Temperature coefficients of electrical conductivity of electrolytes in methyl and ethyl alcohols

1936 ◽  
Vol 32 ◽  
pp. 1679 ◽  
Author(s):  
Alexander G. Ogston
Keyword(s):  
Electrical Conductivity ◽  
Temperature Coefficients

scholarly journals The electrical conductivity of thin films of mercury

1939 ◽  
Vol 172 (951) ◽  
pp. 530-539 ◽  
Keyword(s):  
Thin Films ◽  
Heat Treatment ◽  
Electrical Conductivity ◽  
Alkali Metals ◽  
High Vacuum ◽  
Experimental Measurements ◽  
Preliminary Note ◽  
Extended Study ◽  
Temperature Coefficients ◽  
Conductivity Of Thin Films

In the present paper an account is given of experimental measurements on the electrical conductivity of thin films of mercury prepared by evaporative deposition in a high vacuum according to the technique described in previous papers (Lovell 1936; Appleyard and Lovell 1937). In a brief preliminary note (Appleyard 1937) we have pointed out that the results for mercury are very different from those for the alkali metals, and that in particular a considerable thickness of mercury must be deposited on the pyrex surface before conductivity begins. We have since confirmed and extended these observations, obtained accurate absolute values for the thickness of the films, investigated their stability, and made an extended study of their temperature coefficients after heat treatment. A comparison with the results of previous workers is given later.

Synthetic metals based on graphite/aluminium halides

1971 ◽  
Vol 325 (1563) ◽  
pp. 437-445 ◽  
Keyword(s):  
Electrical Conductivity ◽  
Aromatic Compounds ◽  
Aluminium Chloride ◽  
Scattering Mechanism ◽  
Metallic Conductivity ◽  
Second Stage ◽  
Temperature Coefficients ◽  
Approximate Composition ◽  
Thermal Vibrations ◽  
Crystal Compound

Halides that are active Friedel Craft catalysts with aromatic compounds have been used to prepare synthetic metals. Aluminium bromide AlBr 3 intercalates readily into well oriented graphite between 70 and 80 °C. Second stage intercalation compounds are formed with approximate composition (C 33 AlBr 3.6 ). Aluminium chloride AlCl 3 does not intercalate spontaneously to any appreciable extent, unless free chlorine is also present. In this case, intercalation begins at about 60 °C and reaches a limit after several hours between 70 and 80 °C to produce a first stage intercalate with approximate composition (C 18 + AlCl 4 - .AlCl 3 ). In the direction of the a -axes both halide intercalates show good metallic conductivity with p characteristics. Unlike the parent graphite, temperature coefficients of resistivity of these synthetic metals are comparable with those of natural metals, indicating that thermal vibrations of charged atoms or molecules in the crystal compound contribute a dominant scattering mechanism controlling the electrical conductivity.

Electrical transport and band structure of GaAs

1979 ◽  
Vol 57 (2) ◽  
pp. 233-242 ◽  
Author(s):  
H. J. Lee ◽  
J. Basinski ◽  
L. Y. Juravel ◽  
J. C. Woolley
Keyword(s):  
Experimental Data ◽  
Electrical Conductivity ◽  
Band Structure ◽  
Hall Coefficient ◽  
Electrical Transport ◽  
Theoretical Calculations ◽  
Deformation Potential ◽  
Coupling Coefficients ◽  
Band Energy ◽  
Temperature Coefficients

Measurements of electrical conductivity σ and Hall coefficient RH have been made as a function of temperature in the range room to 500 °C on single crystal n-type tellurium doped samples of GaAs with carrier concentrations in the range 7.9 × 1021 to 4.7 × 1024/m3. Theoretical calculations of σ and RH have been made on a three band (Γ, L, X) model using the method of Fletcher and Butcher and the resulting values fitted to the experimental data by using the temperature coefficients of the band energy differences and various deformation potentials and band coupling coefficients as adjustable parameters. The results confirm the band ordering proposed by Aspnes but give slightly different temperature coefficient values. Values are given for the deformation potentials and band coupling coefficients and in particular the deformation potential of the Γ band is found to be 16.0 ± 0.5 eV.

Removing Substrate Background in TEM Microanalysis

1974 ◽  
Vol 32 ◽  
pp. 568-569
Author(s):  
John C. Russ ◽  
Nicholas C. Barbi
Keyword(s):  
Electrical Conductivity ◽  
Rapid Growth ◽  
Organic Film ◽  
Absolute Concentration ◽  
Background Signal ◽  
X Ray ◽  
Elemental Concentrations ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
The Continuum

The rapid growth of interest in attaching energy-dispersive x-ray analysis systems to transmission electron microscopes has centered largely on microanalysis of biological specimens. These are frequently either embedded in plastic or supported by an organic film, which is of great importance as regards stability under the beam since it provides thermal and electrical conductivity from the specimen to the grid.Unfortunately, the supporting medium also produces continuum x-radiation or Bremsstrahlung, which is added to the x-ray spectrum from the sample. It is not difficult to separate the characteristic peaks from the elements in the specimen from the total continuum background, but sometimes it is also necessary to separate the continuum due to the sample from that due to the support. For instance, it is possible to compute relative elemental concentrations in the sample, without standards, based on the relative net characteristic elemental intensities without regard to background; but to calculate absolute concentration, it is necessary to use the background signal itself as a measure of the total excited specimen mass.

Macromolecular structures of biological specimens are not obscured by controlled osmium impregnation

1983 ◽  
Vol 41 ◽  
pp. 606-607
Author(s):  
Klaus-Ruediger Peters ◽  
Samuel A. Green
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Critical Point ◽  
Metal Films ◽  
High Magnification ◽  
Osmium Impregnation ◽  
Instrumental Resolution ◽  
20 Nm ◽  
Continuous Metal

High magnification imaging of macromolecules on metal coated biological specimens is limited only by wet preparation procedures since recently obtained instrumental resolution allows visualization of topographic structures as smal l as 1-2 nm. Details of such dimensions may be visualized if continuous metal films with a thickness of 2 nm or less are applied. Such thin films give sufficient contrast in TEM as well as in SEM (SE-I image mode). The requisite increase in electrical conductivity for SEM of biological specimens is achieved through the use of ligand mediated wet osmiuum impregnation of the specimen before critical point (CP) drying. A commonly used ligand is thiocarbohvdrazide (TCH), first introduced to TEM for en block staining of lipids and glvcomacromolecules with osmium black. Now TCH is also used for SEM. However, after ligand mediated osinification nonspecific osmium black precipitates were often found obscuring surface details with large diffuse aggregates or with dense particular deposits, 2-20 nm in size. Thus, only low magnification work was considered possible after TCH appl ication.

Total Body Electrical Conductivity Measurements in the Neonate

1991 ◽  
Vol 18 (3) ◽  
pp. 611-627 ◽  
Author(s):  
Marta L. Fiorotto ◽  
William J. Klish
Keyword(s):  
Electrical Conductivity ◽  
Conductivity Measurements ◽  
Total Body
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