scholarly journals Appearance of Ferromagnetic Property for Si Nanopolycrystalline Body and Vanishing of Electrical Resistances at Local High Frequencies

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Taku Saiki ◽  
Yukio Iida ◽  
Mitsuru Inada
Keyword(s):  
Negative Resistance ◽  
The Body ◽  
Dangling Bonds ◽  
Laser Ablation In Liquid ◽  
Ferromagnetic Property ◽  
High Frequencies ◽  
Ferromagnetic Metals ◽  
Si Nanoparticles ◽  
Unpaired Electrons ◽  
Defective Crystals

Reduction in the skin effect for the sintered Si nanopolycrystalline body as an electricity conductor at a high frequency due to its nanostructure was studied. Singular disappearance of electrical resistances near a local high magnetic harmonic frequency of a few MHz was observed. This phenomenon has not been observed for conventional ferromagnetic metals. The measured electrical resistances changed to almost 0 mΩ at room temperature. At the same time, negative resistance of the sintered Si nanopolycrystalline body was observed. It will be applicable to electronic transmittance lines or semiconductors. Numerical calculation was also performed on the electrical resistance with frequency dependency while considering the electric field and magnetic field in the sintered Si nanopolycrystalline body. The experimental and calculated results are compared. The calculation could explain the variation of the relative permittivity of the Si nanopolycrystalline body and the phenomenon for the theoretical disappearance of the resistivity at the MHz frequency. Reduced Si nanoparticles from SiO2 powder were synthesized by laser ablation in liquid. A Si nanopolycrystalline body made of the reduced Si nanoparticles was fabricated. It was found by measuring the magnetization property of the body of the sintered Si nanopolycrystalline body which is ferromagnetic. Dangling bonds (unpaired electrons) have long been known to occur due to defects in Si crystals. Perfect Si without defective crystals has no dangling bonds. However, Si nanoparticles have many dangling bonds. High-density dangling bonds cause the sintered Si nanopolycrystalline body to have ferromagnetism. In this study, the density of the unpaired electrons in the sintered Si nanopolycrystalline body was observed using ESR. It has been clarified that the Si nanopowder and the sintered Si nanopolycrystalline body have numerous dangling bonds. Both densities of the dangling bonds were evaluated.

Activity of crayfish abdominal-positioning interneurones during spontaneous and sensory-evoked movements

1986 ◽  
Vol 120 (1) ◽  
pp. 173-188 ◽  
Author(s):  
J. Jellies ◽  
J. L. Larimer
Keyword(s):  
Body Surface ◽  
High Frequency ◽  
Single Cells ◽  
Receptive Fields ◽  
The Body ◽  
Type I ◽  
High Frequencies ◽  
Premotor Interneurones ◽  
Sensory Evoked ◽  
Motor Programme

The premotor interneurones that produce coordinated abdominal movements in crayfish (Procambarus) when stimulated directly, are also ‘sensorimotor’. Sets of these interneurones respond in predictable ways to touching the body surface. One set of interneurones (type I) is activated to spiking by touch, while another (type II) receives only subthreshold influences. Several of these interneurones have overlapping receptive fields on the body surface. Touching areas of overlap activates groups of interneurones which discharge at low to moderate frequencies, rather than producing a high-frequency discharge of a single cell. No single positioning interneurone has been identified which is solely responsible for a “voluntary” (spontaneous) motor programme. When active, the positioning interneurones contribute to the production of the behaviour as a member of a constellation of such cells. The results show that this motor system comprises interneurones with sensory as well as motor properties. Although single cells can produce coordinated movements when stimulated at high frequencies, these positioning interneurones appear to function as ‘command elements’ within a large ‘command system’ and not as individual units.

LINEAR Bi-CMOS TRANSCONDUCTANCE FOR Gm-C FILTER APPLICATIONS

2002 ◽  
Vol 11 (03) ◽  
pp. 219-230
Author(s):  
J. LEE ◽  
K. HAYATLEH ◽  
F. J. LIDGEY ◽  
J. DREW
Keyword(s):  
Negative Resistance ◽  
Current Gain ◽  
High Frequencies ◽  
Combined Use

In this paper a novel transconductance Bi-CMOS stage is described. This stage makes combined use of a translinear current gain cell and a negative resistance cell, to generate a linear tuneable transconductor. The transconductance stage was designed specifically for an integrated Gm-C filter application, and is shown to perform well at high frequencies.

