Array elements

In order to perform a database search the structural key of the query molecule or substructure is compared with the stored structural keys of the database entries. This implies that each array element in the structural key has to be defined initi-... 

II energy values where the energy is between Ef j and E and where the value of the opriate array element H( ) is greater than some minimum value (e.g. 20). In other is, that particular energy level must have been visited at least twenty times during iimulation. The following two parameters are now calculated ... 

The periodic table is the most important chemistry reference there is. It arranges all the known elements in an informative array. Elements are arranged left to right and top to bottom in order of increasing atomic number.. This order generally coincides with increasing atomic mass... 

Consider two array elements as illustrated in Figure 29.3, and suppose an ion beam has been dispersed to give ions of m/z values 100 and 101. If the dispersion is correct for the array size, the... 

Ions of 5 different m/z values dispersed in space and entering 4 of the array elements... 

An array ion collector (detector) consists of a large number of miniature electron multiplier elements arranged side by side along a plane. Point ion collectors gather and detect ions sequentially (all ions are focused at one point one after another), but array collectors gather and detect all ions simultaneously (all ions are focused onto the array elements at the same time). Array detectors are particularly useful for situations in which ionization occurs within a very short space of time, as with some ionization sources, or in which only trace quantities of a substance are available. For these very short time scales, only the array collector can measure a whole spectrum or part of a spectrum satisfactorily in the time available. 

There is potential confusion in the use of the word array in mass spectrometry. Historically, array has been used to describe an assemblage of small single-point ion detectors (elements), each of which acts as a separate ion current generator. Thus, arrival of ions in one of the array elements generates an ion current specifically from that element. An ion of any given m/z value is collected by one of the elements of the array. An ion of different m/z value is collected by another element. Ions of different m/z value are dispersed in space over the face of the array, and the ions are detected by m/z value at different elements (Figure 30.4). 

The arrival of ions at the opening of one of the array elements causes a shower of electrons to pass to the end of the collector, where they are recorded as a current flow, which is usually amplified. 

The magnitude of the current flow is proportional to the number of ions arriving at the array element per unit time. 

Array—A collection of data items of the same type, referred to collectively by a. single name. The individual items, the array elements, are ordered by... 

Assignment—As>s gn a value, either a constant or a computed value, to a variable, an array element, a node, or a field. 

Pascal names (of units, variables, array elements, etc.), consisting of an initial letter followed by letters or digits, may be as long as needed in standard Pascal however, in practice, most compilers require that a name be unique within a certain number of characters. (See Table 1-28 for reserved words which may not be used as names.)... 

Array—May have more than one dimension number of dimensions and type are assigned at declaration and may not be changed values are assigned to array elements (which must be of same type) as they are to variables. 

Assignment statements—Assign values by numerical or character constants, by expressions (see Table 1-29 for arithmetic and set operators), or by input to variables, array elements, and fields... 

Young s Interference Experiment (1.5) A Young s interferometer basically consists of a stop with two holes ( array elements ), illuminated by a distant point source, and a screen which picks up the light at a sufficiently large distance behind the holes. The light patch produced by the stop is extended and shows a set of dark fringes which are oriented perpendicularly to the direction which connects the centers of the two openings. 

The calculation with variable layer thickness is straightforward in principle but requires some care in application. I introduce a number of new arrays that specify layer thicknesses, separations, and depths, as illustrated in Figure 8-3. The values of these arrays elements are calculated in subroutine SPECS. 

Such a system would include a program similar to that of Storer and Comish-Bowden to do equilibrium calculations. A communication-control subprogram would be Hiked to an expert model by using the EXPERT knowledge-base shall (or system-builder) which is advantageous here because it can interact with procedures such as those written in FORTRAN for numerical computation. Additional programs and a small data base, which EXPERT can handle, would keep track of which chemical was what array element, and other requirements mentioned above. 

Starting at line 900 you find the user subroutine. In this routine the mole numbers occupy the array elements NW(1), NW(2),. .., NW(5) and the scalar variable NW stores the total mole number. At the current value X(l) and X(2) of the reaction extents we first calculate tine mole numbers. If any of them is negative or zero, the error flag ER is set to a nonzero value. If the mole numbers are feasible, the values computed according to (2.31) will occupy the array elements G(l) and G(2). The initial estimates are X(1) = 1 and X(2) = 0.1, the first corrections are D(l) = D(2) = 0.01. The following output shows some of the iterations. 

Reliability Large numbers of redundant sensors allow signal averaging to improve accuracy and the use of fault detection algorithms to detect the failure of individual array elements.36 For example, the variance of a measurement based on the average of N identical sensors is... 

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