Comparison of Properties

The electronic properties of silicon and other semiconductor materials are shown in Table 13.2. 

The semiconductor properties of a material shown above can be summarized in two figures of merit shown in Table 13.3. 

The Johnsonfigure of merit, based on saturated carrier velocity and dielectric strength (product of power x frequency squared x impedance), predicts the suitability of a material for high power applications. It is normalized with the value of one given to silicon. As shown in Table 13.2 below, diamond is clearly the preferred material on this basis. 

The Keyes figure of merit, based on thermal conductivity as an additional factor, (see following section) predicts the suitability of a semiconductor for dense logic circuit applications. Again, diamond is far superior to other materials. 

Although silicon cannot compete with other semiconductor materials in specific areas, it is overall an excellent material, a fact amply shown by its dominance of the market for the last forty years. It is readily available with a high degree of purity and relatively low cost. Most IC s are made from silicon and this is likely to remain so for some time. 1 1 

The mechanical and physical properties of common plastics and metallic materials are compared in Table 13.1. 

Tests of a different nature and purpose are used to examine manufactured components and assemblies for internal flaws and faults and surface cracks and defects without destroying the component. These tests are known as nondestructive tests (NDT), since the component is not physically damaged as a result of the test and therefore remains fit for purpose. These tests are carried out to check possible defects produced during machining, welding, casting and heat treatment and are also carried out on in-service component s, e.g. jet engine turbine blades and aircraft components. 

Non-destructive evaluation (NDE) is a term often used together with NDT. However, NDE is used to describe measurements that are more quantitative in nature, i.e. detection of the defect is not enough, quantitative information is required regarding flaw size, shape and orientation, information which could be used to determine the component s suitability for use. 

No single NDT method will work for all flaw detection applications. Each method has advantages and disadvantages when compared to each other. There are many types of test but the following six are the most often used. 

Penetrant testing - this method uses a penetrant dye applied to a pre-cleaned surface. The liquid penetrant which has high surface wetting characteristics is pulled into surface 

We begin our detailed discussion of intramolecular H bonds with a summary. Table 5-1, showing in a general way how the two methods of satisfying H bonding ability affect various physical (and a few chemical) properties. Most of these properties have been discussed in Chapters 2-4, where intermolecular bonds were emphasized. In Table 5-1 the comparison for both inter- and intramolecular compounds is with a normal substance, i.e., one with no H bonding, such as a hydrocarbon. 

Notice the large number of properties (at top of Table 5-1) for which normal behavior can be expected in chelates. This tendency is perhaps the most characteristic generality for intramolecular H bonded compounds. However, it is not unanimous for all properties. 

FIGURE 5-1 Some common m/ramolecular H bonds. This page o-chlorophenol ethyl acetoacetatc (enol form) /3-diketones (enol form) salicylaldehyde. Facing page 5,8-dihydroxy-a-napthoquinone chloral hydrate oc-acetylamino acetamide. 

Some examples of IR spectral behavior for other modes of vibration are contained in a paper by Brato2, Hadii, and Rossmy (269). They 

Structural form Most common in ortho cis, periy Most common in meUiy pardy trans.  

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Table 1. Comparison of Properties of a Typical Novolac with Those of a Typical HOST Homopolymer...

Substitution of fluorine for hydrogen in an organic compound has a profound influence on the compound s chemical and physical properties. Several factors that are characteristic of fluorine and that underHe the observed effects are the large electronegativity of fluorine, its small size, the low degree of polarizabiHty of the carbon—fluorine bond and the weak intermolecular forces. These effects are illustrated by the comparisons of properties of fluorocarbons to chlorocarbons and hydrocarbons in Tables 1 and 2. 

Ton-exchange resins are used repeatedly in a cyclic manner over many years, and deterioration of both physical and chemical properties can be anticipated. Comparison of the properties of used resin with those of new resin is helpfiil to learning more about the nature and cause of deterioration (12). Corrective action frequendy extends the life of the resin. Comparison of properties must always be made with the resin in the same ionic form. 

Table 2. Comparison of Properties of Gases, Supercritical Fluids, and Liquids...

