Small Angle Experiments

If the small angle experiment is run simultaneously, proceed to step 1 of Small Angle Experiments. 

Place the specimen holder with the sample in place. 

If the wide angle and small angle experiments are run simultaneously, the timer is not used. For the wide angle experiment, follow steps 2 to 4 and 6 to 9, timing the exposure by clock. 

Open the camera and remove the film cassette for development, according to manufacturer s instructions. 

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Bordas (1982) suggests that from experience of biological samples in small angle experiments on DORIS there is a limitation to the intensity one can use for a typical specimen due to radiation damage effects, i.e. 

Fig. 1 Phase behavior of CijEs/water/n-octane system for equal volume fraction of water and oil. LTM, MTL and HTM are the low-temperature microemulsion, middle-temperature lamellar and high-temperature microemulsion phase, respectively. The area between the broken lines is the region where the lamellar and microemulsion phases coexist. It is drawn according to X-ray small-angle experiment results...

X-ray photons interact only with the electronic clouds of atoms. As a result, the contrast Kx depends on the number of electrons, and reads in the case of small-angle experiments where relation 4.5 applies [42] ... 

The structure of microemulsions have been studied by a variety of experimental means. Scattering experiments yield the droplet size or persistence length (3-6 nm) for nonspherical phases. Small-angle neutron scattering (SANS) [123] and x-ray scattering [124] experiments are appropriate however, the isotopic substitution of D2O for H2O... 

Figure 9.22 illustrates how a CARS experiment might be carried out. In order to vary (vj — V2) in Equation (9.18) one laser wavenumber, Vj, is fixed and V2 is varied. Here, Vj is frequency-doubled Nd YAG laser radiation at 532 nm, and the V2 radiation is that of a dye laser which is pumped by the same Nd YAG laser. The two laser beams are focused with a lens L into the sample cell C making a small angle 2a with each other. The collimated CARS radiation emerges at an angle 3 a to the optic axis, is spatially filtered from Vj and V2... 

In addition to the above techniques, inverse gas chromatography, swelling experiments, tensile tests, mechanical analyses, and small-angle neutron scattering have been used to determine the cross-link density of cured networks (240—245). Si soHd-state nmr and chemical degradation methods have been used to characterize cured networks stmcturaHy (246). H- and H-nmr and spin echo experiments have been used to study the dynamics of cured sihcone networks (247—250). 

An important design parameter is the jet angle. Normally the jet should be parallel to the table or the inner back wall and can thus be treated as a normal wall jet. If the jet has a small angle upward from the table, the wall jet equations may be unsatisfactory and experiments may be necessary. 

By small-angle neutron scattering experiments on water/AOT/hydrocarbon microemulsions containing various additives, the change of the radius of the miceUar core with the addition of small quantities of additives has been investigated. The results are consistent with a model in which amphiphilic molecules such as benzyl alcohol and octanol are preferentially adsorbed into the water/surfactant interfacial region, decreasing the micellar radius, whereas toluene remains predominantly in the bulk hydrocarbon phase. The effect of n-alcohols on the stability of microemulsions has also been reported [119],... 

Isothermal crystallization was observed by means of SAXS and a polarizing optical microscope (POM, OLYMPUS, BX or BHS-751-P). The SAXS experiment was carried out using synchrotron radiation on the beam line BL40B2 of SPringS (SP8) at JASRI in Harima and at the BL-10C small angle installation of the Photon Factory (PF) at KEK in Tsukuba. 

The size and shape of polymer chains joined in a crosslinked matrix can be measured in a small angle neutron scattering (SANS) experiment. This is a-chieved by labelling a small fraction of the prepolymer with deuterium to contrast strongly with the ordinary hydrogenous substance. The deformation of the polymer chains upon swelling or stretching of the network can also be determined and the results compared with predictions from the theory of rubber elasticity. 

Recent small angle neutron scattering experiments shed uncertainty on the assumption of affine deformation (14-18). There... 

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