摘要:

Thin polymer films occupy an eminent position in modern science and technology both in and of themselves and as models for bulk polymer systems. Much of their function depends on their interaction with external (often hostile) environments. Thus, methods for obtaining information about the chemistry of these films as a function of depth are a critical need. This review critically evaluates the methods which have been applied up to this point for depth profiling in polymers and concentrates on two methods: optical depth profiling using excitation in a slab waveguide, and nuclear reaction profiling. Guided wave experiments have been useful in situations in which the species being determined forms only a minor or trace constitutent of the thin film matrix, while nuclear reaction profiling has been applied primarily to profiles of protonated and deuterated polymers in studies of interdiffusion. Other techniques for depth profiling have more limited applications.

ISSN:1040-8347    

DOI:10.1080/10408349108055023

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Ion mobility spectrometry (IMS) was first introduced in the late 1960s as an instrumental technique for detecting organic compounds at trace concentrations in air. Despite certain at tractive features of IMS in environmental mon itoring and laboratory studies, the growth of IMS from 1970 to 1980 exhibited some disappointing trends as suggested in Figure 1. Interest in IMS declined generally after 1976 by what may be ascribed to a broad disenchantment from unmet expectations and misunderstanding of response characteristics. A new cycle of interest in IMS began 1980 resulting in advances in all aspects of IMS. Additionally, small rugged IMS units suited for operation in hostile environments became available in fulfillment of the purposes originally suggested for IMS. This has occurred through unpublicized developmental programs within military establishments of the U.S. and the U.K.

ISSN:1040-8347    

DOI:10.1080/10408349108055024

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Several research groups have been actively designing flow systems for automatic or semiautomatic liquid-liquid extraction, most of them using air-segmented flow systems. The first application of liquid-liquid extraction in flow injection analysis (HA) was carried out simultaneously by Karlberg et al.1and Bergamin et al.2in 1978. Since then, a large number of analytical pmcedures have been devised in combination with all common detection systems.3–6

ISSN:1040-8347    

DOI:10.1080/10408349108055025

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Hydroxyoximes are well established copper extractants that are used in several high-scale in- dustrial installations for producing cathodic copper from oxide ores. The most economically produced copper is obtained by means of hydrometallurgical processes in which hydroxyoximes are used to separate the copper from iron and to concentrate its aqueous solution. The industrial application of hydroxyoxime extractants and their properties have been discussed in several previous papers. *-I 3 Some comprehensive reviews of the chemistry of transition metal complexes with oximes have been presented. 14 v L5 The kinetics and mechanism of metal extraction with hydroxyoximes were also reviewed. 1.11 13,16 The aim of this work is to review the chemistry of metal extraction with hydrophobic hydroxyoxime extractants, with emphasis upon: (1) the characterization of the composition and stability of hydroxyoxime complexes with metals; (2) hydroxyl group acidity; and (3) pH, values, including the effect of hydroxyoxime structure. Appropriate tabular data are presented.

ISSN:1040-8347    

DOI:10.1080/10408349108055026

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

X-ray photoelectron spectroscopy (XPS or ESCA) has reached a state of maturity in which some of its common uses may be considered routine. There is a danger, however, in the possible over-interpretation of this status. (Consider, for example, the hundreds of incorrect ESCA analyses in high Tcsuperconductivity.) Thus, although recent advances in instrumentation have simplified general operations, they have also clearly identified a variety of previously undetected or misunderstood features in the technique that seem to suggest the potential of a more powerful analysis tool. These new areas require a much more sophisticated understanding of the photoelectron process and its potential uses. In the present article we provide a description of the background, present status, and possible future uses of some of these features of photoemission spectroscopy, including: (1) the charging shift and Fermi edge referencing, (2) valence band analysis, (3) XPS induced loss spectroscopy, (4) surface-to-bulk chemical shifts, (5) small cluster analysis, (6) photoelectron microscopy, (7) inverse photoemission, (8) resonance photoemission, (9) photoemission of adsorbed xenon, (10) photoelectron diffraction, and (11) liquid phase photoemission. (Some prejudicial discretion has been exercised in the degree of emphasis on each of these topics.) Novel analyses are described of various oxides (including zeolites and high Tcsuperconductors), inert hydrocarbon polymers, carbon filled metal ceramics, supported metals catalysts, unique structures, and a variety of other systems. This review is divided into two parts. The first part treats the developmental and theoretical background of ESCA in detail, including established ESCA procedures (up to recent studies of the causes and uses of loss spectroscopy in ESCA), laying the basis for the description and elaboration of promising new directions in ESCA given in part two of this review. This two-part work is intended to serve as a useful treatise defining the underlying characteristics and broad capabilities of the ESCA technique.

ISSN:1040-8347    

DOI:10.1080/10408349108055027

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

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

ISSN:1040-8347    

DOI:10.1080/10408349108055022

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor