brain death is defined as the permanent, irreversible and concurrent loss of all brain and brain stem functions. brain death diagnosis is based on clinical criteria and it is not routine to use paraclinical studies. in some countries, electroencephalogram (eeg) is performed in all patients for the determination of brain death while there is some skepticism in relying on eeg as a confirmatory te...

Impurity effective mass in superfluid 4He I.O.Vakarchuk, V.V.Babin Ivan Franko Lviv State University, Department for Theoretical Physics, 12 Drahomanov St., UA-290005 Lviv, Ukraine Received June 9, 1998 The system of bose liquid + impurity is considered. The energy spectrum, as well as effective mass of impurity is calculated. For the case of an 3He atom in superfluid 4He numerical calculations...

In this work, we have performed a systematic study of the electrical transport properties both the resistivity and the thermoelectric power on bundles of single-walled carbon nanotubes SWCNTs , double-walled carbon nanotubes DWCNTs , and peapods derived from the same batch of initial SWNTs during in situ doping with potassium donor . The charge transfer effects in K-doping are similar in SWNTs ...

Efficient upconversion of photoluminescence (PL) from donor bound excitons is revealed in bulk and nanorod ZnO. Based on excitation power dependent PL measurements performed with different energies of excitation photons, two-photon-absorption (TPA) and two-step TPA (TS-TPA) processes are concluded to be responsible for the upconversion. The TS-TPA process is found to occur via a defect/impurity...

Room-temperature ferromagnetism is observed in (110) oriented ZnO films made from targets containing 5 at. % of Sc, Ti, V, Fe, Co, or Ni, but not Cr, Mn, or Cu ions. There are large moments, 2.6 micro(B) and 0.5 micro(B)/dopant atom for Co- and Ti-containing oxides, respectively. There is also a moment of 0.3 micro(B)/Sc. Magnetization is very anisotropic, with variations of up to a factor of 3...

We investigated the electron transport properties of n-GaN under an Ohmic-metal. Hall measurement results were compared for (A) before Ti-based metal deposition, (B) after deposition but annealing, (C) Ohmic and (D) Ohmic-metal removal, where multi-probe-Hall device measurements are required (C), while others, (A), (B), (D), can be characterized by conventional measurements. The elucidated that...

A dynamic density-matrix renormalisation group approach to the spectral properties of quantum impurity problems is presented. The method is demonstrated on the spectral density of the flat-band symmetric single-impurity Anderson model. We show that this approach provides the impurity spectral density for all frequencies and coupling strengths. In particular, Hubbard satellites at high energy ca...

Trace impurity transport in tokamaks is studied using an electrostatic, collisionless fluid model for Ion-Temperature-Gradient (ITG) and Trapped-Electron (TE) mode driven turbulence in the presence of radio frequency (rf) fields in the ion cyclotron range of frequencies, and the results are compared with neoclassical predictions. Two separate effects of the rf field on ITG/TE-mode stability and...

Static and dynamic frictional phenomena at the interface with random impurities are investigated in a two-chain model with incommensurate structure. Static frictional force is caused by the impurity pinning and/or by the pinning due to the regular potential, which is responsible for the breaking of analyticity transition for impurity-free cases. It is confirmed that the static frictional force ...

We study a model of a d-wave superconductor with strong potential scatterers in the presence of antiferromagnetic correlations and apply it to experimental nuclear magnetic resonance NMR results on Zn impurities in the superconducting state of YBa2Cu3O7− . We then focus on the contribution of impurity-induced paramagnetic moments, with Hubbard correlations in the host system accounted for in Ha...