基坑开挖对侧边土体变形性质的影响

针对当前基坑开挖土体变形的问题,利用工程中较常用的邓肯-张模型,推导出基坑分层开挖引起应力路径变化与切线模量的关系式,进而得出卸载状态下土体变形模量与切线模量的关系.再利用数值软件和室内试验,模拟研究基坑开挖过程.结果表明:基坑开挖对土体的应力路径有明显影响,应力路径的不断变化使得土体的应力状态也随之改变;排水条件不同,相同部位土体的应力-应变关系不同;应力路径和排水条件是土体变形的主要影响因素.     

R~2上的奇次相切环及其应用

本文给出了对奇次相切环具有横截同缩轨的判定方法,并应用于一个著名。维迭代映射得到了其有横截同缩轨的参数区域．     

基于扩展主题词表的页岩气领域本体构建研究

我国地质资源丰富,但资源标准化程度低、语义不一致、应用难度大。因此,按知识结构组织地质资源是地质信息管理和服务的重中之重。随着互联网技术的不断发展,基于本体的语义检索技术逐渐成为知识服务的基础与热点。与以往基于主题词表的领域本体构建方法不同,对主题词表进行了全面的扩展,概念上参照《页岩气知识读本》、《非常规油气地质》等书进行归并增删;关系上除保留《石油主题词表》的"用代分属参"基本关系外新增了方法、定义等描述信息;同时设计添加了主题词表所不具备的实例。通过一系列的概念扩展、关系扩充、属性定义和实例添加,最终清晰地展示了页岩气领域的知识脉络,为领域知识服务奠定了坚实基础。     

基于结构特征的地震剖面二维可视化方法

针对山地高陡复杂地质构造层位倾角较大,传统的可视化渲染方法破坏了地层的连续性,影响可视化效果。提出一种基于结构特征的地震剖面二维可视化方法。首先,采用邻域加权平均滤波法对地震勘探数据做预处理,提出正切值过滤法进行特征优化选择;其次,采用一种改进的相关算法来提取最具有明显结构特征的序列;最后,以结构特征序列为约束条件,进行二维渲染,输出地震剖面的二维可视化图像。实验结果表明,该方法结构特征明显,具有更好的连续性,提高了可视化的效果。     

Analysis on Nipper Balance Shaft Movement with Transmission Drive of Comber

The alternating movement of comber nipper balance shaft causes comber vibration, which is considered as the primary limitation for its velocity. First, optimal angular acceleration coefficients of nipper balance shaft were set in this study to acquire theoretical limiting angular velocity. Second,the transmission input model of the input shaft was developed by adopting a numerical approximation method and by considering the Bézier curve as the motion curve of the input shaft. Hence, the motion of nipper balance shaft was controlled. The optimum transmission driver curve of the input shaft was obtained by contrasting the analyses of the actual angular acceleration of nipper balance shaft for each optimal coefficient. Experimental tests validated the results. The nipper balance shaft of the comber reduced comber vibration because the shaft adopted the controllable unit of transmission input.Our research sheds light on the application of controlled mechanisms in textile machines and provides a theoretical basis for increasing the velocity and decreasing the vibration or noise of the comber.     

Hermite-Fejér插值在一重积分Wiener空间下的平均误差

在L2-范数下讨论基于第二类Chebyshev多项式零点的Hermite—Fejér插值多项式列在一重积分Wiener空间下的平均误差,得到了相应量的弱渐近阶．     

一类二阶拟线性瞬态方程组的Phragmén-Lindelof型二择性结果

考虑一类定义在三维半无穷柱体上的拟线性方程组, 其中假设方程的解在柱体的有限端满足非齐次条件, 在柱体的侧面上满足零边界条件. 通过对非线性项进行限制, 利用微分不等式技术, 给出该方程的解在3种不同柱体上的二择一定理, 并在衰减的情形下给出全能量的上界.     

一类热弹性板的Phragmén-Lindelof二择一结果

考虑一类含有双调和算子的热弹性板的空间性质, 通过构造一个能量函数, 利用微分不等式技术, 推导出该能量函数可由其自身一阶导数控制的微分不等式, 并给出解的Phragmén-Lindelof二择一结果.     

关于Szász-Bézier算子的点态逼近

利用统一的Ditzian-Totik光滑模,得到了Szász-Bézier算子的点态逼近正、逆以及等价定理.     

Influence of particle size and temperature on the dielectric properties of CoFe2O4 nanoparticles

The objective of this study was to establish the dielectric properties of CoFe2O4 nanoparticles with particle sizes that varied from 28.6 to 5.8 nm. CoFe2O4 nanoparticles were synthesized using a chemical coprecipitation method. The particle sizes were calculated accord-ing to the Scherrer formula using X-ray diffraction （XRD） peaks, and the particle size distribution curves were constructed by using field-emission scanning electron microscopy （FESEM） images. The dielectric permittivity and loss tangents of the samples were determined in the frequency range of 1 kHz to 1 MHz and in the temperature range of 300 to 10 K. Both the dielectric permittivity and the loss tangent were found to decrease with increasing frequency and decreasing temperature. For the smallest CoFe2O4 nanoparticle size, the dielectric per-mittivity and loss tangent exhibited their highest and lowest values, respectively. This behavior is very useful for materials used in devices that operate in the microwave or radio frequency ranges.