scholarly journals A remarkable property of cycloidal curves

2021 ◽  
Vol 12 (33) ◽  
pp. 9-19
Author(s):  
Mikhail Vladimirovich Taldykin
Keyword(s):  
Theoretical Work ◽  
Trigonometric Function ◽  
Plane Curves ◽  
Mechanical Method ◽  
Remarkable Property ◽  
Theoretical Terms ◽  
Graphical Construction ◽  
Line Passing ◽  
Angle Of Deviation ◽  
Angle Of Rotation

The purpose of this theoretical work is to establish a connection between the most important properties of plane curves: cycloids and sinusoids. For this, a drawing mechanism is considered, which simultaneously draws a sinusoid and two cycloids. Based on the results obtained using this mechanical method of obtaining curves, the following important, previously unknown, theoretical facts are established. Firstly, new in theoretical terms is that the sinusoid is not represented as a graph of a trigonometric function, but as a locus of points equidistant from the current points of two cycloids: an ordinary and another cycloid congruent to the original one, inverted and shifted along the axis by half a period. Secondly, the line passing through the current points of these cycloids is nothing like a normal to the resulting sinusoid. This property greatly simplifies the graphical construction of such a normal. And, finally, a simple trigonometric relationship was established between the angle of rotation of the generating circle and the angle of deviation of the normal from the vertical.

The O–C diagrams of minor planets − a new approach to modelling the rotation

1999 ◽  
Vol 173 ◽  
pp. 185-188
Author(s):  
Gy. Szabó ◽  
K. Sárneczky ◽  
L.L. Kiss
Keyword(s):  
Error Analysis ◽  
Time Dependence ◽  
Theoretical Work ◽  
Minor Planet ◽  
Minor Planets ◽  
New Approach ◽  
Preliminary Results ◽  
Ccd Observations

AbstractA widely used tool in studying quasi-monoperiodic processes is the O–C diagram. This paper deals with the application of this diagram in minor planet studies. The main difference between our approach and the classical O–C diagram is that we transform the epoch (=time) dependence into the geocentric longitude domain. We outline a rotation modelling using this modified O–C and illustrate the abilities with detailed error analysis. The primary assumption, that the monotonity and the shape of this diagram is (almost) independent of the geometry of the asteroids is discussed and tested. The monotonity enables an unambiguous distinction between the prograde and retrograde rotation, thus the four-fold (or in some cases the two-fold) ambiguities can be avoided. This turned out to be the main advantage of the O–C examination. As an extension to the theoretical work, we present some preliminary results on 1727 Mette based on new CCD observations.

Peculiarity Parameters

1976 ◽  
Vol 32 ◽  
pp. 233-254
Author(s):  
H. M. Maitzen
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Theoretical Work ◽  
Observational Evidence ◽  
Rotator Model ◽  
Peculiar Behaviour ◽  
Field Spectrum ◽  
Oblique Rotator ◽  
Ap Stars ◽  
The Way

Ap stars are peculiar in many aspects. During this century astronomers have been trying to collect data about these and have found a confusing variety of peculiar behaviour even from star to star that Struve stated in 1942 that at least we know that these phenomena are not supernatural. A real push to start deeper theoretical work on Ap stars was given by an additional observational evidence, namely the discovery of magnetic fields on these stars by Babcock (1947). This originated the concept that magnetic fields are the cause for spectroscopic and photometric peculiarities. Great leaps for the astronomical mankind were the Oblique Rotator model by Stibbs (1950) and Deutsch (1954), which by the way provided mathematical tools for the later handling pulsar geometries, anti the discovery of phase coincidence of the extrema of magnetic field, spectrum and photometric variations (e.g. Jarzebowski, 1960).

