Showing papers on "Radio wave published in 2011"

Encoding many channels in the same frequency through radio vorticity: first experimental test

Abstract: We have shown experimentally that it is possible to propagate and use the properties of twisted non-monochromatic incoherent radio waves to simultaneously transmit to infinity more radio channels on the same frequency band by encoding them in different orbital angular momentum states. This novel radio technique allows the implementation of, at least in principle, an infinite number of channels on one and the same frequency, even without using polarization or dense coding techniques. An optimal combination of all these physical properties and techniques represents a solution for the problem of radio band congestion. Our experimental findings show that the vorticity of each twisted electromagnetic wave is preserved after the propagation, paving the way for entirely new paradigms in radio communication protocols.

Sources: The optoelectronic oscillator

Abstract: Photonic technology can now be used to construct miniature sources of high-frequency radio waves that have exceptional spectral purity.

Observing pulsars and fast transients with LOFAR

Abstract: Low frequency radio waves, while challenging to observe, are a rich source of information about pulsars. The LOw Frequency ARray (LOFAR) is a new radio interferometer operating in the lowest 4 octaves of the ionospheric "radio window": 10-240 MHz, that will greatly facilitate observing pulsars at low radio frequencies. Through the huge collecting area, long baselines, and flexible digital hardware, it is expected that LOFAR will revolutionize radio astronomy at the lowest frequencies visible from Earth. LOFAR is a next-generation radio telescope and a pathfinder to the Square Kilometre Array (SKA), in that it incorporates advanced multi-beaming techniques between thousands of individual elements. We discuss the motivation for low-frequency pulsar observations in general and the potential of LOFAR in addressing these science goals. We present LOFAR as it is designed to perform high-time-resolution observations of pulsars and other fast transients, and outline the various relevant observing modes and data reduction pipelines that are already or will soon be implemented to facilitate these observations. A number of results obtained from commissioning observations are presented to demonstrate the exciting potential of the telescope. This paper outlines the case for low frequency pulsar observations and is also intended to serve as a reference for upcoming pulsar/fast transient science papers with LOFAR.

Method and system for wireless charging using radio wave

Abstract: A method and system for wireless charging using a radio wave. The method includes scanning a radio wave of an access point, determining an available charging frequency band among frequency bands, sending the access point a request for transmitting a charging radio wave at the charging frequency band, and switching power output from an antenna, to a battery circuit.

Moving Object, Wireless Power Feeding System, and Wireless Power Feeding Method

Abstract: An object is to provide a moving object structure capable of reducing power loss caused when power is supplied from a power feeding device to a moving object by wireless communication. Another object is to provide a moving object structure capable of reducing the strength of a radio wave radiated to the surroundings. Before power is supplied to a moving object, a radio wave for alignment of antennas is output from a power feeding device. That is, radio waves are output from a power feeding device in two stages. In a first stage, a radio wave is output to align positions of antennas of the power feeding device and the moving object. In a second stage, a radio wave is output to supply power from the power feeding device to the moving object.

Artificial small‐scale field‐aligned irregularities in the high latitude F region of the ionosphere induced by an X‐mode HF heater wave

Abstract: [1] The effects on the high-latitude F region of the ionosphere by X-mode powerful HF radio waves injected towards the magnetic zenith (MZ) are analysed. The experiments were conducted using the EISCAT/Heating facility and UHF radar at Tromso, Norway, the CUTLASS (SuperDARN) radar and the EISCAT ionosonde (dynasonde). The results show that the X-mode HF pump wave, radiated into the magnetic zenith from the HF heater, can generate very strong small-scale artificial field aligned irregularities (AFAIs) in the F-region of the high-latitude ionosphere. These irregularities, with spatial scales across the geomagnetic field of the order of 8–15 m, are generated when the heater frequency is above the ordinary-mode critical frequency but comparable with the extraordinary-mode critical frequency. The generation of the X-mode AFAIs was accompanied by electron temperature (Te) enhancements up to 50% above the background level and an increase in the electron density (Ne) by up to 30%.

