Carbon-13 NMR spectra of arylmethyl carbanions

Carbon-13 chemical shifts of three arylmethyl carbanions have been determined by changing solvents and counter ions. The charge distributions in the carbanions are discussed and compared with those obtained from the ¹H chemical shifts.     

Polarization of neutrons from the d-t reaction and in n-p scattering

The polarization of 32 MeV neutrons from the d-t reaction has been measured using n-He scattering at an angle of 130° (lab). A He gas scintillator was used as a scatterer, and the scattered neutrons were measured by counting the He recoils which were coincident with pulses from the side detector and which were synchronized with the deuteron beam bunch. Polarizations in n-p scattering have been measured using the polarized neutrons at angles of 30°, 40° and 50° (lab).     

Porous coordination polymer hybrid device with quartz oscillator: effect of crystal size on sorption kinetics

A new strategy to synthesize monodispersed porous coordination polymer (PCP) nanocrystals at room temperature was developed and utilized for the formation of PCP thin films on gold substrates with fine control over the crystal sizes using the coordination modulation method. Hybridization of these PCP thin films with an environment-controlled quartz crystal microbalance system allowed determining the adsorption properties for organic vapors (methanol and hexane). In the case of high sensitivity (at the low-concentration dosing of analytes), the sensor response depended on the crystal size but not on the type of analyte. In contrast, at the high-concentration dosing, a clear dependence of the sorption kinetics on the analyte was observed due to significant sorbate-sorbate interaction.     

Temporal electric conductivity variations of hydrogenated amorphous silicon due to high energy protons

Electric conductivity variations of undoped, n-type and p-type hydrogenated amorphous silicon (a-Si:H) thin films irradiated with various energy protons are systematically investigated. Dark conductivity (DC) and photoconductivity (PC) of the undoped samples increase at first due to proton irradiation and then decrease dramatically with increasing proton fluence. The increase in DC and PC becomes greater with increased proton energy. However, this increase is metastable and gradually decreases with time at room temperature. Similar results are observed in the n-type a-Si:H, whereas only a monotonic decrease is observed in DC and PC for the p-type samples. The increase of both DC and PC due to proton irradiation is attributed to metastable donor center generation. On further irradiation both the DC and PC decrease by the accumulation of radiation-induced defects, which act as deep traps and compensate carriers. The decrease in DC and PC becomes less pronounced as the proton energy increase and can be fitted along a universal line when the proton fluence is converted into displacement per atom (dpa).     

Lattice deffects in rutile,TiO2

Abstract

Rutile, TiO₂ having relatively high melting point exhibits strong optical absorption after neutron irradiation (8 × 10¹⁶ n_r/cm²) at 15K. The band peak is located near 0. 96 μ having FWHM 0. 87 eV (at LNT). After inverse recovery at 120K, lattice defects due probably to F centers are annealed out at about 220K.