g-Values for γ-irradiated water as a function of temperature

1990 ◽  
Vol 68 (5) ◽  
pp. 712-719 ◽  
Author(s):  
A. John Elliot ◽  
Monique P. Chenier ◽  
Denis C. Ouellette
Keyword(s):  
Experimental Data ◽  
Hydrogen Peroxide ◽  
Hydroxyl Radical ◽  
Temperature Dependence ◽  
Atomic Hydrogen ◽  
Molecular Hydrogen ◽  
Hydrated Electron ◽  
Temperature Range ◽  
Increasing Temperature

The g-values of primary species formed in the γ-radiolysis of water have been estimated for the temperature range 25–300 °C. The g-values for the hydrated electron, the hydroxyl radical, and molecular hydrogen all increase approximately 50% over this temperature range. The g-values for the minor products, hydrogen peroxide and atomic hydrogen, probably also increase with temperature; however, there is evidence from some of the experimental data which suggests that these g-values may slightly decrease with increasing temperature. Keywords: radiolysis, g-values, temperature dependence.

Radiolysis studies on the corrosion inhibitors 1 -hexyn-3-ol, cinnamonitrile, and 1,3-diethyl-2-thiourea

1995 ◽  
Vol 73 (12) ◽  
pp. 2137-2142 ◽  
Author(s):  
A.J. Elliot ◽  
M.P. Chenier ◽  
D.C. Ouellette
Keyword(s):  
Hydrogen Atom ◽  
Hydroxyl Radical ◽  
Temperature Dependence ◽  
Rate Constant ◽  
Rate Constants ◽  
Corrosion Inhibitors ◽  
Hydrated Electron

In this publication we report: (i) the rate constants for reaction of the hydrated electron with 1-hexyn-3-ol ((8.6 ± 0.3) × 108 dm3 mol−1 s−1 at 18 °C), cinnamonitrile ((2.3 ± 0.2) × 1010 dm3 mol−1 s−1 at 20 °C), and 1,3-diethyl-2-thiourea ((3.5 ± 0.3) × 108 dm3 mol−1 s−1 at 22 °C). For cinnamonitrile and diethylthiourea, the temperature dependence up to 200 °C and 150 °C, respectively, is also reported; (ii) the rate constants for the reaction of the hydroxyl radical with 1-hexyn-3-ol ((5.5 ± 0.5) × 109 dm3 mol−1 s−1 at 20 °C), cinnamonitrile ((9.2 ± 0.3) × 109 dm3 mol−1 s−1 at 21 °C), and diethylthiourea ((8.0 ± 0.8) × 108 dm3 mol−1 s−1 at 22 °C). For cinnamonitrile, the temperature dependence up to 200 °C is also reported; (iii) the rate constant for the hydrogen atom reacting with 1-hexyn-3-ol ((4.3 ± 0.4) × 109 dm3 mol−1 s−1 at 20 °C). Keywords: radiolysis, corrosion inhibitors, rate constants.

scholarly journals Температурная зависимость ширины запрещенной зоны монокристаллов MnAgIn-=SUB=-7-=/SUB=-S-=SUB=-12-=/SUB=-

2019 ◽  
Vol 53 (12) ◽  
pp. 1621
Author(s):  
И.В. Боднарь ◽  
Б.Т. Чан ◽  
В.Н. Павловский ◽  
И.Е. Свитенков ◽  
Г.П. Яблонский
Keyword(s):  
Experimental Data ◽  
Temperature Dependence ◽  
Band Gap ◽  
Single Crystals ◽  
Spinel Structure ◽  
Semiconductor Materials ◽  
Transmittance Spectra ◽  
Temperature Range

AbstractMnAgIn_7S_12 single crystals 16 mm in diameter and ~40 mm in length are grown by planar crystallization of the melt. It is shown that the material grown crystallizes with the formation of the cubic spinel structure. From the transmittance spectra recorded in the region of fundamental absorption in the temperature range 10–320 K, the band gap E _ g of the single crystals and its temperature dependence are determined. The dependence has a shape typical of most semiconductor materials: as the temperature is lowered, the band gap E _ g increases. A calculation is carried out, and it is shown that the calculated values are in agreement with the experimental data.