Multiple phase screen modeling of ionospheric scintillation along radio occultation raypaths

Abstract: [1] We present the Radio Occultation Scintillation Simulator (ROSS), which uses the multiple phase screen method (MPS) to simulate the forward scatter of radio waves by irregularities in the equatorial ionosphere during radio occultation experiments. ROSS simulates propagation through equatorial plasma bubbles which are modeled as homogeneous electron density fluctuations modulated by a Chapman profile in altitude and a Gaussian window in the magnetic east-west direction. We adjust the parameters of the density model using electron density profiles derived from the ALTAIR incoherent scatter radar (9.4°N, 167.5°E, 4.3° north dip), and space-to-ground observations of scintillation using VHF and GPS receivers that are colocated with the radar. We compare the simulated occultation scintillation to observations of scintillation from the CORISS instrument onboard the C/NOFS satellite during a radio occultation occurring near ALTAIR on 21 April 2009. The ratio of MPS predicted S4 to CORISS observed S4 throughout the F region altitudes of 240–350 km ranged between 0.86 and 1.14.

BioRadioTransmitter: A Self-Powered Wireless Glucose-Sensing System

Abstract: Background: Although an enzyme fuel cell can be utilized as a glucose sensor, the output power generated is too low to power a device such as a currently available transmitter and operating system, and an external power source is required for operating an enzyme-fuel-cell-based biosensing system. We proposed a novel biosensor that we named BioCapacitor, in which a capacitor serves as a transducer. In this study, we constructed a new BioCapacitorbased system with an added radio-transmitter circuit and a miniaturized enzyme fuel cell. Methods: A miniaturized direct-electron-transfer-type compartmentless enzyme fuel cell was constructed with flavin adenine dinucleotide-dependent glucose dehydrogenase complex-based anode and a bilirubin-oxidase-based cathode. For construction of a BioRadioTransmitter wireless sensing system, a capacitor, an ultra-low-voltage chargepump-integrated circuit, and Hartley oscillator circuit were connected to the miniaturized enzyme fuel cell. A radio-receiver circuit, comprising two field-effect transistors and a coil as an antenna, was used to amplify the signal generated from the biofuel cells. Results: Radio wave signals generated by the BioRadioTransmitter were received, amplified, and converted from alternate to direct current by the radio receiver. When the capacitor discharges in the presence of glucose, the BioRadioTransmitter generates a radio wave, which is monitored by a radio receiver connected wirelessly to the sensing device. Magnitude of the radio wave transmission frequency change observed at the radio receiver was correlated to glucose concentration in the fuel cells. Conclusions: We constructed a stand-alone, self-powered, wireless glucose-sensing system called a BioRadioTransmitter by using a radio transmitter in which the radio wave transmission frequency changes with the glucose concentration in the fuel cell. The BioRadioTransmitter is a significant advance toward construction of an implantable continuous glucose monitor.

A vlba search for binary black holes in active galactic nuclei with double-peaked optical emission line spectra

Abstract: We have examined a subset of 11 active galactic nuclei (AGNs) drawn from a sample of 87 objects that possess double-peaked optical emission line spectra, as put forward by Wang et al. and are detectable in the Faint Images of the Radio Sky at Twenty-centimeters (FIRST) survey at radio wavelengths. The double-peaked nature of the optical emission line spectra has been suggested as evidence for the existence of binary black holes in these AGNs, although this interpretation is controversial. We make a simple suggestion that direct evidence of binary black holes in these objects could be searched for in the form of dual sources of compact radio emission associated with the AGNs. To explore this idea, we have used the Very Long Baseline Array to observe these 11 objects from the Wang et al. sample. Of the 11 objects, we detect compact radio emission from two, SDSS J151709+335324 and SDSS J160024+264035. Both objects show single components of compact radio emission. The morphology of SDSS J151709+335324 is consistent with a recent comprehensive multi-wavelength study of this object by Rosario et al. Assuming that the entire sample consists of binary black holes, we would expect of order one double radio core to be detected, based on radio wavelength detection rates from FIRST and very long baseline interferometry surveys. We have not detected any double cores, thus this work does not substantially support the idea that AGNs with double-peaked optical emission lines contain binary black holes. However, the study of larger samples should be undertaken to provide a more secure statistical result, given the estimated detection rates.

