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61.
h –p–adaptive projection with respect to any prescribed threshold value for the visual error. This projection can then be processed
by various local rendering methods, e.g. color coding of data or isosurface extraction. Especially for color coding purposes
modern texture capabilities are used to directly render higher polynomial data by superposition of polynomial basis function
textures and final color look-up tables. Numerical experiments from CFD clearly demonstrate the applicability and efficiency
of our approach.
Received September 25, 2001; revised March 31, 2003
Published online: May 26, 2003
The authors acknowledge the valuable hints of the anonymous referees. 相似文献
62.
TMS320C3X处理器具有两个双向各自相互独立的串行口。本文介绍了一种TMS320C30处理器与PC机串行口实现异步双向通讯的方式及实现方法。实际应用证明该方法具有很高的实用性和可靠性。 相似文献
63.
The aim of magnetization transfer is to saturate the protons of the macromolecule pool with a radiofrequency (RF) pulse leading
to differences in free water pool signal. Magnetization transfer (MT) contrast is difficult to achieve with the echo planar
imaging (EPI) technique, although its short acquisition time would be most beneficial. Indeed, the RF saturation pulses can
only be applied once before sampling the whole k-space in a single-short sequence. A possible solution to improve the sensitivity
of EPI to magnetization transfer consists in applying a train of several saturation RF pulses before image acquisition. The
different parameters of a RF pulse train and their influence on the MT rate have been tested to optimize an EPI clinical sequence.
Our experimental procedure makes it possible to obtain a MT map in about 1 second. The technique is evaluated by multiple
sclerosis lesion characterization.
Supported by grants from the French research ministry and Siemens medical France. 相似文献
64.
Direct Segmentation of Algebraic Models for Reverse Engineering 总被引:1,自引:0,他引:1
In Reverse Engineering a physical object is digitally reconstructed from a set of boundary points. In the segmentation phase these points are grouped into subsets to facilitate consecutive steps as surface fitting. In this paper we present a segmentation method with subsequent classification of simple algebraic surfaces. Our method is direct in the sense that it operates directly on the point set in contrast to other approaches that are based on a triangulation of the data set. The segmentation process involves a fast algorithm for k-nearest neighbors search and an estimation of first and second order surface properties. The first order segmentation, that is based on normal vectors, provides an initial subdivision of the surface and detects sharp edges as well as flat or highly curved areas. One of the main features of our method is to proceed by alternating the steps of segmentation and normal vector estimation. The second order segmentation subdivides the surface according to principal curvatures and provides a sufficient foundation for the classification of simple algebraic surfaces. If the boundary of the original object contains such surfaces the segmentation is optimized based on the result of a surface fitting procedure. 相似文献
65.
Bouc-Wen model parameter identification for a MR fluid damper using computationally efficient GA 总被引:1,自引:0,他引:1
A non-symmetrical Bouc-Wen model is proposed in this paper for magnetorheological (MR) fluid dampers. The model considers the effect of non-symmetrical hysteresis which has not been taken into account in the original Bouc-Wen model. The model parameters are identified with a Genetic Algorithm (GA) using its flexibility in identification of complex dynamics. The computational efficiency of the proposed GA is improved with the absorption of the selection stage into the crossover and mutation operations. Crossover and mutation are also made adaptive to the fitness values such that their probabilities need not be user-specified. Instead of using a sufficiently number of generations or a pre-determined fitness value, the algorithm termination criterion is formulated on the basis of a statistical hypothesis test, thus enhancing the performance of the parameter identification. Experimental test data of the damper displacement and force are used to verify the proposed approach with satisfactory parameter identification results. 相似文献
66.
介绍了以DSPIC30F6014单片机为核心控制器进行信号检测,并通过执行机构对设备实现控制.系统采用PC总线方式连接新型的CMOS集成温湿度传感器,同时控制CAN总线控制器和总线收发器MCP2551构成的总线通信系统进行数据传输,通过PCI-CAN适配卡将上位机与控制网络连接起来,完成核医疗设备的分布式测控系统设计.详细介绍了系统构成、部分软硬件设计方法等. 相似文献
67.
68.
金属橡胶/硅橡胶复合阻尼材料疲劳性能研究 总被引:3,自引:1,他引:3
探讨金属橡胶/硅橡胶复合阻尼材料的疲劳性能,结果表明:复合硅橡胶显著提高金属橡胶的刚度;以软特性段刚度下降5.0%为疲劳判据,测试出其位移-疲劳寿命曲线。 相似文献
69.
70.
介绍了JY6607PAG淬火介质特性,测定了不同浓度了JY6607PAG冷却特性曲线。选择不同浓度的JY6607PAG淬火介质及传统水或油淬火介质对45钢、30CrMo和1Cr13试棒进行淬火,分析了拉伸性能、淬透性、淬火硬度均匀性及淬火开裂倾向。结果表明,45钢采用5%--10%JY6607PAG淬火、30CrMo钢采用10%--15%JY6607PAG淬火可以获得比传统淬火介质水或油更好的综合性能。试验所采用的所有浓度的JY6607PAG淬火介质都能淬透1Cr13不锈钢,但是,浓度低于20%时,出现了淬火开裂。因此,使用时建议采用高于30%的浓度。 相似文献