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激光双法布里:珀罗干涉纳米测量系统的理论分布 总被引:2,自引:0,他引:2
本文设计了一种基于双法布里-珀罗干涉仪、采用计算机实时处理、以轻拍式探针为传感器的新型纳米测量系统,描述了该系统的工作原理,详细进行了系统的理论分析。提出了通过测量双法布里-珀罗干涉仪透射光强基波幅差值差或等幅值过零时间间隔的方法进行纳米测量的理论基础,分析了轻拍式探针的振动模型,给出了检测探针振幅变化的新方法及理论依据。 相似文献
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溶胶—凝胶法有机—无机精细复合材料P(VDF/TeFE)—SiO2的制备与显微 … 总被引:6,自引:0,他引:6
用溶胶-凝胶法制备了有机-无机精细复合材料P(VDF/TeFE)-SiO2。利用水解-聚合反应由正硅酸乙酯(TEOS)合成SiO2溶胶,乙醇作溶剂,盐酸作催化剂。将P(VDF/TeFE)溶于丙酮,并与SiO2溶胶均匀混合。凝胶后经干燥和热处理得到有机-无机精细复合材料P(VDF/TeFE)-SiO2。用红外光谱分析、扫描电镜分析、差示扫描热分析和热失重分析对有机-无机精细复事材料P(VDF/TeF 相似文献
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提出了一种新型基础隔震模型,即带限位装置的磨擦隔震系统(S-LF);基于此隔震模型,利用FGN法,并结合Floquet理论研究了地面谐运动下S-LF的主谐、次谐运动特性;通过与纯摩擦滑移隔震系统(P-F)和恢复力摩擦隔震系统(R-FBI)的比较表明,S-LF的隔震性能优于P-F和R-FBI。 相似文献
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:本文着重介绍了用共焦法布里-珀罗干涉仪探测固体表面超声位移的原理、干涉仪工作点的控制和探测超声位移的实验结果。 相似文献
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分析了现有光纤压力传感器的原理与结构,选择非本征型法布里-珀罗腔作为研究目标,建立了测压的数学模型,开展了微机电加工工艺研究,探索了包括研磨、腐蚀、减薄与键合等特殊工艺,批量制作的法布里-珀罗腔具有一致性;建立了一套基于机器视觉的测量与焊接系统,能够在线精确测量与焊接控制,实现光纤与准直管的焊接以及准直管与法布里-珀罗腔的焊接。利用本系统,制作出传感器灵敏度为1.765 nm/kPa,在不采用非线性拟合校正的条件下,膜片挠度-压力的线性度为99%,重复性为1%,迟滞为0.7%,温度敏感系数为0.15 nm/℃,零位长时漂移小于2 nm。 相似文献
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鼠巨噬细胞集落刺激因子-1受体(mCSF-1R)部分序列与质粒pGEX-2T谷胱苷肽转移酶(GST)融合,融合蛋白GST-CD-Pst(胞浆区),GST-CTerm(C-末端)和GST-KI(激酶插入区)成功地在大肠杆菌JM109株表达。初步结果指出:(1)GST-融合蛋白在体外激酶分析中可以作为底物;(2)由PKA导致的磷酸化可能具有生理学意义;(3)mCSF-1R被CKII磷酸化。32P标记GST-CD-Pst的磷酸氨基酸分析证实,mCSF-1R的胞浆区丝氨酸上被磷酸化,已制备抗GST-CTerm,GST-KI和GST-CD-Pst兔抗体。抗血清的筛选通过野生型32D-CSF-1R转染子免疫沉淀进行。 相似文献
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为了得到用于1.3μm光通讯窗口掺镨化镓铟(PGICE)高数值孔光纤,本文报道以ZrF4-BaF2-LaF3-AlF3-Na(Li)F-PbF2(ZBLAN(Li)Pb)和NaPO3-BaF2-ZnF2-PbF2(FPG)玻璃作为包层材料,研究了芯和包层玻璃在物理性质和化学组分上的匹配性,差热扫描(DSC)和电镜(SEM)分析表明PGICZ/ZBLAN(Li)Pb虽在物理性质上匹配,但在化学组分不 相似文献
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Suppressing vortex-induced vibration (VIV) has recently attracted numerous researchers due to its practical significance in many engineering applications. Most of the previous studies have focused on a passive or active flow control. A structurally active control approach to mitigate a two-dimensional, nonlinear coupled, cross-flow/in-line VIV has not been well studied. This paper presents a reduced-order fluid-structure dynamic model and combined analytical–numerical solutions for the efficient suppression of two-dimensional VIV of a flexibly mounted circular cylinder in uniform flows. The theoretical model is based on the use of coupled Duffing–Rayleigh oscillators with three variables describing the cylinder cross-flow/in-line displacements and the strength of the fluid vortex circulation in the cylinder wake. These equations of fluid-structure motions contain geometric and hydrodynamic nonlinearities. Closed-loop linear and nonlinear velocity feedback controllers are implemented in the transverse direction governing the larger cross-flow response than the associated in-line counterpart. Approximated analytical expressions are derived by using the harmonic balance to explicitly capture the system nonlinear dynamic features and the effects of key dimensionless parameters. Parametric investigations are carried