INDEX stoichiometric

Molinari M, Parker SC, Sayle DC, Islam MS Water adsorption and its effect on the stability of low index stoichiometric and reduced surf es of Ceria, J Phys Chem C 116... 

Concurrent bombardment during film growth affects film properties such as the film—substrate adhesion, density, surface area, porosity, surface coverage, residual film stress, index of refraction, and electrical resistivity. In reactive ion plating, the use of concurrent bombardment allows the deposition of stoichiometric, high density films of compounds such as TiN, ZrN, and Zr02 at low substrate temperatures. 

Formulations should be based on stoichiometric considerations. Based on a knowledge of the hydroxyl value of the polyol the amount of isocyanate necessary to cause chain growth should be calculated. The gas evolved will depend on the water content and additional isocyanate must be incorporated corresponding to the water present. When the isocyanate used equals the theoretical amount the system is said to have a TDI index of 100. In practice a slight excess of isocyanate is used (TDI index 105-110) to ensure complete... 

Nonstoichiometric compounds such as FeO, Ni, xO, LaCo03+8 LaCo03+x/2 etc. are indexed under the notionally stoichiometric phase, i.e. FeO, NiO, LaCo03. 

Dethiobiotin, the sulfur-free analog of biotin, competitively inhibits the growth of O. danica the inhibition index is 10. Biocytin (e-N-biotinyl-L-lysine) stoichiometrically replaced biotin for O. danica. Because O. danica is phagotrophic (A2), it can probably ingest low-molecular forms of biotin, e.g., biocytin. Other forms of biotin were not studied. 

The ability of some fluorescent dyes to bind DNA quantitatively is exploited in flow cytometry to determine the DNA content of a cell. Dyes such as propidium iodide that bind double-stranded DNA stoichiometrically can be used for the purpose. The intensity of red fluorescence is directly related to the amount of DNA bound by propidium iodide. By comparing the fluorescence intensity of the test specimen and, in turn, its DNA content to the fluorescence intensity of specimens containing normal diploid amounts of DNA, a DNA histogram can be generated. By computing a DNA index, which is the ratio of DNA content of a test specimen to the DNA content of a specimen containing a normal diploid population, information related to the presence of an aneuploid tumor population can be obtained. The DNA index of 1 would imply that the DNA in the test specimen is from a normal diploid population (2N DNA), whereas the DNA index of an aneuploid population will be greater or less than 1. Thus, the DNA index of a tetraploid (4N DNA) would be 2. 

Components are the most basic units (molecules or ions or atoms) that interact with each other. In the above example X, Y, and Z are components. All the resulting products of the interactions (molecules or ions or complexes) are called species. In the example, one of potentially many species is XxYyZz. To be consistent and to allow elegant and efficient notation and computer coding, the components themselves are also species. Their equilibrium constant is one. The equilibrium constants fixyz as defined in (3.22) are called formation constants. The composition of a particular species is defined by a set of three stoichiometric constants written as the indices x, y, and z. If a species is composed of only two components, the appropriate index is zero. 

For the case of benzene (C6H6) burning in air, the mass stoichiometric index i is found to be... 

Thus, the overall thermodynamic steps required to calculate the mass stoichiometric index in Eq. (9.29) are... 

Studies of the reaction of ozone with simplified lipid systems have shown that malonaldehyde can be produced by direct ozonolysis. The use of malonaldehyde assay as an index of lipid peroxidation is therefore invalid in ozone studies. Liposomes formed from egg lecithin and prepared in aqueous media were quite resistant to ozone, but the contribution of polyconcentric spheres to this resistance has not been fully assessed. However, the bilayer configuration, with the susceptible unsaturated fatty acids shielded from ozone by the hydrophilic areas of the molecule, may be resistant. In hexane, where the fatty acid moieties are exposed, ozone reacts stoichiometrically with the double bonds. The experiments with aqueous suspensions of phosphatidylcholine gave no evidence of the formation of lipid peroxides,nor did experiments with films of fatty acids exposed to ozone. ... 

