WorldWideScience

Sample records for frequency transformer linked

  1. Advanced High Power DC-DC Converter using A Novel Type Voltage Source Full-Bridge Soft-Switching PWM Inverter with High Frequency Transformer Link for Arc Welding Applications

    Science.gov (United States)

    Morimoto, Keiki; Doi, Toshimitsu; Manabe, Haruhiko; Ahmed, Tarek; Hiraki, Eiji; Lee, Hyun-Woo; Nakaoka, Mutsuo

    This paper presents a new circuit topology of full-bridge soft-switching PWM inverter linked DC-DC power converter composed of conventional full-bridge high frequency PWM inverter with high frequency transformer and an active quasi-resonant snubber consisting of an additional power switching device in series with DC busline and a lossless capacitor in parallel with DC busline. Under this proposed high frequency soft-switching PWM inverter linked DC-DC converter, four power switches in the full-bridge arms and DC busline series switch can achieve ZVS at turn-off commutation. By developing the advanced soft-switching PWM high frequency inverter type DC-DC converter, although the conduction power loss of DC busline series power switch increases a little, the total turn-off switching loss of full-bridge high frequency inverter power modules can be sufficiently lowered more and more in the higher frequency range of 60kHz. As a result, when the switching frequency of high frequency inverter power stage using IGBT power modules is designed so as to be more than about 10kHz, the more the switching frequency of inverter increases, the more this high frequency soft-switching DC-DC converter has remarkable advantage as for the power conversion efficiency as compared with the conventional hard-switching PWM inverter DC-DC converter. Its practical effectiveness of high power density and high performance is actually proved for TIG arc welding equipment in industry.

  2. Wideband FM Demodulation and Multirate Frequency Transformations

    Science.gov (United States)

    2016-12-15

    the center frequency and bandwidth are manually assigned to each formant, which may incur serious distortion to the isolated resonance signal and... problem can be solved via populating the whole time- frequency space to take advantage of the dyadic filter bank behavior of the EMD. Currently, we only...AFRL-RV-PS- AFRL-RV-PS- TR-2016-0123 TR-2016-0123 WIDEBAND FM DEMODULATION AND MULTIRATE FREQUENCY TRANSFORMATIONS Balu Santhanam and Wenjing Liu

  3. Electrocardiogram Signal and Linear Time-Frequency Transforms

    Science.gov (United States)

    Krishna, B. T.

    2014-12-01

    The diagnostic analysis of non-stationary multi component signals such as electrocardiogram (ECG) involves the use of time-frequency transforms. So, the application of time-frequency transforms to an ECG signal is an important problem of research. In this paper, initially, linear transforms like short time Fourier transform, continuous wavelet transforms, s-transform etc. are revisited. Then the application of these transforms to normal and abnormal ECG signals is illustrated. It has been observed that s-transform provides better time and frequency resolution compared to other linear transforms. The fractional Fourier transform provides rotation to the spectrogram representation.

  4. Linking transformational leadership and organisation commitment

    OpenAIRE

    Rua, Orlando Manuel Lima; Araújo, João

    2014-01-01

    The main goal of this paper is to analyse the impacts of transformational leadership on organisational commitment. To this effect we developed a case study following a quantitative methodological approach. The research was conducted at the Serralves Foundation (Porto, Portugal) to empirically test the proposed research model and its hypothesis. The empirical results confirm that transformational leadership are not significantly influenced by commitment. As the main limitation of this...

  5. Transformer Model in Wide Frequency Bandwidth for Power Electronics Systems

    Directory of Open Access Journals (Sweden)

    Carlos Gonzalez-Garcia

    2013-01-01

    Full Text Available The development of the smart grids leads to new challenges on the power electronics equipment and power transformers. The use of power electronic transformer presents several advantages, but new problems related with the application of high frequency voltage and current components come across. Thus, an accurate knowledge of the transformer behavior in a wide frequency range is mandatory. A novel modeling procedure to relate the transformer physical behavior and its frequency response by means of electrical parameters is presented. Its usability is demonstrated by an example where a power transformer is used as filter and voltage reducer in an AC-DC-AC converter.

  6. Speaker Identification using Frequency Dsitribution in the Transform Domain

    Directory of Open Access Journals (Sweden)

    Dr. H B Kekre

    2012-02-01

    Full Text Available In this paper, we propose Speaker Identification using the frequency distribution of various transforms like DFT (Discrete Fourier Transform, DCT (Discrete Cosine Transform, DST (Discrete Sine Transform, Hartley, Walsh, Haar and Kekre transforms. The speech signal spoken by a particular speaker is converted into frequency domain by applying the different transform techniques. The distribution in the transform domain is utilized to extract the feature vectors in the training and the matching phases. The results obtained by using all the seven transform techniques have been analyzed and compared. It can be seen that DFT, DCT, DST and Hartley transform give comparatively similar results (Above 96%. The results obtained by using Haar and Kekre transform are very poor. The best results are obtained by using DFT (97.19% for a feature vector of size 40.

  7. Experimental radio frequency link for Ka-band communications applications

    Science.gov (United States)

    Fujikawa, Gene; Conray, Martin J.; Saunders, Alan L.; Pope, Dale E.

    1988-01-01

    An experimental radio frequency link has been demonstrated to provide two-way communication between a remote user ground terminal and a ground-based Ka-band transponder. Bit-error-rate performance and radio frequency characteristics of the communication link were investigated.

  8. High-Frequency Link Inverter for Fuel Cells Based on Multiple-Carrier PWM

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    HIGH-FREQUENCY (I-IF) ac link inverter topologies, with or without soft switching, have important practical advantages compared to more conventional dc link inverters in terms of isolation, size of magnetics, and other properties. It is possible to obtain these basic advantages directly in a conventional PWM inverter with trans former-coupled output, but only if the transformer can handle the low modulating frequency. HF link topologies have not been common for medium power (1 to 20kW), largely because of the number of power stages and control complexity.

  9. Transformer-based design techniques for oscillators and frequency dividers

    CERN Document Server

    Luong, Howard Cam

    2016-01-01

    This book provides in-depth coverage of transformer-based design techniques that enable CMOS oscillators and frequency dividers to achieve state-of-the-art performance.  Design, optimization, and measured performance of oscillators and frequency dividers for different applications are discussed in detail, focusing on not only ultra-low supply voltage but also ultra-wide frequency tuning range and locking range.  This book will be an invaluable reference for anyone working or interested in CMOS radio-frequency or mm-Wave integrated circuits and systems.

  10. Curvelet Transform-Based Denoising Method for Doppler Frequency Extraction

    Institute of Scientific and Technical Information of China (English)

    HOU Shu-juan; WU Si-liang

    2007-01-01

    A novel image denoising method based on curvelet transform is proposed in order to improve the performance of Doppler frequency extraction in low signal-noise-ratio (SNR) environment. The echo can be represented as a gray image with spectral intensity as its gray values by time-frequency transform. And the curvelet coefficients of the image are computed. Then an adaptive soft-threshold scheme based on dual-median operation is implemented in curvelet domain. After that, the image is reconstructed by inverse curvelet transform and the Doppler curve is extracted by a curve detection scheme. Experimental results show the proposed method can improve the detection of Doppler frequency in low SNR environment.

  11. Spectral density correction of a signal at frequency variable transformation

    Directory of Open Access Journals (Sweden)

    Viorel NICOLAU

    2006-12-01

    Full Text Available The goal of this paper is to determine analytical expression for the spectral density function of a signal, affected by a known frequency transformation, which do not modify the process energy. Such transformations of frequency variable can frequently appear on spectral density function of a signal, due to physical events (e.g. Doppler effect or mathematical considerations (e.g. changing the coordinate system. In this case, all components of the spectral density function are modified. The formulas are valid for every spectral component and can be used in signal processing, for model simulation or implementation of advanced algorithm. A case study is illustrated on wave spectrum correction.

  12. High frequency modeling of power transformers. Stresses and diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Bjerkan, Eilert

    2005-05-15

    In this thesis a reliable, versatile and rigorous method for high frequency power transformer modeling is searched and established. The purpose is to apply this model to sensitivity analysis of FRA (Frequency Response Analysis) which is a quite new diagnostic method for assessing the mechanical integrity of power transformer windings on-site. The method should be versatile in terms of being able to estimate internal and external over voltages and resonances. Another important aspect is that the method chosen is suitable for real transformer geometries. In order to verify the suitability of the model for real transformers, a specific test-object is used. This is a 20MVA transformer, and details are given in chapter 1.4. The high frequency power transformer model is established from geometrical and constructional information from the manufacturer, together with available material characteristics. All circuit parameters in the lumped circuit representation are calculated based on these data. No empirical modifications need to be performed. Comparison shows capability of reasonable accuracy in the range from 10 khz to 1 MHz utilizing a disc-to-disc representation. A compromise between accuracy of model due to discretization and complexity of the model in a turn-to-turn representation is inevitable. The importance of the iron core is emphasized through a comparison of representations with/without the core included. Frequency-dependent phenomena are accurately represented using an isotropic equivalent for windings and core, even with a coarse mesh for the FEM-model. This is achieved through a frequency-dependent complex permeability representation of the materials. This permeability is deduced from an analytical solution of the frequency-dependent magnetic field inside the conductors and the core. The importance of dielectric losses in a transformer model is also assessed. Since published data on the high frequency properties of press board are limited, some initial

  13. Time-frequency representation measurement based on temporal Fourier transformation

    Science.gov (United States)

    Suen, Yifan; Xiao, Shaoqiu; Hao, Sumin; Zhao, Xiaoxiang; Xiong, Yigao; Liu, Shenye

    2016-10-01

    We propose a new scheme to physically realize the short-time Fourier transform (STFT) of chirped optical pulse using time-lens array that enables us to get time-frequency representation without using FFT algorithm. The time-lens based upon the four-wave mixing is used to perform the process of temporal Fourier transformation. Pump pulse is used for both providing the quadratic phase and being the window function of STFT. The idea of STFT is physically realized in our scheme. Simulations have been done to investigate performance of the time-frequency representation scheme (TFRS) in comparison with STFT using FFT algorithm. Optimal measurement of resolution in time and frequency has been discussed.

  14. Ultrasonic transformation of micelle structures: effect of frequency and power.

    Science.gov (United States)

    Yusof, Nor Saadah Mohd; Ashokkumar, Muthupandian

    2015-05-01

    A comprehensive investigation on the effect of ultrasonic frequency and power on the structural transformation of CTABr/NaSal micelles has been carried out. Sonication of this micelle system at various ultrasonic frequencies and power resulted in the formation and separation of two types of micelles. High viscoelastic threadlike micelles of ∼ 2 nm in diameter and several μm in length and tubular micelles possessing a viscosity slightly above that of water with ∼ 30-50 nm diameter and few hundred nm length. The structural transformation of micelles was induced by the shear forces generated during acoustic cavitation. At a fixed acoustic power of 40 W, the structural transformation was found to decrease from 211 to 647 kHz frequency due to the decreasing shear forces generated, as evidenced by rheological measurements and cryo-TEM images. At 355 kHz, an increase in the structural transformation was observed with an increase in acoustic power. These findings provide a knowledge base that could be useful for the manipulation of viscosity of micelles that may have applications in oil industry.

  15. Frequency-Domain Maximum-Likelihood Estimation of High-Voltage Pulse Transformer Model Parameters

    CERN Document Server

    Aguglia, D

    2014-01-01

    This paper presents an offline frequency-domain nonlinear and stochastic identification method for equivalent model parameter estimation of high-voltage pulse transformers. Such kinds of transformers are widely used in the pulsed-power domain, and the difficulty in deriving pulsed-power converter optimal control strategies is directly linked to the accuracy of the equivalent circuit parameters. These components require models which take into account electric fields energies represented by stray capacitance in the equivalent circuit. These capacitive elements must be accurately identified, since they greatly influence the general converter performances. A nonlinear frequency-based identification method, based on maximum-likelihood estimation, is presented, and a sensitivity analysis of the best experimental test to be considered is carried out. The procedure takes into account magnetic saturation and skin effects occurring in the windings during the frequency tests. The presented method is validated by experim...

  16. Frequency Correction for MIRO Chirp Transformation Spectroscopy Spectrum

    Science.gov (United States)

    Lee, Seungwon

    2012-01-01

    This software processes the flyby spectra of the Chirp Transform Spectrometer (CTS) of the Microwave Instrument for Rosetta Orbiter (MIRO). The tool corrects the effect of Doppler shift and local-oscillator (LO) frequency shift during the flyby mode of MIRO operations. The frequency correction for CTS flyby spectra is performed and is integrated with multiple spectra into a high signal-to-noise averaged spectrum at the rest-frame RF frequency. This innovation also generates the 8 molecular line spectra by dividing continuous 4,096-channel CTS spectra. The 8 line spectra can then be readily used for scientific investigations. A spectral line that is at its rest frequency in the frame of the Earth or an asteroid will be observed with a time-varying Doppler shift as seen by MIRO. The frequency shift is toward the higher RF frequencies on approach, and toward lower RF frequencies on departure. The magnitude of the shift depends on the flyby velocity. The result of time-varying Doppler shift is that of an observed spectral line will be seen to move from channel to channel in the CTS spectrometer. The direction (higher or lower frequency) in the spectrometer depends on the spectral line frequency under consideration. In order to analyze the flyby spectra, two steps are required. First, individual spectra must be corrected for the Doppler shift so that individual spectra can be superimposed at the same rest frequency for integration purposes. Second, a correction needs to be applied to the CTS spectra to account for the LO frequency shifts that are applied to asteroid mode.

  17. High frequency modeling of power transformers. Stresses and diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Bjerkan, Eilert

    2005-05-15

    In this thesis a reliable, versatile and rigorous method for high frequency power transformer modeling is searched and established. The purpose is to apply this model to sensitivity analysis of FRA (Frequency Response Analysis) which is a quite new diagnostic method for assessing the mechanical integrity of power transformer windings on-site. The method should be versatile in terms of being able to estimate internal and external over voltages and resonances. Another important aspect is that the method chosen is suitable for real transformer geometries. In order to verify the suitability of the model for real transformers, a specific test-object is used. This is a 20MVA transformer, and details are given in chapter 1.4. The high frequency power transformer model is established from geometrical and constructional information from the manufacturer, together with available material characteristics. All circuit parameters in the lumped circuit representation are calculated based on these data. No empirical modifications need to be performed. Comparison shows capability of reasonable accuracy in the range from 10 khz to 1 MHz utilizing a disc-to-disc representation. A compromise between accuracy of model due to discretization and complexity of the model in a turn-to-turn representation is inevitable. The importance of the iron core is emphasized through a comparison of representations with/without the core included. Frequency-dependent phenomena are accurately represented using an isotropic equivalent for windings and core, even with a coarse mesh for the FEM-model. This is achieved through a frequency-dependent complex permeability representation of the materials. This permeability is deduced from an analytical solution of the frequency-dependent magnetic field inside the conductors and the core. The importance of dielectric losses in a transformer model is also assessed. Since published data on the high frequency properties of press board are limited, some initial

  18. Traction Transformer 1 MV.A, Superconducting, Oil-immersed and Medium Frequency

    Directory of Open Access Journals (Sweden)

    Milan Krasl

    2008-01-01

    Full Text Available This paper deals with comparing 3 types of transformers - superconducting, oil-immersed and middle-frequency. These transformers can be used for locomotive as the main transformer. Weight, sizes and losses are introduced. The influence of eddy currents is describes by middle-frequency transformer. The article deals with magnetic properties ofmaterials for higher frequency.

  19. A Frequency Domain Steganography using Z Transform (FDSZT)

    CERN Document Server

    Mandal, J K

    2012-01-01

    Image steganography is art of hiding information onto the cover image. In this proposal a transformed domain based gray scale image authentication/data hiding technique using Z transform (ZT) termed as FDSZT, has been proposed. ZTransform is applied on 2x2 masks of the source image in row major order to transform original sub image (cover image) block to its corresponding frequency domain. One bit of the hidden image is embedded in each mask of the source image onto the fourth LSB of transformed coefficient based on median value of the mask. A delicate handle has also been performed as post embedding operation for proper decoding. Stego sub image is obtained through a reverse transform as final step of embedding in a mask. During the process of embedding, dimension of the hidden image followed by the content of the message/hidden image are embedded. Reverse process is followed during decoding. High PSNR obtained for various images conform the quality of invisible watermark of FDSZT.

  20. Natural frequencies and damping estimation based on continuous wavelet transform

    Institute of Scientific and Technical Information of China (English)

    DAI Yu; SUN He-yi; LI Hui-peng; TANG Wen-yan

    2008-01-01

    The continuous wavelet transform (CWT) based method was improved for estimating the natural fre-quencies and damping ratios of a structural system in this paper. The appropriate scale of CWT was selected by means of the least squares method to identify the systems with closely spaced modes. The important issues relat-ed to estimation accuracy such as mode separation and end effect, were also investigated. These issues were as-sociated with the parameter selection of wavelet function based on the fitting error of least squares. The efficien-cy of the method was confirmed by applying it to a simulated 3dof damped system with two close modes.

  1. Mid-Infrared Frequency Comb Fourier Transform Spectrometer

    CERN Document Server

    Adler, Florian; Foltynowicz, Aleksandra; Cossel, Kevin C; Briles, Travis C; Hartl, Ingmar; Ye, Jun

    2010-01-01

    Optical frequency-comb-based-high-resolution spectrometers offer enormous potential for spectroscopic applications. Although various implementations have been demonstrated, the lack of suitable mid-infrared comb sources has impeded explorations of molecular fingerprinting. Here we present for the first time a frequency-comb Fourier transform spectrometer operating in the 2100-to-3700-cm-1 spectral region that allows fast and simultaneous acquisitions of broadband absorption spectra with up to 0.0056 cm-1 resolution. We demonstrate part-per-billion detection limits in 30 seconds of integration time for various important molecules including methane, ethane, isoprene, and nitrous oxide. Our system enables precise concentration measurements even in gas mixtures that exhibit continuous absorption bands, and it allows detection of molecules at levels below the noise floor via simultaneous analysis of multiple spectral features. This system represents a near real-time, high-resolution, high-bandwidth mid-infrared sp...

  2. High frequency wide-band transformer uses coax to achieve high turn ratio and flat response

    Science.gov (United States)

    De Parry, T.

    1966-01-01

    Center-tap push-pull transformer with toroidal core helically wound with a single coaxial cable creates a high frequency wideband transformer. This transformer has a high-turn ratio, a high coupling coefficient, and a flat broadband response.

  3. Frequency Transformation in the Auditory Lemniscal Thalamocortical System.

    Directory of Open Access Journals (Sweden)

    Kazuo eImaizumi

    2014-07-01

    Full Text Available The auditory lemniscal thalamocortical (TC pathway conveys information from the ventral division of the medial geniculate body to the primary auditory cortex (A1. Although their general topographic organization has been well characterized, functional transformations at the lemniscal TC synapse still remain incompletely codified, largely due to the need for integration of functional anatomical results with the variability observed with various animal models and experimental techniques. In this review, we discuss these issues with classical approaches, such as in vivo extracellular recordings and tracer injections to physiologically identified areas in A1, and then compare these studies with modern approaches, such as in vivo two-photon calcium imaging, in vivo whole-cell recordings, optogenetic methods, and in vitro methods using slice preparations. A surprising finding from a comparison of classical and modern approaches is the similar degree of convergence from thalamic neurons to single A1 neurons and clusters of A1 neurons, although, thalamic convergence to single A1 neurons is more restricted areas within putative thalamic frequency lamina. These comparisons suggest that frequency convergence from thalamic input to A1 is functionally limited. Finally, we consider synaptic organization of TC projections and future directions for research.

  4. Signal line shapes of Fourier transform cavity-enhanced frequency modulation spectroscopy with optical frequency combs

    CERN Document Server

    Johansson, Alexandra C; Khodabakhsh, Amir; Foltynowicz, Aleksandra

    2016-01-01

    We present a thorough analysis of the signal line shapes of Fourier transform-based noise-immune cavity-enhanced optical frequency comb spectroscopy (NICE-OFCS). We discuss the signal dependence on the ratio of the modulation frequency, f${_m}$, to the molecular line width, {\\Gamma}. We compare a full model of the signals and a simplified absorption-like analytical model that has high accuracy for low f${_m}$/{\\Gamma} ratios and is much faster to compute. We verify the theory experimentally by measuring and fitting NICE-OFCS spectra of CO${_2}$ at 1575 nm using a system based on an Er:fiber femtosecond laser and a cavity with a finesse of ~11000.

  5. VIP1: linking Agrobacterium-mediated transformation to plant immunity?

    Science.gov (United States)

    Liu, Yukun; Kong, Xiangpei; Pan, Jiaowen; Li, Dequan

    2010-08-01

    Agrobacterium tumefaciens is the most efficient vehicle used today for the production of transgenic plants and plays an essential role in basic scientific research and in agricultural biotechnology. Previously, plant VirE2-interacting protein 1 (VIP1) was shown to play a role in Agrobacterium-mediated transformation. Recent reports demonstrate that VIP1, as one of the bZIP transcription factors, is also involved in plant immunity responses. Agrobacterium is able to activate and abuse VIP1 for transformation. These findings highlight Agrobacterium-host interaction and unveil how Agrobacterium hijacks host cellular mechanism for its own benefit. This review focuses on the roles played by VIP1 in Agrobacterium-mediated transformation and plant immunity.

  6. Noise reduction combining time-frequency epsilon-filter and M-transform.

    Science.gov (United States)

    Abe, Tomomi; Matsumoto, Mitsuharu; Hashimoto, Shuji

    2008-08-01

    This paper introduces noise reduction combining time-frequency epsilon-filter (TF epsilon-filter) and time-frequency M-transform (TF M-transform). Musical noise is an offensive noise generated due to noise reduction in the time-frequency domain such as spectral subtraction and TF epsilon-filter. It has a deleterious effect on speech recognition. To solve the problem, M-transform is introduced. M-transform is a linear transform based on M-sequence. The method combining the time-domain epsilon-filter (TD epsilon-filter) and time-domain M-transform (TD M-transform) can reduce not only white noise but also impulse noise. Musical noise is isolated in the time-frequency domain, which is similar to impulse noise in the time domain. On these prospects, this paper aims to reduce musical noise by improving M-transform for the time-frequency domain. Noise reduction by using TD M-transform and the TD epsilon-filter is first explained to clarify its features. Then, an improved method applying M-transform to the time-frequency domain, namely TF M-transform, is described. Noise reduction combining the TF epsilon-filter and TF M-transform is also proposed. The proposed method can reduce not only high-level nonstationary noise but also musical noise. Experimental results are also given to demonstrate the performance of the proposed method.

  7. Time-frequency analysis of DC bias vibration of transformer core on the basis of Hilbert–Huang transform

    Directory of Open Access Journals (Sweden)

    Xingmou Liu

    2016-04-01

    Full Text Available This paper presents a time–frequency analysis of the vibration of transformer under direct current (DC bias through Hilbert–Huang transform (HHT. First, the theory of DC bias for the transformer was analyzed. Next, the empirical mode decomposition (EMD process, which is the key in HHT, was introduced. The results of EMD, namely, intrinsic mode functions (IMFs, were calculated and summed by Hilbert transform(HT to obtain time-dependent series in a 2D time–frequency domain. Lastly, a test system of vibration measurement for the transformer was set up. Three direction (x, y, and z axes components of core vibration were measured. Decomposition of EMD and HHT spectra showed that vibration strength increased, and odd harmonics were produced with DC bias. Results indicated that HHT is a viable signal processing tool for transformer health monitoring.

  8. Single-phase vs. Three-phase High Power High Frequency Transformers

    OpenAIRE

    Xue, Jing

    2010-01-01

    This thesis proposes one comparison methodology for single and three-phase high power high frequency transformers in power conversion systems. The objective is to compare the volume of the transformers. And single and three-phase Dual Active Bridge Converter (DAB1 and DAB3) topologies with single and three-phase isolating transformers are selected for the transformer comparison. Design optimization of power transformer has been studied and simplified models have been built for the single and ...

  9. Influence of lasers with non-white frequency noise on the design of coherent optical links

    DEFF Research Database (Denmark)

    Kakkar, Aditya; Navarro, Jaime Rodrigo; Schatz, Richard

    2017-01-01

    We experimentally demonstrate for a 28 Gbaud 64-QAM metro link that the LO frequency noise causes timing impairment. Results show the existence of LO frequency noise spectrum regimes where different design criteria apply....

  10. Calculation of Leakage Inductance for High Frequency Transformers

    DEFF Research Database (Denmark)

    Ouyang, Ziwei; Jun, Zhang; Hurley, William Gerard

    2015-01-01

    Frequency dependent leakage inductance is often observed. High frequency eddy current effects cause a reduction in leakage inductance. The proximity effect between adjacent layers is responsible for the reduction of leakage inductance. This paper gives a detailed analysis of high frequency leakage...... inductance and proposes an accurate prediction methodology. High frequency leakage inductances in several interleaved winding configurations are also discussed. Interleaved winding configurations actually give a smaller degree of reduction of leakage induction at high frequency. Finite Element Analysis (FEA...

  11. A simple structure wavelet transform circuit employing function link neural networks and SI filters

    Science.gov (United States)

    Mu, Li; Yigang, He

    2016-12-01

    Signal processing by means of analog circuits offers advantages from a power consumption viewpoint. Implementing wavelet transform (WT) using analog circuits is of great interest when low-power consumption becomes an important issue. In this article, a novel simple structure WT circuit in analog domain is presented by employing functional link neural network (FLNN) and switched-current (SI) filters. First, the wavelet base is approximated using FLNN algorithms for giving a filter transfer function that is suitable for simple structure WT circuit implementation. Next, the WT circuit is constructed with the wavelet filter bank, whose impulse response is the approximated wavelet and its dilations. The filter design that follows is based on a follow-the-leader feedback (FLF) structure with multiple output bilinear SI integrators and current mirrors as the main building blocks. SI filter is well suited for this application since the dilation constant across different scales of the transform can be precisely implemented and controlled by the clock frequency of the circuit with the same system architecture. Finally, to illustrate the design procedure, a seventh-order FLNN-approximated Gaussian wavelet is implemented as an example. Simulations have successfully verified that the designed simple structure WT circuit has low sensitivity, low-power consumption and litter effect to the imperfections.

  12. Transformational leadership sub-dimensions and their link to leaders' personality and performance

    NARCIS (Netherlands)

    Deinert, A.; Homan, A.C.; Boer, D.; Voelpel, S.C.; Gutermann, D.

    2015-01-01

    The multi-dimensionality of the transformational leadership construct has been under debate in the last decades. To shed more light on this issue, we conducted a meta-analysis (k = 58 studies), examining the transformational leadership sub-dimensions and their links to leader personality and perform

  13. Transformational leadership sub-dimensions and their link to leaders' personality and performance

    NARCIS (Netherlands)

    Deinert, A.; Homan, A.C.; Boer, D.; Voelpel, S.C.; Gutermann, D.

    2015-01-01

    The multi-dimensionality of the transformational leadership construct has been under debate in the last decades. To shed more light on this issue, we conducted a meta-analysis (k = 58 studies), examining the transformational leadership sub-dimensions and their links to leader personality and

  14. Time-frequency analysis of spike-wave discharges using a modified wavelet transform

    NARCIS (Netherlands)

    Bosnyakova, D.Y.; Gabova, A.; Kuznetsova, G.D.; Obukhov, Y.; Midzyanovskaya, I.S.; Salonin, D.V.; Rijn, C.M. van; Coenen, A.M.L.; Tuomisto, L.; Luijtelaar, E.L.J.M. van

    2006-01-01

    The continuous Morlet wavelet transform was used for the analysis of the time-frequency pattern of spike-wave discharges (SWD) as can be recorded in a genetic animal model of absence epilepsy (rats of the WAG/Rij strain). We developed a new wavelet transform that allows to obtain the time-frequency

  15. Gauss linear frequency modulation wavelet transforms and its application to seismic phases identification

    Institute of Scientific and Technical Information of China (English)

    刘希强; 周惠兰; 曹文海; 李红; 李永红; 季爱东

    2002-01-01

    Based on the characteristics of gradual change style seismic signal onset which has more high frequency signal components but less magnitude, this paper selects Gauss linear frequency modulation wavelet as base function to study the change characteristics of Gauss linear frequency modulation wavelet transform with difference wavelet and signal parameters, analyzes the error origin of seismic phases identification on the basis of Gauss linear frequency modulation wavelet transform, puts forward a kind of new method identifying gradual change style seismic phases with background noise which is called fixed scale wavelet transform ratio, and presents application examples about simulation digital signal and actual seismic phases recording onsets identification.

