Microspheres, definition

Another two-phase composite is chemically or physically blown foam, composed of polymer and voids only (i.e. conventional foamed or cellular polymer). Its compositions lie along the polymer-void border of Fig. 7, and it, too, is limited by the maximum volume fraction of voids allowed, while still maintaining the definition of a foam. The limits mentioned define the allowed compositions for syntactic foams and determine the area within the diagram where they are located. One limiting case is point B which represents the composition of microspheres (0.74), polymer (0.11), and voids (0.15). The microspheres, in this case, are arranged in a hexagonal close packing 85). 

In most cases, Do is about 10 cm s, and it then follows that the characteristic radius of an UME is smaller than 6 [im. However, it is important to notice that Do is sometimes appreciably smaller than 10 cm s if O is a very large molecule, or, more likely, if a viscous or glass-like medium is used planar diffusion would then prevail even at a radius of 6 pm. Note also that a microelectrode with a radius of 100 pm experiences a substantial contribution from spherical diffusion. If the geometry of the electrode differs from the simple disk or microsphere shape, the definition is less clear. In general, the characteristic behavior of a UME is observed if at least one of the dimensions is in the micrometer range. For instance, a band electrode with a width of less than 10 pm behaves as an UME even if it is several mm long. 

In an emulsion, the particles of the internal phase are spherical or liquid droplets that are dispersed throughout a liquid external phase. Even though the particles may be liquid only at elevated temperatures (50-80° C) and semisolid or rigid at room temperature, as long as they appear spherical on careful microscopic examination, they are generally considered to be emulsified rather than suspended. Thus, a clue to the presence of a suspended particle is its lack of sphericity or its definitive lattice structure. Exceptions to this general rule are spherical microspheres and related spherical solid microparticles. 

Definition Glass consisting essentially of calcium and aluminum borosilicates Uses Cosmetic microspheres Trade Name Synonyms Luxsil Cosmetic Microspheres [Potters Ind. http //www.pottersbeads.com] PQ http //www.pqcorp. com]... 

Despite the fact that the presence of microspheres made from non-degradable polymers in pathological arteries induces a generally acceptable inflammatory response, embolisation is not definitive. In fact, revascularisation invariably occurs, excluding this foreign body from the lumen of the vessel at a rate that depends on the material, the animal and the emboiised tissue. The molecular mechanisms occurring in this process are unknown. 

Colloid Probe Atomic Force Microscopy. Colloid probe atomic force microscopy (AFM) uses a microsphere as a probe for the quantitative measurement of surface forces.The main advantage of using a microsphere instead of a sharp tip is the improved definition of the contact geometry and thus the ability to perform quantitative comparisons with theoretical models of interfacial forces. 

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