弹簧振子周期的探究——用力传感器探究振子质量对实验误差的影响

精确的实验测定表明，对于弹簧质量不可忽略的振动系统的振动周期总是略大于理论公式给定的周期。本文分别通过理论推导和实验探究得出当振子质量和弹簧质量满足一定关系时，忽略弹簧质量采用理论公式可以使实验误差控制在5％以内，这种情况下实验效果最佳。

加速度地震检波装置简谐振子质量块设计与分析

利用ANSYS软件,选择单晶硅作为简谐振子质量块的材料,设置模型的材料属性,创建了简谐振子质量块的实体模型,并采用智能分网的方式对模型划分网格。对质量块模型沿设置的Z轴施加惯性载荷,通过静力分析得到质量块模型的总位移为0.218×10-7m;然后对简谐振子模型进行模态分析,得到模型模态前6阶的固有频率以及各阶对应的振型图和位移云图,并分析了各阶的振动情况;最后对简谐振子质量块模型施加地震波激励信号进行谱分析,模拟地震情况下的随机振动,得到8号关键点在不同地震波频率下的位移-频率响应曲线。通过ANSYS软件的仿真分析,为简谐振子的设计和制作提供理论依据。

谐驱动力作用下的变质量谐振子

按照本文两位作者最近导出的波函数的一般解析表达式求得３种变质量谐振子在谐驱动力作用下其几率密度随时间的变化情况

质量—弹簧振子系统的ANSYS有限元分析

对质量—弹簧振子系统进行的ANSYS有限元模态分析,得出了与理论计算特征频率完全一致的结果。通过这种相互一致的印证,可以确信关于弹簧有效质量的理论计算公式是准确、可靠的。

变质量谐振子的规范不变性(英文)

本文将非相对论量子力学的规范不变表述在电偶极近似下用于电磁场中的一维带电变质量谐振子,并对三种重要的变质量谐振子给出了规范不变跃迁几率的数值结果。

轴向行进弦附带质量-弹簧振子系统特征值分析

陀螺系统的特征值问题是一个重要课题.通过构造Green函数,解决了轴向行进弦附带单质量-弹簧振子耦合系统的特征值问题.根据Green函数构造定理,给出了耦合模型Green函数的显式形式,从而得到了精确的特征方程.讨论了当振子的特征频率接近于弦线的基频时,行进弦低阶模态与振子间的耦合作用,采用特征频率的最大变化定量地表征了这种耦合强度.数值结果表明:耦合系统的特征频率随着弹簧刚度的增大而增大,随着行进速度的增大而减小.最后,给出了系统可能出现重根的条件.

弹簧振子运动周期公式的研究及学生实验的开设

弹簧振子运动周期公式的研究及学生实验的开设李德洪（四川省邮电学校６１００６７）在简谐振动的理论教学中，教材以弹簧振子为例．在简要地介绍了弹簧振子的运动情况后，对弹簧振子运动的周期定量的给出了公式和简要地论述了周期与质量、倔强系数、振幅等物理量的关系．...

一节课题研究课的设计、实施与思考

在普通高中新教材物理教科书中均编入了课题研究内容.新教学大纲规定每个年级物理课程至少要安排两个研究课题,旨在培养学生综合运用知识的能力、收集处理信息的能力、分析和解决问题的能力、语言表达能力及团结协作能力,以及培养学生独立思考的习惯,激发学生的创新意识.基于以上设想,我们尝试设计了"研究弹簧振子的周期与振子质量关系"这一课题研究.

Voltage property analysis of piezoelectric floating mass actuator used in middle ear implant

Aiming at a kind of middle ear implant（MEI）, the driving voltage of a piezoelectric floating mass actuator is analyzed using a 0. 7Pb （Mg1/3Nb2/3） O3-0. 3PbTiO3 （ PMN- 30% PT）stack as a new type of vibrator. For the purpose of facilitating the analysis, a simplified coupling model of the ossicular chain and the piezoelectric actuator is constructed. First, a finite element model of a human middle ear is constructed by reverse engineering technology, and the validity of this model is confirmed by comparing the simulated motion of the stapes footplate obtained by this model with experimental measurements. Then the displacement impedance of the incus long process is analyzed, and a single mass-spring-damper equivalent model of the ossicular chain attached with the clamp is derived. Finally, a simplified coupling model of the ossicular chain and the piezoelectric actuator is established and used to analyze the driving voltage property of the actuator. The results show that the required driving voltage decreases with the increase in the frequency, and the maximum required driving voltage is 20. 9 V in the voice frequencies. However, in the mid-high frequencies where most sensorineural hearing loss occurs, the maximum required driving voltage is 3.8 V, which meets the low-voltage and low-power requirements of the MEI.

