Collision-induced microwave absorption in Ne–Xe and Ar–Xe gaseous mixtures at 2.3 cm−1

1978 ◽  
Vol 56 (12) ◽  
pp. 1559-1564 ◽  
Author(s):  
I. R. Dagg ◽  
G. E. Reesor ◽  
M. Wong
Keyword(s):  
Absorption Coefficient ◽  
Microwave Absorption ◽  
Line Shape ◽  
Shape Factor ◽  
Room Temperature ◽  
Inert Gas ◽  
Interference Effects ◽  
Many Body ◽  
Gaseous Mixtures ◽  
Density Ratios

Collision-induced microwave absorption has been observed at 2.3 cm−1 for the inert gas mixtures Ne–Xe and Ar–Xe. The absorption coefficient has been measured at room temperature for a range of density products up to 15 000 amagat2 for different density ratios. The present results are compared with the results obtained earlier at 4.4 cm−1. The intracollisional absorption coefficient arising from two body interactions is approximately proportional to the square of the frequency for both mixtures. The intercollisional interference effects have led to a larger suppression of the absorption than was observed previously at 4.4 cm−1. An expression for the intercollisional line shape factor was used to fit the data. At high densities, there is observed a marked increase in the absorption which has also been observed at 4.4 cm−1 and which may be attributed to many body collisions.

Collision-induced microwave absorption in Ne–Xe and Ar–Xe gaseous mixtures

1978 ◽  
Vol 56 (8) ◽  
pp. 1046-1053 ◽  
Author(s):  
I. R. Dagg ◽  
G. E. Reesor ◽  
M. Wong
Keyword(s):  
Absorption Coefficient ◽  
Microwave Absorption ◽  
Low Frequency ◽  
Exponential Model ◽  
Many Body ◽  
Dipole Strength ◽  
Gaseous Mixtures ◽  
A Value ◽  
Induced Dipole ◽  
Density Ratios

Collision-induced microwave absorption has been observed at 4.4 cm−1 for the inert gas mixtures Ne–Xe and Ar–Xe. The absorption coefficient has been measured at room temperature for a range of density products up to 15 000 amagat2 and for different density ratios. The intracollisional absorption coefficient has been determined at this low frequency for each mixture from the data at low densities. These results for the absorption coefficient along with existing infrared results have yielded an accurate value for the zeroth moment for each of the spectra and hence improved values for the induced dipole moment parameters for the exponential model. For the range parameter, ρ, we obtain values of 0.312 Å and 0.408 Å, respectively, for the Ne–Xe and Ar–Xe mixtures. The values for the dipole strength parameters, μσ, calculated using the Lennard-Jones (12-6) potential are 0.0293 and 0.0328 D, respectively. Evaluations of μσ have also been carried out using other potentials. In particular, for Ne–Xe a value of μσ = 0.0377 D is calculated using the more realistic Morse – Spine – van der Waals (MSV) potential. At higher densities the results reveal intercollisional interference effects which result in a reduction of the absorption. The amount of reduction depends on the ratios of the gases in the mixture. In the highest density range studied, there is observed a marked increase in the absorption which may be attributed to many-body collisions.

Collision-induced microwave absorption in gaseous mixtures of various rare gases at 2.3 cm−1

1980 ◽  
Vol 58 (5) ◽  
pp. 633-641 ◽  
Author(s):  
I. R. Dagg ◽  
W. D. Leckie ◽  
L. A. A. Read
Keyword(s):  
Microwave Absorption ◽  
Room Temperature ◽  
Infrared Region ◽  
Exponential Model ◽  
Rare Gas ◽  
Rare Gases ◽  
Gaseous Mixtures ◽  
Induced Dipole ◽  
Upper Limits ◽  
Density Ratios

Collision-induced microwave absorption has been observed at 2.3 cm−1 for the rare gas mixtures Ne–Kr, Ar–Kr, Ar–Xe, and Kr–Xe. The absorption coefficient has been measured at room temperature for density products up to 8000 amagat2 and for various density ratios. These results have been used in conjunction with those of the infrared region to determine more accurately the zeroth moment for each of the spectra and hence have allowed improved values for the induced dipole moment parameters for the exponential model. Upper limits to the absorption in He–Xe and He–Ar mixtures in the microwave region have also been established.

scholarly journals Few Body Effects in the Electron and Positron Impact Ionization of Atoms

Atoms ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 33
Author(s):  
R.I. Campeanu ◽  
Colm T. Whelan
Keyword(s):  
Electron Impact ◽  
Cross Sections ◽  
Differential Cross ◽  
Impact Ionization ◽  
Inert Gas ◽  
Interference Effects ◽  
Positron Impact ◽  
Competing Interactions ◽  
Energy Sharing

Triple differential cross sections (TDCS) are presented for the electron and positron impact ionization of inert gas atoms in a range of energy sharing geometries where a number of significant few body effects compete to define the shape of the TDCS. Using both positrons and electrons as projectiles has opened up the possibility of performing complementary studies which could effectively isolate competing interactions that cannot be separately detected in an experiment with a single projectile. Results will be presented in kinematics where the electron impact ionization appears to be well understood and using the same kinematics positron cross sections will be presented. The kinematics are then varied in order to focus on the role of distortion, post collision interaction (pci), and interference effects.

