An application of interactive analysis and computer graphics in stochastic modeling

This paper will describe the application of an interactive queueing network analyzer and an interactive graphics system to the analysis of a multiple processor computer system. The application of these tools greatly increased the productivity of the modelers and resulted in insights which would have otherwise been difficult, if not impossible, to obtain. With this experience as background, we discuss how the increasing availability of computing resources, especially high resolution interactive computer graphics and sophisticated modeling packages, is likely to have a profound influence on the applied stochastic modeler.     

Observation-point-dependent blocking shadows on a reflector antenna

The authors present efficient algorithms that can be incorporated in a physical-optics integration to account for migrating feed- and observation-point-dependent geometrical shadows caused by obstacles in the aperture of a reflector antenna with the feed under focused or scanned conditions. The expressions involve only addition and multiplication of simple low-order polynomials and hence do not introduce expensive overhead into the numerical integration. Obstacle shapes considered are disks, polygons, cylinders, and polyhedrons. Some appropriate diffraction corrections are presented which are compatible with the blocking algorithms     

Indium- and zinc-mediated allylation of difluoroacetyltrialkylsilanes in aqueous media

Metal-mediated allylations of difluoroacetyltriakylsilanes with various allyl bromides in aqueous media form homoallylic alcohols exclusively. The common Brook rearrangement, carbon to oxygen-silyl migration, is totally suppressed with no detectable formation of silyl enol ether. Influence of solvents on reaction is studied. Reactivity differences between indium and zinc are also described.     

High-power single-mode 2.0 μm laser diodes

Data are presented on high-power single-mode index-guided laser diodes fabricated from a strained-layer InGaAs-InGaAsP double quantum well heterostructure epitaxial design. The total maximum power and external efficiency achieved are 50 mW and 43%, respectively. The far-field is measured to be 31° by 46° in the parallel and perpendicular directions, yielding an aspect ratio of 1.5 for the single-mode laser diode. The optical output of the laser diode is a multi-longitudinal mode spectrum spanning 1.98-2.00 μm at an output power of 50 mW CW. The characteristic temperature of the laser diode is 48 K     

Training needs for chemists in nuclear medicine research and production

The field Nuclear Medicine has expanded rapidly over the last two decades. Individuals with training in radiochemistry are needed in industry, medical centers and hospitals. Although basic training in organic chemistry, inorganic chemistry, biochemistry or pharmacy are required, radiochemistry knowledge is essential for all of these individuals. Opportunities and training requirements in these areas will be discussed.