scholarly journals Temperature effects on the C–H symmetric stretching vibrational frequencies of guest hydrocarbon molecules in 512, 51262 and 51264 cages of sI and sII clathrate hydrates

RSC Advances ◽  
2020 ◽  
Vol 10 (61) ◽  
pp. 37582-37587
Author(s):  
Go Fuseya ◽  
Satoshi Takeya ◽  
Akihiro Hachikubo
Keyword(s):  
Temperature Effects ◽  
Vibrational Frequencies ◽  
Clathrate Hydrates ◽  
Hydrocarbon Molecules

Temperature effects on the C–H symmetric stretch of hydrocarbons in various cages of sI and sII clathrate hydrates were observed.

scholarly journals Retracted Article: Effect of temperature and large guest molecules on the C–H symmetric stretching vibrational frequencies of methane in structure H and I clathrate hydrates

RSC Advances ◽  
2018 ◽  
Vol 8 (6) ◽  
pp. 3237-3242 ◽  
Author(s):  
Go Fuseya ◽  
Satoshi Takeya ◽  
Akihiro Hachikubo
Keyword(s):  
Temperature Effects ◽  
Vibrational Frequencies ◽  
Clathrate Hydrates ◽  
Effect Of Temperature ◽  
Guest Molecules ◽  
Retracted Article

Temperature effects on C–H symmetric stretching frequencies of CH4 in water cages of sI and sH clathrate hydrates were clarified.

scholarly journals Effect of temperature and large guest molecules on the C–H symmetric stretching vibrational frequencies of methane in structure H and I clathrate hydrates

RSC Advances ◽  
2020 ◽  
Vol 10 (30) ◽  
pp. 17473-17478
Author(s):  
Go Fuseya ◽  
Satoshi Takeya ◽  
Akihiro Hachikubo
Keyword(s):  
Temperature Effect ◽  
Vibrational Frequencies ◽  
Clathrate Hydrates ◽  
Effect Of Temperature ◽  
Guest Molecules

Temperature effect on C–H symmetric stretching frequencies of CH4 in water cages of sI and sH clathrate hydrates were clarified.

scholarly journals Retraction: Effect of temperature and large guest molecules on the C–H symmetric stretching vibrational frequencies of methane in structure H and I clathrate hydrates

RSC Advances ◽  
2020 ◽  
Vol 10 (29) ◽  
pp. 16904-16904
Author(s):  
Go Fuseya ◽  
Satoshi Takeya ◽  
Akihiro Hachikubo
Keyword(s):  
Vibrational Frequencies ◽  
Clathrate Hydrates ◽  
Effect Of Temperature ◽  
Guest Molecules

Retraction of ‘Effect of temperature and large guest molecules on the C–H symmetric stretching vibrational frequencies of methane in structure H and I clathrate hydrates’ by Akihiro Hachikubo et al., RSC Adv., 2018, 8, 3237–3242, DOI: 10.1039/c7ra12334e.

Density and temperature effects on electron mobilities in gaseous, critical and liquid n-hexane, cyclohexane, and cyclopentane

1978 ◽  
Vol 56 (18) ◽  
pp. 2388-2395 ◽  
Author(s):  
Sam S. -S. Huang ◽  
Gordon R. Freeman
Keyword(s):  
Temperature Effects ◽  
Low Frequency ◽  
Inelastic Collisions ◽  
Negative Ion ◽  
Minimum Size ◽  
Molecular Cluster ◽  
Low Density ◽  
Temperature Coefficients ◽  
Temperature Dependences ◽  
Hydrocarbon Molecules

In the low density vapors the density normalized mobilities μn of thermal electrons decreased in the order n-hexane > cyclopentane > cyclohexane, although the differences were only ∼ 10%. The mobilities began to increase at electric field strengths E/n > 0.4 Td in cyclopentane, > 0.5 Td in cyclohexane and remained independent of field strength up to 1.5 Td in n-hexane. The ratio of the threshold drift velocity for electron heating to the speed of low frequency sound in the gas, υd(threshold)/c0 = 11 in cyclopentane, 14 in cyclohexane, and is > 35 in n-hexane; it increases with decreasing sphericity of the molecules. The electrons are cooled mainly by inelastic collisions with the hydrocarbon molecules. The temperature coefficients of mobilities in the low density gases increase as the molecules become more globular, which could reflect the participation of either low lying transient negative ion states or a Ramsauer–Townsend effect in the scattering processes. The normalized mobilities μn in the saturated vapors began to decrease at n = 4 × 1019 molecules/cm3 in n-hexane, 13 × 1019 in cyclohexane, and 30 × 1019 in cyclopentane. It appears that the minimum size of molecular cluster required for electron quasilocalization is smaller in n-hexane than in cyclohexane, and larger in cyclopentane. Electron localization interactions are weaker for more globular molecules.Mobilities in the critical fluids were 16 cm2/V s in n-hexane, 23 in cyclohexane, and 22 in cyclopentane.Mobilities in the liquids were independent of field up to the highest value used, which was 1.5 Td in the hexanes and 0.9 Td in cyclopentane. The mobilities and their temperature dependences were interpreted in terms of a model.

