Parallel case

Figure 4-11. INDQ/SCI-caleulalcd evolution of the transition energies (upper pan) and related intensities (bottom pan) of the lowest two optical transitions of a cofacial dimer formed by two stilbenc molecules separated by 4 A as a function of the dihedral angle between the long molecular axes, when rotating one molecule around the stacking axis and keeping the molecular planes parallel (case IV of Figure 4-10). Open squares (dosed circles) correspond to the S(J - S2 (S0 — S, > transition.

The nitro form is much more stable than the aci form in sharp contrast to the parallel case of nitroso-oxime tautomerism, undoubtedly because the nitro form has resonance not found in the nitroso case. Aci forms of nitro compounds are also called nitronic acids and azinic acids. 

The examples cited above are only two of the many possible cases of H-bond isomerization. Because of the low kinetic barriers separating these species, equilibration of H-bonded isomer populations to limiting thermodynamic values is generally expected to be much faster than for covalent isomers. Methods of quantum statistical thermodynamics can be used to calculate partition functions and equilibrium population distributions for H-bonded isomers,41 just as in the parallel case for covalent isomers and conformers. 

According to Stettbacher, mercuric azide develops the same vol of gas on deton as MF but it is 20 times more brisant. Wohler Krupko (Ref 3) observed that its sensitivity depended on the cryst size of the azide. Mercuric azide is considered to be more sensitive to impact and friction than MF and is so unstable that it frequently undergoes spontaneous deton at the slightest touch even under w (Refs 5 7). Hitch (Ref 4) noted this sensitivity expecially when the azide was prepd from mercuric nitrate and Na or K azide solns but by careful thermal studies he decompd it quanty into its elements without expln below 300°. Miles (Ref 8) reported that in every case when /3-crysts of Hg(N3)2 were present the material was likely to expl, and in w or more rapidly in mercuric nitrate soln, the /3-type was unstable being transformed to the o-type, as in the parallel case of LA,... 

This recalls the parallel case of the addition of hydrogen halides to the unsaturated hydrocarbons observed by A. P. Eltekoff. As in the case of sulphurous and nitrous acids, the facts can also be explained by assuming the desmotropic change ... 

For example, Ft(s) could be pressure in an acoustic tube and 1 (s) the corresponding volume velocity. In the parallel case, the junction reduces to the unloaded case when the load impedance Rj(s) goes to infinity. 

For the quantitative description of the stiffness of the composite, the Kemer equation of 9.1.5. and 9.2 can again be applied, though in a somewhat modified shape. Since a fibre brings about anisotropy of properties in its environment, we have to consider two different cases, viz. the E-modulus parallel to the fibre, Ep, and the one perpendicular to it, Et. For both cases Kemer s equation holds, in which now A, in the parallel case, Ev, equals 2-l/d, while for Et, A = j. 

The information that all case item values are mutually exclusive needs to be passed to the synthesis tool. This is done by using a synthesis directive called parallel case. When such a directive is attached to a case statement, a synthesis tool interprets the case statement as if all case items are mutually exclusive. Since the synthesis directive appears as a comment in the Verilog HDL model, it has no effect on the language semantics of the model. This implies that no priority logic is synthesized for the case statement control instead decoding logic is used. Here is the case statement with the parallel case directive. 

Figure 2-37 With parallel case directive no priority logic.

A word of caution. The synthesis directive, parallel case, can potentially cause a functional mismatch between the design model and the synthesized netlist Chapter 5 elaborates on this further. 

The two synthesis directives we have seen so far, full case and parallel case, can potentially cause functional mismatches to occur between the design model and the synthesized netlist. The problem is that these directives are recognized only by a synthesis tool and not by a simulation tool. In either of the cases, if the designer is not careful in specifying the directive, mismatches can occur. 

Here is an example of a parallel case synthesis directive. 

Recommendation Use caution when using the synthesis directives full case and parallel case. Use only if really necessary. 

In his search for regularity, Werner noted that cases (1) and (3) occur at or near the end othis fourth and sixth periods, respectively, while cases (2) and (4) occur six or seven places beyond cases (1) and (3), respectively. Since Co precedes Ni in case (2), he assumed that Nd should likewise precede Pr in the corresponding parallel case (4). As further evidence for such an inversion, Werner cited the similarities in color of the salts (Co+ and Nd+, pink Ni+ and Pr+, green). 

Second, a crossover to the n -state was predicted in [31,43,44] for the parallel case even in the absence of order parameter oscillations in thin F layers. 

Methyl-6-methylthio-8-azapurine, refluxed for 2 h with aqueous ammonia, produced a 90% yield of 6-amino-9-methyl-8-azapurine. In parallel cases, ethanolic ammonia was used at 130-150°C. - 7-Methyl- and 8-methyl-2,6-bis(methylthio)-8-azapurine and ethanolic ammonia (130°C, 12 h) gave 6-amino-7- or -8-methyl-2-methylthio-8-azapurine in 90% yield. ... 

Tropine and pseudo-tropine both possess the same structural formula, for, on oxidation, they each 3deld tropinone, whilst the latter, when reduced, gives a mixture of the two hydroxy-bases (Willstatter and Iglauer, Ben, 1900, 33,1170). Willstatter concluded, therefore, that a cis-/rans-isomerism, dependent on the relative positions in space of the hydroxyl and methyl groups, existed between tropine and pseudo-tropine. Objection to this explanation might be made on the ground that no quite parallel case of isomerism seems to have been observed, and it therefore appeared to the present authors that it should not be accepted unreservedly so long as another explanation is possible. 

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