X-ray interferences

X-ray interference patterns, cell division in sea urchins, equilibrium positions in crystals, Romanesque cathedrals, snowflakes, music, the theory of relativity.f... 

Huxley, H. E., Reconditi, M., Stewart, A., and Irving, T. (2003). X-ray interference evidence concerning the range of cross-bridge movement, and backbone contributions to the meridional pattern. Adv. Exp. Med. Biol. 538, 233-241. 

Reconditi, M., Koubassova, N., Linari, M., Dobbie, I., Narayan, T. Diat,0., Piazzesi, G., Lombardi, V., and Irving, M. (2003). The conformation of myosin head domains in rigor muscle determined by X-ray interference. Biophys.J. 85, 1098-1110. 

Symmetry establishes a ridiculous and wonderful cousinship between objects, phenomena, and theories outwardly unrelated terrestrial magnetism, women s veils, polarized light, natural selection, the theory of groups, invariants and transformations, the work habits of bees in the hive, the structure of space, vase designs, quantum physics, scarabs, flower petals, X-ray interference patterns, cell division in sea urchins, equilibrium positions in crystals, Romanesque cathedrals, snowflakes, music, the theory of relativity. 

The internal structure of copper pyrites, CuFcS2, has been studied by means of their X-ray interference phenomena.8... 

The X-ray interference pattern of the multilayer film of (100 layers) suggested that the film has uniform thickness of around 40 nm. Furthermore, the thickness of the same film was measured directly to be 42 nm using a Talystep. According to the ellipsometry results, the monolayer thickness was 0.45 nm. 

Laue, M. von. Die dynamische Theorie der Rdntgenstrahl-Interferenzen in neuer Form. [A new version of the dynamic theory of X-ray interference.] Ergebnisse der Exacien Naturwissenschaften 10, 133-158 (1931). 

Debye, P., and Scherrer, P. Interferenzen an regellos orientierten Teilchen in Rbntgenlicht. [X-ray interference by disordered particles.] Physik. Z. 17, 277-283 (1916). 

Debye, P. Interferenz von Rontgenstrahlen und Warmebewegung. [X-ray interference and thermal movement.] Ann. Physik 43, 49-95 (1914). English translation in Collected Papers of Peter J. W. Debye, pp. 3-39. Interscience New York (1954). 

A peak will be observed when the diffracted X-rays interfere constructively. This occurs when the path length difference from two neighbouring regions, that is, 2d sin G, equals a multiple of the wavelength of the X-rays. Therefore a peak will be seen when the Bragg condition is satisfied ... 

Further, it was known from the investigations of Davisson and Germer (1927) that in the reflection of beams of electrons by metals deviations occurred from the result to be expected on classical principles, more electrons being reflected in certain directions than in otln rs, so that at certain angles a sort of selective reflection took place. The conjecture was first propounded by Elsasser (1925) that we have before us here a diffraction effect of electronic waves in the metallic lattic.e, similar to that which occurs in X-ray interference in crystals. The exact investigations which were then imdertaken by Davisson and Germer actually gave interference phenomena in precisely tlie same form as the known Lane interference with X-rays. 

Figure 5-35. Small-angle (above) and wide-angle (below) X-ray interference by drawn poly-...

The supermolecular structure of cellulose derivatives - in the present case cellulose esters -is strongly influenced by the degree of substitution and the substitution pattern. With the exception of cellulose triacetate (CTA, tully substituted, DS = 3), most commercially used cellulose esters have a DS of less than three or, in the case of mixed esters, do not have a regular substitution pattern. Therefore, a proper crystallization with well defined X-ray interferences is normally not observed and the materials appear amorphous. 

On the other hand, Hess and coworkers have succeeded in destroying the crystalline order in cellulose fibres by mechanical treatment. (Complete disappearance of the characteristic X-ray interferences). As a result of the treatment, sorptive power and integral heat of sorption increase considerably . 

Starch-water, hydrate formation seems to be an intrinsic condition for the formation of a regular lattice order. The crystalline X-ray interferences disappear if the water content of the system is lowered beyond a certain value, indicating a break down of the 3-dimensional order existing in the hydrated state... 

The X-ray interferences are sharper in soap solutions than in ordinary liquids. This makes it extremely interesting to compare the X-ray investigation with other properties of the soap solutions (Hess and coworkers -When can X-ray interferences disappear with decreasing concentration of the soap ... 

Fig. 34. Occurrence of micelles in strongly concentrated solutions of Na valeriate. Only the X-ray interference corresponding to the long spacing appears, as the micelles do not grow big enough for the short spacing to appear.

At the critical concentration of the valeriate (see Fig. 34, transition from a to b) the Hartley micelles are formed, and these perhaps become somewhat flattened with increasing concentration and chains will start to form (Fig, 34c) whereby the X-ray interference of a long spacing makes its appearance. 

When we add KOH to a soap solution — of fairly high concentration — the viscosity falls and after a minimum rises very steeply (see Fig. 38). The X-ray interference of the long spacing remains the same, thus the thickness of the micelles does... 

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