scholarly journals Pulsar NP 0532: Recent Results on Strong Pulses Obtained at Arecibo

1971 ◽  
Vol 46 ◽  
pp. 103-109
Author(s):  
Carl Heiles ◽  
John M. Rankin
Keyword(s):  
Circular Polarization ◽  
Frequency Spectrum ◽  
Linear Polarization ◽  
The Other ◽  
Average Intensity ◽  
Detailed Structure ◽  
Continuous Frequency

New observations have been made of strong pulses from NP 0532. Linear polarization is typically 25 per cent and circular polarization is less than 10 per cent but definitely not zero. A comparison of pulse shapes at 429.9 and 430.1 MHz showed significant differences in detailed structure and polarization. In another study strong pulses at 318 and 111 MHz did not occur together although a strong pulse at one frequency was accompanied by an above average intensity at the other frequency. Similar behaviour was found at 111 and 74 MHz. We conclude that strong pulses do not have a smooth continuous frequency spectrum.

scholarly journals Broadband Linear Polarization in Ap Stars

1993 ◽  
Vol 138 ◽  
pp. 305-309
Author(s):  
Marco Landolfi ◽  
Egidio Landi Degl’Innocenti ◽  
Maurizio Landi Degl’Innocenti ◽  
Jean-Louis Leroy ◽  
Stefano Bagnulo
Keyword(s):  
Magnetic Field ◽  
Circular Polarization ◽  
Linear Polarization ◽  
Rotation Axis ◽  
Spectral Lines ◽  
Line Of Sight ◽  
Long Time ◽  
Rotating Star ◽  
Ap Stars ◽  
The Magnetic Field

AbstractBroadband linear polarization in the spectra of Ap stars is believed to be due to differential saturation between σ and π Zeeman components in spectral lines. This mechanism has been known for a long time to be the main agent of a similar phenomenon observed in sunspots. Since this phenomenon has been carefully calibrated in the solar case, it can be confidently used to deduce the magnetic field of Ap stars.Given the magnetic configuration of a rotating star, it is possible to deduce the broadband polarization at any phase. Calculations performed for the oblique dipole model show that the resulting polarization diagrams are very sensitive to the values of i (the angle between the rotation axis and the line of sight) and β (the angle between the rotation and magnetic axes). The dependence on i and β is such that the four-fold ambiguity typical of the circular polarization observations ((i,β), (β,i), (π-i,π-β), (π-β,π-i)) can be removed.

An experimentalist's view of the galvanomagnetic and thermomagnetic properties of potassium

1982 ◽  
Vol 60 (5) ◽  
pp. 679-686 ◽  
Author(s):  
R. Fletcher
Keyword(s):  
Experimental Investigation ◽  
Charge Density ◽  
Charge Density Wave ◽  
High Field ◽  
Density Wave ◽  
The Other ◽  
Detailed Structure ◽  
Precise Nature ◽  
A Charge ◽  
Thermomagnetic Properties

This paper provides a brief survey of the experimental and theoretical situation regarding the galvano- and thermomagnetic properties of potassium viewed within the context of the behaviour of other metals. Most of the data are consistent with various sample imperfections as being the major source of the anomalies that are found. However, the precise nature of the imperfections and the mechanism by which the imperfections produce the anomalies are not yet known. It is argued that the recently discovered detailed structure in the high field induced torque of K should be subjected to intensive experimental investigation before drawing any conclusions with regards to the possible presence of a charge density wave; the other magnetotransport properties offer little evidence either for or against such a possibility.

scholarly journals Oh Observations in the Directions of Galactic Thermal Sources

1967 ◽  
Vol 20 (4) ◽  
pp. 407 ◽  
Author(s):  
RX McGee ◽  
FF Gardner ◽  
BJ Robinson
Keyword(s):  
Linear Polarization ◽  
The Other ◽  
Radio Sources ◽  
Line Radiation ◽  
Thermal Sources ◽  
Made In

A survey for the hydroxyl line radiation has been made in the directions of 30 radio sources (most of them thermal) with the 210 ft telescope of beamwidth 12'� 2 and the multichannel line receiver of bandwidths 10 and 37 kHz. The line at frequency 1665�401 MHz was observed for all sources and the other three lines at 1612, 1667, and 1720 MHz were observed for 10 of the more important sources. The latter were investigated for circular and linear polarization.

scholarly journals Simultaneous Five Color (UBVRI) Polarimetry of VV Puppis

1987 ◽  
Vol 93 ◽  
pp. 203-203
Author(s):  
V. Piirola ◽  
A. Reiz ◽  
G.V. Coyne
Keyword(s):  
Circular Polarization ◽  
Linear Polarization ◽  
Wavelength Dependence ◽  
Position Angle ◽  
Orbital Inclination ◽  
V Band ◽  
Highly Active ◽  
Phase Interval ◽  
In The Beginning ◽  
Bright Phase

