Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Advanced definition

Indeed it seems hardly likely that much progress can be made in the solution of the difficult problems relating to chemical combination by assigning in advance definite laws of force between the positive and... [Pg.360]

For the Berry phase, we shall quote a definition given in [164] ""The phase that can be acquired by a state moving adiabatically (slowly) around a closed path in the parameter space of the system. There is a further, somewhat more general phase, that appears in any cyclic motion, not necessarily slow in the Hilbert space, which is the Aharonov-Anandan phase [10]. Other developments and applications are abundant. An interim summai was published in 1990 [78]. A further, more up-to-date summary, especially on progress in experimental developments, is much needed. (In Section IV we list some publications that report on the experimental determinations of the Berry phase.) Regarding theoretical advances, we note (in a somewhat subjective and selective mode) some clarifications regarding parallel transport, e.g., [165], This paper discusses the projective Hilbert space and its metric (the Fubini-Study metric). The projective Hilbert space arises from the Hilbert space of the electronic manifold by the removal of the overall phase and is therefore a central geometrical concept in any treatment of the component phases, such as this chapter. [Pg.105]

General Electric Co., Definition of the Development Program fioran MHD Advanced PowerTrain, DOE Report No. DE-AC22-83PC60574, U.S. Department of Energy, Washington, D.C., Dec. 1984. [Pg.438]

The fundamental parameters in the two main methods of achieving ignition are basically the same. Recent advances in the field of combustion have been in the development of mathematical definitions for some of these parameters. For instance, consider the case of ignition achieved by means of an electric spark, where electrical energy released between electrodes results in the formation of a plasma in which the ionized gas acts as a conductor of electricity. The electrical energy Hberated by the spark is given by equation 2 (1), where V = the potential, V 7 = the current. A 0 = the spark duration, s and t = time, s. [Pg.516]

L. Rcimer. Scanning Electron Microscopy. Springer-Verlag, Berlin, 1985. An advanced text for experts, this is probably the most definitive work in the field. [Pg.84]

In spite of numerous advances in the field of detection there are not and never have been any genuinely substance-specific chemical detection reactions. This means that, unlike the spectrometric methods, the methods of detection normally employed in chromatography cannot be employed for an unequivocal identification of compounds, they can only provide more or less definite indications for the characterization of the separated substances. Universal reagents are usually employed for a first analysis of the separation of samples of unknowns. This is then followed by the use of group-specific reagents. The more individual the pieces of information that can be provided from various sources for a presumed substance the more certainly is its presence indicated. However, all this evidence remains indicative it is not a confirmation of identity. [Pg.4]

A recent definition of catalysis that is based on dier-modynamics was advanced by the Subcommittee on Chemical Kinetics, Physical Chemistry Division, lUPA ... [Pg.225]

Cayley has advanced the computation of and to an impressive degree. The definition of ignoring the notion of root, is simpler than that of However, we will see that, from an analytical point of view, is easier to handle than can be derived... [Pg.4]

Our starting point will be based on examples of the activities of science, rather than on definitions. We will perform these activities, beginning on familiar ground. On such ground, where you know the answer, you will best see the steps by which science advances. [Pg.1]

The value of the second (conceptual) definition is that it contains more information about stardom. If accurate, it has the deeper significance. It might help the basketball coach more in developing the optimum characteristics of his squad. It permits him to predict athletic skill in advance of the first game. [Pg.195]

It is idle to pretend that a definite comparison of optical (ultraviolet, visible, and infrared) emission spectrography with x-ray emission spectrography can be made at this time. We give in Table 8-4, with little qualification and no defense, what we consider to be a fair comparison for a laboratory called upon to determine a large number of elements under a variety of conditions not necessarily known in advance. [Pg.237]

The problem with the Arrhenius definitions is that they are specific to one particular solvent, water. When chemists studied nonaqueous solvents, such as liquid ammonia, they found that a number of substances showed the same pattern of acid-base behavior, but plainly the Arrhenius definitions could not be used. A major advance in our understanding of what it means to be an acid or a base came in 1923, when two chemists working independently, Thomas Lowry in England and Johannes Bronsted in Denmark, came up with the same idea. Their insight was to realize that the key process responsible for the properties of acids and bases was the transfer of a proton (a hydrogen ion) from one substance to another. The Bronsted-Lowry definition of acids and bases is as follows ... [Pg.97]

Practical activities should embody as best as possible the scientifie proeesses that have been preseribed by the American Association for the Advancement of Science observation, elassification, numerieal relations, measurements, time-spaee relations, eommunieation (oral, pictorial, written), deriving of conclusions, prediction ( what would happen if. .hypothesis making, production of operational definitions, identifieation and control of variables, experiment and explanation of experimental data. Different theoretical perspectives should be used with the aim to optimize the positive eognitive and affeetive outcomes. The use, sometimes together, sometimes separately, of different perspeetives can act complimentarily and can lead to positive results (Niaz, 1993 Tsaparhs, 1997). [Pg.129]

Several aspects of AFM and its applications to rubbery materials were discussed and illustrated in this chapter. Despite a definite advance in this field during the last 10 years, there is plenty of room for more improvement of this method that will further broaden its use. In conclusion, we would like to mention several future capabilities. [Pg.576]


See other pages where Advanced definition is mentioned: [Pg.180]    [Pg.857]    [Pg.117]    [Pg.11]    [Pg.994]    [Pg.141]    [Pg.16]    [Pg.180]    [Pg.857]    [Pg.117]    [Pg.11]    [Pg.994]    [Pg.141]    [Pg.16]    [Pg.361]    [Pg.231]    [Pg.3]    [Pg.26]    [Pg.274]    [Pg.429]    [Pg.397]    [Pg.26]    [Pg.531]    [Pg.261]    [Pg.122]    [Pg.177]    [Pg.107]    [Pg.1034]    [Pg.380]    [Pg.610]    [Pg.807]    [Pg.492]    [Pg.272]    [Pg.88]    [Pg.387]    [Pg.352]    [Pg.29]    [Pg.279]    [Pg.30]    [Pg.62]    [Pg.576]    [Pg.749]   
See also in sourсe #XX -- [ Pg.148 ]




SEARCH



© 2024 chempedia.info