Electron thermalization distance distributions and thermal electron mobilities in dense liquid isobutane

1992 ◽  
Vol 70 (2) ◽  
pp. 327-332
Author(s):  
Takehisa Yoshinari ◽  
Norman Gee ◽  
Gordon R. Freeman
Keyword(s):  
Electron Scattering ◽  
Three Dimensional ◽  
Thermal Electron ◽  
Density Region ◽  
One Dimensional ◽  
Distance Distributions ◽  
Free Ion ◽  
Ion Yields ◽  
Arrhenius Temperature ◽  
Dense Liquid

Free ion yields [Formula: see text], were measured at electric field strengths E up to 6.7 MV m−1 in liquid isobutane at 556 ≤ d/kg m−3 ≤ 739 (294.4–114.6 K). The yields decreased with decreasing temperature and increasing density up to 677 kg m−3; further increases in density led to little change in [Formula: see text]. The thermalization distance distribution F(y) was estimated by fitting the field dependence of [Formula: see text] using the extended On sager model. At lower densities F(y) = YGP (three-dimensional Gaussian body with power tail) provided an adequate fit to the results, while at higher densities F(y) = YE (one-dimensional exponential distribution) was better. Thus the electron-scattering properties of liquid isobutane change somewhat with density. The thermalizing ability of liquid isobutane increased with increasing density up to ~660 kg m−3, then decreased at densities > 690 kg m−3. By comparison, the Arrhenius temperature coefficient of mobility of thermal electrons changed in the same density region: Eμ ≈ 7 kJ mol−1 at d < 660 kg m−3, and ≈ 16 kJ mol−1 at d > 690 kg m−3. Keywords: isobutane, electron thermalization distance, free ion yield, liquid, electron mobility, radiolysis.

Epithermal Electron Ranges and Thermal Electron Mobilities in Liquid Aromatic Hydrocarbons

1974 ◽  
Vol 52 (20) ◽  
pp. 3495-3506 ◽  
Author(s):  
Kyoji Shinsaka ◽  
Gordon R. Freeman
Keyword(s):  
Aromatic Hydrocarbons ◽  
Secondary Electron ◽  
Shielding Effect ◽  
Methyl Groups ◽  
Thermal Electron ◽  
Molecular Asymmetry ◽  
Trimethyl Benzene ◽  
Free Ion ◽  
Benzene Toluene ◽  
Ion Yields

Radiolysis free ion yields were measured as functions of electric field strength and temperature in benzene, toluene, 1,2-, 1,3-, and 1,4-dimethylbenzene, 1,2,3-, 1,2,4-, and 1,3,5-trimethylbenzene, 1,2,3,4- and 1,2,4,5-tetramethylbenzene, pentamethylbenzene, hexamethylbenzene, naphthalene, and anthracene. Secondary electron ranges bGP were estimated from the yields. The density-normalized ranges bGPd were almost constant, 34−38 × 10−8 g/cm2, from benzene up to the tetramethylbenzenes, then increased to 47 × 10−8 in pentamethyl- and 52 × 10−8 in hexamethylbenzene. In naphthalene and anthracene the normalized ranges were 32 and ∼20 × 10−8 g/cm2, respectively. Electron mobilities in the liquids at 293 K, and their activation energies, expressed in (cm2/V s, kcal/mol) were: benzene (0.114, 7.4); toluene (0.063, 3.4); 1,2-dimethylbenzene (0.018, 4.4); 1,3-dimethylbenzene (0.057, 4.5); 1,4-dimethylbenzene (0.062, —); 1,2,3-trimethylbenzene (0.022, 4.8); 1,2,4-trimethylbenzene (0.035, 4.3); 1,3,5-trimethyl-benzene (0.17, 3.2); 1,2,3,4-tetramethylbenzene (∼0.02, 5). The mobilities reflect migration retarding influences of the aromatic ring and molecular asymmetry, and a slight ring-shielding effect of methyl groups that tends to enhance the mobility.

Diffraction of Electrons by Two and Three Mutually Orthogonal Standing Light Waves

1975 ◽  
Vol 53 (2) ◽  
pp. 157-164 ◽  
Author(s):  
F. Ehlotzky
Keyword(s):  
Electron Scattering ◽  
Light Wave ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Dimensional Problem ◽  
One Dimensional ◽  
Standing Light Wave ◽  
Light Waves ◽  
The One ◽  
Rectangular Lattices

The one-dimensional problem of electron scattering by a standing light wave, known as the Kapitza–Dirac effect, is shown to be easily extendable to two and three dimensions, thus showing all characteristics of diffraction of electrons by simple two- and three-dimensional rectangular lattices.

Electron thermalization distances and free-ion yields in dense gaseous and liquid benzene

1992 ◽  
Vol 70 (6) ◽  
pp. 1618-1622 ◽  
Author(s):  
Norman Gee ◽  
Gordon R. Freeman
Keyword(s):  
Three Dimensional ◽  
Dielectric Constants ◽  
Zero Field ◽  
Fluid Density ◽  
Model Assumption ◽  
Liquid Benzene ◽  
Free Ion ◽  
Ion Yields ◽  
Yield Formula ◽  
Reduced Density

Electron thermalization has been studied in gaseous and liquid benzene at 4.1 ≤ d/kg m−3 ≤ 878 (temperatures 295–560 K) using measurements of the free-ion yield [Formula: see text] as a function of electric field strength E and temperature T. The measured [Formula: see text] values at each T were compared to those calculated using an extended Onsager model. Assumption of a three-dimensional Gaussian distribution of secondary electron thermalization distances YG resulted in too large a field dependence. The Gaussian with the small added tail, YGP, gave the correct dependence. Values of the yield extrapolated to zero field, [Formula: see text] and of the most probable thermalization distance bGP were obtained. Variation of the density-normalized distance bGPd with reduced density d/dc (dc = critical fluid density) was expected to be similar to that in ethene, due to the π-electrons in the two compounds. Instead, it was similar to that in ethane. Throughout the liquid range, epithermal electrons were de-energized less efficiently than in the gas at d < 0.5 dc where the benzene molecules are further apart. As the density increases above 2 dc the values of bGPd decreased as in other hydrocarbons, rather than like those in hexafluorobenzene, which increased sharply. Dielectric constants were also measured up to 560 K.

