Centrifugal deposition method

Low-loss, high-bandwidth graded-index plastic optical fiber fabricated by the centrifugal deposition method. Appl. 

Cytology, that is, the visual inspection of exfoliated cells, is most commonly carried out for smears of cells, which are deposited ( smeared ) directly from brushes, spatulas or other exfoliation devices onto microscope slides. Such smears are unsuitable for spectral analysis, since they contain clumps of cells, cellular debris, erythrocytes and other contamination. However, better methods of cell slide preparations have been introduced into cytology, among them the ThinPrep methods developed by Cytyc, Inc. (see ref. 7), and spin centrifugation deposition techniques. These methods are very good for real exfoliated cell samples,7 since they permit the purification of the cell exfoliate, enrichment in the cells desired for analysis and produce good monolayers for visual cell inspection. 

In this building-block approach, the components are synthesized separately and then hybridized via linking agents/methods that utilize covalent, noncovalent (van der Waals, n-n interactions, hydrogen bonding), or electrostatic interactions. The attachment of these building blocks often requires the chemical modification of at least one component to overcome the differences in surface chemistry. As a consequence deposition is often limited to the first layer. Excess nanoparticles can be removed by filtration or centrifugation. 

Self-supporting inorganic membranes can be formed with or without a substrate. In either case the precursor sol, consisting of either a colloidal suspension or a polymeric solution, must be formed. To produce a membrane supported on a substrate (i.e. a supported membrane), a preformed porous support is dipped in the precursor sol and a gel forms at the surface of the support typically by the slipcasting method [48]. Another approach is spin coating, in which an excess amount of liquid is deposited onto a substrate and then thinned uniformly by centrifugal force [12]. To produce a non-supported membrane, the liquid is simply poured into a mold of appropriate shape and allowed to dry. All these processes need to be done before the gel point which is accompanied by a large increase in viscosity. 

Ammonium nitrate, NH4NOa.—The nitrate can be prepared by the general methods applicable to the ammonium salts. It is also produced by heating the nitrate of an alkali-metal with ammonium sulphate at 160° to 200° C., the fused ammonium nitrate being separated from the solid alkali-metal sulphate by centrifuging.11 Another method consists in cooling a concentrated solution of sodium nitrate and ammonium sulphate to —15° C., sodium sulphate being precipitated. On evaporation of the mother-liquor, most of the sodium sulphate is deposited addition of nitric acid to the clear solution causes crystallization of the ammonium nitrate.12 When sodium nitrate is... 

Method. Prepare seven 10-ml centrifuge tubes each containing 2 ml of a 10% solution of trichloroacetic acid. To five of the tubes add 1 ml each of the five standard solutions, and to the other two tubes add 1 ml of normal plasma and 1 ml of the plasma sample respectively. Agitate each tube for a few seconds, and then centrifuge at 3000 rpm for 5 minutes to deposit the protein precipitate. 

Three distinct methods are therefore available for calculating the mass distribution of particles in suspension for a series of sector-shaped tubes filled to a series of levels. First, the mass fraction of particles larger than a known diameter may be calculated from equation (8.77) and the distribution function determined from the slope of the cumulative mass deposited against S. Secondly, the distribution function may be calculated directly in terms of the first and second derivatives of the fraction sedimented with respect to the length of the column of suspension centrifuged by use of equation (8.77). Thirdly, from the sedimentation -time curve at a series of levels, the distribution functions may be calculated by the use of equation (8.77). 

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