摘要:

The geometry of the phenylthallium dihalides, PhTlX2(X=F, Cl or Br) which has heitherto been unknown, has been proposed on the basis of several qualitative aspects and quantitative arguments. These molecules have a planar structure with C2vsymmetry and the ring geometry has been assumed to be the same as that of benzene. The ring-substituent bond length has been taken to be 2.218 A° in all the three molecules, and the Tl-F, Tl-Cl and Tl-Br bond lengths in respective molecules have been estimated to be 1.878, 2.366 and 2.520 A°. The remaining parameter inter-bond angle, F-Tl-F has been taken to be 116° in PhTlF2, whereas, angles Cl-Tl-Cl and Br-Tl-Br in respective molecules have been taken to be 120°, as expected in the case of a pure sp2hybridization.

ISSN:0038-7010    

DOI:10.1080/00387018108062615

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The applicability of the modified hollow cathode emission source to the determination of some elements usually contained in steel was tested in the case of chromium (0.144 – 3.07%), copper (0.090 – 0.49%), manganese (0.016 – 1.42%), molybdenum (0.007 – 1.41%), nickel (0.048 – 5.15%, silicon (0.013 – 0.81%), and vanadium (0.034 – 0.64%). The linearity of the calibration curves was found to be highly satisfactory, the Bravais - Pearson correlation coefficient ranging from 0.97 to 0.99. Moreover, results showed that background intensity is negligible and that blackening values can be plotted without resorting to internal standards or other preliminary corrections.

ISSN:0038-7010    

DOI:10.1080/00387018108062616

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Leukotrienes A-E are an important family of arachidonic acid metabolites of great current interest; several being associated with major allergic responses in man. Leukotriene D is the most important member of this series and accounts for nearly all of the SRS-A activity in human lung.1

ISSN:0038-7010    

DOI:10.1080/00387018108062617

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

In practical spectrophotometry it has not been customary to describe the band profile in greater detail than can be achieved with such parameters, as position, height, and width, but, with increasing precision in measurement a more precise description of the profile becomes desirable. These are statistical problems, and can conveniently be handled by the method of moment analysis.

ISSN:0038-7010    

DOI:10.1080/00387018108062618

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Raman and far infrared spectra (in the frequency range 20–360 cm−1) have been recorded for polycrystalline samples of six crystals having the cadmium iodide layered structure. The four fundamental zone-center vibrational frequencies are assigned for CoBr2, FeBr2, MgBr2, MnBr2, CdI2and MgI2. Values of the principal interlayer force constants are deduced from a simple linear chain dynamical model, and comparisons are made with recent results from spectroscopic studies of crystals with the related cadmium chloride structure.

ISSN:0038-7010    

DOI:10.1080/00387018108062619

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Employing the techniques of a circular dichroism (CD) and a fluorescence polarization (FP), the long-wavelength forbidden1A*-g→1A−gtransition in the absorption spectrum of retinyl acetate at 293K has been found. The FP degree of retinyl acetate in cyclohexanol decreases from 0.28 at 330 nm (the area of a strongly allowed1B*u→1A−gtransition) to 0.21 at 360 nm (the area of forbidden1A*-g→1A−gtransition).

ISSN:0038-7010    

DOI:10.1080/00387018108062620

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The N2laser excited fluorescence spectrum and the intensity of fluorescence of oxalyl chloride C2O2Cl2) condensed at 77°K either alone, or, diluted with a non-hydrocarbon or a hydrocarbon with dilution ratios ranging from 10 to 100 were studied. A slow condensation of the hydrocarbon matrix diluted sample showed a considerable reduction in the fluorescence intensity as compared to a fast condensation of the same sample.

ISSN:0038-7010    

DOI:10.1080/00387018108062621

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Previous work in these laboratories1and elsewhere2,3has pointed to the value of a mixture of lanthanide fod chelates with silver fod1,2or with silver trifluoroacetate3in simplifying the1H NMR spectra of aryl substrates which do not possess the conventional (O or N) donor groups (fod = 2,2-dimethyl-6,6,7,7,8,8,8-heptafluoro-3,5-octane dionate).

ISSN:0038-7010    

DOI:10.1080/00387018108062622

出版商:Taylor & Francis Group    

年代:1981

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:10.1080/00387018108062614

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor