A Remarkably Stable and Simple Monocyclic Thiepin. Synthesis and Properties of 2, 7-Di-tert-butyl-4-ethoxycarbonyl-5-methylthiepin

A simple monocyclic 8n electron thiepin, 2,7-di-tert-butyl-4- -ethoxycarbonyl-5-methylthiepin (13) stabilized by two bulky tert- -butyl groups at 2- and 7-positions, was synthesized from 2,6-di- -tert-butyl-4-methylthiopyrylium tetrafluoroborate (11). In spite of of its monocyclic thiepin structure, the compound 13 showed remarkable thermal stability and had a half-life of 7.1 h at 130 °C. Judging from the 1H-NMR spectrum, the thiepin 13 is considered to be an atropic molecule. Synthetic details of 11 and 13, and the chemical and physical properties of 13 are also described

A Remarkably Stable and Simple Monocyclic Thiepin. Synthesis and Properties of 2, 7-Di-tert-butyl-4-ethoxycarbonyl-5-methylthiepin

A simple monocyclic 8n electron thiepin, 2,7-di-tert-butyl-4- -ethoxycarbonyl-5-methylthiepin (13) stabilized by two bulky tert- -butyl groups at 2- and 7-positions, was synthesized from 2,6-di- -tert-butyl-4-methylthiopyrylium tetrafluoroborate (11). In spite of of its monocyclic thiepin structure, the compound 13 showed remarkable thermal stability and had a half-life of 7.1 h at 130 °C. Judging from the 1H-NMR spectrum, the thiepin 13 is considered to be an atropic molecule. Synthetic details of 11 and 13, and the chemical and physical properties of 13 are also described

Snowden's revelations and the attitudes of students at Swedish universities

Purpose – Mapping of Swedish students' attitudes toward Snowden's revelations and their effects in the political and socio-cultural environment of Sweden. Design/methodology/approach – A questionnaire was answered by 190 Swedish University students. The quantitative responses to the survey were statistically analysed as well as qualitative considerations of free text answers. Findings – Swedish students had a high level of knowledge of Snowden revelations, they actively searched for information, they gave a positive judgement of Snowden's actions and they were willing to follow his example in Sweden but not the US. They trusted their country and most of its institutions and authorities except for secret service agencies and Internet and computer software companies. Practical implications – Design of education for university students, especially in Information Technology programs. Social implications – Developing and applying policies on privacy, surveillance and whistleblowing. Originality/value – This study is part of a bigger international study to map students' attitudes toward Snowden's revelations and their opinions about privacy, surveillance and whistleblowing opening up for cross-cultural analyses. This record was migrated from the OpenDepot repository service in June, 2017 before shutting down

Structure of the Fulde-Ferrell-Larkin-Ovchinnikov state in two-dimensional superconductors

Nonuniform superconducting state due to strong spin magnetism is studied in two-dimensional type-II superconductors near the second order phase transition line between the normal and the superconducting states. The optimum spatial structure of the orderparameter is examined in systems with cylindrical symmetric Fermi surfaces. It is found that states with two-dimensional structures have lower free energies than the traditional one-dimensional solutions, at low temperatures and high magnetic fields. For s-wave pairing, triangular, square, hexagonal states are favored depending on the temperature, while square states are favored at low temperatures for d-wave pairing. In these states, orderparameters have two-dimensional structures such as square and triangular lattices.Comment: 11 pages (LaTeX, revtex.sty), 3 figures; added reference

Anomalous In-Plane Anisotropy of the Onset of Superconductivity in (TMTSF)2ClO4

We report the magnetic field-amplitude and field-angle dependence of the superconducting onset temperature Tc_onset of the organic superconductor (TMTSF)2ClO4 in magnetic fields H accurately aligned to the conductive ab' plane. We revealed that the rapid increase of the onset fields at low temperatures occurs both for H // b' and H // a, irrespective of the carrier confinement. Moreover, in the vicinity of the Pauli limiting field, we report a shift of a principal axis of the in-plane field-angle dependence of Tc_onset away from the b' axis. This feature may be related to an occurrence of Fulde-Ferrell-Larkin-Ovchinnikov phases.Comment: 4 pages, 4 figure

On a q-difference Painlev\'e III equation: II. Rational solutions

Rational solutions for a $q$-difference analogue of the Painlev\'e III equation are considered. A Determinant formula of Jacobi-Trudi type for the solutions is constructed.Comment: Archive version is already official. Published by JNMP at http://www.sm.luth.se/math/JNMP

Initial wave packets and the various power-law decreases of scattered wave packets at long times

The long time behavior of scattered wave packets $\psi (x,t)$ from a finite-range potential is investigated, by assuming $\psi (x,t)$ to be initially located outside the potential. It is then shown that $\psi (x,t)$ can asymptotically decrease in the various power laws at long time, according to its initial characteristics at small momentum. As an application, we consider the square-barrier potential system and demonstrate that $\psi (x,t)$ exhibits the asymptotic behavior $t^{-3/2}$, while another behavior like $t^{-5/2}$ can also appear for another $\psi (x,t)$.Comment: 5 pages, 1 figur

Phase Diagram of Pressure-Induced Superconductivity in EuFe2As2 Probed by High-Pressure Resistivity up to 3.2 GPa

We have constructed a pressure$-$temperature ($P-T$) phase diagram of $P$-induced superconductivity in EuFe$_2$As$_2$ single crystals, via resistivity ($\rho$) measurements up to 3.2 GPa. As hydrostatic pressure is applied, an antiferromagnetic (AF) transition attributed to the FeAs layers at $T_\mathrm{0}$ shifts to lower temperatures, and the corresponding resistive anomaly becomes undetectable for $P$ $\ge$ 2.5 GPa. This suggests that the critical pressure $P_\mathrm{c}$ where $T_\mathrm{0}$ becomes zero is about 2.5 GPa. We have found that the AF order of the Eu$^{2+}$ moments survives up to 3.2 GPa without significant changes in the AF ordering temperature $T_\mathrm{N}$. The superconducting (SC) ground state with a sharp transition to zero resistivity at $T_\mathrm{c}$ $\sim$ 30 K, indicative of bulk superconductivity, emerges in a pressure range from $P_\mathrm{c}$ $\sim$ 2.5 GPa to $\sim$ 3.0 GPa. At pressures close to but outside the SC phase, the $\rho(T)$ curve shows a partial SC transition (i.e., zero resistivity is not attained) followed by a reentrant-like hump at approximately $T_\mathrm{N}$ with decreasing temperature. When nonhydrostatic pressure with a uniaxial-like strain component is applied using a solid pressure medium, the partial superconductivity is continuously observed in a wide pressure range from 1.1 GPa to 3.2 GPa.Comment: 7 pages, 6 figures, accepted for publication in Physical Review B, selected as "Editors' Suggestion