欠阻尼振动的合成实验研究

本文利用ＪＧＹＷ－２型双单摆振动示波装置研究和探讨了两个相互垂直方向同频率欠阻尼振动的合成和两个同方向频率相近的欠阻尼振动的合成．通过实验观察和理论分析，得到了欠阻尼振动合成的部分图形和表达式，揭示了等角螺线的物理意义．     

欠阻尼振动的合成与对数螺线

欠阻尼振动的合成与对数螺线宋燕盛，包爱东，宋华珠（吉林工学院长春１３００１２）在实际的振动系统中，总是存在着阻尼，研究阻尼振动具有普遍意义和实际意义．我们用振动示波装置”‘考察了两个相互垂直、同频率、同振幅、位相差为的欠阻尼振动的合成，其合成振动曲线...     

等角螺线的物理意义

本文通过对两个欠阻尼振动合成的实验观察与理论分析得出了当两个欠阻尼振动满足一定条件时其合成振动曲线为一等角螺线，从而揭示了数学上等角螺线的物理意义．     

基于MATLAB的振动合成及左旋与右旋的动态模拟演示

应用MATLAB的图形功能,进行了相互垂直、不同频率的振动合成演示实验,很方便地得到李萨育图形.应用MATLAB图形连续播放命令,演示了相互垂直同频率的振动合成轨迹与其相位差的对应关系,使左旋与右旋等抽象的概念得以直观显现.     

各种利萨如图形的演示实验

各种利萨如图形的演示实验行小帅（山西师大物理系）本文介绍演示出多种多样的利萨如图形．利萨如图形原指两个相互垂直振动的正弦形振动的合成图形．现在介绍相互垂直的各种类型振动的合成，说明任意两种不同的波形均可以合成奇妙的、有趣的各种利萨如图形，这种演示能够...     

任意角度振动合成演示装置

任意角度振动合成演示装置唐川（华中理工大学物理系武汉４３００７４）本演示装置是利用两个相互独立的光杠杆简谐振动源，使激光斑点参与两个独立的简谐振动，用串联的形式进行振动的合成，将合成后的激光斑点投影到屏幕或墙面上进行观察．光杠杆简谐振动源如图１所示，...     

3－（9－芴甲氧基羰基）－四氢噻唑－2－硫酮振动光谱的简正坐标分析

本文采用简化一般价力场对３－（９－药甲氧基羰基）－四氢噻唑－２－疏酮（简称Ｆｍｏｃ－ＴＴＴ）分子的振动光谱做了简正坐标分析计算，得到了一套合理的精化力常数。并对Ｆｍｏｃ－ＴＴＴ分子的振动频率进行了指认。其计算频率与实验频率的平均百分误差为０．６９１。     

H2SiCl2 中 SiH 伸缩振动的泛频光谱

在2000 ～ 9000 波数 、 12000 ～12900 波数的光谱区间记录了室温下H2SiCl2气体分子的振动泛频光谱，所用的仪器分别是高分辨傅立叶变换光谱仪和高灵敏激光腔内吸收光谱仪。用局域模模型和包含达林－丹尼生共振的简正模模型，归属了SiH伸缩振动的基频和泛频，振动量子数的改变△VSiH=1, 2, 3, 4 and 6。通过对实验能级的非线性拟合，得到SiH伸缩振动的谐振频率ωm、非谐性常数χm、键间耦合系数λ、莫尔斯振子参数 De、α 和相互作用力常数 。实验发现，随着振动能量的增加，振动簇（manifold，两个SiH键的伸缩振动量子数m+n=常数 ）中能量最低的两个能级的间距逐渐减小。当△VSiH≥4时，在实验误差范围内这两个最低的振动态能级简并。这种简并的能级结构类似双原子莫尔斯振子，符合Birge-Sponer 关系。双原子莫尔斯振子直接描述了H2SiCl2分子中SiH 的高泛频伸缩振动，表明在高振动情况下振动能量已经集中到单个SiH键上。     

利用数字示波器演示简谐振动的叠加

用时间的单一谐和函数,即一个余弦或者正弦函数描述的简谐振动,是物理学中最简单、最基本的振动。利用数字任意波信号发生器和数字示波器,分别演示了同方向同频率、相互垂直的同频率以及同方向不同频率的两个简谐振动的合成。在教学过程中通过上述直观演示,有助于学生对简谐振动中振幅、周期、频率以及相位等基本概念的认识,同时对振动的叠加也有更深入的理解。     

振动光谱法研究γ—球蛋白同银（Ⅰ）离子的作用

和Ｒａｍａｎ和ＦＴＩＲ光谱法研究了γ－球蛋白同银（Ｉ）离子的相互作用，结果表明，γ－球蛋白表面的氨基酸残基可同银（Ⅰ）离子反应，生成２或４配位的物种。其振动光谱在酰胺带区域呈现明显差异。研究了在恒定的加热温度下不同反应时间对振动Ｒａｍａｎ光谱的影响，结果表明，Ｒａｍａｎ光谱强度在１５ｍｉｎ左右有最大值，当时间超过１５ｍｉｎ后，物种中的银了子被还原为单质银。     

弹簧的振动

本文给出了考虑弹簧质量时弹簧振子的一般运动规律,推出振子的振动频率公式以及超越方程xtanx=c的解的渐近表示.     

