Palladium-catalyzed stereospecific 1,4-hydrogen migration of cis-cyclohex-2-en-1,4-diol systems

It has been revealed that the generation of 2-cyclohexenones from cis-1,4-dihydroxycyclohexene derivatives under PdCl₂(PPh₃)₂-HCO₂NH₄ system takes place in an intramolecular pathway involving unprecedented mode of suprafacial 1,4-hydrogen migration across the 1,4-allylic centers.     

Optical-Optical Double Resonance Spectroscopy of the 1g(P1)-AΠ (1u)-XΣg Transition of I2

Optical-optical double resonance spectroscopy was used to study the 1_g(³P₁) ion-pair state of I₂ correlating to I⁻(¹S)+I⁺³P₁) at the dissociation limit. We gained access to the 1_g(³P₁) state though the A³Π (1_u) state in the (1+1) photon-excitation scheme. The pump laser excited the A³Π (1_u)-X¹Σ_g⁺ transition at a fixed frequency for state selection. The probe laser was scanned to detect the 1_g(³P₁)-A³Π (1_u) resonance by monitoring the ultraviolet emission from the 1_g(³P₁) state at 278 nm. The 1_g(³P₁) state was observed in a vibrational progression consisting of P and R doublets. An energy level analysis was carried out for the 1_g(³P₁) state in the 0≤ v ≤ 14 and 12≤J≤135 range, which led to a set of molecular parameters including the Ω-doubling constant. The Ω-doubling of the 1_g(³P₁) state was discussed by the pure precession model and interpreted to occur through the heterogeneous coupling with the 0_g⁻(³P₁) state correlating to the same ionic asymptote.     

Laser ablation synthesis of monodispersed magnetic alloy nanoparticles

Monodispersed CoPt alloy nanoparticles were synthesized by a pulsed laser ablation (PLA) technique coupled with a low-pressure operating differential mobility analyzer (LP-DMA). The CoPt alloy nanoparticles were generated by laser ablating a solid Co–Pt target. In CoPt alloy nanoparticles synthesized from a target with a Co composition of 75 at%, the nanoparticle surfaces were covered by an oxide layer and exhibited a core-shell structure. In contrast, no shell was observed in particles generated from a target with a Co:Pt ratio of 50:50 at%. According to an EDX analysis, the compositions of the individual nanoparticles were almost the same as that of the target material. Finally, the magnetic hysteresis loops of the CoPt alloy nanoparticles exhibited ferromagnetism.     

The development of efficient portfolios in Japan with particular emphasis on sales and earnings forecasting

In this study, we show that earnings forecasting creates an index-tracking portfolio that dominates the historical model trade-off curve. We find that using Toyo Keizai earnings forecasts improves geometric means by over 300 basis points compared to the historical model. Weighted latent root regression is used in this study to create portfolios that have outperformed the Japanese market in backtest and in real-time performance.     

Mössbauer Spectroscopic Study on Vertical Distribution of Iron Species in Sediments from Qinghai Lake,China

In this study, ⁵⁷Fe Mössbauer spectroscopy has been applied to sediments collected from Qinghai Lake in Qinghai Province, China, to investigate the vertical distribution of iron species. Their Mössbauer spectra consisted of four doublets ascribable to one paramagnetic high-spin Fe³⁺, two paramagnetic high-spin Fe²⁺ with different quadrupole splittings, and one diamagnetic low-spin Fe²⁺ that corresponds to pyrite (FeS₂). The distribution of pyrite suggested climatic changes during the past nine thousand years. It was demonstrated that the iron speciation in the salt lake sediments by Mössbauer spectroscopy can be used to reconstruct the past environment.

     

Thickness and Surface Profile Measurement by a Sinusoidal Wavelength-Scanning Interferometer

We propose a sinusoidal wavelength-scanning interferometer for measuring thickness and surface profile of a thin film. The interference signal contains phase modulation amplitude Z and phase $aL which are related to the positions and profiles of the reflecting surfaces, respectively. By reducing the difference between the detected signal and the estimated signal using the multidimensional nonlinear least-squares algorithm, we estimate values of Z and $aL. Experimental results show that the front and rear surfaces of a silica glass plate of 20 $mUm-thickness could be measured with an error less than 10 nm.     

A regioselective enolate formation of trimethylsilylmethyl ketones application to the (E)-selective synthesis of α,β-unsaturated ketones

Two possible enolate anions of trimethylsilylmethyl ketones have been prepared regioselectively by the appropriate choice of base. The one directed to the silylmethyl site behaves as a highly reactive and (E)-selective condensation reagent to aldehydes.     

Sugar-water interaction from diffusion measurements

The diffusion coefficients of deoxyribose and ribose in water were measured at 25°C. The Stokes-Einstein relation for mono-, di-, and tri-saccharides are discussed. The diffusion coefficient at infinite dilution D_o for deoxyribose was the largest among these sugars. It appears that the deoxyribose breaks local water structure but the ribose hardly affects the structure. D_o correlates well with the mean number of e-OH groups in the sugar molecule. It is suggested that the mean number of e-OH groups is a good parameter to describe the properties of sugar hydration.