Light-diffraction techniques

Boron is a light atom. Compared with other atoms in the crystal, B has a relatively stronger scattering power for electrons than that for X-ray. Thus the electron diffraction technique has been successfully applied to study positions of boron atoms in several other crystals [10, 29]. We study the position of B atoms in the crystal of (Yo eCao 4)(SrBa)(Cu2 5B0 5)07 s by means of the image processing technique. 

A hindrance to the elucidation of membrane structure is, of course, the material itself. Membranes are rather intractable lipoprotein systems. Their lipid, protein, and carbohydrate contents are variable both quantitatively and qualitatively since they cannot be crystallized, a detailed analysis by x-ray diffraction is impossible, and since they do not form solutions, the use of hydrodynamic or light-scattering techniques is quite limited. Electron microscopy has been the major physical method, but it is becoming increasingly clear that the electron microscope, at least at present, is incapable by itself of clarifying membrane structure on the molecular level (47). Despite an extensive literature, there is no general... 

The ability of diffraction techniques to determine size is in most cases a direct function of the degree of monodispersity of the suspension being tested. Several alternative techniques are available, dependent on the size of the particles. Some suspensions exhibit higher order Tyndall spectra for incident white light. Size determination is then easily made. 

The special properties of OTEs that permit the use of transmission spectro-electrochemical techniques are often at cross purposes with the acquisition of reliable electrochemical data. The desire to have the superior electrical properties of bulk conducting materials, and thereby reliable electrochemical data, together with the power of a coupled optical probe led groups to develop various diffraction and reflection approaches to spectroelectrochemistry. Light diffracted by a laser beam passing parallel to a planar bulk electrode can be used to significantly increase the effective path length and sensitivity in spectroelectrochemistry [66]. 

To understand the resolution of electron microscopes and later diffraction techniques the wave approach is more instructive. The resolving power of electron microscopes is substantially better than that of a light microscope, since the wavelength of the electrons, given by the de Broglie relation... 

Brockway and Jenkins applied electron diffraction techniques as early as 1936 to determine a 7 d geometry for (CH.t)4Ge, and a Ge—C bond length of 1.98 A (31). In the light of more recent microwave data which indicate a substantially shorter Ge—C bond length in the series of methylgermanes (62, 120, 161), this structure has been redetermined (91) to yield a more reliable Ge—C bond length of 1.945 A. 

Powder particle size distribution is normally measured using laser light diffraction spectrophotometry (see Section 22.2.11.2). The mechanical stability of agglomerated particles can be determined by using this technique to measure the fines created by subjecting the sample to a defined mechanical treatment. 

The film thickness obtained by the light reflectance technique is compared with that from low angle X-ray diffraction and a theoretical value in Table IV. The larger value from X-ray... 

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