Frequency, carrier natural

In pulse version of MIA method the probes excite in tested object (TO) free attenuating pulses. Their carrier frequencies coincide with natural frequencies of transmitting probe vibrator loaded to the mechanical impedance Zg = / (Z -tZ,), where Z is elastic... 

The most interesting aspect of the results of the study by Lee etal (2004) is that they also differ from those in a Caucasian population (Smeraldi, Benedetti Zanardi, 2002). The authors reported a more favorable natural history in those with the s/s genotype than in 1-allele carriers, which also differs from acute antidepressant responses in Caucasian populations. The frequencies of the s and 1 alleles among the Korean sample were approximately 86% and 14%, respectively, while the corresponding figures for Caucasians are 43% and 57% (Lesch etal, 1996). 

The phase coherence can also be achieved simply by using a linearly phase incremented pulse (PIP) without resorting to additional hardware. Since all the RF pulses utilized for constructing a PIP have the same carrier, no frequency jump is involved. Consequently, phase coherence between the RF pulses applied before and after the PIP is reserved naturally. 

Depending on the appearance of the spectrum when the angular frequency cu approaches zero, dielectric responses of materials are often classified as being either dipolar in nature or carrier dominated. In the first case, the polarization is attributed to the reorientation of permanent dipoles, and in the latter to the displacement of partially mobile charge carriers. These two behaviors may be interpreted as being manifestations of different values of the exponent a in a power law of the form oc at low frequencies when cu approaches zero, tends to zero whenever the exponent a > 1 but increases indefinitely when a < 1. Likewise, the real part / approaches a finite value when a > 1 but increases indefinitely in the same way as the imaginary part when a < 1. Since no finite value is approached when a < 1, this case usually is referred to as low-frequency dispersion (104,105). 

Fundamental differences in mechanism of conduction are responsible for this. A carrier which has just carried an ion across the membrane must go back or reset before it can carry another ion in the same direction. A fixed channel on the other hand, if it is open, is equally available to carry ions from both sides of the membrane. Thus, for a carrier, large, long-lasting fluctuations (low-frequency noise) are damped out because of the nature of the carrier mechanism, which must reset. 

The experimental results obtained by the nuclear magnetic resonance (NMR) method can be used to determine the nature of the chemical bonding and, particularly, the susceptibility and the carrier density. Nuclear magnetic resonance can be used to deduce information on the structure of a substance from the resonance line width and profile, from the spin-lattice relaxation, and from the shift of the resonance frequency. We shall consider some results obtained from the shift of the NMR line. 

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