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121.
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123.
Classification and performance capability of electric are linear plasmatrons are presented. The results of investigation into convective and radiative heat transfer in the discharge channel of a plasmatron are reported. The radiative heat transfer dominates both in the structure of heat losses and in the formation of discharge volt-ampere characteristic at the initial region of the flow. Relations to calculate heat losses by radiation are given. Radiative convective interaction at the arc boundary is shown to play a substantial role for high-current discharges stabilized by axial vortex gas flow. It is shown that the calculation of convective heat transfer at the turbulent region of the flow may be carried out by flow averaged parameters. 相似文献
124.
A. V. Fokin Yu. N. Studnev A. I. Rapkin D. A. Sultanbekov T. M. Potarina 《Russian Chemical Bulletin》1984,33(2):372-375
Conclusions The corresponding acyl fluorides are formed as the result of reacting 1,1,2-trifluoro-2-chloroethyldiethylamine with fluorocarboxylic acids.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 411–415, February, 1984. 相似文献
125.
126.
Possibilities of using torsional oscillations for measuring viscoelastic properties of liquids are discussed. The theory of
torsional oscillations of an elastic tube filled with the media to be investigated possessing viscosity and shear elasticity
is developed. It is shown that to determine a complex shear modulus it is sufficient to determine the resonance frequency
and Q-factor of torsional oscillations. An experimental installation and the results of measurements of viscoelastic modulus
of glycerin and oil of one oilfield within the temperature range from −10° to 60°C are given. The experimental installation
allows measuring a viscoelastic modulus within the range of acoustic logging frequencies (10–20 kHz). The obtained results
are compared with the results of rheometric measurements. 相似文献
127.
The six-vertex model, or the square ice model, with domain wall boundary conditions (DWBC) has been introduced and solved for finite N by Korepin and Izergin. The solution is based on the Yang–Baxter equations and it represents the free energy in terms of an N × N Hankel determinant. Paul Zinn–Justin observed that the Izergin– Korepin formula can be re-expressed in terms of the partition function of a random matrix model with a nonpolynomial interaction. We use this observation to obtain the large N asymptotics of the six-vertex model with DWBC in the disordered phase. The solution is based on the Riemann–Hilbert approach and the Deift–Zhou nonlinear steepest descent method. As was noticed by Kuperberg, the problem of enumeration of alternating sign matrices (the ASM problem) is a special case of the six-vertex model. We compare the obtained exact solution of the six-vertex model with known exact results for the 1, 2, and 3 enumerations of ASMs, and also with the exact solution on the so-called free fermion line. We prove the conjecture of Zinn–Justin that the partition function of the six-vertex model with DWBC has the asymptotics, as N → ∞, and we find the exact value of the exponent κ.The first author is supported in part by the National Science Foundation (NSF) Grant DMS-0354962. 相似文献
128.
S. B. Vakhrushev I. V. Golosovsky E. Yu. Koroleva A. A. Naberezhnov N. M. Okuneva O. P. Smirnov A. V. Fokin M. Tovar M. Glazman 《Physics of the Solid State》2008,50(8):1548-1554
This paper reports on the results of the investigation into the thermal evolution of the structure and dielectric properties of Na1 ? x K x NO2 solid solutions (x = 0, 0.05, 0.10) embedded in porous glass with an average pore diameter of 70 ± 10 Å in the range 300–447 K, i.e., in the ferro-and paraelectric phases. The structural properties of the bulk and nanostructured materials are compared. It is shown that the introduction of small amounts of potassium brings about a noticeable change in the intensity ratio of the elastic Bragg peaks, while leaving the space group characterizing the structure of these nanocomposites unaffected. An increase in the potassium fraction does not result in a substantial decrease in the phase transition point. Measurements of the dielectric response have revealed that an increase in the potassium content gives rise to a marked “hardening” of the lattice in the premelting state, which reduces dielectric losses. 相似文献
129.
Oana Moncea Juan Casanova‐Chafer Didier Poinsot Lukas Ochmann Clve D. Mboyi Houssein O. Nasrallah Eduard Llobet Imen Makni Molka ElAtrous Stphane Brands Yoann Rousselin Bruno Domenichini Nicolas Nuns Andrey A. Fokin Peter R. Schreiner Jean‐Cyrille Hierso 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(29):10038-10043
Diamondoids, sp3‐hybridized nanometer‐sized diamond‐like hydrocarbons (nanodiamonds), difunctionalized with hydroxy and primary phosphine oxide groups, enable the assembly of the first sp3‐C‐based chemical sensors by vapor deposition. Both pristine nanodiamonds and palladium nanolayered composites can be used to detect toxic NO2 and NH3 gases. This carbon‐based gas sensor technology allows reversible NO2 detection down to 50 ppb and NH3 detection at 25–100 ppm concentration with fast response and recovery processes at 100 °C. Reversible gas adsorption and detection is compatible with 50 % humidity conditions. Semiconducting p‐type sensing properties are achieved from devices based on primary phosphine–diamantanol, in which high specific area (ca. 140 m2 g?1) and channel nanoporosity derive from H‐bonding. 相似文献
130.
A new approach is proposed to explain the strong difference between the induction periods (nucleation time-lags) obtained from nucleation rate measurements and from crystal growth experiments for lithium silicate glasses; and their similar magnitude for a Na2O · 2CaO · 3SiO2 glass. For these two glass families, the time-lags for nucleation estimated from crystal growth kinetics were compared with those directly obtained from nucleation experiments. A theoretical analysis was performed employing analytical solutions of the Frenkel-Zeldovich equation. In such analysis, the frequently assumed condition of size-independence of the thermodynamic properties of the crystallites was used. Provided this assumption is correct, time-lag data obtained in the two above mentioned ways should coincide. Consequently the significant difference between the values of nucleation time-lag for lithium silicate glasses from nucleation and growth data gives a strong indirect evidence for the deviation of the properties of critical nuclei from the respective parameters characterizing the state of the newly evolving macrophase. For Na2O · 2CaO · 3SiO2 glass at intermediate stages of crystallization we show that the average composition of the growing crystals is close to that of the near-critical nuclei. The fact that the nucleation and growth rates of this soda-lime-silica glass refer to the same phase provides an explanation for the similarity of the induction periods estimated from nucleation and growth experiments. 相似文献