Mechanically clamped state

If stress is kept constant this is called a mechanically free state. If, alternatively, the strain is kept constant this is spoken of as a mechanically clamped state. A similar terminology is sometimes used for the electrical situation (e.g. Cady 1964, p. 262). Keeping electric field strength constant is called electrically jree, while electrically clamped refers to the constancy of the electric flux density. Finally, keeping temperature constant is referred to as isothermal while the situation at constant entropy is called isentropic or adiabatic. 

Other common means for determining the direct d33 coefficients of bulk samples include Berlincourtstyle approaches. Berlincourt meters are available commercially from several sources. In most cases, the sample to be measured is mechanically clamped between jaws with pressures on the order of a few N. The charge output due to a small mechanical oscillation (forces 0.1-0.3N) is then determined. It is important to note that this technique is appropriate for measurements of bulk samples with stable domain states, only. Measurement accuracy is also better when highly resistive samples are used. 

The sprayed anodes are widely used in the United States for impressed current cathodic protection. Originally, the mesh anodes were mechanically clamped to the pile. In later versions, a GRP jacket containing the zinc mesh is attached to the pile and filled with gront after connecting the zinc to the reinforcement (Figure 7.6). All these systems and their performance in Florida are discussed in Kessler et al. (1995, 2002). 

The TM ions usually used for passive g-switching of infrared solid-state lasers include Cr" " (940-1100 nm range), (1.30-1.35 pm), and Co " (1.3-1.6 pm). Although aU these ions can be doped in cubic materials, i.e., Cr and in garnets and Co " in spinels, only Cr YAG ceramics have been reported for ceramic SA g-switches [37, 42, 132, 133]. The SA materials are usually used as components together with the Nd laser-active materials in the cavity. In this case, if the laser materials and the g-switch materials have a same host, such as Nd YAG lasers passively g-switched with Cr" YAG, the difference in refractive index between them should be very small, so that there is no reflection at the interface when the two materials are intimately joined. For single crystals, they can be either diffusively bonded or mechanically clamped. In contrast, when one or both of them... 

For a complete specification of mechanical compliances, it is necessary carefully to specify the conditions under which a given measurement is carried out thus, one must state not only whether it is 5 or T that is kept fixed, but also whether , or D, and whether, electrically free when D = 0, the crystal is said to be electrically clamped. The latter condition is not readily experimentally realized for details, interested readers are referred to Nye, (Oxford, 1957) Constancy of a components demands that the crystal be mounted so as to allow the strains to take place in as unhindered a fashion as possible the material is then mechanically free. Constancy of e components requires that, ideally, the crystal be firmly attached to a medium with infinite elastic stiffness the material is then mechanically clamped. 

J. E. Ashton, Clamped Skew Plates of Orthotropic Material Under Transverse Load, in Devebpments in Mechanics, Vol. 5, The Iowa State University Press, Ames, Iowa, 1969, pp. 297-306. 

Although there are a number of mechanisms in cells for buffering or sequestering Ca2+ to prevent untoward or inappropriate rises in [Ca2+]i( in the long term, it is the activity of plasma membrane transport processes that determines the steady-state [Ca2+]j. This is because the plasma membrane acts as a Ca2+ buffer of essentially infinite capacity. This results from in vivo clamping of the extracellular concentration of Ca2+ by dietary and endocrine mechanisms. In in vitro experiments, this results from incubation volumes very much larger than the cell volume. 

Polar Cell Systems for Membrane Transport Studies Direct current electrical measurement in epithelia steady-state and transient analysis, 171, 607 impedance analysis in tight epithelia, 171, 628 electrical impedance analysis of leaky epithelia theory, techniques, and leak artifact problems, 171, 642 patch-clamp experiments in epithelia activation by hormones or neurotransmitters, 171, 663 ionic permeation mechanisms in epithelia biionic potentials, dilution potentials, conductances, and streaming potentials, 171, 678 use of ionophores in epithelia characterizing membrane properties, 171, 715 cultures as epithelial models porous-bottom culture dishes for studying transport and differentiation, 171, 736 volume regulation in epithelia experimental approaches, 171, 744 scanning electrode localization of transport pathways in epithelial tissues, 171, 792. 

A switch-clamp-latch mechanism is critical for the quiescent state of c-ABL normally. The switch refers to a flip that occurs in an activation loop from the C-lobe that goes between opened and closed conformations and represent active and inactive states of the enz5mie, respectively (Fig. 2). This clamp or loop limits the access of ATP and other substrates to the active binding site of the ABLl protein. A latch stabilizes... 

In such a measurement, the sample is clamped as lightly as possible, and the displacement of the surface in monitored. The amount of sample clamping is important, because the mechanical constraints can impact the ferroelastic response of the sample. That is, in samples where the mechanical coercive stress is low, it is possible to change the domain state of the material by improperly clamping it in the sample fixture. This is especially important in elastically soft piezoelectrics, such as many of the relaxor ferroelectric PbTiC>3 single crystals. 

The next approximation is to clamp the nuclei at classically variable coordinates. This approximation still allows freedom to study the electron density quantum-mechanically. However, in view of the nature of the valence state developed here there is precious little to gain by attempting all-electron calculations. 

The switching between different conformational states results from physical processes in the channel protein. Thus, the patch clamp data is an important probe of the mechanisms that cause the channel protein to change its conformational state. We will review how the changing interpretations of the patch clamp data led to a new understanding of the mechanisms that open and close the ion channel. 

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