scholarly journals Тепловое излучение абсолютно черного тела, движущегося в равновесном газе фотонов

2021 ◽  
Vol 91 (7) ◽  
pp. 1075
Author(s):  
Г.В. Дедков ◽  
А.А. Кясов
Keyword(s):  
Thermal Radiation ◽  
Radiation Intensity ◽  
Thermal State ◽  
Black Body ◽  
The Body ◽  
Initial Moment ◽  
Quasi Stationary State ◽  
Photon Gas ◽  
Absolutely Black Body ◽  
Kinetics Of

The dynamics, kinetics of heat transfer and the intensity of thermal radiation of an absolutely black body with its own temperature T1 moving at an arbitrary speed in an equilibrium gas of photons with its own temperature T2 independent of time are considered. Formulas are obtained for the spectral-angular and total radiation intensity, as well as for other quantities in the rest frame of the body and in the frame of reference of the photon gas. It is shown that at the initial moment the radiation intensity of spherical and disk-shaped particles of the same radius depends differently on the speed of motion and the ratio of temperatures T1 and T2. Then a quasi-stationary thermal state of bodies is established with an effective temperature depending on the velocity and temperature T2, the intensity of thermal radiation does not depend on the shape, and the kinetic energy is transformed into radiation. The characteristic time for the establishment of a quasi-stationary state is many orders of magnitude shorter than the characteristic deceleration time.

scholarly journals A method for calculating the radiation power coefficients of black and gray bodies with dimensions commensurable with the radiated wavelengths

2021 ◽  
pp. 57-62
Keyword(s):  
Significant Contribution ◽  
Radiation Power ◽  
Black Body ◽  
The Body ◽  
Round Hole ◽  
Cutoff Wavelength ◽  
Integral Radiation ◽  
Absolutely Black Body ◽  
Square Hole

A technique is proposed and the calculations of the dependences of the emissivity of an abso-lute black body (BBB) on the size of the diaphragms of the emitting aperture are performed for hypothetical cases when the sizes of the diaphragms are commensurate with the emitted wavelengths, and the diaphragms are made of a dielectric opaque for radiation. The value of the cutoff wavelength  = 1.772A for the square aperture of the diaphragm was determined, where A is the side of the square and  = 1. 571D for the round hole. where D is the hole di-ameter, i.e. it is shown that the body cannot emit wavelengths λ greater than 1.772A in the case of a square hole and 1.571D in the case of a round hole. It is shown that if the “cut off” wavelengths made any significant contribution to the integral radiation of a blackbody with temperature T at standard diaphragm diameters (i.e., at diameters of much larger radiated wavelengths), then the emissivity of this body becomes less than unity and rapidly decreases when the size of the diaphragms is commensurate with . In these cases, such a body ceases to be an absolutely black body and the laws of Planck and Stefan–Boltzmann cannot be used to calculate the power of its radiation, but the technique proposed in this work can be used.

scholarly journals Широкополосное излучение малых диэлектрических частиц

2020 ◽  
Vol 128 (9) ◽  
pp. 1323
Author(s):  
С.Ш. Рехвиашвили
Keyword(s):  
High Temperature ◽  
Dielectric Properties ◽  
Theoretical Model ◽  
Thermal Radiation ◽  
Radiation Intensity ◽  
High Intensity ◽  
Dimensional Effect ◽  
Dielectric Particles ◽  
Photon Gas

A qualitatively new theoretical model of broadband ("white") thermal radiation of small dielectric particles is proposed. It is suggested and justified that the high intensity of this radiation may be due not to an extremely high temperature, but to the dielectric properties of the material and/or the dimensional effect of thermal radiation. The calculation of the radiation intensity of a blackbody and a spherical dielectric particle depending on the photon gas dimension is performed.

scholarly journals DESCRIPTIONS OF SOME LEPIDOPTEROUS LARVÆ

1888 ◽  
Vol 20 (7) ◽  
pp. 134-136
Author(s):  
W. M. Beutenmuller
Keyword(s):  
Black Body ◽  
The Body

Datana integerrima, Gr. & Rob.Before Last Moult.—Head and cervical shield shining jet black. Body deep reddish brown, with three very fine, narrow, sordid white stripes along each side, and a broader one below the spricles, which are black, and another stripe along the middle of the venter. Thoracic feet, extremities of abdominal legs and anal legs jet black, shining. The body is also covered with sordid white hairs. Length 32 mm.

scholarly journals Looking Like People; Feeling Like People: The Black Body, Dress and Aesthetic Therapy in the Caribbean

2014 ◽  
Vol 6 (4) ◽  
pp. 857-872
Author(s):  
Marsha Pearce
Keyword(s):  
Conceptual Framework ◽  
New World ◽  
Black Body ◽  
The Body ◽  
Therapeutic Discourse ◽  
Black Caribbean ◽  
Black Bodies ◽  
The Caribbean ◽  
Bodily Practice ◽  
Instrumental Role

