Line drawings, computer

Using computers to display molecular structure is an attractive alternative to traditional line drawings for several reasons. First, the model displayed on a computer screen looks and behaves more like a real molecule than a drawing does. The computer model can be viewed from different angles, and different display formats can be used to show atomic positions, atomic volumes, and other features of interest. Second, the computer can produce a good model even when the student does not know how to make an accurate drawing. Thus, the student, working with a computer, can explore new areas of chemistry ... 

Figure 4. Computer line drawings (without hidden line removal) of three representatives of the I-WP family of constant mean curvature surfaces. These surfaces are invoked to describe the polar/apolar dividing surface in the DDAB / water / hydrophobe cubic phases, at water volume fractions of a) 35% b) 47% c) 65%.

FIGURE 15.22. Assembly of subunits in proteins. Shown are two subunits of the enzyme D-xylose isomerase, forming a dimer by a one-armed embrace. (a) Line drawing connecting Co, carbon atoms, and (b) computer-generated view of the molecule with atoms with van der Waals radii on each Co, carbon atom. No side chains are shown in either diagram. In (a) one monomer is illustrated with black spheres, and the other with white spheres, in order to differentiate between them. (Courtesy H. L. Carrell)... 

Without the support of the University of Victoria, the Department of Chemistry, and my family to work within, this book would never have been completed. I owe a debt of gratitude to the inexhaustible patience of my wife, who handled the whole of the initial inputting of the manuscript into the computer, corrected several drafts, and executed all of the original line drawings. Thanks also go to K. Hartman who did the photographic work, to B.J. Hiscock and L. J. Proctor, who unfailingly encouraged adoption of the computer for manuscript preparation, and to L.G. Charron and M. Cormack, who completed the final manuscript. 

The American Chemical Society (ACS) publishes 19 primary journals. Chemical Abstracts (CA), computer-readable and on-line data bases, and many other publications in chemistry. Chemical Abstracts Service (CAS), a division of the ACS located in Columbus, Ohio, does most of the computer processing and software development for these publications and data bases. ACS publications and data bases contain chemical structures, tables, equations, line drawings, and other images. CAS continues to automate the processing of graphics for both printed publication and on-line data base publication. 

Transparency Set (0-13-147878-8) This package comprises 275 four-color acetates of the most useful images, computer art, and line drawings from the text The Transparency Pack is available at no charge to adopters of Organic Chemistry, Sixth Edition. 

The selection set is a presentation of the items from which the user makes choices. The elements in the selection set correspond to the elements of a specific activity output. Selection sets may have written letters, words and sentences, symbols used to represent ideas, computer icons, or line draw-ings/pictures. They may be presented in visual (e.g., letters on keys), tactile (e.g., Braille), or auditory (e.g., voice synthesis) form. We can define two selection methods through which the user makes selections using the control interface direct selection and indirect selection (Cook and Hussey, 2(X)2). For any particular application, the three elements of the human-technology interface will be chosen based on the best match to the consumer s skills (motor, sensory, linguistic, and cognitive) (Cook and Hussey, 2002). 

The PPR method (cf. Section 2.6.1.4) uses the ratio of two neighboring signals. In contrast, the side-peak-side ratio (SPSR) method [68] uses only one peak, as can be seen in Fig. 2-31. The SPSR method is of advantage if only one wavelength position is to be located. It represents a special variant of the PPR method. The results of computation can be presented either in tabular form [62, 64] or graphicallly, with a very distinct line drawing [68, 69]. Moreover, the data are normalized in a similar manner to the PPR... 

Molecular structures are commonly drawn in the form of lines representing the bonds between atomic centers. The atoms are only represented as junctions of these lines. These drawings may be referred to as line models, Dreiding models, or wire-frame representations. The bonds of the molecules can be color coded, for example, by the atom types, and single, double, or triple bonds can be represented by one, two, or three lines, respectively. Smooth lines on computer displays can be achieved by using a method called antialiasing . A wire-frame representation of a tryptophane molecule is shown in Figure 1(a). 

Fig. 3.1 Elongation from recorded video frames. Inset a In the first video frame a region of interest (ROI) with fiducial marks is defined. Inset b From the ROI the 2D correlation function y2(x, ) ) is computed. Main drawing The center of the long period peak in yi(x) = yi(x, 0) is fitted by a parabola dashed line) to compute the distance between the fiducial marks [2]...

Finally I thank my wife not only for her patience and encouragement but also for computer programming and curve plotting, for tracing the line drawings of most of the figures, and for a true labour of love in typing the whole manuscript. 

You can specify the number and values of visible contour lines. You specify the total number of contour lines to be shown by simple stating the number, n>0. You normally specify the values of the contour lines as default values. For this case, HyperChem computes the maximum and minimum values on the grid and then draws contours at these values plus n-2 contour lines evenly spaced in between these maximum and minimum values. If you need non-default values, you can specify the starting value and then an increment to define the other n-1 evenly spaced contour lines. If default values were computed previously, HyperChem suggests the starting value and increment of the previous default computation for the new non-default option. 

Figure 2. Schematic drawing of the AEl IM-20 ion microprobe. The magnetic analyzer and ion counting system are linked to an on-line computer for automated...

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