Simultaneous Observation of NO2 Column Density and Aerosol Optical Thickness in Urban Atmosphere

Ground-based, optical monitoring of the NO₂ column density and aerosol optical thickness is described. The instrument consists of a solar radiation spectrometer and a conventional sunphotometer, both mounted on a sun-tracker and operated automatically. From daytime measurements in Chiba during the winter of 1998, variations of NO₂ and aerosol are analyzed. Because of the capability of simultaneous, real time measurement, this method is particularly suitable for air pollution studies in city areas.     

Large-scale first-principles molecular dynamics for electrochemical systems with O(N) methods

A method for large-scale first-principles molecular dynamics (MD) simulations on electrochemical systems has been developed by combining the effective screening medium (ESM) method with O(N) density functional theory (DFT). This implementation has been significantly simplified by the introduction of neutral atom potentials, which minimizes the modifications to existing DFT code. In order to demonstrate ability of this implementation, it has been applied to an electrochemical system consisting of a H-Si(111) electrode, which is a candidate anode for high-capacity Li-ion secondary batteries, and a propylene carbonate (PC) solvent to simulate how PC molecules in the vicinity of the electrode surface respond to an imposed electric field. The large-scale MD simulation clearly demonstrates that the combination of the ESM and O(N) DFT methods provides a useful tool for first-principles investigation of complicated electrochemical systems such as high-capacity batteries.     

Effect of chiral diene ligands in rhodium-catalyzed asymmetric addition of arylboronic acids to α,β-unsaturated sulfonyl compounds

Asymmetric addition of arylboronic acids to α,β-unsaturated sulfonyl compounds proceeded in the presence of a rhodium catalyst coordinated with a chiral diene ligand to give high yields of the addition products with high enantioselectivity (96->99.5% ee). The diene ligand was proved to be essential for the formation of the addition products, while the use of a bisphosphine ligand mainly gave the cine-substitution product.     

Rhodium-catalyzed asymmetric addition of arylboroxines to β-alkoxyacrylate esters

Asymmetric addition of arylboroxines to β-alkoxyacrylate esters proceeded in the presence of a rhodium complex coordinated with a chiral diene ligand to give high yields of β-alkoxy-β-arylcarboxylic acid esters with very high enantioselectivity.