An Attack on the Contamination Problem in the Electron Microscope

1967 ◽  
Vol 25 ◽  
pp. 368-368
Author(s):  
J. J. Kelsch ◽  
A. Holtz
Keyword(s):  
Electron Microscope ◽  
Pressure Gradient ◽  
Ionization Potential ◽  
Simple Solution ◽  
Specimen Surface ◽  
Contamination Rate ◽  
Local Pressure ◽  
High Ionization ◽  
Hydrocarbon Molecules ◽  
Contamination Problem

A simple solution to the serious problem of specimen contamination in the electron microscope is presented. This is accomplished by the introduction of clean helium into the vacuum exactly at the specimen position. The local pressure gradient thus established inhibits the migration of hydrocarbon molecules to the specimen surface. The high ionization potential of He permits the use of relatively large volumes of the gas, without interfering with gun stability. The contamination rate is reduced on metal samples by a factor of 10.

New replica method with plasma polymerized film by glow discharge

1988 ◽  
Vol 46 ◽  
pp. 414-415
Author(s):  
A. Tanaka ◽  
M. Yamaguchi ◽  
T. Hirano
Keyword(s):  
Power Supply ◽  
Plasma Polymerization ◽  
Vacuum Chamber ◽  
Complex Surface ◽  
Replica Method ◽  
Metal Extraction ◽  
High Voltage Power Supply ◽  
Negative Glow ◽  
Hydrocarbon Gas ◽  
Hydrocarbon Molecules

The plasma polymerization replica method and its apparatus have been devised by Tanaka (1-3). We have published several reports on its application: surface replicas of biological and inorganic specimens, replicas of freeze-fractured tissues and metal-extraction replicas with immunocytochemical markers.The apparatus for plasma polymerization consists of a high voltage power supply, a vacuum chamber containing a hydrocarbon gas (naphthalene, methane, ethylene), and electrodes of an anode disk and a cathode of the specimen base. The surface replication by plasma polymerization in negative glow phase on the cathode was carried out by gassing at 0.05-0.1 Torr and glow discharging at 1.5-3 kV D.C. Ionized hydrocarbon molecules diffused into complex surface configurations and deposited as a three-dimensionally polymerized film of 1050 nm in thickness.The resulting film on the complex surface had uniform thickness and showed no granular texture. Since the film was chemically inert, resistant to heat and mecanically strong, it could be treated with almost any organic or inorganic solvents.

Reduction of Specimen Contamination in Electron-Beam Instruments

1976 ◽  
Vol 34 ◽  
pp. 576-577
Author(s):  
G. Lehmpfuhl ◽  
P. J. Smith
Keyword(s):  
Electron Beam ◽  
Cold Trap ◽  
Beam Diameter ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Hydrocarbon Molecules ◽  
Electron Microscopes ◽  
Combination Of Methods ◽  
Convergent Beam ◽  
Very High

Specimens being observed with electron-beam instruments are subject to contamination, which is due to polymerization of hydrocarbon molecules by the beam. This effect becomes more important as the size of the beam is reduced. In convergent-beam studies with a beam diameter of 100 Å, contamination was observed to grow on samples at very high rates. Within a few seconds needles began forming under the beam on both the top and the underside of the sample, at growth rates of 400-500 Å/s, severely limiting the time available for observation. Such contamination could cause serious difficulty in examining a sample with the new scanning transmission electron microscopes, in which the beam is focused to a few angstroms.We have been able to reduce the rate of contamination buildup by a combination of methods: placing an anticontamination cold trap in the sample region, preheating the sample before observation, and irradiating the sample with a large beam before observing it with a small beam.

Characterization of carbides in M50NiL

1991 ◽  
Vol 49 ◽  
pp. 606-607
Author(s):  
L. S. Lin ◽  
K. P. Gumz ◽  
A. V. Karg ◽  
C. C. Law
Keyword(s):  
Temperature Effects ◽  
Base Composition ◽  
Lattice Parameter ◽  
Control Surface ◽  
Carbide Formation ◽  
Particle Sizes ◽  
Low Carbon ◽  
Fee Structure ◽  
Heat Treated

Carbon and temperature effects on carbide formation in the carburized zone of M50NiL are of great importance because they can be used to control surface properties of bearings. A series of homogeneous alloys (with M50NiL as base composition) containing various levels of carbon in the range of 0.15% to 1.5% (in wt.%) and heat treated at temperatures between 650°C to 1100°C were selected for characterizations. Eleven samples were chosen for carbide characterization and chemical analysis and their identifications are listed in Table 1.Five different carbides consisting of M6C, M2C, M7C3 and M23C6 were found in all eleven samples examined as shown in Table 1. M6C carbides (with least carbon) were found to be the major carbide in low carbon alloys (<0.3% C) and their amounts decreased as the carbon content increased. In sample C (0.3% C), most particles (95%) encountered were M6C carbide with a particle sizes range between 0.05 to 0.25 um. The M6C carbide are enriched in both Mo and Fe and have a fee structure with lattice parameter a=1.105 nm (Figure 1).

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