Characterization of high-precision resistive voltage divider and buffer amplifier for ac voltage metrology

A high-precision voltage buffer and a 10:1 resistive voltage divider have been constructed for use in ac voltage and electrical power metrology. Long-term stability of the buffer's dc response has been demonstrated by two dc sweeps performed 20 days apart, with best-fit linearized gain varying less than 1 μV/V. The absolute ac gain has been measured using a high-precision digital multimeter for 10 Hz and 1 kHz with results consistent with dc within 5 μV/V. This value agrees with the characterization of ac–dc difference using thermal converters from different producers with a variety of resistance for various voltages from 1 V to 5 V. The ac–dc difference was further characterized better than 40 μV/V for the same voltages up to 100 kHz and better than 100 μV/V for 3 V at 1 MHz. Absolute ac gain and ac–dc difference has also been measured for the voltage divider and buffer combination from 10 V to 50 V, with similar agreement up to 1 kHz. The ac–dc difference from 10 Hz to 100 kHz of this combination shows an agreement well within 30 μV/V in this entire voltage span with a total response not exceeding 125 μV/V. This make the voltage divider and buffer combination suitable for sampling electrical powers for a wide range of voltages.

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Enhanced stability of conductive polyacetylene in ladder-like surface-grafted brushes

Polymer Chemistry ◽

10.1039/c6py00977h ◽

2016 ◽

Vol 7 (36) ◽

pp. 5664-5670 ◽

Cited By ~ 7

Author(s):

Michał Szuwarzyński ◽

Karol Wolski ◽

Szczepan Zapotoczny

Keyword(s):

Term Stability ◽

Long Term Stability ◽

Enhanced Stability

Formation and characterization of polyacetylene-based brushes that exhibit exceptional long term stability in air is presented here.

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One-step preparation of Cr2O3-based ink with long-term dispersion stability for inkjet applications

Nanoscale Advances ◽

10.1039/d1na00244a ◽

2021 ◽

Author(s):

Dongjin Xie ◽

Qiuyi Luo ◽

Shen Zhou ◽

Mei Zu ◽

Haifeng Cheng

Keyword(s):

High Precision ◽

Inkjet Printing ◽

Printed Electronics ◽

Direct Writing ◽

Deposition Technique ◽

Functional Material ◽

Wide Range ◽

One Step ◽

Oled Display

Inkjet printing of functional material has shown a wide range of application in advertzing, OLED display, printed electronics and other specialized utilities that require high-precision, mask-free, direct-writing deposition technique. Nevertheless,...

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Creep Behavior of Passive Bovine Extraocular Muscle

Journal of Biomedicine and Biotechnology ◽

10.1155/2011/526705 ◽

2011 ◽

Vol 2011 ◽

pp. 1-6 ◽

Cited By ~ 3

Author(s):

Lawrence Yoo ◽

Hansang Kim ◽

Andrew Shin ◽

Vijay Gupta ◽

Joseph L. Demer

Keyword(s):

Relaxation Function ◽

Loading Rate ◽

Creep Function ◽

Testing Conditions ◽

Loading Rates ◽

Creep Coefficient ◽

Wide Range ◽

The Mean

This paper characterized bovine extraocular muscles (EOMs) using creep, which represents long-term stretching induced by a constant force. After preliminary optimization of testing conditions, 20 fresh EOM samples were subjected to four different loading rates of 1.67, 3.33, 8.33, and 16.67%/s, after which creep was observed for 1,500 s. A published quasilinear viscoelastic (QLV) relaxation function was transformed to a creep function that was compared with data. Repeatable creep was observed for each loading rate and was similar among all six anatomical EOMs. The mean creep coefficient after 1,500 seconds for a wide range of initial loading rates was at1.37±0.03(standard deviation, SD). The creep function derived from the relaxation-based QLV model agreed with observed creep to within 2.7% following 16.67%/s ramp loading. Measured creep agrees closely with a derived QLV model of EOM relaxation, validating a previous QLV model for characterization of EOM biomechanics.

