Prefixes standardized conventions

Prefixes may be added to the unit as a matter of practice and, in many cases, they are standardized conventions of particular fields. For instance, the unit MW is common to the power industry. The unit nm is used in crystallography for the physicochemical characterization of solids—pore diameter is an example. All prefixes are multiples of ten and are summarized in Table 1.4. The symbol is capitalized for multiple factors greater than 10. The symbols for 10 and 10 " are the same as for 10 and 10 ", the only difference being the former are capitalized and the fraction factors are in lower case. The only Greek letter used as a symbol is for lO" "—micro—and the only two-letter symbol is da (which is rarely used in practice, especially combined with meters). 

Sometimes the subscript s or g is added to a d or l prefix to indicate whether the chirality of a compound is being related to that of serine, the traditional configurational standard for amino acids, or to that of gly-ceraldehyde. In the latter case the sugar convention (Chapter 4) is followed. In this convention the configurations of the chiral centers furthest from Cl are compared. Ordinary threonine is ls- or d -threonine. The configuration of dextrorotatory (+)-tartaric acid can be described as 2R, 3R, or as ds, or as l. ... 

Where there is more than one kind of substituent, the prefixes are cited in alphabetical order before the name of the parent hydride, parentheses being used to avoid ambiguity, and multiplicative prefixes being used as necessary. Non-standard bonding numbers are indicated using the. -convention (see Section IR-6.2.2.2). An overview of the rules for naming substituted derivatives of parent hydrides is given in Section IR-6.3, while a detailed exposition may be found in Ref. 3. 

In principle, all radicals and ions can nowadays be named in a uniform and totally systematic manner on the basis of the operational suffixes (and prefixes derived therefrom) compiled in Table 11. Obviously, standardization of the nomenclature for such derived species can be fully congruous only if the names of the underlying parent structures themselves are generated in a thoroughly systematic way, e.g. oxidane, dioxidane, azane, diazane, etc. Hence, in the subsequent sections fully systematic names are always given as well as the conventional trivial/traditional designations. 

The conventional notation for referring to an entry in the G[] table, such as the type() function would be the eode G.typeQ. This will certainly invoke the typeQ function. However, for simplicity Lua accepts references to entries in the G[] table without the G prefix so that the eode statement type() can be used to invoke the function. For the other tables in the G[] table, the standard Lua access methods must be used. For example to invoke the sin() function within the math[] table, the proper Lua code statement is math.sin() . Another example is os.eloekO to get information about the time for use in timing the execution of a block of code. To simplify notation one can define additional names such as sin = math.sin so that the sin function can be accessed by the statement sin(). 

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