Averaging of spectral power and phase via vector diagram best fits without reference electrode or reference channel

1986 ◽  
Vol 64 (4) ◽  
pp. 350-363 ◽  
Author(s):  
D Lehmann ◽  
H Ozaki ◽  
I Pal
Keyword(s):  
Spectral Power ◽  
Reference Electrode ◽  
Vector Diagram ◽  
Reference Channel

scholarly journals Two-Channel Graphene pH Sensor Using Semi-Ionic Fluorinated Graphene Reference Electrode

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4184
Author(s):  
Dae Hoon Kim ◽  
Woo Hwan Park ◽  
Hong Gi Oh ◽  
Dong Cheol Jeon ◽  
Joon Mook Lim ◽  
...  
Keyword(s):  
Electrolyte Solution ◽  
Field Effect ◽  
Field Effect Transistor ◽  
Ph Value ◽  
Characteristic Curve ◽  
Reference Electrode ◽  
Reference Channel ◽  
Buffer Solution ◽  
Positive Direction ◽  
Effect Transistor

A reference electrode is necessary for the working of ion-sensitive field-effect transistor (ISFET)-type sensors in electrolyte solutions. The Ag/AgCl electrode is normally used as a reference electrode. However, the Ag/AgCl reference electrode limits the advantages of the ISFET sensor. In this work, we fabricated a two-channel graphene solution gate field-effect transistor (G-SGFET) to detect pH without an Ag/AgCl reference electrode in the electrolyte solution. One channel is the sensing channel for detecting the pH and the other channel is the reference channel that serves as the reference electrode. The sensing channel was oxygenated, and the reference channel was fluorinated partially. Both the channels were directly exposed to the electrolyte solution without sensing membranes or passivation layers. The transfer characteristics of the two-channel G-SGFET showed ambipolar field-effect transistor (FET) behavior (p-channel and n-channel), which is a typical characteristic curve for the graphene ISFET, and the value of VDirac was shifted by 18.2 mV/pH in the positive direction over the range of pH values from 4 to 10. The leakage current of the reference channel was 16.48 nA. We detected the real-time pH value for the two-channel G-SGFET, which operated stably for 60 min in the buffer solution.

scholarly journals PECULIARITIES OF NEUROCOGNITIVE PROCESSES IN PUPILS OF SECONDARY SCHOOL IN MERITOCRATIC EDUCATION

2020 ◽  
Vol 20 (4) ◽  
pp. 146-151
Author(s):  
I. V. Redka ◽  
G. M. Danilenko ◽  
Zh. V. Sotnikova-Malashkina ◽  
O. Ya. Mykhalchul
Keyword(s):  
Secondary School ◽  
Cognitive Load ◽  
Mental Arithmetic ◽  
Spectral Power ◽  
International System ◽  
Reference Electrode ◽  
Educational Process ◽  
General Tendency ◽  
Frequency Bands ◽  
Frontoparietal Network

Psychological and physiological features of gifted schoolchildren in the context of the general tendency towards learning intensification and excessive use of technical means of learning determine their extreme sensitivity to the factors of the educational environment. The introduction of a meritocratic education system requires checking the compliance between the educational process organization and the psychological and physiological schoolchildren capabilities. This article describes the study on the comparison of neurocognitive processes of the secondary school pupils (10-11 years) in meritocratic (n = 60) and traditional (n = 26) educational systems based on the comparison of the relative spectral power of the electroencephalogram (EEG) frequency bands at rest state and cognitive load (mental arithmetic with subtraction). EEG potentials were led monopolarly from 21 locus according to the international system "10-20" using the average reference electrode. Artefact-free EEG datasets of 35–45 s length were registered and analyzed. The common characteristics of EEG patterns taken from the schoolchildren at meritocratic education include a significantly higher proportion of alpha activity in the frontal cortex and beta-2 activity throughout the convex cerebral surface at rest and cognitive load. Mental arithmetic caused changes in all EEG frequency bands, mainly in the frontoparietal network in the condition under meritocratic education, while under traditional education the changes were mainly registered in the delta band in the temporal and parietal cerebral cortex. We have found out that schoolchildren in the meritocratic system are characterized by a higher level of cerebral functional maturity and demonstrate more mature activation patterns of cortical structures during the mental arithmetic testing. This indicates the beneficial developmental impact of meritocratic education.

