A broadband VLBI system using transportable stations for geodesy and metrology: an alternative approach to the VGOS concept

AbstractWe have developed a broadband VLBI (very long baseline interferometry) system inspired by the concept of the VLBI Global Observing System (VGOS). The new broadband VLBI system was implemented in the Kashima 34 m antenna and in two transportable stations utilizing 2.4 m diameter antennas. The transportable stations have been developed as a tool for intercontinental frequency comparison but are equally useful for geodesy. To enable practical use of such small VLBI stations in intercontinental VLBI, we have developed the procedure of node-hub style VLBI: In joint observation with a large, high sensitivity ‘hub’ antenna, the closure delay relation provides a virtual delay observable between ‘node’ stations. This overcomes the limited sensitivity of the small diameter node antennas, while error sources associated with large diameter antennas, such as gravitational deformation and delay changes in necessarily long signal cables, are eliminated. We show that this scheme does not result in an increased sensitivity to radio source structure if one side of the baseline triangle is kept short. We have performed VLBI experiments utilizing this approach over both short range and intercontinental distance. This article describes the system components, signal processing procedure, experiment, and results in terms of baseline repeatability. Our measurements reveal signatures of structure effects in the correlation amplitude of several of the observed radio sources. We present a model of the frequency-dependent source size for 1928+738 derived from correlation amplitude data observed in four frequency bands.

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The First VERA Astrometry Catalog

Publications of the Astronomical Society of Japan ◽

10.1093/pasj/psaa018 ◽

2020 ◽

Vol 72 (4) ◽

Cited By ~ 6

Author(s):

Tomoya Hirota ◽

◽

Takumi Nagayama ◽

Mareki Honma ◽

Yuuki Adachi ◽

...

Keyword(s):

Spiral Structure ◽

Galactic Center ◽

Rapid Variation ◽

Error Sources ◽

Long Baseline ◽

Circular Rotation ◽

Motion Measurements ◽

Very Long Baseline Array ◽

Source Structure ◽

Maser Sources

Abstract We present the first astrometry catalog from the Japanese VLBI (very long baseline interferometer) project VERA (VLBI Exploration of Radio Astrometry). We have compiled all the astrometry results from VERA, providing accurate trigonometric-annual-parallax and proper-motion measurements. In total, 99 maser sources are listed in the VERA catalog. Among them, 21 maser sources are newly reported, while the rest of the 78 sources are referred to in previously published results or those in preparation for forthcoming papers. The accuracy in the VERA astrometry is revisited and compared with that from the other VLBI astrometry projects such as BeSSeL (The Bar and Spiral Structure Legacy) Survey and GOBELINS (the Gould’s Belt Distances Survey) with the VLBA (Very Long Baseline Array). We have confirmed that most of the astrometry results are consistent with each other, and the largest error sources are due to source structure of the maser features and their rapid variation, along with the systematic calibration errors and different analysis methods. Combined with the BeSSeL results, we estimate the up-to-date fundamental Galactic parameters of $R_{0}=7.92\pm 0.16_{\rm {stat.}}\pm 0.3_{\rm {sys.}}\:$kpc and $\Omega _{\odot }=30.17\pm 0.27_{\rm {stat.}}\pm 0.3_{\rm {sys.}}\:$km$\:$s$^{-1}\:$kpc$^{-1}$, where $R_{0}$ and $\Omega _{\odot }$ are the distance from the Sun to the Galactic center and the Sun’s angular velocity of the Galactic circular rotation, respectively.

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Differences in the brain stem terminations of large- and small-diameter vestibular primary afferents

Journal of Neurophysiology ◽

10.1152/jn.1995.74.3.1362 ◽

1995 ◽

Vol 74 (3) ◽

pp. 1362-1366 ◽

Cited By ~ 9

Author(s):

J. A. Huwe ◽

E. H. Peterson

Keyword(s):

Brain Stem ◽

Large Diameter ◽

Small Diameter ◽

Movement Control ◽

Three Dimensions ◽

Significant Shift ◽

Axon Diameter ◽

Vestibular Complex ◽

The Brain ◽

Adjacent Brain

1. We visualized the central axons of 32 vestibular afferents from the posterior canal by extracellular application of horseradish peroxidase, reconstructed them in three dimensions, and quantified their morphology. Here we compare the descending limbs of central axons that differ in parent axon diameter. 2. The brain stem distribution of descending limb terminals (collaterals and associated varicosities) varies systematically with parent axon diameter. Large-diameter afferents concentrate their terminals in rostral regions of the medial/descending nuclei. As axon diameter decreases, there is a significant shift of terminal concentration toward the caudal vestibular complex and adjacent brain stem. 3. Rostral and caudal regions of the medial/descending nuclei have different labyrinthine, cerebellar, intrinsic, commissural, and spinal connections; they are believed to play different roles in head movement control. Our data help clarify the functions of large- and small-diameter afferents by showing that they contribute differentially to rostral and caudal vestibular complex.