  16. A Novel Soft Switching PWM Power Frequency Converter with Non DC Smoothing Filter Link for Consumer High Frequency Induction Heating

    Science.gov (United States)

    Sugimura, Hisayuki; Muraoka, Hidekazu; Hiraki, Eiji; Hirota, Izuo; Yasui, Kenji; Omori, Hideki; Lee, Hyun-Woo; Nakaoka, Mutsuo

    In this paper, high frequency power converter without DC smoothing electrolytic capacitor filter link which convert the 100V/200Vrms and 60Hz single phase utility frequency AC power into a high frequency AC. This proposed high frequency AC power converter without electrolytic capacitor filter can operate under a principle of soft switching PWM based on a lossless capacitor snubber is proposed and demonstrated for consumer high frequency induction heating (IH). In particular, this high frequency power converter capable of producing a high frequency AC more than 20kHz is developed for consumer IH applications as hot water producer and steamer based on the specially designed spiral type IH-Dual Packs Heater (DPH), which includes the dual mode pulse modulation control scheme based on soft switching PWM for high output power setting and commercial frequency AC zero voltage soft switching pulse density modulation (PDM) for low output power settings. This developed high frequency power frequency converter using trench gate IGBTs is clarified on the basis of experimental and simulation results for its circuit operation of the utility frequency AC to high frequency AC frequency PWM power converter without the electrolytic capacitor bank DC filter link for the IH hot water and IH steamer. These IH appliances are based upon an innovative electromagnetic IH-DPH for fluid heating as heat exchanger in consumer pipeline. Finally, its power regulation characteristics, power conversion efficiency and harmonic current components characteristics including power factor in utility AC grid side are evaluated and discussed from an experimental point of view. The practical effectiveness of this utility frequency AC to high frequency AC soft switching high power frequency converter defined conveniently as high frequency soft switching cyclo-inverter is proved as one of the important products effective for next generation IH application all electricity power utilizations.

  17. A Theory of Transformative Agency in Linked Social-Ecological Systems

    Directory of Open Access Journals (Sweden)

    Frances R. Westley

    2013-09-01

    Full Text Available We reviewed the literature on leadership in linked social-ecological systems and combined it with the literature on institutional entrepreneurship in complex adaptive systems to develop a new theory of transformative agency in linked social-ecological systems. Although there is evidence of the importance of strategic agency in introducing innovation and transforming approaches to management and governance of such systems, there is no coherent theory to explain the wide diversity of strategies identified. Using Holling’s adaptive cycle as a model of phases present in innovation and transformation of resilient social-ecological systems, overlaid by Dorado’s model of opportunity context (opaque, hazy, transparent in complex adaptive systems, we propose a more coherent theory of strategic agency, which links particular strategies, on the part of transformative agents, to phases of system change.

  18. Biomedical Signals Local Maxims Detection Using Time Frequency Transforms

    Directory of Open Access Journals (Sweden)

    Reiz Romulus

    2009-10-01

    Full Text Available The wealth of genomic data currentlyavailable in online databases has caused a need fornew algorithms and analysis techniques to interpretgenomic data. In this paper we explore techniques forlocating critical genomic data in protein sequences andfor estimating the similarity between proteins. Byconverting genomic data into numeric sequencessignal processing methods can be applied to processthe resulting information. We demonstrate the use ofthe Short-Time Fourier Transform and theContinuous Wavelet Transform in locating importantamino acid properties contained in protein sequences.

  19. Development Of Frequency Transfer Via Optical Fiber Link at NICT

    Science.gov (United States)

    2008-12-01

    al., 2006 “Comparison between frequency standards in Europe and the USA at the 10-15 uncertainty level,” Metrologia , 43, 109-120. [4] H. Kiuchi, T...M. Hosokawa, 2008, “Evaluation of caesium atomic fountain NICT-CsF1,” Metrologia , 45, 139-148. [12] M. Kumagai, H. Ito, G. Santarelli, C. Locke, J

  20. Parametric frequency transformation in a superconducting waveguide line with an integrated Josephson oscillator

    Science.gov (United States)

    Denisenko, M. V.; Munyaev, V. O.; Satanin, A. M.

    2016-11-01

    The parametric frequency division in a coplanar waveguide line with an integrated single-contact rf SQUID (Josephson oscillator) is discussed. It is assumed that the oscillator is excited by pump pulses whose carrier frequency can be a multiple of the plasma frequency of the oscillator. It is shown that the Josephson oscillator excited at the pump frequency can induce frequency division by emitting subharmonics that are multiples of the fundamental frequency (fractional resonances). Parameters for which parametric frequency transformation occurs are determined. The possible generalization of this effect to the quantum case in which correlated microwave photons (entangled photon states) can be generated is discussed.

  1. Design-oriented analytic model of phase and frequency modulated optical links

    Science.gov (United States)

    Monsurrò, Pietro; Saitto, Antonio; Tommasino, Pasquale; Trifiletti, Alessandro; Vannucci, Antonello; Cimmino, Rosario F.

    2016-07-01

    An analytic design-oriented model of phase and frequency modulated microwave optical links has been developed. The models are suitable for design of broadband high dynamic range optical links for antenna remoting and optical beamforming, where noise and linearity of the subsystems are a concern Digital filter design techniques have been applied to the design of optical filters working as frequency discriminator, that are the bottleneck in terms of linearity for these systems. The models of frequency modulated, phase modulated, and coherent I/Q link have been used to compare performance of the different architectures in terms of linearity and SFDR.

  2. Design and Measurement of Planar Toroidal Transformers for Very High Frequency Power Applications

    DEFF Research Database (Denmark)

    Knott, Arnold; Pejtersen, Jens

    2012-01-01

    The quest for higher power density has led to research of very high frequency (30-300 MHz) power converters. Magnetic components based on ferrite cores have limited application within this frequency range due to increased core loss. Air-core magnetics is a viable alternative as they do not exhibi...... power converters for very high frequencies. The magnetic coupling factor of both transformers is approx. 60 % and the mutual coupling inductance is dominant up to a frequency of 50 MHz....

  3. Micro-Doppler Frequency Estimation Based on Radon-Wigner Transform

    Directory of Open Access Journals (Sweden)

    Sun Huixia

    2014-01-01

    Full Text Available A nonparametric computationally efficient algorithm is proposed for micro-Doppler frequency estimation, assuming that this non-linear micro-Doppler frequency is approximate linear frequency in short-time intervals. In this algorithm, we use Radon-Wigner transform in short-time intervals to estimate micro-Doppler frequency. Simulation results confirm the effectiveness of the proposed method.Defence Science Journal, Vol. 64, No. 1, January 2014, DOI:10.14429/dsj.64.2980

  4. Quantum Fourier Transforms and the Complexity of Link Invariants for Quantum Doubles of Finite Groups

    OpenAIRE

    Krovi, Hari; Russell, Alexander

    2012-01-01

    Knot and link invariants naturally arise from any braided Hopf algebra. We consider the computational complexity of the invariants arising from an elementary family of finite-dimensional Hopf algebras: quantum doubles of finite groups (denoted D(G), for a group G). Regarding algorithms for these invariants, we develop quantum circuits for the quantum Fourier transform over D(G); in general, we show that when one can uniformly and efficiently carry out the quantum Fourier transform over the ce...

  5. A model for the epigenetic switch linking inflammation to cell transformation: deterministic and stochastic approaches.

    Directory of Open Access Journals (Sweden)

    Claude Gérard

    2014-01-01

    Full Text Available Recently, a molecular pathway linking inflammation to cell transformation has been discovered. This molecular pathway rests on a positive inflammatory feedback loop between NF-κB, Lin28, Let-7 microRNA and IL6, which leads to an epigenetic switch allowing cell transformation. A transient activation of an inflammatory signal, mediated by the oncoprotein Src, activates NF-κB, which elicits the expression of Lin28. Lin28 decreases the expression of Let-7 microRNA, which results in higher level of IL6 than achieved directly by NF-κB. In turn, IL6 can promote NF-κB activation. Finally, IL6 also elicits the synthesis of STAT3, which is a crucial activator for cell transformation. Here, we propose a computational model to account for the dynamical behavior of this positive inflammatory feedback loop. By means of a deterministic model, we show that an irreversible bistable switch between a transformed and a non-transformed state of the cell is at the core of the dynamical behavior of the positive feedback loop linking inflammation to cell transformation. The model indicates that inhibitors (tumor suppressors or activators (oncogenes of this positive feedback loop regulate the occurrence of the epigenetic switch by modulating the threshold of inflammatory signal (Src needed to promote cell transformation. Both stochastic simulations and deterministic simulations of a heterogeneous cell population suggest that random fluctuations (due to molecular noise or cell-to-cell variability are able to trigger cell transformation. Moreover, the model predicts that oncogenes/tumor suppressors respectively decrease/increase the robustness of the non-transformed state of the cell towards random fluctuations. Finally, the model accounts for the potential effect of competing endogenous RNAs, ceRNAs, on the dynamics of the epigenetic switch. Depending on their microRNA targets, the model predicts that ceRNAs could act as oncogenes or tumor suppressors by regulating

  6. A Fault Feature Extraction Method for Rolling Bearing Based on Pulse Adaptive Time-Frequency Transform

    Directory of Open Access Journals (Sweden)

    Jinbao Yao

    2016-01-01

    Full Text Available Shock pulse method is a widely used technique for condition monitoring of rolling bearing. However, it may cause erroneous diagnosis in the presence of strong background noise or other shock sources. Aiming at overcoming the shortcoming, a pulse adaptive time-frequency transform method is proposed to extract the fault features of the damaged rolling bearing. The method arranges the rolling bearing shock pulses extracted by shock pulse method in the order of time and takes the reciprocal of the time interval between the pulse at any moment and the other pulse as all instantaneous frequency components in the moment. And then it visually displays the changing rule of each instantaneous frequency after plane transformation of the instantaneous frequency components, realizes the time-frequency transform of shock pulse sequence through time-frequency domain amplitude relevancy processing, and highlights the fault feature frequencies by effective instantaneous frequency extraction, so as to extract the fault features of the damaged rolling bearing. The results of simulation and application show that the proposed method can suppress the noises well, highlight the fault feature frequencies, and avoid erroneous diagnosis, so it is an effective fault feature extraction method for the rolling bearing with high time-frequency resolution.

  7. Fourier transform spectroscopy around 3 microns with a broad difference frequency comb

    CERN Document Server

    Meek, Samuel A; Guelachvili, Guy; Hänsch, Theodor W; Picqué, Nathalie

    2013-01-01

    We characterize a new mid-infrared frequency comb generator based on difference frequency generation around 3.2 microns. High power per comb mode (>10-7 W/mode) is obtained over a broad spectral span (>700 nm). The source is used for direct absorption spectroscopy with a Michelson-based Fourier transform interferometer.

  8. Quantum Image Encryption Based on Iterative Framework of Frequency-Spatial Domain Transforms

    Science.gov (United States)

    Wang, Han; Wang, Jian; Geng, Ya-Cong; Song, Yan; Liu, Ji-Qiang

    2017-10-01

    A novel quantum image encryption and decryption algorithm based on iteration framework of frequency-spatial domain transforms is proposed. In this paper, the images are represented in the flexible representation for quantum images (FRQI). Previous quantum image encryption algorithms are realized by spatial domain transform to scramble the position information of original images and frequency domain transform to encode the color information of images. But there are some problems such as the periodicity of spatial domain transform, which will make it easy to recover the original images. Hence, we present the iterative framework of frequency-spatial domain transforms. Based on the iterative framework, the novel encryption algorithm uses Fibonacci transform and geometric transform for many times to scramble the position information of the original images and double random-phase encoding to encode the color information of the images. The encryption keys include the iterative time t of the Fibonacci transform, the iterative time l of the geometric transform, the geometric transform matrix G i which is n × n matrix, the classical binary sequences K (k0k1{\\ldots } k_{2^{2n}-1}) and D(d0d1{\\ldots } d_{2^{2n}-1}). Here the key space of Fibonacci transform and geometric transform are both estimated to be 226. The key space of binary sequences is (2 n× n ) × (2 n× n ). Then the key space of the entire algorithm is about 2^{2{n2}+52}. Since all quantum operations are invertible, the quantum image decryption algorithm is the inverse of the encryption algorithm. The results of numerical simulation and analysis indicate that the proposed algorithm has high security and high sensitivity.

  9. Compact high voltage, high peak power, high frequency transformer for converter type modulator applications.

    Science.gov (United States)

    Reghu, T; Mandloi, V; Shrivastava, Purushottam

    2016-04-01

    The design and development of a compact high voltage, high peak power, high frequency transformer for a converter type modulator of klystron amplifiers is presented. The transformer has been designed to operate at a frequency of 20 kHz and at a flux swing of ±0.6 T. Iron (Fe) based nanocrystalline material has been selected as a core for the construction of the transformer. The transformer employs a specially designed solid Teflon bobbin having 120 kV insulation for winding the high voltage secondary windings. The flux swing of the core has been experimentally found by plotting the hysteresis loop at actual operating conditions. Based on the design, a prototype transformer has been built which is per se a unique combination of high voltage, high frequency, and peak power specifications. The transformer was able to provide 58 kV (pk-pk) at the secondary with a peak power handling capability of 700 kVA. The transformation ratio was 1:17. The performance of the transformer is also presented and discussed.

  10. Precise and fast spatial-frequency analysis using the iterative local Fourier transform.

    Science.gov (United States)

    Lee, Sukmock; Choi, Heejoo; Kim, Dae Wook

    2016-09-19

    The use of the discrete Fourier transform has decreased since the introduction of the fast Fourier transform (fFT), which is a numerically efficient computing process. This paper presents the iterative local Fourier transform (ilFT), a set of new processing algorithms that iteratively apply the discrete Fourier transform within a local and optimal frequency domain. The new technique achieves 210 times higher frequency resolution than the fFT within a comparable computation time. The method's superb computing efficiency, high resolution, spectrum zoom-in capability, and overall performance are evaluated and compared to other advanced high-resolution Fourier transform techniques, such as the fFT combined with several fitting methods. The effectiveness of the ilFT is demonstrated through the data analysis of a set of Talbot self-images (1280 × 1024 pixels) obtained with an experimental setup using grating in a diverging beam produced by a coherent point source.

  11. A non-linear frequency transform and its application to speaker recognition

    Institute of Scientific and Technical Information of China (English)

    YU Yibiao; YUAN Dongmei; XUE Feng

    2009-01-01

    Based on analyzing contribution of short-time spectrum in different frequency sub-bands to speaker recognition and using of polynomial curve matching techniques, a non-linear frequency transform and feature detection algorithm are proposed to highlight the speaker's individuality in short-time spectrum of speech. The experimental results show that the perfor-mance of speaker recognition system is improved effectively, the average error rate of recognition relatively falls about 70.5%, 60.8% and 70.5% in comparison with classical frequency transform of Mel, Bark and ERB (Equivalent Rectangular Bandwidth) respectively.

  12. Transformation properties of dynamic χ(2) holograms generating at the difference frequency

    Science.gov (United States)

    Miloglyadov, E. V.; Stasel'ko, D. I.

    2016-07-01

    The transformation properties of dynamic χ(2) holograms generating at the difference frequency are analyzed as applied to the position and scales of reconstructed images. Some regularities are established for the spatial localization and scales of images for different combinations of frequencies and positions of the reference and object point sources, involved in the formation of a holographic image. The formation of amplitude transparency images, reconstructed by dynamic χ(2) holograms with a decrease or conservation of the object beam frequency, and their transformations are experimentally demonstrated.

  13. The Study of Several Variants of the Traction Drive with Middle-Frequency Transformer

    Directory of Open Access Journals (Sweden)

    Martin Pittermann

    2008-01-01

    Full Text Available This paper presents research motivated by industrial demand for special traction drive topology devoted to minimization of traction transformer weight of traction vehicles. The main attention has been given to the special traction drive topology for AC power systems: input high voltage trolley converter (single phase – middle frequency transformer (single phase – output converter (single phase voltage-source active rectifier + three phase voltage-source inverter - traction motor. This configuration can minimize traction transformer weight against topology with classical 50Hz traction transformer. Several variants of innovative topologies of the traction vehicles fulfil the weight reduce requirements have beenpresented.

  14. A frequency measurement algorithm for non-stationary signals by using wavelet transform

    Science.gov (United States)

    Seo, Seong-Heon; Oh, Dong Keun

    2016-11-01

    Scalogram is widely used to measure instantaneous frequencies of non-stationary signals. However, the basic property of the scalogram is observed only for stationary sinusoidal functions. A property of the scalogram for non-stationary signal is analytically derived in this paper. Based on the property, a new frequency measurement algorithm is proposed. In addition, a filter that can separate two similar frequency signals is developed based on the wavelet transform.

  15. Analysis of Energy Overshoot of High Frequency Waves with Wavelet Transform

    Institute of Scientific and Technical Information of China (English)

    WEN Fan

    2000-01-01

    A study is made on the overshoot phenomena in wind-generated waves. The surface displace ments of time-growing waves are measured at four fetches in a wind wave channel. The evolution of high frequency waves is displayed with wavelet transform. The results are compared with Sutherland's. It is found that high frequency wave components experience much stronger energy overshoot in the evolution.The energy of high frequency waves decreases greatly after overshoot

  16. Inversion of Fourier Transforms by Means of Scale-Frequency Series

    Directory of Open Access Journals (Sweden)

    Nassar H. S. Haidar

    2014-01-01

    Full Text Available We report on inversion of the Fourier transform when the frequency variable can be scaled in a variety of different ways that improve the resolution of certain parts of the frequency domain. The corresponding inverse Fourier transform is shown to exist in the form of two dual scale-frequency series. Upon discretization of the continuous scale factor, this Fourier transform series inverse becomes a certain nonharmonic double series, a discretized scale-frequency (DSF series. The DSF series is also demonstrated, theoretically and practically, to be rate-optimizable with respect to its two free parameters, when it satisfies, as an entropy maximizer, a pertaining recursive nonlinear programming problem incorporating the entropy-based uncertainty principle.

  17. Cascaded multiplexed optical link on a telecommunication network for frequency dissemination.

    Science.gov (United States)

    Lopez, Olivier; Haboucha, Adil; Kéfélian, Fabien; Jiang, Haifeng; Chanteau, Bruno; Roncin, Vincent; Chardonnet, Christian; Amy-Klein, Anne; Santarelli, Giorgio

    2010-08-01

    We demonstrate a cascaded optical link for ultrastable frequency dissemination comprised of two compensated links of 150 km and a repeater station. Each link includes 114 km of Internet fiber simultaneously carrying data traffic through a dense wavelength division multiplexing technology, and passes through two routing centers of the telecommunication network. The optical reference signal is inserted in and extracted from the communication network using bidirectional optical add-drop multiplexers. The repeater station operates autonomously ensuring noise compensation on the two links and the ultra-stable signal optical regeneration. The compensated link shows a fractional frequency instability of 3 x 10(-15) at one second measurement time and 5 x 10(-20) at 20 hours. This work paves the way to a wide dissemination of ultra-stable optical clock signals between distant laboratories via the Internet network.

  18. Cascaded multiplexed optical link on a telecommunication network for frequency dissemination

    CERN Document Server

    Lopez, Olivier; Kéfélian, Fabien; Jiang, Haifeng; Chanteau, Bruno; Roncin, Vincent; Chardonnet, Christian; Amy-Klein, Anne; Santarelli, Georgio

    2010-01-01

    We demonstrate a cascaded optical link for ultrastable frequency dissemination comprised of two compensated links of 150 km and a repeater station. Each link includes 114 km of Internet fiber simultaneously carrying data traffic through a dense wavelength division multiplexing technology, and passes through two routing centers of the telecommunication network. The optical reference signal is inserted in and extracted from the communication network using bidirectional optical add-drop multiplexers. The repeater station operates autonomously ensuring noise compensation on the two links and the ultra-stable signal optical regeneration. The compensated link shows a fractional frequency instability of 3 \\times 10-15 at one second measurement time and 5 \\times 10-20 at 20 hours. This work paves the way to a wide dissemination of ultra-stable optical clock signals between distant laboratories via the Internet network.

  19. Embodied mental rotation: A special link between egocentric transformation and the bodily self

    Directory of Open Access Journals (Sweden)

    Sandra eKaltner

    2014-06-01

    Full Text Available This experiment investigated the influence of motor expertise on object-based versus egocentric transformations in a chronometric mental rotation task using images of either the own or another person’s body as stimulus material. According to the embodied cognition viewpoint, we hypothesized motor-experts to outperform non-motor experts specifically in the egocentric condition because of higher kinesthetic representation and motor simulations compared to object-based transformations. In line with this, we expected that images of the own body are solved faster than another person’s body stimuli. Results showed a benefit of motor expertise and representations of another person’s body, but only for the object-based transformation task. That is, this other-advantage diminishes in egocentric transformations. Since motor experts didn’t show any specific expertise in rotational movements, we concluded that using human bodies as stimulus material elicits embodied spatial transformations, which facilitates performance exclusively for egocentric transformations. Regarding stimulus material, the other-advantage ascribed to increased self-awareness-consciousness distracting attention-demanding resources, disappeared in the egocentric condition. This result may be due to the stronger link between the bodily self and motor representations compared to that emerging in object-based transformations.

  20. Hydrocarbon Reservoir Prediction Using Bi-Gaussian S Transform Based Time-Frequency Analysis Approach

    Science.gov (United States)

    Cheng, Z.; Chen, Y.; Liu, Y.; Liu, W.; Zhang, G.

    2015-12-01

    Among those hydrocarbon reservoir detection techniques, the time-frequency analysis based approach is one of the most widely used approaches because of its straightforward indication of low-frequency anomalies from the time-frequency maps, that is to say, the low-frequency bright spots usually indicate the potential hydrocarbon reservoirs. The time-frequency analysis based approach is easy to implement, and more importantly, is usually of high fidelity in reservoir prediction, compared with the state-of-the-art approaches, and thus is of great interest to petroleum geologists, geophysicists, and reservoir engineers. The S transform has been frequently used in obtaining the time-frequency maps because of its better performance in controlling the compromise between the time and frequency resolutions than the alternatives, such as the short-time Fourier transform, Gabor transform, and continuous wavelet transform. The window function used in the majority of previous S transform applications is the symmetric Gaussian window. However, one problem with the symmetric Gaussian window is the degradation of time resolution in the time-frequency map due to the long front taper. In our study, a bi-Gaussian S transform that substitutes the symmetric Gaussian window with an asymmetry bi-Gaussian window is proposed to analyze the multi-channel seismic data in order to predict hydrocarbon reservoirs. The bi-Gaussian window introduces asymmetry in the resultant time-frequency spectrum, with time resolution better in the front direction, as compared with the back direction. It is the first time that the bi-Gaussian S transform is used for analyzing multi-channel post-stack seismic data in order to predict hydrocarbon reservoirs since its invention in 2003. The superiority of the bi-Gaussian S transform over traditional S transform is tested on a real land seismic data example. The performance shows that the enhanced temporal resolution can help us depict more clearly the edge of the

  1. Fast Frequency Estimation by Zero Crossings of Differential Spline Wavelet Transform

    Directory of Open Access Journals (Sweden)

    Kenneth R. Castleman

    2005-05-01

    Full Text Available Zero crossings or extrema of a wavelet transform constitute important signatures for signal analysis with the advantage of great simplicity. In this paper, we introduce a fast frequency-estimation method based on zero-crossing counting in the transform domain of a family of differential spline wavelets. The resolution and order of the vanishing moments of the chosen wavelets have a close relation with the frequency components of a signal. Theoretical results on estimating the highest and the lowest frequency components are derived, which are particularly useful for frequency estimation of harmonic signals. The results are illustrated with the help of several numerical examples. Finally, we discuss the connection of this approach with other frequency estimation methods, with the high-order level-crossing analysis in statistics, and with the scaling theorem in computer vision.

  2. Pitch link loads reduction of variable speed rotors by variable tuning frequency fluidlastic isolators

    Institute of Scientific and Technical Information of China (English)

    Han Dong

    2015-01-01

    To reduce the pitch link loads of variable speed rotors, variable tuning frequency fluid-lastic isolators are proposed. This isolator utilizes the variation of centrifugal force due to the change of rotor speed to change the tuning port area ratio, which can change the tuning frequency of the isolator. A rotor model including the model of fluidlastic isolator is coupled with a fuselage model to predict the steady responses of the rotor system in forward flight. The aeroelastic analyses indicate that distinct performance improvement in pitch link load control can be achieved by the utilization of variable frequency isolators compared with the constant tuning frequency isolators. The 4/rev (per revolution) pitch link load is observed to be reduced by 87.6%compared with the increase of 56.3%by the constant frequency isolator, when the rotor speed is reduced by 16.7%. The isolation ability at different rotor speeds in different flight states is investigated. To achieve overall load reduction within the whole range of rotor speed, the strategy of the variation of tuning frequency is adjusted. The results indicate that the 4/rev pitch link load within the whole rotor speed range is decreased.

  3. Pitch link loads reduction of variable speed rotors by variable tuning frequency fluidlastic isolators

    Directory of Open Access Journals (Sweden)

    Han Dong

    2015-10-01

    Full Text Available To reduce the pitch link loads of variable speed rotors, variable tuning frequency fluidlastic isolators are proposed. This isolator utilizes the variation of centrifugal force due to the change of rotor speed to change the tuning port area ratio, which can change the tuning frequency of the isolator. A rotor model including the model of fluidlastic isolator is coupled with a fuselage model to predict the steady responses of the rotor system in forward flight. The aeroelastic analyses indicate that distinct performance improvement in pitch link load control can be achieved by the utilization of variable frequency isolators compared with the constant tuning frequency isolators. The 4/rev (per revolution pitch link load is observed to be reduced by 87.6% compared with the increase of 56.3% by the constant frequency isolator, when the rotor speed is reduced by 16.7%. The isolation ability at different rotor speeds in different flight states is investigated. To achieve overall load reduction within the whole range of rotor speed, the strategy of the variation of tuning frequency is adjusted. The results indicate that the 4/rev pitch link load within the whole rotor speed range is decreased.

  4. Equivalent circuit of radio frequency-plasma with the transformer model.

    Science.gov (United States)

    Nishida, K; Mochizuki, S; Ohta, M; Yasumoto, M; Lettry, J; Mattei, S; Hatayama, A

    2014-02-01

    LINAC4 H(-) source is radio frequency (RF) driven type source. In the RF system, it is required to match the load impedance, which includes H(-) source, to that of final amplifier. We model RF plasma inside the H(-) source as circuit elements using transformer model so that characteristics of the load impedance become calculable. It has been shown that the modeling based on the transformer model works well to predict the resistance and inductance of the plasma.

  5. Simultaneous transfer of optical frequency and time over 306 km long-haul optical fibre link

    Science.gov (United States)

    Hucl, Vaclav; Cizek, Martin; Pravdova, Lenka; Rerucha, Simon; Hrabina, Jan; Mikel, Bretislav; Smotlacha, Vladimir; Vojtech, Josef; Lazar, Josef; Cip, Ondrej

    2016-12-01

    Optical fibre links for distributing optical frequencies and time stamps were researched and experimentally tested in the past fifteen years. They have been used mainly for stability comparison of experimental optical clocks. But recent development puts demands on a technology transfer from laboratory experiments to the real industry. The remote calibration of interrogators of Fibre Bragg Grating strain sensory networks is one of important examples. The first step of the adoption the time and frequency broadcasting should be the drop-out free long-term operation of this technology between research laboratories connected via long-haul fibre links. We present a 306 km long-haul optical fibre link between the cities of Prague and Brno in the Czech Republic where a coherent transfer of stable optical frequency and a stable time signal has been firstly demonstrated. The link between ISI CAS Brno and CESNET Prague uses an internet communication fibre where a window of 1540-1546 nm is dedicated for the coherent transfer and 1PPS signal. The link is equipped with 6 bidirectional EDFA amplifiers. The optical frequency standard based on the highly-coherent laser Koheras Adjustik working at 1540.5 nm and stabilized with a saturation absorption spectroscopy technique was used for the coherent wave transfer. The suppression of the Doppler shift induced by the optical fibre was based on an accoustooptical modulator with a servo-loop including a fast PID controller processing the beat-note frequency given by mixing of the Adjustik laser (Brno) and the reflected frequency of this laser from the far end of 306 km long-haul fibre link (Prague). We verified the Doppler shift suppression for the coherent wave with a measuring method analysing the transport delay of the 1PPS signal.

