Related materials

This section summarizes the properties of materials similar to PS but not formed by anodization of a bulk silicon electrode. These materials fall into the following categories  

PS formed chemically without an applied potential in a mixture of HF and an oxidizing agent. 

Porous layers formed anodically on other semiconductors than silicon. 

Luminescent silicon microstructures formed by other methods than anodization and stain etching. 

PS formed chemically without an applied potential in a mixture of HF and an oxidizing agent, e.g. HN03, is called a stain film. The similar nature of electrochemi-cally formed micro PS and stain films was pointed out in 1960 [Arl]. Stain films are usually microporous. They are of predominantly monocrystalline character and show visible PL [Scl6, Jil], If metal films are present on the silicon surface, mesopore formation may also be observed [LilO]. 

Selective Oxidation with Hydrogen Peroxide by TS-1 and Related Materials 

A very successful approach is the use of oxygen donors, closed shell molecules XO able to react with an organic substrate S transferring an oxygen atom to it and affording the desired oxidized product SO and the co-product X arising from the reduction of XO (Reaction 15.1)  

For these reasons, hydrogen peroxide has been, and still is, an attractive reagent for selective oxidations on both the laboratory and industrial scale. 

The availability of an industrial process for producing TS-1 allowed the development of several selective oxidations, all using hydrogen peroxide as a versatile and environmentally friendly oxidizing agent which gives water as the only co-product. The epoxidation of propene (Hyprox process), the phenol hydroxylation and the ammoximation of cyclohexanone are now H202-based industrial processes benzene hydroxylation to phenol is currently under advanced evaluation. 

Propene oxide is particularly important, since it is a basic intermediate with a production capacity of around 7 10 t/y. Its classical industrial production route is 

HUP and many other natural or synthetic compounds belong to the torbernite mineral group of general formula M, y(U02X04)(H30)y. 3H2O where X is P or As and M is a cation such as K, NH4 , Na, Li, Ca, Pb, Ag or AP. The role of interlayer cations and water molecules in torbernite is similar to that in zeolites, clay minerals, some feldspars and micas, jarosites, autunites and clathrate compounds. In all these materials solid solutions between protonic and ionic derivatives are readily observed ion exchange and protonic conductivity can thus be expected. 

Phosphate and arsenate groups can be substituted by silicate or vanadate groups as in uranophane, for instance . This compound, represented by Ca(H30)(U02Si04)2.3H20 , is one of the earliest known uranium minerals and is found in the form of yellow to yellow-orange fibres. Its structure, similar to that of HUP, consists of U02Si04 

Minerals of alunite-jarosite groups have the general formula MAsCSOJjCOH) where M is H3O+, NH4+, Na+, K+, Rb+, Ag+, T1+, O.SPb and A is AP (alunite) or Fe (jarosite). Related synthetic materials MFe(S04)2(0H)6 (M = H3O+, NH4+), MGa3(S04)2(0H)6 also form solid solutions Hydronium alunite can be prepared by hydrothermal reaction from Al2(S04)3.16H2O at 250 °C while only the mixed derivative is obtained by refluxing at 105 °C. Sulphate 

The room temperature conductivity of hydrated pellets of hydronium alunite, H30Al3(S04)2(0H)6 is about 3 x 10 Q cm and that of dry pellets much lower, 10 fl cm , which indicates a major contribution of the surface conductivity similar to that in aZr(HP04)2. nH20 and in zeolites. The presence of OH groups may favour the building up of a conducting water layer. 

Sugitami, H. Kauga, K. Nagashima and S. Fujiwara, Nippon. Kogoku Zashi 90 (1969) 52-6. 

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Phenohc intermolecular coupling (46) of two laudanosoline (77, R = H) fragments, which may be preceded or followed by partial O- or N-methylation, gives rise to the dimeric or bisben2yhsoquinoline alkaloids such as oxyacanthine (79), obtained along with related materials from the roots... 

M. E. Lines and A. M. Glass, Principles and Applications ofFerroelectrics and Related Materials, Clarendon, Oxford, UK, 1977. 

The antagonisms that exist between unsaturated fatty acids, and carotene and vitamin E are compHcated and largely undefined. Linoleic acid acts as an antivitamin to i7/-a-tocopherol [59-02-9, 1406-18-9, 10191-41-0] (vitamin E) by reducing availabiHty through direct intestinal destmction. Various Hpoxidases destroy carotenes and vitamin A (73). Dicoumarol [66-76-2] (3,3 -methylenebis(4-hydroxycoumarin)) is a tme antimetaboHte of vitamin K [12001 -79-5] but seems to occur only in clover and related materials that are used primarily as animal feeds (74). 

Suggested Methodsfor Analysis of Metals, Ores, and Related Material, 9th ed., E-2 Sm 8—25, American Society for Testing and Materials, Philadelphia, 1992. 

M. Takahashi, in L. Rebenfeld, ed., Sdence andTechnologj of Fibers and Related Materials, Wiley-Interscience, New York, 1991, p. 38. 

A fuU listing of aU U.S. patents issued between Febmary 1970 through Febmary 1981 is given in Reference 26. Similar related material on membranes, ultrafiltration, and reverse osmosis can be found in References 46—49. 

Nd2Fe B Family of Magnets and Related Materials. The high cost of cobalt and samarium stimulated investigation and development... 

The American Society for Testing and Materials (ASTM) 1916 Race Street Philadelphia, Pa. 19103 The ASTM MnnualBook ofMSTM Standards contains all up-to-date formally approved (ca 9000) ASTM standard specifications, test methods, classifications, definitions, practices, and related materials, eg, proposals. These are arranged in 15 sections plus an index volume as follows. 

