Scattering electron microscopy

Characterization. When siHca gel is used as an adsorbent, the pore stmcture determines the gel adsorption capacity. Pores are characterized by specific surface area, specific pore volume (total volume of pores per gram of solid), average pore diameter, pore size distribution, and the degree to which entrance to larger pores is restricted by smaller pores. These parameters are derived from measuring vapor adsorption isotherms, mercury intmsion, low angle x-ray scattering, electron microscopy, gas permeabiHty, ion or molecule exclusion, or the volume of imbibed Hquid (1). 

Size and homogeneity of liposomes are important in their use as drug carriers, since these characters affect the pharmacokinetics and distribution of liposomes in vivo. Light scattering, electron microscopy, NMR, and gel filtration are used for evaluating liposomal size and homogeneity (32,33)... 

Electron diffraction Wide-angle x-ray scattering Electron microscopy Density... 

Small-angle neutron scattering (SANS) can be applied to food systems to obtain information on intra- and inter-particle structure, on a length scale of typically 10-1000 A. The systems studied are usually disordered, and so only a limited number of parameters can be determined. Some model systems (e.g., certain microemulsions) are characterized by only a limited number of parameters, and so SANS can describe them fully without complementary techniques. Food systems, however, are often disordered, polydisperse and complex. For these systems, SANS is rarely used alone. Instead, it is used to study systems that have already been well characterized by other methods, viz., light scattering, electron microscopy, NMR, fluorescence, etc. SANS data can then be used to test alternative models, or to derive quantitative parameters for an existing qualitative model. 

The study by low-angle X-ray scattering, electron microscopy, and differential scanning calorimetry of the mesophases obtained by dissolution of BSB copolymers in preferential solvents for the polystyrene block and of dry BSB copolymers obtained by slow evaporation of the solvent from the mesophases has allowed to establish the respective effect of different factors which control the structure of the mesophases and their geometrical parameters. It has been shown that the nature, concentration, polymerization of the solvent, and temperature have the same effect on BSB copolymers as on SB copolymers35,88-91. ... 

At the same time investigations using light scattering, electron microscopy, positron annihilation, dielectricity and transport properties 30,- ) indicated the surfactant molecules not to be Involved in associations to colloidal size aggregates at these low water contents. The low light scattering intensity rather points to the surfactant molecules not to be inter-associated (Fig. 7). 

Primmer T. J. and Shaw H. F. (1987) Diagenesis in shales evidence from back-scattered electron microscopy and electron microprobe analyses. Proc. Int. Clay Conf, Denver, CO, vol. 8, pp. 135-143. 

In some attempted syntheses of block copolymers, random copolymers may result during the secondary processes of chain reshuffling. Thus, NMR methods, particularly 13C-NMR spectroscopy, should be used to determine the presence of the heterodyads. In addition, DSC, light scattering, electron microscopy, small angle X-ray scattering, and thermomechanical analysis can also be used to distinguish between block and random structures. 

Naturally, a fundamental requirement is the determination of the structure of the molecular sieves imder study (cf. Voliune 2) through techniques such as X-ray diffraction, neutron scattering, electron microscopy and so on. However, a remarkably broad variety of methods and tools are at our disposal for characterizing the physical and chemical properties of molecular sieves. Voliune 4 of the series Molecular Sieves - Science and Technology focuses on the most widely used spectroscopic techniques. Thereby, the contributions to this voliune not only review important applications of these techniques, but also comprise, to a greater or lesser extent, the basic principles of the methods, aspects of instrumentation, experimental handling, spectra evaluation and simulation, and, finally, employing spectroscopies in situ for the elucidation of processes with molecular sieves, e.g. synthesis, modification, adsorption, diffusion, and catalysis. 

Cellulose, which Is one of the most abundant organic substances found In nature, has been extensively studied by various techniques such as x-ray scattering, electron microscopy, IR and Raman spectroscopy, NMR spectroscopy etc. However, the crystal structure and noncrystalline state are not yet solved for cotton, ramie, bacterial and valonla celluloses which can be easily obtained in pure form. Cross-polarization/magic angle spinning(CP/MAS) C NMR spectroscopy is a promising new method to study these unsolved problems of cellulose, because this method is very sensitive to local molecular conformations and dynamics. 

In order to estimate the molecular dimensions of nanosponges, we appHed dynamic light scattering and size-exclusion chromatography (SEC) to the solutions of the new species and low-angle X-ray scattering, electron microscopy, and scanning atomic force microscopy to the dry material [236, 238-240]. 

Exchangeable cation Neutron scattering" X-ray scattering" Electron microscopy Viscosity Light scattering Chloride exclusion ... 

Jennings and Jerrard (I S3) made a detailed comparison of the particle sizes of two commercial silica sols by light-scattering electron microscopy and ultracentrifu-gation. 

Penetrating radiation X-ray radiography X-ray tomc aphy y-ray radiography Neutron radic aphy Neutron scattering Electron microscopy Electromagnetic (wavelengths below about 1 mn) and particle radiation... 

Yang P and Gu Y (2012), Synthesis of a novel benzoxazine-containing benzoxazole structure and its high performance thermoset , J Appl Polym Sci, 124, 2415-2422. Yoonessi M, Toghiani H, Wheeler R, Porcar L, Kline S and Pittman Jr C U (2008), Neutron scattering, electron microscopy and dynamic mechanical studies of carbon nanofiber/phenolic resin composites . Carbon, 46, 577-588, and references therein. Yosomiya R (1990), Adhesion and Bonding in Composites, New York, Marcel Dekker, l-A. 

Giacomelh, C., Le Men, L., Borsali, R., et al. (2006) Phosphorylcholine-based pH-responsive diblock copolymer micelles as drug dehvery vehicles Light scattering, electron microscopy, and fluorescence experiments. Biomacromolecules, 7, 817-28. 

These most interesting features raise important but difficult questions of characterization concerning composition, size, persistence length, shape, structure, etc. of the entities formed. To this end, an array of physicochemical methods is required and must be put to use, such as vapor phase osmometry, differential scanning calorimetry, electrospray mass spectrometry, NMR spectroscopy, gel permeation chromatography, light scattering, electron microscopy, near field microscopies, etc.). (For a relevant case, see Ref. 37.)... 

Yoonessi, M Toghiani, H., Wheeler, R., Porcar, L Kline, S and Pittman, C.U. (2008) Neutron scattering, electron microscopy and dynamic mechanical studies of carbon nanofiber/phenolic resin composites. Carbon, 46,... 

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