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A series of anatase phase Fe-doped TiO2 nanoparticles are prepared by a modified sol-gel method. Spontaneous Raman spectroscopy is utilized to characterize the crystal structures of these nanoparticles and investigate their structural transformation under the exposure of a 532 nm green laser. The anatase phase of TiO2 can be effectively converted into the rutile phase with the assistance of Fe doping. It is found that the critical laser intensity for phase transformation decreases with increasing the Fe content. We ascribe this tendency to the enhanced optical absorption and the photo-induced thermal heating effect, which can be associated with the defect structure within the bandgap of Fe- TiO2 nanoparticles. Our study demonstrates an all-optical approach to pump and probe the phase transformation of metal-doped TiO2 nanoparticles.

The electrical and magnetic properties of slightly Cu-deficient BiOCu(0.94)S are investigated using neutron diffraction, ac magnetic susceptibility, magnetization and electrical resistivity measurements. The Cu spins order in a ferromagnetic arrangement below T(C) = 250 K. An antiferromagnetic component develops below 180 K when the crystalline unit cell experiences a sharp thermal contraction upon cooling, resulting in a canted ferromagnetic spin arrangement at low temperatures. In the magnetically ordered state the electrical transport can be described using three-dimensional variable range hopping conduction. An applied magnetic field can effectively reduce the hopping barrier. Spin-charge couplings are clearly revealed when the resistivity departs from the hopping conduction and begins to increase with increasing temperatures above 250 K where the Cu spins become disordered.

Abstract-XPose is a new touch-based interactive system for photo taking, designed to take advantage of the autonomous flying capability of a drone-mounted camera. It enables the user to interact with photos directly and focus on taking photos instead of piloting the drone. XPose introduces a two-stage eXplore-and-comPose approach to photo taking in static scenes. In the first stage, the user explores the "photo space" through predefined interaction modes: Orbit, Pano, and Zigzag. Under each mode, the camera visits many points of view (POVs) and takes exploratory photos through autonomous drone flying. In the second stage, the user restores a selected POV with the help of a gallery preview and uses direct manipulation gestures to refine the POV and compose a final photo. Our prototype implementation, based on a Parrot Bebop quadcopter, relies mainly on a single monocular camera and works reliably in a GPS-denied environment. A systematic user study indicates that XPose results in more successful user performances in phototaking tasks than the touchscreen joystick interface widely used in commercial drones today.

Neutron diffraction, magnetic susceptibility, specific heat, and dielectric constant measurements of single crystal Co 3 TeO 6 have been measured to study the interplay between the ferroelectricity and magnetic order. Long range incommensurate magnetic order develops below T M1 =26 K, which is followed by three additional zero-field phase transitions at T M2 =19.5 K, T M3 =18 K, and T M4 =16 K where the incommensurate order changes and commensurate order develops. In magnetic fields up to 14 T we find that the magnetic intensities and incommensurate wave vector are dramatically altered as ferroelectricity develops, with a fifth abrupt transition around 10 T. The overall behavior characterizes Co 3 TeO 6 as a type-II multiferroic.Ferroelectricity is a physical phenomenon where spontaneous electrical polarization P appears below a certain temperature T C . Ferroelectric order can arise in a number of ways, such as from a structural change, a spin-exchange interaction, or spin-orbit interaction that triggers relative displacements of the positive and negative ions. 1-6 Multiferroics, where both ferroelectric and magnetic order coexist, are quite uncommon, but are of particular interest both to understand the fundamental interactions between the two types of order as well as for the potential for practical applications. 7-9 For conventional (type-I, or proper) ferroelectrics the two types of order must be associated with different atoms, with generally a weak interaction between the two order parameters. For type-II (improper) ferroelectrics, on the other hand, the ferroelectric displacements