Solid matrices

To write an unsteady state enthalpy balance we require the enthalpy per unit volume of the gas-permeated solid matrix. This is given by... 

Equations (12.13) and (12.14) may be approximated by rather simple equations in most conditions of physical interest. This is possible because of the relatively large value of the thermal conductivity of the solid matrix, which has two important consequences. First, the conductive enthalpy flux, represented by the second term on the left hand side of... 

Cyclobutadiene itself is not stable at room temperature. Several derivatives with stabilizing groups have been prepared by the acid-catalyzed dimerization of alkjmes (R. Gompper, 1975). Less substituted cyclobutadienes could be obtained by photolytic reactions in solid matrix at low temperatures (G. Maier, 1973, 1974). 

Gravimetric methods based on precipitation or volatilization reactions require that the analyte, or some other species in the sample, participate in a chemical reaction producing a change in physical state. For example, in direct precipitation gravimetry, a soluble analyte is converted to an insoluble form that precipitates from solution. In some situations, however, the analyte is already present in a form that may be readily separated from its liquid, gas, or solid matrix. When such a separation is possible, the analyte s mass can be directly determined with an appropriate balance. In this section the application of particulate gravimetry is briefly considered. 

Two approaches have been used to separate the analyte from its matrix in particulate gravimetry. The most common approach is filtration, in which solid particulates are separated from their gas, liquid, or solid matrix. A second approach uses a liquid-phase or solid-phase extraction. 

Solid samples are separated by particle size using one or more sieves. By selecting several sieves of different mesh size, particulates with a narrow size range can be isolated from the solid matrix. Sieves are available in a variety of mesh sizes, ranging from approximately 25 mm to 40 )j,m. 

Laser action can be induced in Nd ions embedded in a suitable solid matrix. Several matrices, including some special glasses, are suitable but one of the most frequently used is yttrium aluminium garnet (Y3AI5O12), which is referred to as YAG. 

The solid matrix is used most effectively. Authors elaborated two ways of the polymer matrix application ... 

If ionization of a core level X in an atom A in a solid matrix M by a primary electron of energy Ep gives rise to the current Ij (XYZ) of electrons produced by the Auger transition XYZ, then the Auger current from A is... 

The elution volume of sodium nitrate [ Ve (NaN03)] allows one to calculate the volume of solid matrix (V ,) in the column according to... 

The intraporous volumes and solid matrix volumes can be expressed as a percentage of the total bed volumes and should be equivalent to 50-55 and 15-18%, respectively. The solid matrix volume depends on the packing density and can be taken as a qualitative number for the control of the reproducibility of repeated packing procedures. 

MALDI is a LIMS method capable of vaporizing and ionizing large biological molecules such as proteins or DNA. The biological molecules are dispersed in a solid matrix that serves as a carrier. 

R. B. Merrifield (Rockefeller, New York) development of methodology for the synthesis of peptides on a solid matrix. 

Storage in inorganic solid matrix Intercalation into graphite [6,7] Carbon-bromine adduct [4] In zeolites [8]... 

A quite different approach was introduced in the early 1980s [44-46], in which a dense solid electrode is fabricated which has a composite microstructure in which particles of the reactant phase are finely dispersed within a solid, electronically conducting matrix in which the electroactive species is also mobile. There is thus a large internal reactant/mixed-conductor matrix interfacial area. The electroactive species is transported through the solid matrix to this interfacial region, where it undergoes the chemical part of the electrode reaction. Since the matrix material is also an electronic conductor, it can also act as the electrode s current collector. The electrochemical part of the reaction takes place on the outer surface of the composite electrode. 

Kashiwabra, H., Shimada, S., Hori, Y. and Sakaguchi, M. ESR Application to Polymer Physics — Molecular Motion in Solid Matrix in which Free Radicals are Trapped. Vol. 82, pp. 141 -207. 

Oxychlorides are less prolific, apart from the red-brown OsOCl4 (m.p. 32°C). This probably has a molecular structure in the solid state as the IR spectra of the solid, matrix-isolated and gas-phase molecules are very similar, and the volatility is consonant with this [30]. Syntheses include heating osmium in a stream of oxygen/chlorine ( oxychlorination ) and by ... 

A foam is a colloid formed by suspending a gas in a liquid or a solid matrix, while a sol is a suspension of a solid in a liquid. Some examples of foams are styrofoam and soapsuds examples of sols are muddy water and mayonnaise. 

This sample preparation involved, firstly, an extraction and the elimination of the solid matrix by filtration and, secondly, a concentration procedure employing a solid phase extraction cartridge. The compounds of interest were separated solely by dispersive interactions with the reversed phase. In the example given, the corn meal was spiked with the aflatoxins. 

Matrix-assisted laser desorption ionization (MALDI) A method used for the ionization of high-molecular-weight compounds. In this approach, the analyte is crystallized with a solid matrix and then bombarded with a laser of a frequency which is absorbed by the matrix material. 

Chau ASY. 1972. Confirmation of pesticide residue identity V. Alternative procedure for derivative formation in solid matrix for the confirmation of alpha- and beta endosulfan by gas chromatography. J Assoc Off Anal Chem 55 1228-1231. 

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