Preparing high purity λ-Ti3O5 and Li/λ-Ti3O5 as a high performance electromagnetic wave absorber

2021 ◽  
Author(s):  
xiankai fu ◽  
Wanqi Chen ◽  
Xiaowen Hao ◽  
Zhimin Zhang ◽  
Ruolan Tang ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
Microwave Absorption ◽  
High Purity ◽  
High Performance ◽  
Room Temperature

This paper reports a new candidate material λ-Ti3O5 for microwave absorption. λ-Ti3O5 has been proposed to be metastable and has emerged at room temperature only in the form of nanocrystals....

Effects of acetone in heparin on the multiple inert gas elimination technique

1985 ◽  
Vol 58 (4) ◽  
pp. 1143-1147 ◽  
Author(s):  
F. L. Powell ◽  
F. A. Lopez ◽  
P. D. Wagner
Keyword(s):  
Partial Pressure ◽  
Dead Space ◽  
Room Temperature ◽  
Inert Gas ◽  
Published Data ◽  
Physiological Mechanisms ◽  
Heparinized Saline ◽  
Partial Pressures ◽  
Ventilation Perfusion Ratio ◽  
Mixed Venous

We have detected acetone in several brands of heparin. If uncorrected, this leads to errors in measuring acetone in blood collected in heparinized syringes, as in the multiple inert gas elimination technique for measuring ventilation-perfusion ratio (VA/Q) distributions. Error for acetone retention [R = arterial partial pressure-to-mixed venous partial pressure (P-V) ratio] is usually small, because R is normally near 1.0, and the error is similar in arterial and mixed venous samples. However, acetone excretion [E = mixed expired partial pressure (P-E)-to-P-V ratio] will appear erroneously low, because P-E is accurately measured in dry syringes, but P-V is overestimated. A physical model of a homogeneous alveolar lung at room temperature and without dead space shows: the magnitude of acetone E error depends upon the ratio of blood sample to heparinized saline volumes and acetone partial pressures, without correction, acetone E can be less than that of less soluble gases like ether, a situation incompatible with conventional gas exchange theory, and acetone R and E can be correctly calculated using the principle of mass balance if the acetone partial pressure in heparinized saline is known. Published data from multiple inert gas elimination experiments with acetone-free heparin, in our labs and others, are within the limits of experimental error. Thus the hypothesis that acetone E is anomalously low because of physiological mechanisms involving dead space tissue capacitance for acetone remains to be tested.

scholarly journals Synthesis and Characterisation of Thin Films of Bismuth Triiodide for Semiconductor Radiation Detectors

2014 ◽  
Vol 2014 ◽  
pp. 1-3 ◽  
Author(s):  
Alka Garg ◽  
Monika Tomar ◽  
Vinay Gupta
Keyword(s):  
Thin Films ◽  
Absorption Coefficient ◽  
Room Temperature ◽  
Active Material ◽  
Visible Region ◽  
Radiation Detectors ◽  
Radiation Absorption ◽  
X Rays ◽  
X Ray ◽  
Bismuth Iodide

Bismuth iodide is a potentially active material for room temperature radiation detector, as it is well reported in the literature that it has both wide energy band gap and high atomic absorption coefficient. Crystalline films of high atomic number and high radiation absorption coefficient can absorb the X-rays and convert them directly into electrical charges which can be read by imaging devices. Therefore, it was proposed to grow thin films of Bismuth iodide on glass substrate using thermal evaporation technique in vacuum to avoid the inclusion of impurities in the films. The structural studies of the films were carried out using XRD and optical absorption measurement was carried out in the UV/VIS region using spectrophotometer. All Bismuth iodide films grown at room temperature are polycrystalline and show X-ray diffraction peaks at angles reported in research papers. The optical transmission spectra of BiI3 films show a high transmission of about 80% in visible region with a sharp fall near the fundamental absorption at 650 nm. Resistivity of the as-grown film was found to be around 1012 ohm-cm suitable value for X-ray detection application. Films were subjected to scanning electron microscopy to study the growth features of both as-grown and annealed films.

