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James A. Ballantine Jonathan D. Barton James F. Carter Jeremy P. Davies Keith Smith Geoffrey Stedman Eric E. Kingston 《Journal of mass spectrometry : JMS》1988,23(1):1-5
The mass spectra of a number of aliphatic nitro compounds have been studied using electron Ionization (EI) and a variety of chemical Ionization (CI) techniques in attempts to obtain relative molecular mass information. The use of positive ion ammonia chemical Ionization techniques gave very satisfactory results, providing abundant [M + NH4]+ ions, not only from both primary and secondary nitro compounds, but also from the much more labile tertiary nitro compounds. However, the use of methane and isobutane positive ion CI or EI conditions resulted in facile fragmentation with little relative molecular mass information being made available. Negative ion CI using methane, isobutane or ammonia as moderating gases all gave abundant [M ? 1]? ions with primary and secondary nitro compounds but at much reduced sensitivity. 相似文献
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Coleman and Korté have restated and defended an earlier attempt to refute the traditional thesis of the conventionality of simultaneity within special relativity. Here we argue their attempt still fails and respond to criticisms of a paper in which we addressed the inadequacies of their earlier paper. The spatial criterion they use to argue for standard synchronization throughout an inertial frame is merely a definition and provides no demonstration that a unique distant simultaneity relation exists in nature. 相似文献
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K. U. Schreiber J. -P. R. Wells G. E. Stedman 《General Relativity and Gravitation》2008,40(5):935-943
Large ring lasers with a cavity Q well above 1012 are characterized by extremely narrow line-widths and high coherence. At this point, active Sagnac interferometers do not
quite reach the quantum limit. In this paper, we will explore the current status of this technology and look at the various
noise processes involved with large ring lasers rigidly mounted to the Earth crust. 相似文献
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Some aspects of the theory of superconductors in noninertial frames are clarified. Interference effects, such as that observed by Zimmerman and Mercereau on rotation of a SQUID, would be destroyed if the apparatus were shielded by a superconducting shell. 相似文献
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G.E. Stedman 《物理学进展》2013,62(4):513-587
Natural and induced linear and nonlinear processes are discussed from a unified viewpoint. In each case the dependences of a nonlinear optical process on the geometry of the experimental arrangement, including the polarization of the light beams, on the one hand, and on the physical couplings on the other are separated in an optimally efficient and convenient manner. The method is based on a generalization of the quantum theory of angular momentum, in diagram notation, to all molecular and crystal symmetry groups. Recent applications of such methods, including Raman and Compton scattering, magnetic circular dichroism, Raman optical activity and the hyper-Raman effect, are reviewed and extended. 相似文献
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Elution gas chromatography has been used to study complexing of hydrazoic acid with tributyl phosphate (TBP) in hexadecane solution in the presence of nitric acid and/or uranyl nitrate. The study covered the temperature range 298-338 K, with concentrations of either additive up to 0.41 mol dm(-3). The results for hydrazoic acid elution at infinite dilution establish (a) that stoichiometry of the TBP-HNO3 complex is 1:1 and (b) that both 2:1 and 1:1 TBP-UO2(NO3)2 complexes co-exist in the system, the latter increasing in amount as the temperature is raised. Both HNO3 and UO2(NO3)2 act simply to reduce the amount of TBP free to form the 1:1 TBP-HN3 complex. Stability constants for the equilibrium UO2(NO3)2 TBP+TBP4<-->UO2(NO3)2 x 2TBP are presented. 相似文献
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Class sum theory, the duality with IRREP methods and tensor operators in the group algebra are discussed by generalizing the diagrammatic approach of conventional IRREP theory to include group label manipulation. Concepts such as invariant nodes and Jucys–Levinson–Vanagas reduction theorems generalize straightforwardly. The results are capable of unique simplification for certain nodes, when the group rearrangement theorem is useable or when a class sum is performed. A duality transformation (between IRREP –partner and class–element labels) emerges as an important concept. 相似文献