Reactive ketimino radical acceptors: intermolecular alkyl radical addition to imines with a phenolic hydroxyl group

Intermolecular carbon radical addition to the carbon-nitrogen double bond of ketimines was studied. In the study on the reactivity of various aldimines, we found that the aldimine 7 having a phenolic hydroxyl group shows an excellent reactivity toward nucleophilic carbon radicals. A remarkable effect of phenolic hydroxyl group is assumed to be the stabilization of intermediate aminyl radical provided by a hydroxyl group. The screening of reactive ketimino acceptors showed that ketimines 15, 17, and 19 having a phenolic hydroxyl group exhibit excellent reactivities. The radical addition to ketimines 15, 17, and 19 took place regioselectively at the imino carbon to give the C-alkylated products without the formation of N-alkylated products. Enantioselective ethyl radical addition to ketimine 15 using chiral box ligand and Zn(OTf)2 gave the diethylated product 30 in 80% ee.     

A kinetic parameter concerning mass transfer in silica monolithic and particulate stationary phases measured by the peak-parking and slow-elution methods

Mass transfer in monolithic C18-silica stationary phases and C18-silica gel particles was studied. A traditional kinetic parameter, gamma(s)D(s), which is a diffusion coefficient of solute molecules in the stationary phase, was measured by two unusual approaches, i.e., peak-parking and slow-elution methods. The correlation between the ratio of gamma(s)D(s) to molecular diffusivity (Dm) and the retention factor (k) was represented by one common curve, irrespective of the RPLC conditions. A similar curved profile was also observed between another kinetic parameter (D(Ls)), which is related to the axial diffusive molecular migration in the stationary phase, and the retention equilibrium constant (Ka). The values of D(Ls) and Ka were calculated from those of gamma(s)D(s) and k, respectively. The ratio of D(Ls)/Dm increases with decreasing Ka and seems to approach around unity when Ka is infinitely small. The dependence of D(Ls) on Ka was also studied from extra-thermodynamic points of view. The linear correlation between In D(Ls) and In Ka suggests the existence of a kind of linear free energy relationship between the mass transfer in the stationary phase and the retention equilibrium. Because these characteristics of D(Ls) are similar to those of the surface diffusion coefficient (D(sur)), D(Ls) seems to correspond to D(sur).     

Upper limit on gravitational wave backgrounds at 0.2 Hz with a torsion-bar antenna

We present the first upper limit on gravitational wave (GW) backgrounds at an unexplored frequency of 0.2 Hz using a torsion-bar antenna (TOBA). A TOBA was proposed to search for low-frequency GWs. We have developed a small-scaled TOBA and successfully found Ω(gw)(f)<4.3×10(17) at 0.2 Hz as demonstration of the TOBA's capabilities, where Ω(gw)(f) is the GW energy density per logarithmic frequency interval in units of the closure density. Our result is the first nonintegrated limit to bridge the gap between the LIGO band (around 100 Hz) and the Cassini band (10(-6)-10(-4) Hz).     

Transition of chaotic motion to a limit cycle by intervention of economic policy: an empirical analysis in agriculture

This paper investigates the transition of dynamics observed in an actual real agricultural economic dataset. Lyapunov spectrum analysis is conducted on the data to distinguish deterministic chaos and the limit cycle. Chaotic and periodic oscillation were identified before and after the second oil crisis, respectively. The statitonarity of the time series is investigated using recurrence plots. This shows that government intervention might reduce market instability by removing a chaotic market's long-term unpredictability.     

Experimental Investigations of Discrepancies in Three-Nucleon Reactions

Experiments on pd scattering, pd capture and pd breakup performed by our Kyushu University group since 1988 are reviewed. Various discrepancies between the experimental results and 3N Faddeev calculations have been found, and systematical measurements of the discrepancies have been made. From discrepancies in pd scattering cross section and in 3N binding energy, 2π-exchange 3N force was determined, and the discrepancies were satisfactorily diminished. There are, however, still many discrepancies awaiting theoretical investigation, as described in this report.     

Atomic resolution STM observation of the Bi---O surface of yttrium substituted Bi2Sr2CaCu2Oy single crystals

We first examined Bi---O surfaces of Bi₂Sr₂CaCu₂O_y single crystals, whose Ca sites were substituted by Y ions, using an ultra-high vacuum scanning tunneling microscope (UHV-STM). Atomic resolution surface images were obtained for both the unsubstituted superconducting crystals and non-superconducting crystals, whose 60% Ca sites were substituted by Y ions. We found a lot of unperiodic disorder in the surface structure of the Y substituted crystal. The disorder seems to be caused by the random distribution of the Y ions.     

Recent Few-Nucleon Experiments and Discrepancies to be Solved

After ππ-exchange three-nucleon force (ππ3NF) was found in 1998, many experiments were made on 3N reactions and discrepancies between experiments and calculations with ππ3NF were reported. Origins of these remaining discrepancies have not been found yet. We briefly review experiments and the discrepancies in Nd scattering, Nd breakup and pd capture at intermediate energy, and review also recent systematic investigation on Space-Star anomaly and Quasi-Free Scattering anomaly in pd breakup at low energy.