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11.
A laser collimator is necessary for testing and verification of the pointing, acquisition and tracking (PAT) performance of inter-satellite laser communication terminals on the ground. The laser collimator must have a large clear aperture to fit the PAT performance testing system. The PAT subsystem has a large field of view for the acquisition and a high angular accuracy for the fine tracking. To resolve the conflict between large field of view and fine angular resolution, a large-aperture double-focus laser collimator is proposed and its optical design and mechanical structure are described. The collimator mainly consists of a primary lens, a reflector, a beam-splitting plate, a secondary lens, two compensating lenses, two imaging sensors and a laser. The primary lens directly forms the long focal length arm of the collimator. The combination of the primary lens and the secondary lens form the short focal length arm of the collimator. The collimator has an angular resolution <0.75 μrad and a 10 mrad field of view. For the collimator, the incident beam is focused on the two imaging sensors by its two arms, and the beam emitted from the laser is collimated and transmitted. The collimator is combined with an optical scanner and a fine beam deflector to test and verify the PAT performance of the inter-satellite laser communication terminal in a full physical manner. 相似文献
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Natural biomaterials have extensively been researched since their distinguished properties adapting to their living surroundings. The cuticle surfaces of bovine hoof and dung beetle directly contact soil when they move on soft ground or in soil. Their surface materials and structures can provide some information for designing soil-engaging components of soft terrain-machines. While, it is difficult to measure their mechanical properties since the cuticle of the bovine hoof wall and dung beetle are very thin. Nanoindenter provides a powerful tool for examining the mechanical properties such as reduced modulus and hardness in nano-scale. The testing methods for nanoindentation properties of the cuticle of the bovine hoof wall and dung beetle (Copris ochus Motschulsky) were discussed in this work. 相似文献
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Indrek S. Wichman Scott C. Morris Andrew W. McIntosh 《Experimental Thermal and Fluid Science》2002,25(8):595-603
A fire testing facility named the “MSU Fire Tunnel” has been developed. The intent was to devise a testing apparatus that controlled the flow of oxidizing gas in the tunnel to an extent not heretofore accomplished. A novel approach was developed for mounting the flame-spread samples flush with the surface of an “airfoil”. This method avoids previous complications of determining the exact position of the leading edge of the velocity boundary layer. Data were gathered for the flow field using hot-wire anemometry. These data indicated that a zero-pressure gradient Blasius boundary layer flow was established along the airfoil and fuel sample surfaces. Opposed-flow flame-spread tests were conducted and correlations were produced that support the predictive capacity of this apparatus. It was shown that the opposed flow flame-spread data allowed distinctions to be made between correlations of previous researchers. No such comparisons were formerly possible. A finite-chemistry correlation was shown to be consistent with, and similar to, correlations derived in the previous work. 相似文献
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The role of physical testing in product development is changing due to the requirements for faster new product development, reduced tolerance of failures in the field and the emergence of computer aided engineering (CAE) technologies. To be used most effectively, testing must be seen as an integral part of the process for reducing risks associated with new product introductions. Quality function deployment (QFD) and failure modes and effects analysis (FMEA) can be used to establish effective test and development plans that integrate the use of virtual and physical testing. By effectively integrating virtual and physical test technologies significant improvements in product performance can be achieved within shorter times and with reduced development and manufacturing costs. The approach was illustrated by a process of reducing in-cab noise during the design of a new truck. 相似文献
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Philippe Quevauviller 《Mikrochimica acta》1996,123(1-4):3-14
A great number of analyses is performed every year, the results of which are used for many purposes, e.g. the quality of goods and food, the status of quality of the environment or the health of patients. The accuracy of these results is a prerequisite for a good interpretation of the data obtained. One of the most powerful tool for achieving quality control of chemical analysis is to use reference materials (RMs) and certified reference materials (CRMs). These materials are necessary for one or more of the following items: method validation (CRMs), monitoring of the state of statistical control (RMs), samples in inter-comparisons (RMs), etc. The requirements and use of RMs and CRMs in chemical analysis are described, with special emphasis on environmental analysis, and some examples of environmental materials currently in production within the Standards, Measurements and Testing Programme (formerly BCR) of the European Commission are given. 相似文献
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