Electron holography of interfaces in electroceramics

1993 ◽  
Vol 51 ◽  
pp. 1088-1089
Author(s):  
Vinayak P. Dravid ◽  
V. Ravikumar ◽  
Richard Plass
Keyword(s):  
Space Charge ◽  
Direct Evidence ◽  
Materials Science ◽  
Theoretical Work ◽  
Electron Holography ◽  
Resolution Limit ◽  
Interference Phenomenon ◽  
X Ray ◽  
Electron Sources ◽  
Science Community

With the advent of coherent electron sources with cold field emission guns (cFEGs), it has become possible to utilize the coherent interference phenomenon and perform “practical” electron holography. Historically, holography was envisioned to extent the resolution limit by compensating coherent aberrations. Indeed such work has been done with reasonable success in a few laboratories around the world. However, it is the ability of electron holography to map electrical and magnetic fields which has caught considerable attention of materials science community.There has been considerable theoretical work on formation of space charge on surfaces and internal interfaces. In particular, formation and nature of space charge have important implications for the performance of numerous electroceramics which derive their useful properties from electrically active grain boundaries. Bonnell and coworkers, in their elegant STM experiments provided the direct evidence for GB space charge and its sign, while Chiang et al. used the indirect but powerful technique of x-ray microchemical profiling across GBs to infer the nature of space charge.

Social Cognition in Gilles de la Tourette Syndrome

2019 ◽  
Vol 30 (4) ◽  
pp. 243-249
Author(s):  
Ronja Weiblen ◽  
Melanie Jonas ◽  
Sören Krach ◽  
Ulrike M. Krämer
Keyword(s):  
Tourette Syndrome ◽  
Social Cognitive ◽  
Mirror Neuron System ◽  
Mirror Neuron ◽  
Theoretical Work ◽  
Neural Processes ◽  
The Social ◽  
Decision Making System ◽  
Social Decision Making ◽  
Work Done

Abstract. Research on the neural mechanisms underlying Gilles de la Tourette syndrome (GTS) has mostly concentrated on abnormalities in basal ganglia circuits. Recent alternative accounts, however, focused more on social and affective aspects. Individuals with GTS show peculiarities in their social and affective domain, including echophenomena, coprolalia, and nonobscene socially inappropriate behavior. This article reviews the experimental and theoretical work done on the social symptoms of GTS. We discuss the role of different social cognitive and affective functions and associated brain networks, namely, the social-decision-making system, theory-of-mind functions, and the so-called “mirror-neuron” system. Although GTS affects social interactions in many ways, and although the syndrome includes aberrant social behavior, the underlying cognitive, affective, and neural processes remain to be investigated.

The use of Information Technology as Tools of Developing Educational Communications for Realizing the Personal Potential of University Students

2020 ◽  
pp. 81-92
Author(s):  
Andrey Ivanovich Shutenko ◽  
◽  
Elena Nikolaevn Shutenko ◽  
Julia Petrovna Derevyanko ◽  
◽  
...  
Keyword(s):  
Communication Technologies ◽  
Developmental Model ◽  
Learning Activity ◽  
Information Communication Technologies ◽  
Information Communication ◽  
Theoretical Terms ◽  
Higher Education System ◽  
Leading Role ◽  
Informational Environment

The article is devoted to the problem of educational communications development as a sphere of implementation of modern information-communication technologies in the higher education system. The purpose of the article is to present the structure and functions of educational communications aimed at the development of personal potential and self-realization of students. Methodology. The study is based on the methodology of personal and communicative-informational approaches in education, psychological-pedagogical provisions on the structure of communication, the leading role of learning activity, didactic principles of building an educational-informational environment. In theoretical terms, the study is based on the idea of the indirect implementation of ICT in education through the development of educational communications. The developing structure of educational communications, including didactic, informational-gnostic, interactive, psychological, attractive-motivational, value-semantic components, is presented. The possibilities of developing personal potential in educational communications are considered. The author’s developmental model of ICT functions is presented, which includes clusters of actual and latent functions aimed at the formation of information-educational space for the development of students’ personal potential. In conclusion, a inference was made about the prospects of the indirect introduction of modern ICT as tools for the development and functioning of various educational communications. At the same time, it is essential that these communications perform psychological and pedagogical tasks and functions.

