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A Fundamental Principles

It is a fundamental principle of quantum mechanics that electrons bound in an atom can have only discrete energy values. Thus, when an electron strikes an atom its electrons can absorb energy from the incident electron in specific, discrete amounts. As a result the scattered incident electron can lose energy only in specific amounts. In EELS an incident electron beam of energy Eq bombards an atom or collection of atoms. After the interaction the energy loss E of the scattered electron beam is measured. Since the electronic energy states of different elements, and of a single element in different chemical environments, are unique, the emitted beam will contain information about the composition and chemistry of the specimen. [Pg.325]

In Section 1.4 it was pointed out that a fundamental principle of corrosion is that the sum of the rates of the cathodic reactions must equal the sum of the rates of the anodic reactions, irrespective of whether the attack is uniform or localised ... [Pg.154]

Consider a physical system with a set of states a, each of which has an energy Hio). If the system is at some finite temperature T, random thermal fluctuations will cause a and therefore H a) to vary. While a system might initially be driven towards one direction (decreasing H, for example) during some transient period immediately following its preparation, as time increases, it eventually fluctuates around a constant average value. When a system has reached this state, it is said to be in thermal equilibrium. A fundamental principle from thermodynamics states that when a system is in thermal equilibrium, each of its states a occurs with a probability equal to the Boltzman distribution P(a) ... [Pg.326]

First, we shall explore a conceptual relation between kinetics and thermodynamics that allows one to draw certain conclusions about the kinetics of the reverse reaction, even when it has itself not been studied. Second, we shall show how the thermodynamic state functions for the transition state can be defined from kinetic data. These are the previously mentioned activation parameters. If their values for the reaction in one direction have been determined, then the values in the other can be calculated from them as well as the standard thermodynamic functions. The implications of this calculation will be explored. Third, we shall consider a fundamental principle that requires that the... [Pg.155]

It is therefore a fundamental principle in the estimation of every enzyme that the rates measured should be maximal initial reaction velocities, tangents to progress curves at zero time. They really should represent the amount of enzyme protein in the reaction mixture. [Pg.256]

The mixing of the sample and reagents in predetermined proportions rather than specific volumes is a fundamental principle of continuous flow analysis and is achieved by using a constant-speed roller bar peristaltic pump and flexible plastic delivery tubes of different internal diameters. These pump tubes are stretched between two plastic end-blocks, which hold them taut between a... [Pg.218]

FORMULA FOR POSIT IVITY-In the laws of MentaUsm there is a fundamental principle that the positive always dominates the negative—the negative is always subordinate to the positive. Everything has its keynote of positivity. And that keynote deoends noon the iltrrte oE Will—... [Pg.75]

A fundamental principle of reaction engineering is that we may be able to find a suitable catalyst that will accelerate a desired reaction while leaving others unchanged or an inhibitor that will slow reaction rates. We note the following important points about the relations between thermodynamics and kinetics ... [Pg.37]

A fundamental principle of quantum mechanics states that any physically observable quantity corresponds to a linear operator. [Pg.66]

D) The Heisenberg Uncertainty Principle says that it is impossible to determine the exact position and momentum of an electron at the same time. It is a fundamental principle of quantum mechanics. [Pg.49]

In 2003 the 55th World Health Assembly resolved (WHA resolution 55.18) as follows Recognizing the need to promote patient safety as a fundamental principle of all health systems, [The WHO] urges Member States ... [Pg.60]

It will be seen a little later that Homberg was not alone in his awareness of the conservation of weight principle. But it was not until nearly the end of the century, after adequate techniques for handling aeriform matter were developed, that Lavoisier verbalized it as a fundamental principle and utilized it systematically as a rigorous way of establishing quantitative composition. [Pg.87]

One of the most common ways to prepare a solution is to dilute a concentrated solution that has already been prepared. There is a fundamental principle that underlies all dilutions the number of moles of solute is the same after dilution as before. It is only the moles of solvent that have been changed (increased). This principle makes dilution calculations simple. If M, and M2 are tjje molarities before and after dilution, and V, and are the initiai and final volumes of solution, then... [Pg.193]

NOTE In practice, when taking over a new water treatment program account, it is almost impossible for a field representative to know the full history and engineering details of the cooling system(s). As a consequence, a survey involves considerably more than merely filling in a standard company survey sheet. Some degree of investigation is required, relevant to the size and complexity of the plant. In addition, it is a fundamental principle that in the early days of a new account contract the water treatment company personnel will spend considerable time on-site so as to be fully conversant with the plant and operator practices. [Pg.252]

An unexpected and much more disturbing result, however, is how managing DG Sanco officers tried to control the publication of this study, indeed the very words we have written here. As noted, contrary to our explicit request (and in violation of a fundamental principle in scientific publishing), these DG Sanco officers not only disseminated a draft of this article to at least one other EU officer and some of the... [Pg.315]

Lucretius could have meant this as a fundamental principle of the best packing arrangements for molecules in crystals had he known... [Pg.457]

Receptor pre-assembly has also been described for other receptor families and appears to be a fundamental principle for the signal transduction of oligomeric receptors. For example, the insulin receptor is a... [Pg.265]

A fundamental principle derived from the structural studies of TRAF-receptor complexes is that although the interactions are of low affinity, they are highly specific as shown by the identical interactions in different crystal packing environments and with different lengths of receptor peptides. This is in contrast to low affinity non-specific protein-DNA interactions that are mediated solely by charge attractions. [Pg.269]

The mechanical energy balance is not a fundamental principle rather, it is a corollary (Bird 1957 Bird. Stewart, and Lightfoot 2002) of the equation of motion. For constant fluid density, the macroscopic mechanical energy balance takes the form... [Pg.42]

The arguments put forward by G. Kelling (1923) apply just as much today as they did in the past - exploratory laparoscopy of the abdominal cavity is one of the most important aims of laparoscopy. (246) (s. tab. 7.12) In working towards a diagnosis, it is a fundamental principle that exploratory laparoscopy should be given priority over exploratory laparotomy. (197, 205, 213, 215, 218, 227, 245, 253, 254, 277, 293, 294, 315)... [Pg.150]


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A fundamentals

Fundamental principles

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