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1.
Detector physics and simulation of resistive plate chambers 总被引:1,自引:0,他引:1
Werner Riegler Christian Lippmann Rob Veenhof 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2003,500(1-3):144-162
We present a simulation model suited to study efficiency, timing and pulse-height spectra of Resistive Plate Chambers. After discussing the details of primary ionisation, avalanche multiplication, signal induction and frontend electronics, we apply the model to timing RPCs with time resolution down to 50 ps and trigger RPCs with time resolution of about 1 ns. 相似文献
2.
Predicting Forest Age Classes from High Spatial Resolution Remotely Sensed Imagery Using Voronoi Polygon Aggregation 总被引:1,自引:0,他引:1
Efficient identification of forest age is useful for forest management and ecological applications. Here we propose a user-assisted method for determining forest age using high spatial resolution remotely sensed imagery. This method requires individual trees to be extracted from imagery and represented as points. We use a local maximum filter to generate points that are converted to Voronoi polygons. Properties of the Voronoi polygons are correlated with forest age and used to aggregate points (trees) into areas (stands) based on three forest age classes. Accuracy of the aggregation ranges from approximately 68% to 78% and identification of the mature class is more consistent and accurate than the younger classes. 相似文献
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The author relates his experiences in a small software development company. These experiences show that project management is challenging and if the project manager is an obstacle, the project is bound to fail. When it does, it can spell disaster for the manager and anyone who accompanies him or her on a software development journey. 相似文献
5.
This article is a brief summary of the Discussion session held after the presentation of the preceding papers at the conference organized by the Industrial Carbon and Graphite Group of the Society of Chemical Industry, London, March 1984. 相似文献
6.
This report describes the results of a survey completed in December 1988 on the production and employment of PhDs and faculty in PhD-granting computer science/engineering departments during the 1987-8 academic year. All 127 computer science (CS) departments (115 US and 12 Canadian) participated. In addition, 34 departments offering the PhD in computer engineering (CE) were included. Throughout the report. CE statistics are reported separately so that comparisons with previous years can be made for CS. The intent is to merge all statistics for CS and CE after several years 相似文献
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Aard J. Groen Petra C. De WeerdNederhof Inge C. Kerssensvan Drongelen Rob A.J. Badoux Gerard P.H. Olthuis 《Creativity & Innovation Management》2002,11(1):2-16
In this paper we describe a framework for analysing the creation and justification of Research & Development. The 4S framework is developed for analysing the scope, scale, skills and social network aspects of Research & Development value. The framework is based on social system theory, a process contingency model, and recent Research & Development metrics. We present a first empirical assessment based on a workshop using the 4S framework for leveraging Research & Development. Results that assist in the assessment of value creation utilising R & D within networks are very relevant in high tech industries. The multi–dimensional process approach of this framework seems promising for understanding and managing R&D value creation, but needs further operationalisation. Case studies are described and a Dutch network on leveraging R&D has been initiated. 相似文献
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W. W. Gerberich H. Huang W. Zielinski P. G. Marsh 《Metallurgical and Materials Transactions A》1993,24(3):535-543
An interconnected set of observations assesses current equilibrium models of the ductile-brittle-transition temperature (DBTT).
This involvesin situ transmission electron microscopy (TEM) studies of crack-tip dislocations in single and polycrystals and bulk fracture toughness
tests at various temperatures. Beyond KI values of 8 MPa · m1/2 in both iron-base single and polycrystals, large numbers of redundant dislocations are created, as postulated recently by
Weertman. [38] Still, the necessary shielding dislocations, as required by equilibrium, can be detected at values as high
as 20 and 40 MPa · m1/2 byex situ TEM and electron channeling, respectively. In addition, the close approach of dislocations to the crack tip in some of the
studies, as opposed to others, suggests that large dislocation free zones (DFZ) are a thin-film artifact. However, a failure
criterion based partly on the Rice-Thomson model’21 is both consistent with the absence of a large DFZ and observed fracture
toughness variations with test temperature. It is emphasized that this toughness transition is entirely in the semibrittle
regime where cleavage is the failure mode. Nevertheless,K
lc values increase from 3 to 60 MPa·m1/2 with an increase in test temperature.
This article is based on a presentation made in the symposium “Quasi-Brittle Fracture” presented during the TMS fall meeting,
Cincinnati, OH, October 21–24, 1991, under the auspices of the TMS Mechanical Metallurgy Committee and the ASM/MSD Flow and
Fracture Committee. 相似文献