摘要:

The absorption, fluorescence and photo-acoustic spectra of flavomonnnucleotide (FMM) molecules embedded in polyvinyl alcohol film were measured for illuminated and for stored in darkness samples. The effect of illumination depends an pigment concentration, and it is connected with FMN excimers formation. The FMN excimer formation prevented the photodestruction of isoatloxazine ring.

ISSN:0038-7010    

DOI:10.1080/00387018808082325

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A nitrogen compound of mercury (1) was prepared by reaction of 1,10 phenanthroline with mercurous nitrate. The mass spectra of this resulting precipitate was made and its distinguished features have been discussed. The results of various investigations suggest that disproportionation of the Hg(I) state did not occur.

ISSN:0038-7010    

DOI:10.1080/00387018808082326

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The cross-polarization (CP) technique1–2, combined with magic angle sample spinning (MAS)3,4and high power decoupling5, usually provides high resolution spectra of solids2,6–8. These high resolution13C NMR spectra are in many cases sufficiently detailed to characterize the system9–17In the case of polyethylene (PE), it was shown that distinct conformations in the crystalline regions lead to a narrow crystalline resonance and the non-crystalline regions appear as a broad shoulder on the upfield side. 14 Since it is often difficult to obtain detailed information from unresolved spectra, it is either desirable to resolve these peaks or isolate one resonance peak from another by alteration of the measurement.

ISSN:0038-7010    

DOI:10.1080/00387018808082327

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A new simple and rapid quantitative proton magnetic resonance method has been developed for the determination of diclofenac sodium in pure and tabler forms. Among other peaks, the PMR spectrum of diclofenac has a well defined sharp singlet (at ≃ 3.62 ppm) which is chosen for quantitative measurements. The method involves co-paring the integral of this signal to that of a sharp singlet of anhydrous sodium acetate (at ≃ 1.85 ppm) which is used as internal standard.

ISSN:0038-7010    

DOI:10.1080/00387018808082328

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The complexes of nickel and copper with the reagent 5,5-dimethyl -1,2-3- cyclohexanetrione 1,2,-dioxime 3-thiosemicarbazone have been studied. Properties of these complexes such as composition stability constant and free energy change of formation have been determined. These complexes have been used to develop spectrophotometric methods for the analysis of nickel and copper in aqueous solutions. Sensitivities and ranges of application of these methods have been determined. The optimum conditions for maximum sensitivity such as wavelength,pH and etanding time have been determined.The effect of foreign ions on these methods has been also investigated .

ISSN:0038-7010    

DOI:10.1080/00387018808082329

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A simple method is described for accurately measuring spin lattice relaxation times in the presence of large probe background resonances. The method relies on selectively exciting those spins which are In the center of the rf coil, by employing pulse schemes which were developed for surface coil studies. The accuracy of the technique is checked by measurements on camphor in the solid state.

ISSN:0038-7010    

DOI:10.1080/00387018808082330

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A quantitative procedure for the determination of dapsone [80-08-0], I, in authentic mixtures and tablets, II, has been developed using the PMR spectroscopy. The comparison of the proposed PMR method with the official assays of the B.P. 1980 was achieved, and the results were statistically evaluated. The PMR determination is fairly accurate, more precise and providing advantageous traits regarding the simplicity and the rapidity of the method as well as the specificity of the technique in identifying and testing the purity of the compound.

ISSN:0038-7010    

DOI:10.1080/00387018808082331

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

During an investigation of the triterpenoid glycosides constituents of Hedera helix we isolated the previously reported Hederasaponin C. Through the concerted application of 2D-homonuclear and heteronuclear chemical shift correlations total assignment of13C and1H NMR spectra was achieved.13C NMR data for two other saponins, Hederasaponin B and saponin K10, are also reported. Hederasaponin K10 was isolated for the first time in Hedera Helix leaves.

ISSN:0038-7010    

DOI:10.1080/00387018808082332

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Despite the fact that khSO4and KHSeO4are isomorphous, the infrared spectra of these compounds are remarkably different. The characteristic 'A, B, C' trio is present in the spectrum of KHSeo4whereas multiplet structure of the o-H stretching band is found in KHSO4. On lowering the temperature, the bands in the 3000–2000 cm−1region become more structured and new bands appear in the 2000–1500 cm−1interval. Deuteration causes marked changes in the infrared spectra, as expected for strongly hydrogen bonded systems, although the Raman spectra are largely unaffected. Assignments in terms of separate R-O(H) and RO3units are presented.

ISSN:0038-7010    

DOI:10.1080/00387018808082333

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Using: semiclassical calculation the centrifugal distortion constants have been obtained for the X1σ+, A3II0and B3II1electronic states of InBr.

ISSN:0038-7010    

DOI:10.1080/00387018808082334

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor