Alpha Structures

In addition to the thermal CVD reactions listed above, tungsten can be deposited by plasma CVD using Reaction(l)at350°C.[ ll P At this temperature, a metastable alpha structure (aW) is formed instead of the stable be.c. Tungsten is also deposited by an excimer laser by Reaction (1) at < 1 Torr to produce stripes on silicon substrate.P l... 

The beta crystalline form of isotactic polypropylene differs from the alpha form by having a lower crystalline density and lower melting point. The beta form is metastable to the alpha form and will rearrange to the alpha structure when heated to approximately 100 °C or placed under strain. Beta lamellae form parallel stacks as shown in Fig. 19.4. 

As a rule, one solid phase of these electrolytes is a fairly good conductor, its open structure allowing the cation (Ag" ", Na ", Li" ") to move fairly freely inside the lattice. In the case of Agl the conductivity, K, increases by two orders of magnitude at 147°C, as the beta-modification is transformed into a more open alpha-structure. At ambient temperature the conductivity of Agl itself is very small, but it is much higher in some complexes. 

Proteins occur as helices (alpha structures) and pleated sheets (beta structures). The alpha structures are dependent on intramolecular hydrogen bonds, whereas the beta structures are dependent on intermolecular hydrogen bonding. 

Fig. 4 Pepplot graphic of secondary structure predictions of the mating pheromones Er-1 (a), Er-2 (b), and Er-10 (c). Dotted lines are used to distinguish the curves for alpha structures from the curves for beta structures. The horizontal dotted and solid lines indicate the minimum levels for predicting beta and alpha structures. The data for Er-1 are taken from ref. 13 and Er-10 from ref. 15 by permission of the American Society of Biochemistry and Molecular Biology and the American Chemical Society, respectively.

B.S. Negrutskii and A.V. El skaya. 1998. Eukaryotic translation elongation factor 1 alpha Structure, expression, functions, and possible role in aminoacyl-tRNA channeling Prog. Nucleic Acid Res. Mol. Biol. 60 47-78. (PubMed)... 

Keller, H., Devchand, P. R., Perroud, M., and Wahli, W. (1997). PPAR alpha structure-function relationships derived from species-specific differences in responsiveness to hypolipidemic agents. Biol Chem 378, 651-655. 

Lower Cretaceous Mannville Group (Alberta, Canada) resulted from biodegradation of petroleum, involving a bacterial fermentation step. Whether a similar scenario can be invoked for the Oseberg calcite is arguable, considering the temperature of calcite formation (90-100°C), which approaches the upper limit for bacterial activity. It is, however, consistent with the early biodegradation of petroleum in the Alpha structure documented by Dahl Yukler(1991). 

Pedder S C (2003). Pegylation of interferon alpha Structural and pharmacokinetic properties. Semin. Liver Dis. 23 19-22. 

These alloys containing 5 to 12 % aluminum have exceUent resistance to impingement corrosion and high-temp)erature oxidation. The corrosion characteristics of aluminum bronzes are related primarily to aluminum content. Alloys with up to 8 % aluminum have face-centered cubic alpha structures and good resistance to corrosion attack. 

The aluminum content is primarily responsible for the microstructure of these bronzes. A single-phase alpha structure is present in alloys containing approximately 8% aluminum. As the aluminum content is increased, other constituents appear in the microstructure. They may be beta, alpha-gamma eutectoid, or a combination, depending on the aluminum content, the cooling rate from solidification, and the heat treatment. An iron-rich intermetallic compoimd is generally formed when iron is added, whereas the addition of nickel above 2% tends to introduce an additional kappa phase. 

Unalloyed titanivun t3q>ically has an annealed alpha structure in wrought, cast, and P/M forms. The yield strength of Grade 1 is comparable to that of fully annesded 304 stainless steel. 

Grade 4 t3q)ically has an annealed alpha structure in wrought, cast, and P/M forms. 

Ti-0.2Pd products t3 ically have an annealed alpha structure. 

Ti-0.3Mo-0.8Ni products typically have an annealed alpha structure. The tensile and yield strengths of Ti-0.3Mo-0.8Ni exceed those of either the Grade 2 alloy or the Grade 7 alloy. Compared to... 

Secondary alpha (or transformed beta) refers to the local or continuous alpha structures that arise during annealing below the transus (or during cooling... 

Oxidation is not of primary concern in heat treating of titanivim, although it may be a problem in sheet-forming operations. Oxygen pickup during heat treatment results in a surface structure composed predominantly of an oxygen enriched alpha phase, which can result in the formation of scale. This condition is detrimental because of the brittle nature of the oxygen-enriched alpha structure, which also is very abrasive to either carbide or hi -speed steel machine tools. At 955 °C (1750 °F), the alpha structure can extend 0.2 to 0.3 mm (0.008 to 0.012 in.)... 

S.M. Clark, S.G. Prilliman, C.K. Erdonmez, A.P. Alivisatos, Size dependence of the pressure-induced gamma to alpha structural phase transition in iron oxide nanocrystals. Nanotechnology 16(12), 2813-2818 (2005)... 

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