Bridge-shaped channel

Catalytic Properties. In zeoHtes, catalysis takes place preferentially within the intracrystaUine voids. Catalytic reactions are affected by aperture size and type of channel system, through which reactants and products must diffuse. Modification techniques include ion exchange, variation of Si/A1 ratio, hydrothermal dealumination or stabilization, which produces Lewis acidity, introduction of acidic groups such as bridging Si(OH)Al, which impart Briimsted acidity, and introducing dispersed metal phases such as noble metals. In addition, the zeoHte framework stmcture determines shape-selective effects. Several types have been demonstrated including reactant selectivity, product selectivity, and restricted transition-state selectivity (28). Nonshape-selective surface activity is observed on very small crystals, and it may be desirable to poison these sites selectively, eg, with bulky heterocycHc compounds unable to penetrate the channel apertures, or by surface sdation. 

Also deoxycholic acid (6) crystallizes in an inclusion lattice with channel-shaped cavities 13). Figure 3 shows that they are formed by facing molecules of deoxycholic acid, 4). This characteristic structural unit is a double layer of head-to-tail linked deoxycholic acid molecules at which specific H-bridges between hydroxy and carboxy groups are the decisive fact. The channels as such (e.g. in case of the orthorhombic crystal, see Fig. 3) are lined with lipophilic groups. Thus only van der Waals contacts are kept between the included guest molecules (also for polar molecules like acetone, Fig. 3) and the molecules of the channel wall. 

Cutting charges serve to cut through iron plates, cables, bridge trusses etc. They are constructed on the principle of - Shaped Charges, but are not rotationally symmetrical their shape is that of long channels (grooves). 

MWNTs can be electrically induced into aligned chains in a styrene-based SMP/carbon black (CB) composite and serve as long-distance conductive channels to bridge the CB aggregates in the SMP matrix. Compared with the samples without nanotubes [e.g., CB (15 wt%)/SMP composite] or with randomly distributed nanotubes e.g., MWNT (random, 1 wt%)/CB (15 wt%)/ SMP composite], the electrical resistivity is reduced by over 100-fold in composites with chained nanotubes [e.g., MWNT (chained, 1 wt%)/CB (15 wt%)/SMP composite]. With a DC voltage of 25 V, the MWNT (chained, 1 wt%)/CB (15 wt%)/SMP composite demonstrates much faster shape recovery than either the CB (15 wt%)/SMP composite or the MWNT (random, 1 wt%)/ CB (15 wt%)/SMP composite (Figure 2.7). ... 

The unit consist of an Y-shaped junction with integrated strictures immediately before the connects and a bypass, which bridges both inflow channels. The inlets of the bypass are equipped with apertures which selectively prevent the inflow of dispersed phase fluid while enabling the passage of the continuous phase (see Fig. 4, part 1). 

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