AbstractObservations of linear and circular polarization in five colour bands during a highly active state of VV Puppis in January 86 are reported. A strong linear polarization pulse with the maximum in the blue, PB ≈ 22%, is observed at the end of the bright phase when the active pole is at the limb and a weaker secondary pulse, PB ≈ 7%, is seen in the beginning of the bright phase, when the active pole reappears. Strong positive circular polarization is also observed in the blue and the ultraviolet, РU ≈ PB ≈ 18%, PV ≈ 10% during the bright phase. The circular polarization reverses the sign in the B and V bands during the faint phase and a negative polarization hump is seen when the active pole crosses the limb. The circular polarization in the V band reaches the value PV ≈ −10% at the hump, after which it remains near PV ≈ −5% during the faint phase. This is probably due to radiation coming from the second, less active pole and accretion thus takes place onto both poles. The wavelength dependences of the positive and negative parts of the circular polarization curve are different and no polarization reversal is seen in the U band. The position angle of the linear polarization is well determined during a large portion of the cycle, especially in the V band, thanks to the activity from both poles. A best fit to the position angle curve, taking into account also the duration of the positive circular polarization phase interval ΔΦ = 0.40 (in the V band), yields the values of orbital inclination i = 78° ± 2° and the colatitude of the active magnetic pole ß = 146° ± 2°. The relatively good fit to the position angle data indicates that the simple dipole model is nearly correct in the case of VV Puppis. Some wavelength dependence is, however, seen in the position angle curves, especially in the I band where the slope Δθ/ΔΦ at the main pulse is considerably smaller than in the other bands. The shape of the position angle curves changes also in the blue and the ultraviolet around the middle of the bright phase. This is probably due to optical thickness effects as the side of the accretion column which is toward the observer changes near this phase.

Polarization Reconfigurable Dual-Band Rectangular Slot Antenna

Frequenz ◽  
2019 ◽  
Vol 73 (9-10) ◽  
pp. 339-351
Author(s):  
Rohit Kumar Saini
Keyword(s):  
Circular Polarization ◽  
Linear Polarization ◽  
Dual Band ◽  
Slot Antenna ◽  
Pin Diodes ◽  
Rectangular Slot ◽  
Left Hand ◽  
Right Hand ◽  
Lower Band ◽  
The Senses

Abstract A novel dual-band rectangular slot antenna is presented for dual-sense reconfigurable polarization. A W-shaped microstrip feedline and two rectangular parasitic patches are used to obtain dual-band circular polarization. Further, the feedline is modified so that the senses of polarization at the two bands are opposite. By introducing PIN-diodes in the feed lines, polarization can be switched among left-hand circular polarization (LHCP), right-hand circular polarization (RHCP), and linear polarization (LP). A prototype dual-band dual-sense antenna with f01 = 1.9 GHz and f02 = 3.45 GHz is fabricated in a 1.6 mm thick FR4 substrate. The measured circular polarized bandwidths are more than 7.6 % for the lower band and 5 % for the upper band.

scholarly journals A Simulation Study of GNSS-R Polarimetric Scattering from the Bare Soil Surface Based on the AIEM

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Xuerui Wu ◽  
Shuanggen Jin
Keyword(s):  
Soil Moisture ◽  
Circular Polarization ◽  
Soil Surface ◽  
Bare Soil ◽  
Satellite System ◽  
Equation Model ◽  
The Other ◽  
Scattering Coefficients ◽  
Remote Sensing Technique ◽  
Transmitted Signal

In the past two decades, global navigation satellite system-reflectometry (GNSS-R) has emerged as a new remote sensing technique for soil moisture monitoring. Some experiments showed that the antenna of V polarization is more favorable to receive the reflected signals, and the interference pattern technique (IPT) was used for soil moisture and retrieval of other geophysical parameters. Meanwhile, the lower satellite elevation angles are most impacted by the multipath. However, electromagnetic theoretical properties are not clear for GNSS-R soil moisture retrieval. In this paper, the advanced integral equation model (AIEM) is employed using the wave-synthesis technique to simulate different polarimetric scatterings in the specular directions. Results show when the incident angles are larger than 70°, scattering at RR polarization (the transmitted signal is right-hand circular polarization (RHCP), while the received one is also RHCP) is larger than that at LR polarization (the transmitted signal is RHCP, while the received one is left-hand circular polarization (LHCP)), while scattering at LR polarization is larger than that at RR polarization for the other incident angles (1°∼70°). There is an apparent dip for VV and VR scatterings due to the Brewster angle, which will result in the notch in the final receiving power, and this phenomenon can be used for soil moisture retrieval or vegetation corrections. The volumetric soil moisture (vms) effects on their scattering are also presented. The larger soil moisture will result in lower scattering at RR polarization, and this is very different from the scattering of the other polarizations. It is interesting to note that the surface correlation function only affects the amplitudes of the scattering coefficients at much less level, but it has no effects on the angular trends of RR and LR polarizations.