War in Social Thought

2012 ◽  
Author(s):  
Hans Joas ◽  
Wolfgang Knöbl
Keyword(s):  
Twentieth Century ◽  
Intellectual History ◽  
Large Scale ◽  
Theoretical Work ◽  
German Idealism ◽  
Social Thought ◽  
Social Progress ◽  
Modern World ◽  
Critical History ◽  
Original Argument

This book provides a sweeping critical history of social theories about war and peace from Thomas Hobbes to the present. It presents both a broad intellectual history and an original argument as it traces the development of thinking about war over more than 350 years—from the premodern era to the period of German idealism and the Scottish and French enlightenments, and then from the birth of sociology in the nineteenth century through the twentieth century. While focusing on social thought, the book draws on many disciplines, including philosophy, anthropology, and political science. It demonstrate the profound difficulties most social thinkers—including liberals, socialists, and those intellectuals who could be regarded as the first sociologists—had in coming to terms with the phenomenon of war, the most obvious form of large-scale social violence. With only a few exceptions, these thinkers, who believed deeply in social progress, were unable to account for war because they regarded it as marginal or archaic, and on the verge of disappearing. This overly optimistic picture of the modern world persisted in social theory even in the twentieth century, as most sociologists and social theorists either ignored war and violence in their theoretical work or tried to explain it away. The failure of the social sciences and especially sociology to understand war, the book argues, must be seen as one of the greatest weaknesses of disciplines that claim to give a convincing diagnosis of our times.

Symmetry Breaking and the Turn-On Fluorescence of Small, Highly Strained Carbon Nanohoops

2019 ◽  
Author(s):  
Terri Lovell ◽  
Curtis Colwell ◽  
Lev N. Zakharov ◽  
Ramesh Jasti
Keyword(s):  
Symmetry Breaking ◽  
Theoretical Work ◽  
P Systems ◽  
Quantum Yields ◽  
Size Dependent ◽  
New Class ◽  
Carbon Carbon Bond ◽  
Conjugated Macrocycles ◽  
Structural Manipulation ◽  
Highly Strained

<p>[<i>n</i>]Cycloparaphenylenes, or “carbon nanohoops,” are unique conjugated macrocycles with radially oriented p-systems similar to those in carbon nanotubes. The centrosymmetric nature and conformational rigidity of these molecules lead to unusual size-dependent photophysical characteristics. To investigate these effects further and expand the family of possible structures, a new class of related carbon nanohoops with broken symmetry is disclosed. In these structures, referred to as <i>meta</i>[<i>n</i>]cycloparaphenylenes, a single carbon-carbon bond is shifted by one position in order to break the centrosymmetric nature of the parent [<i>n</i>]cycloparaphenylenes. Advantageously, the symmetry breaking leads to bright emission in the smaller nanohoops, which are typically non-fluorescent due to optical selection rules. Moreover, this simple structural manipulation retains one of the most unique features of the nanohoop structures-size dependent emissive properties with relatively large extinction coefficents and quantum yields. Inspired by earlier theoretical work by Tretiak and co-workers, this joint synthetic, photophysical, and theoretical study provides further design principles to manipulate the optical properties of this growing class of molecules with radially oriented p-systems.</p>

Symmetry Breaking and the Turn-On Fluorescence of Small, Highly Strained Carbon Nanohoops

2019 ◽  
Author(s):  
Terri Lovell ◽  
Curtis Colwell ◽  
Lev N. Zakharov ◽  
Ramesh Jasti
Keyword(s):  
Symmetry Breaking ◽  
Theoretical Work ◽  
P Systems ◽  
Quantum Yields ◽  
Size Dependent ◽  
New Class ◽  
Carbon Carbon Bond ◽  
Conjugated Macrocycles ◽  
Structural Manipulation ◽  
Highly Strained

<p>[<i>n</i>]Cycloparaphenylenes, or “carbon nanohoops,” are unique conjugated macrocycles with radially oriented p-systems similar to those in carbon nanotubes. The centrosymmetric nature and conformational rigidity of these molecules lead to unusual size-dependent photophysical characteristics. To investigate these effects further and expand the family of possible structures, a new class of related carbon nanohoops with broken symmetry is disclosed. In these structures, referred to as <i>meta</i>[<i>n</i>]cycloparaphenylenes, a single carbon-carbon bond is shifted by one position in order to break the centrosymmetric nature of the parent [<i>n</i>]cycloparaphenylenes. Advantageously, the symmetry breaking leads to bright emission in the smaller nanohoops, which are typically non-fluorescent due to optical selection rules. Moreover, this simple structural manipulation retains one of the most unique features of the nanohoop structures-size dependent emissive properties with relatively large extinction coefficents and quantum yields. Inspired by earlier theoretical work by Tretiak and co-workers, this joint synthetic, photophysical, and theoretical study provides further design principles to manipulate the optical properties of this growing class of molecules with radially oriented p-systems.</p>

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