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In this paper, a standard susceptible-infected-recovered-susceptible(SIRS) epidemic model based on the Watts–Strogatz(WS) small-world network model and the Barabsi–Albert(BA) scale-free network model is established, and a new immunization scheme — "the most common friend first immunization" is proposed, in which the most common friend's node is described as being the first immune on the second layer protection of complex networks. The propagation situations of three different immunization schemes — random immunization, high-risk immunization, and the most common friend first immunization are studied. At the same time, the dynamic behaviors are also studied on the WS small-world and the BA scale-free network. Moreover, the analytic and simulated results indicate that the immune effect of the most common friend first immunization is better than random immunization, but slightly worse than high-risk immunization. However,high-risk immunization still has some limitations. For example, it is difficult to accurately define who a direct neighbor in the life is. Compared with the traditional immunization strategies having some shortcomings, the most common friend first immunization is effective, and it is nicely consistent with the actual situation. 相似文献
93.
By utilizing a natural mercury lamp, the transverse Zeeman background correction method, which is used for trace mercury measurement in air, is studied. In this paper, a natural mercury lamp is used as a light source, and is placed in a 1.78-T magnetic field. The lamp emits two linearly polarized light beams σ± and π of 253.65-nm resonance line, which are used as bias light and absorbing light, respectively. A polarization modulation system is used to allow σ± and π light beams to pass through alternately with a certain frequency. A multipath optical cell with 12-m optical path is used to increase optical distance. Based on the system described above, the influence caused by UV absorbing gases, such as NO2, SO2, acetone, benzene, and O3, is analyzed. The results show that it may reduce the detection limit when the concentrations of these gases exceed 83.4 ppm, 20.3 ppm, 142.3 ppm, 0.85 ppm, and 0.55 ppm, respectively. The detection limit of the system is calculated and can achieve up to 1.44 ng/m3 in 10 minutes. Measurements on mercury sample gas and air are carded out, and the measured data are compared with the data of RA-915 mercury analyzer (Russia). The result shows that the correlation coefficient reaches up to 0.967. The experimental results indicate that the transverse Zeeman background correction method can be used to quantify trace mercury in air with high-precision. 相似文献
94.
通过改变激光场Rabi频率和原子-多聚物分子耦合强度, 探索了外场形式对超冷原子-多聚物分子转化效率的影响. 首先通过定义时间指数, 对文献所给出的外场做出改进, 讨论了时间指数对转化效率的影响; 然后选取一种更优化的外场形式, 其具有很好的参数鲁棒性, 该外场作用下的绝热过程几乎不存在振荡, 其绝热保真度接近于1, 系统误差较小, 可以稳定、高效地实现超冷原子-多聚物分子的转化.
关键词:
超冷多聚物分子
转化效率
外场形式
绝热保真度 相似文献
95.
Fuzhong Nian 《中国物理 B》2021,30(12):128901-128901
In a certain period, some news will compete for the top news to gain the most attention and influence, and more news will be submerged in the ocean of news and become mediocre. This article deeply studies the evolution process and competition mechanism of the dissemination of Weibo news. In this paper, we innovatively propose a pre-processing scheme for traditional small-world networks and scale-free networks and divide nodes into three roles:fans, passersby, and anti-fans. The competition mechanism of Weibo top news is defined from the aspects of node role and node aggregation degree. A network evolution model is established based on the competition mechanism. The propagation characteristics of the network evolution model are deeply analyzed, and simulation experiments are performed on the small-world network and the scale-free network. Finally, the validity and rationality of the new model are verified through comparative experiments, and a feasible scheme for the propagation of top news on Weibo is given. 相似文献
96.
研究了玻色-爱因斯坦凝聚体中非线性相互作用对量子共振棘流的影响.满足量子共振条件的周期驱动使得波包在动量空间出现弹道扩散,当波包扩散具有特定方向时,系统就出现定向的动量流.弱非线性相互作用下的冷原子分成两簇,它们分别受到方向相反的稳定周期驱动力,以各自恒定的加速度沿相反方向运动.波包在动量空间的扩散表现为两个稳定的沿相反方向运动的峰.非线性相互作用的增强使得正方向运动的冷原子减少,负方向运动的冷原子增加,从而系统的动量流减弱甚至反转.当非线性相互作用足够强时,动量空间中的波包只有一个稳定的峰,且峰值对应的动量不随时间变化.此时冷原子受的周期驱动力为零,定向的动量流消失. 相似文献
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99.
我是西吉县城关一小珠心算教师。在教珠心算乘除一口清时,没按29句“个律”、“进律”口诀来讲,而是采用乘法“九九”口诀,将本位积与进位积相迭加,来直接计算一位数乘多位数单积一口清的。我把它称作“九九造积”一口清。多年来我利用这种方法教小学生 相似文献
100.