球面稳定同伦群π,S中的一个新非平凡元素族

证明在Adams谱序列中,积b₀ h₁ γ_s∈Ext^{[s+3,sp2q+(s+1)pq+(s-2)q+(s-3)]}A(Zp,Zp)收敛到球面稳定同伦群π S中的一个新的非零的稳定元素族,其中 3≤s相似文献   

基于遥感图像特征的分类方法研究

基于光谱特征的遥感图像信息提取方法存在分类精度和效率低的不足,在ENVI软件下采用基于灰度共生矩阵提取纹理特征的方法,将纹理特征参与到光谱特征中进行分类,并与基于光谱单源数据分类进行分析和比较。实验结果表明,纹理特征参与分类在一定程度上提高了遥感图像的分类精度。     

一元n次多项式根的园环复盖定理

本文的主要结果是利用三种不同的相容矩阵范数,分别给出了任意一个一元n次多项式的所有复根必全都落在复平面的一个园环区域内。     

Pr^3＋离子4f^15d^1组态的谱项推引

运用不同的方法详细推导了Pr^3＋4f^15d^1电子组态的光谱项,两种方法得到的光谱项完全相同,但是方法二更加简单、快捷。这对于研究Pr^3＋及其它镧系离子的真空紫外或紫外光谱具有重要的理论意义。     

软粘土中土钉支护基坑隆起分析

土钉支护失败,有相当一部分是因为软弱土层基坑底部发生隆起破坏。将圆弧滑动假设运用到土钉支护基坑隆起验算中,利用程序计算研究了基坑隆起的影响冈素,认为坡率陡缓和平台宽度大小对基坑抗隆安全系数有重要影响。提出在土钉支护设计计算中应定量考虑基坑隆起稳定性。     

急倾斜薄及中厚煤层斜坡后退放仓采煤法研究

介绍了一种适用于急倾斜薄及中厚煤层的采煤方法,旨在引起同行对急倾斜薄及中厚煤层开采技术的研究.     

空间相关的多点多维地震动合成方法

基于谱方法的随机场理论,借助功率谱密度函数来描述地震动随机场,同时考虑不同点、不同向地震动分量间的相关性,分别采用Clough-Penzien模型和屈铁军-王君杰相干模型来描述平稳自功率谱和平稳互功率谱,建立了空间相关的多点多维地震动合成方法。采用Matlab R2010b编制生成程序,并以某445m大跨度拱桥场地条件为例,生成空间相关的多点多维地震动时域样本,并将该时域样本的功率谱密度函数与目标功率谱密度函数进行对比。结果表明:模拟结果与目标值吻合较好,按照上述方法生成的多点多维地震时域样本满足要求。     

岩质高边坡的加固与整治措施

在水利水电工程主要水工建筑物施工过程中经常碰到岩质高边坡的治理问题,对这问题的分析和处理的好坏,势必影响这些主要水工建筑物的安全运行和其技术与经济运行的能力的发挥。     

Three-dimensional CoM energetics,pelvis and lower limbs joint kinematics of uphill treadmill running at high speed

ABSTRACT

The purpose of this study was to investigate the effects of slope on three-dimensional running kinematics at high speed. Thirteen male sprinters ran at high speed (7.5 m/s) on a motorised treadmill in each a level and a 5.0% slope condition. Three-dimensional motion analysis was conducted to compare centre of mass (CoM) energetics, pelvis segment and lower limb joints kinematics. We found that contact time was not affected by the slope, whereas flight time and step length were significantly shorter in uphill compared to level running. Uphill running reduced negative CoM work and increased positive CoM work compared to level running. Ankle, knee and hip joints were more flexed at initial ground contact, but only the knee was more extended at the end of stance in uphill compared to level running. Additionally, the hip joint was more abducted, and the free leg side of the pelvis was more elevated at the end of stance in uphill running. Our results demonstrate that joint motion must be developed from a more flexed/adducted position at initial contact through a greater range of motion compared to level running in order to meet the greater positive CoM work requirements in uphill running at high speed.     

Oldroyd-B流体混合过程中拟序结构的研究

采用Ｏｌｄｒｏｙｄ－Ｂ模型对高雷诺数下二维粘弹性混全过程中拟序结构的演变进行了数值研究,计算结果表明：在流场中加入聚合物,基波和次波的发展都抑制,涡量扩散加强,削弱了大涡卷垆配对的强度,减慢了配对时两的旋转运动,当Ｗｅｉｓｓｅｎｂｅｒｇ数大于１０时,在聚合物应力集中区涡量梯度加强,并出现反向涡量,因而强烈影响了拟序结构的演变。