Non-equilibrium Green's function (NEGF) and quantum master equation (QME) are two main classes of approaches for electronic transport. We discuss various Floquet variances of these formalisms for transport properties of a quantum dot driven via interaction with an external periodic field. We first derived two versions of the Floquet NEGF. We also explore an ansatz of the Floquet NEGF formalism for the interacting systems. In addition, we derived two versions of Floquet QME in the weak interaction regime. With each method, we elaborate on the evaluation of the expectation values of the number and current operators. We examined these methods for transport through a two-level system that is subject to periodic driving. The numerical results of all four methods show good agreement for non-interacting systems in the weak regime. Furthermore, we have observed that circular light can introduce spin current. We expect these Floquet quantum transport methods to be useful in studying molecular junctions exposed to light.
Relationships of toxicities from intravenous (i.v.), intraperitoneal (i.p.), subcutaneous (s.c.) and intragastric (i.g.) exposure routes to mice were investigated. Regression analysis showed that the toxicities from i.v. route is strongly correlated with i.p. and s.c. routes, but poorly with i.g. route. Close toxicities from different routes for some compounds indicate that distribution rate is the determining step and dictates chemical concentration at the target site(s). On the other hand, the absorption rate is the determining step for many compounds, which lead to different toxicities between exposure routes. The classified compounds characterized as having either absorption or distribution rate determining step were based upon the comparison of toxicities from the different routes. We found that some aliphatic acids and benzoic acids have lower toxicity values from i.g. route compared to an i.v. route because of poor absorption. Many compounds show low toxic effects from i.g. route than those from other routes because of the first-pass metabolism in the gastrointestinal tract, resulting in the poor relationship for toxicities between i.g. and i.v. or other routes. Stepwise regression analysis showed that physicochemical properties of a compound, such as molecular volume, polarizability and hydrophobicity, significantly affect adsorption rate, which leads to different toxicities based upon exposure routes. Comparison of the toxicities between mice and rats indicate that toxic effect and the toxicokinetic processes in mice are very similar to that in rats. A universal correlation equation has been developed for the toxicities between rats and mice from different exposure routes, which can be applied to predict toxicities across species.
This paper describes the challenges faced by the microelectronics community in growing ultra-thin films using Atomic Layer Deposition and summarizes how mechanistic information derived from in situ infrared absorption spectroscopy studies can guide the growth of sub-nanometer films. Examples are drawn from the growth of high-k dielectrics (e.g. HfO2 ) on oxide-free silicon surfaces to achieve the lowest effective oxide thickness.
This review introduce the basic principle of ion mobility spectrometry and recent progress on the instrument.We put emphasis on the application of ion mobility spectrometry in pharmaceutical analysis and medicine,and include outlooks on its future development.
A two-step deposition process was developed to deposit highly c-axis oriented AlN thin films on titanium alloy substrates by middle-frequency magnetron sputtering. Smooth AlN seed layer was first prepared on rough titanium alloy substrate at the first step. Then, c-axis oriented AlN films with small grain size were deposited at the second step. The effects of the growth time at the first and second step on the microstructure and the c-axis orientation of the AlN films were studied. It was found that the c-axis orientation of the AlN films is strongly dependent on the film thickness at the first step and the substrate temperature at the second step. With optimal process conditions, the full-width at half-maximum of the AlN (0002) peak rocking curve decreased to a minimum of 4.1° and the root-mean-square surface roughness of the prepared AlN films was 4.3 nm. The prepared AlN films have potential applications in piezoelectric microelectromechanical-systems and surface acoustic wave devices.
A novel organic phosphorescent white-light-emitting device (WOLED) with configuration of ITO/NPB/NPB:Ir(piq)2(acac)/CBP:TBPe /BAlq:rubrene/BAlq/Alq3/Mg:Ag is fabricated successfully, in which the phosphorescent dye (Ir(piq)2(acac)) doped into NPB (hole transport material), fluorescent dye (TBPe) doped into CBP (ambipolar conductivity material) and another fluorescent dye (rubrene) doped into BALq (electron transport material) work as the red, blue and green emitting layer, respectively. The emitting layers are sandwiched between the undoped NPB and BALq layers. The charge distribution has been balanced for the introduction of heterojunctions between the different emitting layers, which results in a high fabrication reproducibility of the device. White emission is obtained by tuning the thickness and doping proportions of each layer. The device turns on at the driving voltage of 4.5 V. It shows a maximum external quantum efficiency and brightness of 1.5 % and 16260 cd/m2, respectively. The Commission Internationale de l'Eclairage (CIE) coordinates varies from (0.396, 0.432) at 5 V to (0.411, 0.414) at 20 V. The emission spectra of the device mainly consist of blue (464 nm), green (552 nm) and red (620 nm) emissions peaks, which are particular suitable to be combined with color filters to obtain the three primary colors and further achieve full color displays.
All the source data, codes and raw images used in main text and supplementary information of "An atomic-scale multi-qubit platform" are supplied in the file.
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