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141.
The glass-transition region of crosslinked polymers prepared from poly(1,2-propylene phthalate fumarate) and styrene was studied using a torsion pendulum. The glass-transition temperature and the modulus in the rubbery region of these polymers were analyzed in terms of the crosslink density. The styrene concentration at which the maximum crosslink density occurs, as estimated from the viscoelastic data, is found to be in agreement with estimates made by other workers using chemical methods. 相似文献
142.
John E. Arrowsmith Michael J. Cook David J. Hardstone 《Magnetic resonance in chemistry : MRC》1978,11(3):160-161
Carbon-13 chemical shifts for N-benzylidenebenzylamines are affected by substituents up to eleven bonds away from the substituent group. The data correlate well with Hammett constants. 相似文献
143.
C.D. Stinespring Jason M. Cook 《Journal of Electron Spectroscopy and Related Phenomena》1983,32(2):113-122
The adsorption of SO2 on CaO (100) at 300 K has been studied using X-ray photoelectron spectroscopy. Under ultrahigh-vacuum conditions, the surface was exposed to 0–500 Langmuirs of SO2. The resulting adsorption yields a single SO surface species with an S 2p peak at 168.2 eV and an O 1s peak at 531.7 eV. Subsequent heating of the exposed surface to 673 K indicated no desorption or changes in the binding energies of the S 2p and O 1s peaks. On the basis of these data and binding-energy data for standard compounds, the adsorbed species is identified as SO42?. The surface coverage due to the SO42? species was also measured as a function of SO2 exposure. From these data, the initial adsorption is found to be first-order in surface coverage, and the initial sticking probability is found to have a value of 0.4. 相似文献
144.
145.
S. L. Cook 《The Journal of the Operational Research Society》1965,16(2):145-175
University education for operational research in Britain is making great and welcome strides forward, but there has been little open discussion of its aims in relation to the advance of the profession. Progress in operational research, and in its application to the really worth-while problems of industry in particular, depends primarily on strengthening the industrial operational research group in its “front line” role. We need a research study of the teaching and practice of industrial operational research, in relation to effectiveness. We need “collaborative” programmes of operational research education in which the university and the industrial operational research group each contribute, in a man's training over a period of years, in the ways in which each is most competent. We need emphasis on “breadth” as well as “depth” in operational research education, and greater attention to the mutual contributions of operational research, teaching and practice, and the teaching and development of management. An impressionist sketch of a programme which might meet these needs is put forward for discussion of principles and feasibility. 相似文献
146.
Marshall LJ Williams JR Almond MJ Atkinson SD Cook SR Matthews W Mortimore JL 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,61(1-2):233-241
Three ochre samples (A (orange-red in colour), B (red) and C (purple)) from Clearwell Caves, (Gloucestershire, UK) have been examined using an integrated analytical methodology based on the techniques of IR and diffuse reflectance UV-visible-NIR spectroscopy, X-ray diffraction, elemental analysis by ICP-AES and particle size analysis. It is shown that the chromophore in each case is haematite. The differences in colour may be accounted for by (i) different mineralogical and chemical composition in the case of the orange ochre, where higher levels of dolomite and copper are seen and (ii) an unusual particle size distribution in the case of the purple ochre. When the purple ochre was ground to give the same particle size distribution as the red ochre then the colours of the two samples became indistinguishable. An analysis has now been completed of a range of ochre samples with colours from yellow to purple from the important site of Clearwell Caves. 相似文献
147.
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149.
The intensity of the water-induced γ relaxation (see ref. 1) in crosslinked polyester networks in creases rapidly at low water concentrations (0 to 0.5% by weight). At higher water concentrations (0.5 to 3.0%) the intensity of the γ relaxation approaches a constant value. The shift of the relaxation peak to lower temperatures shows a similar pattern of behavior. These results have been related to the fraction of water involved in the relaxation and the changing nature of the relaxation sites with the increase in water concentration. The important role that fumarate units play in the γ relaxation has also been confirmed; however, the chemical nature of the relaxing unit appears to be more complex than was originally considered. Two models are proposed for this behavior. 相似文献
150.
1-(3,4-Dichlorophenyl)-2-pyrrolidinone (I) has been condensed at the 3-position with a series of aldehydes, ketones and esters. 相似文献