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Structures formed

Chromium dioxide. Cr02 (HjO plus O2 on Cr03 at high temperature). Black solid with the rutile structure forming chromates(IV) in solid stale reactions. Used in magnetic lap>es. [Pg.99]

Other interesting Langmuir monolayer systems include spread thermotropic liquid crystals where a foam structure forms on expansion from a collapsed state [23]. Spread monolayers of clay dispersions form a layer of overlapping clay platelets that can be subsequently deposited onto solid substrates [24]. [Pg.542]

Tochihara H and Mizuno S 1998 Composite surface structures formed by restructuring-type adsorption of alkali-metals on FCC metals Prog. Surf. Sc/. 58 1... [Pg.318]

Figure 27. Top One of the allylic type-VI structures, formed by in-phase combination of type-V structures, Bottom The 6ve type-VI structures,... Figure 27. Top One of the allylic type-VI structures, formed by in-phase combination of type-V structures, Bottom The 6ve type-VI structures,...
It may be desirable to predict which crystal structure is most stable in order to predict the products formed under thermodynamic conditions. This is a very difficult task. As of yet, no completely automated way to try all possible crystal structures formed from a particular collection of elements (analogous to a molecular conformation search) has been devised. Even if such an effort were attempted, the amount of computer power necessary would be enormous. Such studies usually test a collection of likely structures, which is by no means infal-... [Pg.270]

Have any ring structures formed from the reaction of two ends of the same molecule ... [Pg.31]

Production of useful structural forms, as in pressing of intricate shapes in powder metallurgy. [Pg.1876]

Inteimediate purity. 50 to 55 percent alumina. The anorthite (needle-structure) form is more resistant to the action of steam exposure. [Pg.2478]

Early diffraction photographs of such DNA fibers taken by Rosalind Franklin and Maurice Wilkins in London and interpreted by James Watson and Francis Crick in Cambridge revealed two types of DNA structures A-DNA and B-DNA. The B-DNA form is obtained when DNA is fully hydrated as it is in vivo. A-DNA is obtained under dehydrated nonphysiological conditions. Improvements in the methods for the chemical synthesis of DNA have recently made it possible to study crystals of short DNA molecules of any selected sequence. These studies have essentially confirmed the refined fiber diffraction models for A- and B-DNA and in addition have given details of small structural variations for different DNA sequences. Furthermore, a new structural form of DNA, called Z-DNA, has been discovered. [Pg.121]

Serine proteinases such as chymotrypsin and subtilisin catalyze the cleavage of peptide bonds. Four features essential for catalysis are present in the three-dimensional structures of all serine proteinases a catalytic triad, an oxyanion binding site, a substrate specificity pocket, and a nonspecific binding site for polypeptide substrates. These four features, in a very similar arrangement, are present in both chymotrypsin and subtilisin even though they are achieved in the two enzymes in completely different ways by quite different three-dimensional structures. Chymotrypsin is built up from two p-barrel domains, whereas the subtilisin structure is of the a/p type. These two enzymes provide an example of convergent evolution where completely different loop regions, attached to different framework structures, form similar active sites. [Pg.219]

It is likely that the quinone methide and related structures formed at these temperatures account for the dark colour of phenolic compression mouldings. It is to be noted that cast phenol-formaldehyde resins, which are hardened at much... [Pg.642]

Among the alkali metals, Li, Na, K, Rb, and Cs and their alloys have been used as exohedral dopants for Cgo [25, 26], with one electron typically transferred per alkali metal dopant. Although the metal atom diffusion rates appear to be considerably lower, some success has also been achieved with the intercalation of alkaline earth dopants, such as Ca, Sr, and Ba [27, 28, 29], where two electrons per metal atom M are transferred to the Cgo molecules for low concentrations of metal atoms, and less than two electrons per alkaline earth ion for high metal atom concentrations. Since the alkaline earth ions are smaller than the corresponding alkali metals in the same row of the periodic table, the crystal structures formed with alkaline earth doping are often different from those for the alkali metal dopants. Except for the alkali metal and alkaline earth intercalation compounds, few intercalation compounds have been investigated for their physical properties. [Pg.38]

Colloidal crystals . At the end of Section 2.1.4, there is a brief account of regular, crystal-like structures formed spontaneously by two differently sized populations of hard (polymeric) spheres, typically near 0.5 nm in diameter, depositing out of a colloidal solution. Binary superlattices of composition AB2 and ABn are found. Experiment has allowed phase diagrams to be constructed, showing the crystal structures formed for a fixed radius ratio of the two populations but for variable volume fractions in solution of the two populations, and a computer simulation (Eldridge et al. 1995) has been used to examine how nearly theory and experiment match up. The agreement is not bad, but there are some unexpected differences from which lessons were learned. [Pg.475]

As with chemical etches, developing optimum conversion coatings requires assessment of the microstructure of the steel. Correlations have been found between the microstructure of the substrate material and the nature of the phosphate films formed. Aloru et al. demonstrated that the type of phosphate crystal formed varies with the orientation of the underlying steel crystal lattice [154]. Fig. 32 illustrates the different phosphate crystal morphologies that formed on two heat-treated surfaces. The fine flake structure formed on the tempered martensite surface promotes adhesion more effectively than the knobby protrusions formed on the cold-rolled steel. [Pg.991]

Vesicles Spherical structures, formed intracellularly, by some arbuscular mycorrhizal fungi. [Pg.628]

Ex-Target Tree. (EXTGT Tree) A branching tree structure formed by retrosynthetic analysis of a target molecule (treetop). Such trees grow out from a target and consist of nodes which correspond to the structures of intermediates along a pathway of synthesis. [Pg.96]

Figure 1 shows some of the typical structural parameters of CNT generated in our laboratory. On the average, we can think that an MWCNT is a 1 micron long structure formed by about 10-15 concentric graphitic cylinders, the external one with a diameter of 12 nm, and the innermost tube has a diameter of about 2 nm. Hence, these tubes can be used as templates, the generated enclosed wires would have dimensions of a few nm in diameter when filled, or a few tens of nm when CNTs are covered with materials. [Pg.130]

In a somewhat wider sense, one can define amphiphiles as molecules in which chemically very different units are linked together. For example, the structures formed by A B block copolymers in demixed A and/or B homopolymer melts and their phase behavior are very similar to those of classical amphiphiles in water and/or oil [13,14]. Copolymers are used not only to disperse immiscible homopolymer phases in one another, but also to create new, mesoscopically structured materials with unusual and interesting properties [15]. [Pg.635]

The structure formation in an ER fluid was simulated [99]. The characteristic parameter is the ratio of the Brownian force to the dipolar force. Over a wide range of this ratio there is rapid chain formation followed by aggregation of chains into thick columns with a body-centered tetragonal structure observed. Above a threshold of the intensity of an external ahgn-ing field, condensation of the particles happens [100]. This effect has also been studied for MR fluids [101]. The rheological behavior of ER fluids [102] depends on the structure formed chainlike, shear-string, or liquid. Coexistence in dipolar fluids in a field [103], for a Stockmayer fluid in an applied field [104], and the structure of soft-sphere dipolar fluids were investigated [105], and ferroelectric phases were found [106]. An island of vapor-liquid coexistence was found for dipolar hard spherocylinders [107]. It exists between a phase where the particles form chains of dipoles in a nose-to-tail... [Pg.764]

During this stage of the qualitative analysis, a PIF analysis is performed that considers those factors which will determine the probability of error for the type of task under consideration. A structured form of PIF analysis such as the HFA tool described in Section 2.7.2 will facilitate this process. [Pg.212]

Add a suitable detergent reduce the salt concentration to avoid hydrophobic interactions or switch from structure-forming salts (phosphate sulfate) to chlorides or acetates... [Pg.244]

Electrostatic effects have long been recognized in commercial HPLC columns for SEC of proteins (15,21,22). The usual remedy is to add 100 mM salt to the mobile phase. This works here too the Lys and Asp peaks collapse into the Gly peak with 100 mM salt (Eig. 8.8). High concentrations of sodium sulfate were added to determine the role played in SEC by hydrophobic interactions (sodium sulfate, a structure-forming salt, strengthens such interactions). Sodium sulfate increased the retention only of the most hydrophobic amino acids to any extent, and then only when the concentration approached 1 M. Clearly, hydrophobic interaction cannot account for the elution order of amino acids on PolyHEA. [Pg.257]

Note that the structural form of each compound is implied by the presence (T-shaped structure) or absence (distorted structure) of the perturbed asymmetric stretching mode at about 550 cm . [Pg.133]