The flow of liquids with a temperature anomaly of viscosity

2003 ◽  
Vol 3 ◽  
pp. 232-245
Author(s):  
V.N. Kireev ◽  
S.F. Urmancheev
Keyword(s):  
Fluid Flow ◽  
Temperature Dependence ◽  
Temperature Anomaly ◽  
Numerical Study ◽  
Liquid Sulfur ◽  
Temperature Range ◽  
External Conditions ◽  
Increasing Temperature ◽  
Viscosity Dependence

For the vast majority of liquids, viscosity is a function that decreases monotonically with increasing temperature. However, a number of substances in which processes of polymerization and depolymerization can occur in a certain temperature range have a viscosity with a nonmonotonic temperature dependence. This dependence, for example, is characteristic of liquid sulfur. In this paper we present the results of a numerical study of the features of the flow of a liquid with a certain model nonmonotonic viscosity dependence on the temperature. The formation of a ”viscous barrier“ that determines the nature of the fluid flow in the channel is established. The main regularities of the flow are determined depending on the parameters of the viscous anomaly and external conditions.

On the temperature dependence of the primary yield and the product Gεmax of hydrated electrons in the low-LET radiolysis of liquid water

2002 ◽  
Vol 80 (7) ◽  
pp. 767-773 ◽  
Author(s):  
Jintana Meesungnoen ◽  
Jean-Paul Jay-Gerin ◽  
Abdelali Filali-Mouhim ◽  
Samlee Mankhetkorn
Keyword(s):  
Experimental Data ◽  
Dielectric Constant ◽  
Temperature Dependence ◽  
Extinction Coefficient ◽  
Liquid Water ◽  
Hydrated Electron ◽  
Molar Extinction Coefficient ◽  
Water Radiolysis ◽  
Geminate Recombination ◽  
Primary Yield

Monte-Carlo simulations are performed to calculate the temperature dependence of the primary hydrated electron yield (Geaq-) for liquid water irradiated by low linear-energy-transfer radiation (LET ~ 0.3 keV µm–1) in the range 25–325°C. Calculations are carried out by taking properly into account the effect of the time and temperature dependencies of the water dielectric constant on the electron–cation geminate recombination. Our computed Geaq- values slightly increase with increasing temperature, in good agreement with experiment. The product Geaq- εmax(eaq-), estimated by using existing experimental data of the maximum molar extinction coefficient εmax(eaq-), remains nearly constant or slightly increases, depending on the temperature dependence chosen for εmax. Our Geaq-εmax(eaq-) values compare generally well with most experimental data, as well as with the predictions of deterministic diffusion-kinetic model calculations. Moreover, our results indicate that the static dielectric constant of water (εs) does not play any significant role on the electron–cation recombination at early times. Such a finding is inconsistent with the interpretation, proposed by certain authors in the literature, that Geaq- should in fact decrease as temperature is increased because of an increased electron–cation geminate recombination due to a lowering of εs. Finally, the temperature dependence of the hydrated electron yields, calculated at various times between 10 ps and 1 µs, shows that at low LET, the time required to establish homogeneous chemistry in the bulk of the solution is ~10–6 s in the range ~25–100°C, and that this time diminishes to ~10–7 s at higher temperatures. Key words: liquid water, radiolysis, temperature, hydrated electron (eaq-), radiolytic yields, electron–cation geminate recombination, dielectric constant, molar extinction coefficient of eaq-, homogenization time.

Temperature dependence of heats of vaporization of saturated hydrocarbons C5-C8; Experimental data and an estimation method

1979 ◽  
Vol 44 (3) ◽  
pp. 637-651 ◽  
Author(s):  
Vladimír Majer ◽  
Václav Svoboda ◽  
Slavoj Hála ◽  
Jiří Pick
Keyword(s):  
Experimental Data ◽  
Temperature Dependence ◽  
Estimation Method ◽  
Saturated Hydrocarbons ◽  
Heat Of Vaporization ◽  
Temperature Range ◽  
Entropy Of Vaporization ◽  
Heats Of Vaporization

Heats of vaporization of a group of 10 alkanes C6-C8 and 2 cycloalkanes were measured in a temperature range of 25-80 °C. By combining the obtained results with selected literature data, a set of very accurate values of heats of vaporization as functions of temperature was made up for 22 saturated C5-C8 hydrocarbons. This set was employed for the verification of the proposed estimation method for the determination of heat of vaporization which is based on the principle of combination of a contribution method with constant entropy-of-vaporization rules. In this way it is then possible to estimate heats of vaporization of C4-C9 alkanes with an error lower than 0.5%.

scholarly journals Особенности доменной структуры гексаферрита BaFe-=SUB=-12-=/SUB=-O-=SUB=-19-=/SUB=- вблизи температуры Кюри

2020 ◽  
Vol 62 (7) ◽  
pp. 1050
Author(s):  
А.А. Безлепкин ◽  
С.П. Кунцевич
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Domain Walls ◽  
Physical Mechanism ◽  
Structural Features ◽  
Temperature Range ◽  
The Difference ◽  
Increasing Temperature ◽  
Curie Temperature Tc ◽  
Ordered State