Design of multiband circularly/linearly polarized antenna for multiple wireless (WWAN/Bluetooth/WiMAX/WLAN/Downlink Satellite System)

2019 ◽  
Vol 11 (9) ◽  
pp. 967-974 ◽  
Author(s):  
Manish Sharma
Keyword(s):  
Wireless Communications ◽  
Circular Polarization ◽  
Radiation Pattern ◽  
Linear Polarization ◽  
Ground Plane ◽  
Wireless Systems ◽  
Satellite System ◽  
Multiband Antenna ◽  
Linearly Polarized ◽  
Downlink System

AbstractIn this article, a multiband antenna for various wireless communications is proposed for WWAN, Bluetooth, WiMAX, WLAN, and Downlink satellite system. The antenna consists of a radiating patch and a rectangular ground plane with four L-shaped stubs which are embedded as side arms to obtain a resonating band for WWAN (1.9GHz), Bluetooth (2.4 GHz), WiMAX (2.5, 3.5, and 5.5 GHz), and WLAN (5.5 GHz) wireless systems and a C-shaped stub is etched on the radiating patch to obtain a higher WLAN band (2.4, 5.2, and 5.8 GHz) and a satellite downlink system (7.5 GHz). The proposed antenna exhibits circular polarization at WWAN band and linear polarization for remaining applications. Also, the proposed antenna exhibits an omnidirectional radiation pattern.

scholarly journals Circular polarization in T Tauri stars

1987 ◽  
Vol 122 ◽  
pp. 131-132
Author(s):  
P. Bastien ◽  
R. Nadeau
Keyword(s):  
Circular Polarization ◽  
Linear Polarization ◽  
T Tauri Stars ◽  
T Tauri

We report the detection of circular polarization in three T Tauri stars with known intrinsic linear polarization. A circumstellar origin is required.

CANADIAN WILTSHIRE BACON: XII. EFFECT OF HEAT TREATMENT ON THE COLOUR AND COLOUR STABILITY OF BACON

1940 ◽  
Vol 18d (8) ◽  
pp. 289-299 ◽  
Author(s):  
C. A. Winkler ◽  
J. W. Hopkins
Keyword(s):  
Heat Treatment ◽  
Relative Humidity ◽  
Correlation Coefficients ◽  
The Other ◽  
Average Intensity ◽  
Colour Stability ◽  
Lower Intensity ◽  
Subsequent Exposure ◽  
Duration Of Heating ◽  
Nitrite Content

The colour of quadruplicate pieces of factory-cured bacon heated at temperatures of 20, 40, 50, 60, 70, and 80 °C. for 5, 10, 20, and 40 hr. was measured at the conclusion of heating, and also after subsequent exposure of the samples for 12, 20, and 96 hr. at 10 °C. and 95% relative humidity. Interacting effects of time and temperature of heating on colour at the conclusion of treatment were demonstrable. At 40 and 50°, total intensity increased with the duration of heating; at 60 and 70°, there was no definite trend, and at 80° it diminished markedly as the period of heating was prolonged. The maximum average intensity resulted from heating at 70°.The decrease in intensity after 12 hr. exposure was related to the duration, but not to the temperature, of previous heating. There was no significant change in intensity between 12 and 20 hr., but a further decrease was evident at the end of 96 hr. The decrease in green intensity was still related to the duration, rather than to the temperature, of heat treatment, but the effects of duration of heating on red and blue stability, noted at 12 and 20 hr., were now replaced by temperature effects.Partial correlation coefficients indicate that increased nitrite content of the meat at the conclusion of heating tended to be associated with a lower intensity of colour. On the other hand, both nitrite content and loss in weight (chiefly moisture) on heating were correlated with increased colour stability on exposure.

scholarly journals Occurrence of ticks (Acari: Ixodidae) on human hosts, in three municipalities in the State of Pará, Brazil

2010 ◽  
Vol 19 (3) ◽  
pp. 141-147 ◽  
Author(s):  
Nicolau Maués Serra-Freire
Keyword(s):  
Observational Study ◽  
Dominant Species ◽  
Rhipicephalus Sanguineus ◽  
The State ◽  
The Other ◽  
Agricultural Workers ◽  
Average Intensity ◽  
Human Beings ◽  
Transversal Line ◽  
First Case

Assuming the existence of tick parasitism in humans in the State of Pará, an aggregate observational study was developed along a transversal line in three cities of the State, during two years. Interviews and examinations of 2,160 townspeople and tourists were carried out, without discrimination of ethnic, sex, age, or social status, and classified for effects analyzed for four bands of age, six types of activities in the society, and two sexes. Larvae, nymphs, and adults of ticks had been identified with cases of parasitism involving six species, of the genus Amblyomma, the genus Ixodes, Rhipicephalus sanguineus, Anocentor nitens, and Ornithodorus talaje (the first case registered in Pará), infecting human beings. Adults and agricultural workers were most frequently attacked, followed by students. A. cajennense and R. sanguineus are the species most frequent in the parasitism affecting humans, and A. cajennense is the dominant species. The statistical prevalence was largest in Cachoeira do Arari, Ilha do Marajó. In Santarém the greatest average intensity of parasitism was for R. sanguineus, and in the other locations it wasfor A. cajennense. Agricultural workers faced the greatest risk from parasitism, and to place in practice elementary measures of prevention would reduce by 25% the number of cases.

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