scholarly journals Astrometric Mass Ratios of 248 Long-period Binary Stars Resolved in Hipparcos and Gaia EDR3

2021 ◽  
Vol 162 (6) ◽  
pp. 260
Author(s):  
Valeri V. Makarov ◽  
Claus Fabricius
Keyword(s):  
Binary Stars ◽  
Binary Systems ◽  
Signal To Noise Ratio ◽  
High Signal ◽  
Proper Motions ◽  
Signal To Noise ◽  
Long Period ◽  
Mass Ratios ◽  
The Mean ◽  
The Absolute

Abstract Using the absolute astrometric positions and proper motions for common stars in the Hipparcos and Gaia catalogs separated by 24.75 yr in the mean epoch, we compute mass ratios for long-period, resolved binary systems without any astrophysical assumptions or dependencies, except the presence of inner binary subsystems that may perturb the observed mean proper motions. The mean epoch positions of binary companions from the Hipparcos Double and Multiple System Annex are used as the first epoch. The mean positions and proper motions of carefully cross-matched counterparts in Gaia EDR3 comprise the second epoch data. Selecting only results with sufficiently high signal-to-noise ratio and discarding numerous optical pairs, we construct a catalog of 248 binary systems, which is published online. Several cases with unusual properties or results are also discussed.

A compact guided-wave EMAT with pulsed electromagnet for ferromagnetic tube inspection

2020 ◽  
Vol 64 (1-4) ◽  
pp. 951-958
Author(s):  
Tianhao Liu ◽  
Yu Jin ◽  
Cuixiang Pei ◽  
Jie Han ◽  
Zhenmao Chen
Keyword(s):  
Power Plants ◽  
Signal To Noise Ratio ◽  
Small Diameter ◽  
Performance Testing ◽  
Guided Wave ◽  
High Signal ◽  
Receiver Coil ◽  
Signal To Noise ◽  
Corrosion Defects

Small-diameter tubes that are widely used in petroleum industries and power plants experience corrosion during long-term services. In this paper, a compact inserted guided-wave EMAT with a pulsed electromagnet is proposed for small-diameter tube inspection. The proposed transducer is noncontact, compact with high signal-to-noise ratio and unattractive to ferromagnetic tubes. The proposed EMAT is designed with coils-only configuration, which consists of a pulsed electromagnet and a meander pulser/receiver coil. Both the numerical simulation and experimental results validate its feasibility on generating and receiving L(0,2) mode guided wave. The parameters for driving the proposed EMAT are optimized by performance testing. Finally, feasibility on quantification evaluation for corrosion defects was verified by experiments.

Narrow-frequency sharp-angular filters using all-dielectric cascaded meta-gratings

Nanophotonics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 3443-3450 ◽  
Author(s):  
Wei-Nan Liu ◽  
Rui Chen ◽  
Wei-Yi Shi ◽  
Ke-Bo Zeng ◽  
Fu-Li Zhao ◽  
...  
Keyword(s):  
Thin Film ◽  
Signal To Noise Ratio ◽  
Incident Angle ◽  
Design Strategy ◽  
Transmission Peak ◽  
High Signal ◽  
Waveguide Array ◽  
Signal To Noise ◽  
Center Wavelength ◽  
Noise Ratio

AbstractSelective transmission or filtering always responds to either frequency or incident angle, so as hardly to maximize signal-to-noise ratio in communication, detection and sensing. Here, we propose compact meta-filters of narrow-frequency sharp-angular transmission peak along with broad omnidirectional reflection sidebands, in all-dielectric cascaded subwavelength meta-gratings. The inherent collective resonance of waveguide-array modes and thin film approximation of meta-grating are employed as the design strategy. A unity transmission peak, locating at the incident angle of 44.4° and the center wavelength of 1550 nm, is demonstrated in a silicon meta-filter consisting of two-layer silicon rectangular meta-grating. These findings provide possibilities in cascaded meta-gratings spectroscopic design and alternative utilities for high signal-to-noise ratio applications in focus-free spatial filtering and anti-noise systems in telecommunications.

