Pillar shape

The product crystals find industrial application as a component raw material for optical glass, fibreglass, Braun tubes, electric condensers, barium ferrite, etc. Needles shaped crystals are obtained at high pH, while pillar-shaped crystals are formed at neutral pH. The formation of carboxyl ions is via hydroxy ions at high pH, but at neutral pH it may accompany the production of hydrogen sulphide, as... 

We have already stated In the previous paper O) that, under the supersaturation pressure of 5 to 8 MPa, the longitudinal growth rate of a rectangular pillar-shaped crystal attained 1.0 mm/mln.MPa In the same concentration, whereas the transverse growth rate was too low to detect. 

Taking, for instance, Al, with a melting point of 660 °C and a web substrate temperature of 50 °C, zone I formations will be created (porous structure, pointed crystallites, large voids) and up to 250 °C, formations in the transitional area (densely packed fibers) will appear. Up to 450 °C zone II (pillar-shaped crystallites), and above this temperature zone III (conglomerate-type crystallites) formations will be seen. Because of the relatively low maximum thermal stress that may be applied to polymer webs, the growth in metallized layers on polymer webs mainly occurs in Zone I or in the transitional zone. The different growth is also evident from comparison of cooling drum and free-span coater methods. 

The inner surfaces of the pillar[5]- and pillar[6]arene cavities are negative because alkojq groups on the rims are electron-donating moieties. Compared with an open-ended calix[5]arene structure, their pillar-shaped structures contribute to enhance the 7t-electron density of their cavity. Therefore, pillar[5]- and pillar[6]arenes prefer to accommodate electron-poor molecules, such as cationic molecules and molecules containing electron-with-drawing groups, in their cavities. ... 

In this chapter, first, the assembled structures of the cyclic pentamers, pillar[5]arenes, and cyclic hexamers, pillar[6]arenes, in the crystal state are discussed. They have been most widely used because they can be obtained in relatively good yields. Pillar[5]- and pillar[6]arenes possess clear cylindrical pillar-shaped structures when compared with other macrocyclic compounds. Therefore, it is envisioned that the assembled structures of pillar[n]arenes in the crystal state should be easily analyzed and this pre-organized conformation will facilitate the formation of herringbone, one-dimensional channel and slipped-stacked pillar[w]arenes. It has been revealed that the assembled structures of pillar[n]arenes largely depend on the ring size, substituents and solvents used to obtain the single crystal. The assembled structures of pil-lar[ ]arenes contribute to the gas and organic vapor adsorption properties. 

The unit model with two imidazolium bis(trifluoromethanesulfonyl)amide moieties was a white solid, indicating that the pillar-shaped macrocyclic structure and modification with 10 imidazolium bis(trifluoromethanesulfonyl)-amide groups contributed to the liquid state at room temperature. The liquid pillar[5]arene 6.29 showed moderate ionic conductivity (6.00 x 10 S cm ) at 324 K. The introduction of soft and flexible tri(ethylene oxide) moieties also... 

Pillar[w]arenes Easy-to-Make Pillar-Shaped Macrocyclic Hosts for Supramolecular Chemistry... 

In 2008, we reported the discovery of a new class of pillar-shaped macrocyclic host compounds, known as pillar[ ]arenes [7]. Compared with typical host molecules, there are several unique advantages associated with pillar[ ]arenes... 

Polymer pellets of isotactic polypropylene (iPP) were melted in a laboratory hot press for 15 min at 230 °C and 10 MPa, and then quenched in ice water (0 °C) or boiling water (100 °C). To control the crystallinity of the iPP sample, we annealed the sample sheets prepared at 0 °C for 2 hr at various temperatures from 40 to 140 °C. Square pillar shaped test specimens were cut out from a 1 mm thick sheet and used for the measurements. Double-edge notched sample specimens with the gauge length of 2 mm were used for the temperature dependence and the dumbbell shaped specimen with gauge length of 5 mm for the elongation speed dependence. 

Figure 6- Cleavable fracture of a specimen of granite concrete- There are visible microfractures on the boundary of granite grain (a) and pillar—shaped contact layer and between contact layer and cement paste (b)-...

Fig. 6.23 A FEG-SEM micrograph of the hopper ash (REA), where PP and SP designate pillar shaped and spherical shaped particles...

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