Field principle

Fuhr G, Zimmermann U, Shirley SG (1996) Cell motion in time-varying fields principles and potential. In Zimmermann U, Neil GA (eds) Electromanipulation of cells. CRC Press, Boca Raton, p 259... 

Szabo, I. (1986) New ion optical devices utilizing oscillatory electric fields principle of operation and analytical theory of multipole devices with two dimensional electric fields. Int. J. Mass Spectrom. Ion Process. 73, 197-235. 

Assfeld X, Ferre N, Rivail JL. The local self consistent field. Principles and applications to combined QM/MM computations on biomacromolecular systems. In Gao J, Thompson MA, eds. Combined Quantum Mechanical and Molecular Mechanical Methods. ACS Symposium Series 712. Washington, DC American Chemical Society, 1998 234-239. 

Probability and statistics are two interconnected fields within applied mathematics. In both fields, principles of scientific theory are applied to the analysis of groups of data in the form of numbers. The main objective of probability and statistics is to ask and answer questions about data with as much accuracy as possible. 

Haufiecker, H., Reinelt, S., and Jahne, B. 1995. Heat as a proxy tracer for gas exchange measurements in the field Principle and technical realization. In Air-Water Gas Transfer. B. Jahne and E. C. Monahan (Eds). Aeon Verlag, Hanau, Germany, 405. 

Introduction Overview of the Field Principles of Bioreactor Design Microscale Technologies Cardiac Tissue Engineering Bioreactors Vascular... 

Whether on land or offshore, the principle of satellite development is the same. A new field is accessed with wells, and an export link is installed to the existing (host) facility. Development is not always easier on land, as environmental restrictions mean that some onshore fields have to be developed using directional drilling techniques (originally associated with offshore developments). A vertical well can be drilled offshore away from the host facility, and the well completed using a subsea wellhead. 

The principle physical phenomenon of applying the eddy current method for evaluating the amount of residual austenite in the structure of quenched steel is magnetic induction, involving the influence of the changeable magnetic field on the studied area, found under the probe. 

Fig. 1. A diagram of the principle of the contact probe during the study of the metal matenal structure Ho - field produced by the probe, Hp - field ensuring the measuring signal, Hw - field produced by eddy currents.

Principle of the Remote Field Eddy Current Technique... 

For the determination of the approximated solution of this equation the finite difference method and the finite element method (FEM) can be used. FEM has advantages because of lower requirements to the diseretization. If the material properties within one element are estimated to be constant the last term of the equation becomes zero. Figure 2 shows the principle discretization for the field computation. 

P.D. Wilcox, R.S.C. Monkhouse, M.J.S. Lowe and P. Cawley, The use of Huygens principle to model the acoustic field from interdigital Lamb wave transducers, Review of Progress in Quantitative NDE, Vol 17, Plenum Press, New York, 1998 (in press). 

In principle any PC can be used, provided it has the necessary computing power and memory installed and can be equipped with the processor board, which requires an empty PCI slot in the PC. For using the system in the field, it is recommended to use an industrial PC, designed to be used in a harsh environment. 

The positive results and savings due to use of NDT and TD are hundred times grater than made investments. This is the main reason why the philosophy of safety management was changed, i.e. from the philosophy to react and correcf to the principle to predict and reduce the losses . The use of NDT and TD allows to foresee the results of economic-technical activity, to make mostly efficient decisions, to reduce the risks, to simulate mutual processes relations in technogenic, ecological and social-economical fields. 

Conventional covermeters operating on the principle of electro-magnetic fields are capable of determining depth of cover to reinforcement down to about 100 mm with an accuracy of 5 % provided the bar diameter is known and the spacing between individual bars is greater than about 150 mm. If bars are spliced then the covermeter will underestimate the cover depth. 

The idea that unsymmetrical molecules will orient at an interface is now so well accepted that it hardly needs to be argued, but it is of interest to outline some of the history of the concept. Hardy [74] and Harkins [75] devoted a good deal of attention to the idea of force fields around molecules, more or less intense depending on the polarity and specific details of the structure. Orientation was treated in terms of a principle of least abrupt change in force fields, that is, that molecules should be oriented at an interface so as to provide the most gradual transition from one phase to the other. If we read interaction energy instead of force field, the principle could be reworded on the very reasonable basis that molecules will be oriented so that their mutual interaction energy will be a maximum. 

