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Miller rule

Main-chain scission has been shown to occur in polyphenylvinylketone under UV irradiation (366 nm). Norrish type-2 scission due to reaction of the first n-II triplet state of the ketone has been shown to occur [422]. Under 7-irradiation, this polymer, which was expected to crosslink according to the Miller rule, was shown to undergo main-chain fracture with a G value of 0.35. Inhibition of the degradation in the presence of napthalene and diphenyldisulphide demonstrates the participation of radicals and excited n-II triplet states in the radiolysis [423]. [Pg.290]

It is seen that for high peak power applications a low refractive index is required. In the crystal case, to avoid SHG (second-harmonic generation), a centro-symmetric structure has to be searched for, because the so-called Miller rule (Miller 1964) gives for the allowed elements of a nonlinear susceptibility tensor for second-harmonic generation. [Pg.579]

Miller et al. [9] hypothesized rules on the regioselectivity of addition from the study of the base-catalyzed addition of alcohols to chlorotnfluoroethylene. Attack occurs at the vinylic carbon with most fluorines. Thus, isomers of dichloro-hexafl uorobutene react with methanol and phenol to give the corresponding saturated and vinylic ethers The nucleophiles exclusively attack position 3 of 1,1-dichloro-l,2,3,4,4,4-hexafluoro-2-butene and position I of 4,4-dichloro-l,l,2,3,3,4-hexafluoro-1-butene [10]. In I, l-dichloro-2,3,3,4,4,4-hexafluoro-l-butene, attack on position 2 is favored [J/] (equation 5) Terminal fluoroolefms are almost invariably attacked at tbe difluoromethylene group, as illustrated by the reaction of sodium methoxide with perfluoro-1-heptene in methanol [/2J (equation 6). [Pg.730]

From the Larson-Miller analysis, it is possible to derive more easily interpreted information relating to the effects of sustained high temperature on the life of a tube. A common rule of thumb is that a tube wall temperature increase of 20°C will shorten a tube life by over 50% from its design period of 10 years to less than 5 years. The cost of a typical reformer tube is USD 6000-7000. With typical reformer sizes in the order of 300-400 tubes and taking on-site expenditure into account, this puts the cost of a complete re-tube in the range... [Pg.366]

Unlike the case of diffraction of light by a ruled grating, the diffraction of x-rays by a crystalline solid leads to the observation that constructive interference (i.e., reflection) occurs only at the critical Bragg angles. When reflection does occur, it is stated that the plane in question is reflecting in the nth order, or that one observes nth order diffraction for that particular crystal plane. Therefore, one will observe an x-ray scattering response for every plane defined by a unique Miller index of (h k l). [Pg.191]

D-glucose and its lactone from 2,3,6-trimethyl-D-glucose provided conclusive proof that the ring system was not of the hexylene oxide type.142 188 The final evidence necessary to characterize the tetramethylglucose in question as a furanose derivative was provided by Haworth, Hirst and Miller,176 who demonstrated that oxidation of the tetramethylglucose with bromine water and of the resulting lactone with nitric acid yielded dimethoxysuccinic acid and oxalic acid, but not i-zyZo-trimethoxyglutaric acid, the absence of which ruled out a pyranose structure. [Pg.203]

Mismatch Repair. Mispairs that break the normal base-pairing rules can arise spontaneously due to DNA biosynthetic errors, events associated with genetic recombination and the deamination of methylated cytosine (Modrich, 1987). With the latter, when cytosine deaminates to uracil, an endonuclease enzyme, /V-uracil-DNA glycosylase (Lindahl, 1979), excises the uracil residue before it can pair with adenine at the next replication. However, 5-methyl cytosine deaminates to form thymine and will not be excised by a glycosylase. As a result, thymine exits on one strand paired with guanine on the sister strand, that is, a mismatch. This will result in a spontaneous point mutation if left unrepaired. For this reason, methylated cytosines form spontaneous mutation hot-spots (Miller, 1985). The cell is able to repair mismatches by being able to distinguish between the DNA strand that exists before replication and a newly synthesized strand. [Pg.182]

