摘要:

Biomer is a segmented polyether/polyurethane in which the monomer of the polyether is tetramethylene oxide and the urethane linkages are with toluene-2,4-diisocyanate. Both the positive- and negative-ion laser desorption mass spectra of Biomer show peaks corresponding to fragments from the polyether and the polyurethane. Avcothane is also a segmented polyether/polyurethane, however polydimethylsiloxane is blended into this polymer. The polyether of Avcothane is polypropylene glycol and the urethane bond is formed using toluene-2,4-diisocyanate. The positive and negative ion mass spectra of Avcothane contain peaks which have been assigned to polyether, polyurethane, and polydimethylsiloxane components.

ISSN:0038-7010    

DOI:10.1080/00387018208062643

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Purge gas flow rates influence significantly the peak height and the peak area signal obtained in GF-AAS. With vaporization from the wall and gas stop more than 20% of the atoms are lost by convection because of their forced removal from the furnace by the expanding purge gas. With vaporization from a platform and gas stop the atoms are removed from the furnace solely by diffusion. Increasing flow rates affect the signal more if vaporization is made from the wall.

ISSN:0038-7010    

DOI:10.1080/00387018208062644

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The 0–0 and 0–1 bands of the B2σ+- X2π3/2subsystem have been recorded at high resolution and reanalyzed. Rotational constants for the74Ge35Cl,72Ge35Cl and70Ge35Cl molecules have been determined. New correct constants for the74Ge35Cl molecule have been derived.

ISSN:0038-7010    

DOI:10.1080/00387018208062645

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The13C-nmr spin-lattice (T1) relaxation times for the cembranoid diterpene sinularin have been re-examined. Results of this study indicate that the solution conformation of the molecule, particularly in the region surrounding the δ-lactone is highly comparable to that observed in the crystal structure. This conclusion is in direct contrast to a previous study which invoked a different conformation for this region of the molecule to account for a disparity between the calculated and observed T1relaxation times for the non-protonated carbons.

ISSN:0038-7010    

DOI:10.1080/00387018208062646

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Since the revival of interest in the photoacoustic effect with solids, prompted by Rosencwaig's work,1most papers dealing with the analytical applications of photoacoustic spectroscopy (PAS) have mentioned and even strongly stressed that one of the advantages of PAS is that sample preparation is not difficult. Such statements are, of course, generally true. What is usually done is to place the substance into a minimum-volume, non-resonant cell; the spectrum is then recorded. “Sample preparation” is thus minimal. However, with solids which are larger than the cavity of the sample cell, which usually is made as small as is feasible in order to increase the photoacoustic signal, such a procedure means that, literally, a sample has to be removed from the solid.

ISSN:0038-7010    

DOI:10.1080/00387018208062647

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

During our studies of the methanation reaction over Ni/SiO2catalyst we have employed mass spectroscopy to follow the redistribution of isotopes among the reactant and product species. When deuterium was employed in the studies,1a wide variety of isotopic species resulted. Among the species produced are H2O, D2O, and HOD. If accurate sensitivity and fragmentation data are available on the species in question, matrix algebra may be used to transform mass fragment data into concentrations. For example see the text by Roboz.2

ISSN:0038-7010    

DOI:10.1080/00387018208062648

出版商:Taylor & Francis Group    

年代:1982

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:10.1080/00387018208062642

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor