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In this paper, a modified normal form approach for obtaining normal forms of parametrically excited systems is presented. This approach provides a number of significant advantages over the existing normal form approaches, and improves the associated calculations. The approach lends itself more readily to symbolic calculations, like MAPLE, and the calculations of normal forms, together with the associated coefficients, are carried out much more conveniently. Four examples are presented to illustrate the approach. All examples include a comparison of the results obtained by the methods of normal forms and averaging. Example 4 contains a comparison of the results obtained by the normal form approach and Liapunov-Schmidt method as well. 相似文献
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简述了参量激励型水波孤子的最新研究结果,其中包括孤子-孤子的相互作用,稳定单孤子链的极性排列规则,以及孤子链的有序时空振荡等.数值研究表明,实验现象可由带阻尼的参量驱动非线性薛定谔方程描述和解释. 相似文献
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The vibration response of a spring-mass-damper system with a parametrically excited pendulum hinged to the mass is investigated using the harmonic balance method. The approximate results are found to be fairly consistent with those obtained by the numerical calculation. The vibrating regions of the pendulum system are obtained which are similar to those given by Mathieu's equation. Based on the analysis of three parameters in the response equation, the characteristics of response of the system are clarified. The stabilities of the harmonic solutions are analyzed, and finally our proposed approximation is verified compared with the numerical results. 相似文献
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利用激光激发原子荧光光谱方法分析海洋沉积物样品中的痕量钯 总被引:2,自引:0,他引:2
本文介绍了激光激发原子荧光光谱分析方法及实验谱仪装置,利用这套谱仪共对36个我国东海大陆架沉积物样品中的钯进行了分析测量。 相似文献
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Introducing a model nanostructured chain, we study the electronic properties of one-dimensional ordered nanostructured solids in terms of an exact Green's function renormalization-group approach, It is found that two kinds of electronic state, namely localized state and extended statess exist in certain energy regions. As the grain size decreases, the energy regions corresponding to the extended quantity, as well as the gaps, become wider, while the number of the isolated peaks decreases. Furthermore, the appearances of isolated peaks are mainly, due to the modulations of the interface sites. 相似文献
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Based on the concepts of a subsystem structural dynamics approach, a general power flow analysis of an indeterminate vibrating system consisting of three rods is presented and discussed. This is achieved by complementing the normal dynamic equations with geometrical compatibility equations allowing assessment of power flow dynamic characteristics applied to and excited within the system. The method may be classified as a form of substructuring using free-free interface conditions. The displacement contribution of the external and boundary coupling forces is deduced, permitting the power flow between the interfaces of substructures to be determined. The method presented is used in a power flow analysis of a simple rod truss system and in a more complex system as demonstrated. 相似文献
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复相系平衡条件及平衡稳定性条件的分析曾丹苓(重庆大学热力工程系重庆630044)关键词复相系,平衡条件,平衡稳定性条件1引言汽液相变是工程上常见的现象,它是一个复杂的物理过程,涉及到传热传质、相转变、表面现象、流体流动及工质热物性等领域,但从热力学的... 相似文献
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影响多碱光电阴极稳定性的因素很多,诸如管子的管型结构、管子的真空状况、阴极制作工艺、管子的存放及其使用条件等。本文主要从工艺角度分析影响多碱光电阴极稳定性因素,并提出改进措施。 相似文献
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利用谱线宽度测人发中的微量元素 总被引:2,自引:0,他引:2
通过实验证明了可以利用谱线宽度做永久工作曲线用于光谱定量分析。给出了用于测量人发中微量元素Cu,Zn,Fe和Ca的永久工作曲线,利用这些工作曲线对实际样品进行了测定,所得结果与用ICP-AES测得的结果相吻合。 相似文献
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计算机差谱法消除ICP-AES中光谱干扰 总被引:2,自引:0,他引:2
本文提出了在光电二极管阵列检测器-ICP-AES与微机处理的联机系统中,采用差谱法以直接消除光谱干扰的方法。详细讨论了差谱原理,差谱程序及差谱效果。应用差谱法测定了两个参考样品,结果符合要求。 相似文献
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本文通过对电子陷获型红外上转换材料的激发光谱和发光光谱特性曲线的测试,论证该材料与一般红外器件相比,具有响应光谱范围广(0.8~1.6μm)等优点,为该材料的推广应用提供了可靠的依据。 相似文献
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HT-7U是一个先进的等离子体稳态托卡马克装置.它的环向磁场(TF)和极向磁场(PF)系统,均采用超导磁体,所有超导磁体均由CICC导体制成.为了获得PF和TF磁体运行的的安全裕度,需要对这些超导线圈进行严谨的热工水力特性分析,研究超导磁体在正常运行条件下所能承受的最大扰动.稳定裕度的分析充分考虑了多种不同的扰动.本文的分析均基于修改的Gandalf程序,即考虑超导CICC磁体系统之间(匝间、层间、不同的冷却通道之间)的热耦合,研究了HT-7U超导托卡马克系统的TF和PF超导线圈在不同运行条件下的稳定裕度和失超传播特性.这些分析将为HT-7U超导磁体系统的运行提供参考. 相似文献
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高气压氯化氙准分子激光放电的稳定性与HCl的浓度有关。本文分析了放电等离子体的电子连续性方程,指出均匀放电的持续时间与HCl浓度平方根成反比。该结果与X射线预电离脉冲形成网络泵浦氯化氙激光的实验能很好地符合。
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