The structural features of the domain walls of the BaFe12O19 hexaferrite near the Curie temperature TC = 724 K were studied. The studies were performed on single-crystal samples in an alternating magnetic field with a frequency of 73 MHz and 71 MHz with a constant magnetic field in the range 0–0.25 kOe. In BaFe12O19 at a temperature of T1 = 716 K, the magnetic structure of the domain walls changes – the Bloch walls transform into linear walls with increasing temperature. The value ΔТ = Tc – T1≈8 K. The physical mechanism considered in the work, which determines the difference between the temperature range of the existence of the magnetically ordered state and the temperature range of the existence of the Bloch domain walls, is consistent with experimental results. The estimated calculation of the criterion for the transition of the Bloch domain wall to a linear wall at T1 = 716 K corresponds to the obtained experimental data.

Temperature dependence of the shape of the cellodextrins in aqueous solution

1967 ◽  
Vol 45 (20) ◽  
pp. 2363-2367 ◽  
Author(s):  
M. Ihnat ◽  
D. A. I. Goring
Keyword(s):  
Aqueous Solution ◽  
Temperature Dependence ◽  
Computational Methods ◽  
Negative Temperature ◽  
Temperature Range ◽  
Temperature Coefficients ◽  
Increasing Temperature

Intrinsic viscosities of the cellodextrins, cellobiose to cellohexaose, were measured in aqueous solution at temperatures from 25 to 70 °C. Axial ratios were determined using the Einstein–Simha viscosity relation and the computational methods developed previously. The results showed that the oligomers are fully extended over this temperature range and that the negative temperature coefficients of the intrinsic viscosities are caused by the dehydration of the molecules with increasing temperature.

TEMPERATURE DEPENDENCE OF THE RAMAN FREQUENCIES IN THE γ AND β PHASES OF SOLID NITROGEN

2010 ◽  
Vol 24 (31) ◽  
pp. 6069-6078 ◽  
Author(s):  
H. YURTSEVEN ◽  
T. TUNAY
Keyword(s):  
Experimental Data ◽  
Frequency Shift ◽  
Temperature Dependence ◽  
Interaction Mechanism ◽  
Internal Mode ◽  
Unusual Behavior ◽  
Self Energy ◽  
Solid Nitrogen ◽  
Increasing Temperature ◽  
Lattice Modes

We study here the Raman frequencies of the lattice modes (γ and β phases) and of an internal mode (γ phase) as a function of temperature in solid nitrogen. The frequency shift derived from the anharmonic self energy, is fitted to the experimental data for the Raman frequencies of the modes considered here in the γ and β phases of solid nitrogen. From our fittings, we find that the Raman frequencies of the lattice modes decrease, whereas those of the internal mode increase with increasing temperature in solid nitrogen. The unusual behavior of the internal mode indicates that the interaction mechanism should be different in relation to the anharmonicity in the γ phase of solid nitrogen.

scholarly journals WETTING ANGLE POLYTERMES FOR LEAD-SODIUM MELTS ON REFRACTORY METALS

2020 ◽  
pp. 113-119
Author(s):  
Барасби Сулейманович Карамурзов ◽  
Руслан Азаевич Кутуев ◽  
Мурат Хажисмелович Понежев ◽  
Виктор Адыгеевич Созаев ◽  
Астемир Хусенович Шерметов ◽  
...  
Keyword(s):  
Contact Angle ◽  
Stainless Steel ◽  
Temperature Dependence ◽  
Refractory Metals ◽  
Wetting Angle ◽  
Temperature Range ◽  
Drop Method ◽  
Pure Helium ◽  
Increasing Temperature

Методом лежащей капли изучена температурная зависимость краевого угла смачивания сплавов Pb - Na разной концентрации на подложках из Co - Cr, Ni - Cr, нержавеющей стали 251892. Измерения проводились методом лежащей капли в широком интервале температур от 359°С до 800 °С в атмосфере чистого марки А. Показано, что значение угла смачивания уменьшается с увеличением температуры, наблюдаются пороги смачивания. The temperature dependence of the contact angle for Pb - Na melts of different concentrations on Co - Cr , Ni - Cr and stainless steel 25X18H9C2 substrate was studied by the method of a lying drop. Measurements were carried out by a lying drop method in the temperature range from 359 to 800 °C in an atmosphere of pure helium grade A. It is shown that the value of the wetting angle decreases with increasing temperature, wetting thresholds are observed.

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