Film element

The resolution of potentiometric transducers is dependent upon the construction of the resistance element. In the case of a wire-wound resistance, in order to obtain a high resistance in a small space, the resistance wire is wound on to a mandrel or card which is straight or formed into a circle or helix depending upon the motion of the contact. This limits the resolution of the transducer as the wiper moves from one wire to the next on the mandrel. The best resolution that can be obtained is about 0.01 per cent (see Section 6.10.1). Typical wire-wound potentiometers have strokes of between 0.0025 m and 0.5 m and rotational versions from about 10° of arc to 50 turns. An alternative often employed is the conductive plastic film element. This provides a continuous resistance element and thus, a zero resolution, but such elements suffer from a higher temperature coefficient of resistance. A more recent development is a combination of earlier types in which a conductive plastic coating is sprayed on to a wire-wound resistor. 

Thin-Film Elemental Analyses for Precise Characterization of Minerals... 

With a known mineral, as determined by electron diffraction or other technique (such as X-ray diffraction), determination of the stoichiometry and structural formula can be a suitable test for analytical precision of thin-film elemental analyses. This simple test follows the practice commonly employed for electron microprobe data in which the accuracy (and completeness) of an analysis is judged by the departure from stoichiometry calculated for a given mineral. Thus, thin-film analyses of olivines, pyroxenes, garnets, feldspars and many other common rock-forming minerals can be examined for internal consistency via a calculation of structural formulae. 

Dynamic micromagnetics simulations show that shape, size, and damping constant significantly influence the switching behavior of thin film elements. The magnetization reversal of submicron NiFe elements was found to be a two stage process. At first, the magnetization rotates almost in plane towards... 

The metallic elements are all potentially very reactive towards air, water and most elements, but Be and Mg form passivating oxide films. Elemental magnesium is manufactured in large... 

This is becoming known by the above name but the name used in the seminal papers of Curme et al. and Spayd et al. of Eastman Kodak Company is multi layer film elements for clinical analysis 44-45). It is a technique which unites two aspects of clinical analysis. One is the procedure for carrying out quantitative tests on fibre strips. These strips may be dipped into a sample of urine and instantly reveal the concentration of up to 8 basic components it is an elegant variation of indicator paper. The other aspect is the increasing use being made of biological methods, particularly enzyme methods for clinical analysis. 

The average variation in thickness along the profile is determined from a series of photographs of the pattern of interference fringes. The variation is caused by film thinning due to gravity and thus the change in film thickness due to elastic strains of film elements is found. 

Curme, H.G., Columbus, R.L., Dappen, G.M. et al. (1978). Multilayer film elements for clinical analysis general concepts. Clin. Chem. 24, 1335-1342. 

Takai, T., Kohno, M., Sakamoto, Y., Iwamoto, Y. and Matsuda, F. (1984). Clinical application of Fuji Drichem-IOOO glucose analyzer using multilayer-film elements. Hormon to Rinsho 32, 477-481. 

Ten pi serum sample is applied to the thin-film element. After a 5 minutes incubation at 37 C, 10 pi of hydrogen peroxide solution is applied. The rate of formation of the dye, monitored at 670 nm by reflectance densitometry, is measured during a second 5 minutes incubation at 37 C. 

E245 Burdick, B.A. (1986). A dry-reagent thin-film element for urea nitrogen determination in whole blood. Clin. Chem. 32, 1195, Abstr. 724. 

E282 Ratge, D., Kohse, K.P., Knoll, E. and Wisser, H. (1986). Evaluation of the multilayer technique using thin-film elements for analysis of electrolytes, substrates and enzymes. Poster presented at Gemeinsame Jahrestagung der Deutschen, Schweizerischen, Osterreichischen und Franzosischen Gesellschaft fiir Klinische Chemie, Basel, 22-25 October. 

E401 Van Brunt, N., Day, B., Downs, D., Roth, J., Smith, T., Kissel, T.R., Daniel, D.S. and Toner, J. (1987). Performance of a new improved ionophore with better Na selectivity in a multilayered film element. Clin. Chem. 33, 1005, Abstr. 609. 

Cur me HG, Columbus RL, Dappen GM, Elder TW, Fellow WD, Figueras J et al. Multilayer film elements for clinical analysis General concepts. Chn Chem 1978 24 1335-42. 

Table I Behavior of backmetal film elements and resistance of various...

Film Element Any small homogeneous region of a thin film. The film element includes the interfaces. 

The following tables include superconductive properties of selected elements, compounds, and alloys. Individual tables are given for thin films, elements at high pressures, superconductors with high critical magnetic fields, and high critical temperature superconductors. 

Only viscosity and gravity forces are acting on a film element with the thickness dy. A force balance (Nusselt 1916) leads to the equation... 

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