新型300Hz环路双作用热声发动机多单元串联的性能分析

对新型300 Hz质量片-膜环路双作用热声发动机的多单元结构进行了研究,详细考察了3单元、4单元、5单元、6单元结构下系统无负载和外接负载时的性能。系统无负载时,重点考察了发动机单元中核心参数的沿程分布;系统接负载时,重点考察了输出特性和最佳负载阻抗下加热功率对系统性能的影响。计算结果表明,增加环路双作用热声发动机的单元数会导致热声转换效率的降低,但能显著提高系统的输入加热功率,从而使系统获得更多的总输出声功。

声表面波梁式加速度传感器的优化设计

为获得传感器的优化设计,对一种声表面波梁式加速度传感器敏感机理进行了研究。从声波波动方程出发,结合有限元分析以及微扰理论对加速度作用力作用下声表面波传播特性进行分析,以此构建梁式声表面波加速度传感器敏感机理的理论模型,特别分析了压电梁材料及几何结构、振子质量对传感响应的贡献以确定传感器优化的几何参数。为验证理论分析结果,实验研制了基于ST-X石英悬臂梁结构的差分振荡式声表面波加速度传感器,并利用精密振动台对所研制传感器性能进行评价。实验结果显示,在给定加速度测试范围内,采用ST-X石英梁并延长梁长度、降低梁厚度以及采用较大的阵子质量将有效的改善传感器检测灵敏度,在±2 g范围内加速度灵敏度可达27 k Hz/g,且实验结果很好的验证了理论模型。

外转子风机轴向振动及故障机理研究

针对国内第一条低速磁浮辅助变流器外转子风机短期失效问题,建立了风机轴向振动弹性基础双质量振子系统动力学模型,并推导了系统位移频响的解析解,结合线路运行振动试验、风机装车频响测试、实验室台架安装变频运行试验及频响测试,揭示了该外转子风机出现早期异音、卡阻故障表象的机理为:风机第4阶电磁激振力波及电流谐波激励与其定、转子轴向同向运动模态产生耦合共振,致使转子轴承内圈、支撑转子轴的碟形弹簧及碟形弹簧卡环间产生了剧烈相对振动,从而在风机工作过程中发生了周向滑移和摩擦。在此基础上,提出了一种故障振动形态定位及复现的方法及相应的载荷谱制定方法,并在振动台上成功复现故障。最后,系统地分析了外转子风机定、转子间的刚度和阻尼、风机支撑结构的刚度和阻尼及安装基础的弹性对系统轴向振动特性的影响,从提高外转子风机振动可靠性和减小传递给基础的激励出发,给出了系统结构优化设计的建议。研究工作对类似于外转子风机这类,弹性安装的双质量振子系统的结构设计、电机轴向振动的抑制、轴承故障的定位和复现有重要的理论价值和工程指导意义。

磁浮车辆辅助变流器的风机轴承振动失效分析

针对磁浮列车辅助变流器的外转子风机轴承短期内失效问题,首先开展风机装车线路运行和台架安装变频运行的振动测试和频响测试,结合外转子风机双质量振子系统的分析,揭示风机轴承过度磨损故障的原因为耦合共振,耦合共振是由风机4倍电磁激振力波及4倍电流谐波激励与其定转子同向运动轴向振动模态产生的。然后提出基于故障振动形态和实测载荷谱归纳方法的故障复现试验方案,并在振动台上成功复现故障。最后给出调整波形弹片的刚度、优化辅助变流器电源谐波电流和适当提高风机转速的整改方案。研究成果可为类似结构的故障定位、分析和复现提供理论指导。