  6. Analysis and application of wavelet transform in target imaging and detection of stepped frequency MMW radar

    Institute of Scientific and Technical Information of China (English)

    Zhao Bin; Quan Taifan; Wang Jinrong

    2005-01-01

    The imaging and target detection methods for stepped frequency signal based on the wavelet transform and its power spectrum are investigated. Not only an imaging and target detection algorithm for stepped frequency signal based on the wavelet transform, but also its respective power spectrum are proposed. The multisampling property of stepped frequency signal is studied and wavelet transform is well suited for analyzing the signal. After multisampling property of stepped frequency signal being studied, it is shown that the wavelet transform is appropriate to analyze the signal. Based on the theory, the wavelet power spectrum analysis is applied to obtain the target range profile and the binary wavelet transform is used to perform target detection. To determine a suitable wavelet scaling for imaging of range profile' s MMW radar, the distance resolution △R technique is proposed. The effectiveness of this new method is evaluated using simulated noisy radar signal. Results show that the proposed method can bring out the exactness and low computational complexity of this method.

  7. First international comparison of fountain primary frequency standards via a long distance optical fiber link

    Science.gov (United States)

    Guéna, J.; Weyers, S.; Abgrall, M.; Grebing, C.; Gerginov, V.; Rosenbusch, P.; Bize, S.; Lipphardt, B.; Denker, H.; Quintin, N.; Raupach, S. M. F.; Nicolodi, D.; Stefani, F.; Chiodo, N.; Koke, S.; Kuhl, A.; Wiotte, F.; Meynadier, F.; Camisard, E.; Chardonnet, C.; Le Coq, Y.; Lours, M.; Santarelli, G.; Amy-Klein, A.; Le Targat, R.; Lopez, O.; Pottie, P. E.; Grosche, G.

    2017-06-01

    We report on the first comparison of distant caesium fountain primary frequency standards (PFSs) via an optical fiber link. The 1415 km long optical link connects two PFSs at LNE-SYRTE (Laboratoire National de métrologie et d’Essais—SYstème de Références Temps-Espace) in Paris (France) with two at PTB (Physikalisch-Technische Bundesanstalt) in Braunschweig (Germany). For a long time, these PFSs have been major contributors to accuracy of the International Atomic Time (TAI), with stated accuracies of around 3× {{10}-16} . They have also been the references for a number of absolute measurements of clock transition frequencies in various optical frequency standards in view of a future redefinition of the second. The phase coherent optical frequency transfer via a stabilized telecom fiber link enables far better resolution than any other means of frequency transfer based on satellite links. The agreement for each pair of distant fountains compared is well within the combined uncertainty of a few 10-16 for all the comparisons, which fully supports the stated PFSs’ uncertainties. The comparison also includes a rubidium fountain frequency standard participating in the steering of TAI and enables a new absolute determination of the 87Rb ground state hyperfine transition frequency with an uncertainty of 3.1× {{10}-16} . This paper is dedicated to the memory of André Clairon, who passed away on 24 December 2015, for his pioneering and long-lasting efforts in atomic fountains. He also pioneered optical links from as early as 1997.

  8. Evaluation at the Remote Site for Ultra-stable Radio Frequency Dissemination via Fiber Links

    CERN Document Server

    Li, Shanglin; Zhang, Shuangyou; Li, Dawei; Leng, Jianxiao; Zhao, Jianye

    2016-01-01

    We demonstrate a method which can directly evaluate the radio frequency transfer quality via fiber links at the remote site. Coherent signals are first transferred to the same remote site via two stabilized fiber links. The two signals at the remote site are compared with each other. The relative phase difference can represent transfer stability loss. This evaluation method at the remote site has been compared with the traditional one with which the signal is evaluated at the local site. The two results match perfectly. It indicates that the method is available to evaluate the transfer performance of radio frequency (RF) dissemination in such applications as antenna array systems.

  9. Investigation of Frequency-Domain Link Adaptation for a 5-MHz OFDMA/HSDPA system

    DEFF Research Database (Denmark)

    Pokhariyal, Akhilesh; Kolding, Troels E.; Frederiksen, Frank

    2005-01-01

    In this paper, we investigate frequency domain link adaptation (FDLA), e.g. utilizing the frequency selectivity of the channel in an OFDMA system. To make the study specific and based on realistic parameters, we re-use the specifications from a recent 3GPP 5-MHz OFDMA study item. The link...... find that optimum waterfilling power distribution only provides a marginal gain over a simpler on/off equal power distribution algorithm per sub-carrier pool when signaling imperfections are taken into account....

  10. The Simulation of the Traction Drive with Middle-Frequency Transformer

    Directory of Open Access Journals (Sweden)

    Miroslav Los

    2008-01-01

    Full Text Available This paper presents research motivated by industrial demand for special traction drive topology devoted to minimization of traction transformer weight against topology with classical 50Hz traction transformer. The special traction drive topology for AC power systems consists of input high voltage trolley converter (single phase matrix converter –middle frequency transformer - output converter - traction motor has been described. The main attention has been given tothe control algorithm of the traction topology (inserting of NULL vector of matrix converter and Two-value control ofsecondary active rectifier.

  11. A Review of Frequency Response Analysis Methods for Power Transformer Diagnostics

    Directory of Open Access Journals (Sweden)

    Saleh Alsuhaibani

    2016-10-01

    Full Text Available Power transformers play a critical role in electric power networks. Such transformers can suffer failures due to multiple stresses and aging. Thus, assessment of condition and diagnostic techniques are of great importance for improving power network reliability and service continuity. Several techniques are available to diagnose the faults within the power transformer. Frequency response analysis (FRA method is a powerful technique for diagnosing transformer winding deformation and several other types of problems that are caused during manufacture, transportation, installation and/or service life. This paper provides a comprehensive review on FRA methods and their applications in diagnostics and fault identification for power transformers. The paper discusses theory and applications of FRA methods as well as various issues and challenges faced in the application of this method.

  12. Long-Distance Frequency Transfer Over an Urban Fiber Link Using Optical Phase Stabilization

    Science.gov (United States)

    2008-12-01

    measurement frequency andwidth is 10 Hz. ig. 6. (Color online) Scheme of the 172 km link ( EDFA , see ext; AOM, PD, see Fig. 2).nd an acousto-optic...amplifier (EDFA2) was added t the remote end to amplify the return signal. Tempera- ure variations in EDFAs induce phase fluctuations, hich degrade...the long-term frequency stability. In order o correctly compensate for this effect, the output optical ignal should pass once through the EDFAs , whereas

  13. Improvement of Accuracy in Damage Localization Using Frequency Slice Wavelet Transform

    Directory of Open Access Journals (Sweden)

    Xinglong Liu

    2012-01-01

    Full Text Available Damage localization is a primary objective of damage identification. This paper presents damage localization in beam structure using impact-induced Lamb wave and Frequency Slice Wavelet Transform (FSWT. FSWT is a new time-frequency analysis method and has the adaptive resolution feature. The time-frequency resolution is a vital factor affecting the accuracy of damage localization. In FSWT there is a unique parameter controlling the time-frequency resolution. To improve the accuracy of damage localization, a generalized criterion is proposed to determine the parameter value for achieving a suitable time-frequency resolution. For damage localization, the group velocity dispersion curve (GVDC of A0 Lamb waves in beam is first accurately estimated using FSWT, and then the arrival times of reflection wave from the crack for some individual frequency components are determined. An average operation on the calculated propagation distance is then performed to further improve the accuracy of damage localization.

  14. Parameter estimation of linear and quadratic chirps by employing the fractional fourier transform and a generalized time frequency transform

    Indian Academy of Sciences (India)

    Shishir B Sahay; T Meghasyam; Rahul K Roy; Gaurav Pooniwala; Sasank Chilamkurthy; Vikram Gadre

    2015-06-01

    This paper is targeted towards a general readership in signal processing. It intends to provide a brief tutorial exposure to the Fractional Fourier Transform, followed by a report on experiments performed by the authors on a Generalized Time Frequency Transform (GTFT) proposed by them in an earlier paper. The paper also discusses the extension of the uncertainty principle to the GTFT. This paper discusses some analytical results of the GTFT. We identify the eigenfunctions and eigenvalues of the GTFT. The time shift property of the GTFT is discussed. The paper describes methods for estimation of parameters of individual chirp signals on receipt of a noisy mixture of chirps. A priori knowledge of the nature of chirp signals in the mixture – linear or quadratic is required, as the two proposed methods fall in the category of model-dependent methods for chirp parameter estimation.

  15. Extracting Micro-Doppler Radar Signatures from Rotating Targets Using Fourier-Bessel Transform and Time-Frequency Analysis

    Science.gov (United States)

    2014-10-16

    1 Extracting micro-Doppler radar signatures from rotating targets using Fourier- Bessel Transform and Time-Frequency analysis P. Suresh1,T...kvenkataramanaiah@sssihl.edu.in Abstract In this paper, we report the efficiency of Fourier Bessel transform and time-frequency based method in conjunction with...decomposed into stationary and non-stationary components using Fourier Bessel transform in conjunction with the fractional Fourier transform. The

  16. Frequency division multiplexed microwave and baseband digital optical fiber link for phased array antennas

    Science.gov (United States)

    Heim, Peter J.; McClay, C. Phillip

    1990-05-01

    A frequency-division multiplexed optical fiber link is described in which microwave (1-8 GHz) and baseband digital (1-10 Mb/s) signals are combined electrically and transmitted through a direct-modulation microwave optical link. The microwave signal does not affect bit error rate (BER) performance of the Manchester-coded baseband digital data link. The baseband digital signal affects microwave signal quality by generating second-order intermodulation noise. The intermodulation noise power density is found to be proportional to both the microwave input power and the digital input power, enabling the system to be modeled as a mixer (AM modulator). The conversion loss for the digital signal is approximately 68 dB for a 1-GHz microwave signal and is highly dependent on the microwave frequency, reaching a minimum value of 41 dB at 4.5 GHz, corresponding to the laser diode relaxation oscillation frequency. It is shown that Manchester coding on the digital link places the intermodulation noise peak away from the microwave signal, preventing degradation of close-carrier phase noise (<1 kHz offset). A direct trade-off between intermodulation noise and digital link margin is developed to project system performance.

  17. Frequency domain volume rendering by the wavelet X-ray transform

    NARCIS (Netherlands)

    Westenberg, Michel A.; Roerdink, Jos B.T.M.

    2000-01-01

    We describe a wavelet-based X-ray rendering method in the frequency domain with a smaller time complexity than wavelet splatting. Standard Fourier volume rendering is summarized and interpolation and accuracy issues are briefly discussed. We review the implementation of the fast wavelet transform in

  18. [Promotion of transformation frequency of soybean (Glycine max L.) protoplasts using poly-L-ornithine].

    Science.gov (United States)

    Nan, X R; Wei, Z M

    1999-12-01

    The foreign Bt gene was transferred into protoplasts of soybean using PEG and PLO methods, respectively. The result indicated that the transformation frequency of PLO method was about 0.1% higher than PEG method. The PCR and Southern blotting analysis of the regeneration plants confirmed the integration of foreign gene into the genome of soybean.

  19. Focusing transform-based direction-of-arrival method exploiting multi-cycle frequencies

    Institute of Scientific and Technical Information of China (English)

    HUANG Zhitao; JIANG Wenli; ZHOU Yiyu

    2005-01-01

    When single cycle frequency is employed, the existing spectral correlation-signal subspace fitting (SC-SSF) algorithms usually contain two disadvantages: those single-cycle estimators cannot reach the best performance; it is inconvenient to be applied in practice since the right cycle frequency has to be selected. Based on the Jacobi-Anger expansion and the idea of focusing transform, a new approach exploiting multi-cycle frequencies of cyclostationary signal is discussed in this paper. Simulation results demonstrate the effectiveness of the new method.

  20. Fractional Fourier transform for partially coherent beam in spatial-frequency domain

    Institute of Scientific and Technical Information of China (English)

    Cai Yang-Jian; Lin Qiang

    2004-01-01

    By using Fourier transform and the tensor analysis method, the fractional Fourier transform (FRT) in the spatialfrequency domain for partially coherent beams is derived. Based on the FRT in the spatial-frequency domain, an analytical transform formula is derived for a partially coherent twisted anisotropic Gaussian-Schell model (GSM) beam passing through the FRT system. The connections between the FRT formula and the generalized diffraction integral formulae for partially coherent beams through an aligned optical system and a misaligned optical system in the spatialfrequency domain are discussed, separately. By using the derived formula, the intensity distribution of partially coherent twisted anisotropic GSM beams in the FRT plane are studied in detail. The formula derived provide a convenient tool for analysing and calculating the FRTs of the partially coherent beams in spatial-frequency domain.

  1. COMPARATIVE ANALYSIS OF APPLICATION EFFICIENCY OF ORTHOGONAL TRANSFORMATIONS IN FREQUENCY ALGORITHMS FOR DIGITAL IMAGE WATERMARKING

    Directory of Open Access Journals (Sweden)

    Vladimir A. Batura

    2014-11-01

    Full Text Available The efficiency of orthogonal transformations application in the frequency algorithms of the digital watermarking of still images is examined. Discrete Hadamard transform, discrete cosine transform and discrete Haar transform are selected. Their effectiveness is determined by the invisibility of embedded in digital image watermark and its resistance to the most common image processing operations: JPEG-compression, noising, changing of the brightness and image size, histogram equalization. The algorithm for digital watermarking and its embedding parameters remain unchanged at these orthogonal transformations. Imperceptibility of embedding is defined by the peak signal to noise ratio, watermark stability– by Pearson's correlation coefficient. Embedding is considered to be invisible, if the value of the peak signal to noise ratio is not less than 43 dB. Embedded watermark is considered to be resistant to a specific attack, if the Pearson’s correlation coefficient is not less than 0.5. Elham algorithm based on the image entropy is chosen for computing experiment. Computing experiment is carried out according to the following algorithm: embedding of a digital watermark in low-frequency area of the image (container by Elham algorithm, exposure to a harmful influence on the protected image (cover image, extraction of a digital watermark. These actions are followed by quality assessment of cover image and watermark on the basis of which efficiency of orthogonal transformation is defined. As a result of computing experiment it was determined that the choice of the specified orthogonal transformations at identical algorithm and parameters of embedding doesn't influence the degree of imperceptibility for a watermark. Efficiency of discrete Hadamard transform and discrete cosine transformation in relation to the attacks chosen for experiment was established based on the correlation indicators. Application of discrete Hadamard transform increases

  2. The frequency and malignant transformation rate of oral lichen planus and leukoplakia--a retrospective study.

    Science.gov (United States)

    Brzak, Bozana Loncar; Mravak-Stipetić, Marinka; Canjuga, Ivana; Baricević, Marinka; Balicević, Drinko; Sikora, Miroslav; Filipović-Zore, Irina

    2012-09-01

    The aim of this retrospective study was to determine the frequency and malignant transformation rate of oral lichen planus and leukoplakia in a large group of oral medicine patients. Study included 12 508 patients who were referred between 1998 and 2007 to the Department of Oral Medicine. The frequency of OLP was 4.30%, leukoplakia 1.11%, and combined diagnoses 0.14%. In primary biopsies dysplasia was found in 12.96% of patients with leukoplakia and not in one with OLP and combined lesions. The highest frequency of leukoplakia was found in smokers. Women were found as predominant sufferers of both diseases and their combination. During the observed period often years malignant transformation of OLP was not detected, unlike leukoplakia where it was 0.64%. The frequency of OLP and leukoplakia in our study are comparable to other similar studies. The highest frequency of malignant transformation was observed in those patients who did not respond to our invitation to regular check-up. It is therefore neccessary to perform a detailed examination of the oral cavity in these patients and to raise patients awareness of the disease and the importance of regular follow-up.

  3. Fourier Self-deconvolution Using Approximation Obtained from Frequency Domain Wavelet Transform as a Linear Function

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A new method of resolving overlapped peak, Fourier self-deconvolution (FSD) using approximation CN obtained from frequency domain wavelet transform of F(ω) yielded by Fourier transform of overlapped peak signals f(t) as the linear function, was presented in this paper.Compared with classical FSD, the new method exhibits excellent resolution for different overlapped peak signals such as HPLC signals, and have some characteristics such as an extensive applicability for any overlapped peak shape signals and a simple operation because of no selection procedure of the linear function. Its excellent resolution for those different overlapped peak signals is mainly because F(ω) obtained from Fourier transform of f(t) and CN obtained from wavelet transform of F(ω) have the similar linearity and peak width. The effect of those fake peaks can be eliminated by the algorithm proposed by authors. This method has good potential in the process of different overlapped peak signals.

  4. Phase-coherent frequency comparison of optical clocks using a telecommunication fiber link.

    Science.gov (United States)

    Schnatz, Harald; Terra, Osama; Predehl, Katharina; Feldmann, Thorsten; Legero, Thomas; Lipphardt, Burghard; Sterr, Uwe; Grosche, Gesine; Holzwarth, Ronald; Hänsch, Theodor W; Udem, Thomas; Lu, Zehuang H; Wang, Li J; Ertmer, Wolfgang; Friebe, Jan; Pape, Andrè; Rasel, Ernst-M; Riedmann, Mathias; Wübbena, Temmo

    2010-01-01

    We have explored the performance of 2 "dark fibers" of a commercial telecommunication fiber link for a remote comparison of optical clocks. These fibers establish a network in Germany that will eventually link optical frequency standards at PTB with those at the Institute of Quantum Optics (IQ) at the Leibniz University of Hanover, and the Max Planck Institutes in Erlangen (MPL) and Garching (MPQ). We demonstrate for the first time that within several minutes a phase coherent comparison of clock lasers at the few 10(-15) level can also be accomplished when the lasers are more than 100 km apart. Based on the performance of the fiber link to the IQ, we estimate the expected stability for the link from PTB to MPQ via MPL that bridges a distance of approximately 900 km.

  5. Urban Link Travel Time Estimation Based on Low Frequency Probe Vehicle Data

    Directory of Open Access Journals (Sweden)

    Xiyang Zhou

    2016-01-01

    Full Text Available To improve the accuracy and robustness of urban link travel time estimation with limited resources, this research developed a methodology to estimate the urban link travel time using low frequency GPS probe vehicle data. First, focusing on the case without reporting points for the GPS probe vehicle on the target link in the current estimation time window, a virtual report point creation model based on the K-Nearest Neighbour Rule was proposed. Then an improved back propagation neural network model was used to estimate the link travel time. The proposed method was applied to a case study based on an arterial road in Changchun, China: comparisons with the traditional artificial neural network method and the spatiotemporal moving average method revealed that the proposed method offered a higher estimation accuracy and better robustness.

  6. Extremely low frequency magnetic field measurements in buildings with transformer stations in Switzerland.

    Science.gov (United States)

    Röösli, Martin; Jenni, Daniela; Kheifets, Leeka; Mezei, Gabor

    2011-08-15

    The aim of this study was to evaluate an exposure assessment method that classifies apartments in three exposure categories of extremely low frequency magnetic fields (ELF-MF) based on the location of the apartment relative to the transformer room. We completed measurements in 39 apartments in 18 buildings. In each room of the apartments ELF-MF was concurrently measured with 5 to 6 EMDEX II meters for 10 min. Measured arithmetic mean ELF-MF was 0.59 μT in 8 apartments that were fully adjacent to a transformer room, either directly above the transformer or touching the transformer room wall-to-wall. In apartments that only partly touched the transformer room at corners or edges, average ELF-MF level was 0.14 μT. Average exposure in the remaining apartments was 0.10 μT. Kappa coefficient for exposure classification was 0.64 (95%-CI: 0.45-0.82) if only fully adjacent apartments were considered as highly exposed (>0.4 μT). We found a distinct ELF-MF exposure gradient in buildings with transformer. Exposure classification based on the location of the apartment relative to the transformer room appears feasible. Such an approach considerably reduces effort for exposure assessment and may be used to eliminate selection bias in future epidemiologic studies.

  7. In-field Raman amplification on coherent optical fiber links for frequency metrology.

    Science.gov (United States)

    Clivati, C; Bolognini, G; Calonico, D; Faralli, S; Mura, A; Levi, F

    2015-04-20

    Distributed Raman amplification (DRA) is widely exploited for the transmission of broadband, modulated signals used in data links, but not yet in coherent optical links for frequency metrology, where the requirements are rather different. After preliminary tests on fiber spools, in this paper we deeper investigate Raman amplification on deployed in-field optical metrological links. We actually test a Doppler-stabilized optical link both on a 94 km-long metro-network implementation with multiplexed ITU data channels and on a 180 km-long dedicated fiber haul connecting two cities, where DRA is employed in combination with Erbium-doped fiber amplification (EDFA). The performance of DRA is detailed in both experiments, indicating that it does not introduce noticeable penalties for the metrological signal or for the ITU data channels. We hence show that Raman amplification of metrological signals can be compatible with a wavelength division multiplexing architecture and that it can be used as an alternative or in combination with dedicated bidirectional EDFAs. No deterioration is noticed in the coherence properties of the delivered signal, which attains frequency instability at the 10(-19) level in both cases. This study can be of interest also in view of the undergoing deployment of continental fiber networks for frequency metrology.

  8. Transforming the Medical Subject Headings into Linked Data: Creating the Authorized Version of MeSH in RDF.

    Science.gov (United States)

    Bushman, Barbara; Anderson, David; Fu, Gang

    In February 2014 the National Library of Medicine formed the Linked Data Infrastructure Working Group to investigate the potential for publishing linked data, determine best practices for publishing linked data, and prioritize linked data projects, beginning with transforming the Medical Subject Headings as a linked data pilot. This article will review the pilot project to convert the Medical Subject Headings from XML to RDF. It will discuss the collaborative process, the technical and organizational issues tackled, and the future of linked data at the library.

  9. Compressive sensing-based channel bandwidth improvement in optical wireless orthogonal frequency division multiplexing link using visible light emitting diode.

    Science.gov (United States)

    Won, Yong-Yuk; Yoon, Sang Min

    2014-08-25

    A new technique, which can compensate for the lack of channel bandwidth in an optical wireless orthogonal frequency division multiplexing (OFDM) link based on a light emitting diode (LED), is proposed. It uses an adaptive sampling and an inverse discrete cosine transform in order to convert an OFDM signal into a sparse waveform so that not only is the important data obtained efficiently but the redundancy one is removed. In compressive sensing (CS), a sparse signal that is sampled below the Nyquist/Shannon limit can be reconstructed successively with enough measurement. This means that the CS technique can increase the data rate of visible light communication (VLC) systems based on LEDs. It is observed that the data rate of the proposed CS-based VLC-OFDM link can be made 1.7 times greater than a conventional VLC-OFDM link (from 30.72 Mb/s to 51.2 Mb/s). We see that the error vector magnitude (EVM) of the quadrature phase shift keying (QPSK) symbol is 31% (FEC limit: EVM of 32%) at a compression ratio of 40%.

  10. A Radio-Frequency-over-Fiber link for large-array radio astronomy applications

    CERN Document Server

    Mena, Juan; Cliche, Jean-Francois; Dobbs, Matt; Gilbert, Adam; Tang, Qing Yang

    2013-01-01

    A prototype 425-850 MHz Radio-Frequency-over-Fiber (RFoF) link for the Canadian Hydrogen Intensity Mapping Experiment (CHIME) is presented. The design is based on a directly modulated Fabry-Perot (FP) laser, operating at ambient temperature, and a single-mode fiber. The dynamic performance, gain stability, and phase stability of the RFoF link are characterized. Tests on a two-element interferometer built at the Dominion Radio Astrophysical Observatory for CHIME prototyping demonstrate that RFoF can be successfully used as a cost-effective solution for analog signal transport on the CHIME telescope and other large-array radio astronomy applications

  11. Wavelet packet transform-based optical orthogonal frequency-division multiplexing transmission using direct detection

    Science.gov (United States)

    Zhang, Hongbo; Yi, Xingwen; Chen, Lei; Zhang, Jing; Deng, Mingliang; Qiu, Kun

    2012-10-01

    As an alternate to fast Fourier transform-based orthogonal frequency-division multiplexing (OFDM), wavelet packet transform (WPT)-based OFDM (WPT-OFDM) does not require cyclic prefix to avoid inter-symbol-interference. The wavelet has many varieties and therefore, it can provide more freedom for system design to suit different applications. We propose a real-valued WPT-OFDM that uses intensity modulation/direct detection. We also conduct an experiment to verify its performance through a 75-km standard single-mode fiber.

  12. Core influence on the frequency response analysis (FRA of power transformers through the finite element method

    Directory of Open Access Journals (Sweden)

    D. L. Alvarez

    2015-11-01

    Full Text Available In this paper the influence of core parameters in Frequency Response Analysis is analyzed through the equivalent circuit impedance matrix of the transformer winding; the parameters of the circuit have been computed using the Finite Element Method. In order to appreciate the behavior of the iron core in comparison to the air core, the frequency dependence of resonances is calculated to show how the air core only influences the results at low frequencies. The core is modeled using a complex permeability, and the parameters of conductivity and permeability are varied to show their influence in the resonances, which turned out to be negligible. In order to explain this behavior, the eigenvalues of the inverse impedance matrix are calculated showing that they are similar for different values of conductivity and permeability. Finally, the magnetic flux inside and outside the core and its influence in the frequency response is studied.

  13. Off-resonance frequency operation for power transfer in a loosely coupled air core transformer

    Science.gov (United States)

    Scudiere, Matthew B

    2012-11-13

    A power transmission system includes a loosely coupled air core transformer having a resonance frequency determined by a product of inductance and capacitance of a primary circuit including a primary coil. A secondary circuit is configured to have a substantially same product of inductance and capacitance. A back EMF generating device (e.g., a battery), which generates a back EMF with power transfer, is attached to the secondary circuit. Once the load power of the back EMF generating device exceeds a certain threshold level, which depends on the system parameters, the power transfer can be achieved at higher transfer efficiency if performed at an operating frequency less than the resonance frequency, which can be from 50% to 95% of the resonance frequency.

  14. Detailed High Frequency Models of Various Winding Types in Power Transformers

    DEFF Research Database (Denmark)

    Pedersen, Kenneth; Lunow, Morten Erlandsson; Holbøll, Joachim

    2005-01-01

    of a single transformer leg, including all turns and windings. From the input data a three phase equivalent circuit is calculated and corresponding nodal impedance matrices are found for appropriate frequencies. Vector fitting is then applied which produces an excellent rational function approximation...... to the nodal impedance matrix in the valid frequency range. From the approximation an equivalent circuit can be extracted and implemented in circuit simulation software. A small but novel step makes it possible to compute not only the voltage distribution but also the internal currents from the extracted...

  15. Correspondence between phasor transforms and frequency response function in RLC circuits

    CERN Document Server

    Abdalla, Hassan Mohamed Abdelalim

    2016-01-01

    The analysis of RLC circuits is usually made by considering phasor transforms of sinusoidal signals (characterized by constant amplitude, period and phase) that allow the calculation of the AC steady state of RLC circuits by solving simple algebraic equations. In this paper I try to show that phasor representation of RLC circuits is analogue to consider the frequency response function (commonly designated by FRF) of the total impedance of the circuit. In this way I derive accurate expressions for the resonance and anti-resonance frequencies and their corresponding values of impedances of the parallel and series RLC circuits respectively, notwithstanding the presence of damping effects.

  16. Superconducting multiturn flux transformers for radio frequency superconducting quantum interference devices

    OpenAIRE

    Yi, H. R.; Zhang, Y; Schubert, J.; Zander, W.; Zeng, X. H.; Klein, N

    2000-01-01

    This article describes three planar layouts of superconducting multiturn flux transformers integrated with a coplanar resonator for radio frequency (rf) superconducting quantum interference device (SQUID) magnetometers. The best magnetic field noise values of 22 and 11.5 fT/Hz(1/2) in the white noise regime were obtained for the layout with two input coils and the layout with the labyrinth resonator, respectively. Excess low-frequency noise (about 200 fT/Hz(1/2) at 10 Hz) was present. Compute...

  17. Frequency domain volume rendering by the wavelet X-ray transform.

    Science.gov (United States)

    Westenberg, M A; Roerdink, J M

    2000-01-01

    We describe a wavelet based X-ray rendering method in the frequency domain with a smaller time complexity than wavelet splatting. Standard Fourier volume rendering is summarized and interpolation and accuracy issues are briefly discussed. We review the implementation of the fast wavelet transform in the frequency domain. The wavelet X-ray transform is derived, and the corresponding Fourier-wavelet volume rendering algorithm (FWVR) is introduced, FWVR uses Haar or B-spline wavelets and linear or cubic spline interpolation. Various combinations are tested and compared with wavelet splatting (WS). We use medical MR and CT scan data, as well as a 3-D analytical phantom to assess the accuracy, time complexity, and memory cost of both FWVR and WS. The differences between both methods are enumerated.

