Microstructures/microstructured materials probes

A number of techniques have been employed that are capable of giving information about amorphous phases. These include infrared spectroscopy, especially the use of the attenuated total reflection (ATR) or Fourier transform (FT) techniques. They also include electron probe microanalysis, scanning electron microscopy, and nuclear magnetic resonance (NMR) spectroscopy. Nor are wet chemical methods to be neglected for they, too, form part of the armoury of methods that have been used to elucidate the chemistry and microstructure of these materials. 

Many other atom-probe analyses of different phases in different types of steels exist as steels are one of the most important materials. It is possible to investigate how the magnetic properties of alloys are correlated to the microstructures of different phases in the alloys.57,58,59 The chemical contents, growth process and structures of metallic carbides in different alloy steels have been studied with the field ion microscope and the atom-probe field ion microscope.60 61 62 63 We refer the reader to some of the original papers published on these subjects. 

Our approach [9], which we refer to as Representative Microstructure Finite Elements (RMFE), probes both the structural and the functional length scales of the material. The method is a variant on standard finite elements in that the constitutive equation is replaced with a representative microstructural problem based on the local microstructure within each element (cf. [10]). In the following paragraphs, we summarize the major features and recent improvements in our method and then demonstrate it on a test problem. 

The analysis viscoelasticity performed by David Roylance [25] is a nice outline about the mechanical response of polymer materials. This author consider that viscoelastic response is often used as a probe in polymer science, since it is sensitive to the material s chemistry and microstructure [25], While not all polymers are viscoelastic to any practical extent, even fewer are linearly viscoelastic [24,25], this theory provide a usable engineering approximation for many applications in polymer and composites engineering. Even in instances requiring more elaborate treatments, the linear viscoelastic theory is a useful starting point. 

The photochemistry of small molecule LC materials has been an active area of research for many years and has been reviewed recently [9]. The photochemistry of LC polymers, per se, has received much less attention although two brief reviews have appeared [5,10], and there has been a considerable effort to apply some simple photochemical transformations such as trans-cis photoisomerization, to the development of practical devices [1-6]. This section is divided into three parts. In Part A, chromophore aggregation, which seems to be important in almost all the cases in which careful UV-Vis and/or fluorescence studies of films of pure LC polymers have been made, is explicitly discussed. Part B is devoted to a thorough review, organized by chromophore type, of the photochemistry and related photophysics of LC polymers. No attempt has been made to extensively cross-reference the work on LC polymers to the hundreds of papers and reviews on analogous non-LC compounds. However, when it seemed particularly appropriate or interesting, experiments related to optical applications of the photochemistry of LC polymers are briefly described. In Part C, a few experiments are described in which a classical photophysical method, fluorescence spectroscopy, is used to probe the microstructures of some LC polymers. 

The EDS type of X-ray spectrometer is commonly included as a part of SEMs and TEMs. The reason for using EDS rather than WDS is simply its compactness. With EDS in an electron microscope, we can obtain elemental analysis while examining the microstructure of materials. The main difference between EDS in an electron microscope and in a stand-alone XRF is the source to excite characteristic X-rays from a specimen. Instead of using the primary X-ray beam, a high energy electron beam (the same beam for image formation) is used by the X-ray spectrometer in the microscopes. EDS in an electron microscope is suitable for analyzing the chemical elements in microscopic volume in the specimen because the electron probe can be focused on a very small area. Thus, the technique is often referred to as microanalysis. 

Rheology is increasingly being coupled to other analytical test methods for more comprehensive material characterizations. Many of these developments are driven by research needs for broadened characterization capability. For fundamental studies of detergent systems this offers a broad suite of methods to probe surfactant mesophases and internal microstructure. 

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