不断轨动态称量轨道衡安装导引

从轨道衡地点选定、线路要求、机械台而、电气设备等方面介绍不断轨动态称量轨道衡安装各阶段、过程的方法与指引，以及轨道衡的计量检定。     

Spatial fisheries ecology: Recent progress and future prospects

We review recent progresses made in the study of fish distribution and survival over space — i.e., fisheries spatial ecology. This is achieved by first surveying the most common statistical approaches and relative challenges associated with the analysis of fisheries spatial data, loosely grouped in geostatistical and regression approaches. Then we review a selected number of case-studies implementing the discussed techniques. We conclude by proposing new areas of statistical and ecological research to further our understanding of how fish distribute and survive in space. This review serves a dual purpose by emphasizing the scientific importance of studying spatial interactions to better understand the temporal dynamics of fish abundance, and by promoting the development of new analytical and ecological approaches for the analysis of spatial data. Through our survey we cover different statistical techniques, marine ecosystems and life stages. This analytical, geographic and ontogenetic variety is also purposely selected to highlight the importance of comparative and multidisciplinary studies across diverging ecological disciplines, ecosystems and life stages. Besides having a general ecological relevance this review also bears a more applied significance, owing to the increasing need for protecting renewable marine resources along with their primary habitat.     

LCD定标器X级图像缩放引擎的VLSI设计

LCD定标器的X级图像缩放引擎负责对输入图像进行水平方向的缩放．文中介绍了定标器的总体结构，以及实现X级图像缩放引擎的算法及其滤波器结构，并详细地阐述了X级图像缩放引擎硬件实现中的时序关系．     

船用柴油机排气消声器模型试验的相似原则

本文将相似理论Π定理应用于消声器的设计中，给出了五个相似准则。这些无量纲数考虑了在船用消声器小尺寸模型试验中消声器的声学、空气动力特性和几何尺度的相似性，并对相似准则中一些物理量进行了讨论。     

CO2 emissions in relation to street-network configuration and city size

The street-network efficiency of tens of British cities in relation to transport fuel consumption and CO₂ emissions are analyzed. The results show a strong linear positive correlation between length entropy and average street length, and a negative correlation between entropy and street density. Also, the results suggest that in a large city the street network is used more efficiently than in a small city, as indicated by the sublinear relations between city size (population) and the number of streets, total length of streets, and the area covered by the street network. The sublinear relation means that these parameters grow more slowly than the city size. By contrast, because a larger fraction of the street network is used at close to full capacity during considerable part of the time in a large city than a small one, the fuel consumption and the CO₂ emissions show a linear relation with city size and superlinear relation with total street length. The superlinear relation means that the CO₂ emissions increase faster than the total street length, a measure of the network size. Thus, large cities may be less energy efficient and environmentally friendly than small cities. In every city the street network needs to interconnect all the buildings, which requires a certain minimum size. In a small city, however, the network is used to a low capacity most of the time so that its relations to fuel consumption and the CO₂ emissions are more favorable than those in a large city.     

Intermittent turbulence and copepod dynamics: Increase in encounter rates through preferential concentration

Turbulence has a strong influence on plankton contact rate, which is a crucial parameter for plankton ecology. In the field of particle-turbulence interactions, it is now well known that fully developed turbulence does not always homogenise particle distributions, but instead creates, in some well-defined conditions, preferential concentrations of heavy particles. Many studies have considered the influence of this type of preferential concentration on particle contact rate. We consider here the possible application of these results to copepods, assuming that some results obtained for heavy particles are still valid for light particles. Using parameter values representative of copepod species in coastal waters and open ocean, we numerically estimate the possible enhancement of copepod contact rates due to the preferential concentration by turbulence. The assessment is done by using data from a laboratory experiment: we find from the trajectory analysis of small neutrally buoyant particles, that the preferential concentration effect increases the contact rate up to 140%. We argue that this effect may be more pronounced for higher Reynolds numbers, and may have important ecological applications.     

Scaled vehicle tire characteristics: dimensionless analysis

This article demonstrates the use of dimensional analysis for scaled vehicle tires. The motivation for this approach is the understanding of realistic nonlinear tire behavior in scaled vehicle control studies. By examining the behavior of vehicle tires within a dimensionless framework, several key tire parameters are developed that allow for an appropriate relationship between full-sized tires and scaled tires. Introducing these scalings into vehicle dynamics studies allows for the development of scaled vehicles that have a high degree of dynamic similitude with full-sized vehicles, but are safer and more economical testbeds on which to develop experimental control strategies. Experimental data are used to compare the nonlinear characteristics for sets of scaled and full-sized tires. Finally, design of a scaled vehicle based on tire characteristics is demonstrated.     

Animal dynamics based approach for modeling pedestrian crowd egress under panic conditions

Collective movement is important during emergencies such as natural disasters or terrorist attacks, when rapid egress is essential for escape. The development of quantitative theories and models to explain and predict the collective dynamics of pedestrians has been hindered by the lack of complementary data under emergency conditions. Collective patterns are not restricted to humans, but have been observed in other non-human biological systems. In this study, a mathematical model for crowd panic is derived from collective animal dynamics. The development and validation of the model is supported by data from experiments with panicking Argentine ants (Linepithema humile). A first attempt is also made to scale the model parameters for collective pedestrian traffic from those for ant traffic, by employing a scaling concept approach commonly used in biology.     

基于两点三次样条插值算法的大尺寸LCD图像缩放引擎设计

本文针对LCD控制器的图像缩放引擎,提出了一种基于两点的三次样条插值算法。该算法实现简单,不仅节省硬件开销,而且可以取得比nearest、bilinear插值算法更好的图像处理效果。文中详细阐述了图像缩放引擎的硬件实现结构以及插值滤波器的实现原理。并利用Q值评价法对提出的算法进行了客观评价,评价结果表明该算法可以取得接近于bicubic的图像处理效果。最后对图像缩放引擎进行了FPGA验证,验证结果表明图像缩放引擎工作正确,图像显示效果良好。     

On the regimes of underwater explosion for a submerged slender structure by pulsating bubble

Three regimes: near-, middle- and far-fields of underwater explosion are proposed in this study aiming at providing an overview on the responses of submerged slender structure by pulsating bubble. In the near-field, the material starts to yield, thus leading to structure breakdown immediately; remarkable structural global elastic deformation occurs in the middle-field as well as substantial movement; and a structure moves as a rigid body with negligible deformation for the far-field. Equivalent dimensionless parameters are obtained by two different dimensional analysis methods, among which a dominant similarity parameter is found out. Thus, a scaling law providing us with a relation between structural global response and the dominant similarity parameter is yielded, which can be used for demarcating the three regimes quantitatively. To demonstrate, three models corresponding to typical submarine parameters are performed in the case studies. Quantitative criterion of the three regimes is presented along with the regime diagrams. The structural global response features such as the deformation and maximal acceleration/speed of different regimes are provided as well.