PRESSURE-INDUCED INFRARED ABSORPTION OF HYDROGEN AND HYDROGEN – FOREIGN GAS MIXTURES IN THE RANGE 1500–5000 ATMOSPHERES

1958 ◽  
Vol 36 (1) ◽  
pp. 88-103 ◽  
Author(s):  
W. F. J. Hare ◽  
H. L. Welsh
Keyword(s):  
Absorption Coefficient ◽  
Infrared Absorption ◽  
Room Temperature ◽  
Pure Hydrogen ◽  
Vibrational Transition ◽  
Absorption Process ◽  
Quadrupole Interactions ◽  
Relative Kinetic ◽  
Very High ◽  
Absorption Of Hydrogen

The pressure-induced infrared absorption of hydrogen was studied in pure hydrogen and in hydrogen–helium, hydrogen–argon, and hydrogen–nitrogen mixtures at pressures up to 5000 atm. at room temperature. The integrated absorption coefficient can be expressed in the form α1ρaρp + α2ρaρp2 over the whole range of densities (ρa = density of H2, ρp = density of the perturbing gas, [Formula: see text] in the mixture experiments). The coefficient α2 is much smaller than predicted from the effect of finite molecular volumes; this is interpreted as a partial cancellation of the induced moments in ternary collisions. The splitting of the Q branch of the fundamental, which is due to the participation of the relative kinetic energies of the colliding molecules in the absorption process, increases linearly with the density because of ternary collisions; a more rapid increase observed at very high densities is not yet explained. The components of the overtone and double vibrational transition, like the QQ and S components of the fundamental, show no splitting or broadening with increasing density; these absorptions are believed to be due to quadrupole interactions while the QP and QR components of the fundamental are due to overlap interactions.

INDUCED INFRARED ABSORPTION IN HYDROGEN AND HYDROGEN - FOREIGN GAS MIXTURES AT PRESSURES UP TO 1500 ATMOSPHERES

1954 ◽  
Vol 32 (4) ◽  
pp. 291-312 ◽  
Author(s):  
D. A. Chisholm ◽  
H. L. Welsh
Keyword(s):  
Kinetic Energy ◽  
Absorption Band ◽  
Absorption Coefficient ◽  
Infrared Absorption ◽  
High Frequency ◽  
Absorption Process ◽  
Rate Of Increase ◽  
Frequency Components ◽  
Relative Kinetic ◽  
Gas Pressures

The pressure-induced fundamental infrared absorption band of hydrogen has been investigated in the pure gas and in hydrogen–helium, hydrogen–nitrogen, and hydrogen–argon mixtures for gas pressures up to 1500 atm. and temperatures in the range 80°–376°K. At the higher densities the rate of increase of the integrated absorption coefficient with density is anomalously large; this effect is interpreted in terms of finite molecular volumes. The Q branch has been shown to consist of three components QP, Qq, and QR. The separation of the maxima in the low- and high-frequency components, QP and QR, depends on the perturbing gas and increases linearly with its density; the separation and relative intensities of the components are also strongly dependent on the temperature. It is proposed that this splitting of the Q branch is caused by the participation of the relative kinetic energy of the colliding molecules in the absorption process for collisions in the region of overlap forces. The Qq component and the S lines show no splitting and are probably produced by collisions in the region of quadrupole interaction.

scholarly journals Infrared Absorption and Its Sources of CdZnTe at Cryogenic Temperature

2022 ◽  
Author(s):  
Hiroshi Maeshima ◽  
Kosei Matsumoto ◽  
Yasuhiro Hirahara ◽  
Takao Nakagawa ◽  
Ryoichi Koga ◽  
...  
Keyword(s):  
Absorption Coefficient ◽  
Infrared Absorption ◽  
Cryogenic Temperature ◽  
Room Temperature ◽  
Wavelength Region ◽  
Room Temperature Resistivity ◽  
Absorption Model ◽  
Acceptor Level ◽  
Absorption Coefficients ◽  
Temperature Resistivity