  18. State of art survey for design of medium frequency high power transformer

    DEFF Research Database (Denmark)

    Vaisambhayana, Sriram; Dincan, Catalin; Shuyu, Cao

    2016-01-01

    Medium and high frequency, high power transformers play an important role in footprint reduction along with their functions of galvanic isolation, and voltage transformation in all high power converters typically used in traction power systems, offshore wind plant power converters, and solid state...... in the literature are described, and some design procedures and flow charts are analyzed including specific optimization routines. Estimation of core loss at high frequency using Steinmetz method and other modified methods are shown in detail. Thermal modelling including static and dynamic methods available...... in literature are put forward with references to thermal management methods. FEM analysis for electromagnetic behavior is described and couple of commercially available tools and their limitations are analyzed. Different challenges of relevance are included in different sections and brief comparisons are drawn...

  19. Magnetic resonance spectral reconstruction using frequency-shifted and summed Fourier transform processing

    Science.gov (United States)

    Clark, W. G.; Hanson, M. E.; Lefloch, F.; Ségransan, P.

    1995-03-01

    A novel method of Fourier transform spectroscopy of the transient signals from wide, inhomogeneously broadened magnetic resonance spectra is described and analyzed. It has the advantages of high resolution, high sensitivity, and freedom from the distortions introduced by the finite amplitude of the pulsed rf magnetic field and the finite bandwidth of the receiving system. It consists of recording the transient signal at a series of magnetic fields, shifting the frequency of the transient by the corresponding field step for each point, and summing the corresponding Fourier transformed signals. Although the primary emphasis is on pulsed NMR, the analysis also applies to pulsed ESR. Criteria for the range and step interval of the magnetic field variation are discussed. The accuracy and sensitivity of the method are compared with earlier methods of spin echo spectroscopy. A description of the corresponding measurement of NQR, NMR, and ESR spectra obtained by stepping the frequency of the spectrometer is also presented.

  20. Condition assessment of transformer insulation using dielectric frequency response analysis by artificial bee colony algorithm

    Directory of Open Access Journals (Sweden)

    Bigdeli Mehdi

    2016-03-01

    Full Text Available Transformers are one of the most important components of the power system. It is important to maintain and assess the condition. Transformer lifetime depends on the life of its insulation and insulation life is also strongly influenced by moisture in the insulation. Due to importance of this issue, in this paper a new method is introduced for determining the moisture content of the transformer insulation system using dielectric response analysis in the frequency domain based on artificial bee colony algorithm. First, the master curve of dielectric response is modeled. Then, using proposed method the master curve and the measured dielectric response curves are compared. By analyzing the results of the comparison, the moisture content of paper insulation, electrical conductivity of the insulating oil and dielectric model dimensions are determined. Finally, the proposed method is applied to several practical samples to demonstrate its capabilities compared with the well-known conventional method.

  1. New Configuration of Traction Converter with Medium-Frequency Transformer: Primary Part

    Directory of Open Access Journals (Sweden)

    Vojtech Blahnik

    2008-01-01

    Full Text Available This paper deals with new configuration of the traction converter with medium-frequency transformer intended for ac trolley wire fed locomotives. It is concerned to the primary serially connected single-phase voltage-source active rectifiers, which are directly connected to the trolley wire. This contribution presents the proposed control of the primary active rectifiers, simulation and experimental results of designed low-voltage laboratory prototype of converter of rated power of 12kW.

  2. Fourier Transform Ion Cyclotron Resonance Mass Spectrometry at the Cyclotron Frequency

    Science.gov (United States)

    Nagornov, Konstantin O.; Kozhinov, Anton N.; Tsybin, Yury O.

    2017-02-01

    The phenomenon of ion cyclotron resonance allows for determining mass-to-charge ratio, m/z, of an ensemble of ions by means of measurements of their cyclotron frequency, ω c . In Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), the ω c quantity is usually unavailable for direct measurements: the resonant state is located close to the reduced cyclotron frequency (ω+), whereas the ω c and the corresponding m/z values may be calculated via theoretical derivation from an experimental estimate of the ω+ quantity. Here, we describe an experimental observation of a new resonant state, which is located close to the ω c frequency and is established because of azimuthally-dependent trapping electric fields of the recently developed ICR cells with narrow aperture detection electrodes. We show that in mass spectra, peaks close to ω+ frequencies can be reduced to negligible levels relative to peaks close to ω c frequencies. Due to reduced errors with which the ω c quantity is obtained, the new resonance provides a means of cyclotron frequency measurements with precision greater than that achieved when ω+ frequency peaks are employed. The described phenomenon may be considered for a development into an FT-ICR MS technology with increased mass accuracy for applications in basic research, life, and environmental sciences.

  3. Reference Beam Pattern Design for Frequency Invariant Beamforming Based on Fast Fourier Transform.

    Science.gov (United States)

    Zhang, Wang; Su, Tao

    2016-09-22

    In the field of fast Fourier transform (FFT)-based frequency invariant beamforming (FIB), there is still an unsolved problem. That is the selection of the reference beam to make the designed wideband pattern frequency invariant (FI) over a given frequency range. This problem is studied in this paper. The research shows that for a given array, the selection of the reference beam pattern is determined by the number of sensors and the ratio of the highest frequency to the lowest frequency of the signal (RHL). The length of the weight vector corresponding to a given reference beam pattern depends on the reference frequency. In addition, the upper bound of the weight length to ensure the FI property over the whole frequency band of interest is also given. When the constraints are added to the reference beam, it does not affect the FI property of the designed wideband beam as long as the symmetry of the reference beam is ensured. Based on this conclusion, a scheme for reference beam design is proposed.

  4. Fourier Transform Ion Cyclotron Resonance Mass Spectrometry at the Cyclotron Frequency.

    Science.gov (United States)

    Nagornov, Konstantin O; Kozhinov, Anton N; Tsybin, Yury O

    2017-04-01

    The phenomenon of ion cyclotron resonance allows for determining mass-to-charge ratio, m/z, of an ensemble of ions by means of measurements of their cyclotron frequency, ω c . In Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), the ω c quantity is usually unavailable for direct measurements: the resonant state is located close to the reduced cyclotron frequency (ω+), whereas the ω c and the corresponding m/z values may be calculated via theoretical derivation from an experimental estimate of the ω+ quantity. Here, we describe an experimental observation of a new resonant state, which is located close to the ω c frequency and is established because of azimuthally-dependent trapping electric fields of the recently developed ICR cells with narrow aperture detection electrodes. We show that in mass spectra, peaks close to ω+ frequencies can be reduced to negligible levels relative to peaks close to ω c frequencies. Due to reduced errors with which the ω c quantity is obtained, the new resonance provides a means of cyclotron frequency measurements with precision greater than that achieved when ω+ frequency peaks are employed. The described phenomenon may be considered for a development into an FT-ICR MS technology with increased mass accuracy for applications in basic research, life, and environmental sciences. Graphical Abstract ᅟ.

  5. An Intelligent Sensor for the Ultra-High-Frequency Partial Discharge Online Monitoring of Power Transformers

    Directory of Open Access Journals (Sweden)

    Jian Li

    2016-05-01

    Full Text Available Ultra-high-frequency (UHF partial discharge (PD online monitoring is an effective way to inspect potential faults and insulation defects in power transformers. The construction of UHF PD online monitoring system is a challenge because of the high-frequency and wide-frequency band of the UHF PD signal. This paper presents a novel, intelligent sensor for UHF PD online monitoring based on a new method, namely a level scanning method. The intelligent sensor can directly acquire the statistical characteristic quantities and is characterized by low cost, few data to output and transmit, Ethernet functionality, and small size for easy installation. The prototype of an intelligent sensor was made. Actual UHF PD experiments with three typical artificial defect models of power transformers were carried out in a laboratory, and the waveform recording method and intelligent sensor proposed were simultaneously used for UHF PD measurement for comparison. The results show that the proposed intelligent sensor is qualified for the UHF PD online monitoring of power transformers. Additionally, three methods to improve the performance of intelligent sensors were proposed according to the principle of the level scanning method.

  6. Linked Learning as a High School Transformation Strategy: Organizational Structures and Leadership Behaviors That Support Lasting Change

    Science.gov (United States)

    Weiss, Elizabeth Rocio

    2016-01-01

    Linked Learning is an approach that has proven effective in transforming the learning experiences for high school students. An instrumental case study was conducted in a large urban district in Southern California where district and school leaders implemented Linked Learning as a systemic high school reform initiative. Analysis of the data…

  7. Linked Learning as a High School Transformation Strategy: Organizational Structures and Leadership Behaviors That Support Lasting Change

    Science.gov (United States)

    Weiss, Elizabeth Rocio

    2016-01-01

    Linked Learning is an approach that has proven effective in transforming the learning experiences for high school students. An instrumental case study was conducted in a large urban district in Southern California where district and school leaders implemented Linked Learning as a systemic high school reform initiative. Analysis of the data…

  8. On the Link Between Benevolent Sexism and Orgasm Frequency in Heterosexual Women.

    Science.gov (United States)

    Harris, Emily Ann; Hornsey, Matthew J; Barlow, Fiona Kate

    2016-11-01

    Previous research on subclinical orgasmic difficulties among women has focused on intrapsychic and interpersonal variables, but little attention has been paid to the more distal ideological factors that might indirectly constrain sexual pleasure. We hypothesized that women's endorsement of a benevolently sexist worldview would be negatively associated with orgasm frequency. Specifically, we predicted that benevolent sexism would be associated with increased perceptions of male sexual selfishness. This perception of men as interested in their own sexual pleasure would then predict decreased willingness to ask a partner for sexual pleasure, which in turn would be associated with less frequent orgasms. We found support for our model across two studies (Study 1: N = 339; Study 2: N = 323). We did not, however, find a direct effect of benevolent sexism on orgasm frequency. We discuss possible additional variables linking benevolent sexism with orgasm frequency, implications, and future directions.

  9. Joint time and frequency dissemination network over delay-stabilized fiber optic links

    CERN Document Server

    Chen, Wei; Cheng, Nan; Xu, Dan; Yang, Fei; Gui, Youzhen; Cai, Haiwen

    2015-01-01

    A precise fiber-based time and frequency dissemination scheme for multiple users with a tree-like branching topology is proposed. Through this scheme, ultra-stable signals can be easily accessed online anywhere along the fiber without affecting other sites. The scheme is tested through an experiment, in which a modulated frequency signal and a synchronized time signal are transferred to multiple remote sites over a delay-stabilized fiber optic links that are over 50 km long. Results show that the relative stabilities are 5E-14@1s and 2E-17@10000s. Meanwhile, compared with each site, time synchronization precision is less than 80 ps. These results can pave the way to practical applications in joint time and frequency dissemination network systems.

  10. Sub-nanosecond machine timing and frequency distribution via serial data links

    CERN Document Server

    Rohlev, A; Serrano, J; Cattin, M; Settler, M

    2008-01-01

    FERMI@ELETTRA is a 4th generation light source under construction at Sincrotrone Trieste. It will be operated as a seeded FEL driven by a warm S-band Linac which places very stringent specifications on control of the amplitude and phase of the RF stations. The local clock generation and distribution system at each station will not be based on the phase reference distribution but rather on a separate frequency reference distribution which has significantly less stringent phase stability requirements. This frequency reference will be embedded in the serial data link to each station and has the further advantage of being able to broadcast synchronous machine timing signals with sub-nanosecond temporal accuracy. The phase and amplitude of the phase reference line is measured for each pulse and used to calibrate the other measurements. This paper describes the architecture used to distribute the frequency reference along with the precision machine timing and clocking signals.

  11. Spatial transformation-enabled electromagnetic devices: from radio frequencies to optical wavelengths.

    Science.gov (United States)

    Jiang, Zhi Hao; Turpin, Jeremy P; Morgan, Kennith; Lu, Bingqian; Werner, Douglas H

    2015-08-28

    Transformation optics provides scientists and engineers with a new powerful design paradigm to manipulate the flow of electromagnetic waves in a user-defined manner and with unprecedented flexibility, by controlling the spatial distribution of the electromagnetic properties of a medium. Using this approach, over the past decade, various previously undiscovered physical wave phenomena have been revealed and novel electromagnetic devices have been demonstrated throughout the electromagnetic spectrum. In this paper, we present versatile theoretical and experimental investigations on designing transformation optics-enabled devices for shaping electromagnetic wave radiation and guidance, at both radio frequencies and optical wavelengths. Different from conventional coordinate transformations, more advanced and versatile coordinate transformations are exploited here to benefit diverse applications, thereby providing expanded design flexibility, enhanced device performance, as well as reduced implementation complexity. These design examples demonstrate the comprehensive capability of transformation optics in controlling electromagnetic waves, while the associated novel devices will open up new paths towards future integrated electromagnetic component synthesis and design, from microwave to optical spectral regimes. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  12. Time frequency characterization of hand-transmitted, impulsive vibrations using analytic wavelet transform

    Science.gov (United States)

    Kim, Jay; Welcome, Daniel E.; Dong, Ren G.; Joon Song, Won; Hayden, Charles

    2007-11-01

    Current guidelines to assess health risk of hand-arm vibration are based on the frequency-weighted rms acceleration level, therefore do not fully consider the effect of temporal variations of the spectral energy. Time averaging effect involved with the frequency analysis may severely underestimate the risk of impact tools. A time-frequency ( T- F) analysis is necessary to characterize a highly transient signal whose spectral characteristics change rapidly in time. The analytic wavelet transform (AWT) is an ideal T- F analysis tool as it possesses the advantages of both the Fourier and wavelet transforms. The AWT is applied to acceleration signals measured from six tools, five impact type tools and one relatively steady-type tool, to explore possible improvements of the current risk assessment method of hand-arm vibration exposure. Based on the unique capability of the AWT, several new concepts including frequency-weighted time history, cumulative injury function, and cumulative injury index are defined in this study. Possible applications of these new concepts to hand-arm vibration research are described. Based on the results from this study, needs for future research are discussed.

  13. Analysis of Signals with Fast-Varying Instantaneous Frequency: Window Selection and Insights from Synchrosqueezing Transform

    CERN Document Server

    Sheu, Yae-lin; Wu, Hau-tieng

    2015-01-01

    We develop a theory for analyzing a signal that consists of multiple oscillatory components with fast-varying instantaneous frequencies. In order to describe this kind of signals, the adaptive harmonic model is extended to include fast-varying instantaneous frequency components. Moreover, we apply the Renyi entropy to measure the time-frequency representation provided by synchrosqueezing transform and determine an optimal window width. For a signal with multiple components, which induce coupling artifacts, we propose an adaptive optimal window approach by segmenting the signal into several sections. Examples presented include a synthetic signal and an application to attosecond physics considering the atomic time-varying dipole moment driven by a two-color midinfrared laser fields.

  14. Estimation of Transformer Winding Capacitances through Frequency Response Analysis - An Experimental Investigation

    Science.gov (United States)

    Shah, Krupa; Ragavan, K.

    2013-10-01

    This article focuses on developing a non-invasive method for determining capacitances using frequency response data. The proposed methodology involves acquiring driving-point impedance of the winding under consideration over wide frequency range. With certain terminal conditions and using the terminal impedance measured at specific frequencies, input and shunt capacitances are determined. For the purpose of estimating series capacitance of the winding, an algorithm is proposed. To demonstrate the capability of the method, initially model coils that have provisions for connecting external capacitances are considered. Then, it is found that the estimated values of capacitances are nearly same as those of connected capacitances. The method is, then, extended to transformer winding, and a capacitive ladder network is constructed. To assess the accuracy of estimation, capacitive voltage distribution is utilized. That is, the voltage distribution in the winding is compared with that of synthesized circuit. A good agreement between those data reveals that the estimated capacitance values are accurate.

  15. Linking magma reservoir processes to the frequency and magnitude of volcanic eruptions

    Science.gov (United States)

    Sheldrake, Tom; Caricchi, Luca

    2016-04-01

    The frequency of volcanic eruptions is fundamentally related to processes controlling the accumulation of eruptible magma at depth and the pressurisation of the magmatic reservoir. Here we present a combined statistical-empirical approach to link the frequency and magnitude of volcanic eruptions observed in different arcs to important parameters controlling the growth of subvolcanic reservoirs of eruptible magma. Such understanding is important for two reasons; firstly it presents an insight into how and why the frequency of eruptions varies between different groups of volcanoes; and secondly, it provides constraints for models that are used to interpret geochemical and geophysical data. To perform the analysis we further develop an analytical model that uses a Monte Carlo sampling approach to simulate the accumulation and eruption of magmatic reservoirs (Caricchi et al., 2014). By inverting the geological record of volcanic eruptions we can solve the Monte Carlo model to quantify parameters such as magma input and frequency of magma injection. Our results indicate systematic variation in the frequency of eruptions of various magnitudes between exchangeable groups of volcanoes, which can be related to variations of parameters such as average magma fluxes and thickness of the crust. Caricchi, L., C. Annen, J. Blundy, G. Simpson, and V. Pinel, 2014, Nature Geoscience, v. 7, no. 2, p. 126-130, doi:10.1038/ngeo2041.

  16. Separation of overlapping linear frequency modulated (LFM) signals using the fractional fourier transform.

    Science.gov (United States)

    Cowell, David M J; Freear, Steven

    2010-10-01

    Linear frequency modulated (LFM) excitation combined with pulse compression provides an increase in SNR at the receiver. LFM signals are of longer duration than pulsed signals of the same bandwidth; consequently, in many practical situations, maintaining temporal separation between echoes is not possible. Where analysis is performed on individual LFM signals, a separation technique is required. Time windowing is unable to separate signals overlapping in time. Frequency domain filtering is unable to separate signals with overlapping spectra. This paper describes a method to separate time-overlapping LFM signals through the application of the fractional Fourier transform (FrFT), a transform operating in both time and frequency domains. A short introduction to the FrFT and its operation and calculation are presented. The proposed signal separation method is illustrated by application to a simulated ultrasound signal, created by the summation of multiple time-overlapping LFM signals and the component signals recovered with ±0.6% spectral error. The results of an experimental investigation are presented in which the proposed separation method is applied to time-overlapping LFM signals created by the transmission of a LFM signal through a stainless steel plate and water-filled pipe.

  17. Studies of Improving the Frequency of Indica Rice Transformation by Biolistic Bombardment

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In order to improve the frequency of indica rice transformation by biolistic bombardment, suitable culture conditions for embryonic calli,an optimal selection scheme for resistant calli and seedlings, and optimum bombardment parameters a investigated by using 14 commercially important indica rice cultivars. The main results show that the CC medium with 36g/L mannitol is a scheme subculture medium in which the browning of indica rice calli can be mitigated significantly; The concentration of 30~40mg/L Hyg or 150~200mg/L G418 or 10~20 mg/L Basta is suitable for selection of resistant calli; The transformation parameters of 100μg gold powder absorbing 0.2μg DNA per shot and 900 psi helium pressure and 6 cm bombardment distance and bombarded twice for each plate give the best result; Keeping the target calli on osmotic medium containing 60g/L mannitol from 12 ~24h before bombardment to 24~48h after it can increase the efficiencies of transformation . Furthermore, some transgenic indica rice plants are obtained using this optimized transformation system.

  18. Implementation guidance for industrial-level security systems using radio frequency alarm links

    Energy Technology Data Exchange (ETDEWEB)

    Swank, R.G.

    1996-07-12

    Spread spectrum (SS) RF transmission technologies have properties that make the transmitted signal difficult to intercept, interpret, and jam. The digital code used in the modulation process results in a signal that has high reception reliability and supports multiple use of frequency bands and selective addressing. These attributes and the relatively low installation cost of RF systems make SSRF technologies candidate for communications links in security systems used for industrial sites, remote locations, and where trenching or other disturbances of soil or structures may not be desirable or may be costly. This guide provides a description of such a system and presents implementation methods that may be of engineering benefit.

  19. Surpassing the Path-Limited Resolution of a Fourier Transform Spectrometer with Frequency Combs

    CERN Document Server

    Maslowski, Piotr; Johansson, Alexandra C; Khodabakhsh, Amir; Kowzan, Grzegorz; Rutkowski, Lucile; Mills, Andrew A; Mohr, Christian; Jiang, Jie; Fermann, Martin E; Foltynowicz, Aleksandra

    2015-01-01

    Fourier transform spectroscopy based on incoherent light sources is a well-established tool in research fields from molecular spectroscopy and atmospheric monitoring to material science and biophysics. It provides broadband molecular spectra and information about the molecular structure and composition of absorptive media. However, the spectral resolution is fundamentally limited by the maximum delay range ({\\Delta}$_{max}$) of the interferometer, so acquisition of high-resolution spectra implies long measurement times and large instrument size. We overcome this limit by combining the Fourier transform spectrometer with an optical frequency comb and measuring the intensities of individual comb lines by precisely matching the {\\Delta}$_{max}$ to the comb line spacing. This allows measurements of absorption lines narrower than the nominal (optical path-limited) resolution without ringing effects from the instrumental lineshape and reduces the acquisition time and interferometer length by orders of magnitude.

  20. Transformed eddy-PV flux and positive synoptic eddy feedback onto low-frequency flow

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Hong-Li [University of Hawaii, School of Ocean and Earth Sciences and Technology, Honolulu, HI (United States); China Meteorological Administration, Laboratory for Climate Studies, National Climate Center, Beijing (China); Jin, Fei-Fei [University of Hawaii, School of Ocean and Earth Sciences and Technology, Honolulu, HI (United States); Kug, Jong-Seong [Korea Ocean Research and Development Institute, Ansan (Korea, Republic of); Gao, Li [University of Hawaii, School of Ocean and Earth Sciences and Technology, Honolulu, HI (United States); China Meteorological Administration, Numerical Prediction Center, National Meteorological Center, Beijing (China)

    2011-06-15

    Interaction between synoptic eddy and low-frequency flow (SELF) has been the subject of many studies. In this study, we further examine the interaction by introducing a transformed eddy-potential-vorticity (TEPV) flux that is obtained from eddy-potential-vorticity flux through a quasi-geostrophic potential-vorticity inversion. The main advantage of using the TEPV flux is that it combines the effects of the eddy-vorticity and heat fluxes into the net acceleration of the low-frequency flow in such a way that the TEPV flux tends to be analogous to the eddy-vorticity fluxes in the barotropic framework. We show that the anomalous TEPV fluxes are preferentially directed to the left-hand side of the low-frequency flow in all vertical levels throughout the troposphere for monthly flow anomalies and for climate modes such as the Arctic Oscillation (AO). Furthermore, this left-hand preference of the TEPV flux direction is a convenient three-dimensional indicator of the positive reinforcement of the low-frequency flow by net eddy-induced acceleration. By projecting the eddy-induced net accelerations onto the low-frequency flow anomalies, we estimate the eddy-induced growth rates for the low frequency flow anomalies. This positive eddy-induced growth rate is larger (smaller) in the lower (upper) troposphere. The stronger positive eddy feedback in the lower troposphere may play an important role in maintaining an equivalent barotropic structure of the low-frequency atmospheric flow by balancing some of the strong damping effect of surface friction. (orig.)

  1. Transformed eddy-PV flux and positive synoptic eddy feedback onto low-frequency flow

    Science.gov (United States)

    Ren, Hong-Li; Jin, Fei-Fei; Kug, Jong-Seong; Gao, Li

    2011-06-01

    Interaction between synoptic eddy and low-frequency flow (SELF) has been the subject of many studies. In this study, we further examine the interaction by introducing a transformed eddy-potential-vorticity (TEPV) flux that is obtained from eddy-potential-vorticity flux through a quasi-geostrophic potential-vorticity inversion. The main advantage of using the TEPV flux is that it combines the effects of the eddy-vorticity and heat fluxes into the net acceleration of the low-frequency flow in such a way that the TEPV flux tends to be analogous to the eddy-vorticity fluxes in the barotropic framework. We show that the anomalous TEPV fluxes are preferentially directed to the left-hand side of the low-frequency flow in all vertical levels throughout the troposphere for monthly flow anomalies and for climate modes such as the Arctic Oscillation (AO). Furthermore, this left-hand preference of the TEPV flux direction is a convenient three-dimensional indicator of the positive reinforcement of the low-frequency flow by net eddy-induced acceleration. By projecting the eddy-induced net accelerations onto the low-frequency flow anomalies, we estimate the eddy-induced growth rates for the low frequency flow anomalies. This positive eddy-induced growth rate is larger (smaller) in the lower (upper) troposphere. The stronger positive eddy feedback in the lower troposphere may play an important role in maintaining an equivalent barotropic structure of the low-frequency atmospheric flow by balancing some of the strong damping effect of surface friction.

  2. Transformation optics: a time- and frequency-domain analysis of electron-energy loss spectroscopy

    CERN Document Server

    Kraft, Matthias; Pendry, J B

    2016-01-01

    Electron energy loss spectroscopy (EELS) and Cathodoluminescence (CL) play a pivotal role in many of the cutting edge experiments in plasmonics. EELS and CL experiments are usually supported by numerical simulations, which, whilst accurate, may not provide as much physical insight as analytical calculations do. Fully analytical solutions to EELS and CL systems in plasmonics are rare and difficult to obtain. This paper aims to narrow this gap by introducing a new method based on Transformation optics that allows to calculate the quasi-static frequency and time-domain response of plasmonic particles under electron beam excitation.

  3. A WEIGHTED GENERAL DISCRETE FOURIER TRANSFORM FOR THE FREQUENCY-DOMAIN BLIND SOURCE SEPARATION OF CONVOLUTIVE MIXTURES

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This letter deals with the frequency domain Blind Source Separation of Convolutive Mixtures(CMBSS).From the frequency representation of the"overlap and save",a Weighted General Discrete Fourier Transform (WGDFT) is derived to replace the traditional Discrete Fourier Transform (DFT).The mixing matrix on each frequency bin could be estimated more precisely from WGDFT coefficients than from DFT coefficients,which improves separation performance.Simulation results verify the validity of WGDFT for frequency domain blind source separation of convolutive mixtures.

  4. A Novel Application of Fourier Transform Spectroscopy with HEMT Amplifiers at Microwave Frequencies

    Science.gov (United States)

    Wilkinson, David T.; Page, Lyman

    1995-01-01

    The goal was to develop cryogenic high-electron-mobility transistor (HEMT) based radiometers and use them to measure the anisotropy in the cosmic microwave background (CMB). In particular, a novel Fourier transform spectrometer (FTS) built entirely of waveguide components would be developed. A dual-polarization Ka-band HEMT radiometer and a similar Q-band radiometer were built. In a series of measurements spanning three years made from a ground-based site in Saskatoon, SK, the amplitude, frequency spectrum, and spatial frequency spectrum of the anisotropy were measured. A prototype Ka-band FTS was built and tested, and a simplified version is proposed for the MAP satellite mission. The 1/f characteristics of HEMT amplifiers were quantified using correlation techniques.

  5. An automatic frequency control loop using overlapping DFTs (Discrete Fourier Transforms)

    Science.gov (United States)

    Aguirre, S.

    1988-01-01

    An automatic frequency control (AFC) loop is introduced and analyzed in detail. The new scheme is a generalization of the well known Cross Product AFC loop that uses running overlapping discrete Fourier transforms (DFTs) to create a discriminator curve. Linear analysis is included and supported with computer simulations. The algorithm is tested in a low carrier to noise ratio (CNR) dynamic environment, and the probability of loss of lock is estimated via computer simulations. The algorithm discussed is a suboptimum tracking scheme with a larger frequency error variance compared to an optimum strategy, but offers simplicity of implementation and a very low operating threshold CNR. This technique can be applied during the carrier acquisition and re-acquisition process in the Advanced Receiver.

  6. Automating identification of avian vocalizations using time-frequency information extracted from the Gabor transform.

    Science.gov (United States)

    Connor, Edward F; Li, Shidong; Li, Steven

    2012-07-01

    Based on the Gabor transform, a metric is developed and applied to automatically identify bird species from a sample of 568 digital recordings of songs/calls from 67 species of birds. The Gabor frequency-amplitude spectrum and the Gabor time-amplitude profile are proposed as a means to characterize the frequency and time patterns of a bird song. An approach based on template matching where unknown song clips are compared to a library of known song clips is used. After adding noise to simulate the background environment and using an adaptive high-pass filter to de-noise the recordings, the successful identification rate exceeded 93% even at signal-to-noise ratios as low as 5 dB. Bird species whose songs/calls were dominated by low frequencies were more difficult to identify than species whose songs were dominated by higher frequencies. The results suggest that automated identification may be practical if comprehensive libraries of recordings that encompass the vocal variation within species can be assembled.

