Grooves, number

This intensity distribution is plotted in Fig.4.18 for two different values of the total groove number N. The principal maxima occur for 6 = 2mTr, which is, according to (4.24) equivalent to... 

Scratch Te.st. The scratch microhardness test is a refinement of the Mohs test. The corner of a cubic diamond is drawn across the surface of a metaHographicaHy poHshed sample under a constant load, usuaHy 29.4 N (3 kgf). The width of the resultant Vee groove scratch varies inversely with the hardness of the material displaced where H = scratch hardness number and A = groove width in micrometers. 

For moderate general process requirements at gauge pressures less than 2058 kPa (300 Ibf in ) and less than 177°C (350°F), tube-sheet holes without grooves are standard. For all other sei vices with expanded tubes at least two grooves in each tube hole are common. The number of grooves is sometimes changed to one or three in proportion to tube-sheet thickness. 

Only a rather limited number of base pairs is needed to provide unique and discriminatory recognition sites in the major groove. This is illustrated in Figure 7.8, which gives the color codes for the hexanucleotide recognition sites of three different restriction enzymes—Eco Rl, Bal 1, and Sma 1. It is clear that these patterns are quite different, and each can be uniquely recognized by specific protein-DNA interactions. 

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