Study of optical response of spinel oxide by utilizing IR-THz spectromicroscopy

We performed a spectromicroscopic measurement on LiV₂O₄ in IR-THz (25 meV–1.5 eV) from 6–300 K under high pressures up to 20 GPa by using a DAC at the spectromicroscopy station (BL43IR) at SPring-8. At 40 K, a clear metal–insulator change was observed above 6 GPa in the optical conductivity spectra. The newly developed peak structure around 1 eV reflects the pseudo-gap forming under pressure at 40 K.     

Molecular dynamics simulations of structural disordering and forming defects in a milling process for selenium

In our previous paper, structural changes of selenium powders ground by a planetary ball mill at various rotational speeds were investigated for the nanostructural modification of particles using mechanical grinding process. The experimental results indicated that the amorphisation of Se by grinding accompanies lattice strain, and the lattice strain arises from impact energy which is more than an energy related to intermolecular interaction. In this paper, molecular dynamics simulations of selenium have been carried out under compressing conditions of various pressure strengths for obtaining information of the lattice strain at atomic level. Then, dynamical behaviour of atomic configuration has been discussed in this process. The structural disordering and formation of the structural defects were estimated by deviations of bond length and angle and the number of created defects before and after compressing from simulated results. The disordering took place during compressing at various pressure strengths, and the disordered atoms return to their initial positions at lower pressure. Stable disordered state and defects after the compression can however remain by compression at more than a certain pressure strength mainly associated with binding energy of selenium.     

A versatile route to silylsubstituted ketones by rhodium catalyzed isomerization of silylated allyl alcohols

The rhodium catalyzed isomerization of α-, β-, and γ-silylated allyl alcohols has been successfully applied to the selective synthesis of acylsilane, α-silyl ketones, and β-silyl ketones, respectively.     

Preparation of Na+-selective electrodes by ion-implantation of lithium and silicon into single-crystal alumina wafer and its application to the production of ISFET

Summary Sodium ion-selective electrodes (Na⁺-ISE) were prepared by implanting Si⁺ and Li⁺ into alumina wafers and their characteristics were investigated. The alumina wafer had a thickness of 100 m and a diameter of 1.40 cm. The ionselective membrane was produced by ion-implanting of Li⁺ and Si⁺ on both sides of a single-crystal alumina wafer. The total doses of Li⁺ and Si⁺ were controlled to be the same, viz. 10¹³–10¹⁵ ions/cm². The ion-implanted alumina wafer with 10¹⁴ or 4×10¹⁴ ions/cm² of Li⁺ and Si⁺ showed better characteristics than the others.The response curves of the 10¹⁴ ions/cm² implanted alumina wafer had a slope of 42 mV/pNa in a concentration range from 1–10^–4mol/l. The full response achieved after about 1 min was reproducible. The proposed idea of producing Na⁺-ISE by ion-implantation technique was applied to functuate the gate surface of the field effect transitor to sodium ion. The sodium ion-sensitive FET (Na⁺-ISFET) prepared by implanting Li⁺ and Al⁺ at a dose of 5×10¹⁴ ions/cm² showed a slope of 30 mV/pNa in a concentration range from 1–10^–4mol/l.

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Herstellung Na⁺-ionenselektiver Elektroden durch Einbau von Lithium und Silicium in Einkristall-Alumniumoxidblättchen und Anwendung zur Erzeugung von ISFET

Zusammenfassung Na⁺-selektive Elektroden wurden durch Einbau von Si⁺ und Li⁺ in Aluminiumoxidblättchen hergestellt und ihre Charakteristiken untersucht. Die Blättchen hatten eine Dicke von 100 m und einen Durchmesser von 1,40 cm. Ebenso wurde die Membran für einen ISFET hergestellt. Die Gesamtmenge von Li⁺ und Si⁺ wurde auf 10¹³–10¹⁵ Ionen/cm² eingestellt, wobei sich bei 10¹⁴ oder 4×10¹⁴ Ionen/cm² die beste Charakteristik ergab.Die Responsekurven der mit 10¹⁴ Ionen/cm² versehenen Aluminiumoxidplättchen hatten eine Neigung von 42 mV/pNa in einem Konzentrationsbereich von 1–10^–4mol/l. Der nach 1 min erhaltene volle Response war reproduzierbar. Die vorgeschlagene Technik wurde zur Einstellung der Gate-Oberfläche des Feldeffekt-Transistors auf Natriumion benutzt. Der Na⁺-sensitive FET (Na⁺-ISFET), der durch Einbau von Li⁺ und Al⁺ mit 5×10¹⁴ Ionen/cm² hergestellt wurde, zeigte eine Neigung der Signalkurve von 30 mV/pNa in einem Bereich von 1–10^–4mol/l.

     

Stereocontrolled synthesis of α,β-unsaturated carboxylic esters from O-methyl-C,O-bis(trimethylsilyl)ketene acetal and aliphatic aldehydes

(R*,S*) Selective aldol type reaction of O-methyl-C,O-bis(trimethylsilyl)ketene acetal ($\text{1}$) with aldehydes and stereoselective formation of α,β-unsaturated carboxylic esters are attained by the combination of Z-$\text{1}$ and Lewis acids.     

Effect of temporal resolution on the estimation of left ventricular function by cardiac MR imaging

The aim of this study was to investigate the effect of temporal resolution on the estimation of left ventricular (LV) function by cardiac magnetic resonance (MR) imaging using a steady-state free precession (SSFP) sequence. Left ventricular function was assessed by cine MR imaging using a segmented SSFP sequence in 10 healthy volunteers. Views per segment (VPS) were set at 8 and 20, resulting in high and low true temporal resolution, respectively. Irrespective of VPS, images were reconstructed at 40 cardiac phases, providing high apparent temporal resolution. Data were analyzed using 40, 20 and 10 phases to simulate different apparent temporal resolutions. Increasing the cardiac phases used for analysis slightly decreased mean end-systolic volume (ESV) and slightly increased mean ejection fraction (EF). No substantial difference in estimates of end-diastolic volume (EDV) was found between VPSs of 8 and 20. Imaging with a VPS of 20 yielded a larger ESV and smaller EF than imaging with a VPS of 8 when 40 phases were used. In conclusion, low true temporal resolution causes overestimation of ESV and underestimation of EF. Improvement of apparent temporal resolution mildly reduces but does not eliminate the errors caused by low true temporal resolution.