Frequency-dependent contractile response of isolated cardiac trabeculae under hypo-, normo-, and hyperthermic conditions

2006 ◽  
Vol 100 (5) ◽  
pp. 1727-1732 ◽  
Author(s):  
Nitisha Hiranandani ◽  
Kenneth D. Varian ◽  
Michelle M. Monasky ◽  
Paul M. L. Janssen
Keyword(s):  
Mechanical Response ◽  
Contractile Response ◽  
Contractile Function ◽  
External Environment ◽  
Output Regulation ◽  
The Body ◽  
Frequency Change ◽  
Adrenergic Stimulation ◽  
High Frequencies ◽  
Isolated Myocardium

The body is from time to time exposed to nonnormothermic conditions; both hypo- and hyperthermia can occur as a result of external (environment) or internal (pathogens, allergens) stressors. To preserve life under hypo- and hyperthermic conditions, adequate perfusion of vital organs is mandated. Although cardiac output regulation under hyperthermic conditions has been studied, the mechanical response of basic contractile function of the myocardium itself is incompletely understood. Accordingly, we set out to test mechanical output of isolated myocardium under hyperthermic conditions and to compare the results with the hypo- and normothermic response in the same tissue. We observed that, in absence of a frequency change, developed force decreased markedly. At a physiological normal stimulation rate of 6 Hz, developed force decreases to 67.2 ± 2.6% at 42°C compared with 37°C. In addition, twitch timing characteristics also accelerate, allowing for a faster relaxation; time from peak tension to 50% relaxation is ∼23% faster (from 31.4 ± 2.6 to 24.4 ± 1.7 ms). Although this faster relaxation in turn prevents a steep increase in diastolic tension at high frequencies, the very fast calcium kinetics now prevent a more complete activation of the myofilaments, resulting in a lower twitch-force maximum at hyperthermic conditions. Even at maximal β-adrenergic stimulation, developed force is well below levels reached at physiological temperature.

scholarly journals A review of the role of oxidative stress in the pathogenesis of eye diseases

2011 ◽  
Vol 70 (4) ◽  
Author(s):  
O. A. Oduntan ◽  
K. P. Masige
Keyword(s):  
Oxidative Stress ◽  
Free Radicals ◽  
Open Angle Glaucoma ◽  
Epidemiological Studies ◽  
Eye Diseases ◽  
The Body ◽  
Alpha Tocopherol ◽  
Age Related Macular Degeneration ◽  
Age Related ◽  
Unpaired Electrons

Free radicals, referred to as oxidants are molecules in the body with unpaired electrons, hence are unstable and ready to bond with other molecules with unpaired electrons.  They include Reactive Oxygen Species (ROS) such as superoxide anion radicals (·O¯), hydrogen peroxide (H202), and hydroxyl free radicals (·OH).  Endogenous sources of ROS include metabolic and other organic processes, while exogenous sources include ultraviolet radiation and environmental toxins such as smoke.  Antioxidants (oxidant scavengers) such as ascorbate, alpha-tocopherol and glutathione as well as various enzymatic compounds such as superoxide dismutase (SOD), catalase and glutathione reductase are also present in the body and in manyfoods or food supplements.  An imbalance between oxidants and antioxidants in favour of oxidantsis termed oxidative stress and can lead to cell or tissue damage and aging. Oxidative stress has been implicated in the pathogenesis of many serious systemic diseases such as diabetes, cancer and neurological disorders.  Also, laboratory and epidemiological studies have implicated oxidative stress in the pathogenesis of the majority of common serious eye diseases such as cataract, primary open angle glaucoma and age-related macular degeneration. In this article, we reviewed the current information on the roles of oxidative stress in the pathogenesis of various eye diseases and the probable roles of antioxidants.  Eye care practitioners will find this article useful as it provides information on the pathogenesis of common eye diseases. (S Afr Optom 2011 70(4) 182-190)

Fist to Face

2021 ◽  
pp. 353-367
Author(s):  
Lisa Coulthard
Keyword(s):  
The Body ◽  
High Frequencies ◽  
Digital Era ◽  
History Of ◽  
The Impact ◽  
Action Cinema