Associations Between Self-Report of Emotional State and the EEG Patterns in Affective Disorders Patients

2010 ◽  
Vol 24 (1) ◽  
pp. 33-40 ◽  
Author(s):  
Miroslaw Wyczesany ◽  
Jan Kaiser ◽  
Anton M. L. Coenen
Keyword(s):  
State Energy ◽  
Emotional State ◽  
Spectral Power ◽  
Bipolar Affective Disorder ◽  
Affective State ◽  
Manic Episode ◽  
High Energy ◽  
Self Report ◽  
Major Depressive ◽  
High Tension

The study determines the associations between self-report of ongoing emotional state and EEG patterns. A group of 31 hospitalized patients were enrolled with three types of diagnosis: major depressive disorder, manic episode of bipolar affective disorder, and nonaffective patients. The Thayer ADACL checklist, which yields two subjective dimensions, was used for the assessment of affective state: Energy Tiredness (ET) and Tension Calmness (TC). Quantitative analysis of EEG was based on EEG spectral power and laterality coefficient (LC). Only the ET scale showed relationships with the laterality coefficient. The high-energy group showed right shift of activity in frontocentral and posterior areas visible in alpha and beta range, respectively. No effect of ET estimation on prefrontal asymmetry was observed. For the TC scale, an estimation of high tension was related to right prefrontal dominance and right posterior activation in beta1 band. Also, decrease of alpha2 power together with increase of beta2 power was observed over the entire scalp.

Variations Across the Menstrual Cycle in EEG Activity During Thinking and Mental Relaxation

1999 ◽  
Vol 13 (3) ◽  
pp. 163-172 ◽  
Author(s):  
R. Krug ◽  
M. Mölle ◽  
H.L. Fehm ◽  
J. Born
Keyword(s):  
Menstrual Cycle ◽  
Divergent Thinking ◽  
Spectral Power ◽  
Plasma Concentrations ◽  
Task Demands ◽  
Menstrual Phase ◽  
Convergent Thinking ◽  
Eeg Activity ◽  
Dimensional Complexity ◽  
Mental Relaxation

Abstract Previous studies have indicated: (1) peak performance on tests of divergent creative thinking during the ovulatory phase of the menstrual cycle; (2) compared to convergent analytical thinking, divergent thinking was found to be associated with a distinctly increased dimensional complexity of ongoing EEG activity. Based on these findings, we hypothesized that cortical information processing during the ovulatory phase is characterized by an increased EEG dimensionality. Each of 16 women was tested on 3 occasions: during the ovulatory phase, the luteal phase, and menses. Presence of the phases was confirmed by determination of plasma concentrations of estradiol, progesterone, and luteinizing hormone. The EEG was recorded while the women performed: (1) tasks of divergent thinking; (2) tasks of convergent thinking; and (3) during mental relaxation. In addition to EEG dimensional complexity, conventional spectral power analysis was performed. Behavioral data confirmed enhanced creative performance during the ovulatory phase while convergent thinking did not vary across cycle phases. EEG complexity was higher during divergent than convergent thought, but this difference remained unaffected by the menstrual phase. Influences of the menstrual phase on EEG activity were most obvious during mental relaxation. In this condition, women during the ovulatory phase displayed highest EEG dimensionality as compared with the other cycle phases, with this effect being most prominent over the central and parietal cortex. Concurrently, power within the alpha frequency band as well as theta power at frontal and parietal leads were lower during the luteal than ovulatory phase. EEG results indicate that task demands of thinking overrode effects of menstrual cycle. However, with a less demanding situation, an ovulatory increase in EEG dimensionality became prominent suggesting a loosening of associative habits during this phase.

