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131.
132.
汽车自动传动液的研制 总被引:2,自引:0,他引:2
介绍了自动传统液的分类规格、自动传动液的特性和相关的评定方法;研制了无锌和低锌配方的两种产品,经评定试验和实机使用,符合DexronⅡD、Mercon和AllisonC-4的规格要求,达到了国外同类产品的质量水平。 相似文献
133.
Due to the unique requirements of a series of projects to specify communications architectures using graphical representations (Cara and MFD), we have developed the communications-oriented rule-based language Carla (Cara Rule Language), which provides an executable specification of the architecture being developed. Carla is designed to provide the ability to specify and simulate high-level, possibly incomplete, specifications of communications architectures, and to allow the developer to refine the specification through the addition of behavior-describing rules. Carla is also well-suited to creating black-box specifications of any system whose behavior depends on input/output history. We describe the features of the language, discuss various design issues, and provide examples of various communications protocols specified in Carla. 相似文献
134.
135.
The purpose of this work is to characterize the sky relative radiance and luminance distributions from the analysis of sky images acquired using a monochromatic CCD wide angle lens camera. The proposed methodology is based on the reduction of the number of the gray levels from the original image, in order to sharpen the different regions of the sky hemisphere, resulting in low level gray scale maps. In these maps each gray level is related to an intensity level and each pixel is associated to a sky direction. An experimental system that is able to simultaneously supply images from the sky and solar irradiance data was developed using a commercial CCD camera. The sky relative radiance and luminance distributions for different sky conditions were also determined. The resultant maps agree with observations of the main characteristics of sky radiance and luminance distributions. 相似文献
136.
通过对TN S系统接地方式中重复接地的探讨 ,介绍了重复接地对N线和PE线的不同作用 ,明确了TN S系统接地方式中重复接地的设计和施工方法。 相似文献
137.
长输管道工程是以线路管道与沿途站场为主要内容的建设工程,其物资配送有着不同于一般物流管理的特点,点多线长,且交通不便.文章结合西南成品油管道建设工程的物资配送实践,总结出长输管道物资配送的类型,并从机构设置、计划编制、台账和报表管理等方面介绍了物资配送的管理内容及经验,实践证明,这种物资配送方法不但使业主的物资管理人员大为减少,而且使长输管道工程的物资供应更加及时有序. 相似文献
138.
B. Bary 《Cement and Concrete Research》2006,36(11):2061-2073
In this paper, the porosity of cementitious materials is described in terms of pore size distribution by means of a 3-dimensional overlapping sphere system with polydispersivity in size. On the basis of results established by Lu and Torquato [B. Lu, S. Torquato, Nearest-surface distribution functions for polydispersed particle systems, Phys. Rev. A 45(8) (1992) 5530-5544] and Torquato [S. Torquato, Random Heterogeneous Media: Microstructure and Macroscopic Properties. Springer-Verlag: New York, 2001] providing relations for nearest-neighbor distribution functions, the volume fraction of pores having a radius larger than a prescribed value is explicitly expressed. By adopting an appropriate size distribution function for the sphere system, it is shown that the pore size distribution of cementitious materials as detected for instance by mercury intrusion porosimetry (MIP), which generally points out several pore classes, can be well approached. On the basis of this porosity representation, the evaluation of the capillary pressure in function of the saturation degree is provided. The model is then applied to the simulation of the saturation degree versus relative humidity adsorption curves. The impact of the pore size distribution, the temperature and the thickness of the adsorbed water layer on these parameters are assessed and analyzed for three model materials having different pore characteristics. 相似文献
139.
压裂泵往复密封性能及机理研究 总被引:2,自引:1,他引:1
根据流体动压润滑理论,对压裂泵柱塞密封摩擦副的润滑机理进行了理论分析。在排出和吸入行程,柱塞密封摩擦副均能满足流体动压润滑的条件,即在柱塞与密封界面上能形成并保持一定厚度的油膜润滑密封,从而达到减小摩擦提高寿命的目的;建立了摩擦界面油膜厚度和泄漏量的计算公式。利用有限元法理论,对密封圈的压力沿轴向的分布规律、泄漏量与压力变化关系进行了模拟计算。对往复密封圈沿轴向压力分布、泄漏量随压力变化进行了测试;试验结果表明,建立的计算模型具有较高的计算精度,揭示了压裂泵的密封机理。 相似文献
140.
Claus Bahlmann Author Vitae 《Pattern recognition》2006,39(1):115-125
The selection of valuable features is crucial in pattern recognition. In this paper we deal with the issue that part of features originate from directional instead of common linear data. Both for directional and linear data a theory for a statistical modeling exists. However, none of these theories gives an integrated solution to problems, where linear and directional variables are to be combined in a single, multivariate probability density function. We describe a general approach for a unified statistical modeling, given the constraint that variances of the circular variables are small. The method is practically evaluated in the context of our online handwriting recognition system frog on hand and the so-called tangent slope angle feature. Recognition results are compared with two alternative modeling approaches. The proposed solution gives significant improvements in recognition accuracy, computational speed and memory requirements. 相似文献