共查询到19条相似文献,搜索用时 343 毫秒
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测量杨氏模量的方法很多,如静态拉伸法、梁的弯曲法等.通常当采用静态拉伸法测量金属丝做小的伸长量时,应用了光杠杆的放大原理.测量装置如图1所示. 相似文献
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利用大学物理实验中的光杠杆法测定金属丝弹性模量的原理和设备,对具有超弹性的NiTi丝的弹性滞后环进行了测定结果表明,此种方法可以很好地测定NiTi丝的弹性滞后环,而且操作简单使用方便,是一种非常有效的测定金属细丝弹性滞后环的方法. 相似文献
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光的衍射法测量杨氏模量 总被引:1,自引:0,他引:1
拉伸法测量金属丝杨氏模量的关键是如何测准金属丝在拉力作用下的微小伸长量。本文利用光的衍射法可以较精确地测量长度变化这一特点,对钢丝的杨氏模量进行了测量,给出测量杨氏模量的一种新方法。 相似文献
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金属丝在拉伸力的作用下长度会发生微小变化,金属丝长度的微小变化会使其电阻同时发生微小改变,利用双臂电桥测量低阻值电阻的原理测金属丝电阻的微小变化量,再通过相应的公式求得被测金属丝的杨氏模量,该方法简便,测量准确. 相似文献
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利用电加热方法实现金属丝温度变化,利用数字显微镜测量金属丝在不同温度和拉力情况下准确的拉伸长度数值,最终计算得到的金属丝杨氏模量和温度之间成线性递减关系。 相似文献
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Iulian PetrilaAlexandru Stancu 《Physica B: Condensed Matter》2011,406(4):906-910
The analytical way to describe uniaxial single-domain particles, using new symmetry considerations on the magnetic anisotropy, as a vector hysteresis unit (vector hysteron), is presented. The main characteristics of the vector hysteron such as the longitudinal hysteresis loops, transversal hysteresis loops and rotational hysteresis loops are presented. An extension of the vector hysteron and a vector hysteron that can be applied to the ferroelectric hysteresis are also presented. 相似文献
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A novel and simple approach based on transformation using neural networks is proposed in this paper to model the inverse behavior of hysteresis. In this approach, a continuous transformation is used to construct an elementary inverse hysteresis operator (EIHO), which can extract the change tendency of inverse hysteresis. Then based on the EIHO, an expanded input space is constructed to transform the multi-valued mapping of inverse hysteresis into a one-to-one mapping. Based on the constructed expanded input space, a neural network is employed to approximate the inverse hysteresis. Both experiment and simulation are implemented to validate the effectiveness of the proposed approach. These results indicate that the proposed approach has derived satisfactory modeling performance. 相似文献
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《Current Applied Physics》2020,20(2):298-303
The hysteresis in the transfer curve of MoS2 has significant impact on the device performance. However, the hysteresis mechanism is still not clear. Here, we investigate the hysteresis of the monolayer MoS2 by probing the local Fermi level variations as a function of the back gate voltage in different atmosphere using the Kelvin probe microscopy. While the Fermi level of the MoS2 in air is much lower than that in vacuum, both the MoS2 devices in vacuum and air show large Fermi level hysteresis. The Fermi level hysteresis direction is clock-wise, identical to that observed in the transfer curves. Both the hysteresis in Fermi level and transfer curve can be explained consistently by taking into account the charge trapping. Our findings confirm that carrier density modulation in MoS2 plays a vital role in the hysteresis, and provide insight into the hysteresis mechanism for the optimization of the device performance. 相似文献
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We study a hysteresis phenomenon in a rotating BEC with a weak link in a quasi-one-dimensional torus by proposing a microscopic theoretical model including a dissipation bath. By analyzing the role of dissipation and the decay rates of all the energy levels, we are able to give a microscopic interpretation of hysteresis recently observed in the experiment and confirm that the hysteresis is the result of the presence of metastable state. In particular, we obtain the hysteresis loops in a quench process just as that in the experiment. We also find that the shape and size of the hysteresis loop change drastically with the strength of the link. 相似文献
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We introduce a new class of time dependent hysteresis models by combining the time dependent Prandtl–Ishlinskii model with functional nonlinearities. This combination improves the capability of the time dependent Prandtl–Ishlinskii model to characterize a class of complex time dependent hysteresis nonlinearities in smart actuators. The analytical inversion for the proposed time dependent hysteresis model is also presented in order to extend the inversion algorithm of the inverse time dependent Prandtl–Ishlinskii model for a class of complex time dependent hysteresis nonlinearities. 相似文献
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Observation of zero creep in piezoelectric actuators 总被引:1,自引:0,他引:1
K.R. Koops P.M.L.O. Scholte W.L. de Koning 《Applied Physics A: Materials Science & Processing》1999,68(6):691-697
Piezoelectric actuators are frequently used nowadays in a wide variety of positioning devices. Although very suitable for
small displacements in the range of nm to several hundreds of μm, the actuators always suffer from hysteresis and creep between
the input voltage and resulting displacements. In scanning applications, the input voltage is often used as an indicator of
the induced displacement. This procedure can result in a large position error depending on the amount of hysteresis and creep.
In order to describe and control hysteretic systems various models for hysteresis have been published but little is known
about relaxation and creep in piezo materials. In this paper we present detailed studies of the hysteretic behavior and piezo
relaxation and creep. We have identified certain locations on the hysteresis loop that exhibit zero creep. From this observation,
a more fundamental relation between the amount of creep and the local slope of the hysteresis loop and the virgin curve is
presented. This observation could be useful in both open-loop and closed-loop position control, since it allows quantification
of the creep. Futhermore, the experimentally observed relation between the creep and the hysteresis suggests a reduction of
the creep for non-hysteretic transfers. First measurements on a system with reduced hysteresis support this hypothesis.
Received: 15 February 1999 / Accepted: 16 February 1999 / Published online: 28 April 1999 相似文献
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The position of an interface (domain wall) in a medium with random pinning defects is not determined unambiguously by the instantaneous value of the driving force, even on average. Employing the general theory of the interface motion in a random medium, we study this hysteresis, different possible shapes of the hysteresis loop, and the dynamical phase transitions between them. Several principal characteristics of the hysteresis, including the coercive force and the curves of dynamical phase transitions obey scaling laws and display a critical behavior in the vicinity of the mobility threshold. At finite temperature the threshold is smeared and a new range of thermally activated hysteresis appears. At a finite frequency of the driving force there exists a range of the non-adiabatic regime in which not only the position, but also the average velocity of the domain wall, displays hysteresis. 相似文献