out to evaluate the linear versus nonlinear controller performance in terms of the maximum response suppression capability and the power requirement in a wide range of reduced flow velocities, mass ratios, and control gains. Over the main lock-in resonance region with coupled cross-flow/in-line responses, the linear controller is found to be more efficient in suppressing the two-dimensional VIV by also modifying the system frequencies and phase relationships. Nevertheless, based on the power comparison, the nonlinear control is superior to the linear control for very small targeted controlled amplitudes of a very low-mass cylinder. These active control strategies may be further applied to the multimode VIV suppression of a long flexible cylinder with multi degrees of freedom. 相似文献
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混沌工程学 总被引:8,自引:0,他引:8
世界是非线性的,线性只是其近似描述,混沌的发现表明:某些确定性非线性系统具有内在的随机行为。事实上,以往20年,无所不在的混沌现象几乎在每个学科都有所报道,如数学、物理学、化学,甚至社会科学。但理论研究学者的主要兴趣在于探究混沌的本质。与此同时,混沌的实际利用在许多工程领域受到重视,如信息工程、系统工程、医药工程、农业工程、电气工程、生物工程、机械工程、土木工程等。混沌工程学是一门新的研究混沌实际利用及其基本理论的非线性工程科学。。文章对现代混沌工程学的定义、对象、概念、方法、理论与应用加以总结,并介绍其近来的进展及作者的工作。混沌工程学在国民经济与国防建设中研究的热点是:混沌分析技术,混沌控制技术与混沌生成技术。 相似文献
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Atomic coherence and interference in an atomic medium exhibiting electromagnetically induced transparency may lead to enhancement or suppression of nonlinear susceptibilities. Absorptive photon switching has been observed by constructive quantum interference, which is based on the enhanced third-order, nonlinear absorption in a four-level system. In a different four-level system, suppression of the two-photon absorption by destructive quantum interference has been observed. Experiments were carried out on 87Rb atoms cooled and confined in a magneto-optical trap and the experimental results agree with theoretical calculations of simple four-level model systems. 相似文献
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This paper presents the modeling of one kind of nonlinear parabolic distributed parameter control system. By transforming
the system to that in the fixed domain, or into the lumped parameter system, this paper provides an insight into the basic
features of the control system, as well as the critical conditions for the control variable. The equations for one-dimensional
systems of planar, cylindrical and spherical cases are formulated as a unified form, and the dynamic characteristics of the
open-loop control system and close-cycle feedback control system have been investigated. Numerical results agree well with
theoretical results. The simulation results indicate that the system is well posed, stable, measurable and controllable.
Received 16 May 2000 相似文献
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该文研究了受色噪声激励的Rayleigh-Duffing振子瞬态响应及其最优有界控制问题。在弱扰动假设下应用标准随机平均法得到了原系统振幅过程的部分平均It#x000f4;随机微分方程。应用Bellman动态规划原理,结合控制力有界条件,得到了最优有界控制率。完成所有平均过程得到了系统振幅过程的完全平均It#x000f4;随机微分方程和相应的Fokker-Planck-Kolmogorov方程。基于退化线性系统得到一组正交基空间,在此基空间内进行Galerkin变分近似求解Fokker-Planck-Kolmogorov方程得到了受控系统的瞬态响应。采用Monte-Carlo模拟验证了所有理论结果的有效性。计算表明:1)所提方法求解受最优有界控制率作用的随机非线性系统瞬态响应有效;2)最优有界控制率成功降低了系统瞬态响应;3)该方法的求解效率高于Monte-Carlo数值模拟方法。 相似文献
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