Adsorption and luminescence properties of Tb3+-modified perfluorosulfonic acid membrane

After treatment of perfluorosulfonic acid membrane MF-4SK with an aqueous solution of TbCl₃, the protons in sulfo groups are completely replaced by the hydrated terbium cations. Specific features of the water adsorption and its influence on the luminescence of the modified membrane were examined.     

Polyimide-polysiloxane-segmented copolymers as high-temperature polymer electrolytes

Based on the fact that the flexibility of the polymer backbone will affect the ion transport and sometimes enhance the ionic conductivity, copolymer electrolytes of 1,2,4,5-benzene-tetracarboxylic dianhydride (PMDA), 4-aminophenyl ether (ODA), and aminopropyldimethyl-terminated polydimethylsiloxane (PSX), with or without doping of lithium triflate, have been prepared and investigated by infrared spectroscopy and electrical conductivity measurements. The PSX was found to be incorporated into PMDA-ODA polyimide to form block copolymers, and the best conductivity (10^-7 s/cm at 300°C) is observed in the lithium triflate-doped PMDA-ODA-PSX copolymer with a composition of 4PMDA: 3DA: 0.6PSX: 2LiCF₃SO₃. This conductivity is about 100 times better than the result of the lithium-doped PMDA, ODA, and 2,5-diaminobenzene sulfonic acid (DABSA) copolymer (4PMDA: 3DA:1DABSA:1LiCF₃SO₃) recently reported by this group. © 1994 John Wiley & Sons, Inc.     

Theg B*Bϱ andg D*Dϱ coupling constants in QCD

Theg _B*B? andg _D*D? coupling constants are calculated at the intermediate momentum transfer interval 0.5 GeV²≤Q ²≤1.5 GeV², in the context of QCD sum rules. Our predictions are in good agreement with those of the Vector Dominance Model     

Stereoselective hydrogenation of acetylene on copper catalysts: A quantum-chemical study

The structure of the alkyne adsorption complex on the copper surface is favorable for the stereoselective formation of cis isomers in the hydrogenation reaction. The pathway of dissociative hydrogen adsorption on copper is reported. It is assumed that the electron-donating promoter acts to reduce the electron work function of the copper catalyst by partially covering or “decorating” the surface of the copper particles.     

An algebraic extension of the MacMahon Master Theorem

We present a new algebraic extension of the classical MacMahon Master Theorem. The basis of our extension is the Koszul duality for non-quadratic algebras defined by Berger. Combinatorial implications are also discussed.

     

Straight and Modified Copper Catalysts for Stereoselective Hydrogenation of 5,17-Docosadiyne

Modified copper catalysts providing high rate of 5,17-docosadiyne hydrogenation with 100% yield of cis,cis-5,17-docosadiene (gypsy moth attractant) were developed.     

Efficient synthesis of arylsulfamides by reaction of amines with arylsulfamoyl imidazolium triflate

Arylsulfamoyl imidazolium triflates, readily prepared from the corresponding chlorides, react with amines under neutral conditions to form arylsulfamides in high yields. This methodology, which contrasts with the slow and inefficient reactions of amines with arylsulfamoyl chlorides, is applied to the synthesis of arylsulfamide 3a, a bioisotere of muraglitazar.     

Centrality dependence of charged hadron transverse momentum spectra in Au+Au collisions from sqrt[s(NN)]=62.4 to 200 GeV

We have measured transverse momentum distributions of charged hadrons produced in Au+Au collisions at sqrt[s(NN)]=62.4 GeV. The spectra are presented for transverse momenta 0.25相似文献