Frequently Used Symbols and Abbreviations

These lists contain the symbols and abbreviations most frequently used in this volume, but they are not expected to be exhaustive. Some specialized notation is only defined in the relevant chapter. An attempt has been made to standardize usage throughout the volume as far as is feasible, but it must be borne in mind that the original research literature certainly is not standardized in this way, and some difficulties may arise from this fact. Trivial use of subscripts etc. is not always mentioned in the symbols listed below. Some of the other symbols used in the text, e.g. for physical constants such as h or tt, or for the thermodynamic quantities such as H or S, are not included in the list since they are considered to follow completely accepted usage. 

In the list of symbols, those used at only one specific point in the text are mostly omitted, in order to try and reduce the length of the list, since explanation of their meaning can be found next to the relevant equation. We have also provided a list of frequently used subscripts, a list of abbreviations, and values of important constants and relations derived from these. 

For consistency with the literature, we have generally used the abbreviations, symbols, and units most commonly used in the research community. In most cases, these correspond to those of the original reference. There are, however, many instances where different symbols are used for the same meaning. There are also instances where the same symbol is used for different meanings. A partial list of the more frequently used abbreviations and symbols is given below. 

Frequently used abbreviations and symbols in the textbook are listed in alphabetical order below ... 

In order to provide as much information as possible in reasonable space, abbreviations, symbols, and conventions have been heavily employed. These are given below according to the column in which they are principally used. It is hoped that they will be reasonably understandable without frequent reference to the explanation. 

Sometimes, quantities of dimension one (frequently called dimensionless quantities) are written in mathematical equivalent fonns denoted by special symbols (e.g. % for percent, 10 ) or abbreviations (ppm, parts per million, 10 ). These are often ambiguous, for example, ppt could mean parts per thousand (10 ) or parts per trillion. The latter is also ambiguous since a trilhon can either be 10 (American system of names) or 10. Similarly, the frequently used ppb (parts per billion) is ambiguous since a billion can either be IO (American system) or 10 (European system). Since those quantities of dimension one can always be replaced by a proper fractional expression and ambiguities must be avoided, their use is deprecated (see section 3.10 in [1]). 

Symbols for (physical) quantities, be they variables or constants, are given by a single character (generally Latin or Greek letters) and are printed in italics, e.g., F (force), p (pressure), p (chemical potential), k (Boltzmann constant). Further differentiation is achieved by the use of subscripts and/or superscripts these are printed in italics if it concerns the symbol of a quantity, otherwise in roman type, e.g., cp (specific heat at constant pressure), hp (Planck s constant), Ffu (surface dilational modulus). For clarity, symbols are generally separated by a (thin) space, e.g., F=ma, not ma. Some generally accepted exceptions occur, such as pH, as well as symbols (or two letter abbreviations, rather) for the dimensionless ratios frequently used in process engineering, like Re for Reynolds number and Tr for Trouton ratio (in roman type). 

A short and not too serious look at the name HPLC is followed by a list of frequently used abbreviations and symbols and some tips for newcomers to the subject, including a checklist to be used before doing an HPLC run. Then comes a brief explanation of some important chromatographic expressions. This is intended as a refresher it cannot replace a study of HPLC theory in an appropriate textbook. The main part of the book is a series of Tips , grouped under three headings ... 

Accordii to the International Classification and Nomenclature of enzymes adopted by the Commission of the International Biochemical Union, with the participation of Soviet biochemists, in the abbreviation of the English name of these enzymes and its Russian translation, transfer RNA is given with the symbol (sRNA) from soluble RNA, and not with the symbol t, frequently used in scientific papers. In future, therefore, we shall use the abbreviation sRNA. 

Table footnotes include explanatory material referring to the whole table and to specific entries. Examples of information that should be placed in general footnotes referring to the whole table are the following units of measure that apply to all entries in the table, explanations of abbreviations and symbols used frequently throughout the table, details of experimental conditions if not already described in the text or if different from the text, general sources of data, and other literature citations. 

Abbreviations and acronyms (words formed from the initial letters of groups of words that are frequently repeated) should be used sparingly. Unless they are well established (e.g. NMR, IR) they should always be defined once in any paper, and they should generally be avoided in titles and abstracts. Abbreviations used to denote physical quantities should if possible be replaced by the recommended symbol for the quantity (e.g. E rather than IP for ionization energy, see. p.20 p rather than dens, for mass density, see p.12). For further recommendations concerning abbreviations see [46]. 

Many foreign abbreviations are really a form of shorthand which frequently only the author can decipher. They are not necessarily coined on the basis of any uniform system, and that is where the main difficulty lies. This paper does not solve the difficulties encountered in connection with abbreviations used in the German, French, and Italian chemical literature, nor does it cover foreign abbreviations of journal citations or symbols. It is intended solely to afford an insight into whatever method there is in the madness, and to draw attention to some of the features to watch for as possible clues. Tables I and II list many of these abbreviations. 

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