Wire colors

As a point of interest, it is possible to form very thin films or membranes in water, that is, to have the water-film-water system. Thus a solution of lipid can be stretched on an underwater wire frame and, on thinning, the film goes through a succession of interference colors and may end up as a black film of 60-90 A thickness [109]. The situation is reminiscent of soap films in air (see Section XIV-9) it also represents a potentially important modeling of biological membranes. A theoretical model has been discussed by Good [110]. 

The most well-known and at the same time the earliest computer model for a molecular structure representation is a wire frame model (Figure 2-123a). This model is also known under other names such as line model or Drciding model [199]. It shows the individual bonds and the angles formed between these bonds. The bonds of a molecule are represented by colored vector lines and the color is derived from the atom type definition. This simple method does not display atoms, but atom positions can be derived from the end and branching points of the wire frame model. In addition, the bond orders between two atoms can be expressed by the number of lines. 

To display properties on molecular surfaces, two different approaches are applied. One method assigns color codes to each grid point of the surface. The grid points are connected to lines chicken-wire) or to surfaces (solid sphere) and then the color values are interpolated onto a color gradient [200]. The second method projects colored textures onto the surface [202, 203] and is mostly used to display such properties as electrostatic potentials, polarizability, hydrophobidty, and spin density. 

In order to represent 3D molecular models it is necessary to supply structure files with 3D information (e.g., pdb, xyz, df, mol, etc.. If structures from a structure editor are used directly, the files do not normally include 3D data. Indusion of such data can be achieved only via 3D structure generators, force-field calculations, etc. 3D structures can then be represented in various display modes, e.g., wire frame, balls and sticks, space-filling (see Section 2.11). Proteins are visualized by various representations of helices, / -strains, or tertiary structures. An additional feature is the ability to color the atoms according to subunits, temperature, or chain types. During all such operations the molecule can be interactively moved, rotated, or zoomed by the user. 

Wire sparklers are wires coated with pyrotechnic composition which are hand-held and produce a gende spray of gold sparks from iron filings. Fountains are cardboard tubes filled with chemical mixtures that produce a spray of color and sparks extending 2—5 m into the air. Roman candles are cylindrical tubes which repeatedly fire colored stars distances of 5—20 m into the air. These items typically contain 5—12 stars. 

While keeping the collected deuterioammonia at dry ice-isopropyl alcohol temperature, lithium wire (10 mg) is added, followed by a solution of 3/3-hydroxy-5a-cholest-7-en-6-one (161 50 mg) in anhydrous tetrahydrofuran (4 ml). The reaction mixture is stirred for 20 min, the cooling bath is then removed and the ammonia is allowed to boil under reflux for 40 min. A saturated solution of ammonium chloride in tetrahydrofuran is added dropwise until the deep blue color disappears and then the ammonia is allowed to evaporate. The residue is extracted with ether and the organic layer washed with dilute hydrochloric acid and sodium bicarbonate solution and then with water. Drying and evaporation of the solvent gives a semicrystalline residue which is dissolved in acetone and oxidized with 8 N chromic acid solution. After the usual workup the residue is dissolved in methanol containing sodium hydroxide (0.2 g) and heated under reflux for 1 hr to remove any deuterium introduced at C-5 or C-7. (For workup, see section II-B). 

Lihou and Maund (1982) used soap bubbles filled with flammable gas which were blown on the bottom of a fireball chamber to form fireballs. A hemispherical bubble was formed on a wire mesh 200 mm above the base of the measuring chamber in order to permit study of elevated sources. The gas bubble was ignited by direct contact with a candle flame, and the combustion process was filmed at a speed of 64 frames per second. The fireball s color temperature was measured. 

All five models for ethane show roughly the same information. The Wire model looks like a line formula in your chemistry textbook, except that all atoms, not just earbons, are found at the end of a line or at the intersection of lines. (The only exception occurs where three atoms lie on a line. Here, a Wire model will not show the exact position of the center atom.) The Wire model uses color to distinguish different atoms, and one, two and three lines to indicate single, double and triple bonds, respectively. 

The Ball and Wire model is identical to the Wire model, exeept that atom positions are represented by small spheres. This makes it possible to identify all atom locations in all molecules. The Tube model is identical to the Wire model, except that bonds, whether single, double or triple, are represented by single colored tubes. The tubes are useful because they better eonvey the three-dimensional shape of a molecule. The Ball and Spoke model is a variation on the Ibbe model atom positions are represented by colored spheres, making it possible to see all atom locations in all molecules. 

Atoms are colored according to type (see table at right). Atoms may also be labelled by selecting Labels (labels may be turned off by selecting Labels a second time). Only wire and ball-and-wire models may be labelled. 

BroDze-blau, n. bronze blue, reflex blue, -draht, tn. bronze wire, -farbe, /. bronze color. -fKrben, n. bronzing. 

Email-belag) m. coating of enamel, -draht) n. enameled wire, -farbe)/. enamel color, -ge-fiisS) n. enameled vessel. -glaS) n. enamel glass, fusible glass, -lack, m. enamel varnish, enamel. 

Strichelchen, n. little stroke or streak, stricheln, v.t. streak shade, hatch (of lines) break (at short intervals)-Strich-farbe, /. (Min.) streak color, streak, -formulierung, /. formula writing with lines or dashes (to represent bonds), -gitter, n. simple line grating, -kreuz, n. cross hairs, cross wires, -kultur, /. streak culture. 

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