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We propose a simple feedback cooling method, including both the component feedback and the velocity feedback,for cooling a charged particle pair in a Paul trap. It is found that the system can be cooled to periodic orbits;and if control intensity is strong, the system can be cooled to a one-periodic orbit, which is only in a horizontalplane. The result shows that the cooled system is also robust for noise. 相似文献
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The mechanism of generation and annihilation of attractors during transition from a Hamiltonian system to a dissipative system is studied numerically using the dissipative standard map. The transient process related to the formation of attracting basins of periodic attractors is studied by discussing the evolution of the KAM tori of the standard map. The result shows that as damping increases, attractors are mainly generated from elliptic orbits of the Hamiltonian system and annihilated by colliding with unstable periodic orbits originating from the corresponding hyperbolic orbits of the Hamiltonian system. The transient process also exhibits the general feature of bifurcation. 相似文献
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为了实现任务态f MRI的嗅觉刺激装置的设计和功能验证.满足嗅觉f MRI实验的自动化刺激要求.首先,针对嗅觉刺激和人体嗅觉感受的特点,结合使用环境的要求,总结嗅觉f MRI的实验设计方法,归纳出用于f MRI的嗅觉刺激装置的具体需求.将刺激装置分为气路系统和控制系统、气路系统采用洁净空气通过气味溶液产生相应的气味气体,通过多支路切换达到输出不同气味的目的;控制系统采用虚拟仪器方案,其软件基于Lab VIEW平台编程,提供可输入刺激序列的人机界面,并根据要求控制电磁阀切换不同气路.然后,使用该刺激装置对单个被试进行嗅觉刺激并成像,刺激气体采用乙酸异戊酯和吡啶,实验为组块设计,使用Siemens 3.0 T MRI仪器EPI序列进行扫描,数据处理采用基于Matlab软件的SPM8和Mars Ba R工具包.选取眶额叶和岛叶中的脑激活团簇作为感兴趣区域(ROI)进行分析,激活信号在时间上的强度变化与刺激序列变化基本一致,吡啶组块的激活信号强度大于乙酸异戊酯组块激活强度,且其强度变化比乙酸异戊酯组块更符合刺激序列.ROI分析证明刺激装置基本满足嗅觉f MRI实验需要,具有较强的可用性.此外,在相同的刺激时间和间隔时间下,人脑同一区域对不同刺激气味的激活反应可能不同. 相似文献
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1-吡唑酰基-2-烷氧基羰基肼类化合物的合成及其生物活性 总被引:2,自引:0,他引:2
4-取代-1-甲基-3-乙基-5-吡唑甲酰肼与氯甲酸酯缩合得到16个1-吡唑酰基-2-烷氧基羰基肼类化合物(2a~2h和3a~3h,其中14个是新化合物),其结构经1H NMR,IR,MS和元素分析表征。初步生物活性测试结果表明,当浓度为500μg.mL-1时,3a,3b和3 e对油菜菌核病菌抑制活性均达到90%,3d对小麦白粉病菌的抑制活性达到90%;2h对蚕豆蚜的抑制活性达到92.75%。当浓度为1 000μg.mL-1时,2h对粘虫的抑制活性达到100%。 相似文献
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本文提出了一种数值求解反应扩散方程(组)的快速差分方法。差分近似的总截断误差为O(△x^2,△t^2,(△t/△x)^2)。相容性、稳定性分析表明此差分格式能够有效地抑制非线性项带来的刚性效应和短波不稳定性。对1维和2维的Fitzhugh-Nagumo(FHN)方程的数值模拟表明此方法具有计算速度快,稳定性好(△x,△t)的稳定区域较宽,晚皇在高维空间中推广等优点,是数值求解反应扩散方程较好的数值 相似文献
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The transient properties of laser-cooled two charged particles in a Paul trap are studied numerically. We find the existence of characteristic lifetime of an attractor, which is thought to be an important feature of the transient dynamics of the weakly dissipative system. The theoretical analysis shows that it is caused by pseudo-periodic orbit which is the residual sign of periodic orbit of the focus-saddle bifurcation. Study of dissipative coupled standard maps shows that this is a general conclusion for weakly dissipative system. 相似文献
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