An extremal system with a preferential direction of search

1970 ◽  
Vol 13 (11) ◽  
pp. 1259-1263 ◽  
Author(s):  
N. N. Leonov
Keyword(s):  
Extremal System ◽  
Preferential Direction

scholarly journals Observing the onset of outflow collimation in a massive protostar

Science ◽  
2015 ◽  
Vol 348 (6230) ◽  
pp. 114-117 ◽  
Author(s):  
C. Carrasco-González ◽  
J. M. Torrelles ◽  
J. Cantó ◽  
S. Curiel ◽  
G. Surcis ◽  
...  
Keyword(s):  
Water Vapor ◽  
Star Formation ◽  
Accretion Disks ◽  
Density Stratification ◽  
Radio Continuum ◽  
Preferential Direction ◽  
Compact Source ◽  
Current Paradigm

The current paradigm of star formation through accretion disks, and magnetohydrodynamically driven gas ejections, predicts the development of collimated outflows, rather than expansion without any preferential direction. We present radio continuum observations of the massive protostar W75N(B)-VLA 2, showing that it is a thermal, collimated ionized wind and that it has evolved in 18 years from a compact source into an elongated one. This is consistent with the evolution of the associated expanding water-vapor maser shell, which changed from a nearly circular morphology, tracing an almost isotropic outflow, to an elliptical one outlining collimated motions. We model this behavior in terms of an episodic, short-lived, originally isotropic ionized wind whose morphology evolves as it moves within a toroidal density stratification.

Near IR and visual polarimetry of the Planetary Nebula M2-9

2018 ◽  
Vol 14 (S343) ◽  
pp. 480-482
Author(s):  
Silvana G. Navarro ◽  
Omar Serrano ◽  
Abraham Luna ◽  
Rangaswami Devaraj ◽  
Luis J. Corral ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Accretion Disk ◽  
Linear Polarization ◽  
Planetary Nebula ◽  
Planetary Nebulae ◽  
Circumstellar Disk ◽  
Preferential Direction ◽  
Visual Region ◽  
Near Ir ◽  
San Pedro

AbstractBipolar and more complex morphologies observed in planetary nebulae have been explained by two principal hypotheses: by the existence of a companion producing a circumstellar disk, by the effects of a magnetic field, or by a combination of both. The polarimetric analysis of these objects could give information about the presence of dust grains aligned with any preferential direction, due to a magnetic field or to the action of radiative torques (RAT). We performed polarimetric observations of some planetary nebulae in order to detect linear polarization and (in the best scenario) to detect the signature of an accretion disk in these objects. We observed in the visual region with POLIMA at the San Pedro Mártir observatory, and with POLICAN the NIR polarimeter in the Guillermo Haro observatory. We present the result of these observations in one of these objects: the PN M2-9.

scholarly journals Subwavelength Silicon Nanoblocks for Directional Emission Manipulation

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1242
Author(s):  
Tianyue Zhang ◽  
Xuewei Li ◽  
Jian Xu ◽  
Xiaoming Zhang ◽  
Zi-Lan Deng ◽  
...  
Keyword(s):  
Light Emission ◽  
Coupled System ◽  
Low Loss ◽  
Preferential Direction ◽  
Nanophotonic Devices ◽  
Directional Emission ◽  
Direct Light ◽  
Highly Sensitive ◽  
Field Radiation ◽  
Magnetic Resonances

Manipulating the light emission direction and boosting its directivity have essential importance in integrated nanophotonic devices. Here, we theoretically propose a single dielectric silicon nanoblock as an efficient, multifunctional and ultracompact all-dielectric nanoantenna to direct light into a preferential direction. Unidirectional scattering of a plane wave as well as switchable directive emission fed by a localized emitter are demonstrated within the nanoantenna. The high directionalities are revealed to originate from a variety of mechanisms that can coexist within a single nanoblock, which contribute to the far-field radiation patterns of the outcoming light, thanks to the wealth of multipolar electric and magnetic resonances. The efficient beam redirections are also observed, which are sensitive to the local configurations of the emitter antenna coupled system. The designed antenna, with extreme geometry simplicity, ultracompact and low-loss features, could be favorable for highly sensitive sensing as well as applications in optical nanocircuits.