Observation of planetary radio emissions using large arrays

Abstract: [1] Planetary radio astronomy mostly concerns plasma phenomena at low frequencies (i.e., below a few hundred MHz). The low frequency limit for ground-based observations of these phenomena is given by the Earth's ionosphere, which limits ground based radio observations to frequencies ≥10 MHz. We give an overview and update on the status of a few representative ground-based radio arrays that have been used for planetary studies within the frequency range 10–200 MHz, and we discuss their potential for the four types of planetary radio emissions that can be observed within this frequency range: (1) synchrotron emission from Jupiter's radiation belts, (2) radio bursts caused by solar system planetary lightning, (3) Jupiter's magnetospheric emission, and (4) magnetospheric radio emission from extrasolar planets, for which we also give an update to previous predictive studies. Comparing the four emission modes with the characteristics of existing ground-based radio arrays, we show that the Low Frequency Array (LOFAR) has the potential to bring considerable advances to those four fields of planetary radio science.

Simultaneous x-ray and radio observations of young stellar objects in ngc 1333 and ic 348

Abstract: Young stellar objects (YSOs) and in particular protostars are known to show a variety of high-energy processes. Observations in the X-ray and centimetric radio wavelength ranges are thought to constrain some of these processes, e.g., coronal-type magnetic activity. There is a well-known empirical correlation of radio and X-ray luminosities in active stars, the so-called Gudel-Benz (GB) relation. Previous evidence of whether YSOs are compatible with this relation remains inconclusive for the earliest evolutionary stages. The main difficulty is that due to the extreme variability of these sources, simultaneous observations are essential. Until now, only a few YSOs and only a handful of protostars have been observed simultaneously in the X-ray and radio range. To expand the sample, we have obtained such observations of two young clusters rich in protostars, NGC 1333 and IC 348. While the absolute sensitivity is lower for these regions than for more nearby clusters like CrA, we find that even in deep continuum observations carried out with the NRAO Very Large Array (VLA), the radio detection fraction for protostars in these clusters is much lower than the X-ray detection fraction. Very few YSOs are detected in both bands, and we find the radio and X-ray populations among YSOs to be largely distinct. We combine these new results with previous simultaneous Chandra and VLA observations of star-forming regions and find that YSOs with detections in both bands appear to be offset toward higher radio luminosities for given X-ray luminosities when compared with the GB relation, although even in this sensitive data set most sources are too weak for the radio detections to provide information on the emission processes. The considerably improved sensitivity of the Expanded VLA will provide a better census of the YSO radio population as well as better constraints on the emission mechanisms.

Atmospheric Refraction and Propagation in Lower Troposphere

Abstract: Influence of atmospheric refraction on the propagation of electromagnetic waves has been studied from the beginnings of radio wave technology (Kerr, 1987). It has been proved that the path bending of electromagnetic waves due to inhomogeneous spatial distribution of the refractive index of air causes adverse effects such as multipath fading and interference, attenuation due to diffraction on the terrain obstacles or so called radio holes (Lavergnat & Sylvain, 2000). These effects significantly impair radio communication, navigation and radar systems. Atmospheric refractivity is dependent on physical parameters of air such as pressure, temperature and water content. It varies in space and time due the physical processes in atmosphere that are often difficult to describe in a deterministic way and have to be, to some extent, considered as random with its probabilistic characteristics. Current research of refractivity effects utilizes both the experimental results obtained from in situ measurements of atmospheric refractivity and the computational methods to simulate the refractivity related propagation effects. The two following areas are mainly addressed. First, a more complete statistical description of refractivity distribution is sought using the finer space and time scales in order to get data not only for typical current applications such as radio path planning, but also to describe adverse propagation in detail. For example, multipath propagation can be caused by atmospheric layers of width of several meters. During severe multipath propagation conditions, received signal changes on time scales of minutes or seconds. Therefore, for example, the vertical profiles of meteorological parameters measured every 6 hours by radiosondes are not sufficient for all modelling purposes. The second main topic of an ongoing research is a development and application of inverse propagation methods that are intended to obtain refractivity fields from electromagnetic measurements. In the chapter, recent experimental and modelling results are presented that are related to atmospheric refractivity effects on the propagation of microwaves in the lowest troposphere. The chapter is organized as follows. Basic facts about atmospheric refractivity are introduced in the Section 2. The current experimental measurement of the vertical distribution of refractivity is described in the Section 3. Long term statistics of atmospheric refractivity parameters are presented in the Section 4. Finally, the methods of propagation modelling of EM waves in the lowest troposphere with inhomogeneous refractivity are discussed in the Section 5.

