Scanning electron production

Scanning electron beam systems are available commercially, and are commonly used for mask generation. Electron projection systems are also used to obtain resolution over a large field. Current cathode sources have a short lifetime, limiting use in production processes. 

This paper summarises an initial feasibility on reeyling scrap automotive plasties and eomposites using a eatalytie conversion process. The eharaeterisationofhydroearbon products is presented for sheet moulding compound (SMC), auto shredder residue (ASR) and reinforeed polypropylene (R-PP) materials and mixtures of body panels. Gas chromatography and scanning electron microscopy is used for the material characterisation. 26 refs. 

The explanted devices were also examined by scanning electron microscopy and the results shown in Fig. 21 (18). The pictures clearly show a progressive diminution of a central uneroded zone and the development of voids around the periphery of the rod-shaped device. The presence of voids suggest that once erosion starts, generation of hydrophilic degradation products at that location accelerates further polymer hydrolysis. 

A Dektak siuface profilometer was used to measure the etch rates. The profiles of the etched films were observed by field emission scanning electron microscopy (FESEM). In addition, x-ray photoelectron spectroscopy PCPS) was utilized to examine the existence of possible etch products or redeposited materials, and to elucidate the etch mechanism of Co2MnSi magnetic films in a CVOa/Ar plasma. 

Fig. 4a,b. Scanning electron micrographs of the crystalline products a in the presence of PAMA dendrimer (G=1.5) b in the absence of PAMA dendrhner (G=1.5) (reproduced from [28]... 

Stratmann R, Lehner CF 1996 Separation of sister chromatids in mitosis requires the Drosophila pimples product, a protein degraded after the metaphase/anaphase transition. Cell 84 25-35 Sumner AT 1991 Scanning electron microscopy of mammalian chromosomes from prophase to telophase. Chromosoma 100 410-418... 

Scanning electron microscopy and other experimental methods indicate that the void spaces in a typical catalyst particle are not uniform in size, shape, or length. Moreover, they are often highly interconnected. Because of the complexities of most common pore structures, detailed mathematical descriptions of the void structure are not available. Moreover, because of other uncertainties involved in the design of catalytic reactors, the use of elaborate quantitative models of catalyst pore structures is not warranted. What is required, however, is a model that allows one to take into account the rates of diffusion of reactant and product species through the void spaces. Many of the models in common use simulate the void regions as cylindrical pores for such models a knowledge of the distribution of pore radii and the volumes associated therewith is required. 

In 1994, we reported the dispersion polymerization of MM A in supercritical C02 [103]. This work represents the first successful dispersion polymerization of a lipophilic monomer in a supercritical fluid continuous phase. In these experiments, we took advantage of the amphiphilic nature of the homopolymer PFOA to effect the polymerization of MMA to high conversions (>90%) and high degrees of polymerization (> 3000) in supercritical C02. These polymerizations were conducted in C02 at 65 °C and 207 bar, and AIBN or a fluorinated derivative of AIBN were employed as the initiators. The results from the AIBN initiated polymerizations are shown in Table 3. The spherical polymer particles which resulted from these dispersion polymerizations were isolated by simply venting the C02 from the reaction mixture. Scanning electron microscopy showed that the product consisted of spheres in the pm size range with a narrow particle size distribution (see Fig. 7). In contrast, reactions which were performed in the absence of PFOA resulted in relatively low conversion and molar masses. Moreover, the polymer which resulted from these precipitation... 

Fig. 1.42. Scanning electron-microscopic photographs of different freeze dried products.

Fig. 1.44. Scanning electron-microscopic photographs of a vial containing freeze dried trehalose solution, (a), collapsed product from the bottom of the product (b), shrunk product after 6 months of storage at +20 °C with a RM too high and stored at a too high a temperature (Fig. 6 from [ 1.29]).

Auger electron spectrometry (AES), reported by Auger in 1923 [40], is also a valuable technique for analysing surfaces. The technique is somewhat similar to ESCA, measuring electrons emitted from a surface as a result of electron bombardment. In both cases, the sampling depth is ca. 20A. Coupling this technique with scanning electron microscopy (SEM) produced a tandem (AES-SEM) technique which has proved extremely productive. 

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