In the Caribbean, the practice of getting dressed matters because it is a practice of attending to the body. Under a colonial regime, black bodies were ill-treated and selves were negated. Clothing played an instrumental role in the abuse of bodies and the stripping of a sense of wellbeing. Attire was one key way of demarcating master and slave and rendering some members of society null and void. Enslaved Africans, who were forcibly brought across the Atlantic to the New World, were considered chattel or commodities rather than people and clothes functioned in a way that reinforced that notion. Yet, dress became a strategy of subversion – of making chattel, property or ‘non-people’ look like people. The enslaved recognised that, through clothes, it was possible to look and feel free. Today that legacy remains. Clothing is seen not only as that which can make a people ‘look like people’ but also feel like people – clothing sets up a specific structure of feeling. This paper pivots on notions of looking and feeling like people while deploying Joanne Entwistle’s conceptual framework of dress as situated bodily practice. The article locates its investigation in the Caribbean, examining the philosophy and practice of Trinidadian clothing designer Robert Young. The article establishes him as a source of aesthetic therapeutic solutions in the Caribbean. It argues that his clothing designs produce a therapeutic discourse on the Black Caribbean body – a discourse, which facilitates a practice of getting dressed that gives a sense of agency, self-empowerment and psychic security even if that sense is embodied temporarily; lasting perhaps only as long as the garment is worn.

scholarly journals The Kinetics of Peroxynitrite on Insulin Nitration Damage

2020 ◽  
Author(s):  
Congxiao Zhang ◽  
Fusheng Sun ◽  
Congjiang Zhang ◽  
Yunjing Luo
Keyword(s):  
Activation Energy ◽  
Biological Activity ◽  
Glucose Metabolism ◽  
Rate Constants ◽  
The Body ◽  
Stopped Flow ◽  
Tyrosine Nitration ◽  
Protein Nitration ◽  
Physiological Conditions ◽  
Kinetics Of

Abstract Background: Insulin is one of the most important versatile hormones that is central to regulating the energy and glucose metabolism in the body. There has been accumulating evidence supporting that diabetes was associated with peroxynitrite and protein nitration, and insulin nitration induced by peroxynitrite affected its biological activity. Methods: In this paper, the kinetics of insulin nitration by peroxynitrite in physiological conditions was studied by the stopped flow technique. Results: We determined the values of the reactive rate constants of peroxynitrite decomposition and peroxynitrite-induced tyrosine nitration in the presence of insulin. The activation energy of peroxynitrite decomposition and 3-nitrotyrosine yield in the presence of insulin is 48.8 kJ·mol−1 and 42.7 kJ·mol−1 respectively. Conclusions: It is inferred that the glutamate residue of insulin accelerated peroxynitrite decomposition and tyrosine nitration by reducing the activation energy of reactions. The results could be beneficial for exploring the molecular mechanism of diabetes and offering a new target for diabetes therapies.

scholarly journals Anticipatory Postural Adjustments in Dart Throwing

2013 ◽  
Vol 37 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Grzegorz Juras ◽  
Kajetan Słomka
Keyword(s):  
Repeated Measures ◽  
Training Session ◽  
Motor Task ◽  
Anticipatory Postural Adjustments ◽  
The Body ◽  
Target Size ◽  
Postural Adjustments ◽  
Dart Throwing ◽  
Task Parameters ◽  
Kinetics Of

The aim of this study was to explore the effects of accuracy constraints on the characteristics of anticipatory postural adjustments (APA) in a task that involves a movement consisting of a controlled phase and a ballistic phase. It was hypothesized that APA scaling with task parameters (target size) would be preserved even when the task is performed by muscles that have no direct effects on APA. Sixteen healthy right handed subjects participated in the study. All participants had no prior experience in dart throwing. Subjects’ average age was 24.1 ± 1.9 years. A force platform and a motion capture system were used to register kinetics of the body and kinematics of the throwing arm and throwing accuracy. The experiment consisted of six series of twenty consecutive dart throws to a specified target. Target sizes (T2-T6) were set at 25%, 50%, 75%, 125% and 150% of target 1 (T1) initially set as the spread of the last 20 throws in a 50 throw training session. This allowed to distinguish six indexes of difficulty (ID’s) ranging from 2,9 to 5,9. A one-way ANOVA for repeated measures was used for statistical analysis. Results of ANOVA showed a significant effect of target size at Constant Error but no effect at APA time. There were also no significant differences between hit and miss throws. From a control perspective, it can be stated that changes in central commands did not lead to changes in APA time in the analyzed motor task.

scholarly journals Amniotic fluid fibronectin. Characterization and synthesis by cells in culture.