Structural Description of Polyaromatic Nucleus in Residue

The proton nuclear magnetic resonance spectroscopy （1H-NMR）, the synchronous fluorescence spectrometry （SFS） and the ruthenium ions catalyzed oxidation （RICO） method were used to determine the chemical structure of polyaromatic nucleus in Oman residue fractions. The results of 1H-NMR analyses showed that the average numbers of aromatic rings in the aromatics, resins and asphaltenes units were 3.2, 5.6 and 8.2, respectively. SFS was used to investigate the distribution of aromatic rings in residue fractions, the main distribution range of aromatic rings in aromatics, resins and asphaltenes were 3 4 rings, 3--5 rings and more than 5 rings, respectively. The aromatic network in residue fractions was oxidized to produce numerous carboxylic acids. The types and content of benzenepolycarboxylic acids, such as phthalic acid, benzenetricarboxylic acids, benzenetetracarboxylic acids, benzenepentacarboxylic acid and benzenehexacarboxylic acid disclosed the condensed types of aromatic nuclei in the core. The biphenyl fraction （BIPH）, the cata-condensed fraction （CATA）, the peri-condensed fraction （PERI） and the condensed index （BCI） were calculated based on the benzenepolycarboxylic acids formed. The results implied that there was less biphenyl type structures in all residue fractions. The aromatics fraction was almost composed of the cata-condensed type system, and the asphaltenes fraction was wholly composed of the peri-condensed type system, while in the resins fraction co-existed the two types, herein the peri-con- densed type was predominant over the cata-condensed type. Based on the analytical results obtained in the study, the components --aromatics, resins and asphaltenes -- were given the likely structural models.

Modal analysis on transverse vibration of axially moving roller chain coupled with lumped mass

The modal characteristics of the transverse vibration of an axially moving roller chain coupled with lumped mass were analyzed.The chain system was modeled by using the multi-body dynamics theory and the governing equations were derived by means of Lagrange's equations.The effects of the parameters,such as the axially moving velocity of the chain,the tension force,the weight of lumped mass and its time-variable assign position in chain span,on the modal characteristics of transverse vibration for roller chain were investigated.The numerical examples were given.It is found that the natural frequencies and the corresponding mode shapes of the transverse vibration for roller chain coupled with lumped mass change significantly when the variations of above parameters are considered.With the movement of the chain strand,the natural frequencies present a fluctuating phenomenon,which is different from the uniform chain.The higher the order of mode is,the greater the fluctuating magnitude and frequency are.

Quantitative Analysis Using Fourier Transform Ion Cyclotron Resonance Mass Spectrometry and Correlation between Mass Spectrometry Data and Sulfur Content of Crude Oils

Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR MS) has become a powerful tool for analyzing the detailed composition of petroleum samples. However, the correlation between the numerous peaks obtained by FT-ICR MS and bulk properties of petroleum samples is still a challenge. In this study, the internal standard method was applied for the quantitative analysis of four straight-run vacuum gas oils(VGO) by atmospheric pressure photoionization(APPI) FT-ICR MS. The heteroatom class distribution of these VGO samples turned to be different when the concentration changed. Linear relationship between the normalized abundance and the concentration of VGO samples was identified for the total aromatic compounds, aromatic hydrocarbons, S1 and N1 species. The differences of the response factors were also discussed. The sulfur contents of a series of crude oils were proved to be linear with the FT-ICR MS data calibrated by the response factor of S1 species. This study demonstrated the feasibility of the internal standard method in quantitative analysis with APPI FT-ICR MS, and the bulk properties of petroleum samples could be correlated directly with the FT-ICR MS data.

Correction of Relativistic Center-of-Mass Vector on Electric Polarizability of Pion Meson

We estimate the correction of relativistic center-of-mass vector on electric polarizability of an equal-mass quark-antiquark system numerically. Effect on the system confined by different interactive potentials is analysed. A great improvement for the electric polarizability of pion meson is obtained.

Generalized Harmonic Oscillator and the Schrdinger Equation with Position-Dependent Mass

We study the generalized harmonic oscillator that has both the position-dependent mass and the potential depending on the form of mass function in a more general framework. The explicit expressions of the eigenvalue and eigenfunction for such a system are given, they have the same forms as those for the usual harmonic oscillator with constant mass. The coherent state and its properties corresponding effective potentials for several mass functions, for the system with PDM are also discussed. We give the the systems with such potentials are isospectral to the usual harmonic oscillator.

Interference Phase of Neutrino Oscillation in Schwarzschild-de Sitter Space-Time

We study the mass neutrino interference phase in Schwarzschild-de Sitter space time along the null trajectory and the geodesic line and obtain the effects of cosmological constant A on the neutrino oscillation. Firstly, in the high energy limit, we find that the phase along the geodesic keeps the double of that along the null. Secondly, we calculate the phase on the condition that the cosmological constant, A, is a small quantity. The correction of the phase due to A is given. Finally, we calculate the proper oscillation length in Schwarzschild-de Sitter space-time, which increases because of the existence of A, compared with the result in Schwarzschild space-time. All of our results can be reduced to those in Schwarzschild space-time as A approaches to zero.