Results 1 - 10 of 1987
Results 1 - 10 of 1987. Search took: 0.044 seconds
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[en] Numerical computer calculations are used to explore the design characteristics of a concave electrostatic electron mirror for a mirror attachment for a conventional scanning electron microscope or an instrument designed totally as a scanning electron mirror microscope. The electron paths of a number of set-ups are calculated and drawn graphically in order to find the optimum shape and dimensions of the mirror geometry. This optimum configuration turns out to be the transition configuration between two cases of electron path deflection, towards the optical axis of the system and away from it. (Author)
[en] The Atomic Resolution Microscope (ARM) is one of two unique high voltage electron microscopes at the Lawrence Berkeley Laboratory's National Center for Electron Microscopy (NCEM). The latest results from this new instrument which was manufactured by JEOL, Ltd. to the performance specifications of the NCEM, delivered in January of 1983, and soon to be open to access by the entire microscopy community are given. Details of its history and development are given and its performance specifications are reviewed
[en] The purpose of the study was to investigate the effects of the single and fractionated irradiation on the microvasculature of the rat submandibular gland in rats. For this study, 90 Sprague-Dawley strain rats were irradiated to their neck region with equal split doses of 9 Gy for a 4 hours interval and 15 Gy single dose by 6 MV X-irradiation and sacrificed on the 1st, 3rd, 7th, 14th and 27th day after irradiation. The author observed histological changes at Hematoxylin and Eosin staining and PAS staining under a light microscope, and also observed distribution and structural changes of the microvasculature in rat submandibular gland using a scanning electron microscope by forming vascular resin casting. The results were as follows: 1. In the light microscopic examination, the microvasculature was slightly diated and decreased in number on the 1st day after irradiation, and increase in number of microvasculatere was observed on the 3rd day after irradiation. And then distribution of microvasculature was markedly increased on the 7th day after irradiation, but decreased on the 14th day after irradiation again. Such changes were greater in the single irradiated group than in the fractionated irradiated group. 2. The reaction to PAS staining on glandular cell was decreased on the 1st and the 3rd day after irradiation, and recovered on the 7th day after irradiation. The reaction was decreased on the 14th day after irradiation again, and recovered on the 28th day after irradiation. Changes were more apparent in the single irradiated group. 3. In the scanning electron microscopic examination, early changes of microvasculature were decreased capillary density, dilation of conduits and meandering. Increased capillary density or anastomosis due to vascular reproduction and smooth curved running were observed on the 7th and 14th day after irradiation. Decreased capillary and smooth running tendency were observed on the 28th day after irradiation again. Such changes were greater in the single irradiated group than in the fractionated irradiated group.
[en] Phenol–formaldehyde microcapsules containing solvent and epoxy resin are successfully prepared via in situ polymerization. Resin–solvent capsules are produced in high yield (up to 82.33%) and high core content (up to 86.3%), of which the diameter distribution ranges between 51 and 323 μm depending on the agitation rate varying from 400 to 1200 rpm. Chemical structure of the capsules is studied by FTIR, and surface morphology is further characterized by optical and electron microscopes. It is found that the capsules possess a rough and compact shell. Meanwhile, encapsulated core materials still keep sufficiently high chemical reactivity, and healing efficiencies effectively exceed 100% with the addition of 20 wt% microcapsules in the host polymer matrix.