Measuring Power of Earth Disturbances Using Radio Wave Phase Imager.

Numerous studies have investigated ionospheric waves, also known as ionospheric disturbances. These disturbances exhibit complex wave patterns similar to those produced by solar, geomagnetic, and meteorological disturbances and human activities within the Earth's atmosphere. The radio wave phase imager described herein measures the power of the ionospheric waves using their phase shift seen in phase images produced by the Long Wavelength Array (LWA) at the New Mexico Observatory, a high-resolution radio camera. Software-defined radio (SDR) was used for processing the data to produce an amplitude image and phase image. The phase image revealed the ionospheric waves, whereas the amplitude image could not see them. From the phase image produced from the carrier wave received at the LWA, the properties of the ionospheric waves have been previously characterized in terms of their energy and wave vector. In this study, their power was measured directly from the phase shift of the strongest set of ionospheric waves. The power of these waves, which originated at Albuquerque, the local major power consumer, was 15.3 W, producing a power density of 0.018 W/m2. The calculated power density that should be generated from the local power generating stations around Albuquerque was also 0.018 W/m2, in agreement with the experimentally measured value. This correspondence shows that the power generated by power stations and being consumed is not lost but captured by the ionosphere.

Diffracted beam interferometry - Differential phase contrast image of an amorphous thin film material.

Differential phase contrast based on diffracted beam interferometry is used to explain the good phase contrast found of an amorphous thin film material deposited on the surface of a gold (Au) crystal substrate. An electron biprism is used to interfere two symmetrically diffracted beams generated by the Au crystal substrate that carried the phase of the amorphous material specimen. Bragg diffraction from the Au crystal substrate is used to explain why the phase of the amorphous thin film material is so well phase imaged. The phase of the amorphous material that was deposited on the specimen's upper surface of the Au crystal substrate is canceled and thus not revealed in the phase image whereas the phase due to the amorphous material deposited on the bottom surface of the Au crystal substrate does not cancel due to having a lateral phase shift in the amorphous material specimen plane proportional to the substrate thickness and Bragg angle of the diffracted beams. The lateral phase shift enabled differential phase contrast of the amorphous material specimen.

A high angle scattering, stable amorphous metal TEM specimen for measuring the information envelop of electron microscopes.

An amorphous metal (a-metal) TEM specimen suitable for measuring the information envelop of (S)TEM electron microscopes is presented. Its features include producing high angle electron scattering intensities and having good structural stability compared with commonly used specimens of amorphous carbon (a-C) and Au islands supported on a-C substrate.

Acid-treated Fe-doped TiO2 as a high performance photocatalyst used for degradation of phenol under visible light irradiation.

The photocatalytic activity of Fe-doped TiO2 nanoparticles is significantly increased by an acid-treatment process. The photocatalyst nanoparticles were prepared using sol-gel method with 0.5 mol% ratio of Fe:Ti in acidic pH of 3. The nanoparticles were structurally characterized by means of X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) and diffuse reflectance spectroscopy (DRS). It was observed that the photocatalytic activity suffered from an iron oxide contaminating layer deposited on the surface of the nanoparticles. This contamination layer was removed using an HCl acid-treatment process. The photocatalytic activity using 500 mg/L of Fe0.5-TiO2 in a 10 mg/L of phenol solution increased significantly from 33% to 57% (about 73% increase in the performance), within 90 min of reaction time under visible light irradiation. This significant improvement was achieved by removing the iron oxide contamination layer from the surface of the nanoparticles and adjusting pH to mild acidic and basic pHs.

Coherence of k-space electrons: application to TDS electrons by DBI.

Methods of controlled electron interference in k-space on the diffraction plane by means of an electron biprism invented during the Tonomura Electron Wavefront Project are briefly reviewed. The results presented show the partial coherence of self-interfered diffusely scattered electrons, elastically scattered and inelastically scattered, found outside and in between the Bragg diffracted beams often referred to as thermal diffuse scattering (TDS) of electrons. The interference fringes formed in the TDS intensity have been used to calculate a mean displacement of the atom of u ≈ 12 pm in Aluminum in the direction perpendicular to the Bragg planes.

Measurements validating the confocal scanning laser holography microscope.

A confocal scanning laser holography (CSLH) microscope that uniquely combines the concepts of confocal microscopy with holography has been validated for making nonintrusive, full three-dimensional (3D) intensity and phase measurements of objects from a single viewpoint of observation without loss of object information. The phase measurements have been used to determine the 3D refractive indices of a point source heated silicone oil. The refractive indices are converted to 3D temperature measurements, which are useful for heat transfer studies. An important feature of CSLH is its nonintrusive 3D scanning method, which enables its application to the study of Marangoni convection in microgravity with minimal operational vibrations affecting the motion of fluid in the specimen.

Coherent electron interference from amorphous TEM specimens.

For the first time, the electron intensity on the diffraction plane from amorphous transmission electron microscope (TEM) specimens has been found to have sufficient coherence to produce fringes in interferograms that were created using a wavefront splitting method of diffracted beam interferometry. The fringes were found to exist from low to high electron-scattering angles. Their spatial frequency depended on the angular overlap of the interfering beams, which was controlled by an electron biprism. From these interferograms, phase information of amorphous materials, which is information now lacking and required for determining their atomic structures, was obtained. An immediate application of this interference is a new method to determine the spatial resolution of the TEM that occurs at the shear angle for fringe disappearance.

Developing a confocal acoustic holography microscope for non-invasive 3D temperature and composition measurements.

A confocal acoustic holography microscope (CAHM) has been designed, simulated and partially verified experimentally to take holograms for non-invasive, three-dimensional measurements of a specimen's refractive indices from one view point. The designed and simulated prototype CAHM used a frequency of 2.25 MHz and measured sound speed changes of 16 m/s, temperature changes of 5 degrees C and had a spatial resolution of 660 microm. With future improvements utilizing the latest technologies such as two-dimensional array detectors, Micro-Electro-Mechanical Systems (MEMS), and acoustic lenses, resolutions of 1m/s, 0.5 degrees C, and 150 microm are expected. The CAHM is expected to have many useful applications, including non-invasive mass and heat transfer measurements in fluids and materials and as a medical diagnostic tool to non-intrusively visualize compositions and temperatures within the human body.

Electron beam coherence measurements using diffracted beam interferometry/holography.

The intensity and coherence of elastically and inelastically scattered electrons have been studied by the interference of electron-diffracted beams using a method of diffracted beam interferometry/holography (DBI/H). In the interferograms produced, fringes were found to exist from low to high scattering angles. The intensity and coherence of the fringes are useful for understanding the contrast mismatch between experimental and simulated images found in atomic resolution images of crystals produced by transmission electron microscopy (TEM) and annular dark-field (ADF) scanning transmission electron microscopy (STEM). The fringes disappear when the interfering beams are separated from an exact overlay position, which produces a measurement of the beam's lateral coherence and holds promise for measuring the coherence of the respective quasi-particles associated with the energy loss electrons.