  7. Transformation of the frequency-modulated continuous-wave field into a train of short pulses by resonant filters

    CERN Document Server

    Shakhmuratov, R N

    2016-01-01

    The resonant filtering method transforming frequency modulated radiation field into a train of short pulses is proposed to apply in optical domain. Effective frequency modulation can be achieved by electro-optic modulator or by resonant frequency modulation of the filter with a narrow absorption line. Due to frequency modulation narrow-spectrum CW radiation field is seen by the resonant filter as a comb of equidistant spectral components separated by the modulation frequency. Tuning narrow-bandwidth filter in resonance with $n$-th spectral component of the comb transforms the radiation field into bunches of pulses with $n$ pulses in each bunch. The transformation is explained by the interference of the coherently scattered resonant component of the field with the whole comb. Constructive interference results in formation of pulses, while destructive interference is seen as dark windows between pulses. It is found that the optimal thickness of the resonant filter is several orders of magnitude smaller than the...

  8. Generalized stepwise demodulation transform and synchrosqueezing for time-frequency analysis and bearing fault diagnosis

    Science.gov (United States)

    Shi, Juanjuan; Liang, Ming; Necsulescu, Dan-Sorin; Guan, Yunpeng

    2016-04-01

    The energy concentration level is an important indicator for time-frequency analysis (TFA). Weak energy concentration would result in time-frequency representation (TFR) diffusion and thus leading to ambiguous results or even misleading signal analysis results, particularly for nonstationary multicomponent signals. To improve the energy concentration level, this paper proposes a generalized stepwise demodulation transform (GSDT). The rationale of the proposed method is that (1) the generalized demodulation (GD) can map the original signal into an analytic signal with constant instantaneous frequency (IF) and improve the energy concentration level on time-frequency plane, and (2) focusing on a short window around the time instant of interest, a backward demodulation operation can recover the original frequency at the time instant without affecting the improved energy concentration level. By repeating the backward demodulation at every time instant of interest, the TFR of the entire signal can be attained with enhanced energy concentration level. With the GSDT, an iterative GSDT (IGSDT) is developed to analyze multicomponent signal that is subjected to different modulating sources for their constituent components. The IGSDT iteratively demodulates each constituent component to attain its TFR and the TFR of the whole signal is derived from superposing all the resulting TFRs of constituent components. The cross-term free and more energy concentrated TFR of the signal is, therefore, obtained, and the diffusion in the TFR can be reduced. The GSDT-based synchrosqueezing transform is also elaborated to further enhance the GSDT(IGSDT) yielded TFR. The effectiveness of the proposed method in TFA is tested using both simulated monocomponent and multicomponent signals. The application of the proposed method to bearing fault detection is explored. Bearing condition and fault pattern can be revealed by the proposed method resulting TFR. The main advantages of the proposed method

  9. Linking the thermodynamic temperature to an optical frequency: recent advances in Doppler broadening thermometry

    Science.gov (United States)

    2016-01-01

    Laser spectroscopy in the linear regime of radiation–matter interaction is a powerful tool for measuring thermodynamic quantities in a gas at thermodynamic equilibrium. In particular, the Doppler effect can be considered a gift of nature, linking the thermal energy to an optical frequency, namely the line centre frequency of an atomic or molecular spectral line. This is the basis of a relatively new method of primary gas thermometry, known as Doppler broadening thermometry (DBT). This paper reports on the efforts that have been carried out, in the last decade, worldwide, to the end of making DBT competitive with more consolidated and accurate methodologies, such as acoustic gas thermometry and dielectric constant gas thermometry. The main requirements for low-uncertainty DBT, of both theoretical and technical nature, will be discussed, with a special focus on those related to the line shape model and to the frequency scale. A deep comparison among the different molecules that have been selected in successful DBT implementations is also reported. Finally, for the first time, to the best of my knowledge, the influence of refractive index effects is discussed. PMID:26903093

  10. Linking transformational leadership to nurses' extra-role performance: the mediating role of self-efficacy and work engagement.

    Science.gov (United States)

    Salanova, Marisa; Lorente, Laura; Chambel, Maria J; Martínez, Isabel M

    2011-10-01

    This paper is a report of a social cognitive theory-guided study about the link between supervisors' transformational leadership and staff nurses' extra-role performance as mediated by nurse self-efficacy and work engagement. Past research has acknowledged the positive influence that transformational leaders have on employee (extra-role) performance. However, less is known about the psychological mechanisms that may explain the links between transformational leaders and extra-role performance, which encompasses behaviours that are not considered formal job requirements, but which facilitate the smooth functioning of the organization as a social system. Seventeen supervisors evaluated nurses' extra-role performance, the data generating a sample consisting of 280 dyads. The nurses worked in different health services in a large Portuguese hospital and the participation rate was 76·9% for nurses and 100% for supervisors. Data were collected during 2009. A theory-driven model of the relationships between transformation leadership, self-efficacy, work engagement and nurses' extra-role performance was tested using Structural Equation Modelling. Data analysis revealed a full mediation model in which transformational leadership explained extra-role performance through self-efficacy and work engagement. A direct relationship between transformational leadership and work engagement was also found. Nurses' supervisors with a transformational leadership style enhance different 'extra-role' performance in nurses and this increases hospital efficacy. They do so by establishing a sense of self-efficacy but also by amplifying their levels of engagement in the workplace. © 2011 Blackwell Publishing Ltd.

  11. Limitations in distance and frequency due to chromatic dispersion in fibre-optic microwave and millimeter-wave links

    DEFF Research Database (Denmark)

    Gliese, Ulrik Bo; Nielsen, Søren Nørskov

    1996-01-01

    Chromatic dispersion significantly limits the distance and/or frequency in fibre-optic microwave and millimeter-wave links based on direct detection due to a decrease of the carrier to noise ratio. The limitations in links based on coherent remote heterodyne detection, however, are far less...

  12. Wavelet transform analysis to assess oscillations in pial artery pulsation at the human cardiac frequency.

    Science.gov (United States)

    Winklewski, P J; Gruszecki, M; Wolf, J; Swierblewska, E; Kunicka, K; Wszedybyl-Winklewska, M; Guminski, W; Zabulewicz, J; Frydrychowski, A F; Bieniaszewski, L; Narkiewicz, K

    2015-05-01

    Pial artery adjustments to changes in blood pressure (BP) may last only seconds in humans. Using a novel method called near-infrared transillumination backscattering sounding (NIR-T/BSS) that allows for the non-invasive measurement of pial artery pulsation (cc-TQ) in humans, we aimed to assess the relationship between spontaneous oscillations in BP and cc-TQ at frequencies between 0.5 Hz and 5 Hz. We hypothesized that analysis of very short data segments would enable the estimation of changes in the cardiac contribution to the BP vs. cc-TQ relationship during very rapid pial artery adjustments to external stimuli. BP and pial artery oscillations during baseline (70s and 10s signals) and the response to maximal breath-hold apnea were studied in eighteen healthy subjects. The cc-TQ was measured using NIR-T/BSS; cerebral blood flow velocity, the pulsatility index and the resistive index were measured using Doppler ultrasound of the left internal carotid artery; heart rate and beat-to-beat systolic and diastolic blood pressure were recorded using a Finometer; end-tidal CO2 was measured using a medical gas analyzer. Wavelet transform analysis was used to assess the relationship between BP and cc-TQ oscillations. The recordings lasting 10s and representing 10 cycles with a frequency of ~1 Hz provided sufficient accuracy with respect to wavelet coherence and wavelet phase coherence values and yielded similar results to those obtained from approximately 70cycles (70s). A slight but significant decrease in wavelet coherence between augmented BP and cc-TQ oscillations was observed by the end of apnea. Wavelet transform analysis can be used to assess the relationship between BP and cc-TQ oscillations at cardiac frequency using signals intervals as short as 10s. Apnea slightly decreases the contribution of cardiac activity to BP and cc-TQ oscillations.

  13. Length and refractive index measurement by Fourier transform interferometry and frequency comb spectroscopy

    Science.gov (United States)

    Balling, Petr; Mašika, Pavel; Křen, Petr; Doležal, Miroslav

    2012-09-01

    In this paper we describe the progress we have made in our simultaneous length measurement and the femtosecond comb interferometric spectroscopy in a conventional arrangement with a moving mirror. Scanning and detection over an interval longer than the distance between two consecutive pulses of the frequency comb allow for a spectral resolution of the individual frequency modes of the comb. Precise knowledge of comb mode frequency leads to a precise estimation of the spectral characteristics of inspected phenomena. Using the pulse train of the frequency comb allows for measurement with highly unbalanced lengths of interferometer arms, i.e. an absolute long distance measurement. Further, we present a non-contact (double sided) method of measurement of the length/thickness of plane-parallel objects (gauge blocks, glass samples) by combining the fs comb (white light) with single frequency laser interferometry. The position of a fringe packet is evaluated by estimating the stationary phase position for any wavelength in the spectral band used. The repeatability of this position estimation is a few nanometres regardless of whether dispersion of the arms is compensated (transform limited fringe packet ˜10 fringes FWHM) or highly different (fringe packet stretched to >200 fringes FWHM). The measurement of steel gauge block by this method was compared with the standard method, and deviation (+13 ± 12) nm for gauge blocks (2 to 100) mm was found. The measurement of low reflecting ceramic gauges or clear glass samples was also tested. In the case of glass, it becomes possible to measure simultaneously both the thickness and the refractive index (and dispersion) of flat samples.

  14. Novel high-frequency, high-power, pulsed oscillator based on a transmission line transformer.

    Science.gov (United States)

    Burdt, R; Curry, R D

    2007-07-01

    Recent analysis and experiments have demonstrated the potential for transmission line transformers to be employed as compact, high-frequency, high-power, pulsed oscillators with variable rise time, high output impedance, and high operating efficiency. A prototype system was fabricated and tested that generates a damped sinusoidal wave form at a center frequency of 4 MHz into a 200 Omega load, with operating efficiency above 90% and peak power on the order of 10 MW. The initial rise time of the pulse is variable and two experiments were conducted to demonstrate initial rise times of 12 and 3 ns, corresponding to a spectral content from 4-30 and from 4-100 MHz, respectively. A SPICE model has been developed to accurately predict the circuit behavior and scaling laws have been identified to allow for circuit design at higher frequencies and higher peak power. The applications, circuit analysis, test stand, experimental results, circuit modeling, and design of future systems are all discussed.

  15. Effect of soil temperature on one-way optical frequency transfer through dense-wavelength-division-multiplexing fibre links

    CERN Document Server

    Pinkert, T J; Jansen, G S M; Dijck, E A; Groeneveld, B G H M; Smets, R; Bosveld, F C; Ubachs, W; Jungmann, K; Eikema, K S E; Koelemeij, J C J

    2014-01-01

    Results of optical frequency transfer over a carrier-grade dense-wavelength-division-multiplexing (DWDM) optical fibre network are presented. The relation between soil temperature changes on a buried optical fibre and frequency changes of an optical carrier through the fibre is modelled. Soil temperatures, measured at various depths by the Royal Netherlands Meteorology Institute (KNMI) are compared with observed frequency variations through this model. A comparison of a nine-day record of optical frequency measurements through the 2 x 298 km fibre link with soil temperature data shows qualitative agreement. A soil temperature model is used to predict the link stability over longer periods (days-months-years). We show that one-way optical frequency dissemination is sufficiently stable to distribute and compare e.g. rubidium frequency standards over standard DWDM optical fibre networks.

  16. Effect of soil temperature on optical frequency transfer through unidirectional dense-wavelength-division-multiplexing fiber-optic links.

    Science.gov (United States)

    Pinkert, T J; Böll, O; Willmann, L; Jansen, G S M; Dijck, E A; Groeneveld, B G H M; Smets, R; Bosveld, F C; Ubachs, W; Jungmann, K; Eikema, K S E; Koelemeij, J C J

    2015-02-01

    Results of optical frequency transfer over a carrier-grade dense-wavelength-division-multiplexing (DWDM) optical fiber network are presented. The relation between soil temperature changes on a buried optical fiber and frequency changes of an optical carrier through the fiber is modeled. Soil temperatures, measured at various depths by the Royal Netherlands Meteorology Institute (KNMI) are compared with observed frequency variations through this model. A comparison of a nine-day record of optical frequency measurements through the 2×298  km fiber link with soil temperature data shows qualitative agreement. A soil temperature model is used to predict the link stability over longer periods (days-months-years). We show that optical frequency dissemination is sufficiently stable to distribute and compare, e.g., rubidium frequency standards over standard DWDM optical fiber networks using unidirectional fibers.

  17. The space-math link in preschool boys and girls: Importance of mental transformation, targeting accuracy, and spatial anxiety.

    Science.gov (United States)

    Wong, Wang I

    2017-06-01

    Spatial abilities are pertinent to mathematical competence, but evidence of the space-math link has largely been confined to older samples and intrinsic spatial abilities (e.g., mental transformation). The roles of gender and affective factors are also unclear. This study examined the correlations between counting ability, mental transformation, and targeting accuracy in 182 Hong Kong preschoolers, and whether these relationships were weaker at higher spatial anxiety levels. Both spatial abilities related with counting similarly for boys and girls. Targeting accuracy also mediated the male advantage in counting. Interestingly, spatial anxiety moderated the space-math links, but differently for boys and girls. For boys, spatial abilities were irrelevant to counting at high anxiety levels; for girls, the role of anxiety on the space-math link is less clear. Results extend the evidence base of the space-math link to include an extrinsic spatial ability (targeting accuracy) and have implications for intervention programmes. Statement of contribution What is already known on this subject? Much evidence of a space-math link in adolescent and adult samples and for intrinsic spatial abilities. What does this study add? Extended the space-math link to include both intrinsic and extrinsic spatial abilities in a preschool sample. Showed how spatial anxiety moderated the space-math link differently for boys and girls. © 2016 The British Psychological Society.

  18. Distributed Secondary Voltage and Frequency Control for Islanded Microgrids with Uncertain Communication Links

    DEFF Research Database (Denmark)

    Lu, Xiaoqing; Yu, Xinghuo; Lai, Jingang

    2017-01-01

    This paper presents a robust distributed secondary control (DSC) scheme for inverter-based microgrids (MGs) in a distribution sparse network with uncertain communication links. By using the iterative learning mechanics, two discrete-time DSC controllers are designed, which enable all distributed...... energy resources (DERs) in a MG to achieve the voltage/frequency restoration and active power sharing accuracy, respectively. In special, the secondary control inputs are merely updated at the end of each round of iteration, and thus each DER only needs to share information with its neighbors...... intermittently in a low-bandwidth communication manner. This way, the communication costs are greatly reduced, and some sufficient conditions on the system stability and robustness to the uncertainties are also derived by using the tools of Lyapunov stability theory, algebraic graph theory, and matrix inequality...

  19. Extremely low-frequency electromagnetic fields affect lipid-linked carbonic anhydrase.

    Science.gov (United States)

    Ravera, Silvia; Pepe, Isidoro Mario; Calzia, Daniela; Morelli, Alessandro; Panfoli, Isabella

    2011-06-01

    In the last years, the effect of extremely low-frequency electromagnetic fields (ELF-EMF) on the activity of different enzymes were investigated. Only the membrane-anchored enzymes did decrease their activity, up to 50%. In this work, the effect of ELF-EMF on bovine lung membrane carbonic anhydrase (CA) were studied. Carbonic anhydrases are a family of 14 zinc-containing isozymes catalyzing the reversible reaction: CO(2)+H(2)O = HCO(3)(- )+H(+). CA differ in catalytic activity and subcellular localization. CA IV, IX, XII, XIV, and XV are membrane bound. In particular, CA IV, which is expressed in the lung, is glycosyl phosphatidyl inositol-linked to the membrane, therefore it was a candidate to inhibition by ELF-EMF. Exposure to the membranes to a field of 75 Hz frequency and different amplitudes caused CA activity to a reproducible decrease in enzymatic activity by 17% with a threshold of about 0.74 mT. The decrease in enzymatic activity was independent of the time of permanence in the field and was completely reversible. When the source of enzyme was solubilized with Triton, the field lost its effect on CA enzymatic activity, suggesting a crucial role of the membrane, as well as of the particular linkage of the enzyme to it, in determining the conditions for CA inactivation. Results are discussed in terms of the possible physiologic effects of CA inhibition in target organs.

  20. Carrier phase recovery performance for PN-spread TDRSS link with radio-frequency interference

    Science.gov (United States)

    Mckenzie, T. M.; Braun, W. R.

    1979-01-01

    The carrier-phase recovery performance of a Costas loop for a nonlinear satellite channel with uplink and downlink noise is analyzed, and the extension of these results to the case where uplink radio-frequency interference (RFI) is present is considered. The signal format here is binary phase-shift-keyed (BPSK) or unbalanced quaternary phase-shift-keyed (UQPSK), the signals being either the non-return-to-zero (NRZ) or biphase (Manchester) type. With UQPSK, at least one data stream must be PN-spread. The channel comprises additive white Gaussian noise (WGN), a wideband filter, a bandpass nonlinearity and more additive WGN. The RFI being considered is pulsed continuous-wave, pulsed WGN, or a combination of the two. It is noted that the Tracking and Data Relay Satellite System (TDRSS) will be subjected to RFI from certain locations, especially in the S-band of frequencies. The characteristics of this link are generalized to form the assumptions underlying this analysis. The analytical results given include the S-curve of the equivalent loop and the phase-error variance of the linearized loop.

  1. Obesity-linked homologues TfAP-2 and Twz establish meal frequency in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Michael J Williams

    2014-09-01

    Full Text Available In all animals managing the size of individual meals and frequency of feeding is crucial for metabolic homeostasis. In the current study we demonstrate that the noradrenalin analogue octopamine and the cholecystokinin (CCK homologue Drosulfakinin (Dsk function downstream of TfAP-2 and Tiwaz (Twz to control the number of meals in adult flies. Loss of TfAP-2 or Twz in octopaminergic neurons increased the size of individual meals, while overexpression of TfAP-2 significantly decreased meal size and increased feeding frequency. Of note, our study reveals that TfAP-2 and Twz regulate octopamine signaling to initiate feeding; then octopamine, in a negative feedback loop, induces expression of Dsk to inhibit consummatory behavior. Intriguingly, we found that the mouse TfAP-2 and Twz homologues, AP-2β and Kctd15, co-localize in areas of the brain known to regulate feeding behavior and reward, and a proximity ligation assay (PLA demonstrated that AP-2β and Kctd15 interact directly in a mouse hypothalamus-derived cell line. Finally, we show that in this mouse hypothalamic cell line AP-2β and Kctd15 directly interact with Ube2i, a mouse sumoylation enzyme, and that AP-2β may itself be sumoylated. Our study reveals how two obesity-linked homologues regulate metabolic homeostasis by modulating consummatory behavior.

  2. STATE TRANSFORMATION PROCESSES FOR FREE-FLOATING THREE-LINK PLANAR ROBOTS

    Institute of Scientific and Technical Information of China (English)

    Xu Mingtao; Xu Yangsheng; James K. Mills

    2004-01-01

    The transformation process of an m-DOF free-floating robot from one static state to a different static state has m degrees of freedom.The proposed approach of these transformations util-izes a series of single-DOF transformation processes as an alternative to the m-DOF transformation process.Two static state transformation processes are studied in detail.First,a single-DOF transformation process is established using a newly defined concept,referred to as transformation planning,and the definite integral of conservation of angular momentum.Second,the governing equation of the single-DOF transformation process is established using the dynamic equations of motion of the robot.This allows the joint torques to be computed to effect the state transformation.Finally,an extension of the single-DOF transformation process is proposed to extend the application of this proposed transformation methodology to create a transformation net which allows the reconfiguration of a robot from one state to many other possible states.

  3. The linear variable differential transformer (LVDT) position sensor for gravitational wave interferometer low-frequency controls

    CERN Document Server

    Tariq, H; Vetrano, F; Wang Chen Yang; Bertolini, A; Calamai, G; DeSalvo, R; Gennai, A; Holloway, L E; Losurdo, G; Marka, S; Mazzoni, M; Paoletti, F; Passuello, D; Sannibale, V; Stanga, R

    2002-01-01

    Low-power, ultra-high-vacuum compatible, non-contacting position sensors with nanometer resolution and centimeter dynamic range have been developed, built and tested. They have been designed at Virgo as the sensors for low-frequency modal damping of Seismic Attenuation System chains in Gravitational Wave interferometers and sub-micron absolute mirror positioning. One type of these linear variable differential transformers (LVDTs) has been designed to be also insensitive to transversal displacement thus allowing 3D movement of the sensor head while still precisely reading its position along the sensitivity axis. A second LVDT geometry has been designed to measure the displacement of the vertical seismic attenuation filters from their nominal position. Unlike the commercial LVDTs, mostly based on magnetic cores, the LVDTs described here exert no force on the measured structure.

  4. Time-Frequency Signal Processing Based on Fractional Fourier Transform in Passive Sonar Classification

    Directory of Open Access Journals (Sweden)

    Vahid Bagheri

    2014-11-01

    Full Text Available This paper introduce a new data SONAR classification method based on Short-Time Fractional Fourier Transform (STFrFT analysis. The passive SONAR system receives the acoustic signals radiated by vessels and attempts to categorize them as a function of the similarities between vessels of the same class.Here, a time-frequency processing and feature extraction method is developed in order to improve the performance of a feedforwardneural network, which is used to classify five classes of vessels.Processing of time-varying signals in fractional fourier domain allows us to estimate the signal with higher concentration than conventional fourier domain, making the technique robust against additive noise, maintaining same computational complexity. With the purpose of dimension reduction and classification improvement, we use Linear Discriminant Analysis (LDA technique. The feasibility of the proposed technique (STFrFTLDA has been tested experimentally using a real database. The experimental results show the superiority of the proposed method

  5. Extremely low-frequency magnetic fields of transformers and possible biological and health effects.

    Science.gov (United States)

    Sirav, Bahriye; Sezgin, Gaye; Seyhan, Nesrin

    2014-12-01

    Physiological processes in organisms can be influenced by extremely low-frequency (ELF) electromagnetic energy. Biological effect studies have great importance; as well as measurement studies since they provide information on the real exposure situations. In this study, the leakage magnetic fields around a transformer were measured in an apartment building in Küçükçekmece, Istanbul, and the measurement results were evaluated with respect to the international exposure standards. The transformer station was on the bottom floor of a three-floor building. It was found that people living and working in the building were exposed to ELF magnetic fields higher than the threshold magnetic field value of the International Agency for Research on Cancer (IARC). Many people living in this building reported health complaints such as immunological problems of their children. There were child-workers working in the textile factories located in the building. Safe distances or areas for these people should be recommended. Protective measures could be implemented to minimize these exposures. Further residential exposure studies are needed to demonstrate the exposure levels of ELF magnetic fields. Precautions should, therefore, be taken either to reduce leakage or minimize the exposed fields. Shielding techniques should be used to minimize the leakage magnetic fields in such cases.

  6. Experiences with non-intrusive monitoring of distribution transformers based on the on-line frequency response

    Directory of Open Access Journals (Sweden)

    E. Gomez Luna

    2015-04-01

    Full Text Available The following article presents the results obtained in experiences that use the Impulse Frequency Response Analysis (IFRA method with a transformer in service. The IFRA method has been implemented in order to transform the transient signals to the frequency domain using Discrete Fourier Transform (DFT. However, it can be considered that the DFT is not the most suitable tool for this type of analysis, since, by definition, this tool is useful for processing stationary signals. Taking that into consideration, the analysis of transient signals could be hypothetically improved by using continuous wavelet transform (CWT, given their variable time/frequency resolution. The analysis of transient signals in Wavelet domain has improved the repeatability of the frequency response curves, as it has been observed in experimental results. The proposed on-line IFRA method, based on Wavelet transform, was validated under load and no-load conditions on a 150 kVA three-phase transformer 13200/225 Volts, in the Campus of the Universidad del Valle, Cali, Colombia.

  7. Testing the associative-link hypothesis in immediate serial recall: Evidence from word frequency and word imageability effects.

    Science.gov (United States)

    Tse, Chi-Shing; Altarriba, Jeanette

    2007-08-01

    Two immediate serial recall experiments were conducted to test the associative-link hypothesis (Stuart & Hulme, 2000). We manipulated interitem association by varying the intralist latent semantic analysis (LSA) cosines in our 7-item study word lists, each of which consists of high- or low-frequency words in Experiment 1 and high- or low-imageability words in Experiment 2. Whether item recall performance was scored by a serial-recall or free-recall criterion, we found main effects of interitem association, word imageability, and word frequency. The effect of interitem association also interacted with the word frequency effect, but not with the word imageability effect. The LSA-cosinexword frequency interaction occurred in the recency, but not primacy, portion of the serial position curve. The present findings set explanatory boundaries for the associative-link hypothesis and we argue that both item- and associative-based mechanisms are necessary to account for the word frequency effect in immediate serial recall.

  8. Word frequency effects in immediate serial recall of pure and mixed lists: tests of the associative link hypothesis.

    Science.gov (United States)

    Saint-Aubin, Jean; LeBlanc, Jacinthe

    2005-12-01

    In immediate serial recall, high-frequency words are better recalled than low-frequency words. Recently, it has been suggested that high-frequency words are better recalled because of their better long-term associative links, and not because of the intrinsic properties of their long-term representations. In the experiment reported here, recall performance was compared for pure lists of high- and low-frequency words, and for mixed lists composed of either one low- and five high-frequency words or the reverse. The usual advantage of high-frequency words was found with pure lists and this advantage was reduced, but still significant with mixed lists composed of five low-frequency words. However, the low-frequency word included in a high-frequency list was recalled just as well as high-frequency words. Results are challenging for the associative link hypothesis and are best interpreted within an item-based reconstruction hypothesis, along with a distinctiveness account.

  9. ZVZCS Based High Frequency Link Grid Connected SVM applied Three Phase Three Level Diode Clamped Inverter for Photovoltaic Applications Part-II

    Directory of Open Access Journals (Sweden)

    Soumyadeep Ray

    2014-07-01

    Full Text Available This article proposes a newly proposed highly effective Zero Voltage and Zero Current switching based Front end converter with a High Frequency Transformer with a Three Phase Three Level Diode Clamped Inverter in photovoltaic applications. The switching scheme is implemented in MATLAB/ Simulink condition. ZVZCS condition is achieved. This type of converter shows high efficiency and very negligible switching loss. Finally ZVZCS based High Frequency Link Diode Clamped Inverter is connected to Grid. An MCI optimized Current controller is used with SVM switching technique.  In This article, responses with three types of controllers (I, PI, PID have been examined and compared. Simulation results show the effectiveness, and validity of this technique.

  10. Serial CT and MRI of ischaemic cerebral infarcts: frequency and clinical impact of haemorrhagic transformation

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, T.E.; Brueckmann, H. [Muenchen Univ. (Germany). Abt. fuer Neuroradiologie; Schulte-Altedorneburg, G. [Dept. of Radiology/Neuroradiology, University Medical School of Luebeck (Germany); Droste, D.W. [Dept. of Neurology, University Medical School of Luebeck (Germany)

    2000-04-01

    The frequency, predisposing factors and clinical consequences of haemorrhagic infarcts and damaged blood-brain barrier as shown by contrast enhancement (CE) in ischaemic cerebral infarcts are controversial. We prospectively compared the sensitivity of CT and MRI to haemorrhagic transformation (HT) and CE. We also wished to investigate the clinical significance of HT and factors possibly associated with it. We studied 36 patients with acute ischaemic infarcts in the middle cerebral artery territory during the first 2 weeks after the ictus. After CT and rating of the neurological deficit on admission, serial examinations with clinical neuromonitoring, contrast-enhanced CT and MRI were done on the same day. The occurrence and severity of HT were correlated with CE, stroke mechanism, infarct size, development of neurological deficits and antithrombotic treatment. The frequency of HT detected by MRI was 80 %. CE usually preceded HT or was seen simultaneously. MRI had a higher sensitivity than CT to HT and CE. Severity of HT was positively correlated with infarct size (P < 0.01). HT had no influence on patient's neurological status. Neither the type of antithrombotic treatment nor the stroke mechanism was associated with the severity of HT. No parenchymal haemorrhage occurred. (orig.)