A Sail, TL Blundell. Definition of general topological equivalence m protein structures A procedure involving comparison of properties and relationships through simulated annealing and dynamic programming. J Mol Biol 212 403-428, 1990. 

Table 15.3 Comparison of properties of some rubber-modified polymers with polyimethyl methacrylate)...

Table 21.1 Comparison of properties of unfilled grades of thermoplastics containing p-phenylene groups...

Table 27.2 Comparison of properties of polyurethane, nitrile and natural rubbers...

It is outside the scope of this Chapter to undertake a comprehensive review of 3.stnicture-proper relationships for the different fpims of carbon. P jex >a limited comparison of properties is useful for illustrating the influence of... 

Table 4 Comparison of Properties of LLDPEs Produced by Metallocene Catalyst and Conventional Ziegler-Natta Catalyst...

Ziegler-Natta catalyst. A comparison of properties of resins and their extruded film samples are given in Table 5. 

Table 5 Comparison of Properties of Lactide Polymers with Polystyrene and Poly(vinyl chloride) ...

Ionic bonds may be fully as strong as covalent bonds, so that properties such as hardness, solubility, melting point, ionization in solution, and chemical character are not especially valuable criteria as a rule. Sometimes comparison of properties with those of compounds of known bond type permits reasonably certain conclusions to be drawn. Thus the similarity in physical properties as well as in atomic arrangement of SiC, AIN, and diamond suggests that all three substances contain covalent bonds. PbS is like FeS2, MoS2, etc. in properties rather than like CaS, so that it is improbable that PbS is an ionic substance. 

Comparison of Properties of Dielectric Elastomers with Other Electroactive Materials... 

Comparison of Properties of Sulfur- and Peroxide-Cured Ethylene-Propylene-Diene Rubber (EPDM)... 

Comparison of Property Change Rates, Oven/Field... 

Myers, C. L., Drake, J. T. Brantley, W. A. (1978). A comparison of properties for zinc phosphate cements mixed on room temperature and frozen slabs. Journal of Prosthetic Dentistry, 40, 409-12. 

TABLE 9.3 COMPARISON OF PROPERTIES OF DNA POLYMERASES FROM ANIMAL TISSUES. 

Table 6. Comparison of properties of enzymes involved in biodesulfurization...

Tab. 7.2 Comparison of properties for some atoms in intact and assembled PEO. 

Andreeva and coworkers518 improved on the preparation of Au/a-Fe203 by using a deposition-precipitation method. The preparation involved deposition of Au hydroxide with a solution of sodium carbonate at 60 °C and pH = 8.0 on a fresh precipitate of iron hydroxide. The precipitate was aged for 1 hour at 60 °C, filtered, washed, dried under vacuum at 80 °C, and calcined in air at 400 °C for 2 hours. A comparison of properties and activities is provided in Table 122. The iron oxide crystallites were about 10 nm in both samples investigated. 

C. May and J. Striimpfel, ITO coating by reactive magnetron sputtering — comparison of properties from DC and MF processing, Thin Solid Films, 351 48-52, 1999. 

Table 18.3. Comparison of Properties between Polyimide and Selected Inorganic...

Figure 1.18 Comparison of properties for (I) linear and (IV) dendritic architecture...

The results show the effect of inserting typical a-amino acid residues between a long alkyl group and a POE chain, based on a comparison of properties with those of the usual type of nonionic. 

Table 10. Comparison of Properties of Different Separators Used in Lead-Acid Batteries...

Comparison of Properties of Polyethylene (PE) Using Solid (ZNC) and Soluble Catalysts... 

Table 6 Comparison of properties of blown films (30 pm) PE-LD, Ecoflex , compounds of granular starch and Ecoflex , compounds of thermoplastic starch and Ecoflex ...

Krueger, R. J., and Siegel, L. M. (1982). Spinach siroheme enzymes Isolation and characterization of ferredoxin-sulfite reductase and comparison of properties with ferre-doxin-nitrite reductase. Biochemistry 21, 2892-2904. 

A comparison of properties of BNCP with the reported data of conventional explosives, that is, LA, LS and MF indicates that BNCP is superior to conventional primary explosives in the following respects ... 

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