Amorphous disordered

This work is based on the doctoral thesis of Prasad Rao [8] it stemmed from the early work of Santiago, Mulay et al. (Cf. ref. 2a). Amorphous (disordered) carbons (Cabot Co. s Monarch 700, CSX-203, etc.) were used after appropriate desulfurization. Some of these carbons were graphitlzed at high temperatures (2773 K). The above CMC samples were doped with boron in the range from 170 to 260 ppm. 

In such an exotic field of materials science as the amorphous (disordered) solids, one of the fundamental problems studied extensively is how to obtain insight into the stracture. Currently, it seems that versatile studies are needed to elucidate the amorphous structure. In other words, in addition to various direct and indirect structural techniques performed under fixed conditions (X-ray diffraction, Raman scattering, infrared absorption, X-ray absorption, to name a few), the investigation of structural modifications introduced by changes in composition, temperature, or pressure or induced by band-gap illumination may prove fruitful. 

A distinction should be made between solvent plasticizers and nonsolvent plasticizers. With an amorphous polymer, any plasticizer is a solvent plasticizer— i.e., under suitable conditions the polymer would eventually dissolve in the plasticizer. With a crystalline or semicrystalline polymer, there are some compounds which enter both the crystalline (ordered) and the amorphous (disordered) regions. These are true plasticizers-sometimes they are called primary plasticizers. If, on the other hand, only the amorphous regions are penetrated, the compound may be considered as a nonsolvent plasticizer, also known as a secondary plasticizer, or softener. Such softeners are used sometimes as diluents for the primary plasticizer. 

The initial sensitizer anion presence makes recombination of mobile holes possible in the dark regions. Which are the compensator sites Here, there exist different explanations. One possibility is that some of the electro-optic dye molecules present in photorefractive composites to provide refractive index change may become charged positively. An alternative theory in the case of amorphous materials is that the amorphous disorder leads to defect sites forming local potential minima at which positive charge may be immobilized (Figure 5). 

It is the heteropoiysaccharides of plants that bestow cellulosic composites with the ability to absorb impact, the ability to absorb moisture, and the ability to create pores in the form of free volume in amorphous (disordered or para-crystalline) materials [58,59]. Modification by reducing molecular regularity has the additional benefit of creating a transition from a focus on mechanical (structural) functions to an emphasis on energy storage and gel formation. Reduction in order translates into ease of hydrolysis, enzyme accessibility, rate of nutrient release for decay organisms, water absorption and swelling. Reduction in order is achieved by the introduction of monosaccharide units, and of bond types, which differ from those of cellulose. The principal monosaccharides involved in the heteropoiysaccharides of plants are shown in O Fig. 12. 

In the remainder of this paper, adsorption models for adsorbent characterization based upon both amorphous (disordered) and idealized (simple... 

Silylated catalysts prepared from methoxytrimethylsilane [71,85] contacted with amorphous, disordered mesoporous titanosUicate (2 mol%) followed by deposition of Au via DP resulted in an increase in PO production rate from 52 to 67 gpo kg f h over the unsilylated catalyst at 150 °C. There was no significant effect on H2 efficiency (an increase from 33.3% to 35.3%). Catalyst deactivation rate appears to have been decreased slightly, 58% retention of activity over the first 4 h relative to 44% for the unsilylated catalyst. SUylation in combination with Ba promotion and the high Ti content of the disordered mesoporous materials has resulted in some of the most active catalysts thus reported with a PO rate of 92 gpo kg j h at 150 °C. 

Two-dimensional NIR spectroscopy has been used for studies on the conposition-dependent spectral variations in EVA copolymers. As a result, additional assignments of bands were made to ethylene units in amorphous, disordered, and orthorhombic crystalline phases (73). 

Applied Spectroscopy 53,No.8,Aug.l999, p.919-26 TWO-DIMENSIONAL NEAR-INFRARED CORRELATION SPECTROSCOPY STUDIES ON COMPOSITION-DEPENDENT SPECTRAL VARIATIONS IN ETHYLENEA EVYL ACETATE COPOLYMERS ASSIGNMENTS OF BANDS DUE TO ETHYLENE UNITS IN AMORPHOUS, DISORDERED, AND ORTHORHOMBIC CRYSTALLINE PHASES Yanzhi Ren Shimoyama M Ninomiya T Matsukawa K Inoue H Noda 1 Osaki Y... 

Carbon materials are classified into two kinds graphitic carbon, which has a normally layered, ordered crystal structure and hard carbon, which has an amorphous, disordered crystal structure. 

Hopping motions of ions at short times are influenced by the surrounding molecules, leading to a bounce-back mechanism that causes (Altf (t)) to be lower at short times than it would be if the long time behavior was extrapolated to zero (9,10). As a result the real conductivity a (co) for polymers and most amorphous disordered solids is a constant (cro) at low frequencies but obeys a power law (to , 0 < m < 1.0) at high frequencies (9,10). 

On the other hand, according to the microscopic nature of the absorption of the IR photons, it occurs also with amorphous, disordered, and defective solids. For this reason, vibrational spectroscopies (in particular IR spectroscopy) represent very useful techniques for the structural characterisation of non-metalUc soUds. 

ITEM images, whieh show dispersed smaller size 2-A nm) Pt partieles. At this juncture, it is to be noted here that the cluster size inereases with inerease in metal loading, however, the increase is marginal as eompared to the eommereial (amorphous/disordered) earbons. It can be seen from these figures that the Pt nano-partieles are, although, uniform with a size distribution of about... 

Mechanical behavior of polyolefins is firstly dependent on their semicrystalline nature. Generally, polyolefins exhibit three phases a tridimensional ordered phase, an amorphous disordered phase, and an interfacial layer between the two phases. The relative content of these morphological forms influences all properties that depend on the response of each phase on the external tensions. 

In oxidic mineral glasses, a number of investigations [77, 70, 78] have shown that and Si chemical shifts depend in a systematic fashion on bond lengths and bond angles - geometry parameters that are essential for the understanding of the amorphous disorder in these systems (vide infra Sect. 4.6). 

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