  11. Dispersion compensation in Lamb wave defect detection with step-pulse excitation and warped frequency transform.

    Science.gov (United States)

    Fu, Shangchen; Shi, Lihua; Zhou, Yinghui; Cai, Jian

    2014-12-01

    The damage localization accuracy of a Lamb wave detection method is greatly influenced by the multi-mode character and the dispersion effect of Lamb waves. Warped frequency transform (WFT) with a warping function derived from the frequency-dependent phase velocity can be used to suppress the dispersion. Step-pulse excitation is adopted in this paper and the transfer function of the propagation path is extracted from the step-pulse response. WFT is then used to compensate the transfer function, and the compensation of the narrowband signal is realized by convolution of the ideal narrowband burst signal with the compensated transfer function. Considering that wavenumber is a key parameter in designing the warping function for compensation, we presented a method in this paper to calculate the wavenumber directly from the measured signal. This method uses the phase response to estimate the curve of wavenumber. The WFT method is then combined with the delay-and-sum Lamb wave imaging method to improve the imaging resolution. A comparison with traditional delay-and-sum method and time-reversal method verifies the effect of this method in improving the damage localization results. It is shown that the proposed method leverages dispersion to enable good performance in the presence of multiple modes.

  12. Superconducting multiturn flux transformers for radio frequency superconducting quantum interference devices

    Science.gov (United States)

    Yi, H. R.; Zhang, Y.; Schubert, J.; Zander, W.; Zeng, X. H.; Klein, N.

    2000-11-01

    This article describes three planar layouts of superconducting multiturn flux transformers integrated with a coplanar resonator for radio frequency (rf) superconducting quantum interference device (SQUID) magnetometers. The best magnetic field noise values of 22 and 11.5 fT/Hz1/2 in the white noise regime were obtained for the layout with two input coils and the layout with the labyrinth resonator, respectively. Excess low-frequency noise (about 200 fT/Hz1/2 at 10 Hz) was present. Computer simulation showed that the loss in this trilayer system was dominated by the high loss tangent of the dielectric film used for the separation of the upper and lower superconducting films. The rf coupling coefficient krf between the resonator and the flip-chip-coupled SQUID was also estimated. The values krf2≈14×10-3 obtained for the layout with two input coils, and krf2≈45×10-3 for the layout with the labyrinth resonator were considerably higher than the typical value of krf2≈7×10-3 for the single-layer coplanar resonator. These high coupling coefficients have compensated the somewhat degraded unloaded quality factor of the resonator, thus securing the optimum operation of the rf SQUID.

  13. Time-frequency analysis of non-stationary fusion plasma signals using an improved Hilbert-Huang transform

    Science.gov (United States)

    Liu, Yangqing; Tan, Yi; Xie, Huiqiao; Wang, Wenhao; Gao, Zhe

    2014-07-01

    An improved Hilbert-Huang transform method is developed to the time-frequency analysis of non-stationary signals in tokamak plasmas. Maximal overlap discrete wavelet packet transform rather than wavelet packet transform is proposed as a preprocessor to decompose a signal into various narrow-band components. Then, a correlation coefficient based selection method is utilized to eliminate the irrelevant intrinsic mode functions obtained from empirical mode decomposition of those narrow-band components. Subsequently, a time varying vector autoregressive moving average model instead of Hilbert spectral analysis is performed to compute the Hilbert spectrum, i.e., a three-dimensional time-frequency distribution of the signal. The feasibility and effectiveness of the improved Hilbert-Huang transform method is demonstrated by analyzing a non-stationary simulated signal and actual experimental signals in fusion plasmas.

  14. Time-frequency analysis of non-stationary fusion plasma signals using an improved Hilbert-Huang transform

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yangqing, E-mail: liuyq05@gmail.com; Tan, Yi; Xie, Huiqiao; Wang, Wenhao; Gao, Zhe [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China)

    2014-07-15

    An improved Hilbert-Huang transform method is developed to the time-frequency analysis of non-stationary signals in tokamak plasmas. Maximal overlap discrete wavelet packet transform rather than wavelet packet transform is proposed as a preprocessor to decompose a signal into various narrow-band components. Then, a correlation coefficient based selection method is utilized to eliminate the irrelevant intrinsic mode functions obtained from empirical mode decomposition of those narrow-band components. Subsequently, a time varying vector autoregressive moving average model instead of Hilbert spectral analysis is performed to compute the Hilbert spectrum, i.e., a three-dimensional time-frequency distribution of the signal. The feasibility and effectiveness of the improved Hilbert-Huang transform method is demonstrated by analyzing a non-stationary simulated signal and actual experimental signals in fusion plasmas.

  15. Linking high-frequency DOC dynamics to the age of connected water sources

    Science.gov (United States)

    Tunaley, C.; Tetzlaff, D.; Lessels, J.; Soulsby, C.

    2016-07-01

    We combined high-frequency dissolved organic matter fluorescence (FDOM) data with stable isotope observations to identify the sources and ages of runoff that cause temporal variability in dissolved organic carbon (DOC) within a peat-dominated Scottish catchment. FDOM was strongly correlated (r2 ˜ 0.8) with DOC, allowing inference of a 15 min time series. We captured 34 events over a range of hydrological conditions. Along with marked seasonality, different event responses were observed during summer depending on dry or wet antecedent conditions. The majority of events exhibited anticlockwise hysteresis as a result of the expansion of the riparian saturation zone, mobilizing previously unconnected DOC sources. Water ages from the main runoff sources were extracted from a tracer-aided hydrological model. Particularly useful were ages of overland flow, which were negatively correlated with DOC concentration. Overland flow age, which ranged between 0.2 and 360 days, reflected antecedent conditions, with younger water generally mobilizing the highest DOC concentrations in summer events. During small events with dry antecedent conditions, DOC response was proportionally higher due to the displacement and mixing of small volumes of previously unconnected highly concentrated riparian soil waters by new precipitation. During large events with wet antecedent conditions, the riparian saturation zone expands to organic layers on the hillslopes causing peaks in DOC. However, these peaks were limited by dilution and supply. This study highlights the utility of linking high-frequency DOC measurements with other tracers, allowing the effects of hydrologic connectivity and antecedent conditions on delivery of DOC to streams to be assessed.

  16. Transformer modeling for low- and mid-frequency electromagnetic transients simulation

    Science.gov (United States)

    Lambert, Mathieu

    In this work, new models are developed for single-phase and three-phase shell-type transformers for the simulation of low-frequency transients, with the use of the coupled leakage model. This approach has the advantage that it avoids the use of fictitious windings to connect the leakage model to a topological core model, while giving the same response in short-circuit as the indefinite admittance matrix (BCTRAN) model. To further increase the model sophistication, it is proposed to divide windings into coils in the new models. However, short-circuit measurements between coils are never available. Therefore, a novel analytical method is elaborated for this purpose, which allows the calculation in 2-D of short-circuit inductances between coils of rectangular cross-section. The results of this new method are in agreement with the results obtained from the finite element method in 2-D. Furthermore, the assumption that the leakage field is approximately 2-D in shell-type transformers is validated with a 3-D simulation. The outcome of this method is used to calculate the self and mutual inductances between the coils of the coupled leakage model and the results are showing good correspondence with terminal short-circuit measurements. Typically, leakage inductances in transformers are calculated from short-circuit measurements and the magnetizing branch is calculated from no-load measurements, assuming that leakages are unimportant for the unloaded transformer and that magnetizing current is negligible during a short-circuit. While the core is assumed to have an infinite permeability to calculate short-circuit inductances, and it is a reasonable assumption since the core's magnetomotive force is negligible during a short-circuit, the same reasoning does not necessarily hold true for leakage fluxes in no-load conditions. This is because the core starts to saturate when the transformer is unloaded. To take this into account, a new analytical method is developed in this

  17. Transforming Growth Factor-β1 T869C Gene Polymorphism Is Associated with Acquired Sick Sinus Syndrome via Linking a Higher Serum Protein Level.

    Directory of Open Access Journals (Sweden)

    Jan-Yow Chen

    Full Text Available Familial sick sinus syndrome is associated with gene mutations and dysfunction of ion channels. In contrast, degenerative fibrosis of the sinus node tissue plays an important role in the pathogenesis of acquired sick sinus syndrome. There is a close relationship between transforming growth factor-β1 mediated cardiac fibrosis and acquired arrhythmia. It is of interest to examine whether transforming growth factor-β1 is involved in the pathogenesis of acquired sick sinus syndrome.Overall, 110 patients with acquired SSS and 137 age/gender-matched controls were screened for transforming growth factor-β1 and cardiac sodium channel gene polymorphisms using gene sequencing or restriction fragment length polymorphism methods. An enzyme-linked immunosorbent assay was used to determine the serum level of transforming growth factor-β1.Two transforming growth factor-β1 gene polymorphisms (C-509T and T+869C and one cardiac sodium channel gene polymorphism (H588R have been identified. The C-dominant CC/CT genotype frequency of T869C was significantly higher in acquired sick sinus syndrome patients than in controls (OR 2.09, 95% CI 1.16-3.75, P = 0.01. Consistently, the level of serum transforming growth factor-β1 was also significantly greater in acquired sick sinus syndrome group than in controls (5.3±3.4 ng/ml vs. 3.7±2.4 ng/ml, P = 0.01. In addition, the CC/CT genotypes showed a higher transforming growth factor-β1 serum level than the TT genotype (4.25 ± 2.50 ng/ml vs. 2.71± 1.76 ng/ml, P = 0.028 in controls.Transforming growth factor-β1 T869C polymorphism, correlated with high serum transforming growth factor-β1 levels, is associated with susceptibility to acquired sick sinus syndrome.

  18. Restoration of Normal Frequency Affected by Small Load Variations Through HVDC link Using Neuro-Fuzzy Approach

    OpenAIRE

    Anil Kumar Sharma,; Dr. G. K. Joshi,; Tarun Kumar De; Shyam Krishan Joshi

    2011-01-01

    HVDC power transmission is coming up with merits to replace the EHV-AC system. The controller inverter operation can successfully regulate the power in HVDC link leading to fulfillment ofpower demand in A.C. networks caused by sudden rise in loading. Since overloading and unloading both lead to the departure of operating frequency below or above normal, its control for normalization isexercised through control of power flow in HVDC Link. Also the same is achieved by adjusting firing delay ang...

  19. Planar-waveguide external cavity laser stabilization for an optical link with 10(-19) frequency stability.

    Science.gov (United States)

    Clivati, Cecilia; Mura, Alberto; Calonico, Davide; Levi, Filippo; Costanzo, Giovanni A; Calosso, Claudio E; Godone, Aldo

    2011-12-01

    We stabilized the frequency of a compact planar-waveguide external cavity laser (ECL) on a Fabry-Perot cavity (FPC) through a Pound-Drever-Hall scheme. The residual frequency stability of the ECL is 10(-14), comparable to the stability achievable with a fiber laser (FL) locked to an FPC through the same scheme. We set up an optical link of 100 km, based on fiber spools, that reaches 10(-19) relative stability, and we show that its performances using the ECL or FL are comparable. Thus ECLs could serve as an excellent replacement for FLs in optical links where cost-effectiveness and robustness are important considerations.

  20. Perceptual Coding of Audio Signals Using Adaptive Time-Frequency Transform

    Directory of Open Access Journals (Sweden)

    Karthikeyan Umapathy

    2007-08-01

    Full Text Available Wide band digital audio signals have a very high data-rate associated with them due to their complex nature and demand for high-quality reproduction. Although recent technological advancements have significantly reduced the cost of bandwidth and miniaturized storage facilities, the rapid increase in the volume of digital audio content constantly compels the need for better compression algorithms. Over the years various perceptually lossless compression techniques have been introduced, and transform-based compression techniques have made a significant impact in recent years. In this paper, we propose one such transform-based compression technique, where the joint time-frequency (TF properties of the nonstationary nature of the audio signals were exploited in creating a compact energy representation of the signal in fewer coefficients. The decomposition coefficients were processed and perceptually filtered to retain only the relevant coefficients. Perceptual filtering (psychoacoustics was applied in a novel way by analyzing and performing TF specific psychoacoustics experiments. An added advantage of the proposed technique is that, due to its signal adaptive nature, it does not need predetermined segmentation of audio signals for processing. Eight stereo audio signal samples of different varieties were used in the study. Subjective (mean opinion score—MOS listening tests were performed and the subjective difference grades (SDG were used to compare the performance of the proposed coder with MP3, AAC, and HE-AAC encoders. Compression ratios in the range of 8 to 40 were achieved by the proposed technique with subjective difference grades (SDG ranging from –0.53 to –2.27.

  1. Perceptual Coding of Audio Signals Using Adaptive Time-Frequency Transform

    Directory of Open Access Journals (Sweden)

    Umapathy Karthikeyan

    2007-01-01

    Full Text Available Wide band digital audio signals have a very high data-rate associated with them due to their complex nature and demand for high-quality reproduction. Although recent technological advancements have significantly reduced the cost of bandwidth and miniaturized storage facilities, the rapid increase in the volume of digital audio content constantly compels the need for better compression algorithms. Over the years various perceptually lossless compression techniques have been introduced, and transform-based compression techniques have made a significant impact in recent years. In this paper, we propose one such transform-based compression technique, where the joint time-frequency (TF properties of the nonstationary nature of the audio signals were exploited in creating a compact energy representation of the signal in fewer coefficients. The decomposition coefficients were processed and perceptually filtered to retain only the relevant coefficients. Perceptual filtering (psychoacoustics was applied in a novel way by analyzing and performing TF specific psychoacoustics experiments. An added advantage of the proposed technique is that, due to its signal adaptive nature, it does not need predetermined segmentation of audio signals for processing. Eight stereo audio signal samples of different varieties were used in the study. Subjective (mean opinion score—MOS listening tests were performed and the subjective difference grades (SDG were used to compare the performance of the proposed coder with MP3, AAC, and HE-AAC encoders. Compression ratios in the range of 8 to 40 were achieved by the proposed technique with subjective difference grades (SDG ranging from –0.53 to –2.27.

  2. A joint synchronization parameter estimation in fractional Fourier transform orthogonal frequency division multiplexing underwater acoustic communication system

    Directory of Open Access Journals (Sweden)

    Jia-chun Zheng

    2016-03-01

    Full Text Available In the conditions of Gaussian noise, symmetric alpha stable impulse noise, multipath propagation, Doppler effect, and so on, a joint synchronization algorithm is proposed for underwater acoustic communication system based on fractional Fourier transform orthogonal frequency division multiplexing. The algorithm realizes the orthogonal multicarrier underwater acoustic communication system synchronization based on that the symmetrical triangular linear frequency modulation signal has the energy convergence in the domain of fractional Fourier transform. In order to verify the effectiveness of the algorithm, hyperbolic frequency modulation signal and linear frequency modulation signal are used as the evaluation index, and the synchronization performance of bit error rate of them is compared by simulation and pool experiments. The simulation results show that the proposed algorithm in this article is resistant to Gaussian noise, symmetric alpha stable pulse noise, multipath propagation, and Doppler effect, compared with traditional synchronization algorithms; the synchronization error probability is low at the same signal-to-noise ratio.

  3. HTLV-1 tax stabilizes MCL-1 via TRAF6-dependent K63-linked polyubiquitination to promote cell survival and transformation.

    Science.gov (United States)

    Choi, Young Bong; Harhaj, Edward William

    2014-10-01

    The human T-cell leukemia virus type 1 (HTLV-1) Tax protein hijacks the host ubiquitin machinery to activate IκB kinases (IKKs) and NF-κB and promote cell survival; however, the key ubiquitinated factors downstream of Tax involved in cell transformation are unknown. Using mass spectrometry, we undertook an unbiased proteome-wide quantitative survey of cellular proteins modified by ubiquitin in the presence of Tax or a Tax mutant impaired in IKK activation. Tax induced the ubiquitination of 22 cellular proteins, including the anti-apoptotic BCL-2 family member MCL-1, in an IKK-dependent manner. Tax was found to promote the nondegradative lysine 63 (K63)-linked polyubiquitination of MCL-1 that was dependent on the E3 ubiquitin ligase TRAF6 and the IKK complex. Tax interacted with and activated TRAF6, and triggered its mitochondrial localization, where it conjugated four carboxyl-terminal lysine residues of MCL-1 with K63-linked polyubiquitin chains, which stabilized and protected MCL-1 from genotoxic stress-induced degradation. TRAF6 and MCL-1 played essential roles in the survival of HTLV-1 transformed cells and the immortalization of primary T cells by HTLV-1. Therefore, K63-linked polyubiquitination represents a novel regulatory mechanism controlling MCL-1 stability that has been usurped by a viral oncogene to precipitate cell survival and transformation.

  4. The Time-Frequency Energy Attenuation Factor and Its Application on the Basis of Gauss Linear Frequency-Modulated Continuous Wavelet Transform

    Institute of Scientific and Technical Information of China (English)

    Liu Xiqiang; Shen Ping; Li Hong; Shan Changlun; Ji Aidong; Zhang Ping; Cai Mingjun

    2004-01-01

    Based on the Gauss linear frequency-modulated wavelet transform, a new characteristic index is presented, namely time-frequency energy attenuation factor which can reflect the difference features of waveform in earthquake focus mechanism, wave traveling path and its attenuation characteristics in focal area or near field. In order to test its validity, we select the natural earthquakes and explosion or collapse events whose focus mechanisms vary obviously, and some natural earthquakes located at the same site or in a very small area. The study indicates that the time-frequency energy attenuation factors of the natural earthquakes are obviously different with that of explosion or collapse events, and the change of the time-frequency energy attenuation factors is relatively stable for the earthquakes under the normal seismicity background. Using the above-mentioned method, it is expected to offer a useful criterion for strong earthquake prediction by continuous earthquake observation.

  5. Linking Transformational Materials and Processing for an Energy-Efficient and Low-Carbon Economy, 2010

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, Warren H. [Minerals, Metals, and Materials Society (TMS), Warrendale, PA (United States); Brindle, Ross [Nexight Group, LLC, Silver Spring, MD (United States); James, Mallory [Energetics Inc., Columbia, MD (United States); Justiniano, Mauricio [Energetics Inc., Columbia, MD (United States); Sabouni, Ridah [Energetics Inc., Columbia, MD (United States); Seader, Melanie [Energetics Inc., Columbia, MD (United States); Ruch, Jennifer [Energetics Inc., Columbia, MD (United States); Andres, Howard [Energetics Inc., Columbia, MD (United States); Zafar, Muhammad [Energetics Inc., Columbia, MD (United States)

    2010-06-01

    The Energy Materials Blue Ribbon Panel, representing experts from industry, academia, and government, identifies new materials and processing breakthroughs that could lead to transformational advances in energy efficiency, energy security, and carbon reduction.

  6. Nonstationary Interference Excision in Time-Frequency Domain Using Adaptive Hierarchical Lapped Orthogonal Transform for Direct Sequence Spread Spectrum Communications

    Directory of Open Access Journals (Sweden)

    Zhu Yi-Sheng

    2003-01-01

    Full Text Available An adaptive hierarchical lapped orthogonal transform (HLOT exciser is proposed for tracking, localizing, and rejecting the nonstationary interference in direct sequence spread spectrum (DSSS communications. The method is based on HLOT. It utilizes a fast dynamic programming algorithm to search for the best basis, which matches the interference structure best, in a library of lapped orthogonal bases. The adaptive HLOT differs from conventional block transform and the more advanced modulated lapped transform (MLT in that the former produces arbitrary time-frequency tiling, which can be adapted to the signal structure, while the latter yields fixed tilings. The time-frequency tiling of the adaptive HLOT can be time varying, so it is also able to track the variations of the signal time-frequency structure. Simulation results show that the proposed exciser brings significant performance improvement in the presence of nonstationary time-localized interference with or without instantaneous frequency (IF information compared with the existing block transform domain excisers. Also, the proposed exciser is effective in suppressing narrowband interference and combined narrowband and time-localized impulsive interference.

  7. MATHEMATICAL MODELS FOR SOME RADIO-FREQUENCY TRANSMISSION-LINE TRANSFORMERS

    Science.gov (United States)

    MATRICES(MATHEMATICS), *PHASE SHIFT CIRCUITS, *RADIOFREQUENCY, *TRANSFORMERS, *TRANSMISSION LINES, BROADBAND, DIELECTRIC PROPERTIES, ELECTRICAL IMPEDANCE, FERRITES, IMPEDANCE MATCHING , MATHEMATICAL ANALYSIS.

  8. Effects of laser frequency chirp on modal noise in short-range radio over multimode fiber links

    DEFF Research Database (Denmark)

    Visani, Davide; Tartarini, Giovanni; Petersen, Martin Nordal;

    2010-01-01

    An important effect of the frequency chirp of the optical transmitter in radio over multimode fiber links is put into evidence experimentally and modeled theoretically for the first time, to our knowledge. This effect can have an important impact in short-range connections, where, although...

  9. TRANSFORMATION

    Energy Technology Data Exchange (ETDEWEB)

    LACKS,S.A.

    2003-10-09

    Transformation, which alters the genetic makeup of an individual, is a concept that intrigues the human imagination. In Streptococcus pneumoniae such transformation was first demonstrated. Perhaps our fascination with genetics derived from our ancestors observing their own progeny, with its retention and assortment of parental traits, but such interest must have been accelerated after the dawn of agriculture. It was in pea plants that Gregor Mendel in the late 1800s examined inherited traits and found them to be determined by physical elements, or genes, passed from parents to progeny. In our day, the material basis of these genetic determinants was revealed to be DNA by the lowly bacteria, in particular, the pneumococcus. For this species, transformation by free DNA is a sexual process that enables cells to sport new combinations of genes and traits. Genetic transformation of the type found in S. pneumoniae occurs naturally in many species of bacteria (70), but, initially only a few other transformable species were found, namely, Haemophilus influenzae, Neisseria meningitides, Neisseria gonorrheae, and Bacillus subtilis (96). Natural transformation, which requires a set of genes evolved for the purpose, contrasts with artificial transformation, which is accomplished by shocking cells either electrically, as in electroporation, or by ionic and temperature shifts. Although such artificial treatments can introduce very small amounts of DNA into virtually any type of cell, the amounts introduced by natural transformation are a million-fold greater, and S. pneumoniae can take up as much as 10% of its cellular DNA content (40).

  10. Transformation

    DEFF Research Database (Denmark)

    Peters, Terri

    2011-01-01

    Artiklen diskuterer ordet "transformation" med udgangspunkt i dels hvorledes ordet bruges i arkitektfaglig terminologi og dels med fokus på ordets potentielle indhold og egnethed i samme teminologi.......Artiklen diskuterer ordet "transformation" med udgangspunkt i dels hvorledes ordet bruges i arkitektfaglig terminologi og dels med fokus på ordets potentielle indhold og egnethed i samme teminologi....

  11. Transformation

    DEFF Research Database (Denmark)

    Peters, Terri

    2011-01-01

    Artiklen diskuterer ordet "transformation" med udgangspunkt i dels hvorledes ordet bruges i arkitektfaglig terminologi og dels med fokus på ordets potentielle indhold og egnethed i samme teminologi.......Artiklen diskuterer ordet "transformation" med udgangspunkt i dels hvorledes ordet bruges i arkitektfaglig terminologi og dels med fokus på ordets potentielle indhold og egnethed i samme teminologi....

  12. Optical Fiber Link with 1E-19 frequency stability using a Planar-Waveguide External Cavity Laser Diode

    CERN Document Server

    Clivati, Cecilia; Calonico, Davide; Levi, Filippo; Costanzo, Giovanni A; Calosso, Claudio E; Godone, Aldo

    2011-01-01

    We compare the performances of a compact planar-waveguide external cavity laser (ECL) and a traditional fiber laser (FL) frequency locked to a Fabry-P\\'erot cavity and demonstrate the possibility to use such ECL in an optical link for ultra stable frequency dissemination. A relative stability of the ECL of 1E-14 is obtained and an optical link of 100 km based on fiber spools has been realized, that reaches 2E-19 relative stability, limited by the system noise floor. The performances of ECL and FL are shown to be comparable. Thus, ECLs could be a better choice than FLs in longer optical links with amplification and regenerating stations, thanks to their cost-effectiveness, robustness and small size.

  13. Design and Experimental Investigation for Improving the High Frequency Radio Communication Links between Benghazi-Libya and Sfax-Tunisia.

    Directory of Open Access Journals (Sweden)

    Mohamed Yousef Ahmed Abou-Hussein

    2014-02-01

    Full Text Available In this study, we have experimentally planned to replicate the positive results of the application of ionospheric prediction method to design and improve the high frequency (HF radio communication links between Benghazi-Libya and Sfax-Tunisia. The central radio propagation laboratory (CRPL method of ionospheric prediction of the National Bureau of Standards (NBS in U.S.A was used in the calculations of the optimal working frequencies for reliable HF radio communication links between Benghazi-Libya and Sfax-Tunisia. The results were drawn in the form of curves by using the computer. The computer was used to measure the received signal level variation of a frequency 17.500 Megahertz (MHz, which was transmitted with a power of 100 Kilowatt (KW from the Tunis Republic Broadcasting station in SFAX city, directed to the east region. The measurements were taken during daytime's for winter (December, January& February and summer (June, July & August seasons.

  14. Radio-frequency transparent demodulation for broadband hybrid wireless-optical links

    DEFF Research Database (Denmark)

    Zibar, Darko; Sambaraju, Rakesh; Alemany, Ruben

    2010-01-01

    A novel demodulation technique which is transparent to radio-frequency (RF) carrier frequency is presented and experimentally demonstrated for multigigabit wireless signals. The presented demodulation technique employs optical single-sideband filtering, coherent detection, and baseband digital si...

  15. The link between texting and motor vehicle collision frequency in the orthopaedic trauma population

    OpenAIRE

    Neil M. Issar; Kadakia, Rishin J.; James M. Tsahakis; Zachary T. Yoneda; Sethi, Manish K.; Mir, Hassan R.; Kristin Archer; Obremskey, William T.; A. Alex Jahangir

    2013-01-01

    Abstract: Background: This study will evaluate whether or not texting frequency while driving and/or texting frequency in general are associated with an increased risk of incurring a motor vehicle collision (MVC) resulting in orthopaedic trauma injuries. Methods: All patients who presented to the Vanderbilt University Medical Center Orthopaedic Trauma Clinic were administered a questionnaire to determine background information, mean phone use, texting frequency, texting frequency while drivin...

  16. TRANSFORMER

    Science.gov (United States)

    Baker, W.R.

    1959-08-25

    Transformers of a type adapted for use with extreme high power vacuum tubes where current requirements may be of the order of 2,000 to 200,000 amperes are described. The transformer casing has the form of a re-entrant section being extended through an opening in one end of the cylinder to form a coaxial terminal arrangement. A toroidal multi-turn primary winding is disposed within the casing in coaxial relationship therein. In a second embodiment, means are provided for forming the casing as a multi-turn secondary. The transformer is characterized by minimized resistance heating, minimized external magnetic flux, and an economical construction.

  17. Absolute frequency measurement of the 88Sr+ clock transition using a GPS link to the SI second

    Science.gov (United States)

    Dubé, Pierre; E Bernard, John; Gertsvolf, Marina

    2017-06-01

    We report the results of a recent measurement of the absolute frequency of the 5s{{ }2}{{S}1/2} - 4d{{ }2}{{D}5/2} transition of the {{}88}\\text{Sr}{{}+} ion. The optical frequency was measured against the international atomic time realization of the SI second on the geoid as obtained by frequency transfer using a global positioning system link and the precise point positioning technique. The measurement campaign yielded more than 100 h of frequency data. It was performed with improvements to the stability and accuracy of the single-ion clock compared to the last measurement made in 2012. The single ion clock uncertainty is evaluated at 1.5× {{10}-17} when contributions from acousto-optic modulator frequency chirps and servo errors are taken into account. The stability of the ion clock is 3× {{10}-15} at 1 s averaging, a factor of three better than in the previous measurement. The results from the two measurement campaigns are in good agreement. The uncertainty of the measurement, primarily from the link to the SI second, is 0.75 Hz (1.7× {{10}-15} ). The frequency measured for the S-D clock transition of {{}88}\\text{S}{{\\text{r}}+} is {ν0}= 444 779 044 095 485.27(75) Hz.

  18. Simultaneously precise frequency transfer and time synchronization using feed-forward compensation technique via 120 km fiber link.

    Science.gov (United States)

    Chen, Xing; Lu, Jinlong; Cui, Yifan; Zhang, Jian; Lu, Xing; Tian, Xusheng; Ci, Cheng; Liu, Bo; Wu, Hong; Tang, Tingsong; Shi, Kebin; Zhang, Zhigang

    2015-12-22

    Precision time synchronization between two remote sites is desired in many applications such as global positioning satellite systems, long-baseline interferometry, coherent radar detection and fundamental physics constant measurements. The recently developed frequency dissemination technologies based on optical fiber link have improved the transfer instability to the level of 10(-19)/day at remote location. Therefore it is possible to keep clock oscillation at remote locations continuously corrected, or to reproduce a "virtual" clock on the remote location. However the initial alignment and the correction of 1 pps timing signal from time to time are still required, besides the highly stabilized clock frequency transfer between distant locations. Here we demonstrate a time synchronization based on an ultra-stable frequency transfer system via 120-km commercial fiber link by transferring an optical frequency comb. Both the phase noise compensation in frequency dissemination and temporal basis alignment in time synchronization were implemented by a feed-forward digital compensation (FFDC) technique. The fractional frequency instability was measured to be 6.18 × 10(-20) at 2000 s. The timing deviation of time synchronization was measured to be 0.6 ps in 1500 s. This technique also can be applied in multi-node fiber network topology.