Temperature dependence of the resistivity of Hg3–δAsF6

1982 ◽  
Vol 60 (9) ◽  
pp. 1348-1357 ◽  
Author(s):  
E. Batalla ◽  
W. R. Datars
Keyword(s):  
Fermi Surface ◽  
Temperature Dependence ◽  
Electron Scattering ◽  
Short Range ◽  
Linear Chain ◽  
Three Dimensional ◽  
One Dimensional ◽  
Anisotropic Superconductor ◽  
Short Range Ordering ◽  
Long Range Ordering

The resistivity of the linear-chain mercury compound Hg3–δAsF6 is reported in the temperature range 1.4–300 K. Electron scattering by one-dimensional and three-dimensional phonons on a cylindrical Fermi surface is used to calculate the temperature dependence of the resistivity which agrees with measurements of the resistivity between 4.2 and 90 K. The resistivity is determined by the Montgomery method which is extended to the case when electrical probes are not at the corners of a sample. The anisotropy ρc/ρa of the resistivity is in the range 95 ± 10 between 40 and 180 K. It is explained by a 1.4% undulation along the Fermi surface cylinders. Changes in the anisotropy give evidence of three-dimensional, long-range ordering at 120 K and short-range ordering of the mercury chains between 180 and 200 K reported previously. Hysteresis in the resistivity shows an unusual transition at 217 ± 3 K which is evident only upon cooling samples. There is no evidence of zero, c-axis resistivity below 4.1 K to support the suggestion that Hg3–δAsF6 is an anisotropic superconductor.

Electron thermalization-distance distributions in electron-attaching fluids

1990 ◽  
Vol 68 (9) ◽  
pp. 930-934 ◽  
Author(s):  
Norman Gee ◽  
Gordon R. Freeman
Keyword(s):  
Carbon Monoxide ◽  
Field Strength ◽  
Electric Field ◽  
Carbon Disulfide ◽  
Sharp Decrease ◽  
Liquid Carbon ◽  
Distance Distributions ◽  
Free Ion ◽  
Ion Yields ◽  
Liquid Carbon Disulfide

The electron ejected from a molecule by an energetic impact moves away from the resultant ion and loses energy to the molecules with which it collides. The distance such electrons travel away from their ions during thermalization can be estimated by measuring the free-ion yields as a function of electric-field strength. This was done in gaseous and liquid carbon disulfide and hexafluorobenzene over wide ranges of densities. The electron thermalization-distance distribution in C6F6 was the same as that in most other liquids; it was a Gaussian distribution with a power tail. However in liquid CS2 the distribution was different, an exponential with a power tail, as in liquid nitrogen and liquid carbon monoxide. The different distributions reflect differences in the thermalization processes. The thermalizing ability of both CS2 and C6F6 is less in the liquid than in the gas. There is an especially sharp decrease in the thermalizing ability of CS2 at the highest densities.

Structure and function of neural networks in the retina

1988 ◽  
Vol 46 ◽  
pp. 26-27
Author(s):  
Peter Sterling
Keyword(s):  
Ganglion Cells ◽  
Three Dimensional ◽  
Structure And Function ◽  
Synaptic Connections ◽  
Visual Axis ◽  
One Dimensional ◽  
Cat Retina ◽  
Ultrathin Sections ◽  
And Function ◽  
Insight Into

The synaptic connections in cat retina that link photoreceptors to ganglion cells have been analyzed quantitatively. Our approach has been to prepare serial, ultrathin sections and photograph en montage at low magnification (˜2000X) in the electron microscope. Six series, 100-300 sections long, have been prepared over the last decade. They derive from different cats but always from the same region of retina, about one degree from the center of the visual axis. The material has been analyzed by reconstructing adjacent neurons in each array and then identifying systematically the synaptic connections between arrays. Most reconstructions were done manually by tracing the outlines of processes in successive sections onto acetate sheets aligned on a cartoonist's jig. The tracings were then digitized, stacked by computer, and printed with the hidden lines removed. The results have provided rather than the usual one-dimensional account of pathways, a three-dimensional account of circuits. From this has emerged insight into the functional architecture.

Exploring the Multidimensional Facets of Authoritarianism: Authoritarian Aggression and Social Dominance Orientation

2008 ◽  
Vol 67 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Stefano Passini
Keyword(s):  
Social Dominance ◽  
Factor Model ◽  
Three Dimensional ◽  
Social Dominance Orientation ◽  
Model Fit ◽  
Regression Analyses ◽  
One Dimensional ◽  
Confirmatory Factor ◽  
The One ◽  
Better Than

The relation between authoritarianism and social dominance orientation was analyzed, with authoritarianism measured using a three-dimensional scale. The implicit multidimensional structure (authoritarian submission, conventionalism, authoritarian aggression) of Altemeyer’s (1981, 1988) conceptualization of authoritarianism is inconsistent with its one-dimensional methodological operationalization. The dimensionality of authoritarianism was investigated using confirmatory factor analysis in a sample of 713 university students. As hypothesized, the three-factor model fit the data significantly better than the one-factor model. Regression analyses revealed that only authoritarian aggression was related to social dominance orientation. That is, only intolerance of deviance was related to high social dominance, whereas submissiveness was not.

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