1978 ◽  
Vol 78 (3) ◽  
pp. 701-715 ◽  
Author(s):  
E Crouch ◽  
G Balian ◽  
K Holbrook ◽  
D Duksin ◽  
P Bornstein
Keyword(s):  
Amniotic Fluid ◽  
Matrix Protein ◽  
Sodium Dodecyl ◽  
Basement Membranes ◽  
The Body ◽  
Connective Tissues ◽  
Human Amniotic Fluid ◽  
Cold Insoluble Globulin ◽  
Kinetics Of

A glycoprotein immunologically related to plasma cold-insoluble globulin (CIG) and fetal skin fibroblast fibronectin has been purified from second-trimester human amniotic fluid. This protein (amniotic fluid fibronectin) migrated more slowly than CIG on sodium dodecyl sulfate gel electrophoresis and showed greater polydispersity which could result, at least in part, from heterogeneity in glycosylation. Cloned human amniotic fluid epithelioid and fibroblastic cells synthesized and secreted a protein with similar properties into the culture medium. Fibronectin was shown to be associated with the pericellular and extracellular matrix of cultured amniotic fluid cells by immunofluorescence, lactoperoxidase-catalyzed iodination, and labeling with ferritin-conjugated antibodies. The kinetics of secretion of the protein were consistent with its role as a matrix protein. We anticipate that amniotic fluid fibronectin will prove to be the same protein which elsewhere in the body is incorporated into connective tissues and basement membranes. Amniotic fluid could, therefore, serve as a convenient source of in vivo synthesized fibronectin for biological and structural studies.

scholarly journals On the role of evaporative wind in precataclysmic binaries (PCB)

1997 ◽  
Vol 180 ◽  
pp. 131-131
Author(s):  
I. Pustylnik ◽  
V. Pustynski
Keyword(s):  
Optical Depth ◽  
Black Body ◽  
Temperature Inversion ◽  
Light Curves ◽  
Gravitational Acceleration ◽  
Cool Component ◽  
First Results ◽  
The Mean ◽  
Absolutely Black Body ◽  
Definition Of

Recently we have started a systematic reevaluation of the existing observational methods of analysis hitherto applied to PCB-s. Here we report the first results of our investigations. The improved Napier's algorithm (Napier, 1968) to model the light curves of PCB (with the aid of the set of our computer programs in Turbo Pascal) is used. The source function is taken either from Sobieski (1965) or Strittmatter (1974). The entire luminosity received from the cool companion is calculated by integration of the emerging radiation over its disk; contributions from the illuminated and unilluminated portions of the disk are accounted for. We assume: a) the validity of the LTE in the photosphere of cool component, b) constancy of the monochromatic to mean absorption coefficient ratio within the photosphere, c) the hot star radiates as the absolutely black body, d) there are no other effects influencing the light curve except for the reflection effect. We have modelled the light curves of EC11575-1845 (Chen et al (1995). The analysis of the temperature distributions in the heated photosphere indicates the occurence of the temperature inversion. To make a rough estimate of physical conditions which can induce generation of evaporative wind we have used two criteria: i) the temperature inversion, ii) relation between radiative pressure and the effective gravitational acceleration. We assumed the density varies with the height in the atmosphere of the illuminated star as ρ ≃ exp(−Φ/RgT), Φ - being the Roche potential. The integral equation following from the definition of the mean optical depth was solved numerically to establish the relation between the mean optical depth and the distance in the atmosphere. We find the characteristic height scale for X-ray and EUV radiation is ∼ 106 − 107cm (for concentration of particles ∼ 1013cm−3). To check the validity of the ii) criterium we used a simplified model of radially expanding evaporative stellar wind and mass flux J conservation condition along the stream tube of the form J ∼ ρsvsrs2 exp −(Φ/RgT) (Pustylnik (1995)) and found M ∼ 10−12–10−11M/y. Although mass loss of such a rate cannot compete with the effects of the angular momentum loss which is responsible for a secular orbital shrinkage, the evaporative wind should significantly alter the structure of the the cool irradiated components.

Observations in the Skin Pigment and Amoebocytes, and the Occurrence of Phenolases in the Coelomic Fluid of Holothuria Forskali Delle Chiaje

1953 ◽  
Vol 31 (3) ◽  
pp. 529-539 ◽  
Author(s):  
Norman Millott
Keyword(s):  
Body Wall ◽  
Black Body ◽  
The Body ◽  
Coelomic Fluid ◽  
Histological Evidence ◽  
Oxidase System ◽  
Complete Investigation ◽  
Skin Pigment

The black body-wall pigment of Holothuria forskali shows the characteristics of melanin.From histological evidence it appears that the pigment is formed in association with the amoebocytes of the coelomic fluid, which eliminate the pigment in the body wall.The amoebocytes contain a phenolase system, distinct from the cytochromecytochrome oxidase system, with the properties of tyrosinase.The relation of these findings to those of a preceding and more complete investigation into melanogenesis in Diadema is discussed.

Sign in / Sign up

Export Citation Format

Share Document