scholarly journals The "action" of an electromagnetic field

1928 ◽  
Vol 120 (786) ◽  
pp. 483-502 ◽  
Keyword(s):  
Electromagnetic Field ◽  
Total Energy ◽  
Extreme Value ◽  
Natural System ◽  
Degree Of Freedom ◽  
The Other ◽  
Material System ◽  
Least Action ◽  
The One ◽  
Special Circumstances

Variation Principles in Dynamics and in the Electromagnetic Field.—In the dynamics of a material system the name "action" is given to two different quantities. One of these is S = Ʃ r ∫ q'' r q1 s p r dq r = Ʃ r ∫ t'' t ' p r q r dt , q r , p , being the co-ordinate and momentum associated with the r th degree of freedom, and the integral being extended from one definite set of values of the q r 's, to another. The other is A = ∫ t'' t ' (Ʃ r ) p r q r —H) dt , where H (except in special circumstances) is in conservative systems the total energy, and the integral is taken between two definite times t ' and t ''. Corresponding to S and to A, there are two distinct principles of "least action." Among the group of imaginary systems produced by varying the p r and q r under specified conditions in each case, on the one hand the S and on the other the A, of the "natural" system which obeys the laws of dynamics, possesses an extreme value.

Growth and Characterization of Inas Quantum Dots on Silicon

1999 ◽  
Vol 583 ◽  
Author(s):  
L. Hansen ◽  
A. Ankudinov ◽  
F. Bensing ◽  
J. Wagner ◽  
G. Ade ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
The Other ◽  
Material System ◽  
Inas Quantum Dots ◽  
New Material ◽  
The One ◽  
Insight Into

AbstractUp to 1011 cm−2 InAs quantum dots (QD) can be grown on Silicon(001) by molecular beam epitaxy. This very new material system is on the one hand interesting with regard to the integration of optoelectronics with silicon technology on the other hand it offers new insight into the formation of QDs. We report on RHEED, TEM and Raman studies about (in-) coherence of the QDs and on an according to our knowledge so far unknown dewetting transition in this material system. The results are being discussed on the basis of a thermodynamic model, assuming a liquid-like behavior of a strained adlayer.

scholarly journals Życiorysy czytelnicze zarys koncepcji

2018 ◽  
Vol 61 ◽  
pp. 227-239
Author(s):  
Jiří Trávníček
Keyword(s):  
Czech Republic ◽  
Social Context ◽  
Life Stories ◽  
Degree Of Freedom ◽  
The Other ◽  
The Czech Republic ◽  
Professional Groups ◽  
Statistical Surveys ◽  
The One

ŻYCIORYSY CZYTELNICZE ZARYS KONCEPCJIProjekt badawczy życiorysów czytelniczych — jego zaplecze i rezultaty, stosunek do biografistyki. Myślenie narracyjne i lektura, opowieść biografi czna. Potencjał życiorysów czytelniczych.LIFE STORIES OF READERS AN OUTLINE OF A CONCEPTBetween 2007 and 2013 the author carried out extensive statistical surveys of reading in the Czech Republic, the results of which were published successively in 2008, 2011 and 2014. At the same time, between 2009 and 2015 he collected 138 life stories of readers from across the country, representative of the various generations as well as social and professional groups. This material has made it possible to distinguish and describe four generations of readers: 15–24, 25–44, 45–64 and over 65, and to point to key phenomena concerning Czech readers — specific works and authors as well as attitudes to reading in general.The concept of life stories, a unique variety of biographies, on the one hand is based on a chronological interview script, the objective of which is to reconstruct the development of specific readers, and on the other it provides for a degree of freedom and spontaneity of expression, which also reveal an emotional attitude to reading. Another important feature is a strong historical and social context of reading across society. Sources produced as a result significantly complement typical memoirs and letters, which feature reading-related themes, as well as statistical surveys.

scholarly journals On Tubes of Force in a special class of electromagnetic fields

1922 ◽  
Vol 41 ◽  
pp. 100-107
Author(s):  
G. S. Eastwood
Keyword(s):  
Electromagnetic Field ◽  
Electromagnetic Fields ◽  
Electromagnetic Force ◽  
Special Class ◽  
Royal Society ◽  
Space Time ◽  
The Other ◽  
Family Meeting ◽  
The One

Professor Whittaker, in a paper entitled “On Tubes of Electromagnetic Force” {see Proceedings of the Royal Society of Edinburgh, Vol. XLII., Part I. (No 1)}, introduces certain surfaces, which he names calamoids, in connection with an electromagnetic field in the four-dimensional world of space-time. The calamoids consist of “a convariant family of surfaces which when the field is purely electrostatic or purely magnetostatic reduce to the ordinary Faraday tubes of force.” Professor Whittaker, in the paper referred to, also introduces two sets of surfaces, each a covariant family of ∞2 surfaces, one of them named the electropotential surfaces, and the other family the magnetopotential surfaces of the electromagnetic field. The electropotential surfaces and the magnetopotential surfaces are shown to be everywhere absolutely orthogonal. (One member of each family meeting at a point, any line from this point in the one family is orthogonal to every line through the point in the other family). Moreover, a “calamoid, at every one of its points, is half-parallel and half-orthogonal to the electropotential surface which passes through the point, and is also half-parallel and half-orthogonal to the magnetopotential surface which passes through the point.”