Reversible Changes in the Electronic and Optical Properties of Micro-Crystalline ln2O 3-x: A Comparison with Amorphous In2O3-x

1996 ◽  
Vol 426 ◽  
Author(s):  
B. Pashmakov ◽  
H. Fritzsche ◽  
B. Claflin
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Absorption Coefficient ◽  
Ultraviolet Light ◽  
Indium Oxide ◽  
Electrical Conductance ◽  
Inert Gas ◽  
Optical Absorption Coefficient ◽  
Electronic And Optical Properties

AbstractThe electrical conductance and optical absorption coefficient of microcrystalline indium oxide (c – In2 O 3-x ) can be changed reversibly by several orders of magnitude by photoreduction and reoxidation. Photoreduction is achieved by exposure to ultraviolet light hv ≥ 3.5eV in vacuum or an inert gas. The effects are similar to those previously observed in amorphous In2 O3-x

EFFECTIVE MAGNETIC ANISOTROPY AND COERCIVITY IN Fe NANOPARTICLES PREPARED BY INERT GAS CONDENSATION

2006 ◽  
Vol 20 (01) ◽  
pp. 37-47
Author(s):  
LUBNA RAFIQ SHAH ◽  
BAKHTYAR ALI ◽  
S. K. HASANAIN ◽  
A. MUMTAZ ◽  
C. BAKER ◽  
...  
Keyword(s):  
Room Temperature ◽  
Size Range ◽  
Magnetic Measurements ◽  
Uniaxial Anisotropy ◽  
Inert Gas ◽  
Condensation Process ◽  
Gas Condensation ◽  
Inert Gas Condensation ◽  
Fe Nanoparticles ◽  
Characterization Studies

We present magnetic measurements on iron ( Fe ) nanoparticles in the size range 10–30 nm produced by the Inert Gas Condensation process (IGC). Structural characterization studies show the presence of a core/shell structure, where the core is bcc Fe while the surface layer is Fe -oxide. Analysis of the magnetic measurements shows that the nanoparticles display very large uniaxial anisotropy, K eff ≈3 - 4 × 106 erg/cc. The observed room temperature coercivities lie in the range ≈600 – 973 Oe , much larger than those expected from the Stoner–Wohlfarth model using the bulk iron anisotropy. It can be inferred from the coercivity variation with the particle size that there is a general trend of the coercivity increasing with size, culminating finally in a decrease for high sizes (30 nm) possibly due to the onset of non-coherent magnetization reversal processes.

Interference effects in the spectrum of HD: IV: the pure rotational band at room temperature

1986 ◽  
Vol 64 (3) ◽  
pp. 227-231 ◽  
Author(s):  
A. R. W. McKellar
Keyword(s):  
Spectral Resolution ◽  
Rotational Band ◽  
Path Length ◽  
Room Temperature ◽  
Dipole Transition ◽  
Rotational Spectrum ◽  
Density Range ◽  
Interference Effects ◽  
Fundamental Band ◽  
Line Strengths

The rotational spectrum of HD has been studied in absorption at room temperature for a density range of 6–57 amagat. Spectra were obtained in the 170- to 360-cm−1 region, including the R0(1), R0(2), and R0(3) transitions, with a 1-m path length and a spectral resolution varying from 0.05 to 0.20 cm−1. The observed line strengths were used to determine values for the dipole transition moments of HD in the range of 7.4 to 7.8 × 10−4 D, which is somewhat lower than currently accepted theoretical values of about 8.3–8.4 × 10−4 D. Only very small effects (≈0.2% per amagat) were found due to collisional interference on the line strengths; this result contrasts with much larger interference effects observed in the fundamental band, and it also casts some doubt on other recent studies of the rotational spectrum where larger interference effects were reported.

scholarly journals Forming pressure effect on microstructure and mechanical properties of nanocrystalline aluminum synthesized by inert gas condensation

2019 ◽  
Vol 79 ◽  
pp. 02002
Author(s):  
Shangshu Wu ◽  
Zhou Yu ◽  
Junjie Wang ◽  
Hanxin Zhang ◽  
Chaoqun Pei ◽  
...  
Keyword(s):  
Room Temperature ◽  
High Vacuum ◽  
Inert Gas ◽  
Helium Atmosphere ◽  
Gas Condensation ◽  
Inert Gas Condensation ◽  
In Situ Forming ◽  
Nanocrystalline Aluminum ◽  
Al Powder

The preparation of nanocrystalline aluminum (NC Al) was conducted in two steps. After the NC Al powder was synthesized by an Inert gas condensation (IGC) method in a helium atmosphere of 500 Pa, the NC Al powder was in-situ compacted into a pellet with a 10 mm diameter and 250 μm-300 μm thickness in a high vacuum (10-6 Pa-10-7 Pa) at room temperature. The NC Al samples were not exposed to air during the entire process. After the pressure reached 6 GPa, the relative density could reach 99.83%. The results showed that the grain size decreased with the increased of in-situ forming pressure. The NC Al samples present obvious ductile fracture, and the tensile properties were greatly changed with the increase of forming pressure.

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