A wide range of interferometric techniques recover phase information that is mathematically wrapped on the interval (-pi, pi). Obtaining the true unwrapped phase is a longstanding problem. We present an algorithm that solves the phase unwrapping problem, using a combination of Fourier techniques. The execution time for our algorithm is equivalent to the computation time required for performing eight fast Fourier transforms and is stable against noise and residues present in the wrapped phase. We have extended the algorithm to handle data of arbitrary size. We expect the state of the art of existing interferometric applications, including the possibility for real-time phase recovery, to benefit from our algorithm.

As silicon-based electronics are reaching the nanosize limits of the semiconductor roadmap, carbon-based nanoelectronics has become a rapidly growing field, with great interest in tuning the properties of carbon-based materials. Chemical functionalization is a proposed route, but syntheses of graphene oxide (G-O) produce disordered, nonstoichiometric materials with poor electronic properties. We report synthesis of an ordered, stoichiometric, solid-state carbon oxide that has never been observed in nature and coexists with graphene. Formation of this material, graphene monoxide (GMO), is achieved by annealing multilayered G-O. Our results indicate that the resulting thermally reduced G-O (TRG-O) consists of a two-dimensional nanocrystalline phase segregation: unoxidized graphitic regions are separated from highly oxidized regions of GMO. GMO has a quasi-hexagonal unit cell, an unusually high 1:1 O:C ratio, and a calculated direct band gap of ∼0.9 eV.

A nanoscale phase is known to coincide with colossal magnetoresistance (CMR) in manganites, but its volume fraction is believed to be too small to affect CMR. Here we provide scanning-electron-nanodiffraction images of nanoclusters as they form and evolve with temperature in La(1-x)Ca(x)MnO(3), x = 0.45. They are not doping inhomogeneities, and their structure is that of the bulk compound at x = 0.60, which at low temperatures is insulating. Their volume fraction peaks at the CMR critical temperature and is estimated to be 22% at finite magnetic fields. In view of the known dependence of the nanoscale phase on magnetic fields, such a volume fraction can make a significant contribution to the CMR peak.

Temporomandibular joint pain dysfunction syndrome (TMJPDS) comprises of a constellation of signs and symptoms including joint tenderness and pain on function, restricted jaw movement, clicking, jaw locking and tenderness in the muscles of mastication. Headache may also be a feature. Physiotherapy is commonly employed in the treatment of this condition but there is little published material reporting the relative efficacy of the different types of treatment currently available. Further, no attempt seems to have been made to compare the costs of physiotherapy with other forms of treatment of this disorder such as occlusal splint therapy. This paper reports a comparative evaluation of four different physiotherapy treatments and placebo in the management of TMJPDS and comments on their cost benefit aspects compared with that of splint therapy. The four methods of physiotherapy tested were short-wave diathermy, megapulse, ultrasound and soft laser. There was no statistically significant difference in success rate between any of the four tested (range 70.4-77.7%) although each individually was significantly better than placebo treatment. The time of improvement appeared to vary between the four methods.

Polarons, the combined motion of electrons in a cloth of their lattice distortions, are a key transport feature in doped manganites. To develop a profound understanding of the colossal resistance effects induced by external fields, the study of polaron correlations and the resulting collective polaron behavior, i.e., polaron ordering and transition from polaronic transport to metallic transport is essential. We show that static long-range ordering of Jahn-Teller polarons forms a polaron solid which represents a new type of charge and orbital ordered state. The related noncentrosymmetric lattice distortions establish a connection between colossal resistance effects and multiferroic properties, i.e., the coexistence of ferroelectric and antiferromagnetic ordering. Colossal resistance effects due to an electrically induced polaron solid-liquid transition are directly observed in a transmission electron microscope with local electric stimulus applied in situ using a piezo-controlled tip. Our results shed light onto the colossal resistance effects in magnetic field and have a strong impact on the development of correlated electron-device applications such as resistive random access memory (RRAM).correlated electrons ͉ magnetism ͉ oxide M aterials with a coexistence of a variety of electronic and lattice interactions of similar strength are able to create fundamentally differing electronic ground states (1). In doped manganites (Re 1Ϫx A x MnO 3 ; Re and A are rare-and alkaline-earth cations), this includes ferromagnetic metallic, paramagnetic insulating and antiferromagnetic charge and orbital ordered states, representing different collective behavior of the microscopic lattice, charge, orbital, and spin degrees of freedom (2). External fields influence the subtle balance of the interactions and the induced phase transitions between different ground states are related to colossal resistance effects in magnetic (3, 4), electric (5), photon (6), and strain fields (7). They offer great opportunities for new correlated electron devices (8), e.g., in magnetoelectronics and nonvolatile electronic data storage.Among various interactions, two different basic types of electron-lattice coupling (9) play a distinct role in manganites: One is the effect of the static crystal structure on electron transport and bonding. Different ion radii of the involved Re and A cations generate different internal stress on the MnOOOMn bonds. The different resulting types of lattice distortions involve transitions from the ideal cubic to hexagonal, rhombohedral, and orthorhombic structures (10, 11), which may induce polar distortions or even multiferroic ordering, i.e., the presence of electric and magnetic order of electrons in a single phase (12). In doped systems, the decrease of the MnOOOMn bonding angle below 180°due to rigid rotations of the MnO 6 octahedra (for example, see Fig. 2a) results in a strong reduction of the bandwidth of the e g conduction electrons, the conductivity, and the related ferromagnetic double exchange (13).In addit...

Engineering domains in ferroelectric thin films is crucial for realizing technological applications including non-volatile data storage and solar energy harvesting. Size and shape of domains strongly depend on the electrical and mechanical boundary conditions. Here we report the origin of nonswitchable polarization under external bias that leads to energetically unfavourable head-to-head domain walls in as-grown epitaxial PbZr 0.2 Ti 0.8 O 3 thin films. By mapping electrostatic potentials and electric fields using off-axis electron holography and electron-beam-induced current with in situ electrical biasing in a transmission electron microscope, we show that electronic band bending across film/substrate interfaces locks local polarization direction and further produces unidirectional biasing fields, inducing nonswitchable domains near the interface. Presence of oxygen vacancies near the film surface, as revealed by electron-energy loss spectroscopy, stabilizes the charged domain walls. The formation of charged domain walls and nonswitchable domains reported in this study can be an origin for imprint and retention loss in ferroelectric thin films.

No abstract

No abstract