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排序方式: 共有275条查询结果,搜索用时 354 毫秒
31.
Taryn Jane Bond-Barnard Herman Steyn Inger Fabris-Rotelli 《International Journal of Project Management》2013
Call centres are increasingly being utilised in public sector programmes to facilitate and manage communication between numerous stakeholders. Yet, the impact of call centres on projects has not been investigated. This paper reports on a survey with 92 respondents that assessed the impact of a call centre for a repair and maintenance programme. An empirically verified model is presented to illustrate the relationship between call centre communication and project performance. A balance of frequent informal and formal communication is shown to reduce mistrust and conflict of interest resulting from each party trying to maximise his respective economic position in the principal–agency relationship. The data provides evidence that a call centre improves the communication, collaboration and trust in project principal–agency relationships which, in turn, is perceived to contribute to project performance. 相似文献
32.
Monica H Carlsen Inger TL Lillegaard Anette Karlsen Rune Blomhoff Christian A Drevon Lene F Andersen 《Nutrition journal》2010,9(1):37
Background
We have developed a food frequency questionnaire (FFQ) for the assessment of habitual diet, with special focus on the intake of fruit, vegetables and other antioxidant-rich foods and beverages. The aim of the present study was to evaluate the relative validity of the intakes of energy, food and nutrients from the FFQ. 相似文献33.
Standard forms of nonlinear microscopy rely on single beam scanning, but the usually weaker signal and the need to image in real-time call for parallelization of the image formation. Since the nonlinear susceptibilities necessitate a comparatively large illumination power, with current laser systems the brightness or field of view of any parallelized nonlinear microscope is limited by the brightness of the laser. For example, by producing an array of high aperture foci, multifocal multiphoton microscopy (MMM) provides real-time, light-efficient three-dimensional fluorescence imaging at high-resolution. The available power limits the degree of parallelization and hence codetermines the field of view. As the utilization of all the laser power is imperative, the focal intensity can be adjusted only through altering the number of foci. This compromises to some extent the flexibility to adjust the focal intensity to benign and effective levels. Here we introduce space-multiplexing (SMX) as a novel option in parallelized nonlinear microscopy, which enables an improved exploitation of the total laser power and facilitates changing the intensity levels in selected regions, without attenuating the total laser power. The basic idea of SMX is to overlap arrays of slightly offset coherent focal fields whose interference modulates the intensity across the sample. For a given degree of parallelization and power, SMX increases the two- and three-photon excited signal of parallelized nonlinear microscopy by a factor of up to 1.5 and 2.5, respectively. To some extent, sensitive regions may be spared out, whereas in regions with weaker nonlinear susceptibilities the intensity is increased. SMX is relevant to all modes of nonlinear microscopy, including parallelized second- and third-harmonic imaging, coherent anti-Stokes Raman scattering, and widefield multiphoton excitation. 相似文献
34.
35.
Inger Krantz 《Tunnelling and Underground Space Technology incorporating Trenchless Technology Research》1990,5(4):367-373
From an international perspective, Sweden enjoys a leading position concerning urban infrastructure as the industrialized world is struggling with similar problems. In many countries, the situation is critical. By taking advantage of the short channels of communication between the central and the local governmental bodies, researchers and industry in Sweden can develop knowledge of interest to the entire international community. This feature article combines four essays by leading Swedish experts in the field of infrastructure development. 相似文献
36.
Peter L Andresen F.Peter Ford 《International Journal of Pressure Vessels and Piping》1994,59(1-3):61-70
An approach for improved design and lifetime evaluation of environmental cracking is presented based on fundamental modeling of the underlying processes operative in crack advance. In outlining this approach and its application in energy industries, the requirements for a life prediction methodology will be highlighted and the shortcomings of the existing design and lifetime evaluation codes will be discussed. Examples will be given of its use in a variety of cracking systems, such as stainless steels and nickel alloys in hot water, and irradiation assisted stress corrosion cracking. 相似文献
37.
Andresen H Nikolov SI Jensen JA 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2011,58(5):935-943
This paper describes the application of 3-D synthetic aperture focusing (SAF) to a single-element trans-rectal ultrasound transducer. The transducer samples a 3-D volume by simultaneous rotation and translation, giving a helical motion. Two different 3-D SAF methods are investigated, a direct and a two-step approach. Both methods perform almost identically for simulated scatterers and give a significant improvement in azimuth resolution and a constant resolution in elevation. Side lobes below -60 dB are achievable for both methods. Validation of the method is achieved by scanning a simple wire phantom and a complex phantom containing wires in azimuth and elevation. The simple wire phantom shows the same results as that found through simulation. The complex phantom shows simultaneous focusing in azimuth and elevation for the wire scatterers. Consideration of the processing requirements for both 3-D SAF methods shows that the two-step approach can give equivalent performance using an order of magnitude fewer calculations. This reduction requires a temporary storage of 9.1 GB of data for the investigated setup. 相似文献
38.
P. L. Andresen G. M. Gordon S. C. Lu 《JOM Journal of the Minerals, Metals and Materials Society》2005,57(1):27-30
A stress-corrosion cracking (SCC) model has been adapted for performance prediction of high-level radioactive-waste packages
to be placed in the proposed Yucca Mountain repository. For these waste packages, the outer barrier material is the highly
corrosion-resistant alloy UNS-N06022 (alloy 22). The tensile stress is principally from weld-induced residual stress. To account
for crack propagation, the slip dissolution/film rupture (SDFR) model is adopted to provide mathematical formulae for prediction
of the crack growth rate. Once the crack growth rate at an initiated SCC is determined, it can be used to determine the time
to through-wall penetration for the waste package. This paper presents the development of the SDFR crack growth rate model.
A seismic-damage-related SCC crack opening area density model is also briefly described.
For more information, contact P.L. Andresen, GE Global Research, One Research Circle Schenectady, NY 12309; e-mail: andresen@crd.ge.com. 相似文献
39.
Dr.-Ing. K. Andresen 《Acta Mechanica》1973,17(3-4):291-303
Zusammenfassung Das Stauchen einfacher axialsymmetrischer Proben wird mit Hilfe des Verfahrens von der oberen Schranke untersucht. Die angegebene numerische Methode, ein iteratives Ritz-Verfahren für mehrparametrige Ansatzfunktionen, liefert bessere Schranken für die Stauchkraft als vergleichbare Verfahren in der Literatur. Zudem erhält man eine gute Approximation des momentanen Geschwindigkeitsfeldes und kann damit den Verlauf der Umformung schrittweise verfolgen. Das angegebene Verfahren läßt sich durch Wahl geeigneter Ansatzfunktionen sinnvoll auf andere Umformprozesse anwenden.
Mit 7 Abbildungen 相似文献
Numerical Evaluation of an Upper Bound Theorem with Application to Axisymmetric Compression
Summary The compression of simple axisymmetric specimen is treated by means of the upper bound theorem. An iterative Ritz-method, proposed in this paper, yields better upper bound loads than comparable methods known in literature. Moreover, a good approximation of the instantaneous velocity field is derived. Using this field the non-stationary deformation is examined step by step. By choosing a proper system of functions for the velocity field the given method well applies to other forming processes.
Mit 7 Abbildungen 相似文献
40.
Klaus Andresen 《国际钢铁研究》1975,46(9):571-574
Anwendung eines verallgemeinerten Schrankenverfahrens für starrplastische Umformung mit der Methode der finiten Elemente auf das Kegelstauchen. Bestimmung des Stauchdruckes in Abhängigkeit von der Geometrie und von der Werkstoffeigenschaft und Vergleich mit Versuchsergebnissen. 相似文献