A differential equation for calculating squeeze-film air damping in slotted plates is developed by modifying the Reynolds equation. A term is added to account for the effect of airflow through the slots on the air dam...
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A differential equation for calculating squeeze-film air damping in slotted plates is developed by modifying the Reynolds equation. A term is added to account for the effect of airflow through the slots on the air damping of the plate. The end effect of the airflow in the slots is also treated by substituting an effective channel length for the geometric channel length （i. e. the thickness of the plate）..The damping pressure distribution, damping force, and damping force coefficient of the slotted plates can be found by solving the equation under appropriate boundary conditions. With restrictions on the thickness and the lateral dimensions of the slotted plate removed,the equation provides a useful tool for analysing the squeeze-film air damping effect of slotted plates with finite thickness and finite lateral dimensions. For a typical slotted plate structure, the damping force coefficient obtained by this equation agrees well with that generated by ANSYS.
复杂应用场景决定短距离无线通信系统面对多种干扰、较低硬件资源配置导致其抗干扰能力有限,为实现可靠传输,设计基于改进LDPC码的短距离跳频无线通信系统。其中,提出低复杂度校验和更新(LCU,low-complexity check sum updating)算法,...
详细信息
复杂应用场景决定短距离无线通信系统面对多种干扰、较低硬件资源配置导致其抗干扰能力有限,为实现可靠传输,设计基于改进LDPC码的短距离跳频无线通信系统。其中,提出低复杂度校验和更新(LCU,low-complexity check sum updating)算法,降低计算复杂度;提出基于MTBF(multi-threshold bit flipping)的LCU-MTBF算法,提高译码性能,降低译码复杂度。仿真结果表明,LCU算法适用于多种硬判决译码算法,在不影响原有算法性能的基础上降低译码算法的计算复杂度;LCU-MTBF在误码率(bit error rate)为10^(-5)、迭代次数为5时,获得0.15 d B性能增益,将MTBF算法中加法次数降低约40%;当误码率为10^(-4)、信噪比为15 d B时,在部分频带干扰和全频带干扰下,基于改进LDPC码的短距离跳频无线通信系统均获得7 d B左右的性能增益,有效改善其干扰性能。
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