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1.
回转机械扭振测量技术研究   总被引:14,自引:1,他引:13       下载免费PDF全文
本文设计出一种宽带扫描激光多普勒扭振测量仪,由于使用了宽带扫描技术,从而使得系统具有测量动态范围大、测量精度高、实时快速等特点.  相似文献
2.
纵-扭复合振动模式指数型复合超声变幅杆的研究   总被引:9,自引:0,他引:9       下载免费PDF全文
林书玉 《应用声学》1997,16(5):42-46
本文对指数型纵-扭复合振动模式的复合超声变幅杆进行了理论及实验研究,该变幅杆由均匀截面直棒及指数型截面杆组成。文中推出了变幅杆中纵向振动及扭转振动的共振频率方程,通过发迹指数型变截面棒的截面变化规律,实现了同一变幅杆中纵向振动与扭转振动的同频共振。  相似文献
3.
简明设计复合扭振变幅杆   总被引:3,自引:0,他引:3       下载免费PDF全文
传统设计复合扭振变幅杆的方法是利用各形状函数杆之间的角位移连续和力矩连续的边界条件,来确定方程中的待定系数,导出频率方程。本文利用各形状函数分界之间机械阻抗相等的方法来设计复合扭振变幅杆。可简化设计,物理意义明显。这种方法也适用于纵振复合变幅杆的设计。  相似文献
4.
基于激光多普勒技术扭振测量的研究   总被引:3,自引:0,他引:3  
黄震  刘彬  董全林 《光学学报》2006,26(3):89-392
提出一种基于激光多普勒技术和光学外差原理对高速回转机械进行扭振测量的新方法,分析了工作原理,推导出光路部分的数学模型,并通过实验分别验证了测量方法的可行性和准确性。高相干激光投射到转轴同一个截面上2点,反射光的多普勒频移正比于转轴转速,通过光学配置,使前后两个时刻的多普勒频移光信号在光探测器上发生光学混频,光电流拍差正比于转轴在两个时刻的速度差,控制两个时刻时间差很小,直接得到角加速度。与其他激光多普勒扭振测量方法相比,该方法直接测量转动角加速度,在保证测量精度的前提下,提高了扭转振动测量的实时性,极大地扩展了扭振测量的动态范围,对大型回转机械运行状态监测和故障诊断具有重要意义。  相似文献
5.
黏性介质中圆截面弹性细杆的平面振动   总被引:2,自引:0,他引:2       下载免费PDF全文
刘延柱 《物理学报》2005,54(11):4989-4993
讨论圆截面弹性细杆在黏性介质中的平面振动. 基于Kirchhoff理论,以杆中心线的Frenet坐标系为参考系,建立其动力学方程,杆中心线为任意平面曲线时,其扭转振动与弯曲振动解耦. 讨论两端固定条件下任意形状杆的平面扭转振动,以及无扭转的轴向受压直杆和圆环杆的平面弯曲振动,导出其自由振动频率和阻尼系数. 证明空间域内压杆的Lyapunov稳定性和欧拉稳定性条件为时域内渐近稳定性的充分必要条件,或无阻尼压杆的稳定性必要条件. 圆环杆平衡恒满足渐近稳定性条件.  相似文献
6.
扭转超声振动系统中局部共振的研究   总被引:2,自引:0,他引:2       下载免费PDF全文
刘世清  林书玉 《应用声学》2004,23(2):11-14,44
本文从扭转振动波动方程出发,推导出了具有类圆锥过渡段的复合阶梯型扭转变幅杆的频率方程解析表达式。从实验和理论上对该复合变幅杆的谐振频率随杆细端长度和直径的变化进行了测量和计算。通过对比,证明了复合振动系统中局部扭转共振现象的存在,并得到了其产生条件。  相似文献
7.
