Contract meaning

Of course, the fascinating steric features of lanthanide elements are most impressively expressed in the lanthanide contraction [76]. In textbooks, lanthanide contraction is often simply explained as being the phenomena responsible for similar chemical properties, in particular between the pairs of the d-transition metal homologues Zr/Hf, Nb/Ta and Mo/W. However, what does the contraction mean to the lanthanide elements (and compounds derived from them)... 

For A T < 0, Ap must contract, while for A T > 0, Ap must expand, where the contraction means an increase of low momentum density with a simultaneous decrease of high momentum density and the expansion means the density reorganization reverse to the contraction. 

From a practical point of view one has to decide whether one chooses a contracted [152, 153] or uncontracted excitation scheme. In the latter the number of excitations to include is tremendous, in the former one must find a way how to deal with the so-called excitations with spectator-lines (unless one neglects these, which appears to be justified to some extent). Contracted means that one considers formal single, double etc. excitations with respect to the full MC-SCF wave function e.g. uncontracted means that... 

Abstract This chapter discusses the chemical and physical properties of the lanthanides, some of which are in a certain way peculiar. It discusses the oxidation states of the REE, and the phenomenon called the lanthanide contraction (meaning that the atomic radius decreases with increasing atomic number in the series lanthanum-lutetium). It lists the isotopes known per element, and explains the radioactivity of promethium, the only element of the rare earths that has only radioactive isotopes and no stable isotopes. Magnetism and luminescence also are discussed. 

Similarly, for the change in cationic size with constant charge, as in the lanthanides (where the lanthanide contraction means that the elements with higher atomic numbers give the smallest 3+ ions) where only the metal ion changes, we generally find the stability of a series of coordination compounds to increase from lanthanum (atomic number 57) to lutetium (atomic number 71). 

Here the term contract means a contractual relationship between the university and firms or other institutions, which might take the form of a research contract, research collaboration, grant, provision of services or some other type of contract not included in the above categories. In the text we use the term contracts to embrace all these categories, unless otherwise indicated in the analysis of the particular nature of the contractual relationship. 

Another family of basis sets, commonly referred to as the Pople basis sets, are indicated by the notation 6—31G. This notation means that each core orbital is described by a single contraction of six GTO primitives and each valence shell orbital is described by two contractions, one with three primitives and the other with one primitive. These basis sets are very popular, particularly for organic molecules. Other Pople basis sets in this set are 3—21G, 4—31G, 4—22G, 6-21G, 6-31IG, and 7-41G. 

An older, but still used, notation specihes how many contractions are present. For example, the acronym TZV stands for triple-zeta valence, meaning that there are three valence contractions, such as in a 6—311G basis. The acronyms SZ and DZ stand for single zeta and double zeta, respectively. A P in this notation indicates the use of polarization functions. Since this notation has been used for describing a number of basis sets, the name of the set creator is usually included in the basis set name (i.e., Ahlrichs VDZ). If the author s name is not included, either the Dunning-Hay set is implied or the set that came with the software package being used is implied. 

Phosphodiesterase Inhibitors. Because of the complexity of the biochemical processes involved in cardiac muscle contraction, investigators have looked at these pathways for other means of dmg intervention for CHF. One of the areas of investigation involves increased cycHc adenosine monophosphate [60-92-4] (cAMP) through inhibition of phosphodiesterase [9025-82-5] (PDE). This class of compounds includes amrinone, considered beneficial for CHF because of positive inotropic and vasodilator activity. The mechanism of inotropic action involves the inhibition of PDE, which in turn inhibits the intracellular hydrolysis of cAMP (130). In cascade fashion, cAMP-catalyzed phosphorylation of sarcolemmal calcium-channels follows, activating the calcium pump (131). A series of synthetic moieties including the bipyridines, amrinone and milrinone, piroximone and enoximone, [77671-31-9], C22H22N2O2S, all of which have been shown to improve cardiac contractiUty in short-term studies, were developed (132,133). These dmgs... 

Tolling means to provide manufacturing services for a fee by a contractor (the toller), to a company issuing (letting) a contract for those services. Tolled services can include ... 

Full consideration of the thermal expansion of the tubes is necessary, with adequate provision for expansion and contraction. It is a wise policy to fit thermometer wells in the pipes near the inlets and outlets of all airheating batteries, as these provide a useful means of checking the coil performance. 

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