摘要:

The contributions of the M++and (M - Het·)+ions in the mass spectra of bipyridyl and biquinolyl derivatives have been determined. Studies were also made of triply charged molecular ions and of the mass spectrum of 8,8′-biquinolyl.

ISSN:0038-7010    

DOI:10.1080/00387017708065012

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Infrared and Raman spectroscopy has been widely used at last decade to elucidate the properties of liquid crystals, the structure of the liquid crystal molecules and the molecular motion in various types of mesophase1. Among more than 50 papers dealing with liquid crystals only a few consider the influence of electric field on mesophase vibrational spectrum. First Nelf2has used the electric field to orient nematic samples of p-methoxybenzylidene p′-cyanoaniline for the investigations of IR dichroism. Assuming that a large liquid crystalline domain acts like a rigid dipole and taking into account the effects of the walls an expression for the dichroism ratio was derived to evaluate the degree of orientational order. Later, Ohnishi3has applied a d.c. electric field to a cell filled with MBBA and studied the changes in the relative transmittance of some bands in the region 4000–1000 cm−1of the dynamic scattering mode. Pan and Wang4found that in the presence of turbulence due to the application of electric field, the intensity of all Raman bands decreases drastically but without any shift in the peak positions.

ISSN:0038-7010    

DOI:10.1080/00387017708065013

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The vibrational frequencies for diphenyl selenide, diphenyl telluride, diphenyl diselenide, diphenyl ditelluride, diphenyl disulfide mercury and diphenyl diselenide mercury have been assigned and were consistent with the vibrational assignments for diphenyl ether, diphenyl sulfide and diphenyl disulfide previously reported. The vibrational assignments for diphenyl telluride confirmed the linearity of the Gordy Rule plot for the t-vibration of Group VI A elements.

ISSN:0038-7010    

DOI:10.1080/00387017708065014

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The High and Low Frequency Separation (HLFS) method is reformulated in terms of mean square amplitudes and/or in terms of force constants and mean square amplitudes. The obtained equations, in matrix form, may be of use in computing “pseudo exact mean amplitudes” and/or “pseudo-exact force constants” from mean amplitudes.

ISSN:0038-7010    

DOI:10.1080/00387017708065015

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Empirical correlation relationships are presented between vibrational frequencies and force constants on one hand and bond lengths on the other, characterizing the SO2group for a series of simple sulphone molecules.

ISSN:0038-7010    

DOI:10.1080/00387017708065016

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The possibilities of formation of hydrogen bonds and metal bonds as a result of the interaction of aromatic nucleus with its substituents in 2-carbonyl-3-oxy derivatives of naphthalene have been discussed.

ISSN:0038-7010    

DOI:10.1080/00387017708065017

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Dramatic enhancement of the strength of absorption has been demonstrated for vibrations related to hydrogen bonding. The NH2deformations have been shown to be extremely temperature dependent. The vibrational spectrum of 4-amino-3-pentene-2-one is reported at room temperature and at liquid N2temperature. Spectra recorded in CCl4are also reported.

ISSN:0038-7010    

DOI:10.1080/00387017708065018

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The first order semiconductor - metall phase transition with the lattice symmetry change from monoclinic to tetragonal and the conductivity jump of several orders of magnitude is observed in pure vanadium dioxide and the dioxide doped by varios impurities [I]. Transition temperature Ttfor pure VO2is 68°C and depends on the impurity. For example, the impurities which enter the insulating phase as pentavalent ions Nb5+[2] give rise to a decrease in metal-semiconductor transition temperature at low concentrations and the trivalent ions Cr3+, Fe3+[3,4] lead to an increase in Tt. In the latter case three different monoclinic phases are stabilized at a temperature below Tt. It has been already shown [5] that for double doping of vanadium dioxide by pentavalent Nb5+and trivalent Fe3+or Cr3+ions three semiconductor phases exist (MI, M2, M3) but the transition temperature decreases as the impurity concentration increases.

ISSN:0038-7010    

DOI:10.1080/00387017708065019

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Recent studies concerning uranium plasma chemistry have confirmed the generally complicated nature of uranium chemistry1. Uranium plasma, generated by either rf-heating or dc arc torch argon heating of uranium hexafluoride, tends to react with its environment to produce among other compounds both fluorides and oxy-fluorides. The products are characterized as amorphous, powdery deposits. While uranyl fluoride can be identified readily by its infra-red absorption band, uranium tetrafluoride is not easily analyzed by any routine, non-destructive technique. Procedures such as Ion Scattering Spectroscopy and Secondary Ion Mass Spectrometry are expensive and time consuming; while, X- ray and electron deffraction can not overcome the amorphous nature of the plasma deposits.

ISSN:0038-7010    

DOI:10.1080/00387017708065020

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:0038-7010    

DOI:10.1080/00387017708065011

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor