Fluorescence spectra and chemical species of fluorescein molecules adsorbed on a calcinated porous Vycor glass

Properties of fluorescence and the excitation spectra of fluorescein molecules adsorbed onto a calcinated (773 K) porous Vycor glass have been investigated as a function of the amount of adsorbed dye (the surface coverage, θ = 0.00051 and 0.0098). The fluorescence and fluorescence-excitation spectra of fluorescein adsorbed onto Vycor glass showed the spectrum only due to cation species at θ = 0.00051. On the other hand, the spectra observed at θ = 0.0098 suggested the presence of cation, anion, and dianion species on the surface of Vycor glass. These results indicated the existence of at least two different types of adsorption sites involving the Brønsted acid site on the surfaces of Vycor glass.     

Convergence of the Approximation Scheme to American Option Pricing via the Discrete Morse Semiflow

We consider the approximation scheme to the American call option via the discrete Morse semiflow, which is a minimizing scheme of a time semi-discretized variational functional. In this paper we obtain a rate of convergence of approximate solutions and the convergence of approximate free boundaries. We mainly apply the theory of variational inequalities and that of viscosity solutions to prove our results.     

Photochemische Reaktionen. 107. Mitteilung. Zur Photochemie offenkettiger 2,6-bzw. 2,7-Dien-Carbonylverbindungen

The Photochemistry of Open-Chained 2,6- or 2,7-Dien-Carbonyl Compounds On ¹n, π*-excitation (λ > 347 nm) citral (5) and the methyl ketone 10 isomerize to compounds A (7, 19) and B (6, 20) , whereas the phenyl ketone 11 changes into the isomer 24 of type E. Evidence is given that the conversions to A and B may arise from the ³n, π*-state of the 2,6-diene-carbonyl compounds. On ¹n, π*-excitation (λ = 254 nm) 5 and 10 yield the isomers A (7, 19) and D (18, 22) , but no products of type B. Furthermore, conversion of 10 to the isomer 21 of type C is observed. Selective ¹n, π*-excitation (λ = 254 nm) as well as selective ¹n, π*-excitation (λ > 347 nm) of the 2,7-diene-carbonyl compounds 12 and 13 give rise to isomerization to the compounds F (25, 28) , exclusively. The intramolecular [2 + 2]-photocycloadditions are shown to be triplet processes. UV.-irradiation (λ > 280 nm) of compounds F (25, 28) furnishes the isomeric products G (26, 29) which photoisomerize to oxetanes of type H (27, 30).     

Local liquid velocity measurements in air-water bubbly flow

Local measurements of axial liquid velocity were performed for vertical upward air-water bubbly flow in a 101.6-mm inner-diameter round pipe by using a laser Doppler anemometer (LDA) and a hot-film anemometer (HFA). The data reduction approaches for both the LDA and HFA are discussed in detail. A threshold scheme with the information of local void fraction and velocity distribution in single-phase flow was applied to the LDA to approximately discriminate liquid velocity signals from those of the bubble interface velocity. Furthermore, a formulation was given to account for the effect of the bubble relative velocity on the liquid in the front and wake regions of the bubbles. For the HFA, an amplitude threshold scheme and a slope criterion were used to extract liquid velocity information. To reduce the measurement uncertainty, the experiments were performed in flow conditions where the area-averaged void fraction was less than 20%. The experimental results showed satisfactory agreement between the liquid volumetric flow rates calculated by area integration of the local liquid velocity and void fraction measurements, and the measured value by a magnetic flow meter. Also, the area-averaged relative velocity between the gas and liquid phases obtained from the current measurements agreed well with previous research.     

Multi-period resource allocation for estimating project costs in competitive bidding

Central European Journal of Operations Research - In competitive bidding for project contracts, contractors estimate the cost of completing a project and then determine the bid price. Accordingly,...     

Finite Hilbert stability of (bi)canonical curves

We prove that a generic canonically or bicanonically embedded smooth curve has semistable mth Hilbert points for all m≥2. We also prove that a generic bicanonically embedded smooth curve has stable mth Hilbert points for all m≥3. In the canonical case, this is accomplished by proving finite Hilbert semistability of special singular curves with $\mathbb{G}_{m}$ -action, namely the canonically embedded balanced ribbon and the canonically embedded balanced double A _2k+1-curve. In the bicanonical case, we prove finite Hilbert stability of special hyperelliptic curves, namely Wiman curves. Finally, we give examples of canonically embedded smooth curves whose mth Hilbert points are non-semistable for low values of m, but become semistable past a definite threshold.     

Metal nanoslit lenses with polarization-selective design

We present comprehensive studies on thin diffraction lenses made of arrays of subwavelength, parallel nanoslits in a gold film. Such a nanoslit lens can operate either as a conventional convex or concave lens. The lenses can be designed to focus linearly polarized light with polarization either perpendicular (TM-lens) or parallel to the slits (TE-lens), while the orthogonal polarization diverges when passing through the lens. The designs of each lens are initially built on the dispersion relations for wave propagation through a parallel-plate waveguide. Both TM- and TE-lenses were realized experimentally, and full-wave numerical simulations fully support the experimental results.     

Multipole effects in non-Kramers doublet system PrMg3

We performed ultrasonic measurements on a single crystal of PrMg₃. The characteristic Curie-type softening was observed in temperature dependence of transverse mode (C₁₁-C₁₂)/2 below 8 K down to 0.8 K. This softening in PrMg₃ is caused by a non-Kramers Γ₃ doublet ground state having electric quadrupoles O_u and O_v and magnetic octupole T_xyz. The elastic constant (C₁₁-C₁₂)/2 shows a minimum at 25 K, which cannot be explained by the quadrupole susceptibility based on the crystal electric field (CEF) levels. However, considering higher order (l=4) multipole, namely electric hexadecapole, the minimum around 25 K was well reproduced. At lower temperatures, a shoulder anomaly in elastic constant being deviated from the Curie-type softening was observed around 100-800 mK in (C₁₁-C₁₂)/2. This anomaly is unaffected by magnetic fields up to 14 T.