Exploiting radio irregularity in the Internet of Things for automated people counting

Abstract: The Internet of Things (IoT) is a new concept that refers to an Internet connecting not just computer systems but a plethora of systems, devices, and objects, collectively referred to as “Things”, and encompasses technologies for identification and tracking, sensing and actuation, both wired and wireless communications, and also, intelligence and cognition. Wireless communications, which is an integral part of IoT, suffers from radio irregularity - a phenomenon referring to radio waves being selectively absorbed, reflected or scattered by objects in their paths, e.g., human bodies that comprises liquid, bone and flesh. Radio irregularity is often regarded as a problem in wireless communications but, with the envisioned pervasiveness of IoT, we aim to exploit radio irregularity as a means to detect people. We demonstrate how radio signal fluctuations arising from radio irregularity can be used to provide a low-cost alternative to dedicated sensing systems for indoor automated people counting.

Wireless communication system

Abstract: PROBLEM TO BE SOLVED: To easily enhance a reception level of a reader on the ground to receive a radio wave transmitted from a wireless tag in a manhole.SOLUTION: A radio wave reflecting member 515 is installed across a whole surface of a floor 510 of a manhole 500 so as to reflect a radio wave. The radio wave reflecting member 515 is made of metal mesh material or reflective coating material, etc. The metal mesh material is made of meshes each of which has a length shorter than that of the radio wave, is foldable so as to be carried into the manhole 500 before installation without causing any inconvenience, and can be spread over the floor 510 of the manhole 500 at the time of installation. The radio wave of the wireless tag 100 mounted in the manhole 500 is reflected on the floor 510 where the radio wave reflecting member 515 is installed, and is transmitted along with a direct wave to a reader 200 on the ground (road).

Modelling and analysis of radio tomography

Abstract: Radio tomographic imaging (RTI) has recently been proposed for tracking object location via radio waves without requiring the objects to transmit or receive radio signals. The position is extracted by inferring which voxels are obstructing a subset of radio links in a dense wireless sensor network. This paper proposes a refined model for signal attenuation in RTI based on measured data, which is used to provide analytic support for previous qualitative observations. We also provide an analytic method for choosing the weighting of the regularization term, and investigate methods for dealing with negative observations caused by noise.

Radio communication system, radio resource determination method therefor, communication management device, and control method and control program for communication management device

Abstract: In order to effectively determine an optimized radio resource, a radio communication system ( 100 ) includes a plurality of first base stations ( 111 ) and a plurality of first mobile stations ( 112 ) respectively connected to the plurality of first base stations ( 111 ). In the radio communication system ( 100 ), there are included calculation means ( 103 ) for calculating a statistic ( 130 ) by aggregating interference levels of radio waves between the plurality of first base stations ( 111 ) and second mobile stations ( 122 ) connected to a second base station ( 121 ) that forms a second cell ( 120 ) larger than a first cell ( 110 ) formed by each of the first base stations ( 111 ); and determination means ( 104 ) for determining, based on the statistic ( 130 ), a radio resource to be used by the plurality of first base stations ( 111 ) or the plurality of first mobile stations ( 112 ).

