Photoemission study of TiO2/VO2 interfaces

We have measured photoemission spectra of two kinds of TiO$_2$-capped VO$_2$ thin films, namely, that with rutile-type TiO$_2$ (r-TiO$_2$/VO$_2$) and that with amorphous TiO$_2$ (a-TiO$_2$/VO$_2$) capping layers. Below the Metal-insulator transition temperature of the VO$_2$ thin films, $\sim 300$ K, metallic states were not observed for the interfaces with TiO$_2$, in contrast with the interfaces between the band insulator SrTiO$_3$ and the Mott insulator LaTiO$_3$ in spite of the fact that both TiO$_2$ and SrTiO$_3$ are band insulators with $d^0$ electronic configurations and both VO$_2$ and LaTiO$_3$ are Mott insulators with $d^1$ electronic configurations. We discuss possible origins of this difference and suggest the importance of the polarity discontinuity of the interfaces. Stronger incoherent part was observed in r-TiO$_2$/VO$_2$ than in a-TiO$_2$/VO$_2$, suggesting Ti-V atomic diffusion due to the higher deposition temperature for r-TiO$_2$/VO$_2$.Comment: 5 pages, 6 figure

ANALYSIS OF MORAL VALUE IN THE MOVIE ZOOTOPIA BY RICH MOORE AND BYRON HOWARD

A movie is a form of literary work which has the main function as a means of entertainment. Apart from just being entertaining, films also have the potential as a learning tool because they provide audio and visual stimuli that can attract the attention of the audience and convey various moral values that describe the principles underlying good and bad actions. It is important for students to be introduced to and taught about these moral values so that they can understand and learn them well. This study of the moral The theme in the film Zootopia aims to explore educational possibilities that can be obtained from watching films, by utilizing visual storytelling techniques. The film acts as a medium that influences conveying information and messages to the audience so that the moral values contained in it can be understood and studied by the audience. This research aims to identify the various moral values presented in the film Zootopia and reveal the moral values implied in the narrative. This research uses library research with a qualitative descriptive method approach. The data for this research are the moral values contained in the dialogue scripts spoken by the characters when shown in the film. The data source for this research comes from the film entitled "Zootopia". Writing uses documentation techniques to collect data. Apart from that, researchers used data analysis. The findings should that the values contained in the moral values in Zootopia. By applying qualitative methodology, The main data source is the Zootopia film itself which is equipped with subtitle files. The research results show that several moral values contained in the film "Zootopia" are stories that raise several important moral values in life, including respect, justice, self�confidence, tolerance, helping each other, and altruism

Sensing behavior of acetone vapors on TiO2_2 nanostructures --- application of density functional theory

The electronic properties of TiO$_2$ nanostructure are explored using density functional theory. The adsorption properties of acetone on TiO$_2$ nanostructure are studied in terms of adsorption energy, average energy gap variation and Mulliken charge transfer. The density of states spectrum and the band structure clearly reveals the adsorption of acetone on TiO$_2$ nanostructures. The variation in the energy gap and changes in the density of charge are observed upon adsorption of acetone on n-type TiO$_2$ base material. The results of DOS spectrum reveal that the transfer of electrons takes place between acetone vapor and TiO$_2$ base material. The findings show that the adsorption property of acetone is more favorable on TiO$_2$ nanostructure. Suitable adsorption sites of acetone on TiO$_2$ nanostructure are identified at atomistic level. From the results, it is confirmed that TiO$_2$ nanostructure can be efficiently utilized as a sensing element for the detection of acetone vapor in a mixed environment.Comment: 13 pages, 14 figures, 3 table

Nanotoxicity of polyelectrolyte-functionalized titania nanoparticles towards microalgae and yeast: Role of the particle concentration, size and surface charge

