[en] The analytical model of finite plate stiffened by blocking mass under a point force is established. The structural response is derived by a combination of the modal method and the traveling wave method, and used for studying effect of blocking mass on energy transmission from the exciting plate to the receiving plate taking mean square velocity as evaluation index. The effect by the parameters of the blocking mass such as the mass ratio on energy transmission is discussed. It is shown that in low frequencies range, blocking mass can effectively impede vibration energy transmission when the rigidity of the blocking mass is considered and will enhance vibration energy transmission when its rigidity is neglected. And it is also found that in higher frequencies range the attenuation effect gets better with the increase of the mass ratio in the higher frequencies. (authors)

[en] Motional impedance of a plasmoid allows considerable absorption of energy even when its ohmic resistance tends to be negligible. Relevant expression for the motional impedance is derived and the physical significance of the results is discussed. It is also shown that the energy of the system is conserved, under the condition R = 0, where R is the external resistance of the circuit. (author)

[en] A perturbation theory for broadband impedance calculations has been developed, allowing evaluation of impedances for an accelerating structure of a rather arbitrary shape. General formulas are given for the longitudinal and transverse impedances. The method is checked by calculating impedances and comparing results with those for structures previously studied. Several new results, including impedance of a taper, are presented

[en] Soil mechanical impedance (M1) and matric potential can both root growth rate, modify rooting pattern and root diameter. Cotton seedlings are sensitive to the soil physical environment, particularly during early stages of growth. Soil matric potential and M1 effect on root biomass, axial root length and diameter, and the number and length of lateral roots in soil packed to penetration resistances (PR) of 0.1, 1.0, 1.1 and 1.2 Mpa (mega Pascal 10/sup 6/ Pascal), each at three matric potentials of-10,-100 and -500 kpa (kilopascal ) = 10/sup 3/ Pascal), were determined. Total root length were reduced by 29, 50 and 53% at impedance of 1.0, 1.1 and 1.2 Mpa, respectively, as compared to the control, whereas M1 of 1.2 Mpa resulted in 60% reduction in axial root length. A similar increase in diameter was caused by increasing mechanical impedance, while decreasing matric potential had little effect. Roots that were water stressed did not change their diameter but had a shorter axis and longer lateral length. In contrast, the impeded roots (PR=1.0, 1.1 and 1.2 MPa) had both a shorter axis and a smaller total length, but had increased diameter. These results not only illustrate the plasticity of root response to stress but also demonstrate how the response differs between different types of stresses. (author)

[en] This paper summarizes the progress gained in the last few years in our understanding of bulk and interface constant-phase-angle (CPA) behavior in electrode-electrolyte systems. It is now fairly well established that the interface constant-phase element originates from the fractal nature of the interface. The complex geometry gives rise to a fractal distribution of parallel current paths, and the competition between these paths results in the fractional power law behavior of the impedance across the interface. On the other hand, the early hope of relating the CPA exponent to the fractal dimension of the interface has been shown to be unattainable. Our understanding of the bulk CPA behavior, which is most prevalent in solid electrolytes, is only tentative. It is illustrated using a simple model that, under nonlinear dynamical laws that govern the flow of ions in the electrolyte, a current in the solid can generate a fractal distribution of vacancies which tend to impede the flow. The current is forced to negotiate a complex path through the solid, and the resulting fluctuation in path length and flow rate could be a source of the CPA behavior. 32 refs., 18 figs

[en] A summary is presented of experimental measurements of the noise performance of a high impedance, low noise amplifier system and best-fit values of four general parameters for a noise model are obtained. Comments are made on various methods of amplifier noise specification. (Auth.)

[en] The electromechanical impedance(EM)-based method detects local structural damages based on variations of electrical impedance signatures which are obtained from piezoelectric sensors bonded to the structure and excited in high frequency band. In this method, temperature changes may result in significant impedance variations and lead to erroneous diagnostic results of the structure. To tackle this problem, a new technique providing a 2-dimensional damage feature related to the temperature information is proposed to distinguish the structural damage from the undesirable temperature variation. For experimental tests to validate the proposed method, damages are introduced by bolt loosening to a bolt-jointed steel beam, and impedance signals are measured under varying temperature conditions through a piezoelectric sensor attached on the beam. A freely suspended piezoelectric sensor is additionally utilized to obtain temperature information indirectly from resistance signatures. From a relationship between the damage index (from a constrained sensor) and the temperature (from a freely suspended sensor or a temperature sensor), damages can be detected more clearly under varying temperature compared to other conventional approaches

[en] We report on a new method to determine the collision rates for ionization by means of pair collisions (Paarstoesse) and stepwise ionization, respectively. This method is based on the experimental and theoretical study of the dynamical behaviour (impedance behaviour) of the positive column of a low-current discharge at low pressure. (orig.)

[en] Electromagnetic composites have wide application in the functional devices. For the best performance of devices, the regulation of the electrical impedance has been being desired for the impedance matching in service. However, the keeping of impedance matching in service is quite challenging. In the present work, a mechanical method for tuning the electrical impedance of La_0.7Sr_0.3MnO₃/0.72Pb(Mg_1/3Nb_2/3)O₃−0.28PbTiO₃ (LSMO/PMN-PT) based on the nanocontact technique is proposed. It is found that the electrical impedance reduces with the increase of the nanocontact load. A linear relationship is found between the square of impedance magnitude and the inverse of nanocontact depth. Furthermore, a method for predicting the contact-depth-dependent impedance magnitude of LSMO/PMN-PT is proposed. (paper)

[en] We have developed a simulated load technique for estimating power dissipation and effective impedance of the discharge which is useful over a wide range of driver frequencies. This is used to calculate the power delivered to the plasma and plasma current for frequencies from 0.12 to 13.56 MHz. This technique allows an efficiency calibration curve to be made for a given match circuit which can be quickly applied to any new discharge condition to give match efficiency