一类线性项前系数可变号的高阶中立型泛函微分方程的周期解

利用重合度理论,研究一类线性项前系数可变号的高阶中立型泛函微分方程的周期解存在性问题,得到了其周期解存在唯一性的新结果.有趣的是系数β（t）可变号,推广和改进了已有文献的相关结果.     

Dragload and Downdrag Performances of Inclined Pile Group Embedded in Consolidating Soil

The performance of inclined pile group embedded in consolidating soil under surcharge load was investigated by experiment in comparison with vertical pile group and single pile under the same conditions; dragload, downdrag, and layered soil settlement were measured. A three-dimensional numerical model was built via FLAC3D software, and verified by the experimental results. Influence factors, such as consolidation time, pile spacing, and pile tilt angle were analyzed. The results show that dragload of inclined pile group increases with the increase of consolidation time and pile spacing or the decrease of pile tilt angle. Downdrag of inclined pile group increases with the increase of consolidation time, pile spacing and pile tilt angle.     

具有连续分布时滞的二阶中立型方程的振动性

考虑一类具有连续分布时滞的二阶非线性中立型方程,获得了其所有解振动的充分条件。     

两个期权定价模型的比较

我们首先给出Black-Scholes期权定价模型,并用鞅方法导出其定价公式,然后引入O-U过程期权定价模型,通过分析比较发现这两个模型都满足相同的随机微分方程,并且在此两模型下期权具有相同的价格.     

汉语语音在词类教学中的特殊作用

词类的划分属于语法范畴,语法是语言的结构规则,在汉语中主要通过语序和虚词体现,表面看起来和语音毫不相干,但是,在判断词类时,经常要考虑到语音因素,如声调的变化、轻声、儿化都影响到词类的划分,由此看来,汉语语音在词类的划分中有着特殊的作用。     

艺术形象中的女性"身体"隐喻——以"铁姑娘"与"超女"为例

图像与文化、社会、政治之间总是存在着某些关系。与其说图像是被"创造"出来的,不如说是"制造"出来的,其中的艺术形象并非艺术家们凭空想象出来的,它是有现实社会依据的,是艺术家所处时代的产物。而女性形象作为一种视觉图像也成为了一个反思社会生活的符号代码。女人社会地位的变迁从中国的20世纪到21世纪大致经历了五四时期、解放后、文革时期、改革开放以来这四个阶段。女性作为艺术母题,是艺术家表现个人意识、情感的载体,始终与那个时代人的精神倾向密切相关。无论是"铁姑娘"还是"超女",不可避免地都被贴上了"政治"的标签。在现实社会中处于主导力量的政治对艺术无疑具有支配地位,同样,作为上层建筑的艺术文化也成为政治变革不可或缺的因素。     

中立型延迟积分微分方程Runge-Kutta法的渐近稳定性

针对一类渐近稳定的中立型延迟积分微分方程(NDI DEs),讨论Runge-Kut t a法的渐近稳定性.证明了Runge-Kut t a法渐近稳定的充分必要条件是该方法是A-稳定的。     

Fast fault isolation and restoration of looped MV network

A new fault isolation and restoration technique employing local Ethemet network for the looped MV circuit is presented. It can isolate all short circuit faults in the loop within 300 ms and restore the supply of healthy sections in less than 1.2 s. A reliable fault location method of isolating the single phase-to-ground fault （SPGF） in the non-effectively earthed network, which makes use of the fault generated transient signals, is also proposed. And the method locates the SPGF by examining transient zero-mode current correlation, which is not influenced by the neutral grounding mode and need no additional device. Laboratory test and simulation results show the proposed techniques are feasible, and significantly improve the supply reliability.     

一类具分布偏差变元的二阶中立型微分方程的振动性

文章讨论了一类具分布偏差变元的二阶中立型微分方程的振动性,得到了该方程解振动的一些好的结果．     

钢筋混凝土梁柱多点轴向位移式应变仪

以钢筋混凝土简支梁正截面实验教学为例,分析了钢筋混凝土梁、柱轴向应变常用测试方法和存在问题;论述了钢筋混凝土梁柱多点轴向位移式应变仪的研制思路、测试原理;比较了各种轴向应变测试方法的优缺点。