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 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.

Measurement on Thermal Radiation of Standard High-Temperature Blackbody Furnace in Visible Spectrum Range

2010 ◽  
Vol 663-665 ◽  
pp. 223-226
Author(s):  
Jian Bo Lei ◽  
Juan Chen ◽  
Zhen Wang ◽  
Yun Shan Wang
Keyword(s):  
High Temperature ◽  
Thermal Radiation ◽  
Radiation Intensity ◽  
Visible Spectrum ◽  
Radiation Wavelength ◽  
Spectrum Range ◽  
Bright Yellow ◽  
Blue Radiation ◽  
Blue Wavelength ◽  
Material Temperature

Based Plank’s radiation law, thermal radiation intensity depends on radiation wavelength and material temperature. As the increase of material temperature, thermal radiation wavelength will decrease from infrared waves, next to visible light, last to ultraviolet light. In order to research the spectral distribution of molten pool at different temperature in laser fabricating, thermal radiation of standard BF1400 blackbody furnace in National Institute of Metrology of China was measured by CCD technique. Its high-temperature cavity radiators glow which was dim red at 600 oC, bright red at 800 oC, yellowish red at 1000 oC, bright yellow at 1200 oC. The thermal radiation in visible spectrum range could be acquired by CCD, which was translated into grey data of red, green and blue radiation intensity. It was shown that grey gain at red, green and blue wavelength was different greatly as increase of blackbody temperature, extremely large at red wavelength, little at blue and green wavelength. When thermal radiation of molten metal pool at red, green and blue wavelength in laser fabricating was acquired to analyze the relation between spectrum and temperature, the green and blue wavelength will be good choose for its colorimetry temperature analysis.

scholarly journals Professional activists? Party activism among political staffers in parliamentary democracies

2021 ◽  
pp. 135406882110273
Author(s):  
Pieter Moens
Keyword(s):  
Theoretical Model ◽  
Survey Data ◽  
High Intensity ◽  
Supply And Demand ◽  
Parliamentary Democracies ◽  
Coalition Governments ◽  
Depth Analysis ◽  
Strong Commitment ◽  
Staff Recruitment

Although the position of the party on the ground has been weakened by cartelization, grassroots activists remain an important recruitment pool for political professionals. Based on unique survey data collected among the staff of 14 Belgian and Dutch parties (N = 1009), this article offers an in-depth analysis of party activism among this under-researched population. Introducing a new supply and demand framework, I argue that staff recruitment is shaped by candidate preferences (supply) and party preferences (demand). The findings demonstrate that most political staffers are high-intensity activists with a strong commitment to their party. Moreover, the theoretical model accurately predicts that non-activists are more common among policy and communication experts, ministerial staff, and those working for ideologically moderate parties. These findings show that paid staffers do not necessarily widen the gap between parties and activists. They also raise normative questions about internal congruence within parties in coalition governments.

Ferroelectric, piezoelectric, and dielectric properties of BiScO3-PbTiO3-Pb(Cd1/3Nb2/3)O3 ternary high temperature piezoelectric ceramics

2013 ◽  
Vol 114 (2) ◽  
pp. 027014 ◽  
Author(s):  
Tian-Long Zhao ◽  
Jianguo Chen ◽  
Chun-Ming Wang ◽  
Yang Yu ◽  
Shuxiang Dong
Keyword(s):  
High Temperature ◽  
Dielectric Properties ◽  
Piezoelectric Ceramics

Dielectric Properties of Solid Solutions of BiFeO3 with Pb(Ti, Zr)O3 at High Temperature and High Frequency

1968 ◽  
Vol 39 (1) ◽  
pp. 70-74 ◽  
Author(s):  
Robert T. Smith ◽  
Gary D. Achenbach ◽  
Robert Gerson ◽  
W. J. James
Keyword(s):  
High Temperature ◽  
Dielectric Properties ◽  
Solid Solutions ◽  
High Frequency

Radiothermal radiation method for aqueous solutions

2021 ◽  
Author(s):  
L.A. Morozova ◽  
S.V. Savel’ev
Keyword(s):  
Dielectric Properties ◽  
Alkali Metal ◽  
Thermal Radiation ◽  
Aqueous Solutions ◽  
Physical Properties ◽  
Dielectric Constants ◽  
Water Molecules ◽  
Absorption Coefficients ◽  
Basic Substance ◽  
High Dilutions

For the first time, an ultra-high-sensitivity method for measuring radio-thermal radiation was developed and used in practice in order to establish the difference in the physical properties of aqueous solutions of substances in the millimeter region of the spectrum. The method is used to study the dynamics of the dielectric properties of aqueous solutions depending on the composition of the base substance and its concentration. The dynamics of dielectric properties establishes a one-to-one correspondence between the number and concentration of ions of the dissolved basic substance contained in water and the number of water molecules involved in cooperative interaction, which gives a consistent microscopic picture of ion-water cooperative interactions in the studied aqueous solutions of K2SO4 and Cs2SO4. The density of water molecules perturbed by the ions of the base substance contained in the hydration shell at normal concentrations is proportional to the number of ions, while the transition to weaker solutions leads to the creation of multilayer hydration shells. This means that the number of perturbed water molecules, depending on the number of ions, increases according to a law different from linear. In accordance with the experimental data, the values of the absorption coefficients of aqueous solutions were determined in a wide range of concentrations for alkali metal sulfates. It is noted that alkali metal sulfates have physical properties that generalize the dynamics of dielectric constants depending on the concentration of the base substance. A monotonic increase in the values of the absorption coefficients of solutions with a decrease in the concentration of basic substances in the region of high dilutions was established with individual dynamics for each basic substance, reflecting the total hydration changes in salt solutions. Research has shown that the proposed method for measuring radio-thermal radiation fixes a significant difference in the values of the dielectric constants of aqueous solutions at high dilutions from their values for water.

Improvement of Dielectric Performance of a Prototype AlN High Temperature Chip-level Package

2011 ◽  
Vol 2011 (HITEN) ◽  
pp. 000052-000057 ◽  
Author(s):  
Liang-Yu Chen
Keyword(s):  
High Temperature ◽  
Dielectric Properties ◽  
High Temperatures ◽  
Substrate Surface ◽  
Substrate Material ◽  
Glass Coating ◽  
Temperature Dependent ◽  
High Temperature Electronics ◽  
Dielectric Performance ◽  
Parasitic Parameters

Aluminum nitride (AlN) has been proposed as a packaging substrate material for reliable high temperature electronics operating in a wide temperature range. However, it was discovered in a recent study that the dielectric properties of some commercial polycrystalline AlN materials change quite significantly with temperature at high temperatures. These material properties resulted in undesired large and temperature-dependent parasitic parameters for a prototype chip-level package based on an AlN substrate with the yttrium oxide dopant. This paper reports a method using a coating layer of a commercial thick-film glass on the AlN substrate surface to significantly reduce both the parasitic capacitances and parasitic conductances between neighboring inputs/outputs (I/Os) of a prototype AlN chip-level package. The parasitic parameters of 8-I/Os low power chip-level packages with the insulating glass coating were characterized at frequencies from 120 Hz to 1 MHz between room temperature and 500°C. These results were compared with the parameters of AlN packages without the glass coating. The results indicate that the parasitic capacitances and conductances between I/Os of the improved prototype AlN packages are significantly reduced and stable at high temperatures. The method using a glass coating provides a feasible way to mitigate the temperature dependence of dielectric properties of AlN and further utilize AlN as a reliable packaging substrate material for high temperature applications.

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