Figure 4.26. Optimum values, in accordance with Wade s rules and as summarized by Miller et al. (2002), of the valence electron concentration VEC (total number of electrons divided by the cluster atom number) as a function of the number of cluster atoms for closo and nido deltahedra. On the left the values computed for the main group elements and on the right those relevant to the transition metals. Figure 4.26. Optimum values, in accordance with Wade s rules and as summarized by Miller et al. (2002), of the valence electron concentration VEC (total number of electrons divided by the cluster atom number) as a function of the number of cluster atoms for closo and nido deltahedra. On the left the values computed for the main group elements and on the right those relevant to the transition metals.
The electroreductive cyclization reaction of 6-heptene-2-one 166, producing CIS-1,2-dimethylcyclopentanol 169, was discovered more than twenty years ago [166]. In agreement with Baldwin s rules, the 5-exo product is obtained in a good yield. Since that time, the mechanism of this remarkable regio- and stereoselective reaction has been elucidated by Kariv-Miller et al. [167-169]. Reversible cyclization of the initially formed ketyl radical anion 167 provides either the cis or the trans distonic radical anion. Subsequent electron transfer and protonation from the kinetically preferred 168 leads to the major cis product 169. The thermodynamically preferred 170 is considered as a source of the trace amounts of the trans by-product 171 (Scheme 32). [Pg.101]

The interest in efficient optical frequency doubling has stimulated a search for new nonlinear materials. Kurtz 316) has reported a systematic approach for finding nonlinear crystalline solids, based on the use of the anharmonic oscillator model in conjunction with Miller s rule to estimate the SHG and electro optic coefficients of a material. This empirical rule states that the ratio of the nonlinear optical susceptibility to the product of the linear susceptibilities is a parameter which is nearly constant for a wide variety of inorganic solids. Using this empirical fact, one can arrive at an expression for the nonlinear coefficients that involves only the linear susceptibilities and known material constants. [Pg.59]

A lower court ordered Miller and Layton freed, ruling that the Second Amendment prevented Congress from regulating commerce in weapons. The two bootleggers promptly disappeared into the countryside. But... [Pg.17]

Sales TRM (1998) Smallest focal spot. Phys Rev Lett 81 3844-3847 Friedman E, Miller JL (2003) Photonics rules of thumb optics, elctro-optics, fiber optics and lasers. SPIE McGraw-Hill, New York... [Pg.204]

He also learned how to acquire supplies in strange ports "When I went ashore I usually go to drink and hang out with a bunch of fellows along the dock. There are a lot of dope fiends hanging around a water-front." Despite his carousing, Miller also knew how to respect the rules of shipboard life ... [Pg.292]

In 1972, Miller made a detailed analysis of the data on the influence of electron acceptor additives on the yield of ionic products during radiolysis of organic matrices and showed this to agree quantitatively with the electron tunneling mechanism of the formation and annihilation of these particles [7], In particular, the annihilation of et) in MTHF glass containing naphthalene (Nh) as the additive was found to be accompanied by simultaneous formation of the Nh anion radical (via the reaction etj. + Nh - Nh ). The kinetic curves for this reaction at 77 and 87 K coincided, which ruled out the possibility of the reaction rate being determined by thermal diffusion. [Pg.4]

A 3D crystal has its atoms arranged such that many different planes can be drawn through them. It is convenient to be able to describe these planes in a systematic way and Fig. 4 shows how this is done. It illustrates a 2D example, but the same principle applies to the third dimension. The crystal lattice can be defined in terms of vectors a and b, which have a defined length and angle between them (it is c in the third dimension). The box defined by a and b (and c for 3D) is known as the unit cell. The dashed lines in Fig. 4A show one set of lines that can be drawn through the 2D lattice (they would be planes in 3D). It can be seen that these lines chop a into 1 piece and b into 1 piece, so these are called the 11 lines. The lines in B, however, chop a into 2 pieces, but still chop b into 1 piece, so these are the 21 lines. If the lines are parallel to an axis as in C, then they do not chop that axis into any pieces so, in C, the lines chopping a into 1 piece and which are parallel to b are the 10 lines. This is a simple rule. The numbers that are generated are known as the Miller indices of the plane. Note that if the structure in Fig. 6.4 was a 3D crystal viewed down the c axis, the lines would be planes. In these cases, the third Miller index would be zero (i.e., the planes would be the 110 planes in A, the 210 planes in B, and the 100... [Pg.201]

T. M. Miller, T. X. Neenan, Chem Mater. 1990, 2, 346-349. T. M. Miller, T. X. Neenan, R. Zayas, H. E. Bair, /. Am. Chem. Soc. 1992, 334, 1018-1025. We use the family name polybenzene dendrimers (generally polyarene dendrimers) instead of polyphenylene dendrimers because the rules of nomenclature restrict pheny-lene to -QHg-. [Pg.139]

The rules for determining Miller-Bravais planar indices are similar to those for Miller indices with three axes. [Pg.21]


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