奇摄动问题解的多层现象

讨论了一类二阶微分方程奇摄动两点边值问题 .首先求出问题的外部解 ,然后再利用伸长变量 ,构造了对应问题的内部解 ,最后利用匹配原则得到了原问题解的渐近式 ,并且指出了该解的展开式具有多层边界现象 .

含变系数的二阶奇摄动问题的多层现象

研究一类含有变系数的二阶奇摄动问题的多层现象.首先区分变系数的不同符号,把奇摄动问题划分为左(右)问题,由渐近展开法,分别构造了左(右)问题的外部解;通过引入伸长变量,各求得两个特异极限,进而获得左(右)问题的右(左)层函数和各自的中间层函数.再通过Van Dyke匹配原则对内外解进行匹配和"缝接",得到奇摄动问题的一致有效的渐近展开式,并通过一个数值算例来验证其有效性.

一类奇摄动问题解的多层现象

本文讨论了一类二阶微分方程奇振动问题,利用伸长变量,构造了对应问题的解,指出了它具有多层边界层现象。

房室交接区多层传导阻滞(附4例分析)

房室结上部（房结区）2∶1传导,结区文氏型传导为A型交替性文氏传导,最终以3个连续未下传的心房激动而终止该文氏周期。下部（结-希区或希氏束远端）2∶1阻滞为B交替性文氏周期,最终以1个或连续2个未下传的心房激动而终止该文氏周期。房室交接区3个或4个水平层面的传导阻,

Human Comfort Evaluation of a Steel-Concrete Composite Building Subjected to Aerobics

The current steel-concrete composite floors design might be susceptible to the resonance phenomenon, causing undesirable vibrations in the frequency range that is the most noticeable to humans, i.e., 4 Hz to 8 Hz. This way, the main objective of this work is to investigate the dynamic structural behaviour of a steel-concrete composite multi-storey building when subjected to human rhythmic activities （aerobics）. The studied structural model represents a typical interior floor bay of a commercial building used for gym and is composed by three floor levels spanning 20 m by 20 m, with a total area of 3×400 m2. An extensive parametric study was developed aiming to obtain the peak accelerations, RMS （root mean square） accelerations and VDV （vibration dose value） values, based on two different mathematical formulations. The human comfort of the building was analysed and the vibration transmissibility related to the steel columns was verified. Based on the found results, the investigated structural model presented high vibration levels that compromise the human comfort.