We studied the nanotoxicity of titania nanoparticles (TiO₂NPs) of various hydrodynamic diameters and crystallite sizes towards C. reinhardtii microalgae and S. cerevisiae (yeast) upon illumination with UV and visible light. The cell viability was assessed for a range of nanoparticle concentrations and incubation times. We found that bare TiO₂NPs affect the C. reinhardtii cell viability at much lower particle concentrations than for yeast. We observed an increase of the TiO₂NPs toxicity upon illumination with UV light compared with that in dark conditions due to the oxidative stress of the produced reactive oxygen species. We also found an increased TiO₂NPs nanotoxicity upon illumination with visible light which indicates that they may also interfere with the microalgae's photosynthetic system leading to decreased chlorophyll content upon exposure to TiO₂NPs. The results indicate that the larger the hydrodynamic diameter of the TiO₂NPs the lower is their nanotoxicity, with anatase TiO₂NPs generally being more toxic than rutile TiO₂NPs. We also prepared a range of polyelectrolyte-coated TiO₂NPs using a layer by-layer method and studied their nanotoxicity towards yeast and microalgae. We found that the toxicity of the coated TiO₂NPs changes with their surface charge. TiO₂NPs coated with cationic polyelectrolyte as an outer layer exhibit much higher nanotoxicity than the ones with an outer layer of anionic polyelectrolyte. TEM images of sectioned microalgae and yeast cells exposed to different polyelectrolyte-coated TiO₂NPs confirmed the formation of a significant build-up of nanoparticles on the cell surface for bare and cationic polyelectrolyte-coated TiO₂NPs. The effect comes from the increased adhesion of cationic nanoparticles to the cell walls. Significantly, coating the TiO₂NPs with anionic polyelectrolyte as an outer layer led to a reduced adhesion and much lower nanotoxicity due to electrostatic repulsion with the cell walls. This suggest a new way of making cationic TiO₂NPs safer for use in different formulations by pre-coating them with anionic polyelectrolytes. The results of this study give important insights into the various factors controlling the nanotoxicity of TiO₂NPs

Comparing quasiparticle H2_2O level alignment on anatase and rutile TiO2_2

Knowledge of the molecular frontier levels' alignment in the ground state can be used to predict the photocatalytic activity of an interface. The position of the adsorbate's highest occupied molecular orbital (HOMO) levels relative to the substrate's valence band maximum (VBM) in the interface describes the favorability of photogenerated hole transfer from the VBM to the adsorbed molecule. This is a key quantity for assessing and comparing H$_2$O photooxidation activities on two prototypical photocatalytic TiO$_2$ surfaces: anatase (A)-TiO$_2$(101) and rutile (R)-TiO$_2$(110). Using the projected density of states (DOS) from state-of-the-art quasiparticle (QP) $G_0W_0$ calculations, we assess the relative photocatalytic activity of intact and dissociated H$_2$O on coordinately unsaturated (Ti$_{\textit{cus}}$) sites of idealized stoichiometric A-TiO$_2$(101)/R-TiO$_2$(110) and bridging O vacancies (O$_{\textit{br}}^{\textit{vac}}$) of defective A-TiO$_{2-x}$(101)/R-TiO$_{2-x}$(110) surfaces ($x=\frac{1}{4},\frac{1}{8}$) for various coverages. Such a many-body treatment is necessary to correctly describe the anisotropic screening of electron-electron interactions at a photocatalytic interface, and hence obtain accurate interfacial level alignments. The more favorable ground state HOMO level alignment for A-TiO$_2$(101) may explain why the anatase polymorph shows higher photocatalytic activities than the rutile polymorph. Our results indicate that (1) hole trapping is more favored on A-TiO$_2$(101) than R-TiO$_2$(110) and (2) HO@Ti$_{\textit{cus}}$ is more photocatalytically active than intact H$_2$O@Ti$_{\textit{cus}}$

Shear viscosity of alkali and alkaline earth titanium silicate liquids

The shear viscosities of l3 silicate liquids along the NarSiOr-TiO, and CaSiOr-TiO, joins as well as six liquids based on the sphene stoichiometry X#TiSiO. (where X represents Li, Na, K, Rb, Cs, Ca, and Sr) have been measured in equilibrium with air using the concentric cylinder method. The NarSiOr-TiO, join was investigated from l0 to 50 mol0/oT iO, in the temperaturer ange 1000-1150 "C, whereast he CaSiO3-TiO,jo in was investigated from l0 to 80 molo/oT iO, in the temperature range of 1400-1625' C. The shear viscosities of liquids in the CaSiOr-TiO, and NarSiOr-TiO2 systems decrease with the addition of TiO,. The decreaseis linear in the CaSiOr-TiO, system at 1400- I 600 'C but nonlinear in the NarSiO3-TiO, system at 1000-1 150'C. Viscosities of melts of sphene stoichiometry, X1;TiSiO, (where X: Cs, Rb, K, Na, Li, Ba, Sr, and Ca), decrease with increasing field strength. Similar to the behavior of ferro-, alumino-, and galliosilicate melts, this decreaseis strong for the alkalies but very weak for the alkaline earths

Review of the Structural Stability, Electronic and Magnetic Properties of Nonmetal-Doped TiO2_2 from First-Principles Calculations