A VLBA search for binary black holes in active galactic nuclei with double-peaked optical emission line spectra

Abstract: We have examined a subset of 11 active galactic nuclei (AGN) drawn from a sample of 87 objects that possess double-peaked optical emission line spectra, as put forward by Wang et al (2009a) and are detectable in the FIRST survey at radio wavelengths The double-peaked nature of the optical emission line spectra has been suggested as evidence for the existence of binary black holes in these AGN, although this interpretation is controversial We make a simple suggestion, that direct evidence of binary black holes in these objects could be searched for in the form of dual sources of compact radio emission associated with the AGN To explore this idea, we have used the Very Long Baseline Array to observe these 11 objects from the Wang et al (2009a) sample Of the 11 objects, we detect compact radio emission from two, SDSS J151709+335324 and SDSS J160024+264035 Both objects show single components of compact radio emission The morphology of SDSS J151709+335324 is consistent with a recent comprehensive multi-wavelength study of this object by Rosario et al (2010) Assuming that the entire sample consists of binary black holes, we would expect of order one double radio core to be detected, based on radio wavelength detection rates from FIRST and VLBI surveys We have not detected any double cores, thus this work does not substantially support the idea that AGN with double-peaked optical emission lines contain binary black holes However, the study of larger samples should be undertaken to provide a more secure statistical result, given the estimated detection rates

Dusty space plasma diagnosis using temporal behavior of polar mesospheric summer echoes during active modification

Abstract: . The objective of this paper is to study the effect of different plasma and dust parameters on Polar Mesospheric Summer Echoes (PMSE) temporal behavior after turn-on and turn-off of radio wave heating and to use these responses to diagnose the properties of the dust layer. The threshold radar frequency and dust parameters for the enhancement or suppression of radar echoes after radio wave heating turn-on are investigated for measured mesospheric plasma parameters. The effect of parameters such as the electron temperature enhancement during heating, dust density, dust charge polarity, ion-neutral collision frequency, electron density and dust radius on the temporal evolution of electron irregularities associated with PMSE are investigated. The possible diagnostic information for various charged dust and background plasma quantities using the temporal behavior of backscattered radar power in active experiments is discussed. The computational results are used to make predictions for PMSE active modification experiments at 7.9, 56, 139, 224 and 930 MHz corresponding to existing radar facilities. Data from a 2009 VHF (224 MHz) experiment at EISCAT is compared with the computational model to obtain dust parameters in the PMSE.

Remote sensing planetary waves in the midlatitude mesosphere using low frequency transmitter signals

Abstract: . Very low and low radio frequency (VLF/LF) propagation responds sensitively to the electron density distribution in the lower ionosphere (upper mesosphere). Whereas propagation paths crossing subpolar and polar regions are frequently affected by forcing from above by particle precipitations, mid- and lowlatitude paths let forcing from below be more prominent. Our observations (2009–2011) show, that the low frequency propagation conditions along the midlatitude path from Sicily to Germany (52° N 8° E) using the NSY 45.9 kHz transmitter (37° N 14° E) prove to be a good proxy of mesosphere planetary wave activity along the propagation path. High absorption events with VLF/LF propagation correlate to the well known winter time D-layer anomaly observed with high frequency (HF) radio waves. VLF/LF propagation calculations are presented which show that the radio signal amplitude variations can be modeled by planetary wave modulated collison frequency and electron density profiles. The other way around wave pressure amplitudes can be inferred from the VLF/LF data.

