Ultrafine structure

Ultrafine Structures in Coal Components as Revealed by Electron Microscopy... 

Since the work reported by McCartney et al. (9), ultrathin sections of other, more heterogeneous components and mixtures of components of coals of different rank have been prepared and observed. Procedures for minimizing artifacts have been learned and followed, and experience in observation has led to avoiding obvious faults. These sections were often not as large and continuous as those of homogeneous vitrinites, but adequate areas were available for electron microscopy. Observations of these various components revealed ultrafine structures of different size and form. Some of the structures can be correlated with those deduced from other direct or indirect study techniques others are unfamiliar and novel, and suggested interpretations are tentative. 

Physical properties Density Specific gravity Pore structure True density as measured by helium displacement Apparent density Specification of the porosity or ultrafine structure of coals and nature of pore structure between macro, micro, and transitional pores... 

King, J. G., and Wilkins, E. T. 1944. Proceedings of the Conference on the Ultrafine Structure of Coal and Cokes. British Coal Utilization Research Association, London, p. 45. 

Blayden, H.E. Gibson, J. Riley, H.L. Proc, Conf, Ultrafine Structure of Coals and Cokes, BCURA (London) 1944, p.176. 

FIGURE 5.11 Transmission electron micrograph of stained transverse section showing the ultrafine structure of the CMC of apposed fiber cuticle cells in human hair. The CMC comprises two unstained modified membranes (P-layers) and an intercellular 8-layer of higher staining intensity. Note also the internal laminae in the 8-layer with thickness approximately 0.005 p,m. An intracellular membrane associated layer (i) forms a narrow band on the underside of a fiber-cuticle cell. The dark stained band (a) is the surface a-layer of exocuticle (exo) from an underlying cuticle cell. The section was stained with osmium tetroxide, uranyl acetate, and lead citrate after prior reduction with thioglycolic acid. Bar equals 0.1 p.m. 

Electron microscopy has also been employed as a means of elucidating coal structure granules as small as 200 to about 1000 J.m in diameter have been observed. In addition, it has been reported that particles range from 250 A in a low-rank coal to 100 A in a high-rank coal while two general ranges for the ultrafine structures have also been observed one <100 J.m and the other >100 pm with some of the particles in the form of polygonal platelets. 

Boddy, R.G.H.B., Proc. Conf Ultrafine Structure Coal and Coke, BCURA, London, 1943, p 336. 

Transmission electron microscopy (TEM) is a powerful method for imaging ultrafine structures of materials. In principle, TEM apparatus provides high resolution enough to observe molecules in subnanometer scale. However, it is not so easy, in practice, to apply TEM for imaging supermolecules on an atomic level owing to their thermal oscillation under the measurement conditions. Thus, TEM analysis of supermolecules has been generally discussed on a nanometer scale up to the present time. 

Consolidated Research Institute for Advanced Science and Medical Care (ASMeW), Waseda University, Tokyo, Japan Division of Ultrafine Structure, Department of Pathology, Research Institute of International Medical Center of Japan, Tokyo, Japan... 

The main concern is the chemical compatibility of the ink with the substrate. In this context it is important to define in advance the requirements for the conductor structures and the preferred substrate material. This is essential in order to produce ultrafine structures, for example with conductor widths of 50 pm and 50 pm conductor spacing, of good quality in terms of conductance, adhesion, and reliability. 

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