工具杆几何尺寸对超声扭转振动特性的影响   总被引:2,自引:0,他引:2       下载免费PDF全文
依据四端网络理论,利用机电类比方法,研究了具有类圆锥过度段的复合阶梯型变幅杆的扭转共振频率和与之相连接的工具杆的几何尺寸之间的变化关系,理论和实验符合的较好,为超声扭转加工振动系统的设计提供了参考依据。  相似文献
8.
The influence of torsional vibrations of fluorophore molecule on polarization spectra and absorption/emission vibronic band profiles of isotropic dye solutions has been considered. Basing on the concept of luminescence center (LC) and assuming that (1) electronic transitions in the LC may be assisted by torsion-vibrational excitations, and (2) reorientations of the LC can be described in terms of Stokes–Einstein rotational diffusion, the formula for time-dependent emission anisotropy, as a function of excitation, , and observation, frequencies has been obtained. It comprises depolarization by combined reorientations of the fluorophore molecule, i.e., its torsional vibrations with respect to the LC, and rotational diffusion of the LC. This approach is a generalization of the appropriate results obtained earlier by Ehrenberg and Rigler and, independently, by Chuang and Isenthal. The considered model has specific property that the torsional vibrations appear both as depolarizing factor for and as shaping factor for absorption/emission bands, resulting in the variation of the emission anisotropy across appropriate band profiles. This is demonstrated graphically using numerical results obtained for a simplified, one-dimensional torsional oscillator. It is also shown that observed absorption and emission spectra of coumarin solutions can be reproduced using this model with appropriate potentials for restoring forces.  相似文献
9.
1.IntroductionThemaximumoutputofatransformeramplitudeislimitedbythefatigueofthema-tCrialusedlll.Ifthesurfaceshearstressofatorsionaltransformer,T,isuniformalongtheaxis,inotherwords,themaximumpointofsurfaccshearstrcssisincxistent,ti.ea1lowab1coutputpowcrofthetorsionaltransformerwillenormouslyincrease.Insomecasesinwhichveryhigh-intcnsitytorsiona1ultrasonicpowerisrequired,theywil1benecessaries.Forthispurpose,wederivedthenewtypeoftorsionalangletransformer-quartcr-wavelcngthhypcrbolicsccanttaper.T…  相似文献
10.
The vibration-torsion-rotation Hamiltonian in CH3SiH3 has been investigated using Fourier transform microwave methods and tunable sideband far-infrared spectroscopy. Four different studies have been carried out. First, the Q-branch of the torsion-vibration difference band (ν12=0,ν6=3)↔(ν12=1,ν6=0) has been measured between 17.8 and 26.6 GHz. When three quanta of the torsional mode ν6 are excited in the ground vibrational state (gs) for (σ=−1) torsional sublevels with K=6, these transitions become allowed through resonant Coriolis-like coupling to the lowest lying degenerate mode ν12 with no quanta of ν6 excited. Second, direct l-doubling transitions in the state (v12=1, v6=0) have been observed between 8.3 and 17.5 GHz for both torsional sublevels σ=0 and σ=±1. In the limit that the intervibrational interactions vanish, the σ-splitting between lines of the same J would be difficult to resolve, but frequency differences of more than 1 GHz due to these interactions have been determined. Third, the (J=1←0) spectrum just below 22 GHz has been re-measured with higher resolution for 0?v6?4 in the gs and for (v6=0) in ν12. Finally, the (J=45←44) spectrum near 1 THz has been obtained for 0?v6?2 in the gs. A global data set of 3423 frequencies has been formed by merging the present 123 measurements with the data set used recently in the simultaneous analysis of the ν12 and ν5 bands by Schroderus et al. [J. Chem Phys. 115 (2001) 1392]. By refining the (gs/ν12/ν5) Hamiltonian developed in this earlier work in which the torsional motion is grouped with the vibrational degrees of freedom, a good fit to within experimental error has been obtained by varying 45 parameters. A fit of comparable quality has also been obtained using a similar analysis in which the torsional motion is grouped with the rotational degrees of freedom. The values of the molecular constants determined in the two models are compared.  相似文献
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