06-03-2014 дата публикации
Номер: US20140066751A1
A method and apparatus for performing accurate measurements of the magnetic properties of magnetic nanoparticles (MNPs) in both liquid media and biological matrices for providing information on their size, size distribution and concentration in these media and matrices and, resulting in parameters that influence their functionality and effectiveness. 1. An apparatus for determining a size and size distribution of superparamagnetic nanoparticle cores in a sample , the apparatus comprising:a container to hold the sample;a magnetic measurement device configured to perform a magnetization analysis of the sample while in the container and generate magnetization data corresponding to the sample while in the container; and receive the magnetization data from the magnetic measurement device;', {'sub': H', 'H', 'H, 'perform a linear regression analysis of the magnetization data representing an asymptotic region in each of four branches (A, B, C, D) of a plotting of Mvs. 1/H, where Mis the measured magnetization in a magnetic field of intensity H approaching its saturation value and generate a first correlation curve of the form M=α/H+β;'}, {'sub': n', 'sat, 'calculate both a number average particle volume, {tilde over (V)}, and a saturation magnetization, M, of the sample, as a function of the first correlation curve;'}, {'sub': H', 'H, 'combine low field, linear data of Mfor branches A and C, and branches B and D, and obtain two plots of Mvs. H for values of H within a range from −50 Oe to +50 Oe;'}, {'sub': 'H', 'perform a linear regression analysis of the data in each branch and generate a second correlation curve of the form M=γH+δ;'}, {'sub': v', 'sat', 'H, 'calculate a volume average particle volume {tilde over (V)}as as a function of the saturation magnetization value Mobtained from the high field measurements, and using the value of the slope γ for the ratio of M/H;'}, {'sub': v', 'n', 'v', 'n, 'calculate a volume average spherical equivalent magnetic particle ...
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