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Tin Disulfide-Coated Microfiber for Humidity Sensing with Fast Response and High Sensitivity

Crystals ◽

10.3390/cryst11060648 ◽

2021 ◽

Vol 11 (6) ◽

pp. 648

Author(s):

Aijie Liang ◽

Jingyuan Ming ◽

Wenguo Zhu ◽

Heyuan Guan ◽

Xinyang Han ◽

...

Keyword(s):

Humidity Sensor ◽

Small Diameter ◽

High Sensitivity ◽

Large Change ◽

Small Variation ◽

Response Speed ◽

Fast Response ◽

Tin Disulfide ◽

Recovery Times ◽

Response And Recovery

Breath monitoring is significant in assessing human body conditions, such as cardiac and pulmonary symptoms. Optical fiber-based sensors have attracted much attention since they are immune to electromagnetic radiation, thus are safe for patients. Here, a microfiber (MF) humidity sensor is fabricated by coating tin disulfide (SnS2) nanosheets onto the surface of MF. The small diameter (~8 μm) and the long length (~5 mm) of the MF promise strong interaction between guiding light and SnS2. Thus, a small variation in the relative humidity (RH) will lead to a large change in optical transmitted power. A high RH sensitivity of 0.57 dB/%RH is therefore achieved. The response and recovery times are estimated to be 0.08 and 0.28 s, respectively. The high sensitivity and fast response speed enable our SnS2-MF sensor to monitor human breath in real time.

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Remote, Long-Pathlength Cell for High-Sensitivity Raman Spectroscopy

Applied Spectroscopy ◽

10.1366/0003702874868089 ◽

1987 ◽

Vol 41 (1) ◽

pp. 126-130 ◽

Cited By ~ 60

Author(s):

Scott D. Schwab ◽

Richard L. McCreery

Keyword(s):

Fiber Optics ◽

Laser Light ◽

Capillary Tube ◽

High Sensitivity ◽

Sample Tube ◽

Increased Sensitivity ◽

Sampling Systems ◽

Power Densities ◽

Objective Being ◽

Focused Beam

Fiber optics were used to interface a Raman spectrometer to a long (1 m) sample tube, with the objective being increased sensitivity. Internal reflection of the laser light and the Raman scatter within the sample tube permitted a long solution length to be sampled, increasing the Raman sensitivity by factors of 30–50 over conventional capillary tube sampling systems. In addition, the sample was subjected to much lower power densities than with systems employing a focused beam, thus minimizing radiation damage. Detection limits of 10−9 to 10−8 M were achieved for resonance Raman scatterers, and normal Raman scatterers could be detected at the 1 × 10−5 M level.

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Elastic Modulus and Elasticity Ratio of Malignant Breast Lesions with Shear Wave Ultrasound Elastography: Variations with Different Region of Interest and Lesion Size

Diagnostics ◽

10.3390/diagnostics11061015 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1015

Author(s):

Antonio Bulum ◽

Gordana Ivanac ◽

Eugen Divjak ◽

Iva Biondić Špoljar ◽

Martina Džoić Dominković ◽

...

Keyword(s):

Elastic Modulus ◽

Shear Wave ◽

Large Diameter ◽

Small Diameter ◽

Shear Wave Elastography ◽

Lesion Size ◽

Ultrasound Elastography ◽

Breast Lesions ◽

Malignant Breast ◽

The Impact

Shear wave elastography (SWE) is a type of ultrasound elastography with which the elastic properties of breast tissues can be quantitatively assessed. The purpose of this study was to determine the impact of different regions of interest (ROI) and lesion size on the performance of SWE in differentiating malignant breast lesions. The study included 150 female patients with histopathologically confirmed malignant breast lesions. Minimal (Emin), mean (Emean), maximal (Emax) elastic modulus and elasticity ratio (e-ratio) values were measured using a circular ROI size of 2, 4 and 6 mm diameters and the lesions were divided into large (diameter ≥ 15 mm) and small (diameter < 15 mm). Highest Emin, Emean and e-ratio values and lowest variability were observed when using the 2 mm ROI. Emax values did not differ between different ROI sizes. Larger lesions had significantly higher Emean and Emax values, but there was no difference in e-ratio values between lesions of different sizes. In conclusion, when measuring the Emin, Emean and e-ratio of malignant breast lesions using SWE the smallest possible ROI size should be used regardless of lesion size. ROI size has no impact on Emax values while lesion size has no impact on e-ratio values.

