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991.
Back Cover: Engaging Copper(III) Corrole as an Electron Acceptor: Photoinduced Charge Separation in Zinc Porphyrin–Copper Corrole Donor–Acceptor Conjugates (Chem. Eur. J. 4/2016) 下载免费PDF全文
992.
This pioneering experimental work is a proof of concept in which ultrasonic flexural waves have been imaged in a spatially and temporally resolved manner. Thin vibrating plates made of mirror glass and carbon/epoxy composite have been used in the experiments. Results obtained via a standard approach (scanning laser Doppler vibrometry) and the novel methodology based on deflectometry have been compared with a multi-physics finite element simulation. There is a very good correlation between the two experimental techniques. The numerical model provides insight into the experiments, but differs in its detailed structure due to uncertainties over material properties. The extreme slope resolution of deflectometry allows the measurement of peak-to-peak deflections of a few tens of nanometres in one shot. The use of an ultra-high speed camera allows for both space and time resolved measurements of Lamb waves which, to the best knowledge of the authors, has never been reported before. The limitations of the technique arise from the need for a flat specularly reflective surface. However, coating is possible for non-reflective materials and extension to moderately curved surfaces is possible in the future. 相似文献
993.
Structural Chemistry - Mephedrone (4-methyl-meth-cathinone) or 4-MMC and its derivative 3-MMC are analogs of cathinone which act as non-selective substrates for monoamine transporters, facilitating... 相似文献
994.
995.
L. C. Levoir und R. W. Hill 《Fresenius' Journal of Analytical Chemistry》1896,35(1):553-554
Ohne Zusammenfassung 相似文献
996.
Abstract As a transformer ages, the chemical and physical properties of the cellulose insulation materials in the transformer change, and the paper loses its strength and becomes brittle. The average molecular weight of the cellulose chains decrease with age, and degradation products are formed, including water, carbon monoxide, carbon dioxide, and furans. The molecular weight changes in the cellulose have been studied by several methods, but the GPC method for determination of the molecular weight has been shown to offer advantages over other methods because it yields the total molecular weight distribution. The tensile strength of the cellulose insulation in transformers also changes with age as a result of the changing molecular weight of the cellulose. Work carried out in our laboratory on the aging of cellulose insulation is reviewed in this paper. Our studies have included investigations of insulation materials from retired transformers as well as accelerated aging of insulation paper in transformer oil in the temperature range of 129–166°C under vacuum. In the study the relationships between the molecular weight of the cellulose and the furan degradation products and tensile strength have been delineated, and they have been correlated with information on the kinetics of degradation of the insulation paper. 相似文献
997.
A low runtime DCA model, ALICE, is used to model the few available photoionised plasma experiments that use both laser and pulse power devices. Modelling photoionised plasmas provides a computationally intensive problem which must therefore be solved by careful approximation emphasising the underlying physics. We will demonstrate the relative importance of the completeness of the set of configurations considered compared to the set of rates used in the model and draw conclusions as to how ALICE and other models may be improved for future use. 相似文献
998.
J.P. Hill C.S. Nelson M. v. Zimmermann Y.-J. Kim D. Gibbs D. Casa B. Keimer Y. Murakami C. Venkataraman T. Gog Y. Tomioka Y. Tokura V. Kiryukhin T.Y. Koo S.-W. Cheong 《Applied Physics A: Materials Science & Processing》2001,73(6):723-730
We review our recent X-ray scattering studies of charge and orbital order in doped manganites, with specific emphasis on the
role of orbital correlations in Pr1-xCaxMnO3. For x=0.25, we find an orbital structure indistinguishable from the undoped structure and long-range orbital order at low
temperatures. For dopings 0.3≤x≤0.5, we find scattering consistent with a charge and orbitally ordered CE-type structure.
While in each case the charge order peaks are resolution limited, the orbital order exhibits only short-range correlations.
We report the doping dependence of the correlation length and discuss the connection between the orbital correlations and
the finite magnetic correlation length observed on the Mn3+ sublattice with neutron-scattering techniques. The physical origin of these domains, which appear to be isotropic, remains
unclear. We find that weak orbital correlations persist well above the phase transition, with a correlation length of 1–2
lattice constants at high temperatures. Significantly, we observe similar correlations at high temperatures in La0.7Ca0.3MnO3, which does not have an orbitally ordered ground state, and we conclude that such correlations are robust to variations in
the relative strength of the electron–phonon coupling.
Received: 22 May 2001 / Accepted: 4 July 2001 / Published online: 5 October 2001 相似文献
999.
John S. Forsythe David J. T. Hill A. K. Whittaker 《Radiation Physics and Chemistry》2001,60(6):609-615
The radiation chemistry of two TFE/PMVE copolymers with TFE mole fractions of 0.66 and 0.81 has been studied under vacuum using 60Co γ-radiation over absorbed dose ranges up to 4.2 MGy. The radiolysis temperature was 313 K for both TFE/PMVE copolymers. New structure formation in the copolymers was identified by solid-state 19F NMR and the G-values for new chain ends of 2.1 and 0.5 and for branching sites of 0.9 and 0.2 have been obtained for the TFE/PMVE with TFE mole fractions of 0.66 and 0.81, respectively. The relative yields of –O–CF3 and –CF2–CF3 chain ends were found to be proportional to the copolymer composition, but the yields of the –CF2–CF3 chain ends and –CF– branch points were not linearly related to the composition, rather they were correlated with the radical yields measured at 77 K. 相似文献
1000.
Competitive sorption between glyphosate and inorganic phosphate on clay minerals and low organic matter soils 总被引:1,自引:0,他引:1
H. H. Hill Jr. 《Journal of Radioanalytical and Nuclear Chemistry》2001,249(2):385-390
Inorganic phosphate may influence the adsorption of glyphosate to soilsurface sites. It has been postulated that glyphosate sorption is dominatedby the phosphoric acid moiety, therefore, inorganic phosphate could competewith glyphosate for surface sorption sites. We examine sorption of glyphosatein low organic carbon systems where clay minerals dominate the available adsorptionsites using 32P-labeled phosphate and 14C-labeled glyphosateto track sorption. We found glyphosate sorption strongly dependent on phosphateadditions. Isotherms were generally of the L type, which is consistent witha limited number of surface sites. Most sorption on whole soils could be accountedfor by sorption observed on model clays of the same mineral type as foundin the soils. 相似文献