FIGURE 6.22 The hydroxypyridiiiium structure formed by the cross-liukiug of a Lys aud two hydroxy Lys residues. [Pg.179]

FIGURE 6.34 Sheet structures formed from andparallel arrangements of /3-strands, (a) Streptomyces suh i x Xu inhibitor, (b) glutathione reductase domain 3, and (c) the second domain of glyceraldehyde-3-phosphate dehydrogenase represent minimal andparallel /S-sheet domain structures. In each of these cases, an andparallel /S-sheet is largely exposed to solvent on one face and covered by helices and random coils on the other face. (Jane Richardson)... [Pg.190]

Amphipathic lipids spontaneously form a variety of structures when added to aqueous solution. All these structures form in ways that minimize contact between the hydrophobic lipid chains and the aqueous milieu. For example, when small amounts of a fatty acid are added to an aqueous solution, a mono-layer is formed at the air-water interface, with the polar head groups in contact with the water surface and the hydrophobic tails in contact with the air (Figure 9.2). Few lipid molecules are found as monomers in solution. [Pg.261]


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See also in sourсe #XX -- [ Pg.508 ]




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A Selection of Cyclic Hydrogen-Bonding Patterns Formed in Nucleoside and Nucleotide Crystal Structures

Aluminosilicates with Sheet Structures that Form Fibers

Amphiphilic Polymers Forming Micelle Analogous Structures

An Organic Channel Structure Formed by the Supramolecular Assembly of

Benzene structural forms

Bicontinuous structures form, amphiphile

Bicontinuous structures form, amphiphile aggregate structure

Bilayer membranes Structure formed

Carbon as Structure-Forming Element in Porous Fuel Cell Electrodes

Cavity-forming structures

Condensed form, organic structures

Crystal Structure of the a Form

Crystal Structure of the p Form

Crystal Structures of Mesogens That Form Nematic Mesophases

Crystal structures 3-form

Crystal structures smectic form

DNA, forms double helical structure

DNA, forms right-handed helical structure

DNA, forms tetraplex structures

Dynamical structure factor, glass-forming

Electronic structures forming

Entropy, glass-forming liquids structure

Excipients structure-forming

Fiber-forming polymers structures

Fluid structure-forming

Form function of a few characteristic structures Behaviour for large wave vector transfer

Forming helical structures

Forms a Unique Triple-Stranded Structure

Forms, structural properties, intermolecular

Forms, structural properties, intermolecular interaction

Fructose hemiketal form, structure

Globular Protein Structures Are Extremely Varied and Require a More Sophisticated Form of Analysis

Globular proteins, structure-forming

Graphical data structure forms

Graphite structural forms

Hybrid Structures Formed by Lead 1,3-Cyclohexanedicarboxylates

Indicator Chelate-Forming Chemical Structures

Ions structure-forming

Lewis Structures and Resonance Forms

Methadone, structure forms

Micelle forming block copolymers chemical structure

Mimic pore-forming structure

Mobility and Form of Molecules in Relation to Lattice Structure

More complex structures formed by the Langmuir-Blodgett technique

Multiple forms structures

Navigating the Solid Form Landscape with Structural Informatics

Phospholipids Spontaneously Form Ordered Structures in Water

Polymers Formed from Self-Assembled Structures

Quantum wire structures, formed

Reconstituted channels, structural form

Replicative form secondary structure

Replicative form structure

Resonance structures (canonical forms

Sheet forming three-dimensional structure

Structural forms

Structural forms

Structural relaxation time molecular glass-forming liquids, temperature

Structure and Conformation of Selected Gel-forming Polysaccharides

Structure of a-Class Carbonic Anhydrase from Human Erythrocytes (the High Activity form HCA II)

Structure well oriented form

Structure-forming effect, types

Structure-forming factors

Structure/Logic Intermediate Form

Structures Can Form Supercoils

Structures Formed by Backbiting in Ethylene Copolymerization

Structures Formed by the Close Packing of Spheres

Structures forming

Structures forming

Structures of Membrane-forming Substances

Synthetic, mimic pore-forming structure

The fi-Keratins Form Sheetlike Structures with Extended Polypeptide Chains

Thermotropic liquid-crystal-forming molecules, structure

WATER MOLECULES FORM AN OPEN CRYSTALLINE STRUCTURE IN ICE

Water phospholipid structures formed

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