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Event Horizon Telescope observations of the jet launching and collimation in Centaurus A

Nature Astronomy ◽

10.1038/s41550-021-01417-w ◽

2021 ◽

Author(s):

Michael Janssen ◽

Heino Falcke ◽

Matthias Kadler ◽

Eduardo Ros ◽

Maciek Wielgus ◽

...

Keyword(s):

Black Holes ◽

Event Horizon ◽

Galactic Nuclei ◽

Galactic Centre ◽

Radio Jets ◽

Long Baseline ◽

Wide Range ◽

Terahertz Frequencies ◽

Source Structure ◽

Centaurus A

AbstractVery-long-baseline interferometry (VLBI) observations of active galactic nuclei at millimetre wavelengths have the power to reveal the launching and initial collimation region of extragalactic radio jets, down to 10–100 gravitational radii (rg ≡ GM/c2) scales in nearby sources1. Centaurus A is the closest radio-loud source to Earth2. It bridges the gap in mass and accretion rate between the supermassive black holes (SMBHs) in Messier 87 and our Galactic Centre. A large southern declination of −43° has, however, prevented VLBI imaging of Centaurus A below a wavelength of 1 cm thus far. Here we show the millimetre VLBI image of the source, which we obtained with the Event Horizon Telescope at 228 GHz. Compared with previous observations3, we image the jet of Centaurus A at a tenfold higher frequency and sixteen times sharper resolution and thereby probe sub-lightday structures. We reveal a highly collimated, asymmetrically edge-brightened jet as well as the fainter counterjet. We find that the source structure of Centaurus A resembles the jet in Messier 87 on ~500 rg scales remarkably well. Furthermore, we identify the location of Centaurus A’s SMBH with respect to its resolved jet core at a wavelength of 1.3 mm and conclude that the source’s event horizon shadow4 should be visible at terahertz frequencies. This location further supports the universal scale invariance of black holes over a wide range of masses5,6.

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Analysis Influence of Pile Embedded Depth and Diameter on Pile Tip Resistance

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.353-356.459 ◽

2013 ◽

Vol 353-356 ◽

pp. 459-462

Author(s):

Ying Jie Zheng ◽

Bin Fang ◽

Lian Xiang Li

Keyword(s):

Large Diameter ◽

Small Diameter ◽

Stiffness Ratio ◽

Initial Stiffness ◽

Tip Resistance

Pile tip absolute settlement curves and relative settlement curves of several working cases were analyzed. It is found that load-settlement curve characteristic related to the selection standard. The tip resistance initial stiffness of each case was analyzed. Results show that the small diameter pile has higher initial stiffness than large diameter pile, embedded depth has little influence on initial stiffness ratio, but increment of initial stiffness is linear with embedded depth growth.

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New method of poultry selection

Genetika i razvedenie zhivotnyh ◽

10.31043/2410-2733-2021-1-61-66 ◽

2021 ◽

pp. 61-66

Author(s):

E. Rehleckaya ◽

A. Dymkov ◽

L. Lazarets ◽

A. Maltsev

Keyword(s):

Egg Production ◽

Initial Period ◽

Large Diameter ◽

Small Diameter ◽

Live Weight ◽

Individual Variability ◽

Egg Laying ◽

New Method ◽

Egg Diameter ◽

Correlation Rate

Purpose: Install the influence of the «small diameter of the egg» on the living mass and the reproductive qualities of chickens of meat crosses and the quail of meat breeds.Materials and methods. The selection was carried out along egg production and mass of eggs and additionally on the average small diameter of 5 eggs by value of ≥0.5σ from the average for the herd, while the evaluation on the basis of the «small diameter of the egg» was carried out in chickens aged 238 days of life, quails — 70 days of life. Calculated the average for each female and the average for the herd. For further reproduction, chickens carrying eggs with a small egg diameter ≥0.5σ from the average for the herd. Studies were held in SibNIP on quail and on the courses.Results. In the initial period of the egg laying, the individual variability of the small diameter of the egg — more than 10% (in the future, the figure decreased). The close correlation rate of the small egg diameter in the first half of the egg laying with such at the end of the bird's operation period was revealed. It has been established that the large diameter of the egg has a positive reliable connection with a lively mass, but negative with egg production. The reliable correlation rate of the small diameter of the egg with a live weight at a 42-day age, as well as with the derivation of eggs. The inheritance coefficients of the small diameter of the egg are comparable to the inheritance coefficients of the mass of eggs and significantly exceed those for a large diameter of the egg. The selection according to the small diameter of the eggs by ≥0.5σ from the average for the herd led to the fact that the chickens of the experimental groups reliably exceeded the live weight in the SB level of 1.57%, in the line G8 — by 1.35%. The superiority of a lively mass of quail of experienced groups was more pronounced than that of the chickens: the Pharaoh breed — by 4.15%, the Texas white breed is 4.22%. In relation to the derivation of eggs, a similar trend was traced. The derivation of eggs in quails of experienced groups was more than 4.59–4.98%; Country, respectively, 4.57–5.22%. Egg production of females of comparable groups of both chickens and quail was almost on the same level, and the difference was unreliable.Conclusion. It was established that a new method of breeding the poultry of the meat direction of productivity allows without decreasing egg production to increase the living mass of chickens of meat crosses by 1.5%, rewinds of meat breeds — by 4%, the derivation of eggs, respectively, by 4–5%. The method is intended for early prediction of females productivity during breeding selection.