AbstractTo reveal the causes of infrared absorption in the wavelength region between electronic and lattice absorptions, we measured the temperature dependence of the absorption coefficient of p-type low-resistivity ($$\sim 10^2~ \Omega \mathrm{cm}$$ ∼ 10 2 Ω cm ) CdZnTe crystals. We measured the absorption coefficients of CdZnTe crystals in four wavelength bands ($$\lambda =6.45$$ λ = 6.45 , 10.6, 11.6, 15.1$$~\mu $$ μ m) over the temperature range of $$T=8.6$$ T = 8.6 -300 K with an originally developed system. The CdZnTe absorption coefficient was measured to be $$\alpha =0.3$$ α = 0.3 -0.5 $$\mathrm{cm}^{-1}$$ cm - 1 at $$T=300$$ T = 300 K and $$\alpha =0.4$$ α = 0.4 -0.9 $$\mathrm{cm}^{-1}$$ cm - 1 at $$T=8.6$$ T = 8.6 K in the investigated wavelength range. With an absorption model based on transitions of free holes and holes trapped at an acceptor level, we conclude that the absorption due to free holes at $$T=150$$ T = 150 -300 K and that due to trapped-holes at $$T<50$$ T < 50 K are dominant absorption causes in CdZnTe. We also discuss a method to predict the CdZnTe absorption coefficient at cryogenic temperature based on the room-temperature resistivity.

INFRARED ABSORPTION OF DEUTERIUM INDUCED BY INTERMOLECULAR FORCES

1965 ◽  
Vol 43 (5) ◽  
pp. 793-799 ◽  
Author(s):  
S. Paddi Reddy ◽  
C. W. Cho
Keyword(s):  
Absorption Band ◽  
Absorption Coefficient ◽  
Infrared Absorption ◽  
Room Temperature ◽  
Intermolecular Forces ◽  
Absorption Coefficients ◽  
Fundamental Band ◽  
Molecular Parameters ◽  
The Individual ◽  
Gas Pressures

The pressure-induced fundamental infrared absorption band of deuterium has been investigated in the pure gas for gas pressures up to 250 atm at room temperature. The binary and ternary absorption coefficients were determined from the integrated absorption coefficients of the fundamental band at different densities of the gas. The splitting of the Q branch into two well-resolved components QP and QR was observed; the contours also exhibit pronounced S(0) and S(2) components with an indication of the S(1) and O(2) components. The existing theory and the available molecular parameters of deuterium were used to calculate the binary absorption coefficients of the individual lines of the O and S branches and of the quadrupole part of the Q branch. From these calculations and the experimental value of the total binary absorption coefficient of the fundamental band, the overlap part of the binary absorption coefficient of the Q branch was estimated.

THE PRESSURE-INDUCED ROTATIONAL ABSORPTION SPECTRUM OF HYDROGEN: I. A STUDY OF THE ABSORPTION INTENSITIES

1959 ◽  
Vol 37 (3) ◽  
pp. 362-376 ◽  
Author(s):  
Z. J. Kiss ◽  
H. P. Gush ◽  
H. L. Welsh
Keyword(s):  
Absorption Spectrum ◽  
Kinetic Energy ◽  
Infrared Spectrum ◽  
Absorption Coefficient ◽  
Quadrupole Interaction ◽  
Vibrational Band ◽  
Absorption Process ◽  
Relative Kinetic ◽  
Good Agreement ◽  
Gas Pressures

The pressure-induced infrared spectrum of H2 and mixtures of H2 with N2, He, Ne, A, Kr, and Xe was measured in the region 300–1400 cm−1 at total gas pressures up to 250 atm at 300° K and, where possible, at 195° K and 85° K. The spectrum shows greatly broadened S lines (ΔJ = + 2) with half widths which decrease as the temperature is lowered. The integrated absorption coefficient of the band is of the form [Formula: see text], where ρƒ is the density of the perturbing gas, except in the case of Xe for which a cubic term, [Formula: see text], is also necessary. The binary coefficient α1 increases by a factor of 28 in going from He to Xe. The theoretical band intensity, calculated on the basis of quadrupole interaction alone, is in good agreement with the experimental value only for Xe as perturbing gas; in other cases the calculated value is appreciably less than the observed value. The shape of the absorption contours suggests that the S lines are overlaid by a continuum increasing in intensity towards lower frequencies. This continuum is interpreted as the counterpart of the QR component in the vibrational band, that is, a collision-induced absorption due to overlap interaction in which the relative kinetic energy of the collision partners changes in the absorption process.

Dislocation structures around SiO2 Particles in aged Cu-Cr-SiO2

1978 ◽  
Vol 36 (1) ◽  
pp. 594-595
Author(s):  
N.J. Long ◽  
M.H. Loretto ◽  
C.H. Lloyd
Keyword(s):  
Flow Stress ◽  
Single Crystals ◽  
Room Temperature ◽  
Thin Foil ◽  
Age Hardening ◽  
Dispersion Strengthening ◽  
Accurate Picture ◽  
The Matrix ◽  
Very High ◽  
Good Agreement

IntroductionThere have been several t.e.m. studies (1,2,3,4) of the dislocation arrangements in the matrix and around the particles in dispersion strengthened single crystals deformed in single slip. Good agreement has been obtained in general between the observed structures and the various theories for the flow stress and work hardening of this class of alloy. There has been though some difficulty in obtaining an accurate picture of these arrangements in the case when the obstacles are large (of the order of several 1000's Å). This is due to both the physical loss of dislocations from the thin foil in its preparation and to rearrangement of the structure on unloading and standing at room temperature under the influence of the very high localised stresses in the vicinity of the particles (2,3).This contribution presents part of a study of the Cu-Cr-SiO2 system where age hardening from the Cu-Cr and dispersion strengthening from Cu-Sio2 is combined.

