Shielding fraction

The shielding fraction is a comparison between the measured volume susceptibility and -1/4, and it is given simply by -4 xv... 

Figure 6 shows the exclusion/expulsion ratio versus applied field using the data from Figure 5. The inset to Figure 6 emphasizes the behavior at low fields as the measurement field is reduced below 10 Oe, the exclusion/expulsion ratio decreases smoothly to unity. This confirms that the entire crystal is superconducting, since the shielding fraction for this crystal is approximately 0.97 from the linear portion of the shielding M-H curve. There is a decided advantage to plotting the exclu-...

Single-phase KjCgo and Rb Qo materials were prepared by reaction of aUcali-metal alloy or alkali-metal with 60 as described in detail elsewhere (3, 4). Briefly, a 3 1 mixture of MHg or M (M = K, Rb) and C o were sealed under vacuum in a quartz tube and then heated at 200°C. When the shielding fraction of superconducting phase... 

K3C50 and RbgC samples used in this study are shown in Fig. 1. The transition temperatures of these K- and Rb-doped materials are 19 and 29 K, respectively, and the low temperature shielding fractions are approximately 100% for both samples. 

Fig. 1. Temperature (T) dependence of the magnetization obtained for a 4.1-mg K3 Cjo sintered pellet (open circles) and a 3.8-mg Rbj C o sintered pellet (filled circles). The T s of the K3C60 and Rb3Cfto samples are 19.0 and 28.6 K, respectively. The curves were recorded by cooling in zero field to 5 K and subsequent warming in a lO-Oe field. The shielding fractions estimated from these curves are approximately 100%.

Gly-Val-Gly-Val-OMe, where the valine in position 4 gives a solvent-shielded fraction of 0.76, whereas the valine carbonyl carbon in position 1 has a solvent-shielded fraction of 0.85. Thus, solvent shifts are potentially useful in pairing solvent-shielded C=0 and N-H groups (Urry, 1974a,b). 

Experiment 6. Fractional Distillation of a Mixture of Benzene and Toluene. Fractionally distil about 40 ml. of a mixture of equal volumes of benzene and toluene, using the type of fractionating column shown in Fig. ii(b), in which about 18-20 cm. of the column are actually filled with glass sections, but in which the cotton-wool lagging is not used. Distil very slowlyy so that the total distillation occupies about hours. Shield the apparatus very carefully from draughts. Collect the fractions having the b.ps (a) 80-85°, ( ) 85-107°, (c) 107-111°. A sharp separation should be obtained, e.g.y these fractions should have volumes of about 19, 2, and 17 ml. respectively. 

Vanadyl trichloride (VOCI3) [7727-18-6] M 173.3, m-79.5°, b 124.5-125.5°/744mm, 127.16°/760mm, d 1.854, d 1.811. Should be lemon yellow in colour. If red it may contain VCI4 and CI2. Fractionally distil and then redistil over metallic Na but be careful to leave some residue because the residue can become EXPLOSIVE in the presence of the metal USE A SAFETY SHIELD and avoid contact with moisture. It readily hydrolyses to vanadic acid and HCl. Store in a tightly closed container or in sealed ampoules under N2. [Inorg Synth 1 106 1939, 4 80 1953.]... 

Both u.v. radiation and electron beam curing are best suited to flat or nearly flat objects, because the beams are directional and shielding must be avoided. Electron beam curing also requires the coating to be in an oxygen-free gaseous atmosphere. Both techniques cure in a fraction of a second and are suitable for fast, high-volume production lines. 

The deuterium isotope effects on chemical shift consists of intrinsic isotope effect (direct perturbation of the shielding of X atom) and equilibrium isotope effect (perturbation of the equilibrium caused by the isotopic substitution). The values of deuterium isotope effects are to some extent independent of chemical shifts and allow determination of the mole fraction of the forms in equilibrium. 

All the described properties of such a s-fraction of poly(NVCl-co-NVIAz) synthesized at the temperature above the PST of the reacting system allowed us to draw the conclusion that the chains of this type had the comonomer sequence, which at the temperatures above the conformation transition facilitated the formation of polymer particles, where H-blocks are in the interior shielded by the P-blocks against additional intermolecular association. Such a behaviour of this copolymer in aqueous media is close to that of oligomeric proteins similar to casein [46] possessing a rather hydrophobic core surrounded by the polar segments. 

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