Electrical homogeneous

Micro/nanostructures generated using these and related top-down approaches are geometrically and electrically homogeneous, with layouts that can be controlled over a wide range to realize not only ribbons and wires but also bars, platelets, membranes, and other structures. The main limitations of the top-down approach are as follows (1) The composition of the fabricated objects is limited to materials that are readily available in wafer or thin-film forms, (2) the etching processes can lead to some level of roughness on the surfaces of the structures, and (3) dimensions of less than 20 nm, for other than the thickness, are difficult to obtain reliably. 

A deeper insight into the lateral electrical homogeneity of the films, the limiting mechanisms of the Hall mobility, and the thermal activation energies of shallow and deep defect levels can be gained by temperature-dependent Hall and deep level transient spectroscopy (DLTS) measurements [57,59,60]. To give an example, the temperature dependence of the Hall mobility and... 

The electrical properties of the homogeneous alloys (Hall effect, conductivity, thermoelectric power) were studied at room temperature on electrically homogeneous samples prepared under identical conditions. The measurements showed that the alloys in systems 1 through 5 have n-type conduction while those in system 6 have p-type conduction. Extrinsic conduction and a high carrier density have been established for the alloys in all the systems. The electrical conductivity and mobility (Fig. 2) decrease monotonically with an increase in the content of A B component in the solution. The thermoelectric power and the effective mass of the electrons have low values and vary little with the composition. 

Electrically Homogeneous controlled type 2 As > 0 Homogeneous Perpendicular to substrate surface... 

In this Section the results of polarizability calculations for the 12 configurations of the C2H4-C2H4 complex are given (Table 4.1). The input parameters of the configurations for calculations are the same as described in Sect. 3.2.4. The value of applied electric homogeneous field used in the finite-field procedure was chosen to be 0.001 a.u. 

Gutfreund (1943) wrote It seemed that it might be possible to apply the method to the separation of protein mixtures. Thus, if the electrodialysis of a mixture were carried out in a buffer solution at the isoelectric point of one particular protein, under suitable conditions of current density and of time, the other proteins would move to one or other of the membranes and there concentrate in the lower layers, thus leaving the required protein in solution in the upper layers. This could then be removed from the cell by appropriate means. By repeating the process at different pH s it should then be possible, by successive treatments, to resolve the mixture into a series of electrically homogenous constituents. ... 

Sample preparation. Dust samples are usually small, Ifequently less than 200 mg. These must be sieved to remove unwanted debris and select the desired particle size. Sieving not only reduces the sample size but may also subject the small particles to separation by static electricity. Homogeneous subsampling can also be a problem. 

In contrast to a direct injection of dc or ac currents in the sample to be tested, the induction of eddy currents by an external excitation coil generates a locally limited current distribution. Since no electrical connection to the sample is required, eddy current NDE is easier to use from a practical point of view, however, the choice of the optimum measurement parameters, like e.g. the excitation frequency, is more critical. Furthermore, the calculation of the current flow in the sample from the measured field distribution tends to be more difficult than in case of a direct current injection. A homogenous field distribution produced by e.g. direct current injection or a sheet inducer [1] allows one to estimate more easily the defect geometry. However, for the detection of technically relevant cracks, these methods do not seem to be easily applicable and sensitive enough, especially in the case of deep lying and small cracks. 

Let us consider a domain U e R, representing the three-dimensional flaw imbedded in a homogeneous conductive media, with electric conductivity uo and permeability The flawed region D is assumed to be inhomogeneous, and characterized by the relative real conductivity ... 

Modelling plasma chemical systems is a complex task, because these system are far from thennodynamical equilibrium. A complete model includes the external electric circuit, the various physical volume and surface reactions, the space charges and the internal electric fields, the electron kinetics, the homogeneous chemical reactions in the plasma volume as well as the heterogeneous reactions at the walls or electrodes. These reactions are initiated primarily by the electrons. In most cases, plasma chemical reactors work with a flowing gas so that the flow conditions, laminar or turbulent, must be taken into account. As discussed before, the electron gas is not in thennodynamic equilibrium... 

Wien analyzer. A velocity filter with crossed homogeneous electric and magnetic fields for transmitting only ions of a fixed velocity. 

Homogeneous sonochemistry typically is not a very energy efficient process (although it can be mote efficient than photochemistry), whereas heterogeneous sonochemistry is several orders of magnitude better. Unlike photochemistry, whose energy inefficiency is inherent in the production of photons, ultrasound can be produced with neatly perfect efficiency from electric power. A primary limitation of sonochemistry remains the small fraction... 

Solidification. The heat of the electric arc melts a portion of the base metal and any added filler metal. The force of the arc produces localized flows within the weld pools, thus providing a stirring effect, which mixes the filler metal and that portion of the melted base metal into a fairly homogeneous weld metal. There is a very rapid transfer of heat away from the weld to the adjacent, low temperature base metal, and solidification begins nearly instantaneously as the welding heat source moves past a given location. 

Another important class of titanates that can be produced by hydrothermal synthesis processes are those in the lead zirconate—lead titanate (PZT) family. These piezoelectric materials are widely used in manufacture of ultrasonic transducers, sensors, and minia ture actuators. The electrical properties of these materials are derived from the formation of a homogeneous soHd solution of the oxide end members. The process consists of preparing a coprecipitated titanium—zirconium hydroxide gel. The gel reacts with lead oxide in water to form crystalline PZT particles having an average size of about 1 ]lni (Eig. 3b). A process has been developed at BatteUe (Columbus, Ohio) to the pilot-scale level (5-kg/h). 

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