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991.
极点识别的自适应信号综合法 总被引:1,自引:0,他引:1
本文介绍了一种基于极点的雷达目标识别方案──自适应信号综合法。该方法无需知道目标的极点,利用所合成的与目标空间取向无关的识别信号对雷达后期回波处理的结果,进行目标识别。论文阐述了自适应信号综合法的工作机理、抗噪声性能,并给出计算机模拟结果。 相似文献
992.
993.
通过在克隆选择过程中引入抗体聚类机制,提出了一种用于复杂多模函数优化的新算法.通过聚类将抗体群分成多个子种群来实现其克隆选择策略,加速克隆扩增,从而提高抗体成熟力及亲和性.采用了混合超变异算子,使其能快速获取全局及局部最优.实验仿真结果表明:该算法对复杂函数寻优的过程是相当有效的,具备良好的全局和局部收敛可靠性. 相似文献
994.
本文通过对海孜矿矿井废水组成和水质情况分析,通过物理化学方法进行水质处理,使其水质满足矿井生产需要,做到了矿井生产用水的循环利用,有效地节约了水资源,保护了环境。 相似文献
995.
介绍了一种零中频DSSS(直接序列扩频)数字接收机的基带算法方案.给出了PN码捕获及跟踪、载波解调和自动频率控制算法,最后给出系统性能仿真分析.该方案具有较强抗噪声能力,算法复杂度低,基带数字信号处理部分仅用一片APEX20KE就可完成. 相似文献
996.
Homoharringtonine induces apoptosis of endothelium and down-regulates VEGF expression of K562 cells 总被引:2,自引:0,他引:2
Homoharringtonine (HHT) has currently been used successfully in the treatment of acute and chronic myeloid leukemias and has been shown to induce apoptosis of different types of leukemic cells in vitro. Emerging evidence suggests that angiogenesis may play an important role in hematological malignancies, such as leukemia. However, whether HHT can relieve leukemia by anti-angiogenesis is still unknown. We investigated the anti-angiogenesis potential of HHT with the human umbilical vein endothelial cell line (ECV304) and leukemic cell line (K562) in vitro. Cellular proliferation was determined by MTT assay and apoptosis was analyzed by flow cytometry, The mRNA expression of vascular endothelial growth factor (VEGF) was assessed by RT-PCR and VEGF protein production was detected by Western blot. Inhibition of cell proliferation and induction of apoptosis by HHT were discovered in ECV304 cells, and appeared in a dose- and time-dependent manner, Also, treatment with HHT caused down-regulation of VEGF mRNA expression in K562 cells in similar dose- and time-dependent manner and inhibition of VEGF protein production in K562 cells in response to the enhancing concentration of HHT. The results demonstrated that HHT could also induce apoptosis in endothelium and down-regulate VEGF expression in K562 cells. In conclusion, we believe HHT has anti-angiogenesis potential and speculate that HHT might exert its anti-leukemia effects via reduction of angiogenesis. 相似文献
997.
WANG NingQian BO Lin ZHANG Fan TAN XiaoDong YANG XiaoLi XIAO ZhongJu 《科学通报(英文版)》2013,58(11):1274-1284
In this study, we investigated the features of latency-amplitude (L-A) functions at different sound frequencies, using extracellular recording from auditory neurons in the central nucleus of the inferior colliculus (ICC) in mice. Isofrequency L-A functions from single neurons could be fit with a newly developed equation based on Pieron’s law. The high degree of fitness indicates that the curvatures of all isofrequency L-A functions for a given neuron are similar, and that the difference between L-A functions is due to a shift in their positions in the coordinate system. When we normalized the L-A functions to match the position of the L-A function obtained at the neuronal characteristic frequency (CF), all isofrequency L-A functions from a given ICC neuron were highly superimposed. The similar shapes of the L-A functions at different frequencies may reflect the physical laws of sound being transferred into bioelectric signals. The position of a non-CF L-A function could be measured as the differences of the asymptotic L and A ( L and A) compared to the L-A function at a reference frequency such as the CF. The nerve fibers and synapses connecting to a neuron for acoustic information processing can be functionally simplified as a single wire (as the total length of nerve fibers) and joint (as the summated size/strength of synapses). The wire and joint mediate information transmission and transduction, respectively. Thus, L and A may be measurements of the total length of nerve fibers and the strength of summated synapses in the activated auditory pathway. L and A differed between frequency channels and neurons, suggesting that the differences of acoustic neuronal responses are always caused by activation of different pathways, and that the pathways that process sounds are diverse. 相似文献
998.
【目的】由于AdaBoost算法弱分类器对各待测样本其投票权重是固定不变的,这会导致使用该算法进行分类时准确性不高,于是针对该问题提出了一种结合静态权重与动态权重的学习算法AdaBoost_DW。【方法】该算法保留了AdaBoost算法训练阶段产生的全部弱分类器,在预测阶段加入了能度量待测样本与各个弱分类器适应性的动态权重,通过双权重共同决定该弱分类器的投票权重。【结果】实验结果表明,AdaBoost_DW算法的分类精度绝大多数情况下高于原AdaBoost算法。【结论】证明了动态权重的加入能够提高原AdaBoost算法在各数据集上的分类准确率。 相似文献
999.
根据电磁理论,推导了在固体中激光超声产生的热膨胀机理和电子机理。研究了激光超声信号的光学检测方法。结果表明,激光超声可以重复产生窄脉冲,在时间和空间具有极高的分辨率,适用于材料的无损检测。 相似文献
1000.