Microstructured objectives

The electrophoretic deposition (EPD) of small particles, mainly in the nanometer size range, on microstructured objects is a rather inexpensive and simple method, characterized by the short time that is required for layer formation. 

Beta forging working histories for Beta III require imparting enough hot work to reach final macrostructme and microstructure objectives. (3enei ally, reductions in any given forging process are 30 to 50% to achieve desired dynamic and static recrystallization. Very low levels of P reduc-... 

Laminographical approaches can be used for layer-by-layer visualization of the internal microstructure for the flat objects (multilayers, PCBs etc.), that caimot be reconstructed by computerized tomography because of the limited possibilities in rotation. Depth and lateral spatial resolutions are limited by the tube, camera and rotation accuracy. Microfocus X-ray tubes and digital registration techniques with static cameras allow improving resolution. Precision object manipulations and more effective distortion corrections can do further improvement. 

A first example of application of microtomography is taken from life sciences. Here X-ray microscopy and microtomography allows to reconstruct the internal three-dimensional microstructure without any preparation and sometimes even of living objects. Fig. la shows an X-ray transmission microscopical image of bone (femoral head). Several reconstructed cross-sections are shown in Fig.lb. Fig.lc shows the three-dimensional reconstruction of this bone. 

In image mode, the post-specimen lenses are set to examine the information in the transmitted signal at the image plane of the objective lens. Here, the scattered electron waves finally recombine, forming an image with recognizable details related to the sample microstructure (or atomic structure). 

PET fibers in final form are semi-crystalline polymeric objects of an axial orientation of structural elements, characterized by the rotational symmetry of their location in relation to the geometrical axis of the fiber. The semi-crystalline character manifests itself in the occurrence of three qualitatively different polymeric phases crystalline phase, intermediate phase (the so-called mes-ophase), and amorphous phase. When considering the fine structure, attention should be paid to its three fundamental aspects morphological structure, in other words, super- or suprastructure microstructure and preferred orientation. 

At the end of 2003, new research results led to sensational headlines Minerals Cooked Up in the Laboratory Call Ancient Microfossils Into Question was the title chosen by Richard A. Kerr for his article in Science dealing with synthetically prepared silicate carbonates. Their microstructures show morphologies which look exactly like those of filaments which had been assigned as cyanobacterial microfossils of the Precambrian Warrawoona chert formation in western Australia. The synthetic structures consist of silicate-encapsulated carbonate crystals, and in part have a helically twisted morphology reminiscent of biological objects. Simple... 

Membrane-like microstructures are generally several micrometers thick, while the lateral dimensions of the structures and the surrounding package are on the order of a few hundred micrometers. If the layered thin-film structure would be directly transferred to a 3-d geometry model, an enormous number of finite elements would be created, as the smallest structure size determines the mesh density. Averaging the structural information and properties over the different layers in the cross section of the membrane is a good method to avoid such problems. The membrane is, therefore, initially treated as a quasi-two-dimensional object. 

As an additional example of high practical significance, we refer here to copper depKJsits when used in microelectronics, mirrors, and other optical applications. Those deposits have been observed to soften in time even when stored at room temperature for only 4 to 6 weeks. Also, mirrors and other precision objects made of copper will undergo surface deformation after a few months. This type of degradation can be counterbalanced by a suitable metal overcoating. Another, not always practical way is heat treatment to about 300°C. These phenomena are the direct results of microstructural instabilities, often referred to as recrystallization in the copper. It is worth stressing that recrystallization is not limited to copper (5). 

The factors that control the strictly alternating copolymer chain with no detectable errors (e. g., microstructures involving double insertion of ethene) have been the object of detailed studies since the discovery of the first Pd" catalysts for the alternating alkene/CO copolymerisation [11]. Sen was the first to demonstrate that double carbonylation is thermodynamically unfavorable and to suggest that the higher binding affinity of Pd" for CO relative to ethene inhibits multiple ethene insertions, even in the presence of very low concentrations of CO [12]. Therefore, once a palladium alkyl is formed, CO coordination ensures that the next monomer will be a CO molecule to generate the acyl complex. 

Polarized light microscopy is the study of the microstructures of objects using their interactions with polarized light [1,2,23-27,31-33]. The method is widely applicable to polymers [34] and to liquid crystals [34-37]. The polarizing micro-... 

Our objective in this chapter is to establish the quantitative connections between interparticle forces and colloid stability. Before we consider this it is instructive to look at the role of interaction forces in a larger context, that is, the relation between interparticle forces and the microstructure of dispersions and the factors that determine such a relation. These aid us in appreciating the underlying theme of this chapter, namely, the manipulation of interparticle forces to control the properties of dispersions. 

SOL-GEL TECHNOLOGY. The goal of sol-gel technology is lo use low temperature chemical processes to produce net-shape, net-surfacc objects, films, fibers, particulates, or composites that can be used commercially after a minimum of additional processing steps. See also Thin Films. Sol-gel processing can provide control of microstructures in the nanometer size range, i.e 1-100 nm (0.001-0.1 pm), which approaches the molecular level These materials often have unique physical and chemical characteristics. See also Nanotechnology (Molecular). 

Z-series images allow samples to be studied at different depths, and thus provide information about the three-dimensional distribution of solids and liquid. The number of fields (z series) that can be viewed depends on pinhole position, objective, and sample brightness. Fewer planes can be observed in darker samples. Images taken at steps of 3pm are needed to obtain a three dimensional representation of the microstructure. 

The objective of this work was to study the reaction conditions and microstructural properties of the products obtained in the Ti-N and Ti-C-N systems when combustion is carried out under a nitrogen pressure range 0.1-1.4 MPa. 

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