Oxidation of 3-carene by thallium(III) acetate

Oxidation of 3-carene by thallium(III) acetate leads to 3-acetyl-6,6-dimethylbicyclo[3.1.0]hexane; 2-(p-tolyl)-2-propanol; 3 /gb,4 /gb-caranediol, 1-(p-menthene)-5,8-diol, and a product with an assumed structure of 1-methyl-4-(α-hydroxyisopropyl)bicyclo[3.1.0]hexane-2-cis-cl. © 1983 Plenum Publishing Corporation

PMR study of the three-dimensional structure of stereoisomeric adducts of cis-alloocimene with acrylonitrile and their cyclization products with dichlorocarbene

1. cis-Alloocimene adds acrylonitrile to give two stereoisomeric adducts, which exist in a half-chair conformation. Based on PMR spectra, one of the stereoisomers has a quasiaxial methyl group and pseudoequatorial nitrile and isopropylidene groups, while the other stereoisomer has a quasi-axial isopropylidene substituent and equatorial nitrile and methyl groups. 2. Dichlorocyclopropanation of these adducts occurs from the sterically less hindered side of the molecules, with the formation, from one of the stereoisomers, of a cycloaddition product at the exocyclic double bond, and two stereoisomeric cycloaddition products at the two double bonds with a cis orientation of the cyclopropane ring and the CN group; the other stereoisomer, on the other hand, gives two stereoisomeric cycloaddition products at the two double bonds with a trans orientation of the cyclopropane ring and CN-group. © 1988 Plenum Publishing Corporation

Black Sea coastal forecasting system

The Black Sea coastal nowcasting and forecasting system was built within the framework of EU FP6 ECOOP (European COastalshelf sea OPerational observing and forecasting system) project for five regions: the south-western basin along the coasts of Bulgaria and Turkey, the north-western shelf along the Romanian and Ukrainian coasts, coastal zone around of the Crimea peninsula, the north-eastern Russian coastal zone and the coastal zone of Georgia. The system operates in the real-time mode during the ECOOP project and afterwards. The forecasts include temperature, salinity and current velocity fields. Ecosystem model operates in the off-line mode near the Crimea coast

Oxidation of carene by thallium(III) acetate

2-p-Tolylpropanol-2, p-menth-1,8-dien-3-ol, p-menth-1-en-3α, 8-diol, p-menth-1-en-3β, 8-diol, p-menth-1-en-3-on-8-ol, p-menth-1,8-dien-5,6-diol, and 2,3-dihydroxy-1,8-cineole are formed during the oxidation of 2-carene by thallium (III) acetate. © 1984 Plenum Publishing Corporation

On the low-temperature lattice thermal transport in nanowires

We propose a theory of low temperature thermal transport in nano-wires in the regime where a competition between phonon and flexural modes governs the relaxation processes. Starting with the standard kinetic equations for two different types of quasiparticles we derive a general expression for the coefficient of thermal conductivity. The underlying physics of thermal conductance is completely determined by the corresponding relaxation times, which can be calculated directly for any dispersion of quasiparticles depending on the size of a system. We show that if the considered relaxation mechanism is dominant, then at small wire diameters the temperature dependence of thermal conductivity experiences a crossover from $T^{1/2}$ to $T^3$-dependence. Quantitative analysis shows reasonable agreement with resent experimental results.Comment: 12 pages, 3 eps figure

Convergence of measures on compactifications of locally symmetric spaces

We conjecture that the set of homogeneous probability measures on the maximal Satake compactification of an arithmetic locally symmetric space S=Γ∖G/K is compact. More precisely, given a sequence of homogeneous probability measures on S, we expect that any weak limit is homogeneous with support contained in precisely one of the boundary components (including S itself). We introduce several tools to study this conjecture and we prove it in a number of cases, including when G=SL3(R) and Γ=SL3(Z)

Pb0.4Bi1.6Sr2Ca1Cu2O8+xPb_{0.4}Bi_{1.6}Sr_{2}Ca_{1}Cu_{2}O_{8+x} and Oxygen Stoichiometry: Structure, Resistivity, Fermi Surface Topology and Normal State Properties