  19. Simultaneously precise frequency transfer and time synchronization using feed-forward compensation technique via 120 km fiber link

    Science.gov (United States)

    Chen, Xing; Lu, Jinlong; Cui, Yifan; Zhang, Jian; Lu, Xing; Tian, Xusheng; Ci, Cheng; Liu, Bo; Wu, Hong; Tang, Tingsong; Shi, Kebin; Zhang, Zhigang

    2015-12-01

    Precision time synchronization between two remote sites is desired in many applications such as global positioning satellite systems, long-baseline interferometry, coherent radar detection and fundamental physics constant measurements. The recently developed frequency dissemination technologies based on optical fiber link have improved the transfer instability to the level of 10-19/day at remote location. Therefore it is possible to keep clock oscillation at remote locations continuously corrected, or to reproduce a “virtual” clock on the remote location. However the initial alignment and the correction of 1 pps timing signal from time to time are still required, besides the highly stabilized clock frequency transfer between distant locations. Here we demonstrate a time synchronization based on an ultra-stable frequency transfer system via 120-km commercial fiber link by transferring an optical frequency comb. Both the phase noise compensation in frequency dissemination and temporal basis alignment in time synchronization were implemented by a feed-forward digital compensation (FFDC) technique. The fractional frequency instability was measured to be 6.18 × 10-20 at 2000 s. The timing deviation of time synchronization was measured to be 0.6 ps in 1500 s. This technique also can be applied in multi-node fiber network topology.

  20. Leader identity as an antecedent of the frequency and consistency of transformational, consideration, and abusive leadership behaviors.

    Science.gov (United States)

    Johnson, Russell E; Venus, Merlijn; Lanaj, Klodiana; Mao, Changguo; Chang, Chu-Hsiang

    2012-11-01

    Drawing from identity-based theories of leadership, we examined relations of leader identity with leader behavior and perceived effectiveness. To do so, we employed multiwave methodology to examine the differential impact of leaders' chronic collective, relational, and individual identities on the frequency and consistency of their subsequent transformational, consideration, and abusive behaviors over a 3-week period. We also examined the relative importance of these leadership behaviors for predicting perceived leader effectiveness as rated by subordinates and peers. Results indicated that leaders' collective and individual identities were uniquely related to transformational and abusive behaviors, respectively. We also observed a significant collective by individual identity interaction, such that abusive behaviors were most frequent when a strong individual identity was paired with a weak collective identity. Frequency of transformational behaviors accounted for the largest proportion of variance in perceived leader effectiveness, followed by frequency of abusive behaviors and consistency of transformational behaviors. We discuss the implications of these findings for leadership theory and development. (c) 2012 APA, all rights reserved.

  1. Time-frequency analysis of nonstationary vibration signals for deployable structures by using the constant-Q nonstationary gabor transform

    Science.gov (United States)

    Liu, Tao; Yan, Shaoze; Zhang, Wei

    2016-06-01

    Deployable structures have been widely used in on-orbit servicing spacecrafts, and the vibration properties of such structures have become increasingly important in the aerospace industry. The constant-Q nonstationary Gabor transform (CQ-NSGT) is introduced in this paper to accurately evaluate the variation in the frequency and amplitude of vibration signals along with time. First, an example signal is constructed on the basis of the vibration properties of deployable structures and is processed by the short-time Fourier transform, Wigner-Ville distribution, Hilbert-Huang transform, and CQ-NSGT. Results show that time and frequency resolutions are simultaneously fine only by employing CQ-NSGT. Subsequently, a zero padding operation is conducted to correct the calculation error at the end of the transform results. Finally, a set of experimental devices is constructed. The vibration signal of the experimental mode is processed by CQ-NSGT. On this basis, the experimental signal properties are discussed. This time-frequency method may be useful for formulating the dynamics for complex deployable structures.

  2. N-Linked oligosaccharide changes with oncogenic transformation require sialylation of multiantennae

    NARCIS (Netherlands)

    Vliegenthart, J.F.G.; Santer, U.V.; DeSantis, R.; Hård, K.; Kuik, J.A. van; Won, B.; Glick, M.C.

    1989-01-01

    Glycopeptides derived from NIH 3T3 fibroblasts and these cells transformed by transfection with human DNA containing oncogene H-ras were analyzed by 500-MHz 1H-NMR spectroscopy and binding to immobilized lectins. The cells were metabolically labeled with D-[3H]glucosamine or L-[3H]fucose and the gly

  3. Organizing the "Productive Transformation of Knowledge": Linking University and Industry in Traditional Manufacturing Areas

    Science.gov (United States)

    Balduzzi, Giacomo; Rostan, Michele

    2016-01-01

    The article aims at underlining the role played by extra-academic and autonomous organizations strongly connected with university institutions and researchers in producing, acquiring, transferring and transforming knowledge. The study examines a particular Italian case, the "Politecnico Calzaturiero", a private institution providing…

  4. Testing Time and Frequency Fiber-Optic Link Transfer by Hardware Emulation of Acoustic-Band Optical Noise

    Directory of Open Access Journals (Sweden)

    Lipiński Marcin

    2016-06-01

    Full Text Available The low-frequency optical-signal phase noise induced by mechanical vibration of the base occurs in field-deployed fibers. Typical telecommunication data transfer is insensitive to this type of noise but the phenomenon may influence links dedicated to precise Time and Frequency (T&F fiber-optic transfer that exploit the idea of stabilization of phase or propagation delay of the link. To measure effectiveness of suppression of acoustic noise in such a link, a dedicated measurement setup is necessary. The setup should enable to introduce a low-frequency phase corruption to the optical signal in a controllable way. In the paper, a concept of a setup in which the mechanically induced acoustic-band optical signal phase corruption is described and its own features and measured parameters are presented. Next, the experimental measurement results of the T&F transfer TFTS-2 system’s immunity as a function of the fibre-optic length vs. the acoustic-band noise are presented. Then, the dependency of the system immunity on the location of a noise source along the link is also pointed out.

  5. Restoration of Normal Frequency Affected by Small Load Variations Through HVDC link Using Neuro-Fuzzy Approach

    Directory of Open Access Journals (Sweden)

    Anil Kumar Sharma,

    2011-03-01

    Full Text Available HVDC power transmission is coming up with merits to replace the EHV-AC system. The controller inverter operation can successfully regulate the power in HVDC link leading to fulfillment ofpower demand in A.C. networks caused by sudden rise in loading. Since overloading and unloading both lead to the departure of operating frequency below or above normal, its control for normalization isexercised through control of power flow in HVDC Link. Also the same is achieved by adjusting firing delay angle intelligently. This paper aims at providing automation to frequency normalization after it hasundergone changes from normal value of 50 Hz, due to sudden and sustained increase in load or due to working of generations at increased loads in H.V.D.C transmission systems. It is planned to automate the restoration of departed frequency to normal value by arranging the change in firing delay angle i.e. α of the converter of H.V.D.C. link till the increased load demand is met with. An adaptive control system has been devised which controls the firing delay angle on the basis of decisions given by a fuzzy controller. Also the fuzzy controls are decided by the departure in frequency from normal. The results have been found to be encouraging.

  6. A Cs-Based Optical Frequency Measurement Using Cross-Linked Optical and Microwave Oscillators

    CERN Document Server

    Tamm, Chr; Lipphardt, B; Gerginov, V; Nemitz, N; Kazda, M; Weyers, S; Peik, E

    2013-01-01

    We describe a measurement of the frequency of the 2S1/2(F = 0) - 2D3/2(F' = 2) transition of 171Yb+ at the wavelength 436 nm (frequency 688 THz), using a single Yb+ ion confined in a Paul trap and two caesium fountains as references. In one of the fountains, the frequency of the microwave oscillator that interrogates the caesium atoms is stabilized by the laser that excites the Yb+ reference transition with a linewidth in the hertz range. The stability is transferred to the microwave oscillator with the use of a fiber laser based optical frequency comb generator that also provides the frequency conversion for the absolute frequency measurement. The frequency comb generator is configured as a transfer oscillator so that fluctuations of the pulse repetition rate and of the carrier offset frequency do not degrade the stability of the frequency conversion. The phase noise level of the generated ultrastable microwave signal is comparable to that of a cryogenic sapphire oscillator. For fountain operation with optic...

  7. Hilbert Transform based Quadrature Hybrid RF Photonic Coupler via a Micro-Resonator Optical Frequency Comb Source

    CERN Document Server

    Nguyen, Thach G; Chu, Sai T; Little, Brent E; Morandotti, Roberto; Mitchell, Arnan; Moss, David J

    2015-01-01

    We demonstrate a photonic RF Hilbert transformer for broadband microwave in-phase and quadrature-phase generation based on an integrated frequency optical comb, generated using a nonlinear microring resonator based on a CMOS compatible, high-index contrast, doped-silica glass platform. The high quality and large frequency spacing of the comb enables filters with up to 20 taps, allowing us to demonstrate a quadrature filter with more than a 5-octave (3 dB) bandwidth and an almost uniform phase response.

  8. 凝泵变频改造浅析%Analysis of the Condensate Pump Frequency Conversion Transformation

    Institute of Scientific and Technical Information of China (English)

    熊丽萍; 王福忠

    2013-01-01

    介绍某发电厂凝泵电动机变频改造方案、节能效果、实施中存在的问题及注意事项,抛砖引玉,为今后进行变频改造的单位和项目提供宝贵的经验,为节能降耗工作贡献微薄之力。%Introduced a power plant condensate pump motor frequency transformation plan, energy saving effect and the problems and matters in the implementation, hoped this thesis can throw away a brick in order to get jade gem and provide valuable experience of the frequency transformation for future projects and departments. It can make a modest contribution towards saving energy and reducing consumption.

  9. On frequency optimization of assymetric resonant inductive coupling wireless power transfer links

    OpenAIRE

    2014-01-01

    Resonant Inductive Coupling Wireless Power Transfer (RIC-WPT) is a leading field of research due to the growing number of applications that can benefit from this technology: from biomedical implants to consumer electronics, fractionated spacecraft and electric vehicles amongst others. However, current applications are limited to symetric point-to-point-links. New challenges and applications of RIC-WPT emphasize the necessity to explore, predict and optimize the behavior of these links for dif...

  10. Impact of frequency modulation ratio on capacitor cells balancing in phase-shifted PWM based chain-link STATCOM

    DEFF Research Database (Denmark)

    Behrouzian, Ehsan; Bongiorno, Massimo; Teodorescu, Remus

    2014-01-01

    The purpose of this paper is to investigate the impact of switching harmonics on the instantaneous power that flows in the cells of a chain-link based STATCOM when using Phase-Shifted PWM. Two different cases are investigated for the converter cells: low, and high switching frequency. It is shown...... distribution among cells of the same phase leg, thus contributing to the capacitors balancing. Theoretical conclusions are validated through PSCAD simulation results....

  11. Study of the generator/motor operation of induction machines in a high frequency link space power system

    Science.gov (United States)

    Lipo, Thomas A.; Sood, Pradeep K.

    1987-01-01

    Static power conversion systems have traditionally utilized dc current or voltage source links for converting power from one ac or dc form to another since it readily achieves the temporary energy storage required to decouple the input from the output. Such links, however, result in bulky dc capacitors and/or inductors and lead to relatively high losses in the converters due to stresses on the semiconductor switches. The feasibility of utilizing a high frequency sinusoidal voltage link to accomplish the energy storage and decoupling function is examined. In particular, a type of resonant six pulse bridge interface converter is proposed which utilizes zero voltage switching principles to minimize switching losses and uses an easy to implement technique for pulse density modulation to control the amplitude, frequency, and the waveshape of the synthesized low frequency voltage or current. Adaptation of the proposed topology for power conversion to single-phase ac and dc voltage or current outputs is shown to be straight forward. The feasibility of the proposed power circuit and control technique for both active and passive loads are verified by means of simulation and experiment.

  12. [Research of dual-photoelastic-modulator-based beat frequency modulation and Fourier-Bessel transform imaging spectrometer].

    Science.gov (United States)

    Wang, Zhi-Bin; Zhang, Rui; Wang, Yao-Li; Huang, Yan-Fei; Chen, You-Hua; Wang, Li-Fu; Yang, Qiang

    2014-02-01

    As the existing photoelastic-modulator(PEM) modulating frequency in the tens of kHz to hundreds of kHz between, leading to frequency of modulated interference signal is higher, so ordinary array detector cannot effectively caprure interference signal..A new beat frequency modulation method based on dual-photoelastic-modulator (Dual-PEM) and Fourier-Bessel transform is proposed as an key component of dual-photoelastic-modulator-based imaging spectrometer (Dual-PEM-IS) combined with charge coupled device (CCD). The dual-PEM are operated as an electro-optic circular retardance modulator, Operating the PEMs at slightly different resonant frequencies w1 and w2 respectively, generates a differential signal at a much lower heterodyne frequency that modulates the incident light. This method not only retains the advantages of the existing PEM, but also the frequency of modulated photocurrent decreased by 2-3 orders of magnitude (10-500 Hz) and can be detected by common array detector, and the incident light spectra can be obtained by Fourier-Bessel transform of low frequency component in the modulated signal. The method makes the PEM has the dual capability of imaging and spectral measurement. The basic principle is introduced, the basic equations is derived, and the feasibility is verified through the corresponding numerical simulation and experiment. This method has' potential applications in imaging spectrometer technology, and analysis of the effect of deviation of the optical path difference. This work provides the necessary theoretical basis for remote sensing of new Dual-PEM-IS and for engineering implementation of spectra inversion.

  13. Stability of the proton-to-electron mass ratio tested with molecular spectroscopy using an optical link to frequency reference

    Energy Technology Data Exchange (ETDEWEB)

    Amy-Klein, Anne; Lopez, Olivier; Daussy, Christophe; Kefelian, Fabien; Chardonnet, Christian [LPL, CNRS, Universite Paris-13, Villetaneuse (France); Shelkovnikov, Alexander [LPL, CNRS, Universite Paris-13, Villetaneuse (France); Lebedev Physical Institute, Moscow (Russian Federation); Butcher, Robert J. [LPL, CNRS, Universite Paris-13, Villetaneuse (France); Cavendish Laboratory, Cambridge (United Kingdom); Jiang, Haifeng; Santarelli, Giorgio [LNE-SYRTE, Observatoire de Paris, CNRS, UPMC (France)

    2010-07-01

    Time and frequency metrology has experienced a lot of developments since ten years leading to the possibility of many fundamental tests of physics, as, for example, the search for a temporal variation of fundamental constants. However these tests are limited to macroscopic resonators or atomic systems while molecular systems are still difficult to probe with a high sensitivity, since experiments on molecules lacks of absolute frequency measurements set-ups. In that context, we have developed an optical link between our lab and the LNE-SYRTE, which allows us to benefit from their frequency references. Using this link, we performed the first experimental comparison of a molecular clock to an atomic clock, which gives a direct line to the proton-to-electron mass ratio stability. Recently, we extended the frequency dissemination technique to non-dedicated fibers of the telecommunication network simultaneously carrying digital data from the Internet traffic. This is very challenging for the development of transcontinental atomic and molecular clocks comparisons.

  14. Phase Coherent Link of an Atomic Clock to a Self-Referenced Microresonator Frequency Comb

    CERN Document Server

    Del'Haye, Pascal; Fortier, Tara; Beha, Katja; Cole, Daniel C; Yang, Ki Youl; Lee, Hansuek; Vahala, Kerry J; Papp, Scott B; Diddams, Scott A

    2015-01-01

    The counting and control of optical cycles of light has become common with modelocked laser frequency combs. But even with advances in laser technology, modelocked laser combs remain bulk-component devices that are hand-assembled. In contrast, a frequency comb based on the Kerr-nonlinearity in a dielectric microresonator will enable frequency comb functionality in a micro-fabricated and chip-integrated package suitable for use in a wide-range of environments. Such an advance will significantly impact fields ranging from spectroscopy and trace gas sensing, to astronomy, communications, atomic time keeping and photonic data processing. Yet in spite of the remarkable progress shown over the past years, microresonator frequency combs ("microcombs") have still been without the key function of direct f-2f self-referencing and phase-coherent frequency control that will be critical for enabling their full potential. Here we realize these missing elements using a low-noise 16.4 GHz silicon chip microcomb that is coher...

  15. Mammalian cell-transforming potential of traffic-linked ultrafine particulate matter PM0.056 in urban roadside atmosphere.

    Science.gov (United States)

    Verma, Mukesh K; Poojan, Shiv; Sultana, Sarwat; Kumar, Sushil

    2014-09-01

    We examined the clastogenic and cell-transforming potential of ultrafine particulate matter fraction PM0.056 of urban ambient aerosol using mammalian cells. PM1.0, PM0.56 and PM0.056 fractions were sampled from roadside atmosphere of an urban area using the cascade impactor MOUDI-NR-110. The potential to induce cytotoxicity, DNA damage and micronuclei formation was examined at the test concentrations of 3, 6, 12.5, 25, 50 and 100 μg/ml using the 3-4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, the plasmid relaxation assay and the C3H10T1/2 (10T1/2) cells. The cell-transforming potential was investigated in vitro using 10T1/2 cell transformation assay and the soft agar assay. PM1, PM0.56 and PM0.056 fractions were found to be toxic in dose-dependent manner. These induced cytotoxicity at five test concentrations, the ultrafine particle fraction PM0.056 showed greater cytotoxic potential. PM0.056 induced micronucleus formation in 10T1/2 cells. The effect was statistically significant. The DNA-damaging potential was measured in a plasmid relaxation assay. Both fine and ultrafine particle fraction PM0.56 and PM0.056 displayed greater effect as compared to larger PM1 fraction. DNA damage was found to be dependent on particulate matter intrinsic pro-oxidant chemicals. The ability of the ultrafine particle fraction PM0.056 to induce morphological cell transformation was demonstrated by significant and dose-dependent increases in type III focus formation by morphologically transformed cells in culture flasks and their clonal expansion in soft agar. It is concluded that the traffic-linked ultrafine particle fraction PM0.056 in the atmosphere by the roadside of an urban area is clastogenic and able to induce morphological transformation of mammalian cells.

  16. High-Frequency Link Inverter for Fuel CellsBased on Multiple-Carrier PWM

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A similar circuit as Fig. 12 can be realized with MOSFET or IGBT devices configured as bi-directional pairs in the output bridge. In this case, the complete process in Fig. 8 would be needed to generate the complete 50% gate drive pulses. The 50% gate pulses still support pulse transformer coupling, retaining the simplicity of the gate drive isolation. The PWM cycloconverter process scales directly to higher switching speeds possible with these devices.

  17. Observation of radiation-specific damage in human cells exposed to depleted uranium: dicentric frequency and neoplastic transformation as endpoints.

    Science.gov (United States)

    Miller, A C; Xu, J; Stewart, M; Brooks, K; Hodge, S; Shi, L; Page, N; McClain, D

    2002-01-01

    Depleted uranium (DU) is a dense heavy metal used primarily in military applications. Published data from our laboratory have demonstrated that DU exposure in vitro to immortalised human osteoblast cells (HOS) is both neoplastically transforming and genotoxic. DU possesses both a radiological (alpha-particle) and chemical (metal) component. Since DU has a low specific activity in comparison to natural uranium, it is not considered to be a significant radiological hazard. The potential contribution of radiation to DU-induced biological effects is unknown and the involvement of radiation in DU-induced biological effects could have significant implications for current risk estimates for internalised DU exposure. Two approaches were used to address this question. The frequency of dicentrics was measured in HOS cells following DU exposure in vitro. Data demonstrated that DU exposure (50 microM, 24 h) induced a significant elevation in dicentric frequency in vitro in contrast to incubation with the heavy metals, nickel and tungsten which did not increase dicentric frequency above background levels. Using the same concentration (50 microM) of three uranyl nitrate compounds that have different uranium isotopic concentrations and therefore, different specific activities, the effect on neoplastic transformation in vitro was examined. HOS cells were exposed to one of three-uranyl nitrate compounds (238U-uranyl nitrate, specific activity 0.33 microCi.g-1; DU-uranyl nitrate, specific activity 0.44 microCi.g-1; and 235U-uranyl nitrate, specific activity 2.2 microCi.g-1) delivered at a concentration of 50 microM for 24 h. Results showed, at equal uranium concentration, there was a specific activity dependent increase in neoplastic transformation frequency. Taken together these data suggest that radiation can play a role in DU-induced biological effects in vitro.

  18. Observation of radiation-specific damage in human cells exposed to depleted uranium: dicentric frequency and neoplastic transformation as endpoints

    Energy Technology Data Exchange (ETDEWEB)

    Miller, A.C.; Xu, J.; Stewart, M.; Brooks, K.; Hodge, S.; Shi, L.; Page, M.; McClain, D

    2002-07-01

    Depleted uranium (DU) is a dense heavy metal used primarily in military applications. Published data from our laboratory have demonstrated that DU exposure in vitro to immortalised human osteoblast cells (HOS) is both neoplastically transforming and genotoxic. DU possesses both a radiological (alpha-particle) and chemical (metal) component. Since DU has a low specific activity in comparison to natural uranium, it is not considered to be a significant radiological hazard. The potential contribution of radiation to DU-induced biological effects is unknown and the involvement of radiation in DU-induced biological effects could have significant implication for current risk estimates for internalised DU exposure. Two approaches were used to address this question. The frequency of dicentrics was measured in HOS cells following DU exposure in vitro. Data demonstrated that DU exposure (50 {mu}M, 24h) induced a significant elevation in dicentric frequency in vitro in contrast to incubation with the heavy metals, nickel and tungsten which did not increase dicentric frequency above background levels. Using the same concentration (50 {mu}M) of three uranyl nitrate compounds that have different uranium isotopic concentrations and therefore, different specific activities, the effect on neoplastic transformation in vitro was examined. HOS cells were exposed to one of three-uranyl nitrate compounds ({sup 238}U-uranyl nitrate, specific activity 0.33 {mu}Ci.g{sup -1}: DU-uranyl nitrate, specific activity 0.44 {mu}Ci.g{sup -1}: and {sup 235}U-uranyl nitrate, specific activity 2.2 {mu}Ci.g{sup -1}) delivered at a concentration of 50 {mu}M for 24 h. Results showed, at equal uranium concentration, there was a specific activity dependent increase in neoplastic transformation frequency. Taken together these data suggest that radiation can play a role in DU-induced biological effects in vitro. (author)

  19. Links Between Flood Frequency and Annual Water Balance Behaviors: A Basis for Similarity and Regionalization

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Jiali; Li, Hongyi; Leung, Lai-Yung R.; Guo, Shenglian; Liu, Pan; Sivapalan, Murugesu

    2014-03-28

    This paper presents the results of a data based comparative study of several hundred catchments across continental United States belonging to the MOPEX dataset, which systematically explored the connection between the flood frequency curve and measures of mean annual water balance. Two different measures of mean annual water balance are used: (i) a climatic aridity index, AI, which is a measure of the competition between water and energy availability at the annual scale; and, (ii) baseflow index, BFI, the ratio of slow runoff to total runoff also at the annual time scale, reflecting the role of geology, soils, topography and vegetation. The data analyses showed that the aridity index, AI, has a first order control on both the mean and Cv of annual maximum floods. While mean annual flood decreases with increasing aridity, Cv increases with increasing aridity. BFI appeared to be a second order control on the magnitude and shape of the flood frequency curve. Higher BFI, meaning more subsurface flow and less surface flow leads to a decrease of mean annual flood whereas lower BFI leads to accumulation of soil moisture and increased flood magnitudes that arise from many events acting together. The results presented in this paper provide innovative means to delineate homogeneous regions within which the flood frequency curves can be assumed to be functionally similar. At another level, understanding the connection between annual water balance and flood frequency will be another building block towards developing comprehensive understanding of catchment runoff behavior in a holistic way.

  20. Microwave photonic frequency down-conversion link based on intensity and phase paralleled modulation

    Science.gov (United States)

    Li, Jingnan; Wang, Yunxin; Wang, Dayong; Du, Haozheng; Zhou, Tao; Zhong, Xin; Yang, Dengcai; Li, Hongli

    2016-01-01

    A photonic microwave down-conversion approach is proposed and experimentally demonstrated based on a Mach-Zehnder modulator paralleled with a phase modulator. The incident radio frequency signal and the local oscillator signal are feed to the MZM and PM, respectively, and these two modulated optical signals interfere in the coupler. The useless higher-order sidebands are removed by a tunable optical band-pass filter. The principle of microwave frequency down-conversion is analyzed theoretically, the MZM and PM paralleled frequency down-conversion system is built. Then the performance of system is tested, and the experimental results show that the spurious-free dynamic range achieves 104.8 dB:Hz2/3. Compared to the conventional MZM-MZM cascaded system, the SFDR has been improved by 16 dB. The MZM and PM paralleled frequency down-conversion system can balance the intensity of the two coherent beams easily, and only single DC bias is needed. The proposed method possesses simple structure and high dynamic range.

  1. Frequency of Evaluation as a Measure of Links Between Levels in School Organizations.

    Science.gov (United States)

    Utande, Emmanuel A.; Dornbusch, Sanford M.

    The frequency of evaluation across organizational levels (i.e., evaluation of inferiors by superiors) is related to three variables: the existence of bureaucratic rules, availability of information across levels, and interaction among participants. In a processual perspective, as opposed to a structural one, evaluation is viewed as a key mechanism…

  2. Gesture Frequency Linked Primarily to Story Length in 4-10-Year Old Children's Stories

    Science.gov (United States)

    Nicoladis, Elena; Marentette, Paula; Navarro, Samuel

    2016-01-01

    Previous studies have shown that older children gesture more while telling a story than younger children. This increase in gesture use has been attributed to increased story complexity. In adults, both narrative complexity and imagery predict gesture frequency. In this study, we tested the strength of three predictors of children's gesture use in…

  3. Characterization of In-Body to On-Body Wireless Radio Frequency Link for Upper Limb Prostheses

    Science.gov (United States)

    Stango, Antonietta; Yazdandoost, Kamya Yekeh; Negro, Francesco; Farina, Dario

    2016-01-01

    Wireless implanted devices can be used to interface patients with disabilities with the aim of restoring impaired motor functions. Implanted devices that record and transmit electromyographic (EMG) signals have been applied for the control of active prostheses. This simulation study investigates the propagation losses and the absorption rate of a wireless radio frequency link for in-to-on body communication in the medical implant communication service (MICS) frequency band to control myoelectric upper limb prostheses. The implanted antenna is selected and a suitable external antenna is designed. The characterization of both antennas is done by numerical simulations. A heterogeneous 3D body model and a 3D electromagnetic solver have been used to model the path loss and to characterize the specific absorption rate (SAR). The path loss parameters were extracted and the SAR was characterized, verifying the compliance with the guideline limits. The path loss model has been also used for a preliminary link budget analysis to determine the feasibility of such system compliant with the IEEE 802.15.6 standard. The resulting link margin of 11 dB confirms the feasibility of the system proposed. PMID:27764182

  4. Impact of turbulence on high-precision ground-satellite frequency transfer with two-way coherent optical links

    Science.gov (United States)

    Robert, Clélia; Conan, Jean-Marc; Wolf, Peter

    2016-03-01

    Bidirectional ground-satellite laser links suffer from turbulence-induced scintillation and phase distortion. We study the impact of turbulence on coherent detection and the related phase noise that restricts time and frequency transfer precision. We evaluate the capacity to obtain a two-way cancellation of atmospheric effects despite the asymmetry between up- and downlink that limits the link reciprocity. For ground-satellite links, the asymmetry is induced by point-ahead angle and possibly the use, for the ground terminal, of different transceiver diameters, in reception and emission. The quantitative analysis is obtained thanks to refined end-to-end simulations under realistic turbulence and wind conditions as well as satellite kinematics. These temporally resolved simulations allow characterizing the coherent detection in terms of time series of heterodyne efficiency and phase noise for different system parameters. We show that tip-tilt correction on ground is mandatory at reception for the downlink and as a pre-compensation of the uplink. Besides, thanks to the large tilt angular correlation, the correction is shown to be efficient on uplink despite the point-ahead angle. Very good two-way compensation of turbulent effects is obtained even with the asymmetries. The two-way differential phase noise is reduced to 1 rad2 , with the best fractional frequency stability below 2 ×10-17 after 1-s averaging time.

