Forward compatibility

There are many versions of Matlab and of Windows and for the more elaborate interfaces between die two packages it is necessary to refer to technical manuals. We will illustrate diis section with Matlab version 5.3, although many readers may have access to more up-to-date editions. All are forward compatible. There is a good on-line help facility in Matlab type help followed by die command, or follow the appropriate menu item. However, it is useful first to have a grasp of the basics which will be described below. 

The second major contribution of PRISM is support for database versioning with backward and forward compatibility. When starting with version N of a database, if one uses SMOs to create version N + 1 of the database, PRISM will provide at least one of the following services to applications whenever the SMOs are deemed to be invertible or the user provides a manual workaround ... 

Of course, when you install a macro, you might also want to verily that it performs its task properly. Typically, when you write a macro yourself, count on spending at least as much time debugging it as you have already spent on writing the macro in the first place, unless you have verified every step as you went along. Ready-made macros from, say, a diskette or from an Internet source should not give you such problems, but that may not always be the case. For example, you may encounter difficulties when trying to run an Excel 97 macro in Excel 5, since software is seldom forward-compatible. 

It likely that you are using different versions of Synopsys tools. In other words, the db file was generated by a more recent version of DC while you are trying to read the db file now into a previous version of DC. In short, db files are backward compatible but not forward compatible. To check the version of DC, use the following command ... 

Work on this book has sparmed several software releases of Synopsys tools. Small changes in commands in different versions are likely, but forward compatability can be assured in most cases. At the end of each chapter a Recommended Reading list has been provided to help the reader access the appropriate Synopsys documentation, if required. Finally, the Appendix provides sample dc shell scripts and a brief introduction on Synopsys On-line Documentation (iview). These scripts have been made as general purpose as possible. If you have mastered the material in the above chapters, writing scripts from scratch should be as simple as modifying these scripts to suit your needs ... 

A number of lead-free component termination finishes have been evaluated (Ref 13, 55) and used over the years. For passive components (such as chip capacitors and resistors), matte Sn plating has been used for many years with the tin-lead solder, and can be used with lead-free solder as well. For leaded components (e.g., quad flat pack or QFP), plating of matte tin or tin alloys may be used with lead-free solders (forward compatible). The tin whisker concern will be discussed in a later section. Nickel-lead has been used with the tin-lead solder for many years, and Ni-Pd-Au is currently an alternative for leaded components for lead-free soldering Ni-Pd typically does not provide as good wett-ahifity as tin. Area array packages with SAC halls are available and work well with the SAC solder. 

Assuming that the components can meet the temperature requirements as discussed above, tin and Ni-Pd-Au platings are generally considered to be forward compatible with lead-free solder, as well as backward compatible with the tin-lead solder. This makes it much easier to manage production lines with the tin-lead solder and lead-free solder in co-existence within the same factory during the transition to lead-free. 

Area Array Assemblies with Sn-Pb Balls and SAC or Sn-Pb Paste. Another scenario of interest during the transition to lead-free technology is that of conventional area-array components using Sn-Pb balls assembled with SAC paste. This scenario is often described as a forward compatibility situation. In Fig. 11, we show cycles-to-1% failure for Sn-Pb ball area array components assembled with SAC paste versus cycles-to-1% failure for similar components assembled with Sn-Pb paste. The data was gathered from relevant test cells in several independent studies (Ref 3,11,12, 22, 29, 32, 33). Figure 11(a) shows the data for assemblies that were cycled between — 40 and 125 °C (— 40 and 257 °F) (6 data points). Figure 11(b) shows similar test data for thermal cycling under milder conditions 0 to 100 °C (32 to 212 °F) (7 data points) and 15 to 95 °C (59 to 203 °F) (2 data points for 144 Input/Output PEG As assemblies with Ni-Au or Sn-Cu HASL board finish). 

Forward-compatibility test results are also mixed with a strong effect of thermal cycling conditions on cyclic life trends. Under conditions of 0 to 100 °C (32 to 212 °F), or even milder, area-array assemblies using Sn-Pb balls and SAC paste appear less reliable than conventional Sn-Pb area-array assemblies. 

The net effect is that tackifiers raise the 7g of the blend, but because they are very low molecular weight, their only contribution to the modulus is to dilute the elastic network, thereby reducing the modulus. It is worth noting that if the rheological modifier had a 7g less than the elastomer (as for example, an added compatible oil), the blend would be plasticized, i.e. while the modulus would be reduced due to network dilution, the T also would be reduced and a PSA would not result. This general effect of tackification of an elastomer is shown in the modulus-temperature plot in Fig. 4, after the manner of Class and Chu. Chu [10] points out that the first step in formulating a PSA would be to use Eqs. 1 and 2 to formulate to a 7g/modulus window that approximates the desired PSA characteristics. Windows of 7g/modulus for a variety of PSA applications have been put forward by Carper [35]. 

Although the ester mechanism is not yet generally accepted, the evidence accumulating since it was first put forward is in its favour, and the evidence which is alleged to be against it, or which has been interpreted in terms of ion-pairs in place of the ester, is certainly compatible with the ester theory [13, 14,15]. We note in passing an interesting application of the polymerisation of styrene by perchloric acid it was used as an indicator-reaction in the enthalpy titration of weak bases [16]. 

Mode-of-Action Hypotheses. May we now turn to consider some of the suggested mechanisms put forward to explain the hypotensive action of the 3-blocking drugs and see if any are compatible with the clinical and pharmacological data. Before doing so however, it perhaps would be useful to summarise the characteristics of the anti-hypertensive action of the drugs. 

Marcus and Rice6 made a more detailed analysis of the recombination from the point of view of the reverse reaction, the unimolecular decomposition of ethane, C2Ha - 2CH3. By the principle of microscopic reversibility the transition states must be the same for forward and reverse paths. Although they reached no definite conclusion they pointed out that a very efficient recombination of CH3 radicals would imply a very high Arrhenius A factor for the unimolecular rate constant of the C2H6 decomposition which in turn would be compatible only with a very "loose transition state. Conversely, a very low recombination efficiency would imply a very tight structure for the transition state and a low A factor for the unimolecular decomposition. 

The conditions required for a non-symmetric Universe were first put forward by Sakharov [16] they include non-conservation of the baryon number, C and CP symmetry violation, and the existence of a period of thermal non-equilibrium during the evolution however, the present limits on the proton lifetime (1033 years) are inconsistent with the first condition, and the small degree of CP symmetry violation displayed by kaons is not compatible with the second condition. 

Backwards compatible multichannel coding adds the option of forward and backwards compatible coding of multichannel signals including the 5.1 channel configuration known from cinema sound. 

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