In his recent Sound: An Acoulogical Treatise, Michel Chion coins the term “corporeal covibrations” to describe the much discussed but imprecisely defined phenomena of sound’s corporeal impact. From low and high frequencies to intense loudness, sound has direct vibratory impact on the body, an association that aligns with the recent “sensory turn” in criticism. This chapter considers covibratory corporeal listening as crucial to the impact aesthetics of the cinematic punch in action cinema today. Tracing the sonic history of the cinematic punch, it interrogates the corporeal, haptic, and uncanny effects of this hyperreal sound object. With the cinematic punch, violence on screen is heard, never fully seen: and yet, in the digital era, the punch has taken on a meatier, louder, more complex role in audiovisual violence, a shift that transforms this sonic effect into a fleshy, material, and corporeally felt object.

scholarly journals PECULIARITIES OF OCCUPATIONAL PREVALENCE IN AIRCRAFT MANUFACTURING ENTERPRISES

2018 ◽  
Vol 97 (8) ◽  
pp. 731-736
Author(s):  
V. I. Kamenev ◽  
Olga V. Kameneva ◽  
A. V. Platunin
Keyword(s):  
Physical Factor ◽  
The Body ◽  
Physical Factors ◽  
Production Environment ◽  
High Frequencies ◽  
Labor Conditions ◽  
Manufacturing Enterprises ◽  
Treatment And Prevention ◽  
Aircraft Manufacturing ◽  
Good Conductor

At aircraft manufacturing enterprises, tens of thousands of employees work, whose labor conditions in most cases do not meet sanitary and hygienic requirements. Material and methods. The work assesses the risk factors of the production environment of aircraft assemblers using instrumental research methods, there was performed a physiological assessment of severity and exhaustion levels to determine the main areas of prevention. Results. The noise and vibration were determined as prioritized harmful impact (physical) factor for workers. Vibration is perceived by all tissues of the body, but mostly by the nervous and bone system. The bone system that serves as a good conductor and resonator of vibration. The nerve endings and, above all, the receptors of the skin of the distal parts of the hands are the most sensitive to the effects of vibration. The vestibular apparatus actively reacts to vibrational stimulation. In addition, vibrations of high frequencies can have an effect on the hearing aid that is close to the effect of noise. Discussion. The results of studies indicate a high risk of the formation of occupational pathology as a result of the complex impact of physical factors and the severity of the work process. Conclusion. Studies have shown the need to introduce rational work regimes and a system of treatment and prevention activities.

SELECTIVE HEATING BY SHORT RADIO WAVES AND ITS APPLICATION TO ELECTROTHERAPY

1931 ◽  
Vol 5 (5) ◽  
pp. 550-566 ◽  
Author(s):  
J. C. McLennan F.R.S. ◽  
A. C. Burton M.A.
Keyword(s):  
High Frequency ◽  
Wave Length ◽  
Theoretical Explanation ◽  
The Body ◽  
Radio Waves ◽  
High Frequencies ◽  
Selective Effect ◽  
Selective Heating ◽  
Determining Factors ◽  
Frequency Oscillator

In the first part of the paper the theoretical basis of the formulas, given in a previous communication, for the generation of heat in a poorly conducting dielectric which is placed in the field of a high-frequency oscillator, is examined in some detail. Its application to the complicated case met with in medical "radiothermy" is made and it is shown that the analysis applies with satisfactory accuracy to this case, though not to that of electrode diathermy. Prediction of the "selective" effect is possible from a knowledge of the characteristic electrical constants of the body-substances at high frequencies, and by proper choice of wave-length the heating of a particular part might be favored over that of neighboring parts.In the second part of the paper, experimental work is described which carries verification of the formulas to shorter wave-lengths. Experiments on the heating of meat demonstrate the selective effect and its dependence upon wave-length. The heating of such substances as liver, heart, and the different parts of an egg, are examined experimentally as examples of the various determining factors that are involved.The theoretical explanation of the effects is considered satisfactory and further developments depend upon the results of in viva experiments with shorter wavelengths than those at present in general use.

Surface dangling bonds are a cause of B-type blinking in Si nanoparticles

Nanoscale ◽  
2015 ◽  
Vol 7 (8) ◽  
pp. 3737-3744 ◽  
Author(s):  
Nicholas P. Brawand ◽  
Márton Vörös ◽  
Giulia Galli
Keyword(s):  
Electronic Properties ◽  
First Principles ◽  
Charge Recombination ◽  
First Principles Calculations ◽  
Dangling Bonds ◽  
Si Nanoparticles ◽  
Recombination Dynamics

The electronic properties and charge recombination dynamics of oxidized Si nanoparticles containing surface dangling bonds are investigated using first principles calculations.

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