Matrix defects

In order to account for the real 3D structure of cylindrical microdomains, we denote the configurations in Fig. 22a, e and c, g as cylinder-phase defects (cyl-dislocation and +1/2 cyl-disclination), and the configurations in Fig. 22b,f and d,h as matrix defects (m-dislocation and m-disclination). In our systems, cyl-dislocations generally develop during the early stages of film annealing when the overall defect density is high. In well-equilibrated films, cyl-dislocations are less frequent as compared to m-dislocations. 

If the family of the vectors s does not provide this subspace, i.e. the family rank is lower than the matrix defect... 

The public domain library solver LSODA (Hindmarsh 1984) has been used to integrate directly the master equation (Gokhman and Bergner 2010) for the study of the matrix defect subsystem containing free vacancies, spherical VC with sizes up to 1000 vacancies, free SIA, and planar SIA... 

PA studies on RPV steels are important because they have the potential to provide information on matrix defects. However, since interpretation of the data from complex commercial steels is difficult, many studies have focused on model alloys. In Section 9.11.1 we include a brief review of a selection of PA data from the literature, focusing first on model alloys and then on steels. It is shown that, in combination with post-irradiation annealing and other microstructural techniques, positron annihilation techniques can help elucidate the nature of the positron traps. 

APT (indirect) APT cannot identify the presence of interstitials or vacancies, but careful studies of the non-random distribution of solute atoms prior to the formation of solute clusters provide insight into the association of solute with small matrix defects. 

Data from single-variable mechanical property studies have characterised the matrix defect term as being due to two components stable matrix... 

In alloys and RPV steels with > 0.07wt%Cu, and irradiation temperatures > 200°C, Cu-enriched solute clusters form. At irradiation temperatures > 325 °C, these can grow to >4nm diameter, and probably transform to the equilibrium fee -Cu phase, but at the temperatures and fluence of interest most CECs in irradiated steels will be bcc." Radiation-induced point defects enhance the substitutional solute diffusion rate and enhance the rate of precipitation. In addition, nucleation of CECs appears to be easier in the presence of matrix defects. The nature of the matrix defects on which CECs nucleate is not clearThe relative importance of homogeneous and heterogeneous nucleation of CECs under irradiation is not agreed, although homogeneous nucleation will, naturally, become more likely as the Cu supersaturation increases. ... 

R.G. Carter, T. Onchi, N. Soneda, K. Dohi, J.M. Hyde, C.A. English, M.T Hutchings, W. Server, J.E. Coste and J.C. Van Duysen. Thermal stability of matrix defects in irradiated pressure vessel steels , Proc. Eontevraud IV Contributions of Materials Investigation to the Resolution of Problems Encountered in Pressurised Water Reactors, SEEN, Paris, 1998, 89-100. 

Energy dispersive measuring devices are most commonly used. Interference effects do occur, which are chiefly caused by fluorescent emissions and matrix defects. Corrections can be made. 

GESS, B., ROHR, D., FLEDRICH, R., SEREDA, M. W., KLEFFNER, L, HUMBERG, A., NOWrrZKI, J., STRECKER, J. K., HALFTER, H. YOUNG, P. 2011. Sodium-dependent vitamin C transporter 2 deficiency causes hypomyelination and extracellular matrix defects in the peripheral nervous system. 7 AfewmjCf, 31,17180-92. 

Ascorbic acid s chemical structure makes it an electron donor and therefore a reducing agent. AA has thus been involved in two different biochemical functions redox/ antioxidant properties and enzymatic cofactor. AA has been demonstrated to be an electron donor for different enzymes. Among these enzymes, three are involved in collagen hydroxylation (Bates et al., 1972 Levene et al., 1972). Two are involved in carnitine synthesis (Nelson et al., 1981 Dunn et al., 1984). The remaining are respectively involved in norepinephrine synthesis (Kuo, 1979) and tyrosine synthesis (La Duand Zannoni, 1964). Deficiency in AA has thus been associated with extracellular matrix defects that are probably involved in vascular problems observed in scurvy. 

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