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991.
J. D. Henry Jr. M. E. Prudich K. R. Vaidyanathan 《Separation & Purification Reviews》2013,42(2):81-118
The removal of the mineral matter found in coal derived liquids is a very difficult solid/liquid separation process. Clays, pyrites and other minerals that occur in coal ultimately find their way into the liquefied product. This is the case, e.g., for both the solvent refined coal (SRC-I) and H-Coal processes. The ash content of bituminous coals which may be fed to coal liquefaction processes normally rangesfrom 6 to 11 wt.%. The ash content of the coal liquid product can range from 4 to 20 wt.% depending upon the lique-faction .process. Ash levels must be reduced to, e.g., 0.4 wt.% in the case of boiler fuel and less than 0.1 wt.% for gas turbine fuels. 相似文献
992.
993.
Dietrich Gudat Martin Schrott 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4)
Abstract Examples for 2-D shift correlations between 31P and another heteronucleus via nX-detected 2D-INJZPT or 31P-detected HMQC experiments are presented. The former technique is best suited for 31P, 15N correlations and permits the determination of intramolecular connectivities as well as of relative signs of couplings.1 The “inverse” HMQC expenment allows easy recording of the 77Se NMR spectrum of an equilibrium mixture of 2 and 33, disregarding the severe exchange broadening of the 77Se-resonances 相似文献
994.
Matthias Dehmer Martin Grabner Abbe Mowshowitz Frank Emmert-Streib 《Advances in Computational Mathematics》2013,39(2):311-325
The search for an easily computable, finite, complete set of graph invariants remains a challenging research topic. All measures characterizing the topology of a graph that have been developed thus far exhibit some degree of degeneracy, i.e., an inability to distinguish between non-isomorphic graphs. In this paper, we show that certain graph invariants can be useful in substantially reducing the computational complexity of isomorphism testing. Our findings are underpinned by numerical results based on a large scale statistical analysis. 相似文献
995.
Leonid S. Zakharov Galina N. Molchanova Tat'yana M. Shcherbina Pavel V. Petrovskii Martin I. Kabachnik 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1)
Abstract We have studied the phosphorylation of 1-polyfluorólkyl-2-trialkylsilylethanols (I) with phosphorus acids chlorides. 相似文献
996.
Martin Pomerantz Whe-Narn Chou 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4)
Abstract A series of N-phenyl-P,P,P-triarylphospha-λ5-azenes (1) as well as their l5N labeled analogs was synthesized. The 13C, 31P, and 15N NMR spectra of this series and those of two other series of related compounds, namely triarylphosphines (2) and triarylphosphine oxides (3), were measured and are reported. Many satisfactory correlations using the mono-substituent parameter (MSP) and the Taft dual-substituent parameter (DSP) treatments with the 13C substituent chemical shifts (SCS), 31P SCS, 15N SCS and the one bond P-N, P-C and C-N coupling constants were observed and will be discussed. Thus, for example, the 31P and 15N chemical shifts in 1 correlated with [sgrave]?with negative slopes while the 31P chemical shifts in 3 correlated with those in 1 with a slope of 2.0. The 13C chemical shifts in 1 correlated excellently with the corresponding ones in 3 with slopes very close to unity. The substituent effects on the chemical shifts of the various nuclei were shown to be mainly due to changes in the charge distribution on those nuclei. In 1 the one bond P-N and P-C coupling constants correlated with [sgrave]p and [sgrave]R respectively. The one bond P-C coupling constants of 1 correlated quite well with those of 3 with a slope of 0.93 while the corresponding correlation of 1 with 2 was quite poor. Taft DSP treatment of 1JPCin 1 and 3 were quite similar, ρI and ρR were both negative and ρR was much larger than ρI. Series 2 showed behavior which was different from that shown by 1 and 3 but similar to that shown by other systems with a lone electron pair on the atom bound to the phenyl ring. The substituent effects on the one bond P-N, P-C and C-N coupling constants will be discussed in terms of bonding and hybridization changes between the directly bonded nuclei. 相似文献
997.
998.
In this paper we extend the well-known Leinfelder–Simader theorem on the essential selfadjointness of singular Schrödinger operators to arbitrary complete Riemannian manifolds. This improves some earlier results of Shubin, Milatovic and others. 相似文献
999.