Crystal destruction

Fig. 5. Log-iog plot illustrating the hardness dependence of density for PE samples crystallized from the melt. The plot yields two straight sections which can be ascribed to two preferential deformation modes a crystal destruction and b compression of amorphous domains...

Fig. 7. Strain boundaries for the crystal destruction zone (assuming a spherical shape) round the Vickers indent for two PE samples with a = 0.95 and a = 0.21 respectively...

Concluding this brief survey of the effects of cosolvents and temperatures on noncovalent binding forces between proteins, we may assume that while the dielectric constant may play a role in the cryoprotection of protein crystals, changes in interaction forces may confer protection or in some cases be responsible for crystal destruction. However, we must bear in mind that hydrogen bonds and salt links involved in the regions of contact between proteins will be strengthened and/or stabilized at low temperatures within certain limits of pan values, which should aid in the cryoprotection of protein crystals. 

J. A. McDonald, B. J. Baum, D, M. Roseubeg, J. A. Kdman,S. C. Brin, and R. G. Crystal. Destruction of a imJor extracellular adhesive glycoprotein (fibronccrin) of human fibroblasts by neutral proteases from polymorphonuclear leukocyte granules. Lab. Invest. 40350 (1979). 

In this paper a mathematical model is applied which allows for high-silica faujasites the prediction of their crystal destruction for different hydrothermal conditions and treatment periods. The model is based on the assumption that the dissolution of the framework proceeds with a water attack at surface Si-O-Si bonds. It is shown that the rate of decomposition of such high-silica faujasites is mainly controlled by the size of the shrinking surface of the crystals. 

Oxidative processes are localized in amorphous interlayers, in interfibrillar regions and others. Crystallinity and crystals sizes increase at initial stages of oxidation [303] it also means that oxidation is localized in amorphous part. Destructive decay of passing macromolecules in amorphous interlayers release them and facilitates folding of chains into crystals. Destruction and amorphicity of crystals takes place only at deep stages of oxidation. Solubility of oxygen in polymer depends not only on polymer crystallinity but on microstructure of amorphous or defect sections. 

Figure 6.15 Four Circle Diffractometers Two examples (a) and (b) of single photon counting devices. The goniometer head positions the diffracting crystal in the path of an incident X-ray beam. The devices allow for rotation of the mounted crystal through at four complete arcs (designated 4>, uj, 20 and k or x) in order to detect as many bW-reflections (reciprocal lattice points) as possible by diffraction counter prior to crystal destruction by the incident beam (Reproduced from Drenth, 1994, Fig. 2.9).

In the comparison of BC and the BC-PVA composite, the crystallinity of BC in the composite was decreased by 50%. By immersing wet BC pellicles in polyvinyl alcohol [PVA] solution, PVA could penetrate the BC network structure and filled the pores. Acetal linkages were formed in the BC-PVA composites by a cross-linking reaction, which made PVA insoluble in water. However, the crystal destruction was observed after the cross-linking [84]. 

The WD spectrometer (Figure 1) behaves as an X-ray monochromator. Selected crystalline materials are used to diffract lines in the fluorescence X-ray spectrum. When a beam of X-rays is directed at certain crystalline materials. X-ray photons are reflected off the various atomic layers in the crystal. Destructive interference occurs between almost all reflected photons, except those that satisfy the Bragg equation ... 

In semicrystalline polymers, scission occurs by a mechanism typical of the amorphous phase which results in crystal destruction. The crystallinity index is therefore reduced, an effect actually recorded with all semicrystalline polymers subjected to grinding. 

In Davisson and Germer s experiment, the waveforms of an electron beam reflected off different layers of a crystal destructively interfere at some angles, and no current is measured at the detector. What has happened to the mass and the charge on the electrons Is mass not conserved for quantum particles ... 

Radiochemical degradation occurs by three simultaneous competitively distinct processes [48, 49] oxidative scission in amorphous phase, crosslinking and crystal destruction and/or chemicrystallization. The increase of polymer density was explained by crystallization in amorphous regions. In fact, chemicrystallization induces only an apparent increase of crystallinity and of density, observed in PE oxidation too, due to the formation of polar groups (—OH, >C = 0, —COOH) which would increase intermole-cular forces of attraction, resulting in a high density [50]. 

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