in the present study, the q factor is obtained for the central alborz in iran using the lg coda method. the energy of a seismic wave decays while passing through a ‘real’ medium such as the earth which is not completely elastic. the decay in energy is due to non-elastic phenomena and is called intrinsic attenuation and is characterized with the q parameter, the large values of which represent s...

Using long-term data on rainfall and annual runoff, an investigation was made of the spatial and temporal variability of rainfall and runoff in the Casamance River basin located in southern Senegal, West Africa. A 5-year moving average was employed to identify trends in the data. Monthly and annual rainfall tends to have been decreasing, and the annual maximum temperature rising from around the...

Gradient information is used in volume rendering to classify and color samples along a ray. In this paper we present an analysis of the theoretically ideal gradient estimator and compare it to some commonly used gradient estimators. A new method is presented to calculate the gradient at arbitrary sample positions, using the derivative of the interpolation lter as the basis for the new gradient ...

In volume rendering gradient information is used to classify and color samples along a ray. In this paper we present an analysis of the theoretically ideal gradient estimator and compare some commonly used gradient estimators with the ideal estimator. A new method is presented to calculate the gradient on an arbitrary position, using the derivative of the interpolation lter as the basis for the...

The design process and the magnetic measurements 011 a permanent magnet asymmetric dipole to be used for magnetic selection in a Cs beam frequency standard is presented Tbe design target is to create a magnetic induction gradient of 50 Tlm in a zone extending 10 mm in width and 50 mm in length. The computer aided design process is outlined and design predictions are compared with measurements o...

In pulsed-gradient spin-echo NMR, one measures the disof rotational dipolar auto-correlation spectral density via the ‘‘probe’’ of the spin relaxation times, where T1 samples at placement of nuclear spins over the time interval, D, between two gradient pulses, of duration d and amplitude g , positions v0 and 2v0 , while T1r samples at v1 and 2v1 . The purpose of the present Communication is to ...

Oscillatory instability at the Hopf bifurcation is a dynamical phenomenon that has been suggested to characterize active non-linear processes observed in the auditory system. Networks of oscillators poised near Hopf bifurcation points and tuned to tonotopically distributed frequencies have been used as models of auditory processing at various levels, but systematic investigation of the dynamica...

Restrictions to diffusion result in the dispersion of the bulk diffusion coefficient. We derive the exact universal high-frequency behavior of the diffusion coefficient in terms of the surface-to-volume ratio of the restrictions. This frequency dependence can be applied to quantify structure of complex samples with NMR using oscillating field gradients and static-gradient CPMG. We also demonstr...

We predict that two-dimensional electrons confined by a magnetic field gradient resonantly transfer energy to the electromagnetic field by a process of inverse electron spin resonance that is realized when the frequency of an open orbit equals the Larmor frequency. The calculated emission spectra show multiple peaks modulated by strong optical nonlinearities whose frequencies may be tuned by th...