Supercontinuum laser-based monochromatic radiant source for detector spectral responsivity characterization in the range 0.9–1.6 μm using absolute cryogenic radiometer

2020 ◽  
pp. 28-33
Author(s):  
A. Yu. Dunaev ◽  
A. S. Baturin ◽  
V. N. Krutikov ◽  
S. P. Morozova
Keyword(s):  
Power Distribution ◽  
Spectral Power ◽  
Feedback System ◽  
Operating Mode ◽  
Spectral Responsivity ◽  
Spectral Power Distribution ◽  
Cryogenic Radiometer ◽  
Supercontinuum Laser ◽  
Radiant Power ◽  
Double Monochromator

An improved monochromatic radiant source with spectral bandwidth of 4 nm based on supercontinuum laser and a double monochromator was included in absolute cryogenic radiometer-based facility to improve the accuracy of spectral responsivity measurement in the range 0.9–1.6 μm. The developed feedback system ensures stabilization of monochromatic radiant power with standard deviation up to 0.025 %. Radiant power that proceeds detector under test or absolute cryogenic radiometer varies from 0.1 to 1.5 mW in dependence of wavelength. The spectral power distribution of its monochromatic source for various operating mode is presented.

Evaluation of a molybdenum sulfide reference electrode in hot alkaline solutions

TAPPI Journal ◽  
2010 ◽  
Vol 9 (7) ◽  
pp. 35-41
Author(s):  
OUTI A. HYÖKYVIRTA ◽  
TOM E. GUSTAFSSON
Keyword(s):  
Molybdenum Disulfide ◽  
Surface Film ◽  
Reference Electrode ◽  
Exposure Period ◽  
Molybdenum Sulfide ◽  
Alkaline Solutions ◽  
Internal Reference ◽  
Cell Potential ◽  
Pulp Digester ◽  
Alkaline Sulfide

This investigation evaluated the applicability of a molybdenum sulfide reference electrode (MSRE) as an internal reference electrode for use in alkaline sulfide solutions over a range of pulp digester liquors at 170°C. The electrode remained stable during the exposure period of two weeks. The experimentally determined half cell potential of the MSRE is E = -0.91 VSHE. The surface of the MSRE was examined by scanning electron microscope (SEM) and electron spectroscopy for chemical analysis (ESCA) to verify the chemical composition of the thin surface film. Based on ESCA studies, the surface film contained molybdenum disulfide and sodium disulfide. During storage of the specimens, sulfide was partly oxidized to sodium sulfite in air. Next to the metallic molybdenum, a mixed molybdenum disulfide and molybdenum hydroxide layer was detected.

Inflections of Periodicities of Background Photon Spectral Power Densities Are Predicted by the Lorentz Contraction for a Potential Indicator for the Intrinsic Structure of Space

2016 ◽  
pp. 4014-4017
Author(s):  
Michael A Persinger
Keyword(s):  
Spectral Power ◽  
Neutral Hydrogen ◽  
Intrinsic Structure ◽  
Lorentz Contraction ◽  
Intrinsic Nature ◽  
Basic Interval ◽  
Power Spectral ◽  
The Difference ◽  
Background Photon ◽  
Power Densities

                The value for the Lorentz contraction to produce a discrepancy for a hypothetical number that reflects a property (21.3π4) of sub-matter space was calculated. When applied to time the contraction would be ~35 min. The difference in mass-equivalent energy for an electron at c (the velocity of light in a vacuum) and the required v was ~2 ·10-20 J which has emerged as a significant quantity that may permeate from the force at Planck’s Length when applied across the wavelength of the neutral hydrogen line. Two separate types of photomultiplier instruments (digital and analogue) measuring with different sampling rates for background photon quantities over 50 randomly selected days demonstrated averaged conspicuous inflections of standardized spectral power densities around 35 min. This is the same basic interval where microvariations in the value of the gravitational constant (G) approached a limit at which white noise dominated.  The possibility is considered that this value for temporal inflections in photon power spectral densities may reflect the intrinsic nature of space-time contractions that relate gravity and photons.

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