Towards the synthesis of sulfonamide-based RNA mimetics

The scalable, divergent synthesis of all four monomers required for the preparation of sulfonamide-based RNA mimetics is described. Such mimetics may combine excellent mimicry of the parent RNA with enhanced (bio)chemical robustness and convenient oligomerization. As a proof of principle, a dimer resulting from the monomers is described.     

光学仿真分析在光电传感器开发过程中的应用

1 引言 光电传感器是指利用光电效应作为传感原理的传感器件,它主要由光源、光学通路、光电探测器等部分.光源发出的光照射到待检测的目标物体上,被目标物体调制后被光电探测器所接收.     

Synthesis and palladium-catalysed isomerisation of fused polycyclic tetrahydrofurans: efficient and stereoselective one-pot domino construction of functionalised bridged bicyclo[n.2.1] ring systems

A new one-pot domino reaction for a general entry to functionalised bridged bicyclo[n.2.1] ring systems from α ,α’-diactivated cyclic ketones and trans-1,4-dihalides is described. The sequence combines a base promoted C–O cycloalkylation reaction leading to fused polycyclic enol ethers and their in situ palladium-catalysed isomerisation.     

Highly Axial Magnetic Anisotropy in a N3O5 Dysprosium(III) Coordination Environment Generated by a Merocyanine Ligand

A spiropyran‐based switchable ligand isomerizes upon reaction with lanthanide(III) precursors to generate complexes with an unusual N₃O₅ coordination sphere. The air‐stable dysprosium(III) complex shows a hysteresis loop at 2 K and a very strong axial magnetic anisotropy generated by the merocyanine phenolate donor.     

Krull dimension of the enveloping algebra of a semisimple Lie algebra

Let be a complex semisimple Lie algebra and be its enveloping algebra. We deduce from the work of R. Bezrukavnikov, A. Braverman and L. Positselskii that the Krull-Gabriel-Rentschler dimension of is equal to the dimension of a Borel subalgebra of .

     

Gaussian estimates and L p -boundedness of Riesz means

We show that suitable upper estimates of the heat kernel are sufficient to imply the L ^p boundedness of several families of operators associated with the Schr?dinger group in various situations. This generalizes results by Sj?strand and others in the Euclidean case, and by Alexopoulos in the case of Lie groups and Riemannian manifolds. RID="*" ID="*"Research partially supported by the European Commission (European TMR Network "Harmonic Analysis" 1998-2001, Contract ERBFMRX-CT97-0159).