Density effective mass

At temperatures above 1100 °C (p S 1.3 g cm ), the measured conductivity is clearly less than the NFE values. The gradual failure of the Ziman theory at high temperatures and low density is probably not due to the breakdown of NFE conditions at 1.3 g cm . As stated above, the evidence suggests that the NFE approximation is valid at least down to a density of about 1.1 g cm . Estimates of A from the conductivity (Winter et al., 1987) indicate that the condition A a is only reached in the density range p 0.8 g cm . The NFE breakdown is more likely to reflect the increased importance of electron correlations at low density (Sec. 3.2). Simple arguments (Mott, 1974) based on the ideas of Brinkman and Rice suggest that the Ziman conductivity should be reduced by a factor (m ) in the range where the effective mass (density of states) is enhanced by correlations. 

In this connection we think that the rather good agreement between the experimental and theoretical values obtained for the effective mass, density of states, and charge distribution by our double-C ab initio calculation may encourage the use of this method for the further investi-... 

II.2 Singular behavior of effective mass density of capillary waves... 

The total effective mass density per unit interfacial area, m, is given by ... 

The supporting medium was water at 298 K (p = 0.99727), and the density of latex is 1.2049 g cm . The latex particles had an average radius of 2.12 x 10 mm hence, their effective mass corrected for buoyancy is their volume times the density difference Ap between latex and the supporting medium, water... 

Below about 0.5 K, the interactions between He and He in the superfluid Hquid phase becomes very small, and in many ways the He component behaves as a mechanical vacuum to the diffusional motion of He atoms. If He is added to the normal phase or removed from the superfluid phase, equiHbrium is restored by the transfer of He from a concentrated phase to a dilute phase. The effective He density is thereby decreased producing a heat-absorbing expansion analogous to the evaporation of He. The He density in the superfluid phase, and hence its mass-transfer rate, is much greater than that in He vapor at these low temperatures. Thus, the pseudoevaporative cooling effect can be sustained at practical rates down to very low temperatures in heHum-dilution refrigerators (72). 

Remarkably, although band stmcture is a quantum mechanical property, once electrons and holes are introduced, theit behavior generally can be described classically even for deep submicrometer geometries. Some allowance for band stmcture may have to be made by choosing different values of effective mass for different appHcations. For example, different effective masses are used in the density of states and conductivity (26). 

General Principles There are two main types of mass flowmeters (1) the so-called true mass flowmeter, which responds directly to mass flow rate, and (2) the inferential mass flowmeter, which commonly measures volume flow rate aud flmd density separately. A variety of types of true mass flowmeters have been developed, including the following (a) the Maguus-effect mass flowmeter, (b) the axial-flow, transverse-momentum mass flowmeter, (c) the radial-flow, transverse-momentum mass flowmeter, (d) the gyroscopic transverse-momentum mass flowmeter, aud (e) the thermal mass flowmeter. Type b is the basis for several commercial mass flowmeters, one version of which is briefly described here. 

The measured magnetic susceptibility of multilayer buckytubes for xb S approximately half xg of graphite. This can be interpreted as follows. We recall that crystalline graphite is a semimetal with a small band overlap and a low density of carriers (10 /cm )[33, 34] the in-plane effective mass is small (rn ... 

Figure 1. Attrition modes and their effects on the particle size distribution (q3 = mass density distribution).

In high-mobility liquids, the quasi-free electron is often visualized as having an effective mass m different fron the usual electron mass m. It arises due to multiple scattering of the electron while the mean free path remains long. The ratio of mean acceleration to an external force can be defined as the inverse effective mass. Often, the effective mass is equated to the electron mass m when its value is unknown and difficult to determine. In LRGs values of mVm 0.3 to 0.5 have been estimated (Asaf and Steinberger,1974). Ascarelli (1986) uses mVm = 0.27 in LXe and a density-dependent value in LAr. 

Equation (1) suggests that tunnel junctions should be ohmic. This is true only for very small bias. A much better description of the tunneling current results when the effects of barrier shape, changes in barrier with applied potential, and effective mass of the electron are all included. An example of such an improved relationship is given by (2), where / is the current density, a is a unitless parameter used to account empirically for non-rectangular barrier shape and deviations in the effective electron mass, and barrier height given by B = (L + work function of the left-hand metal ... 

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