Influence of magnetic field on wear in high frequency reciprocating sliding contacts

Results of experimental studies concerning the influence of permanent magnetic field on wear of dry sliding contact operating at short stroke and high frequency are presented. It was found that horizontal magnetic field with different orientations relative to the sliding direction is affecting performance of the contact. The increase in frequency of sliding reduces accumulated mass loss and lowers the surface roughness of the wear track in the presence of magnetic field. Enhanced chemisorptions of oxygen by a ferromagnetic material due to the influence of external magnetic field is postulated.     

Atomic force microscopy study on eucaryotic ribosomes

It is tried to compare the effects of sample preparation on shapes and sizes of ribosomes deposited on mica.The apparent sizes of ribosomes in the atomic force microscopy (AFM) images are about 60nm in most cases,The height appears to be indifferent to the sample preparation method and image conditions.It is found that the dehydration may greatly affect the topography of ribosomes.The volumes of ribosomes are estimated after considering the convolution effects of AFM tip on the appearance of ribosomes.     

含高副平面运动链图及其拓扑图的自动生成

在对含高副平面运动链进行分析的基础上，本文提出了最大基环的概念，从而避免了杆与杆之间的交叉，并由计算机自动生成了八杆以内、１—３个自由度，含１—２个高副的平面运动链图及其拓扑图。     

照射型莫尔轮廓法光强测试

在单光源、双光源、不同照射角及不同距离等条件下,测试了照射型莫尔轮廓法的光强分布。分析了影响光强分布的因素。     

Limitations on maximum tree density using hyperspatial remote sensing and environmental gradient analysis

We present a novel approach for performing environmental gradient analysis to address the question: is maximum potential tree density in eastern Lake Tahoe Basin, NV limited by water, temperature/energetic constraints, or both? To address this question we fuse continuous tree density estimates derived from hyperspatial remote sensing imagery (pixels smaller than trees) with two topographically derived environmental gradients: elevation and yearly potential relative radiation (PRR). We based our analysis on the maximum tree density found in each of over 200 environmental gradient combinations found with our area of interest, drawing from a dataset consisting of over 300,000 30 m plots and over 3 million individual trees. At a given elevation, sites in which maximum tree density increases as a function of increasing yearly PRR were considered to be temperature or energy limited. Conversely, sites in which maximum tree density decreased as a function of increasing yearly PRR were considered water limited. We found that eastern Lake Tahoe appears to be a landscape which is both water limited (at lower elevation and brighter, south-facing slopes) and temperature/energy limited (at higher elevations and darker, north-facing slopes). We discuss how fusing accurate and ecologically relevant remote sensing outputs with direct and indirect continuous microclimate surfaces can provide a powerful tool for addressing major questions of tree distributions and life history parameters.     

北京市不同地貌类型开发建设项目新增水土流失预测方法研究

通过对分别位于北京山区和平原区两种地貌类型的2个开发建设项目新增水土流失预测的研究,提出了原地貌和扰动地表水土流失的预测方法。研究表明,新增水土流失的预测,主要是对原地貌和扰动地表土壤侵蚀模数的确定,确定时主要采用实测数据、类比法、水文资料查阅法以及模数修正法等。     

Finite Volume Model for Shallow Water Equations with Improved Treatment of Source Terms

A simple yet precise relation between the flux gradient and the bed slope source term is presented, which produces a net force within the cell with an inclined water surface, but ensures still water condition when there is no flow across the boundaries. The proposed method consists of calculating the pressure term based on the water depths at the cell vertices, which may be computed by a higher order scheme and the bed slope source term by a centered discretization technique. The methodology is demonstrated with a Godunov-type upwind finite volume formulation. The inviscid fluxes are calculated using Roe’s approximate Riemann solver and a second-order spatial accuracy is obtained by implementing multidimensional gradient reconstruction and slope limiting techniques. The accuracy and applicability of the numerical model is verified with a couple of test problems and a real flow example of tidal water movement in a stretch of River Hooghly in India.     

PREFERENTIAL SPUTTERING OF Cu76Ni15Sn9

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