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The physicochemical and biological characterization of a 24-month-stored nanocomplex based on gold nanoparticles conjugated with cetuximab demonstrated long-term stability, EGFR affinity and cancer cell death due to apoptosis

Materials Science and Engineering C ◽

10.1016/j.msec.2019.110203 ◽

2020 ◽

Vol 107 ◽

pp. 110203 ◽

Cited By ~ 3

Author(s):

Lidia M. Andrade ◽

Estefânia M.N. Martins ◽

Alice F. Versiani ◽

Daniela S. Reis ◽

Flavio G. da Fonseca ◽

...

Keyword(s):

Gold Nanoparticles ◽

Cell Death ◽

Cancer Cell ◽

Biological Characterization ◽

Term Stability ◽

Long Term Stability ◽

Cancer Cell Death

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Irradiance Observations from the UARS/SUSIM and ATLAS/SUSIM Experiments

International Astronomical Union Colloquium ◽

10.1017/s0252921100024568 ◽

1994 ◽

Vol 143 ◽

pp. 72-72 ◽

Cited By ~ 1

Author(s):

Guenter Brueckner ◽

Linton E. Floyd ◽

Paul A. Lund ◽

Dianne K. Prinz ◽

Michael E. Vanhoosier

Keyword(s):

Solar Spectrum ◽

Daily Basis ◽

Spectral Irradiance ◽

Reference Channel ◽

Term Stability ◽

Long Term Stability ◽

Solar Uv ◽

Solar Ultraviolet ◽

Better Than

The SUSIM (Solar Ultraviolet Spectral Irradiance Monitor) on board the UARS (Upper Atmosphere Research Satellite) has measured the solar UV output from 120 nm to 400 nm on a daily basis since October 1991. A reference channel records a solar spectrum semi-annually only to reduce the instrument degradation of this channel and to provide long-term stability marks. Four deuterium lamps are used at monthly, semi-annual and annual intervals to provide long term calibration of the instrument. A preliminary analysis of the long term stability of SUSIM-UARS indicates that the precision of the instrument should be better than a few percent. The repeatability of two scans is better than 0.2%. A simplified SUSIM instrument is flying on NASA’s ATLAS Spacelab missions anually to provide calibration points for the SUSIM-UARS.

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Multiplicity of Galactic Cepheids from long-baseline interferometry

Astronomy and Astrophysics ◽

10.1051/0004-6361/201834614 ◽

2019 ◽

Vol 622 ◽

pp. A164 ◽

Cited By ~ 7

Author(s):

A. Gallenne ◽

P. Kervella ◽

S. Borgniet ◽

A. Mérand ◽

G. Pietrzyński ◽

...

Keyword(s):

High Precision ◽

Radial Velocities ◽

Single Line ◽

Radial Pulsation ◽

Mass Measurements ◽

Long Baseline ◽

Car T ◽

Term Objective ◽

Better Than

Aims. We aim at detecting and characterizing the main-sequence companions of a sample of known and suspected Galactic binary Cepheids. The long-term objective is to accurately and independently measure the Cepheid masses and distances. Methods. We used the multi-telescope interferometric combiners CHARA/MIRC and VLTI/PIONIER to detect and measure the astrometric positions of the high-contrast companions orbiting 16 bright Galactic Cepheids. We made use of the CANDID algorithm to search for the companions and set detection limits from interferometric observations. We also present new high-precision radial velocity measurements which were used to fit radial pulsation and orbital velocities. Results. We report the detection of the companions orbiting the Cepheids U Aql, BP Cir, and S Mus, possible detections for FF Aql, Y Car, BG Cru, X Sgr, V350 Sgr, and V636 Sco, while no component is detected around U Car, YZ Car, T Mon, R Mus, S Nor, W Sgr, and AH Vel. For U Aql and S Mus, we performed a preliminary orbital fit combining their astrometric measurements with newly obtained high-precision single-line radial velocities, providing the full set of orbital elements and pulsation parameters. Assuming the distance from a period-luminosity (P-L) relation for both Cepheids, we estimated preliminary masses of MU Aql = 4.97 ± 0.62 M⊙ and MS Mus = 4.63 ± 0.99 M⊙. For YZ Car, W Sgr, V350 Sgr, and V636 Sco, we revised the spectroscopic orbits using new high-precision radial velocities, while we updated the pulsation parameters for BP Cir, BG Cru, S Nor, and AH Vel. Our interferometric observations also provide measurements of the angular diameters, which can be used in a Baade-Wesselink type analysis. Conclusions. We now have several astrometric detections of Cepheid companions. When radial velocities of the companions are available, such systems will provide accurate and independent masses and distances. Orbital parallaxes with an accuracy better than 5% will be particularly useful for a better calibration of the P-L relation. The final Gaia parallaxes will also be particularly helpful for single-line spectroscopic systems, where mass and distance are degenerate. Mass measurements are necessary for a better understanding of the age and evolution of Cepheids.