GLOBAL CONTROL OF STRUCTURAL VIBRATION USING MULTIPLE-TUNED TUNABLE VIBRATION NEUTRALIZERS

Tunable vibration absorbers are used to control vibration due to time-varying harmonic disturbances. Either vibration which is local to the neutralizer, or global vibration of the host structure can be chosen as the quantity to be suppressed. In this paper, the latter is the subject of investigation, but using multiple neutralizers rather than a single device. It is shown that by positioning these devices carefully, the global vibration of a structure (as characterized by its kinetic energy) can be effectively reduced at each single frequency in the frequency range of interest, and is comparable to the performance of active control. A methodology on how to correctly position the devices, an on how to determine their optimum mass is suggested.     

VIBRATION CHARACTERISTICS OF SLOTTED SHAFTS

The dynamics of asymmetric rotors has been investigated in the literature. However, considering the importance in the practical fields, the vibration characteristics of slotted shafts are not studied in detail. It needs more attention particularly with the emerging of new materials, such as composites for shafts. The present study aims at the analysis of the slotted shafts including the compensatory inertia slots. Also, the slotted composite shaft has been modelled based on first order shear deformation theory using finite element method with shell elements. Different materials such as, Boron epoxy, Carbon epoxy and Graphite epoxy have been tried for various stacking sequences. The slot parameters, stacking sequences and material properties have found to influence to great extent on the vibrational characteristics of rotors. The results are compared with those of isotropic slotted shaft.     

GUIDELINES FOR WHOLE-BODY VIBRATION HEALTH SURVEILLANCE

There is strong epidemiological evidence that occupational exposure to WBV is associated with an increased risk of low back pain (LBP), sciatic pain, and degenerative changes in the spinal system, including lumbar intervertebral disc disorders. A prototype health surveillance scheme for WBV is presented in this paper. Surveillance is the collection, analysis, and dissemination of data for the purpose of prevention. The aims are to assess health status and diagnose vibration-induced disorders at an early stage, to inform the workers on the potential risk associated with vibration exposure, to give preventive advice to employers and employees and to control whether preventive measures which have been taken, were successful. It is suggested that a pre-placement health examination should be offered to each worker who will be exposed to WBV so as to make the worker aware of the hazards, to obtain baseline health data, and to identify medical conditions that may increase the risk due to WBV. The case history should focus on personal history, work history, and leisure activities involving driving of vehicles. The personal medical history should detail back pain complaints, disorders in the spine, any injuries or surgery to the musculoskeletal system. A physical examination on the lower back should be performed on workers who have experienced LBP symptoms over the past 12 months. The preplacement examination should be followed by periodic health reassessment with a regular interval according to the legislation of the country. It is suggested that periodic medical examination should be made available at least every 2 years to all workers who are exposed to WBV. Any change in vibration exposure at the workplace should be reported by the employer. If an increase in vibration exposure or a change in health status have occurred, the medical re-examination should be offered at shorter intervals at the discretion of the attending physician. There should be a periodic medical examination, which includes recording any change in exposure to WBV. The findings for the individual should be compared with previous examinations. Group data should also be compiled periodically. Medical removal may be considered along with re-placement in working practices without exposure to WBV. This paper presents opinions on health surveillance for whole-body vibration developed within a working group of partners funded on a European Community Network (BIOMED2 concerted action BMH4-CT98-3251: Research network on detection and prevention of injuries due to occupational vibration exposures). The health surveillance protocol and the draft questionnaire with explanation comments are presented for wider consideration by the science community and others before being considered appropriate for implementation.     

金属卤化物中的晶格振动

运用紧束缚双带模型对MX化合物晶格振动的计算发现,晶格振动谱由一条声频支和三条光频支组成,进一步得到了出现元激发时,晶格振动色散关系中的分立频率和相应的定域振动模.在MX化合物红外吸收谱的计算中发现对应不同元激发红外谱具有不同的特征. 关键词： 电荷密度波 晶格振动 红外吸收     

受迫振动演示实验装置

本文叙述用示波器显示来演示受迫振动的实验装置，可直观地向学生展示受迫振动的幅频特性和相频特性。     

受迫振动的能量共振

通过对受迫振动系统的功能，势能和总能量的分析，推证了受迫振动系统能量共振的频率，并对其结果进行了分析讨论。     

双相滞热传导的振动现象

本文用解析的方法研究了双相滞热传导的振动现象,给出了热传导振动发生的条件.发现传热介质的尺寸越小,热扩散系数越大,易引发温度场的振动现象.     

MX络合物中的晶格零点振动

利用自洽重整化方法,研究了不同电-声藕合作用下MX络合物中晶格零点振动对电荷密度波(CDW)的影响。对聚乙炔,无论电-声耦合作用强弱,键序波(BOW)总存在。而对MX络合物,计算表明,量子起伏对CDW的削弱作用依赖于电-声耦合作用的强弱。当电-声耦合作用强时,CDW的削弱小;相反,当电-声耦合作用弱时,CDW削弱大,甚至几乎被破坏。这一差异来源于以下事实,即在弱电-声耦合λ情况下,聚乙炔中光学模声子频率随λ^1/2减小,而在MX络合物中光学模声子频率与其裸值ω₀差 关键词：