Über den Einfluß der elastischen Spannungen auf den Verlauf der Magnetisierungskurve

Zeitschrift für Physik A Hadrons and nuclei - Der Verlauf der Magnetisierungskurve der elastisch gespannten Ferromagnetika wird für kleinere Magnetisierungen theoretisch und experimentell...     

Atomic effects in tritium beta decay and their role in determining the ratio GA/GV and the lifetime of the free neutron

The helium-isotope mass-spectroscopy method for measuring the triton decay constant for various cases of the electron environment was used to determine the tritium half-life without allowance for decay to beta-electron bound states and to calculate the respective reduced half-life, which proved to be (fT _1/2) _t = 1129.6 ± 30.0 s. The equations relating fT _1/2 to G _A /G _V made it possible to obtain the value of (G _A /G _V ) _t = −1.2646 ± 0.0035 and to estimate the neutron lifetime at τ _n = 890.3 ± 3.9(stat.) ± 1.4(syst.) s. __________ Translated from Yadernaya Fizika, Vol. 67, No. 3, 2004, pp. 484–489. Original Russian Text Copyright ? 2004 by Akulov, Mamyrin.     

Uniqueness of solutions of mixed problems and a Cauchy problem for parabolic equations of high order with unbounded coefficients

New uniqueness classes of generalized solutions (generalized Tacklind classes) of initial-boundary-value problems are found for linear and quasilinear divergent parabolic equations of high order with coefficients increasing at infinity.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 44, No. 2, pp. 149–155, February, 1992.     

Measurement of viscous flow velocity and flow visualization using two magnetic resonance imagers

The accuracies of measuring the velocity field using clinical and research magnetic resonance imagers are compared. The flow velocity of a fluid simulating blood in a carotid artery model connected to a programmable pump was measured. Using phase-contrast magnetic resonance tomography, the velocity distributions in the carotid artery model were obtained and compared with the analytical solution for viscous liquid flow in a cylindrical tube (Poiseuille flow). It is found that the accuracy of the velocity measurement does not depend on the field induction and spatial resolution of the imagers.     

Frequency doubling of Yb-doped fiber laser to 515 nm

Operation of Yb-doped fiber laser (YDFL) at short wavelengths (about 1030 nm) is known to be possible with relatively short active fibers. Frequency doubling of such a laser is studied. It is shown that, in contrast to conventional YDFLs, operating around 1080 nm, the short-wavelength YDFL does not exhibit significant spectral broadening induced by nonlinear effects. Thus, the generated spectrum remains narrower than the FBG reflection profile, which allows an almost twofold intracavity intensity enhancement. Consequently, the second harmonic generation in the KTP crystal placed inside the YDFL cavity appears more effective than the generation in the single-pass scheme by an order of magnitude. An output power of about 0.4 W at a wavelength of 515 nm is demonstrated.