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Biochemical Characterization of Phenylacetaldehyde Dehydrogenases from Styrene-degrading Soil Bacteria

Applied Biochemistry and Biotechnology ◽

10.1007/s12010-020-03421-8 ◽

2020 ◽

Author(s):

Juliane Zimmerling ◽

Michel Oelschlägel ◽

Carolin Großmann ◽

Matthias Voitel ◽

Michael Schlömann ◽

...

Keyword(s):

Esterase Activity ◽

Soil Bacteria ◽

Biochemical Characterization ◽

Specific Activity ◽

Aldehyde Dehydrogenases ◽

Long Term Stability ◽

Almost All ◽

Different Characteristics

Abstract Four phenylacetaldehyde dehydrogenases (designated as FeaB or StyD) originating from styrene-degrading soil bacteria were biochemically investigated. In this study, we focused on the Michaelis-Menten kinetics towards the presumed native substrate phenylacetaldehyde and the obviously preferred co-substrate NAD+. Furthermore, the substrate specificity on four substituted phenylacetaldehydes and the co-substrate preference were studied. Moreover, these enzymes were characterized with respect to their temperature as well as long-term stability. Since aldehyde dehydrogenases are known to show often dehydrogenase as well as esterase activity, we tested this capacity, too. Almost all results showed clearly different characteristics between the FeaB and StyD enzymes. Furthermore, FeaB from Sphingopyxis fribergensis Kp5.2 turned out to be the most active enzyme with an apparent specific activity of 17.8 ± 2.1 U mg-1. Compared with that, both StyDs showed only activities less than 0.2 U mg-1 except the overwhelming esterase activity of StyD-CWB2 (1.4 ± 0.1 U mg-1). The clustering of both FeaB and StyD enzymes with respect to their characteristics could also be mirrored in the phylogenetic analysis of twelve dehydrogenases originating from different soil bacteria.

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NO2 and NH3 Sensing Characteristics of Inkjet Printing Graphene Gas Sensors

Sensors ◽

10.3390/s19153379 ◽

2019 ◽

Vol 19 (15) ◽

pp. 3379 ◽

Cited By ~ 3

Author(s):

Caterina Travan ◽

Alexander Bergmann

Keyword(s):

Gas Sensors ◽

Inkjet Printing ◽

High Mobility ◽

High Sensitivity ◽

Low Noise ◽

Manufacturing Method ◽

Long Term Stability ◽

Wide Range ◽

Ideal Technique

Graphene is a good candidate for filling the market requirements for cheap, high sensitivity, robust towards contamination, low noise, and low power consumption gas sensors, thanks to its unique properties, i.e., large surface, high mobility, and long-term stability. Inkjet printing is a cheap additive manufacturing method allowing fast, relatively precise and contactless deposition of a wide range of materials; it can be considered therefore the ideal technique for fast deposition of graphene films on thin substrates. In this paper, the sensitivity of graphene-based chemiresistor gas sensors, fabricated through inkjet printing, is investigated using different concentrations of graphene in the inks. Samples have been produced and characterized in terms of response towards humidity, nitrogen dioxide, and ammonia. The presented results highlight the importance of tuning the layer thickness and achieving good film homogeneity in order to maximize the sensitivity of the sensor.

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