Anharmonicity and Hydrogen Bonding. The in-plane OH Bending and its Combination with the OH Stretching Vibration

1971 ◽  
Vol 49 (9) ◽  
pp. 1539-1544 ◽  
Author(s):  
M. Asselin ◽  
C. Sandorfy
Keyword(s):  
Hydrogen Bonding ◽  
The Other ◽  
Effect Of Temperature ◽  
Secondary Alcohols ◽  
Coupling Constant ◽  
Tertiary Alcohols ◽  
Anharmonicity Constant ◽  
Stretching Vibration ◽  
The One ◽  
Anharmonic Coupling

The infrared spectra of isopropanol, tert-butanol, and their deuterated homologues were measured between 1600 and 1160 cm−1 in a mixture of CCl3F and methylcyclohexane-d14 at temperatures ranging from 20 to −182 °C. The assignments of the in-plane OH deformation (δOH) bands of alcohols are confirmed by these low temperature measurements. An explanation is proposed for the great apparent differences between the δOH frequencies of primary and secondary alcohols on the one hand, and tertiary alcohols on the other. The effect of temperature on the δOH frequency of hydrogen bonded alcohols is found to be slight. Hydrogen bonding increases significantly the anharmonic coupling constant between νOH and δOH It remains, however, much smaller than the anharmonicity constant of νOH itself.

The effect of cation concentration on the nitrogen splitting constant of nitroxide free radicals

1990 ◽  
Vol 55 (10) ◽  
pp. 2377-2380
Author(s):  
Hamza A. Hussain
Keyword(s):  
Hydrogen Peroxide ◽  
Hydrogen Bonding ◽  
Free Radicals ◽  
Esr Spectroscopy ◽  
The Other ◽  
Tetraethylammonium Bromide ◽  
Splitting Constant ◽  
The One ◽  
Positively Charged ◽  
Two Equilibria

Nitroxide free radicals prepared from diethylamine, piperidine and pyrrolidine by oxidation with hydrogen peroxide were studied by ESR spectroscopy. The changes in the 14N splitting constant (aN) caused by the addition of KBr or tetraethylammonium bromide were measured in dependence on the concentration of the ions. For diethylamine nitroxide and piperidine nitroxide, the results are discussed in terms of two equilibria: the one, involving the anion, is associated with a gain or loss of hydrogen bonds to the nitroxide oxygen atom, the other is associated with the formation of solvent shared units involving the cation, which results in changes in the hydrogen bonding strenght. The large increase in the aN value in the case of pyrrolidine nitroxide is explained in terms of an interaction from one side of the positively charged N atom; the increase in aN in the case of diethylamine and piperidine nitroxides is explained in terms of interactions with both sides of the positively charged N atom.

scholarly journals STABILITY OF GROUND STATES IN SECTORS AND ITS APPLICATION TO THE WIGNER–WEISSKOPF MODEL

2001 ◽  
Vol 13 (04) ◽  
pp. 513-528 ◽  
Author(s):  
ASAO ARAI ◽  
MASAO HIROKAWA
Keyword(s):  
Excited State ◽  
Scalar Field ◽  
Ground State ◽  
Adjoint Operator ◽  
Ground States ◽  
The Other ◽  
Coupling Constant ◽  
A Value ◽  
First Excited State ◽  
The One

We consider two kinds of stability (under a perturbation) of the ground state of a self-adjoint operator: the one is concerned with the sector to which the ground state belongs and the other is about the uniqueness of the ground state. As an application to the Wigner–Weisskopf model which describes one mode fermion coupled to a quantum scalar field, we prove in the massive case the following: (a) For a value of the coupling constant, the Wigner–Weisskopf model has degenerate ground states; (b) for a value of the coupling constant, the Wigner–Weisskopf model has a first excited state with energy level below the bottom of the essential spectrum. These phenomena are nonperturbative.

A Molecular Basis for Indiscriminate and Selective Cell Adhesion

1969 ◽  
Vol 4 (3) ◽  
pp. 799-813
Author(s):  
B. M. JONES ◽  
G. A. MORRISON
Keyword(s):  
Molecular Basis ◽  
Liver Cells ◽  
The Other ◽  
Effect Of Temperature ◽  
Fibroblast Cells ◽  
Kcal Mole ◽  
Turbidimetric Method ◽  
Mixed Aggregates ◽  
The One ◽  
Basic Similarity

