Selenium Catalyzed Synthesis of Cyclic Thionecarbamates from Hydroxyisocyanides and Sulfur

Abstracts

1,3-Oxazine-2-thiones were prepared from 3-hydroxyisocyanides and sulfur in the presence of catalytic amounts of selenium.     

A Double Tiling of Triangles and Regular Hexagons

A tiling of triangles and regular hexagons, which wraps around a focal point and covers the plane twice, is investigated using both synthetic triangle geometry and complex numbers. Received February 12, 1999, and in revised form October 25, 1999. Online publication May 16, 2000.     

Theoretical calculations of magnetic properties of the α-, β-, γ- and δ-phases of p-NPNN

Hybrid density functional theory (HDFT) calculations have been carried out for clusters of p-NPNN extracted from the experimental crystal structures of the α-, β-, γ- and δ-phases in order to investigate the weak magnetic interactions between the organic radicals theoretically. From the systematic HDFT calculations for β- and γ-phase p-NPNN clusters, it was found that the magnetic long-range ferromagnetic and antiferromagnetic orderings would be presented in the β- and γ-phase p-NPNN crystals, respectively.     

Certain CR submanifolds of maximal CR dimension of complex space forms

We study m-dimensional real submanifolds with (m−1)-dimensional maximal holomorphic tangent subspace in complex space forms. On such a manifold there exists an almost contact structure which is naturally induced from the ambient space and in this paper we study the anti-commutative condition of the almost contact structure and the second fundamental form of these submanifolds and we characterize certain model spaces in complex space forms.     

Chow rings of excellent quadrics

In this paper we compute the multiplicative structure of the Chow ring of an excellent anisotropic quadric by using the algebraic cobordism theory.     

Confirmation/Observation of Hindered E2 Strengths in-16,18C

The lifetime of the first excited 2~+ state in ~(18)C was measured using an upgraded recoil shadow method to determine the electric quadrupole transition.The measured mean lifetime is 18.9±0.9 (stat)±4.4 (syst) ps,which corresponds to a B(E2;2~+_1→0~+_(gs)) value of (4.3±0.2±1.0) e~2fm~4,or about 1.5 Weisskopf units.The mean lifetime of the first 2~+ state in ~(16)C was remeasured to be about 18 ps,about four times shorter than the value reported previously.This discrepancy was explained by incorporating the γ-ray angular distribution measured in this work into the previous measurement.The observed transition strengths in ~(16,18)C are hindered compared to the empirical transition strengths,indicating that the anomalous hindrance observed in ~(16)C persists in ~(18)C.     

On a moving liquid film and its instability on textured surfaces

Recently, two regimes of viscous friction on textured surfaces were proposed in the context of penetration of liquid film into the texture (EPL 79, 56005 (2007)): the Poiseuille and Stokes regimes. With this idea on viscous friction, we theoretically discuss instabilities on a liquid film on textured surfaces when the film is forced to move with external forces. When a film recedes due to a pressure drop, we find scaling laws for instabilities to be checked in future experiments. When a circular film expands due to centrifugal force we find that the expanding film is stable against rim fluctuations (within the linear stability analysis) with its radius determined by a simple equation. Our discussion sheds light on the curvature of the front of the moving liquid film on textured surfaces and how the film thickness is kept fixed to the texture height on textured surfaces, aspects which have not been discussed in previous studies.     

Monomer-Dimer Equilibrium of Rhodamine B Encapsulated in Si–Al and Si–Ti Binary-Oxide Thin Films

Si—Al and Si—Ti binary-oxide thin films including Rhodamine B (RB) have been prepared. They were dip-coated as a function of time after mixing of each sol-gel reaction system. The absorption and fluorescence spectra of the individual films have been observed. These spectra were analyzed in order to clarify the behavior of RB along with the change in the environment around the RB molecules, caused by the progress of the sol-gel reaction, in the fluid sol and the prepared thin films. Some amount of the RB dimers (H- and J-types) were formed in the Si—Al and Si—Ti binary-oxide films (Si : M = 75 : 25) prepared at the initial stage of the sol-gel reaction and aged under relative humidity of 60%. In the case of Si—Al binary-oxide films, the amount of the J-dimer decreased along with the reaction time at which the films were prepared, indicating that growing polymer networks of metal alkoxides around the RB molecules prevent the formation of the J-dimer. On the other hand, larger amounts of the H- and J-dimers were formed in the Si—Ti binary-oxide films prepared at longer reaction time of the solution. RB interacts more strongly with —TiOH compared with —AlOH. In the case of the Si—Ti binary-oxide films, with the progress of the sol-gel reaction, RB molecules in the prepared films easily cohere around the —TiOH and form the dimers because of increase in the amount of the —TiOH and contraction in the volume of the spaces where RB molecules exist.