Does Motion Perception Follow Weber's Law?

Perception ◽  
1995 ◽  
Vol 24 (4) ◽  
pp. 363-372 ◽  
Author(s):  
Johannes M Zanker
Keyword(s):  
Motion Perception ◽  
Stimulus Intensity ◽  
Signal To Noise Ratio ◽  
Weber’S Law ◽  
Noise Levels ◽  
Signal To Noise ◽  
Weber's Law ◽  
The Absolute ◽  
Noise Ratio ◽  
Random Dot Patterns

The subjective strength of a percept often depends on the stimulus intensity in a nonlinear way. Such coding is often reflected by the observation that the just-noticeable difference between two stimulus intensities (JND) is proportional to the absolute stimulus intensity. This behaviour, which is usually referred to as Weber's Law, can be interpreted as a compressive nonlinearity extending the operating range of a sensory system. When the noise superimposed on a motion stimulus is increased along a logarithmic scale (in order to provide linear steps in subjective difference) in motion-coherency measurements, observers often report that the subjective differences between the various noise levels increase together with the absolute level. This observation could indicate a deviation from Weber's Law for variation of motion strength as obtained by changing the signal-to-noise ratio in random-dot kinematograms. Thus JNDs were measured for the superposition of uncorrelated random-dot patterns on static random-dot patterns and three types of motion stimuli realised as random-dot kinematograms, namely large-field and object ‘Fourier’ motion (all or a group of dots move coherently), ‘drift-balanced’ motion (a travelling region of static dots), and paradoxical ‘theta’ motion (the dots on the surface of an object move in opposite direction to the object itself). For all classes of stimuli, the JNDs when expressed as differences in signal-to-noise ratio turned out to increase with the signal-to-noise ratio, whereas the JNDs given as percentage of superimposed noise appear to be similar for all tested noise levels. Thus motion perception is in accordance with Weber's Law when the signal-to-noise ratio is regarded as stimulus intensity, which in turn appears to be coded in a nonlinear fashion. In general the Weber fractions are very large, indicating a poor differential sensitivity in signal-to-noise measurements.

scholarly journals Low-dose, phase-contrast mammography with high signal-to-noise ratio

2016 ◽  
Vol 7 (2) ◽  
pp. 381 ◽  
Author(s):  
Lukas B. Gromann ◽  
Dirk Bequé ◽  
Kai Scherer ◽  
Konstantin Willer ◽  
Lorenz Birnbacher ◽  
...  
Keyword(s):  
Phase Contrast ◽  
Low Dose ◽  
Signal To Noise Ratio ◽  
High Signal ◽  
Signal To Noise ◽  
Noise Ratio

Broadband dual-comb coherent anti-Stokes Raman spectroscopy at high signal-to-noise ratio

CLEO: 2015 ◽  
2015 ◽  
Author(s):  
Ming Yan ◽  
Simon Holzner ◽  
Theodor W. Hänsch ◽  
Nathalie Picqué
Keyword(s):  
Raman Spectroscopy ◽  
Signal To Noise Ratio ◽  
High Signal ◽  
Signal To Noise ◽  
Noise Ratio ◽  
Anti Stokes

Research on LIFT Technology for 3D Seismic Denoising in Coalfield

2014 ◽  
Vol 556-562 ◽  
pp. 6328-6331
Author(s):  
Su Zhen Shi ◽  
Yi Chen Zhao ◽  
Li Biao Yang ◽  
Yao Tang ◽  
Juan Li
Keyword(s):  
Signal To Noise Ratio ◽  
High Signal ◽  
3D Seismic ◽  
Signal To Noise ◽  
Denoising Method ◽  
Seismic Processing ◽  
Work Area ◽  
Noise Data ◽  
Noise Ratio ◽  
Effective Signal

The LIFT technology has applied in process of denoising to ensure the imaging precision of minor faults and structure in 3D coalfield seismic processing. The paper focused on the denoising process in two study areas where the LIFT technology is used. The separation of signal and noise is done firstly. Then denoising would be done in the noise data. The Data of weak effective signal that is from the noise data could be blended with the original effective signal to reconstruct the denoising data, so the result which has high signal-to-noise ratio and preserved amplitude is acquired. Thus the fact shows that LIFT is an effective denoising method for 3D seismic in coalfield and could be used widely in other work area.

