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41.
42.
A simple, accurate and rapid voltammetric method has been developed for the quantitative determination of coenzyme Q10. Studies with direct current voltammetry were carried out using a glassy carbon electrode (GCE) in a phosphate buffer solution (pH 6.86). A well-defined oxidation peak of CoQ10 was obtained at -0.600 V vs Ag/AgCl. The magnitude of the oxidation peak current has been found to be related to the concentration of the coenzyme over the range of (2.010-5 to 2.010-4 M) (r = 0,991). Antioxidant activity of CoQ10 was investigated. 相似文献
43.
By referring to theorems of Donaldson and Hitchin, we exhibit a rigorous AdS/CFT-type correspondence between classical 2+1-dimensional vacuum general relativity theory on Σ×R and SO(3) Hitchin theory (regarded as a classical conformal field theory) on the spacelike past boundary Σ, a compact, oriented Riemann surface of genus greater than 1. Within this framework we can interpret the 2+1-dimensional vacuum Einstein equation as a decoupled “dual” version of the two-dimensional SO(3) Hitchin equations. 相似文献
44.
This paper gives a brief and systematic presentation of the computer simulation techniques of satellite communications, especially for a mobile satellite channel, based on a summarization of the author's exploration and experience in this area. It includes the equivalent complex baseband notation (ECBN) method, a very convenient mathematical form for software simulation; development of a multi-functional and expandable channel simulation system on a computer from L-band to Ka-band; channel impulse or frequency response estimation in real time by the technique burst-mode link analyser with least-squares algorithm (BMLA/LS), modelling and simulation of the channel fast fading due to multipath and shadowing; acquisition of the equivalent normalized binary signal-to-noise ratio (Eb/N0) data at the channel input; and bit-error rate (BER) evaluation by the directly error-counting approach and the computational approach at the channel output in simulation. 相似文献
45.
46.
The use of bulky ligands in the rhodium-catalyzed reaction of aldehydes 7 (R1 = Ph) and 18 with 1-octyne increased the selectivity for ketones 13 and 20, to the detriment of ketones 12 and 19. Bulky phosphines reduced the hydroacylation reaction rate, leading to competition from the addition of the benzoic acid co-catalyst to the alkynes. This competing reaction can be suppressed by using the clay Montmorillonite K 10 (MK-10) as the co-catalyst instead of benzoic acid. 相似文献
47.
48.
We study Poincaré duality algebras over the field F2 of two elements. After introducing a connected sum operation for such algebras we compute the corresponding Grothendieck group of surface algebras (i.e., Poincaré algebras of formal dimension 2). We show that the corresponding group for 3-folds (i.e., algebras of formal dimension 3) is not finitely generated, but does have a Krull-Schmidt property.We then examine the isomorphism classes of 3-folds with at most three generators of degree 3, provide a complete classification, settle which such occur as the cohomology of a smooth 3-manifold, and list separating invariants.The closing section and Appendix A provide several different means of constructing connected sum indecomposable 3-folds. 相似文献
49.
Hanspeter Schmidli 《Insurance: Mathematics and Economics》2010,46(1):3-11
We consider several models for the surplus of an insurance company mainly under some light-tail assumptions. We are interested in the expected discounted penalty at ruin. By a change of measure we remove the discounting, which simplifies the expression. This leads to (defective) renewal equations as they had been found by different methods in the literature. If we use the change of measure such that ruin becomes certain, the renewal equations simplify to ordinary renewal equations. This helps to discuss the asymptotics as the initial capital goes to infinity. For phase-type claim sizes, explicit formulae can be derived. 相似文献
50.
We propose a couple of general ways of constructing authentication schemes from actions of a semigroup on a set, without exploiting any specific algebraic properties of the set acted upon. Then we give several concrete realizations of this general idea, and in particular, we describe several authentication schemes with long-term private keys where forgery (a.k.a. impersonation) is NP-hard. Computationally hard problems that can be employed in these realizations include the Graph Colorability problem, the Diophantine problem, and many others. 相似文献