Equation XVII-127 connects the functions 0(F, T), d(Q,P, T) and f Q) and, in principle, if any two are known or can be assumed, the remaining one can be calculated. As may be imagined, many choices of such pairs of functions have been examined, often designed so that Eq. XVII-127 can be handled analytically alternatively, various schemes of successive approximations may be used. The field has become somewhat of a happy hunting ground for physical chemists and there are numerous reviews of the now-extensive literature (see Refs. 144-147 the last is a personalized account). For this reason only some generic approaches will be discussed here. 

Semiconductors are poor conductors of electricity at low temperatures. Since the valence band is completely occupied, an applied electric field caimot change the total momentum of the valence electrons. This is a reflection of the Pauli principle. This would not be true for an electron that is excited into the conduction band. However, for a band gap of 1 eV or more, few electrons can be themially excited into the conduction band at ambient temperatures. Conversely, the electronic properties of semiconductors at ambient temperatures can be profoundly altered by the... 

As described at the end of section Al.6.1. in nonlinear spectroscopy a polarization is created in the material which depends in a nonlinear way on the strength of the electric field. As we shall now see, the microscopic description of this nonlinear polarization involves multiple interactions of the material with the electric field. The multiple interactions in principle contain infomiation on both the ground electronic state and excited electronic state dynamics, and for a molecule in the presence of solvent, infomiation on the molecule-solvent interactions. Excellent general introductions to nonlinear spectroscopy may be found in [35, 36 and 37]. Raman spectroscopy, described at the end of the previous section, is also a nonlinear spectroscopy, in the sense that it involves more than one interaction of light with the material, but it is a pathological example since the second interaction is tlirough spontaneous emission and therefore not proportional to a driving field... 

Because surface science employs a multitude of teclmiques, it is necessary that any worker in the field be acquainted with at least the basic principles underlying tlie most popular ones. These will be briefly described here. For a more detailed discussion of the physics underlymg the major surface analysis teclmiques, see the appropriate chapter m this encyclopedia, or [49]. 

State I ) m the electronic ground state. In principle, other possibilities may also be conceived for the preparation step, as discussed in section A3.13.1, section A3.13.2 and section A3.13.3. In order to detemiine superposition coefficients within a realistic experimental set-up using irradiation, the following questions need to be answered (1) Wliat are the eigenstates (2) What are the electric dipole transition matrix elements (3) What is the orientation of the molecule with respect to the laboratory fixed (Imearly or circularly) polarized electric field vector of the radiation The first question requires knowledge of the potential energy surface, or... 

Unlike the typical laser source, the zero-point blackbody field is spectrally white , providing all colours, CO2, that seek out all co - CO2 = coj resonances available in a given sample. Thus all possible Raman lines can be seen with a single incident source at tOp Such multiplex capability is now found in the Class II spectroscopies where broadband excitation is obtained either by using modeless lasers, or a femtosecond pulse, which on first principles must be spectrally broad [32]. Another distinction between a coherent laser source and the blackbody radiation is that the zero-point field is spatially isotropic. By perfonuing the simple wavevector algebra for SR, we find that the scattered radiation is isotropic as well. This concept of spatial incoherence will be used to explain a certain stimulated Raman scattering event in a subsequent section. 

The principles of operation of quadnipole mass spectrometers were first described in the late 1950s by Wolfgang Paul who shared the 1989 Nobel Prize in Physics for this development. The equations governing the motion of an ion in a quadnipole field are quite complex and it is not the scope of the present article to provide the reader with a complete treatment. Rather, the basic principles of operation will be described, the reader being referred to several excellent sources for more complete infonnation [13, H and 15]. 

The principal dilTerence from liquid-state NMR is that the interactions which are averaged by molecular motion on the NMR timescale in liquids lead, because of their anisotropic nature, to much wider lines in solids. Extra infonnation is, in principle, available but is often masked by the lower resolution. Thus, many of the teclmiques developed for liquid-state NMR are not currently feasible in the solid state. Furthemiore, the increased linewidth and the methods used to achieve high resolution put more demands on the spectrometer. Nevertheless, the field of solid-state NMR is advancing rapidly, with a steady stream of new experiments forthcoming. 

For quadnipolar nuclei, the dependence of the pulse response on Vq/v has led to the development of quadnipolar nutation, which is a two-dimensional (2D) NMR experiment. The principle of 2D experiments is that a series of FIDs are acquired as a fimction of a second time parameter (e.g. here the pulse lengdi applied). A double Fourier transfomiation can then be carried out to give a 2D data set (FI, F2). For quadnipolar nuclei while the pulse is on the experiment is effectively being carried out at low field with the spin states detemiined by the quadnipolar interaction. In the limits Vq v the pulse response lies at v and... 

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