Molecule-Based Magnets—An Overview

MRS Bulletin ◽  
2000 ◽  
Vol 25 (11) ◽  
pp. 21-30 ◽  
Author(s):  
Joel S. Miller ◽  
Arthur J. Epstein
Keyword(s):  
Low Temperature ◽  
Vapor Deposition ◽  
Room Temperature ◽  
Chemical Vapor ◽  
Magnetic Ordering ◽  
Low Density ◽  
Materials Properties ◽  
The Common ◽  
New Processing ◽  
Very High

Molecule-based magnets are a broad, emerging class of magnetic materials that expand the materials properties typically associated with magnets to include low density, transparency, electrical insulation, and low-temperature fabrication, as well as combine magnetic ordering with other properties such as photoresponsiveness. Essentially all of the common magnetic phenomena associated with conventional transition-metal and rare-earth-based magnets can be found in molecule-based magnets. Although discovered less than two decades ago, magnets with ordering temperatures exceeding room temperature, very high (∼27.0 kOe or 2.16 MA/m) and very low (several Oe or less) coercivities, and substantial remanent and saturation magnetizations have been achieved. In addition, exotic phenomena including photoresponsiveness have been reported. The advent of molecule-based magnets offers new processing opportunities. For example, thin-film magnets can be prepared by means of low-temperature chemical vapor deposition and electrodeposition methods.

ION CHANNELING AND PIXE STUDIES OF S IMPLANTATION IN GaAs

1992 ◽  
Vol 02 (02) ◽  
pp. 151-159
Author(s):  
LIU SHIJIE ◽  
WANG JIANG ◽  
HU ZAOHUEI ◽  
XIA ZHONGHUONG ◽  
GAO ZHIGIANG ◽  
...  
Keyword(s):  
Room Temperature ◽  
Dislocation Loops ◽  
Good Recovery ◽  
Electrical Measurements ◽  
X Ray ◽  
Defect Complexes ◽  
Ion Channeling ◽  
Transmission Electron ◽  
Activation Efficiency ◽  
Very High

GaAs (100) crystals were implanted with 100 keV S+ to a dose of 3×1015 cm−2 in a nonchanneling direction at room temperature, and treated with rapid thermal annealing (RTA). He+ Rutherford backscattering and particle-induced X-ray emission in channeling mode in combination with transmission electron microscopy (TEM) were used to study the damage and the lattice location of S atoms. It is revealed that the RTA at 950 °C for 10 sec has resulted in a very good recovery of crystallinity with a few residual defects in the form of dislocation loops, and a very high substitutionality (~90%). The activation efficiency and the Hall mobility of the implanted samples are found to be low after the electrical measurements. Based on these results an extended dopant diffusion effect for the residual defects and a correlation between the electrical properties and defect complexes are suggested.

Very High Cycle Fatigue Behavior and Life Prediction of a Low Strength Weld Metal at Moderate Temperature

2011 ◽  
Author(s):  
Ming-Liang Zhu ◽  
Fu-Zhen Xuan ◽  
Zhengdong Wang
Keyword(s):  
Crack Initiation ◽  
Weld Metal ◽  
Room Temperature ◽  
Fatigue Behavior ◽  
Fatigue Properties ◽  
Dissimilar Welding ◽  
Initiation Mechanism ◽  
Metallic Inclusions ◽  
Low Strength ◽  
Very High

The fatigue properties of a low strength weld metal in a dissimilar welding joint in high cycle and very high cycle regimes were investigated by fully reversed axial tests in air at room temperature and 370°C. A clear duplex S-N curve existed as a result of the transition of fatigue failure mode from surface-induced failure to internal-induced failure at 370°C, while the S-N curve was continuously decreased at room temperature. A new model was successfully proposed to predict fatigue life, and interpret the crack initiation modes transition from surface inclusion to interior inclusion. It was concluded that cracks were initiated by competition among non-metallic inclusions, welding pores and discontinuous microstructures in high cycle regime. While in the very high cycle regime, non-metallic inclusions were the dominant crack initiation mechanism which depended on stress level, inclusion size as well as inclusion depth.

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