An isolated cs plane or a random array of cs planes, known as the Wadsley defect, still gives rise to nonstoichiometry. Regularly recurring cs planes result in a homologous series of stoichiometric intermediate phases. Occurrence of such equidistant cs planes in a crystal indicates a cooperative mechanism. The formula of a cs phase depends on the cs plane index as well as the width of the parent slab between cs planes. If MO is the formula of the parent line phase, the formula of the homologous series of oxides resulting from cs may be represented as where n is the width (number of... 

Equation 9.72 introduces a great deal of nomenclature at once. Chemical species are indexed by k, with K being the total number of species (later, when we generalize the kinetics to multiple phases, the variable Kg is used for the number of gas-phase species) reactions are indexed by the variable i, with / being the total number of reactions in the mechanism the name of species k is represented by X v ki is the stoichiometric coefficient of species k in the forward direction of reaction i is the stoichiometric coefficient of species k in the reverse direction of reaction i. 

The microkinetics of the chemical reaction that takes place is described by da/dt = dbd/dt = —kaabd where kt> is the real chemical reaction rate constant and the index d refers to the dispersed phase. If the components A and B are supplied to the reactor in stoichiometric quantities and... 

Here c(x, t)dx is the concentration of material with index in the slice (x, x + dx) whose rate constant is k(x) K(x, z) describes the interaction of the species. The authors obtain some striking results for uniform systems, as they call those for which K is independent of x (Astarita and Ocone, 1988 Astarita, 1989). Their second-order reaction would imply that each slice reacted with every other, K being a stoichiometric coefficient function. Only if K = S(z -x) would we have a continuum of independent parallel second-order reactions. In spite of the physical objections, the mathematical challenge of setting this up properly remains. Ho and Aris (1987) have shown how not to do it. Astarita and Ocone have shown how to do something a little different and probably more sensible physically. We shall see that it can be done quite generally by having a double-indexed mixture with parallel first-order reactions. The first-order kinetics ensures the individuality of the reactions and the distribution... 

The conservation law may also be applied to each individual sort of atom. Let us have g sorts of molecules (the first index), consisting of / sorts of atoms (the second index), then we characterize the composition of the molecules by the stoichiometric numbers vit (the number of atoms of sort l in a molecule of sort i). Conservation of the atoms of a given sort l is written thus ... 

We see from Eq. (15.3) that either the v, s or e must be expressed in molest and that the other quantity must be a pure number. As a matter of convenience we choose to express the reaction coordinate e in moles. This allows one to speak of a mole of reaction, meaning that e has changed by a unit amount, i.e., by one, mole. When Ae = 1 mol, the reaction proceeds to such an extent that the chaise in mole number of each reactant artd product is equal to its stoichiometric number. When two or more independent reactions proceed simultaneously, we let subscript j be the reaction index, and associate a separate reaction coordinate with each reaction. The stoichiometric numbers are doubly subscripted to identify , their association with both a species and a reaction. Thus designates th stoichiometric number of species i in reaction j. Since the number of moles of i species n,- may change because of several reactions, the general equation analogous to Eq. (15.3) includes a sum ... 

A negative stoichiometric index indicates that a material is consumed a positive index indicates that it is produced in the reaction. A screening environmental index is used for comparison in Tier I assessment Environmental... 

From these examples the rules of nomenclature are apparent. The central atom (like Fe, Cu, Co, Ag) is followed by the formula of the ligand (CN, NH3, H20, S203), with the stoichiometric index number, (which, in the case of monodentate ligands is equal to the coordination number). The formula is placed inside square brackets, and the charge of the ion is shown outside the brackets in the usual way. When expressing concentrations of complexes, brackets of the type will be used to avoid confusion. In the name of the ion, first the (Greek) number, then the name of the ligand is expressed, followed by the name of the central atom and its oxidation number (valency). 

Each entry must have a numerical factor corresponding to the stoichiometric coefficient of the species considered (index of r). 

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