Long Distance Propagation of HF Radio Waves

Abstract: 1 Introduction.- 1.1 Very Long-Distance and Magnetospheric Propagation.- 1.1.1 Round-the-World Signals.- 1.1.2 Long-Distance Oblique Sounding.- 1.1.3 Magnetospheric Propagation.- 1.2 Features of Radio Wave Propagation over Long Distances.- 2 Spherically-Symmetric Ionosphere.- 2.1 Wave Equation in the Spherically-Symmetric Ionosphere Ionospheric Wave Ducts.- 2.2 Radio Wave Field in an Ionospheric Duct.- 2.3 Radio Wave Tunneling through the Interduct Barriers Capture Coefficient.- 2.4 Ray Trajectories Pulse Propagation.- 3 Horizontally-Inhomogeneous Ionosphere.- 3.1 Geometrical Optics.- 3.2 Adiabatic Approximation.- 3.3 Lateral Deviations of the Radio Wave Trajectories Bearing Variation.- 3.4 Capture of Radio Waves into the Interlayer Ionospheric Duct and Their Escape from the Duct.- 4 Regularities of Very Long-Distance Radio Wave Propagation in the Ionosphere.- 4.1 Investigations of the Global Characteristics of Long-Distance Propagation.- 4.2 Radio Wave Absorption.- 5 Calculation of Long-Distance Radio Paths.- 5.1 Radio Path Calculation with a Parabolic Model of the Ionosphere.- 5.2 Calculation of Long-Distance Radio Paths, Using the Complex Ionospheric Model.- 5.3 Comparison of the Adiabatic Approximation with the Ray-Tracing Techniques.- 6 Radio Wave Scattering.- 6.1 Effect of Scattering on the Capture of Radio Waves into the Interlayer Duct.- 6.2 Effect of Multiple Scattering on Radio Wave Propagation in a Duct.- 6.3 Signal Fluctuations in the Reception Point.- 7 Nonlinear Phenomena.- 7.1 Regular Nonlinear Refraction.- 7.2 Nonlinear Radio Wave Scattering.- 7.2.1 Character of Irregular Plasma Density Perturbations.- 7.2.2 Influence of Nonlinear Scattering on Radio Wave Capture into IWD and Departure from the Duct.- 7.2.3 Effect of Nonlinear Scattering on Long-Distance Radio Propagation.- 8 Radio Wave Propagation in the Magnetosphere.- 8.1 Electromagnetic Wave Guiding by Weak Waveguides.- 8.2 HF Radio Waves in the Magnetospheric Ducts.- Appendix 1 Wave Equation. Radio Wave Field Distribution in Connected Waveguide Ducts.- A1.1 Wave Equation.- A1.2 Radio Wave Field Distribution in Connected Waveguide Ducts.- Appendix 2 Analytical Models of Ionospheric Parameters.- A2.1 Three-Dimensional Equinoctial Model of Electron Density in the Ionosphere.- A2.2 Three-Dimensional Equinoctial Model of Electron Effective Collision Frequency.- Appendix 3 Wave Theory of HF Radio Wave Propagation in a Horizontally-Inhomogeneous Ionosphere (N. D. Borisov and A.V. Gurevich).- A3.1 Wave Propagation in a Slightly Inhomogeneous Ionosphere.- A3.2 Quasispherical Approximation.- A3.3 Interaction of Quasispherical Modes in the Real Ionosphere.- A3.4 Adiabatic Modes of Ionospheric Waveguides.- A3.5 Radio Wave Capture into IWD.- A3.5.1 Neighborhood of the Separatrix.- A3.5.2 Antenna Radiation Field.- A3.5.3 Radio Wave Capture into a Duct. Role of Wave Effects.- Principal Symbols.- List of Abbreviations.- References.

Peak electron densities in Saturn's ionosphere derived from the low-frequency cutoff of Saturn lightning

Abstract: Radio bursts from Saturn lightning have been observed by the Cassini Radio and Plasma Wave Science instrument at frequencies of a few megahertz during several month-long storms since 2004. As the radio waves traverse Saturn's ionosphere on their way to the spacecraft, one can determine the peak electron density from the measurement of the low-frequency cutoff below which the radio bursts are not detected. In this way we obtained 231 profiles of peak electron densities that cover all Saturnian local times at a kronocentric latitude of 35°S, where the storms were spotted by the Cassini camera. Peak electron densities show a large variation at dawn and dusk and are around 5 × 10^4 cm^(−3), in fair agreement with radio occultation measurements at midlatitudes. At noon and midnight, the densities are typically somewhat above 10^5 cm^(−3) and around 10^4 cm^(−3), respectively. The diurnal variation is about 1 to 2 orders of magnitude for averaged profiles over one storm at 35°S. This is somewhat less compared to previous Voyager measurements which showed more than 2 orders of magnitude variation. The diurnal variation as well as the peak electron densities of Saturn's ionosphere tend to decrease with the decreasing solar EUV flux from 2004 until the end of 2009.

