Electroviscous Forces on a Charged Cylinder Moving Near a Charged Wall

The refined theory of the electroviscous lift forces is presented for the case when the separation distance between the particle and the wall is larger than the double-layer thickness. The theory is based on the lubrication approximation for motion of a long cylinder near a solid wall in creeping flow. The approximate analytical formula for the lift force valid for Pe相似文献   

The fluorescent oxidation products of dihydroxyphenylalanine and its esters

Dihydroxyphenylalanine (DOPA), its methyl ester (DOPAM) and the N-acetylated derivative of the ester (DOPAMNA) are found to undergo rapid oxidation in air-saturated alkaline solution. Some of the products of oxidation exhibit fluorescent emission in the 300-500 nm spectral range and their excitation-emission spectra have been determined in acidic and alkaline aqueous solutions. The spectral distributions and positions of the maxima depend on the pH of the solution. Excitation-emission maxima associated with the protonated phenolic form of the compounds occur at shorter wavelengths than those of the conjugate base. At some pH values the phenolic forms of these molecules are excited and undergo rapid deprotonation in the excited state; as a consequence, emission is observed from the phenolate anion. The fluorescence excitation-emission spectrum of an authentic sample of 3,4-dihydroxycinnamic (caffeic) acid has also been determined and features of the fluorescence spectra of the principal oxidation products are consistent with the presence of 3,4-hydroxycinnamoyl compounds in solutions of oxidized DOPAM and DOPAMNA.     

Perturbed Dolbeault operators and the homology Todd class

This paper discusses the role played by perturbed Dolbeault operators in relating the coherent sheaf and elliptic operator perspectives on the homology of projective varieties. Among the consequences are index formulas for perturbed Dolbeault operators.

     

A novel high-resolution interference spectrometer

A novel precision wavemeter is presented with a resolution of better than 0·01 nm. A Sagnac interferometer with two diffraction gratings forms the basis of the instrument. Using spatial heterodyning techniques and a CCD camera/frame grabber data acquisition system allows fast computer control and power spectrum analysis. The mode structure and mode hopping characteristics of a typical laser diode were examined as a function of diode injection current.     

Embeddings ofC(Δ) andL 1[0, 1] in Banach lattices

It is proved that ifE is a separable Banach lattice withE′ weakly sequentially complete,F is a Banach space andT:E→F is a bounded linear operator withT′F′ non-separable, then there is a subspaceG ofE, isomorphic toC(Δ), such thatT _G is an isomorphism, whereC(Δ) denotes the space of continuous real valued functions on the Cantor discontinuum. This generalizes an earlier result of the second-named author. A number of conditions are proved equivalent for a Banach latticeE to contain a subspace order isomorphic toC(Δ). Among them are the following:L ¹ is lattice isomorphic to a sublattice ofE′;C(Δ)′ is lattice isomorphic to a sublattice ofE′; E contains an order bounded sequence with no weak Cauchy subsequence;E has a separable closed sublatticeF such thatF′ does not have a weak order unit. The research of both authors was partially supported by the National Science Foundation, NSF Grant No MPS 71-02839 A04.     

Modeling Stochastic Dominance as Infinite-Dimensional Constraint Systems via the Strassen Theorem

We use the Strassen theorem to solve stochastic optimization problems with stochastic dominance constraints. First, we show that a dominance-constrained problem on general probability spaces can be expressed as an infinite-dimensional optimization problem with a convenient representation of the dominance constraints provided by the Strassen theorem. This result generalizes earlier work which was limited to finite probability spaces. Second, we derive optimality conditions and a duality theory to gain insight into this optimization problem. Finally, we present a computational scheme for constructing finite approximations along with a convergence rate analysis on the approximation quality.     

EPR-dosimetry with carious teeth

The effect of caries in EPR dosimetry of tooth enamel (in the dose range of 0–1 Gy) was investigated. The enamel of each tooth was divided into carious, non-carious and intermediate portions. The EPR signals of enamel at g = 2.0018 (dosimetric) and g = 2.0045 (native) were examined. The intensity of the dosimetric signal was the same for all three portions, while that of the native signal was higher for carious portions than for non-carious and intermediate portions. Reconstruction of the laboratory applied doses was done using all portions. Reasonable correlation between nominal and reconstructed doses was found in most cases. The effect of alkali treatment on the native and dosimetric signals of enamel was also tested. Reduction of the native signal intensity, particularly in the carious portions, was found to be the only significant effect. This resulted in a slight improvement in the accuracy of the reconstructed doses.