scholarly journals The digestibility of straw after treatment with soda

1920 ◽  
Vol 10 (4) ◽  
pp. 437-456 ◽  
Author(s):  
William Godden
Keyword(s):  
Total Energy ◽  
Wheat Straw ◽  
Effective Action ◽  
The Other ◽  
Other Hand ◽  
Maize Meal ◽  
Oat Straw ◽  
The One ◽  
High Degree

The use of straw as fodder is beset by the double difficulty that on the one hand its bulky character seriously limits the extent to which it can be consumed by the animal, whilst on the other hand its tough and fibrous nature entails such a heavy expenditure of energy to secure the high degree of comminution and further preparation essential for effective action of the digestive agents that only a comparatively small surplus of energy remains over to serve productive nutritional ends. Thus it was found by Kellner and Köhler in the case of oat straw that of the total energy contained in the straw only 35·8 per cent, was usefully digested, whilst only 12·9 per cent, could be applied after digestion to productive purposes. For wheat straw the corresponding proportions were 31·1 per cent, and 5·5 per cent, respectively. These may be contrasted with the proportions of 49 per cent, and 20·7 per cent, respectively found by the same observers for meadow hay; and the proportions of 74·9 per cent, and 45·9 per cent, respectively found by Armsby and Fries for maize meal.

scholarly journals Comparison between XY Spin Chains with Spin 1/2 or 1 Interacting with Quantized Electromagnetic Field by One and Two Photon Jaynes-Cummings Model

2020 ◽  
Vol 7 (1) ◽  
pp. 4
Author(s):  
Hristo Tonchev
Keyword(s):  
Electromagnetic Field ◽  
Spin Chains ◽  
The Other ◽  
Field Mode ◽  
Two Photon ◽  
Quantized Electromagnetic Field ◽  
A Chain ◽  
The One ◽  
Block Structures ◽  
Jc Model

This paper describes two cases of interaction between a quantized electromagnetic field and two different XY spin molecules; one with spins ½, and the other with spins 1. Both interact with a quantized electromagnetic field, with one of the spins in the chain interacting with the electromagnetic field. The interaction between the field mode and the spin chain with spins 1 is described by the one- and two-photon Jaynes-Cummings model (JC model). On the other hand, the interaction between the spins ½ and the electromagnetic field is described only by the one-photon Jaynes-Cummings model. Analytical and numerical calculations were made for the case of a different number of photons in the field mode, a different number of spins, and a different position of spin, interacting with the electromagnetic field. The invariant and block structures of such a chain are shown with a comparison made between the evolution of the magnetic moment and the number of photons in both cases.

That Person Should Be the Next President Who…

Worldview ◽  
1976 ◽  
Vol 19 (1-2) ◽  
pp. 4-6
Author(s):  
Robert Coles ◽  
Theodore M. Hesburgh ◽  
Herbert Scoville
Keyword(s):  
Middle Class ◽  
Economic System ◽  
Political Institutions ◽  
Degree Of Freedom ◽  
The Other ◽  
Severe Stress ◽  
The Poor ◽  
Working People ◽  
The Rich ◽  
The One

That person should be the next President who is wilting to make a major issue of who owns what in our economic system. I am not saying that a candidate who is interested in explicitly and candidly analyzing our economic system stands a good chance of being nominated, let alone being elected President. I am simply saying that for me one of the major problems confronting this nation is the enormous disparity between the rich and the upper middle class on the one hand and, on the other, the working people and the poor, who make up the overwhelming majority of our people. I value this country's political institutions; they are not to be dismissed lightly. They are imperfect and have recently been subjected to severe stress. But they offer each of us a precious degree of freedom.

scholarly journals The monaural threshold: effect of a subliminal contralateral stimulus

1938 ◽  
Vol 124 (837) ◽  
pp. 406-420 ◽  
Keyword(s):  
Total Energy ◽  
Frequency Standard ◽  
Threshold Effect ◽  
The Other ◽  
Threshold Intensity ◽  
Frequency Range ◽  
Similar Frequency ◽  
The One ◽  
Loudness Scale ◽  
Contralateral Stimulus