Efficient Rasterization for Outdoor Radio Wave Propagation

Abstract: Conventional beam tracing can be used for solving global illumination problems It is an efficient algorithm and performs very well when implemented on the GPU This allows us to apply the algorithm in a novel way to the problem of radio wave propagation The simulation of radio waves is conceptually analogous to the problem of light transport We use a custom, parallel rasterization pipeline for creation and evaluation of the beams We implement a subset of a standard 3D rasterization pipeline entirely on the GPU, supporting 2D and 3D frame buffers for output Our algorithm can provide a detailed description of complex radio channel characteristics like propagation losses and the spread of arriving signals over time (delay spread) Those are essential for the planning of communication systems required by mobile network operators For validation, we compare our simulation results with measurements from a real-world network Furthermore, we account for characteristics of different propagation environments and estimate the influence of unknown components like traffic or vegetation by adapting model parameters to measurements

Reconstruction of Complicated Movement of Part of the Human Body Using Radio Wave Autodyne Signal

Abstract: Biometric parameters of movement of the human body were studied. The parameters related to respiration and heart contraction were tested using radio wave-probing methods with a radio wave interferometer based on an autodyne HSF generator on a Gunn diode. In contrast to the literature, this work approximates human body movement using a non-harmonic periodic function.

Emission kinetics of light, sound, and radio waves from single-crystalline quartz after impact on its surface

Abstract: A steel striker impacting the surface of single-crystalline quartz generates strain waves and their related acoustic and electromagnetic emissions. Simultaneously, microcracks with free excited SiO• radicals at their edges appear in the single crystal. The relaxation of the electronic excitation causes bursts of fractoluminescence. The intensity of the bursts is proportional to the microcrack surface area. It is found that the linear sizes of microcracks vary from 15 to 70 μm. Cracking changes the slope of the time dependences of the acoustic and electromagnetic emission intensities. The microcrack size distribution obeys a power law with an exponent of about two.

Moving object, and system and method for wireless power feeding

Abstract: PROBLEM TO BE SOLVED: To provide a moving object structure capable of reducing power loss caused when power is supplied from a power feeding device to a moving object by wireless communication, and reducing the intensity of radio waves radiated to the surroundings. SOLUTION: A moving object having a plurality of antennas receives radio waves transmitted from a power feeding device. At least one of the plurality of antennas is installed apart from the other antenna(s) of the moving object. Then, the radio waves transmitted from the power feeding device are received by all the plurality of antennas and converted into electric energy. Alternatively, the radio waves transmitted from the power feeding device are received by any one or more antennas selected from the plurality of antennas and converted into electric energy. COPYRIGHT: (C)2011,JPO&INPIT

Plasma Expansion From a Radio Frequency Microdischarge

Abstract: Plasma expansion of a capacitively coupled radio frequency (13.56 MHz) argon microdischarge into a larger glass tube is studied by acquisition and analysis of high-resolution digital images. The microdischarge operating conditions are a flow of about 1.5 L/min, a pressure of 7 torr, and a power of 10 W. Interesting plume patterns can be generated, and an example of plasma striations within the plume is shown.

Spectrum evolution in binary pulsar B1259−63/LS 2883 Be star and gigahertz‐peaked spectra

Abstract: We study the radio spectrum of PSR B1259−63 orbiting around the Be star LS 2883 and show that the shape of the spectrum depends on the orbital phase. At frequencies below 3 GHz, PSR B1259−63 flux densities are lower when measured near the periastron passage than those measured far from periastron. We suggest that an interaction of the radio waves with the Be star environment accounts for this effect. While it is quite natural to explain the pulsar eclipse by the presence of an equatorial disc around LS 2883, this disc alone cannot be responsible for the observed spectral evolution of PSR B1259−63 and we, therefore, propose a qualitative model which explains this evolution. We consider two mechanisms that might influence the observed radio emission: free–free absorption and cyclotron resonance. We believe that this binary system can hold the clue to the understanding of gigahertz-peaked spectra of pulsars.

Signal transmission apparatus, electronic instrument and signal transmission method

Abstract: A signal transmission apparatus includes: a transmission section adapted to transmit a transmission object signal as a radio wave; a reception section adapted to receive the radio wave transmitted from the transmission section and output an electric signal corresponding to the received radio wave; and a connection section adapted to connect a first housing and a second housing of an electronic instrument pivotably around a center axis; the connection section having a radio signal transmission line formed therein by which wireless transmission can be carried out between the transmission section and the reception section.