Results 1 - 10 of 212
Results 1 - 10 of 212. Search took: 0.017 seconds
|Sort by: date | relevance|
[en] A significant laser-induced piezooptical response in novel CdCl0.5J 0.5 nanolayers is obtained under the influence of laser illumination. The maximal piezo-optic response is observed for off-diagonal piezooptical tensor components. The layered structure allowed to obtain the thin specimens of thickness up to 1 nm with mirror-like surfaces. The observed studies show huge dependence of the piezooptics on the nanolayer thickness and the photoinduced beam power density. The effect is completely reversible. This fact allows proposing a new type of nanomaterials, which have significant benefits with respect to the other types of piezooptical materials (i.e. a possibility to use them in the laser operated devices). (paper)
[en] Full text: The properties of 2D materials are sensitive to structural defects. Controlling the nature and concentration of defects therefore provides a means of tailoring material properties for specific applications. Ion irradiation is a well-established technique that provides a practical means of defect engineering, so there is particular value in understanding how the structure and concentration of defects depend on ion-irradiation parameters. This study examines the effect of several important aspects of ion-induced radiation damage in graphene, namely: the effect of the ion fluence and nuclear stopping power (Sn) of incident ions on the concentration and structure of defects; the role of the substrate in damage production; and the significance of collective effects associated with molecular ion irradiation. (author)
[en] Objective: To determine the feasibility of unobtrusively monitoring the respiratory rate (RR) in preterm infants by using a film-like pressure sensor placed between the mattress and the bedding. Approach: The RR was simultaneously measured by processing the chest impedance (CI) and the ballistographic (BSG) signal acquired from the pressure sensor in 10 preterm infants of varying body weight. Nearly 27 h of data were analyzed from these infants while in different body positions including both spontaneously breathing infants and those receiving non-invasive respiratory support. Main results: The RR acquired from the BSG signal (RR-BSG) was significantly correlated (r = 0.74) to the RR derived from the CI (RR-CI) with narrow 95% limits of agreement (10 breaths min−1). A subanalysis of epochs most and least affected by infant movement yielded comparable results. Significance: Irrespective of body weight or infant position, unobtrusively monitoring the RR of preterm infants is feasible using film-like pressure sensors. (paper)
[en] We report fabrication of smooth Al-doped ZnO (AZO) films <100 nm by atomic layer deposition (ALD) with epsilon-near-zero (ENZ) frequencies in the near-infrared region controlled by deposition parameters. Excitation of the ENZ plasmon-polariton mode in the AZO films is experimentally demonstrated. The ALD growth of smooth ultra-thin AZO nanolayers with tunable ENZ frequency enables the development of ultra-compact and tunable metamaterial devices and flat nonlinear/quantum zero-index optics. (paper)
[en] Highlights: • Shear horizontal wave dispersion in nanolayers with surface effects is examined. • Wave velocity is dependent on the layer thickness and surface elastic constants. • Surface elastic constants can be analytically derived from the wave velocity. - Abstract: In this work, the shear horizontal (SH) wave dispersion in two dissimilar nanolayers is investigated by using the surface elasticity theory in which the surface effects are featured by surface elastic constants. It is found that the SH wave dispersion shows distinct dependence on the nanolayer thickness as well as the surface elastic constants. The larger the surface elastic modulus and/or the smaller the thickness, the higher the phase velocity. In particular, as the wave frequency approaches zero, the analytical relation between the phase velocity in the first mode dispersion and the surface elastic constants is deduced. Thereby, a facile method is suggested to determine the surface elastic constants from the phase velocity of SH waves scattered in nanolayers.
[en] Highlights: • Design of Chern insulating phases in honeycomb lattices. • We present a description of how our three groups, working on two different honeycomb lattice materials classes, learned and designed two examples of transition metal oxide nanolayers whose ground states are predicted to be Chern insulators (quantum anomalous Hall insulators). The main features or properties that guided our search are compared and contrasted between the two classes of materials. - Abstract: The search for robust examples of the magnetic version of topological insulators, referred to as quantum anomalous Hall insulators or simply Chern insulators, so far lacks success. Our groups have explored two distinct possibilities based on multiorbital 3d oxide honeycomb lattices. Each has a Chern insulating phase near the ground state, but materials parameters were not appropriate to produce a viable Chern insulator. Further exploration of one of these classes, by substituting open shell 3d with 4d and 5d counterparts, has led to realistic prediction of Chern insulating ground states. Here we recount the design process, discussing the many energy scales that are active in participating (or resisting) the desired Chern insulator phase.
[en] Highlights: • Ultrathin emitting nanolayers (• Interlayers play a new role in hybrid WOLEDs, called averting the concentration quenching. • Unipolar interlayers are more beneficial in doping-free hybrid WOLEDs. • A WOLED achieves the cost/simplicity/efficiency/stability/voltage/luminance trade-off. • The doping-free hybrid WOLEDs show a unique emission mechanism. • The first doping-free WOLED showing sun-like emission has been developed. • The first three-color doping-free WOLED with ultrahigh CRI (> 90) has been developed. • The findings demonstrate the possibility, significance, advance and universality of a novel concept. Doping-free organic light-emitting diodes (OLEDs) have aroused research interest due to their simple properties. However, their performances are unsatisfactory, particularly for doping-free white OLEDs (DF-WOLEDs). Herein, by exploiting ultrathin emitting nanolayers (−1), stable color, low voltage and high luminance. Significantly, its phosphorescent layer is 109 times thinner than that of the representative DF-WOLED. Besides, unlike previous hybrid WOLEDs, the DFH-WOLED shows a unique emission mechanism. Moreover, three-color DFH-WOLEDs exhibit i) a wide color correlated temperature span (2325–8011 K), which is the first DF-WOLED showing sun-like emission; or ii) a color rendering index (CRI) of 91.3, which is the first three-color DF-WOLED with ultrahigh CRI (>90). Such surprising findings will unlock a novel concept that ultrathin emitting nanolayers (<1 nm) are promising to develop simplified but high-performance hybrid WOLEDs, which possess a bright prospect for the next-generation lightings and displays.
[en] The functionalization of fine primary particles by atomic layer deposition (particle ALD) provides for nearly perfect nanothick films to be deposited conformally on both external and internal particle surfaces, including nanoparticle surfaces. Film thickness is easily controlled from several angstroms to nanometers by the number of self-limiting surface reactions that are carried out sequentially. Films can be continuous or semi-continuous. This review starts with a short early history of particle ALD. The discussion includes agitated reactor processing, both atomic and molecular layer deposition (MLD), coating of both inorganic and polymer particles, nanoparticles, and nanotubes. A number of applications are presented, and a path forward, including likely near-term commercial products, is given.