High pressure studies of viscosity effects on isomerization

Abstract

The viscosity dependence of the isomerization process with comparatively low potential barrier was studied as a model of one-dimensional barrier crossing.

We found that the ground-state isomerization of DODCI fails to fit the Kramers equation. We analyzed this non-Kramers behavior by means of an approach of frequency dependent friction.     

Syntheses and characterization of a new class of mono‐ and heterodinuclear derivatives of boron derived from Schiff bases

Reactions of 2‐isopropoxy‐1, 3, 2‐ benzodioxaborole with equivalent amounts of Schiff base ligands having two hydroxyl groups ( 1a–3a ) yield mononuclear derivatives with one residual hydroxy group. The reactions of these mononuclear derivatives with hexamethyldisilazane in a 2:1 ratio yield heterodinuclear derivatives. All these newly synthesized derivatives have been characterized by elemental analyses and molecular weight measurements. Tentative structures have been proposed on the basis of IR and NMR (¹H, ¹³C, ¹¹B,²⁹Si)spectral data and Fab‐mass studies. Schiff bases and their corresponding mono‐ and heterodinuclear derivatives of boron have also been screened for antifungal activities. Copyright © 2010 John Wiley & Sons, Ltd.     

Monte Carlo simulation of GM probe and NaI detector efficiency for surface activity measurements

This paper deals with the direct measurement of total (fixed plus removable) surface activity in the presence of interfering radiation fields. Two methods based on Monte Carlo simulations are used: one for a Geiger–Muller (GM) ionisation probe and the other for sodium iodide (NaI) detector with lead collimators; equations for the most general case and the geometry models for Monte Carlo simulation of both (GM and NaI) detectors are employed. Finally, an example of application is discussed.     

Electric Field Gradients of B in TiO2

We observed the electric quadrupole interaction of ¹²B implanted in the interstitial site of TiO₂ using β-NMR method. The electric field gradients including the direction of the principal axes were determined. The direction agreed well with the theoretical calculation.     

一种间接测量圆柱形管内样品冲击波压力的方法

 描述了一种联合使用锰铜计和康铜计间接测量柱对称滑移爆轰条件下，金属管内样品中冲击波压力的方法。给出了冲击压缩方法合成纤锌矿型氮化硼（wBN）时的测量结果。结果表明：管内样品中压力范围大致在11.5~22 GPa范围内，满足冲击波合成wBN所需的压力条件；管内样品压力的发展变化具有不连续性。证明了这种间接测量管内压力的方法是可行的。     

Quantum chemical investigation on one- and two-photon absorption properties for a series of donor-π-acceptor-type compounds with trivalent boron as an acceptor

In this paper, one- and two-photon absorption properties as well as the transition nature of a series of donor-π-acceptor-type compounds with trivalent boron as an acceptor have been theoretically studied by using INDO/SDCI method. Our calculations indicate that the four o-methyl moieties on the two mesityl groups play an important part in protecting the trivalent boron from being attacked by oxygen in the air. The trivalent boron containing group can be an all-right electron-acceptor with some bulky groups attached to it. On the basis of geometry optimization and UV–vis spectra, the positions and strengths of two-photon absorption for these molecules were reported.