It has been assumed by some workers that the intensity of a note of any frequency in either ear at the binaural threshold is one-half of the threshold intensity in either ear when used alone, i.e. at the monaural threshold. Another form of the assumption is the statem ent that the monaural threshold intensity is 3.0 db. above the intensity in either ear at the binaural threshold. In the course of the investigation of the possibility of forming a loudness scale, Churcher (1935), and Fletcher and Munson (1933), have found that the intensity of a note when heard binaurally may be assumed to be onehalf of that of the same note heard monaurally when the note is judged to be equally loud under the two conditions of listening. In the present work, this fact has been further verified. The measurements were extended to the cases in which the subliminal note presented to the one ear w’as maintained at various levels below the monaural threshold, and the intensity of the note applied to the other ear to reach the “ binaural” threshold was determined. In this way it was possible to find the relation between the energy required at the monaural threshold and the total energy required at the “binaural” threshold determined under these conditions. The experiments were also carried out with notes of different frequencies in the two ears in an endeavour to investigate the variations of total energy in such cases. Two heterodyne oscillators were used to provide pure notes of the various frequencies used during the work. The first of these (oscillator A ) was already available, and has been described elsewhere (Shaxby and Gage 1932); the second (oscillator B ) was a commercial oscillator of similar frequency range, viz. 30-10,000 c./sec. A , if allowed to run for about an hour, was very stable in frequency, varying by only 1 or 2 c./sec. during the next 7 hr. B drifted for about 2 hr. fairly rapidly, and thereafter drifted quite steadily at the rate of 10-15 c./sec. every hour. A was therefore used as the frequency standard. It was adjusted to read correctly by the “zerobeat” method after the “settling down” period, and set to the particular frequency required; B was brought into unison with it. The actual frequency of B could be determined in this way at any time, and its drift checked.

scholarly journals Remarks on Distance Based Topological Indices for ℓ-Apex Trees

Symmetry ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 802
Author(s):  
Martin Knor ◽  
Muhammad Imran ◽  
Muhammad Kamran Jamil ◽  
Riste Škrekovski
Keyword(s):  
Graph Theory ◽  
Wiener Index ◽  
Extreme Value ◽  
Topological Indices ◽  
The Other ◽  
Harary Index ◽  
Open Questions ◽  
Degree Distance ◽  
The One ◽  
Extremal Values

A graph G is called an ℓ-apex tree if there exist a vertex subset A ⊂ V ( G ) with cardinality ℓ such that G − A is a tree and there is no other subset of smaller cardinality with this property. In the paper, we investigate extremal values of several monotonic distance-based topological indices for this class of graphs, namely generalized Wiener index, and consequently for the Wiener index and the Harary index, and also for some newer indices as connective eccentricity index, generalized degree distance, and others. For the one extreme value we obtain that the extremal graph is a join of a tree and a clique. Regarding the other extreme value, which turns out to be a harder problem, we obtain results for ℓ = 1 and pose some open questions for higher ℓ. Symmetry has always played an important role in Graph Theory, in recent years, this role has increased significantly in several branches of this field, including topological indices of graphs.

Note on Selection of Coordinate Systems for Geodynamics

1975 ◽  
Vol 26 ◽  
pp. 395-407
Author(s):  
S. Henriksen
Keyword(s):  
Sea Level ◽  
The Other ◽  
Coordinate Systems ◽  
Mean Sea Level ◽  
The Earth ◽  
The One ◽  
Static Systems ◽  
Selection Of

The first question to be answered, in seeking coordinate systems for geodynamics, is: what is geodynamics? The answer is, of course, that geodynamics is that part of geophysics which is concerned with movements of the Earth, as opposed to geostatics which is the physics of the stationary Earth. But as far as we know, there is no stationary Earth – epur sic monere. So geodynamics is actually coextensive with geophysics, and coordinate systems suitable for the one should be suitable for the other. At the present time, there are not many coordinate systems, if any, that can be identified with a static Earth. Certainly the only coordinate of aeronomic (atmospheric) interest is the height, and this is usually either as geodynamic height or as pressure. In oceanology, the most important coordinate is depth, and this, like heights in the atmosphere, is expressed as metric depth from mean sea level, as geodynamic depth, or as pressure. Only for the earth do we find “static” systems in use, ana even here there is real question as to whether the systems are dynamic or static. So it would seem that our answer to the question, of what kind, of coordinate systems are we seeking, must be that we are looking for the same systems as are used in geophysics, and these systems are dynamic in nature already – that is, their definition involvestime.

CBED study of low-temperature InP grown by gas source MBE

1993 ◽  
Vol 51 ◽  
pp. 810-811
Author(s):  
R. Rajesh ◽  
M.J. Kim ◽  
J.S. Bow ◽  
R.W. Carpenter ◽  
G.N. Maracas
Keyword(s):  
Low Temperature ◽  
Second Phase ◽  
Material System ◽  
Ion Milling ◽  
Electrical Measurements ◽  
Gas Source ◽  
Structural And Electrical Properties ◽  
The One ◽  
Lt Inp ◽  
Gas Source Mbe

In our previous work on MBE grown low temperature (LT) InP, attempts had been made to understand the relationships between the structural and electrical properties of this material system. Electrical measurements had established an enhancement of the resistivity of the phosphorus-rich LT InP layers with annealing under a P2 flux, which was directly correlated with the presence of second-phase particles. Further investigations, however, have revealed the presence of two fundamentally different types of precipitates. The first type are the surface particles, essentially an artefact of argon ion milling and containing mostly pure indium. The second type and the one more important to the study are the dense precipitates in the bulk of the annealed layers. These are phosphorus-rich and are believed to contribute to the improvement in the resistivity of the material.The observation of metallic indium islands solely in the annealed LT layers warranted further study in order to better understand the exact reasons for their formation.

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