Directional Coarsening of γ′ Phase Induced by Phase Transformation Stress

2005 ◽  
Vol 20 (9) ◽  
pp. 2314-2321 ◽  
Author(s):  
K. Zhao ◽  
Y.H. Ma ◽  
L.H. Lou ◽  
Z.Q. Hu
Keyword(s):  
Free Energy ◽  
Phase Transformation ◽  
Uniform Distribution ◽  
Strain Energy ◽  
Coherency Strain ◽  
Preferential Direction ◽  
Nickel Based Superalloy ◽  
Directional Coarsening ◽  
Energy Theory ◽  
Transformation Stress

It was found that directional coarsening was induced by phase transformation stress due to non-uniform distribution of μ phase in an experimental nickel-based superalloy. The mechanism based on the existing diffusion and coherency strain energy theory has been discussed. It was concluded that directional coarsening was the course of dissolving of γ′ portion with high free energy, diffusing and growing on the existed γ′ particles along a preferential direction.

Social Media and E-Commerce

2020 ◽  
pp. 121-149
Author(s):  
Tiago Da Costa ◽  
Beatriz Casais
Keyword(s):  
Social Media ◽  
Focus Group ◽  
Preferential Direction ◽  
Intrinsic Rewards ◽  
Self Interest ◽  
Fertile Ground ◽  
One To One ◽  
Selection Of

Several studies have approached the link between social media and e-commerce with different lenses, however, the study of motivations for sharing content specifically from e-commerce websites into social media has not been thoroughly approached and provides fertile ground for further exploration. This chapter uncovers which motivations serve as a background for individuals sharing intentions of e-commerce content. After a focus group with 7 individuals, results indicate participants focus more on intrinsic rewards than extrinsic ones when sharing, that self-interest is more predominant than reciprocity as a motivator for sharing, one-to-one exchanges are the preferential direction of exchange. Also, websites with cleaner designs and higher usability positively impact sharing intentions, experiences tend to be more likely shared than physical products, and participants are purposeful in their selection of sharing channels.

On the recorded motion of the S phase at Florissant*

1952 ◽  
Vol 42 (2) ◽  
pp. 145-154
Author(s):  
Ross R. Heinrich ◽  
Harry K. Haill
Keyword(s):  
S Phase ◽  
Central American ◽  
Aleutian Islands ◽  
Aleutian Island ◽  
South American ◽  
Wave Analysis ◽  
S Wave ◽  
Preferential Direction ◽  
Saint Louis ◽  
S Waves

Abstract The initial motions of the P and S phases have been tabulated from the original seismograms of sixty earthquakes which recorded at the Florissant station in the years 1927–1938. The epicenters of these earthquakes were within limited areas of the following regions: the Aleutian Islands, the west-central coast of South America, and Central America. The study indicates that the Florissant seismograms show a preferential direction of motion for both P and S waves in the recordings of certain earthquakes from selected regions. The data compiled on the S phase indicated that a majority of the Aleutian and South American earthquakes recorded a sharp impulsive initial northeast motion at Florissant. The Central American earthquakes studied recorded S phases of somewhat indefinite onset which did not exhibit a preferential motion as they were read. The results of the application of Neumann's method of S-wave analysis to the Saint Louis seismograms of two selected Aleutian Island earthquakes are presented and a brief discussion of some possible structural implications of the various data is given.

On the operating modes of a step-by-step extremal system

1969 ◽  
Vol 12 (7) ◽  
pp. 803-807
Author(s):  
N. N. Leonov
Keyword(s):  
Extremal System ◽  
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