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51.
52.
Ralph Schneider Wolfgang Marquardt 《Chemical engineering science》2002,57(10):1763-1792
Information technology has been becoming increasingly important in all areas of engineering during the last few years. Much of the progress achieved in chemical engineering would not have been possible without the enabling methods and tools provided by information technology. This trend will continue in the future but most likely with a considerably wider scope. While individual software tools and services have been in focus until recently, their integration into engineering work processes is an emerging and challenging area of research and development. This contribution attempts to highlight state of the art and future trends in supporting the activities during the life cycle of a chemical process by means of information technology. Emphasis will be largely on the process and plant design process rather than on procurement, manufacturing, and distribution of materials in the supply chain. 相似文献
53.
The common way to construct Voronoi tessellations is to compare the distances between given reference points using a given
distance function. To generalize this distance-function concept we expand an existing approach which defines distance functions
by their ``unit circles'. Our new approach allows modeling the ``unit circles' by a closed Spline curve. Changing the control
polygon directly affects the tessellation's appearance. Typically generalized Voronoi diagrams are represented by Voronoi
vertices and curves separating the individual tiles. To obtain interactive modeling we extended an existing hardware accelerated
rendering approach computing a bitmap-representation using different colors for individual tiles. With our extension, we are
able to use our Spline distance representations as input for a growing process. This growing process easily takes into account
weighting approaches like multiplicative, additive, and even free functional weighting. 相似文献
54.
55.
Decay of hollow atoms above and below a surface 总被引:1,自引:0,他引:1
56.
A multiparameter wearable physiologic monitoring system for space and terrestrial applications. 总被引:4,自引:0,他引:4
Carsten W Mundt Kevin N Montgomery Usen E Udoh Valerie N Barker Guillaume C Thonier Arnaud M Tellier Robert D Ricks Robert B Darling Yvonne D Cagle Nathalie A Cabrol Stephen J Ruoss Judith L Swain John W Hines Gregory T A Kovacs 《IEEE transactions on information technology in biomedicine》2005,9(3):382-391
A novel, unobtrusive and wearable, multiparameter ambulatory physiologic monitoring system for space and terrestrial applications, termed LifeGuard, is presented. The core element is a wearable monitor, the crew physiologic observation device (CPOD), that provides the capability to continuously record two standard electrocardiogram leads, respiration rate via impedance plethysmography, heart rate, hemoglobin oxygen saturation, ambient or body temperature, three axes of acceleration, and blood pressure. These parameters can be digitally recorded with high fidelity over a 9-h period with precise time stamps and user-defined event markers. Data can be continuously streamed to a base station using a built-in Bluetooth RF link or stored in 32 MB of on-board flash memory and downloaded to a personal computer using a serial port. The device is powered by two AAA batteries. The design, laboratory, and field testing of the wearable monitors are described. 相似文献
57.
The k-nearest-neighbour (kNN) algorithm is widely applied for the estimation of forest attributes using remote sensing data. It requires a large amount of reference data to achieve satisfactory results. Usually, the number of available reference plots for the kNN-prediction is limited by the size of the area covered by a terrestrial reference inventory and remotely sensed imagery collected from one overflight. The applicability of kNN could be enhanced if adjacent images of different acquisition dates could be used in the same estimation procedure. Relative radiometric calibration is a prerequisite for this. This study focuses on two empirical calibration methods. They are tested on adjacent LANDSAT TM scenes in Austria. The first, quite conventional one is based on radiometric control points in the overlap area of two images and on the determination of transformation parameters by linear regression. The other, recently developed method exploits the kNN-cross-validation procedure. Performance and applicability of both methods as well as the impact of phenology are discussed. 相似文献
58.
OBJECTIVE: Hyaluronate degradation was analyzed in cultures of healthy tissue and tissue obtained from patients with rheumatoid arthritis. METHODS: Arthritic and healthy synovial tissues were incubated in culture with [3H]glucosamine. Labelled hyaluronate was extracted and its size determined by gel filtration. The production of low molecular weight hyaluronate was analyzed by pulse-chase experiments. Radical production was measured by a cytochrome C reduction assay. RESULTS: Healthy tissues and some arthritic tissues that did not contain significant amounts of granulocytes produced high molecular weight hyaluronate. In contrast, arthritic tissue infiltrated with granulocytes released low molecular weight hyaluronate. Pulse-chase experiments suggested that hyaluronate was degraded in these arthritic tissues. Exogenous hyaluronate was degraded only by intact tissue, but not by cells in culture obtained from synovial membranes of synovial fluids. Hyaluronate degradation was accompanied by massive oxygen radical production. Radical scavengers protected hyaluronate from degradation in synovial tissue. Some protection was achieved by superoxide and catalase or by methionine and complete protection by the iron chelators diethyltriaminepentacetic acid or deferoxamine mesylate. CONCLUSION: Degradation of hyaluronate in arthritic synovial tissue may be inhibited in tissue culture by radical scavengers. 相似文献
59.
Many problems in electromagnetics involve modeling a changing multi-dimensional field, and one can often gain insight into the underlying physical problem by animating the changes. The ability to view directly the evolving field may also provide a useful debugging tool during modeling and simulation. Here, we present a relatively simple scheme to animate a changing two-dimensional field (in this case EM wave propagation is considered in particular). The scheme permits various mappings of field values to colors, so that the color of each pixel in an image indicates the field found at the corresponding location within the computational domain. Alternatively, a gray-scale mapping can be used. A program used to construct individual frames of the animation is presented in full. Sufficient detail is given so that the customization of the code is straightforward. Public-domain software is used to view the frames as an animated sequence, or to generate an MPEG file. Some aspects of the scheme described here are tailored for use in an X-Windows or UNIX environment, but most of the important steps are independent of the operating system. Frame-generation routines are presented in FORTRAN (C versions of the code are similar and can be obtained “on-line”). The scheme presented here is relatively fast, efficient, and flexible, and should serve well as a starting point for those wanting to “roll their own” graphics. In addition, for those needing more sophisticated renderings, pointers are given to several powerful commercial and public-domain graphics packages 相似文献
60.
The synthesis of monodisperse hard segments containg 2,4-TDI and 1,4-butanediol by a simple technique is described. High purity material is obtained in good yield. The structures of these hard segments are confirmed by proton n.m.r., 13Cn.m.r., and i.r. Glass transition temperatures and melting temperatures are reported. The Tg′s of the hard segments are inversely proportional to the reciprocal of their molecular weights. The Tm′s show an odd-even effect relative to the number of 2,4-TDI units in the hard segment. 相似文献