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1.
Consider a semigroup generated by matrices associated with an edge-coloring of a strongly connected, aperiodic digraph. We
call the semigroup Lie-solvable if the Lie algebra generated by its elements is solvable. We show that if the semigroup is
Lie-solvable then its kernel is a right group. Next, we study the Lie algebra generated by the kernel. Lie algebras generated
by two idempotents are analyzed in detail. We find that these have homomorphic images that are generalized quaternion algebras.
We show that if the kernel is not a direct product, then the Lie algebra generated by the kernel is not solvable by describing
the structure of these algebras. Finally, we discuss an infinite class of examples that are shown to always produce strongly
connected aperiodic digraphs having kernels that are not right groups. 相似文献
2.
This paper examines the performance of Commodity Trading Advisors (CTAs) using fixed and variable benchmarking models. In
order to avoid the troublesome passive and active commodity and managed futures benchmarks (indices) when examining the performance
of CTAs, we innovate by using data envelopment analysis (DEA). Because this alternative class has non-linear returns due to
long/short positions, and derivatives (i.e., dynamic trading strategies), DEA can alleviate the problems usually associated
with these indices. The effectiveness of using benchmarking models in a DEA setting will provide investors with an alternative
technique in assessing the performance and identifying efficient CTAs. 相似文献
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4.
M. Mikoŀajczyk J. Michalski A. Halpern R. Sochaxcka 《Monatshefte für Chemie / Chemical Monthly》1969,100(4):1266-1273
Zusammenfassung An den Modellverbindungen Dialkylchlorthiophosphat (RO)2P(S)Cl (R=Me, Et, n-Pr) und Diphenylchlorthiophosphat (PhO)2P(S)Cl wurde der Austausch Chlorid—Radiochlorid am Thiophosphorylzentrum untersucht. Die bimolekularen Geschwindigkeitskonstanten, die Aktivierungsenergien und Aktivierungsentropien wurden berechnet. Der Einfluß von Substituenten auf bimolekulare Substitutionsreaktionen am vierfach koordinierten Phosphoratom wurde diskutiert.
Mit 3 Abbildungen 相似文献
Chlorine isotopic exchange at phosphorus atoms, I.: Chloridothiophosphates
The chloride—radiochloride ion exchange at the thiophosphoryl centre has been studied using dialkylchloridothiophosphates (RO)2P(S)Cl (R=Me, Et, n-Pr) and diphenylphosphorochloridothionate, (PhO)2P(S)Cl, as model compounds. The bimolecular rate constants, energies and entropies of activation have been calculated. Effects of the substituents in the bimolecular displacement reaction on four-coordinated phosphorus atom have been discussed.
Mit 3 Abbildungen 相似文献
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A response equation for conductivity detection in ion chromatography has been derived. This equation is applicable to non-suppressed ion chromatography using both fully ionised and partially ionised eluents. A prime assumption of this equation is that when partially ionised eluents are used (such as benzoic acid), both the ionised and neutral components of the eluent species contribute to the detector response of anionic analytes. Experimental evidence is provided to support this assumption in that pH changes accompanying the elution of an analyte have been measured. These pH changes are proportional to the concentration of analyte injected onto the column, in accordance with predictions from the response equation. Furthermore, it is shown that protonated eluents (such as benzoic acid) give more sensitive detection than equivalent ionised eluents (such as potassium benzoate) and the signal enhancement achieved using a protonated eluent species is in accordance with theory. 相似文献
8.
Thomas F.O. Lim Jerry K. Myers Greg. T. Rogers Paul Ronald Jones 《Journal of organometallic chemistry》1977,135(2):249-259
The regioselectivity of the hydroboration of the methylchlorovinylsilanes, ClnMe3?nSiCHCH2 (n= 0 ? 3), has been investigated using BH3←THF, 9-BBN, disiamyl- and dicyclohexylborane. Methylation of the adducts with methylmagnesium bromide is complicated by formation of tetraalkylboronates. Alkaline hydrogen peroxide oxidation of the boronates gives reasonable yields of the corresponding α- and β-trimethylsilylethanols forn= 0 and 1. Forn= 2 and 3, conversion of the adducts to the corresponding α- and β- deuteroethylsilanes by treatment with excess sodium methoxide in methanol-0-d provides a more effective means of derivatization. Addition of the alkenes,n= 2 or 3, to excess BH3←THF givesca. 90% of the α-boro-organo-chlorosilanes. For all of the alkenes, the dialkylboranes giveca. 80% of the β-boron adducts. 相似文献
9.
Marek Trojanowicz Joanna Szpunar-Łobińska Zdzislaw Michalski 《Mikrochimica acta》1991,103(3-4):159-169
An original computer-controlled solid-state photometer has been developed and its potential for simultaneous multicomponent flow-injection analysis of binary and ternary mixtures is demonstrated. The device is simple in construction. Its principle of operation is based on rapid sequential measurements of the absorbance of the complexes formed by the analytes with chromogenic reagents at the wavelengths corresponding to the emission maxima of three light emitting diodes (563, 580 and 638 nm). 相似文献
10.
Guldi DM Zilbermann I Anderson G Kotov NA Tagmatarchis N Prato M 《Journal of the American Chemical Society》2004,126(44):14340-14341
Novel organic (positively charged fullerene)-inorganic (negatively charged CdTe nanoparticle) nanoensembles were devised through electrostatic interactions and probed as versatile donor-acceptor hybrids. Photoirradiation of their homogeneous solutions, containing the electrostatically packed components, let to very long-lived (1.3 ms) charge separated states. 相似文献