Some commercially available molecular-sieve products and related materials are shown in Table 6, classified according to the basic 2eohte stmcture types. In most cases, the water content of the commercial product is below 1.5—2.5 wt % certain products, however, are sold as fully hydrated crystalline powders. 

There is extensive Hterature on PC blends with ABS, and blends of PC with related materials such as SAN, methacrylate-butadiene—styrene (MBS) emulsion-made core-shell mbber modifiers (297—299), and other impact modifiers. One report reviews some of these approaches and compares PC blends based on emulsion vs bulk ABS (229). In PC—ABS blends, no additional compatihili er is used, because of the near-miscihility of the SAN matrix of ABS and PC. 

Doping of the siHcon can have a large effect on the etch rate, and layers of different materials such as Si02 and Si N can have different etch rates. Eor pressure sensors, thin diaphragms of Si or related materials are etched into the wafer (see Pressure measurements). 

Stevioside and rebaudioside A are diterpene glycosides. The sweetness is tainted with a bitter and undesirable aftertaste. The time—intensity profile is characteristic of naturally occurring sweeteners slow onset but lingering. The aglycone moiety, steviol [471 -80-7] (10), which is the principal metaboHte, has been reported to be mutagenic (79). Wide use of stevia ia Japan for over 20 years did not produce any known deleterious side effects. However, because no food additive petition has been presented to the FDA, stevioside and related materials caimot be used ia the United States. An import alert against stevia was issued by the FDA ia 1991. In 1995, however, the FDA revised this import alert to allow the importation and use of stevia as a diet supplement (80), but not as a sweetener or an ingredient for foods. Several comprehensive reviews of stevia are available (81,82). 

In addition to FR treatments that are durable to laundering and weathering, work has also been done on a variety of treatments for the production of FR fabrics using inorganic salt mixtures. These treatments have usually been used on drapes and related materials that are not exposed to laundering or washing. 

Demountable joints are commercially available in great variety in stainless steel, but less so in aluminum alloy or related materials. Experimental joints have been made in which aluminum flanges employ aluminum foil as gasket material. 

More recendy, asphalts have been defined as the manufactured materials that are produced during petroleum processing whereas bitumens have been defined as the naturally occurring materials (5,6). That is, petroleum and related materials can be divided into various class subgroups ... 

The fluorite stmcture, which has a large crystal lattice energy, is adopted by Ce02 preferentially stahi1i2ing this oxide of the tetravalent cation rather than Ce202. Compounds of cerium(IV) other than the oxide, ceric fluoride [10060-10-3] CeF, and related materials, although less stable can be prepared. For example ceric sulfate [13590-82-4] Ce(S0 2> certain double salts are known. 

Linear transport velocity of the material is almost proportional to the product of frequency and stroke for these conveyors. However, the transport velocity and the depth that can be obtained with a specific material is dependent on the handling characteristics of that material. Manufacturers have accumulated data banks relating material characteristics to attainable conveying velocities for their proprietary conveyor designs. 

Owing to the original determination from uv—vis spectral solvatochromic shifts, 7T, B, and are called solvatochromic parameters. General rules for estimation of these variables have been proposed (258). Examples of individual parameter investigations are available (260,261). As previously mentioned, individual LEER—LSER studies are performed on related materials. A common method to link these individual studies to group contribution methods, and thereby expand the appHcabiUty, is by expansion of solvatochromic parameters to log—linear relationships, such as... 

M. Mandels and E.T. Reese, in Advances in Enzymic Hydrolysis of Celltdose and Related Materials, ed. E. T. Reese, Pergamon, Oxford, 1963, pp. 115-157. 

It is a good practice to ensure that both the toller and client have records of the complete incident and accident history for the toll. This information can be vital to the industry as a database of experience with the tolled process. Process safety concerns for future tolls of the product or related materials can benefit from this practice. 

Further reading Kroto, Fischer and Cox Fullerenes Pergamon Press, Oxford 1993 ISBN 0080421520 Kadish and Ruoff (Eds) Fullerenes Recent Advances in the Chemistry and Physics of Fullerenes and Related Materials The Electrochemical Soc. Inc, Pennington, NJ, 1994 ISBN 1566770823]... 

The above paragraphs indicate some of the major uses of plastics materials, but these materials also find applications in a variety of other areas. In addition, closely related materials such as rubbers, fibres, surface coatings and adhesives are of considerable importance. 

As indicated by the title, these processes are largely due to the work of Ziegler and coworkers. The type of polymerisation involved is sometimes referred to as co-ordination polymerisation since the mechanism involves a catalyst-monomer co-ordination complex or some other directing force that controls the way in which the monomer approaches the growing chain. The co-ordination catalysts are generally formed by the interaction of the alkyls of Groups I-III metals with halides and other derivatives of transition metals in Groups IV-VIII of the Periodic Table. In a typical process the catalyst is prepared from titanium tetrachloride and aluminium triethyl or some related material. 

The viscosity of PVC pastes may be reduced in many instances by the presence of certain polyethylene glycol derivatives and related materials. Because of their tendency to exude, the use of these viscosity depressants should be restricted to levels of less than 1% of the total mix. 

In the mid-1980s Hoechst introduced a related material, Hostaflon TFB, a terpolymer of tetrafluoroethylene, hexafluoropropene and vinylidene fluoride. 

In addition to the various vinyl polymers diseussed in the preceding seven chapters a large number of other polymers of this type have been described in the literature. Some of these have achieved commercial significance and those which have interest as plastics or closely related materials are the subject of this chapter. 

Polyimides and related materials have also been used in a number of specialist applications. Polyimide foams (Skybond by Monsanto) have been used for the sound deadening of jet engines. Polyimide fibres have been produced by Rhone-Poulenc (Kermel) and by Upjohn. 

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