This paper reviews and summarizes the recent first-principles theoretical studies of the structural stability, electronic structure, optical and magnetic properties of nonmetal-doped TiO$_2$. The first section presents a comparison study of the structural stability for X-anion and X-cation doped TiO$_2$ (X=B, C, Si, Ge, N, P, As, Sb, S, Se, Te, F, Cl, Br, and I), which reveals that the sites of nonmetal dopants (i.e., at O sites or at Ti sites) in TiO$_2$ are determined by the growth condition of doped TiO$_2$ and the dopants' electronegativities. The next section reviews the electronic structure, optical absorption and mechanism of the visible-light photocatalytic activity for nonmetal-doped TiO$_2$. The third section summarizes the origin of the spin-polarization and the magnetic coupling character in C- (N- and B-) doped TiO$_2$.Comment: 21 pages, 24 figures, 3 table

The once-daily fixed-dose combination of olodaterol and tiotropium in the management of COPD : current evidence and future prospects

Long-acting bronchodilators are the cornerstone of pharmacologic treatment of chronic obstructive pulmonary disease (COPD). Spiolto (R) or Stiolto (R) is a fixed-dose combination (FDC) containing two long-acting bronchodilators, the long-acting muscarinic receptor antagonist tiotropium (TIO) and the long-acting beta 2-adrenoceptor agonist olodaterol (OLO), formulated in the Respimat (R) Soft Mist (TM) inhaler. A total of 13 large, multicentre studies of up to 52 weeks' duration have documented its efficacy in more than 15,000 patients with COPD. TIO/OLO 5/5 mu g FDC significantly increases pulmonary function compared with placebo and its respective constituent mono-components TIO 5 mu g and OLO 5 mu g. TIO/OLO 5/5 mu g also results in statistically and clinically significant improvements in patient-reported outcomes, such as dyspnoea, use of rescue medication, and health status. Addition of OLO 5 mu g to TIO 5 mu g reduces the rate of moderate-to-severe exacerbations by approximately 10%. Compared with placebo and TIO 5 mu g, TIO/OLO 5/5 mu g significantly improves exercise capacity (e.g. endurance time) and physical activity, the latter increase being reached by a unique combination behavioural modification intervention, dual bronchodilatation and exercise training. Overall, the likelihood for patients to experience a clinically significant benefit is higher with TIO/OLO 5/5 mu g than with its constituent mono-components, which usually yield smaller improvements which do not always reach statistical significance, compared with baseline or placebo. This supports the early introduction of TIO/OLO 5/5 mu g in the management of patients with symptomatic COPD

Effect of non-magnetic impurities on the magnetic states of anatase TiO2_2

The electronic and magnetic properties of TiO$_2$, TiO$_{1.75}$, TiO$_{1.75}$N$_{0.25}$, and TiO$_{1.75}$F$_{0.25}$ compounds have been studied by using \emph{ab initio} electronic structure calculations. TiO$_2$ is found to evolve from a wide-band-gap semiconductor to a narrow-band-gap semiconductor to a half-metallic state and finally to a metallic state with oxygen vacancy, N-doping and F-doping, respectively. Present work clearly shows the robust magnetic ground state for N- and F-doped TiO$_2$. The N-doping gives rise to magnetic moment of $\sim$0.4 $\mu_B$ at N-site and $\sim$0.1 $\mu_B$ each at two neighboring O-sites, whereas F-doping creates a magnetic moment of $\sim$0.3 $\mu_B$ at the nearest Ti atom. Here we also discuss the possible cause of the observed magnetic states in terms of the spatial electronic charge distribution of Ti, N and F atoms responsible for bond formation.Comment: 11 pages, 4 figures To appear J. Phys.: Condens. Matte

Origin of the different conductive behavior in pentavalent-ion-doped anatase and rutile TiO2_2

The electronic properties of pentavalent-ion (Nb$^{5+}$, Ta$^{5+}$, and I$^{5+}$) doped anatase and rutile TiO$_2$ are studied using spin-polarized GGA+\emph{U} calculations. Our calculated results indicate that these two phases of TiO$_2$ exhibit different conductive behavior upon doping. For doped anatase TiO$_2$, some up-spin-polarized Ti 3\emph{d} states lie near the conduction band bottom and cross the Fermi level, showing an \emph{n}-type half-metallic character. For doped rutile TiO$_2$, the Fermi level is pinned between two up-spin-polarized Ti 3\emph{d} gap states, showing an insulating character. These results can account well for the experimental different electronic transport properties in Nb (Ta)-doped anatase and rutile TiO$_2$.Comment: 4 pages, 5 figure