When cells of different type are intermixed they will adhere to one another indiscriminately. In mixed aggregates of 9th-incubation-day fibroblasts and 12th-day liver cells from chick embryos, the liver cells accumulated as groups which moved at random relative to the surrounding fibroblasts; groups of liver cells were liable to migrate from the interior to occupy the surface. Quantitative estimations of the effect of temperature on the rate of reaggregation of dissociated fibroblast cells, using a turbidimetric method, indicated that the rate was controlled by a chemical reaction. The energy of activation calculated for this reaction was 21.1.kcal/mole. The significance of this value is discussed in relation to values associated with other kinds of reactions. The indiscriminate adhesions formed between the unlike cells allowed them to move relative to one another, whereas the adhesions (selective) formed between like cells, when by chance they made contact, did not. Thus the aggregates of like cells increased in extent and the inherent ability of homogeneous aggregates to consolidate the intercellular bonding ensured that the process became effectively irreversible. If, as is evident, there is a basic similarity in the adhesive mechanisms of the various types of cells that exist, the question that required answering was what kind of differences could occur in the bonds to account for differential adhesiveness upon which the sorting out process depends. It is suggested that the linkage sites at the surfaces of cells move (oscillate) between two positions, the one unfavourable and the other favourable to adhesion, and the theory put forward is that differential adhesiveness is the expression of differences in the frequency of the oscillations of the otherwise equivalent linkage sites. The theory provides an explanation for the temporary nature of indiscriminate adhesion allowing the movement of unlike cells in contact relative to one another and the more permanent nature of selective adhesions responsible for the consolidation of like cells in their appointed territories.

scholarly journals Assessment of the Moisture Effect on Gaseous Products of Self-Heating of Wood Chips

2017 ◽  
Vol 12 (2) ◽  
pp. 52-60 ◽  
Author(s):  
Hana Věžníková ◽  
Michaela Perďochová ◽  
Martina Uhrová
Keyword(s):  
The Other ◽  
Wood Chips ◽  
Effect Of Temperature ◽  
Gas Release ◽  
Oxidation Reactions ◽  
Moisture Effect ◽  
Gaseous Products ◽  
Self Heating ◽  
The One ◽  
Increasing Temperature

Abstract Biofuels are stored in large quantities and may be susceptible to self-ignition. The possible methods of indication of temperature increase include the analysis of the gaseous products of heating where concentrations of certain gases may increase with increasing temperature. Gas release is also affected by the moisture of the material given that the moisture level changes surface accessibility for oxygen on the one side and serves as a catalyst of the oxidation reactions on the other. The present project analysed the effect of temperature and moisture on gaseous products of heating of wood chips, one of frequently used biofuels, with the aim to determine a suitable gaseous indicator of beginning self-ignition.

scholarly journals NONPERTURBATIVE DISPERSIVE SECTOR IN STRONG (QUASI-)ABELIAN FIELDS

2001 ◽  
Vol 16 (01) ◽  
pp. 57-82
Author(s):  
G. CVETIČ ◽  
JI-YOUNG YU
Keyword(s):  
Energy Density ◽  
Lagrangian Density ◽  
Absorptive Part ◽  
Pair Creation ◽  
The Other ◽  
Coupling Constant ◽  
Effective Lagrangian ◽  
Abelian Fields ◽  
The One ◽  
Dispersive Part

In strong (quasi-)Abelian fields, even at the one-loop level of the coupling constant, quantum fluctuations of fermions induce an effective Lagrangian density whose imaginary (absorptive) part is purely nonperturbative and known to be responsible for the fermion–antifermion pair creation. On the other hand, the induced real (dispersive) part has perturbative and nonperturbative contributions. In the one-loop case, we argue how to separate the two contributions from each other for any strength of the field. We show numerically that the nonperturbative contributions are in general comparable with or larger than the induced perturbative ones. We arrive at qualitatively similar conclusions also for the induced energy density. Further, we investigate numerically the quasianalytic continuation of the perturbative results into the nonperturbative sector, by employing (modified) Borel–Padé. It turns out that in the case at hand, we have to integrate over renormalon singularities, but there is no renormalon ambiguity involved.

scholarly journals The Effect of Temperature Gradients on the Exhalation Rate of Radon Generated by Building Materials

2019 ◽  
Vol 10 (1) ◽  
pp. 21-24
Author(s):  
Marius-Lucian Botoș ◽  
Zsombor Kisfaludi-Bak
Keyword(s):  
Indoor Air Quality ◽  
Indoor Air ◽  
Building Materials ◽  
Temperature Gradients ◽  
The Other ◽  
Effect Of Temperature ◽  
Exhalation Rate ◽  
Radon Exhalation ◽  
Soil Walls ◽  
The One

Abstract There is increasing interest in indoor air quality studies. The effect of exhaled radon from soil, walls and ceilings has well-known consequences on human health, so the importance of modelling has been established. The present paper examines radon exhalation, on the one hand, only in the case of diffusion and, on the other hand, diffusion and advection. Comparing the results of the two test types, we can determine how significant the effect of temperature gradients on radon exhalation is. For a broader investigation, we performed the parametric tests on several types of material, wall thickness and radon concentration.