Head Instability Detection for Testing Process in Perpendicular Magnetic Recording System

2013 ◽  
Vol 770 ◽  
pp. 319-322 ◽  
Author(s):  
Piya Kovintavewat ◽  
Santi Koonkarnkhai ◽  
Aimamorn Suvichakorn
Keyword(s):  
Magnetic Recording ◽  
Signal To Noise Ratio ◽  
Disk Drive ◽  
Detection Algorithm ◽  
Recording System ◽  
High Signal ◽  
Signal To Noise ◽  
Perpendicular Magnetic Recording ◽  
Read Head ◽  
Pass Through

During hard disk drive (HDD) testing process, the magneto-resistive read (MR) head is analyzed and checked if the head is defective or not. Baseline popping (BLP) is one of the crucial problems caused by head instability, whose effect can distort the readback signal to the extent of causing possible sector read failure. Without BLP detection algorithm, the defective read head might pass through HDD assembling process, thus producing an unreliable HDD. This situation must be prevented so as to retain customer satisfaction. This paper proposes a simple (but efficient) BLP detection algorithm for perpendicular magnetic recording systems. Results show that the proposed algorithm outperforms the conventional one in terms of both the percentage of detection and the percentage of false alarm, when operating at high signal-to-noise ratio.

High signal-to-noise ratio quantum well bolometer materials

2006 ◽  
Author(s):  
Stanley Wissmar ◽  
Linda Höglund ◽  
Jan Andersson ◽  
Christian Vieider ◽  
Susan Savage ◽  
...  
Keyword(s):  
Quantum Well ◽  
Signal To Noise Ratio ◽  
High Signal ◽  
Signal To Noise ◽  
Noise Ratio

Bias in estimates of mb at small magnitudes

1976 ◽  
Vol 66 (6) ◽  
pp. 1887-1904
Author(s):  
J. F. Evernden ◽  
W. M. Kohler
Keyword(s):  
Signal To Noise Ratio ◽  
High Signal ◽  
Systematic Bias ◽  
Station Correction ◽  
Signal To Noise ◽  
Identification Criterion ◽  
The Difference ◽  
Operational Networks ◽  
Worldwide Network ◽  
Simple Parameter

abstract A possibly significant factor in application of an identification criterion such as MS:mb is systematic bias in mb magnitude estimates at small magnitudes due to a variety of factors. Magnitude bias is the difference in magnitude value, positive or negative, between an observed network-based magnitude value and the expected magnitude value if all stations of the network had detected the event at high signal-to-noise ratio. This paper constitutes a partial study of the general problem; it evaluates the bias effects expected from both conceptual and operational networks when using parameters for noise and signal levels and standard deviations derived from observations, and when correcting observed station mb values solely via a simple parameter station correction factor. The analysis shows that any bias effects on mb inherent in any operational or potential worldwide network are so small as to have negligible effect on use of an MS:mb discriminant.

Gravity meter observation of free modes excited by the August 19, 1977 Indonesia earthquake

1979 ◽  
Vol 69 (5) ◽  
pp. 1445-1454
Author(s):  
John A. Linton ◽  
D. E. Smylie ◽  
O. G. Jensen
Keyword(s):  
Signal To Noise Ratio ◽  
Quartz Fiber ◽  
Large Signal ◽  
Signal To Noise ◽  
Definitive Evidence ◽  
Long Period ◽  
Noise Ratio

abstract Free modes with signal-to-noise ratio in the range of 40 to 55 dB were observed in the record taken by a vertical broadband quartz fiber gravimeter system opeating in Montreal following the event of August 19, 1977 in Indonesia. The large signal-to-noise ratio has permitted very stable Q estimates to be made for a number of the fundamental spheroidal modes. The very long-period band shows no definitive evidence of signal other than the expected tidal lines.

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