$Pb_{0.4}Bi_{1.6}Sr_2CaCu_2O_{8+x}$ ($Bi(Pb)-$2212) single crystal samples were studied using transmission electron microscopy (TEM), $ab-$plane ($\rho_{ab}$) and $c-$axis ($\rho_c$) resistivity, and high resolution angle-resolved ultraviolet photoemission spectroscopy (ARUPS). TEM reveals that the modulation in the $b-$axis for $Pb(0.4)-$doped $Bi(Pb)-$2212 is dominantly of $Pb-$type that is not sensitive to the oxygen content of the system, and the system clearly shows a structure of orthorhombic symmetry. Oxygen annealed samples exhibit a much lower $c-$axis resistivity and a resistivity minimum at $80-130$K. He-annealed samples exhibit a much higher $c-$axis resistivity and $d\rho_c/dT<0$ behavior below 300K. The Fermi surface (FS) of oxygen annealed $Bi(Pb)-$2212 mapped out by ARUPS has a pocket in the FS around the $\bar{M}$ point and exhibits orthorhombic symmetry. There are flat, parallel sections of the FS, about 60\% of the maximum possible along $k_x = k_y$, and about 30\% along $k_x = - k_y$. The wavevectors connecting the flat sections are about $0.72(\pi, \pi)$ along $k_x = k_y$, and about $0.80(\pi, \pi)$ along $k_x = - k_y$, rather than $(\pi,\pi)$. The symmetry of the near-Fermi-energy dispersing states in the normal state changes between oxygen-annealed and He-annealed samples.Comment: APS_REVTEX 3.0, 49 pages, including 11 figures, available upon request. Submitted to Phys. Rev. B

INTERLAYER COUPLING AND THE METAL-INSULATOR TRANSITION IN Pr-SUBSTITUTED Bi(2)Sr(2)CaCu(2)O(8+y)

Substitution of rare-earth ions for Ca in Bi2Sr2CaCu2O8+y is known to cause a metal-insulator transition. Using resonant photoemission we study how this chemical substitution affects the electronic structure of the material. For the partial Cu-density of states at E_F and in the region of the valence band we observe no significant difference between a pure superconducting sample and an insulating sample with 60% Pr for Ca. This suggests that the states responsible for superconductivity are predomi- nately O-states. The partial Pr-4f density of states was extracted utilizing the Super- Koster-Kronig Pr 4d-4f resonance. It consists of a single peak at 1.36eV binding energy. The peak shows a strongly assymetric Doniach-Sunjic line- shape indicating the presence of a continuum of electronic states with sharp cut off at E_F even in this insulating sample. This finding excludes a bandgap in the insulating sample and supports the existance of a mobility gap caused by spatial localization of the carriers. The presence of such carriers at the Pr-site, between the CuO_2 planes shows that the electronic structure is not purely 2-dimensional but that there is a finite interlayer coupling. The resonance enhancement of the photoemission cross section, at the Pr-4d threshold, was studied for the Pr-4f and for Cu-states. Both the Pr-4f and the Cu-states show a Fano-like resonance. This resonance of Cu-states with Pr-states is another indication of coupling between the the Pr-states and those in the CuO_2 plane. Because of the statistical distribution of the Pr-ions this coupling leads to a non-periodic potential for the states in the CuO_2 plane which can lead to localization and thus to the observed metal-insulator transition.Comment: Gziped uuencoded postscript file including 7 figures Scheduled for publication in Physical Review B, May 1, 1995

Spin flipping a stored vertically polarized proton beam with an RF solenoid

A recent experiment in the IUCF cooler ring studied the spin flip of a stored vertically polarized 139 MeV proton beam. This spin flip was accomplished by using an RF solenoid to induce an artificial depolarizing resonance in the ring, and then varying the solenoid’s frequency through this resonance value to induce spin flip. We found a polarization loss after multiple spin flips of about 0.00±0.05% per flip and also losses for very long flip times. This device will be useful for reducing systematic errors in polarized beam‐internal target scattering asymmetry experiments by enabling experimenters to perform frequent beam polarization reversals in the course of the experiment. © 1995 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87478/2/118_1.pd

First test of a partial Siberian snake for acceleration of polarized protons

We recently studied the first acceleration of a spin‐polarized proton beam through a depolarizing resonance using a partial Siberian snake. We accelerated polarized protons from 95 to 140 MeV with a constant 10% partial Siberian snake obtained using rampable solenoids. The 10% partial snake suppressed all observable depolarization during acceleration due to the Gγ=2 imperfection depolarizing resonance which occurred near 108 MeV. However, 20% and 30% partial Siberian snakes apparently moved an intrinsic depolarizing resonance, normally near 177 MeV, into our energy range; this caused some interesting, although not‐yet‐fully understood, depolarization. © 1995 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87483/2/85_1.pd