A Low Temperature Infrared Study of Hydrogen Bonding in N-Alkylacetamides

1973 ◽  
Vol 51 (21) ◽  
pp. 3640-3646 ◽  
Author(s):  
Marie-Claude Bernard-Houplain ◽  
C. Sandorfy
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Low Temperature ◽  
Infrared Spectra ◽  
Bond Formation ◽  
Coupling Constant ◽  
Infrared Study ◽  
Hydrogen Bond Formation ◽  
Stretching Vibration ◽  
Secondary Amides

The infrared spectra of N-methylacetamide and two other secondary amides were measured in solution at temperatures ranging from 22 to −190 °C in both the fundamental and the overtone regions. At least two hydrogen bonded species are found as association increases with decreasing temperature. The effect of hydrogen bond formation on the anharmonicity of the NH stretching vibration and on the NH stretching – NH bending coupling constant is examined.

Note on Selection of Coordinate Systems for Geodynamics

1975 ◽  
Vol 26 ◽  
pp. 395-407
Author(s):  
S. Henriksen
Keyword(s):  
Sea Level ◽  
The Other ◽  
Coordinate Systems ◽  
Mean Sea Level ◽  
The Earth ◽  
The One ◽  
Static Systems ◽  
Selection Of

The first question to be answered, in seeking coordinate systems for geodynamics, is: what is geodynamics? The answer is, of course, that geodynamics is that part of geophysics which is concerned with movements of the Earth, as opposed to geostatics which is the physics of the stationary Earth. But as far as we know, there is no stationary Earth – epur sic monere. So geodynamics is actually coextensive with geophysics, and coordinate systems suitable for the one should be suitable for the other. At the present time, there are not many coordinate systems, if any, that can be identified with a static Earth. Certainly the only coordinate of aeronomic (atmospheric) interest is the height, and this is usually either as geodynamic height or as pressure. In oceanology, the most important coordinate is depth, and this, like heights in the atmosphere, is expressed as metric depth from mean sea level, as geodynamic depth, or as pressure. Only for the earth do we find “static” systems in use, ana even here there is real question as to whether the systems are dynamic or static. So it would seem that our answer to the question, of what kind, of coordinate systems are we seeking, must be that we are looking for the same systems as are used in geophysics, and these systems are dynamic in nature already – that is, their definition involvestime.

Nucleation of Disorder in Fe3Al Alloys

1967 ◽  
Vol 25 ◽  
pp. 312-313
Author(s):  
P. R. Swann ◽  
W. R. Duff ◽  
R. M. Fisher
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Annealing Temperature ◽  
Antiphase Domain ◽  
Effect Of Temperature ◽  
Domain Structures ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
Higher Temperature ◽  
The One

Recently we have investigated the phase equilibria and antiphase domain structures of Fe-Al alloys containing from 18 to 50 at.% Al by transmission electron microscopy and Mössbauer techniques. This study has revealed that none of the published phase diagrams are correct, although the one proposed by Rimlinger agrees most closely with our results to be published separately. In this paper observations by transmission electron microscopy relating to the nucleation of disorder in Fe-24% Al will be described. Figure 1 shows the structure after heating this alloy to 776.6°C and quenching. The white areas are B2 micro-domains corresponding to regions of disorder which form at the annealing temperature and re-order during the quench. By examining specimens heated in a temperature gradient of 2°C/cm it is possible to determine the effect of temperature on the disordering reaction very precisely. It was found that disorder begins at existing antiphase domain boundaries but that at a slightly higher temperature (1°C) it also occurs by homogeneous nucleation within the domains. A small (∼ .01°C) further increase in temperature caused these micro-domains to completely fill the specimen.

Stories and the Self

2020 ◽  
Vol 32 (2) ◽  
pp. 47-58 ◽  
Author(s):  
Stefan Krause ◽  
Markus Appel
Keyword(s):  
Meta Analysis ◽  
The Self ◽  
The Other ◽  
Lower Degree ◽  
Contrast Effects ◽  
Self Perception ◽  
Self Perceptions ◽  
Other Hand ◽  
The One ◽  
Implicit And Explicit

Abstract. Two experiments examined the influence of stories on recipients’ self-perceptions. Extending prior theory and research, our focus was on assimilation effects (i.e., changes in self-perception in line with a protagonist’s traits) as well as on contrast effects (i.e., changes in self-perception in contrast to a protagonist’s traits). In Experiment 1 ( N = 113), implicit and explicit conscientiousness were assessed after participants read a story about either a diligent or a negligent student. Moderation analyses showed that highly transported participants and participants with lower counterarguing scores assimilate the depicted traits of a story protagonist, as indicated by explicit, self-reported conscientiousness ratings. Participants, who were more critical toward a story (i.e., higher counterarguing) and with a lower degree of transportation, showed contrast effects. In Experiment 2 ( N = 103), we manipulated transportation and counterarguing, but we could not identify an effect on participants’ self-ascribed level of conscientiousness. A mini meta-analysis across both experiments revealed significant positive overall associations between transportation and counterarguing on the one hand and story-consistent self-reported conscientiousness on the other hand.

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