Процессы передачи энергии в эвлитите Sr-=SUB=-3-=/SUB=-Y(PO-=SUB=-4-=/SUB=-)-=SUB=-3-=/SUB=-, по отдельности и одновременно легированном ионами Tb-=SUP=-3+-=/SUP=- и Tm-=SUP=-3+-=/SUP=-

In this work the optical spectroscopy and the energy transfer processes involving the Tb3+and Tm3+ ions, have been studied in eulytite double phosphate hosts of the type Sr3Y(PO4)3 doped with various amounts of the two Ln ions. It has been found that several energy transfer and cross-relaxation processes are active in this class of materials, upon excitation in the 5D4 level of Tb, and in the 1G4 one of Tm. In particular, a Tb→Tm transfer of excitation has been found to quench strongly the 5D4 level of Tb. This process occurs with a transfer efficiency increasing from 0.08 to 0.62, for a donor concentration of 2 mol%, and an acceptor concentration increasing from 2 to 15 mol%. The emission spectra are strongly affected by the presence of Tb⟷Tm energy transfer, and Tm→Tm cross relaxation processes.

Novel Negative Capacitance and Conductance in All Temperatures and Voltages of Au/CNTs/n-Si/Al at Low and High Frequencies

The structure of carbon nanotube CNTs functioning as p-type material deposited over n-type silicon to produce heterojunction of Au/CNTs/n-Si/Al is presented in this study.This work explored the capacitance and conductance at various frequencies, temperatures, and voltages, the novelty here is that negative capacitance and conductance were observed at high frequencies in all temperatures and voltages, whereas capacitance appeared at both high and low frequencies, such as (2x107,1x107,1x102,10) Hz. At high-frequency f = 2x107 Hz, the capacitance raises while the conductance decreases; at all temperatures and voltages, the capacitance and conductance exhibit the same behavior at particular frequencies such as 1x106,1x105,1x104,1x103Hz, however their behavior differs at 2x107,1x107, 1x102 and 10Hz. Investigating the reverse square capacitance with voltage yielded the energy fermi (Ef), density surface of states (Nss), depletion width (Wd), barrier height, series resistance, and donor concentration (Nd)

On the permittivity of titanium dioxide

Conductive rutile TiO2 has received considerable attention recently due to multiple applications. However, the permittivity in conductive, reduced or doped TiO2 appears to cause controversy with reported values in the range 100–10,000. In this work, we propose a method for measurements of the permittivity in conductive, n-type TiO2 that involves: (i) hydrogen ion-implantation to form a donor concentration peak at a known depth, and (ii) capacitance–voltage measurements for donor profiling. We cannot confirm the claims stating an extremely high permittivity of single crystalline TiO2. On the contrary, the permittivity of conductive, reduced single crystalline TiO2 is similar to that of insulating TiO2 established previously, with a Curie–Weiss type temperature dependence and the values in the range 160–240 along with the c-axis.

The Evolving Distribution of Giving in the United States

I compute the share of U.S. household giving accounted for by the American tax units donating the largest amounts over the 1960–2012 period from repeated cross-sectional samples of federal income tax returns. The share of donations accounted for by a minority of top donors rose sharply over this period. Donor concentration has risen both because the largest gifts have grown larger and because more households give little or nothing in any given year.

Micro-kinetic model of electrochemical carbon dioxide reduction over platinum in non-aqueous solvents

Theoretical modeling indicates that proton donor concentration and catalyst geometry control the selectivity to multicarbon products in the electrochemical carbon dioxide reduction reaction.