23. Detection of PMPs Phase Detector Voltage Controlled Oscillator Loop Filter R C L Frequency Meter DC error signal
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Hinweis der Redaktion
Ni 30 Fe 70 An Alloy of Ni and Fe - Invar films, “Invariable” due to low thermal expansion at 36% NI NdFeBLa neodymium-iron-boron-lanthanum powder can be magnetized to a magnetic moment 50 times greater than that of Dynabeads. On the other hand, NdFeBLa also has a high density (8.9 g/cm3), wide variation in particle diameter, and is susceptible to corrosion. Corrosion is reduced by encapsulating the particles in glass, a technique that also provides an ideal surface for further chemical modification
Dissolve iron (III) chloride (270 g) and iron (II) sulphate (153 g) in 1 l distilled water. Set a pH value of 9.5 by adding caustic soda while stirring. After completed precipitation set the pH value to 5.0 by stirring and adding hydrochloric acid and heat to 100° C. After cooling the dispersion, wash the precipitation, until the electrical conductivity of the filtrate is <10 μS/cm. Stabilising of the superparamagnetic particles takes place by mixing an aqueous stabiliser solution or a stabiliser solution containing low-boiling polar solvents with the magnetic particles at room temperature. In this, the stabiliser solution, depending on the desired properties, can consist of pure stabiliser substances or of mixtures of stabiliser substances. In order to accelerate dispersion and stabilisation, the dispersion can be stirred or treated with ultrasound. If low-boiling organic solvents are used, these will be removed after stabilisation, by vacuum evaporation or dialysis.
Nano clusters 20 – 50 nm with individual nano particles 10-15 nm Estapore particles have smaller nano-particles which range from 5 -20 nnm