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VLBA+GBT observations of the COSMOS field and radio source counts at 1.4 GHz

Astronomy and Astrophysics ◽

10.1051/0004-6361/201832969 ◽

2018 ◽

Vol 616 ◽

pp. A128 ◽

Cited By ~ 1

Author(s):

N. Herrera Ruiz ◽

E. Middelberg ◽

A. Deller ◽

V. Smolčić ◽

R. P. Norris ◽

...

Keyword(s):

Radio Source ◽

Flux Density ◽

Lower Limit ◽

High Sensitivity ◽

Host Galaxy ◽

Radio Sources ◽

Source Population ◽

Star Forming ◽

Brightness Temperatures ◽

Long Baseline

We present very long baseline interferometry (VLBI) observations of 179 radio sources in the COSMOS field with extremely high sensitivity using the Green Bank Telescope (GBT) together with the Very Long Baseline Array (VLBA) (VLBA+GBT) at 1.4 GHz, to explore the faint radio population in the flux density regime of tens of μJy. Here, the identification of active galactic nuclei (AGN) is based on the VLBI detection of the source, meaning that it is independent of X-ray or infrared properties. The milli-arcsecond resolution provided by the VLBI technique implies that the detected sources must be compact and have large brightness temperatures, and therefore they are most likely AGN (when the host galaxy is located at z ≥ 0.1). On the other hand, this technique only allows us to positively identify when a radio-active AGN is present, in other words, we cannot affirm that there is no AGN when the source is not detected. For this reason, the number of identified AGN using VLBI should be always treated as a lower limit. We present a catalogue containing the 35 radio sources detected with the VLBA+GBT, ten of which were not previously detected using only the VLBA. We have constructed the radio source counts at 1.4 GHz using the samples of the VLBA and VLBA+GBT detected sources of the COSMOS field to determine a lower limit for the AGN contribution to the faint radio source population. We found an AGN contribution of >40−75% at flux density levels between 150 μJy and 1 mJy. This flux density range is characterised by the upturn of the Euclidean-normalised radio source counts, which implies a contribution of a new population. This result supports the idea that the sub-mJy radio population is composed of a significant fraction of radio-emitting AGN, rather than solely by star-forming galaxies, in agreement with previous studies.

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Copolymer-Nanoparticles Mixture in a Cylindrical Pore

NANO ◽

10.1142/s179329201750045x ◽

2017 ◽

Vol 12 (04) ◽

pp. 1750045

Author(s):

Jun-Xing Pan ◽

Yu-Qi Guo ◽

Yu-Fang Han ◽

Min-Na Sun ◽

Jin-Jun Zhang

Keyword(s):

Phase Transition ◽

Electrical Conductivity ◽

Polymer Nanocomposites ◽

Diblock Copolymer ◽

Large Diameter ◽

Small Diameter ◽

Confinement Effect ◽

Cylindrical Pore ◽

Disorder Phase Transition ◽

Novel Structures

Computer simulation is carried out for investigating the effect of nanoparticles on diblock copolymer morphology under cylindrical confinement. The phase diagrams of polymer nanocomposites with nanoparticle-block wetting strength and concentration of nanoparticles are obtained in different nanopores. In small diameter nanopore, there is almost no influence of nanoparticles on the diblock copolymer morphology because of the stronger confinement effect; in middle diameter nanopore, the system can self-assemble into various novel structures due to the interaction between confinement effect and nanoparticles effect; in large diameter nanopore, due to the stronger effect of nanoparticles, a disorder-order-disorder phase transition occurs with the wetting strength and concentration of nanoparticles increasing. This result can be useful in designing new nanocomposites with advanced electrical conductivity and/or mechanical strength.

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