In Process Citation

The electrochemical oxidation of khelline and amikhelline (chromone derivatives) has been performed by cyclic voltammetry at carbon-paste and polymeric carbon electrodes. The mechanism of oxidation of the two compounds at various pH values has been deduced. The detection limit is 8 x 10(-7)M. A constant-current coulometrie procedure is also described, based on the oxidation of the two chromones with vanadium(V) and backtitration of the excess of oxidant with iron(II).     

The enumeration of extreme rigid honeycombs

Journal of Algebraic Combinatorics - Rigid honeycombs were introduced by Knutson et al. (J Am Math Soc 17:19–48, 2004), and they were shown in Bercovici et al. (J Funct Anal...     

Complexation de l'argent(I) par des teramines cycliques

Complexation of Silver(I) by Cyclic Tetramines The nature of Ag(I)-complexes with 1,4,8,11-tetraazacyclotetradecane ( 1 ), 1,5,9,13-tetraazacyclohexadecane ( 2 ) 1,5,10,14-tetraazacyclooctadencane ( 3 ) and 1,6,11,16-tetraazacycloeicosane ( 4 ) is studied. The effect of ring size on disproportionation of the Ag() cation in the presence of ligand is reported. The stability of Ag(I)-complexes with 3 and 4 in aqueous solution is determined by means of potentiometric titration.     

金刚石车削表面微纳织构的气囊抛光改进

单点金刚石车削技术被广泛应用于光学表面的超精密加工。然而,车削表面固有的周期性残留刀痕结构将增强表面散射效应,恶化元件光学性能。为了抑制散射以获得高质量光学表面,采用气囊抛光技术主动改变车削表面周期性刀痕结构。基于Taguchi正交试验,以表面粗糙度及功率谱密度的改善率为设计指标,分析获得了最优抛光参数。采用该最优参数对一精车表面进行了抛光试验,抛光后表面粗糙度Ra由3.81 nm降到1.42 nm,各空间频率功率谱密度大幅降低,同时表面的衍射条纹消失。试验结果验证了所采用的抛光及相应优化方法的有效性,具有重要的工程应用价值。     

Lipid-lowering effects of ethyl 2-phenacyl-3-aryl-1H-pyrrole- 4-carboxylates in rodents

A series of substituted 2-phenacyl-3-phenyl-1H-pyrrole-4-carboxylates were prepared from substituted acetophenones in 6 steps. The final condensations between a chloroenal and an aminoketone were carried out under neutral conditions in parallel to yield the series listed below. Selected pyrrole derivatives proved to be potent hypolipidemic agents lowering serum triglyceride concentrations in CF-1 male mice after 14 days of I.P. administration. One agent orally lowered serum cholesterol in Sprague-Dawley male rats at 2mg/kg/day after 14 days. The agents demonstrated a lowering of mouse serum LDL- cholesterol levels and selected compounds showed an elevation of serum HDL-cholesterol levels. The cholesterol concentrations in the liver were raised while the cholesterol and triglyceride contents of the aorta were significantly lowered by the selected trisubstituted pyrrole.     

The first example of a hetero-tetranuclear [(VO)Gd](2) complex: synthesis, crystal structure and magnetic properties of [VOLGd(hfa)(2)CH(3)OH](2).2CH(3)OH.2(CH(3))(2)CO

A cyclic tetranuclear [V(IV)O-Gd(III)](2) complex with VO and Gd ions alternately arrayed, behaves, from the magnetic point of view, as two independent dinuclear entities each having a S= 4 ground state, as a consequence of an active and ferromagnetic VO-Gd interaction through the double phenoxo bridge and a magnetically inactive VO-Gd interaction through the amide bridge.     

Analysis of materials selected for multilayer diffractive optical elements

An analysis model to optimize the materials selected for multilayer diffractive elements (MLDOEs) is presented with approximate Cauchy dispersion formula of refractive index and the maximum polychromatic integral diffraction efficiency (PIDE). The analysis model presents that the maximum PIDE of MLDOEs consisting of two materials with large Abbe number difference and small partial dispersion difference can be generated. The scope of application and the relationship between diffraction efficiencies of MLDOEs with different material pairs and different design wavelength pairs are presented and simulated with the analysis model of MLDOEs.     

Eigenvalue inequalities in an embeddable factor

We provide a characterization of the possible eigenvalues of the sum of two selfadjoint elements of a II factor which can be embedded in the ultrapower of the hyperfinite II factor.

     

Normal boundary dilations and rationally invariant subspaces

The first named author was supported by grants from the National Science Foundation.