Regions Of High Mobility Research Articles

Contribution to the problem of the influence of the electric field on the conductivity of amorphous semiconductors

On the base of a polycrystalline model of amorphous material the possible mechanism of the influence of the electric field on the conductivity of amorphous semiconductors is explained. It is supposed that multiple tunnelling takes place through the barriers between the crystallites while in consequence of the work performed by the field the electron gets into the region of high mobility (i.e. into the energy region corresponding to high mobility).

Application des méthodes préparatives en veine liquide à la séparation des cellules sanguines

Human blood cells can be separated using an apparatus described by Hanning and co-workers (Model FF4 Desaga Heidelberg). The method of free flow preparative electrophoresis uses a specific property of blood cells when subjected to an electric field: their electrophoretic mobility. Three regions of migration can be defined: --a high mobility region (HMR); --a low mobility region (LMR) and --an intermediate mobility region (IMR). After the electrophoretic migration, the various cell fractions are identified. If human leucocytes are subjected to an electric field (40 volts/cm) it is possible to isolate several populations which differ by their membranes electric charge. The repartition of the neutrophiles granulocytes is twofold: --one fraction of high mobility (HMR) and --one fraction of low mobility (LMR). The meaning of these two populations is being discussed. Between these teo fractions is located the lymphocyte fraction which is represented by a single peak of intermediate mobility (IMR). Eosinophiles and monocytes are concentrated in low mobility fraction (LMR). With appropriate migration parameters (80 volts/cm, various component buffers) it is possible to obtain from lymphocytes, purified by density gradient, an electrophoretic separation of T and B lymphocytes population. Histograms obtained from quantitative measures (on collected cell fractions) show an unimodal distribution. When separated cells are characterized by three membranes markers (E. Rosettes, EAC Rosettes and surface immunoglobulins) the electrophoretic heterogeneity of B and T cells is then demonstrated. With E Rosettes (T cells) the majority of T lymphocytes is distributed in HMR and IMR. With EAC Rosettes and membrane immunofluorescence (B cells markers) the majority of B lymphocytes is found in the LMR. Thus an important enrichment of T and B sub-population is obtained, but contamination from one another still remains too important. More selective methods should lead to an improvement of this cell separation.

Conjecture on electron mobility in liquid hydrocarbons

We propose that the mobility of electrons in liquid hydrocarbons can be explained by a physical model which implies that the medium is microscopically inhomogeneous with regard to electron transport. Rotational fluctuations result in high and low mobility regions. The effective medium theory is utilized to correlate all the available mobility data with Vo the energy of the quasifree electron in each liquid.

Free-flow electrophoretic separation of lymphocytes. Two thoracic duct lymphocyte subpopulations studied after prolonged cannulation and immunization.

AbstractTwo different populations of small thoracic duct lymphocytes were separated by electrophoresis and characterized by electron microscopy. The high electrophoretic mobility region (HMR) consisted of small lymphocytes only and contained 75 % of the cells. After thoracic duct drainage or antigenic stimulation the morphological characteristics of the cells in the HMR remained unchanged. In contrast, the cells in the low electrophoretic mobility region (LMR) increased in quantity and showed morphological alterations after prolonged duct drainage or antigenic stimulation. Prior to stimulation small and medium lymphocytes were found in the LMR. After stimulation, blast‐like cells, immature plasma cells and “activated” lymphocytes, in addition to increased numbers of small lymphocytes, were detected.

Transverse Impact Ionization in Semiconductors

Abstract : The electron distribution function in the presence of crossed electric and magnetic fields is calculated, for a n-type semiconductor with isotropic electron scattering by acoustical and optical phonons. The results are applied to a semiconductor rod, subject to a longitudinally applied electric field and a transverse magnetic field. It is found, in agreement with measurements by M. Toda and M. Glicksman, that the ionization rate can increase with increasing magnetic field, due to the generated Hall electric field. The effect is closely related to a magnetic trapping of electrons in the low energy, high mobility region. (Author)

Palaeomagnetic study of tectonic rotation in the Carpathian mountains of Czechoslovakia

An extensive collection of palaeomagnetic samples of Upper Permian and Lowet Triassic rocks has been accumulated in the region of the Czechoslovakian western Carpathian Mountains. The original objective was to attempt an empirical correlation of rocks on the basis of normally and reversely magnetized zones, or to define rocks with reverse magnetization which could belong to the Permian if this period were to be characterized solely by reverse magnetization. This paper points out some hitherto unclarified global aspects and endeavours to solve such a problem; the boundary between the Permian and the Triassic has not yet been determined by using palaeomagnetism. On the other hand, abundant statistical palaeomagnetic material is available which data can be interpreted in relation to the rotational effect of Alpine tectonics. In these preliminary results systematic deviations of palaeomagnetic declination in samples from the Choč nappe could be discerned, and they are considered to be the result of Alpine tectonic movements of rotational character. This geophysical interpretation confirms the geological concept of overthrust structure for the western Carpathian region. In conclusion a brief mention is made about the fact that, even during global interpretation of palaeomagnetic pole positions, the possible effect of horizontal rotational movements of entire rock blocks should be taken into consideration. This is of special importance in regions of high tectonic mobility, and must be taken into account in explaining the differences in pole positions viewed from different continents (e.g., in connection with continental drift).