the longitudinal motion is less sensitive.
NOAA-AVHRR Orbital Drift Correction: Validating Methods Using MSG-SEVIRI Data as a Benchmark Dataset
2021
National Oceanic and Atmospheric Administration–Advanced Very High Resolution Radiometer (NOAA-AVHRR) data provides the possibility to build the longest Land Surface Temperature (LST) dataset to date, starting in 1981 up to the present. However, due to the orbital drift of the NOAA platforms, no LST dataset is available before 2000 and the arrival of newer platforms. Although numerous methods have been developed to correct this orbital drift effect on the LST, a lack of validation has prevented their application. This is the gap we bridge here by using the 15 min temporal resolution of Meteosat Second Generation–Spinning Enhanced Visible and Infra-Red Imager (MSG-SEVIRI) data to simulate dr…
Thermal nucleation of cavities in liquid helium at negative pressures
1993
We have investigated the nucleation rate at which cavities are formed in $^{4}\mathrm{He}$ and $^{3}\mathrm{He}$ at negative pressures due to thermal fluctuations. To this end, we have used a density functional that reproduces the He liquid-gas interface along the coexistence line. The inclusion of thermal effects in the calculation of the barrier against nucleation results in a sizable decrease of the absolute value of the tensile strength above 1.5 K.
Extra tension at electrode-nanowire adhesive contacts in nano-electromechanical devices
2017
Abstract We report a strong tangential component of the reaction force at electrode to nanowire adhesive contact which was previously established using electrostatic attraction. The reaction force tangential component absolute value was found to be comparable to or even bigger than the corresponding normal component. This effect is important for understanding of the mechanics of nano-electromechanical devices. Both the experiment and the corresponding theory are presented. Fitting of the obtained analytical solutions to experimental data was used to measure the reaction force acting at the contact for several nanowire-electrode configurations.