Permanent data recording in transparent materials by using a nanojoule-class pulse laser

We investigated data recording for permanent data storage using an ultrafast pulse laser with nanojoule-class pulse energy and megahertz-class repetition rate in transparent materials, and driveless reading based on a simple imaging system. A transparent ceramics called Lumicera®, manufactured by Murata Mfg. Co., Ltd., was used as the recording medium. Lumicera® has a lower modification threshold and a higher recording sensitivity than those of silica glass, namely, the medium previously studied. Structural modification in Lumicera® occurs by light exposure for 10 μs, suggesting that Lumicera® has potential for a recording speed of over 100 kbps. Data recorded in Lumicera® resists heating for 2 h at 1000 °C and is expected to have a lifetime of over 300 million years. Moreover, the data recorded in Lumicera® was successfully read with a reading system based on a smart phone.     

Mössbauer study of gamma‴-iron nitride film

A single-phase γ?-FeN film with the rock-salt structure was produced by pulsed laser deposition of Fe onto an Al substrate in a N₂ atmosphere. Its Mössbauer spectra and powder X-ray diffraction patterns were measured. γ?-FeN was found to be antiferromagnetic exhibiting a hyperfine magnetic field of 30 T at a temperature of 5 K. It was found to have a Néel temperature of 220 K. A minor component with a higher hyperfine magnetic field of 49 T at 5 K was also observed. It is thought to originate from defects in γ?-FeN.     

Sulfation of Polysaccharides using Monomethyl Sulfate

ABSTRACT

The polysaccharides, curdlan, starch and dextran were sulfated when heated in DMSO with sodium methyl sulfate and a catalytic amount of H₂SO₄ or with pyridinium methyl sulfate. Use of diminished pressure and anhydrous CaSO₄ as a desiccant improved the degree of sulfation and recovery. Under conditions using sodium methyl sulfate, H₂SO₄ and CaSO₄ in vacuo, sulfation at O-6 was predominant in the cases of curdlan and starch, while sulfation at O-2 and O-3 was preferential in the case of dextran.     

Asymmetric hydrosilylation of cyclohexa-1,3-diene with trichlorosilane by palladium catalysts coordinated with chiral phosphoramidite ligands

Chiral phosphoramidite ligands prepared from (S)-binaphthol and various secondary amines were examined for the palladium-catalyzed asymmetric hydrosilylation of cyclohexa-1,3-diene with trichlorosilane. With a sterically demanding phosphoramidite bearing bis(diphenylmethyl)amine, the high enantiomeric excess of 87% was achieved, which is the highest enantioselectivity in the hydrosilylation of cyclohexadiene reported to date. The catalytic activity in the present hydrosilylation was high with all of the ligands employed, while the enantioselectivities varied dramatically depending on the dialkylamine moiety of the phosphoramidite ligand.     

Practical preparation of chiral keto-imine type ONO Schiff base ligands

A practical preparation of chiral keto-imine type ONO Schiff base ligands has been reported. Metal complexes of these Schiff bases work as efficient chiral catalysts in a variety of asymmetric reactions.