  5. Time and frequency transfer with a microwave link in the ACES/PHARAO mission

    CERN Document Server

    Delva, P; Wolf, P; Poncin-Lafitte, C Le; Laurent, P

    2012-01-01

    The Atomic Clocks Ensemble in Space (ACES/PHARAO mission), which will be installed on board the International Space Station (ISS), uses a dedicated two-way Micro-Wave Link (MWL) in order to compare the timescale generated on board with those provided by many ground stations disseminated on the Earth. Phase accuracy and stability of this long range link will have a key role in the success of the ACES/PHARAO experiment. SYRTE laboratory is heavily involved in the design and development of the data processing software : from theoretical modelling and numerical simulations to the development of a software prototype. Our team is working on a wide range of problems that need to be solved in order to achieve high accuracy in (almost) real time. In this article we present some key aspects of the measurement, as well as current status of the software's development.

  6. The link between texting and motor vehicle collision frequency in the orthopaedic trauma population

    Directory of Open Access Journals (Sweden)

    Neil M. Issar

    2013-07-01

    Full Text Available BACKGROUND: This study will evaluate whether or not texting frequency while driving and/or texting frequency in general are associated with an increased risk of incurring a motor vehicle collision (MVC resulting in orthopaedic trauma injuries. METHODS: All patients who presented to the Vanderbilt University Medical Center Orthopaedic Trauma Clinic were administered a questionnaire to determine background information, mean phone use, texting frequency, texting frequency while driving, and whether or not the injury was the result of an MVC in which the patient was driving. RESULTS: 237 questionnaires were collected. 60 were excluded due to incomplete date, leaving 57 questionnaires in the MVC group and 120 from patients with non-MVC injuries. Patients who sent more than 30 texts per week (“heavy texters” were 2.22 times more likely to be involved in an MVC than those who texted less frequently. 84% of respondents claimed to never text while driving. Dividing the sample into subsets on the basis of age (25 years of age or below considered “young adult,” and above 25 years of age considered “adult”,young, heavy texters were 6.76 times more likely to be involved in an MVC than adult non-heavy texters (p = 0.000. Similarly, young adult, non-heavy texters were 6.65 (p = 0.005 times more likely to be involved in an MVC, and adult, heavy texters were 1.72 (p = 0.186 times more likely to be involved in an MVC. CONCLUSIONS: Patients injured in an MVC sent more text messages per week than non-MVC patients. Additionally, controlling for age demonstrated that young age and heavy general texting frequency combined had the highest increase in MVC risk, with the former being the variable of greatest effect

  7. Radio-Frequency Down-Conversion via Sampled Analog Optical Links

    Science.gov (United States)

    2010-08-09

    and spurious-free dynamic range) may also be theoretically calculated for a link which does not utilize optical amplifiers, the use of an EDFA in this...black curve in Fig. 3] is amplified with a commercial erbium-doped fiber amplifier ( EDFA , JDS Uniphase OA 400) and appropriately polarized with a...namely input and output thermal noise, shot noise, and additional noise arising from the presence of an optical amplifier (here, an EDFA ). The total

  8. DC-DC Type High-Frequency Link DC for Improved Power Quality of Cascaded Multilevel Inverter

    Science.gov (United States)

    Sadikin, Muhammad; Senjyu, Tomonobu; Yona, Atsushi

    2013-06-01

    Multilevel inverters are emerging as a new breed of power converter options for power system applications. Recent advances in power switching devices enabled the suitability of multilevel inverters for high voltage and high power applications because they are connecting several devices in series without the need of component matching. Usually, a transformerless battery energy storage system, based on a cascaded multilevel inverter, is used as a measure for voltage and frequency deviations. System can be reduced in size, weight, and cost of energy storage system. High-frequency link circuit topology is advantageous in realizing compact and light-weight power converters for uninterruptible power supply systems, new energy systems using photovoltaic-cells, fuel-cells and so on. This paper presents a DC-DC type high-frequency link DC (HFLDC) cascaded multilevel inverter. Each converter cell is implemented a control strategy for two H-bridge inverters that are controlled with the same multicarrier pulse width modulation (PWM) technique. The proposed cascaded multilevel inverter generates lower voltage total harmonic distortion (THD) in comparison with conventional cascaded multilevel inverter. Digital simulations are carried out using PSCAD/EMTDC to validate the performance of the proposed cascaded multilevel inverter.

  9. Detailed High Frequency Models of Various Winding Types in Power Transformers

    DEFF Research Database (Denmark)

    Pedersen, Kenneth; Lunow, Morten Erlandsson; Holbøll, Joachim

    2005-01-01

    Abstract--In this paper, techniques are described which demonstrate how a highly detailed internal transformer model can be obtained systematically with Matlab and how it can be prepared for subsequent transient analysis. The input of such a model will mainly be the description of the cross secti...

  10. Dual Transformer Model based on Standard Circuit Elements for the Study of Low- and Mid-frequency Transients

    Science.gov (United States)

    Jazebi, Saeed

    This thesis is a step forward toward achieving the final objective of creating a fully dual model for transformers including eddy currents and nonlinearities of the iron core using the fundamental electrical components already available in the EMTP-type programs. The model is effective for the study of the performance of transformers during power system transients. This is very important for transformer designers, because the insulation of transformers is determined with the overvoltages caused by lightning or switching operations. There are also internally induced transients that occur when a switch is actuated. For example switching actions for reconfiguration of distribution systems that offers economic advantages, or protective actions to clear faults and large short-circuit currents. Many of the smart grid concepts currently under development by many utilities rely heavily on switching to optimize resources that produce transients in the system. On the other hand, inrush currents produce mechanical forces which deform transformer windings and cause malfunction of the differential protection. Also, transformer performance under ferroresonance and geomagnetic induced currents are necessary to study. In this thesis, a physically consistent dual model applicable to single-phase two-winding transformers is proposed. First, the topology of a dual electrical equivalent circuit is obtained from the direct application of the principle of duality. Then, the model parameters are computed considering the variations of the transformer electromagnetic behavior under various operating conditions. Current modeling techniques use different topological models to represent diverse transient situations. The reversible model proposed in this thesis unifies the terminal and topological equivalent circuits. The model remains invariable for all low-frequency transients including deep saturation conditions driven from any of the two windings. The very high saturation region of the

  11. An Ultrahigh Frequency Partial Discharge Signal De-Noising Method Based on a Generalized S-Transform and Module Time-Frequency Matrix

    Directory of Open Access Journals (Sweden)

    Yushun Liu

    2016-06-01

    Full Text Available Due to electromagnetic interference in power substations, the partial discharge (PD signals detected by ultrahigh frequency (UHF antenna sensors often contain various background noises, which may hamper high voltage apparatus fault diagnosis and localization. This paper proposes a novel de-noising method based on the generalized S-transform and module time-frequency matrix to suppress noise in UHF PD signals. The sub-matrix maximum module value method is employed to calculate the frequencies and amplitudes of periodic narrowband noise, and suppress noise through the reverse phase cancellation technique. In addition, a singular value decomposition de-noising method is employed to suppress Gaussian white noise in UHF PD signals. Effective singular values are selected by employing the fuzzy c-means clustering method to recover the PD signals. De-noising results of simulated and field detected UHF PD signals prove the feasibility of the proposed method. Compared with four conventional de-noising methods, the results show that the proposed method can suppress background noise in the UHF PD signal effectively, with higher signal-to-noise ratio and less waveform distortion.

  12. Impairment assessment of orthogonal frequency division multiplexing over dispersion-managed links in backbone and backhaul networks

    Science.gov (United States)

    Tamilarasan, Ilavarasan; Saminathan, Brindha; Murugappan, Meenakshi

    2016-04-01

    The past decade has seen the phenomenal usage of orthogonal frequency division multiplexing (OFDM) in the wired as well as wireless communication domains, and it is also proposed in the literature as a future proof technique for the implementation of flexible resource allocation in cognitive optical networks. Fiber impairment assessment and adaptive compensation becomes critical in such implementations. A comprehensive analytical model for impairments in OFDM-based fiber links is developed. The proposed model includes the combined impact of laser phase fluctuations, fiber dispersion, self phase modulation, cross phase modulation, four-wave mixing, the nonlinear phase noise due to the interaction of amplified spontaneous emission with fiber nonlinearities, and the photodetector noises. The bit error rate expression for the proposed model is derived based on error vector magnitude estimation. The performance analysis of the proposed model is presented and compared for dispersion compensated and uncompensated backbone/backhaul links. The results suggest that OFDM would perform better for uncompensated links than the compensated links due to the negligible FWM effects and there is a need for flexible compensation. The proposed model can be employed in cognitive optical networks for accurate assessment of fiber-related impairments.

  13. A simplified pretreatment method for the determination of polychlorinated biphenyls in transformer oil by enzyme-linked immunosorbent assay

    Energy Technology Data Exchange (ETDEWEB)

    Aranami, K.; Morita, M. [National Inst. for Environmental Studies, Tsukuba (Japan); Okuyama, A. [EnBio Tec Laboratories Co. Ltd., Tokyo (Japan)

    2005-07-01

    This paper presented a simplified pretreatment method for determining polychlorinated biphenyls (PCBs) in transformer oil using enzyme-linked immunosorbent assay (ELISA). The method used a combination of dimethylsulfoxide (DMSO) and hexane partition and solid phase extraction. Kanechlors (KC) was used along with a transformer oil comprised of paraffin, naphthene, and aromatic hydrocarbons. Waste oil samples contaminated with PCBs were prepared by adding KC to the oil. Capillary column gas chromatography electron capture detection (GC-ECD) was used to analyze the samples. Qualitative and quantitative measurements of KC and the oil were conducted. An ELISA kit was then used to analyze PCB samples in DMSO and horseradish peroxidase (HRP) PCB competitors in TBS. A sulfuric acid/silica gel cartridge was used to purify the samples with n-hexane solutions. The ratio of the DMSO/hexane partition was examined. Results showed that the ELISA system is subject to negative interference in the presence of hydrocarbon co-contaminations. It was suggested that the oil matrix must be eliminated in order to detect PCB using the system. A simplified pretreatment was then developed which included direct addition of waste oil samples to the silica cartridge followed by elution with hexane. ELISA values of the pretreatment samples were corrected by multiplying dilution factors. It was concluded that the method successfully pretreated samples in approximately 10 minutes. 10 refs., 3 figs.

  14. An Intermediate Frequency Acquisition Scheme for S-band Single Access Link of the Tracking and Data Relay Satellite System

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A nonzero intermediate frequency (IF) likelihood acquisition scheme designed for S-band Single Access (SSA) link of China's Tracking and Data Relay Satellite S y stem (CTDRSS) is introduced. The received signal is downconv erted to IF, and then direct sampled in IF using a 1-bit A/D. After the digital i zation, the sampled data is detected using a hybrid likelihood acquisition schem e. Using this structure, large noise figure of the analog mixer or active filter s, amplitude and phase imbalance between low-frequency in-phase and quandratur e- phase channel can be avoided. An easy designing algorithm of the acquisition sch eme is also derived. The performance and algorithm are verified by computer simu lation.

  15. Spatial transformation-enabled electromagnetic devices: from radio frequencies to optical wavelengths

    OpenAIRE

    Jiang, Zhi Hao; Turpin, Jeremy P.; Morgan, Kennith; Lu, Bingqian; Werner, Douglas H.

    2015-01-01

    Transformation optics provides scientists and engineers with a new powerful design paradigm to manipulate the flow of electromagnetic waves in a user-defined manner and with unprecedented flexibility, by controlling the spatial distribution of the electromagnetic properties of a medium. Using this approach, over the past decade, various previously undiscovered physical wave phenomena have been revealed and novel electromagnetic devices have been demonstrated throughout the electromagnetic spe...

  16. Devil’s Vortex Phase Structure as Frequency Plane Mask for Image Encryption Using the Fractional Mellin Transform

    Directory of Open Access Journals (Sweden)

    Sunanda Vashisth

    2014-01-01

    Full Text Available A frequency plane phase mask based on Devil’s vortex structure has been used for image encryption using the fractional Mellin transform. The phase key for decryption is obtained by an iterative phase retrieval algorithm. The proposed scheme has been validated for grayscale secret target images, by numerical simulation. The efficacy of the scheme has been evaluated by computing mean-squared-error between the secret target image and the decrypted image. Sensitivity analysis of the decryption process to variations in various encryption parameters has been carried out. The proposed encryption scheme has been seen to exhibit reasonable robustness against occlusion attack.

  17. Mode transformation and frequency change with height in 3D numerical simulations of magneto-acoustic wave propagation in sunspots

    CERN Document Server

    Felipe, T; Collados, M

    2010-01-01

    Three-dimensional numerical simulations of magnetoacoustic wave propagation are performed in a sunspot atmosphere with a computational domain covering from the photosphere to the chromosphere. The wave source, with properties resembling the solar spectrum, is located at different distances from the axis of the sunspot for each simulation. These results are compared with the theory of mode transformation and also with observational features. Simulations show that the dominant oscillation frequency in the chromosphere decreases with the radial distance from the sunspot axis. The energy flux of the different wave modes involved, including de Alfv\\'en mode, is evaluated and discussed.

  18. Hysteresis effects in instantaneous frequency scaling of attenuation on 20 and 30 GHz satellite links

    Science.gov (United States)

    Sweeney, D. G.; Pratt, T.; Bostian, C. W.

    1992-01-01

    It has been observed with 20/30 GHz satellite beacon measurements that the ratio of 30 GHz to 20 GHz attenuation changes during some fade events. This ratio displays a hysteresis effect. This effect can be explained by a change in the drop size distribution (DSD) during the event. However, it appears only above approximately 6-8 dB of attenuation at 20 GHz. Instantaneous frequency scaling of attenuation is being proposed as part of an algorithm for uplink power control (ULPC) and the dynamic range of such an algorithm must be appropriately limited to avoid the hysteresis.

  19. Frequency-Modulated Microwave Photonic Links with Direct Detection: Review and Theory

    Science.gov (United States)

    2010-12-15

    approach for digital signals looks at an eye diagram and uses a Levenberg-Marquart optimization to maximize the eye opening. • LMSE / minimize ISI [56...FFT number o f po in t s etaMHz = param ( 3 ) ; % Frequency modulation e f f i c i e n c y in MHz/mA G = param ( 4 ) ; % RIM norma l i za t ion...in MHz/mA G = param ( 4 ) ; % RIM norma l i za t ion parameter PmW = param ( 5 ) ; % Opt i ca l power b e f o r e the f i l t e r s R = param ( 6

  20. ECG-Derived Respiration and Instantaneous Frequency based on the Synchrosqueezing Transform: Application to Patients with Atrial Fibrillation

    CERN Document Server

    Yi-Hsin, Chan; Shu-Shya, Hseu; Chi-Tai, Kuo; Yung-Hsin, Yeh

    2011-01-01

    The acquisition of information about respiratory patterns without directly recording the respiratory signals would be beneficial in many clinical settings. The electrocardiogram (ECG)-derived respiration (EDR) algorithm, which derives the respiratory pattern by using the information encoded in ECG signals, enables data acquisition in this manner. However, the traditional EDR algorithm cannot be used in patients with atrial fibrillation (AF) because they have highly irregular heart rates. In this paper, we first provide a definition of ideal instantaneous frequency (IIF) of respiratory signals and then describe how a novel time-frequency representation technique referred to as the Synchrosqueezing transform (SST) was used for the accurate estimation of the IIF of respiratory signals, i.e., SST-IF. Then, we introduce a new EDR algorithm based on the evaluation of the SST-IF. We tested the applicability of our new EDR algorithm in patients with comorbid cardiovascular diseases, most of which were complicated by ...

  1. X-Linked Agammagobulinemia in a Large Series of North African Patients: Frequency, Clinical Features and Novel BTK Mutations.

    Science.gov (United States)

    Aadam, Zahra; Kechout, Nadia; Barakat, Abdelhamid; Chan, Koon-Wing; Ben-Ali, Meriem; Ben-Mustapha, Imen; Zidi, Fethi; Ailal, Fatima; Attal, Nabila; Doudou, Fatouma; Abbadi, Mohamed-Cherif; Kaddache, Chawki; Smati, Leila; Touri, Nabila; Chemli, Jalel; Gargah, Tahar; Brini, Ines; Bakhchane, Amina; Charoute, Hicham; Jeddane, Leila; El Atiqi, Sara; El Hafidi, Naïma; Hida, Mustapha; Saile, Rachid; Alj, Hanane Salih; Boukari, Rachida; Bejaoui, Mohamed; Najib, Jilali; Barbouche, Mohamed-Ridha; Lau, Yu-Lung; Mellouli, Fethi; Bousfiha, Ahmed Aziz

    2016-04-01

    X-linked agammagobulinemia (XLA) is a primary immunodeficiency caused by Bruton's tyrosine kinase (BTK) gene defect. XLA patients have absent or reduced number of peripheral B cells and a profound deficiency in all immunoglobulin isotypes. This multicenter study reports the clinical, immunological and molecular features of Bruton's disease in 40 North African male patients. Fifty male out of 63 (male and female) patients diagnosed with serum agammaglobulinemia and non detectable to less than 2% peripheral B cells were enrolled. The search for BTK gene mutations was performed for all of them by genomic DNA amplification and Sanger sequencing. We identified 33 different mutations in the BTK gene in 40 patients including 12 missense mutations, 6 nonsense mutations, 6 splice-site mutations, 5 frameshift, 2 large deletions, one complex mutation and one in-frame deletion. Seventeen of these mutations are novel. This large series shows a lower frequency of XLA among male patients from North Africa with agammaglobulinemia and absent to low B cells compared with other international studies (63.5% vs. 85%). No strong evidence for genotype-phenotype correlation was observed. This study adds to other reports from highly consanguineous North African populations, showing lower frequency of X-linked forms as compared to AR forms of the same primary immunodeficiency. Furthermore, a large number of novel BTK mutations were identified and could further help identify carriers for genetic counseling.

  2. High-Frequency Heart Rate Variability Linked to Affiliation with a New Group.

    Directory of Open Access Journals (Sweden)

    Baljinder K Sahdra

    Full Text Available This study tests the hypothesis that high levels of high-frequency heart rate variability (HF-HRV predisposes individuals to affiliate with new groups. Resting cardiac physiological recordings were taken before and after experimental sessions to measure trait high-frequency heart rate variability as an index of dispositional autonomic influence on heart rate. Following an experimental manipulation of priming of caring-related words, participants engaged in a minimal group paradigm, in which they imagined being a member of one of two arbitrary groups, allocated money to members of the two groups, and rated their affiliation with the groups. High levels of HF-HRV were associated with ingroup favouritism while allocating money, an effect largely attributable to a positive relationship between HF-HRV and allocation of money to the ingroup, and less due to a negative relationship between HF-HRV and money allocation to the outgroup. HF-HRV was also associated with increased self-reported affiliation feelings for the ingroup but was unrelated to feelings towards the outgroup. These effects remained substantial even after controlling for age, gender, BMI, mood, caffeine consumption, time of day of data collection, smoking and alcohol behaviour, and respiration rate. Further, the effects were observed regardless of whether participants were primed with caring-related words or not. This study is the first to bridge a long history of research on ingroup favouritism to the relatively recent body of research on cardiac vagal tone by uncovering a positive association between HF-HRV and affiliation with a novel group.

  3. Changing air mass frequencies in Canada: potential links and implications for human health.

    Science.gov (United States)

    Vanos, J K; Cakmak, S

    2014-03-01

    Many individual variables have been studied to understand climate change, yet an overall weather situation involves the consideration of many meteorological variables simultaneously at various times diurnally, seasonally, and yearly. The current study identifies a full weather situation as an air mass type using synoptic scale classification, in 30 population centres throughout Canada. Investigative analysis of long-term air mass frequency trends was completed, drawing comparisons between seasons and climate zones. We find that the changing air mass trends are highly dependent on the season and climate zone being studied, with an overall increase of moderate ('warm') air masses and decrease of polar ('cold') air masses. In the summertime, general increased moisture content is present throughout Canada, consistent with the warming air masses. The moist tropical air mass, containing the most hot and humid air, is found to increase in a statistically significant fashion in the summertime in 46% of the areas studied, which encompass six of Canada's ten largest population centres. This emphasises the need for heat adaptation and acclimatisation for a large proportion of the Canadian population. In addition, strong and significant decreases of transition/frontal passage days were found throughout Canada. This result is one of the most remarkable transition frequency results published to date due to its consistency in identifying declining trends, coinciding with research completed in the United States (US). We discuss relative results and implications to similar US air mass trend analyses, and draw upon research studies involving large-scale upper-level air flow and vortex connections to air mass changes, to small-scale meteorological and air pollution interactions. Further research is warranted to better understand such connections, and how these air masses relate to the overall and city-specific health of Canadians.

  4. Estimation of Interchannel Time Difference in Frequency Subbands Based on Nonuniform Discrete Fourier Transform

    Directory of Open Access Journals (Sweden)

    Qiu Bo

    2008-01-01

    Full Text Available Binaural cue coding (BCC is an efficient technique for spatial audio rendering by using the side information such as interchannel level difference (ICLD, interchannel time difference (ICTD, and interchannel correlation (ICC. Of the side information, the ICTD plays an important role to the auditory spatial image. However, inaccurate estimation of the ICTD may lead to the audio quality degradation. In this paper, we develop a novel ICTD estimation algorithm based on the nonuniform discrete Fourier transform (NDFT and integrate it with the BCC approach to improve the decoded auditory image. Furthermore, a new subjective assessment method is proposed for the evaluation of auditory image widths of decoded signals. The test results demonstrate that the NDFT-based scheme can achieve much wider and more externalized auditory image than the existing BCC scheme based on the discrete Fourier transform (DFT. It is found that the present technique, regardless of the image width, does not deteriorate the sound quality at the decoder compared to the traditional scheme without ICTD estimation.

  5. Estimation of Interchannel Time Difference in Frequency Subbands Based on Nonuniform Discrete Fourier Transform

    Directory of Open Access Journals (Sweden)

    Bo Qiu

    2008-05-01

    Full Text Available Binaural cue coding (BCC is an efficient technique for spatial audio rendering by using the side information such as interchannel level difference (ICLD, interchannel time difference (ICTD, and interchannel correlation (ICC. Of the side information, the ICTD plays an important role to the auditory spatial image. However, inaccurate estimation of the ICTD may lead to the audio quality degradation. In this paper, we develop a novel ICTD estimation algorithm based on the nonuniform discrete Fourier transform (NDFT and integrate it with the BCC approach to improve the decoded auditory image. Furthermore, a new subjective assessment method is proposed for the evaluation of auditory image widths of decoded signals. The test results demonstrate that the NDFT-based scheme can achieve much wider and more externalized auditory image than the existing BCC scheme based on the discrete Fourier transform (DFT. It is found that the present technique, regardless of the image width, does not deteriorate the sound quality at the decoder compared to the traditional scheme without ICTD estimation.

  6. Increased frequency of spontaneous neoplastic transformation in progeny of bystander cells from cultures exposed to densely ionizing radiation.

    Directory of Open Access Journals (Sweden)

    Manuela Buonanno

    Full Text Available An increased risk of carcinogenesis caused by exposure to space radiation during prolonged space travel is a limiting factor for human space exploration. Typically, astronauts are exposed to low fluences of ionizing particles that target only a few cells in a tissue at any one time. The propagation of stressful effects from irradiated to neighboring bystander cells and their transmission to progeny cells would be of importance in estimates of the health risks of exposure to space radiation. With relevance to the risk of carcinogenesis, we investigated, in model C3H 10T½ mouse embryo fibroblasts (MEFs, modulation of the spontaneous frequency of neoplastic transformation in the progeny of bystander MEFs that had been in co-culture 10 population doublings earlier with MEFs exposed to moderate doses of densely ionizing iron ions (1 GeV/nucleon or sparsely ionizing protons (1 GeV. An increase (P<0.05 in neoplastic transformation frequency, likely mediated by intercellular communication through gap junctions, was observed in the progeny of bystander cells that had been in co-culture with cells irradiated with iron ions, but not with protons.

  7. A new high-frequency Agrobacterium-mediated transformation technique for Sesamum indicum L. using de-embryonated cotyledon as explant.

    Science.gov (United States)

    Chowdhury, Supriyo; Basu, Arpita; Kundu, Surekha

    2014-09-01

    In spite of the economic importance of sesame (Sesamum indicum L.) and the recent availability of its genome sequence, a high-frequency transformation protocol is still not available. The only two existing Agrobacterium-mediated transformation protocols that are available have poor transformation efficiencies of less than 2%. In the present study, we report a high-frequency, simple, and reproducible transformation protocol for sesame. Transformation was done using de-embryonated cotyledons via somatic embryogenic stages. All the critical parameters of transformation, like incubation period of explants in pre-regeneration medium prior to infection by Agrobacterium tumefaciens, cocultivation period, concentrations of acetosyringone in cocultivation medium, kanamycin concentration, and concentration of plant hormones, including 6-benzylaminopurine, have been optimized. This protocol is superior to the two existing protocols in its high regeneration and transformation efficiencies. The transformed sesame lines have been tested by PCR, RT-PCR for neomycin phosphotransferase II gene expression, and β-glucuronidase (GUS) assay. The regeneration frequency and transformation efficiency are 57.33 and 42.66%, respectively. T0 and T1 generation transgenic plants were analyzed, and several T1 plants homozygous for the transgenes were obtained.

  8. Precision measurement of the hydrogen 1S-2S frequency via a 920-km fiber link.

    Science.gov (United States)

    Matveev, Arthur; Parthey, Christian G; Predehl, Katharina; Alnis, Janis; Beyer, Axel; Holzwarth, Ronald; Udem, Thomas; Wilken, Tobias; Kolachevsky, Nikolai; Abgrall, Michel; Rovera, Daniele; Salomon, Christophe; Laurent, Philippe; Grosche, Gesine; Terra, Osama; Legero, Thomas; Schnatz, Harald; Weyers, Stefan; Altschul, Brett; Hänsch, Theodor W

    2013-06-07

    We have measured the frequency of the extremely narrow 1S-2S two-photon transition in atomic hydrogen using a remote cesium fountain clock with the help of a 920 km stabilized optical fiber. With an improved detection method we obtain f(1S-2S)=2466 061 413 187 018 (11)  Hz with a relative uncertainty of 4.5×10(-15), confirming our previous measurement obtained with a local cesium clock [C. G. Parthey et al., Phys. Rev. Lett. 107, 203001 (2011)]. Combining these results with older measurements, we constrain the linear combinations of Lorentz boost symmetry violation parameters c((TX))=(3.1±1.9)×10(-11) and 0.92c((TY))+0.40c((TZ))=(2.6±5.3)×10(-11) in the standard model extension framework [D. Colladay, V. A. Kostelecký, Phys. Rev. D. 58, 116002 (1998)].

  9. Ohmic Radio-Frequency Synergy Current Drive and Transformer Recharging Experiments in the HT-7 Tokamak

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhong-Yong; WAN Bao-Nian; SHI Yue-Jiang; HU Li-Qun; XU Han-Dong

    2005-01-01

    @@ Lower hybrid current drive (LHCD) experiments for investigating the interaction between lower hybrid (LH) wave and residual dc electric field were performed in extensive plasma parameter ranges in the HT-7 superconducting tokamak. The experimental results are well fitted to the Karney-Fisch theory on the efficiency of LH waves energy converted to poloidal magnetic field energy. The fraction of absorbed LH power is about 0.75 for the HT-7 machine, and the upshift of the LH-wave parallel refraction index during LHCD experiments have been derived by the optimizing fitting parameters. The LH wave is also used for the transformer recharging when the plasma current is maintained unchanged. The highest efficiency about 7% has been achieved in HT-7 machine.

  10. White light-emitting diode based wireless orthogonal frequency division multiplexing link with improved transmission capacity using Bayesian compressive sensing

    Science.gov (United States)

    Won, Yong-Yuk; Seo, Dong-Sun; Yoon, Sang Min

    2016-04-01

    We propose a technique that improves the channel capacity of an optical wireless orthogonal frequency division multiplexing (OFDM) transmission, which employs a visible light-emitting diode. An OFDM waveform encoded by quadrature phase shift keying (QPSK) or 16-quadrature amplitude modulation is compressed and then transformed into a sparse waveform using a proposed advanced systematic sampling. At the optical wireless receiver, the original waveform is recovered by L1-minimization based on a Bayesian compressive sensing. Our experimental results show the significant increase in the channel capacity from 31.12 to 51.87 Mbit/s at forward error correction limit (i.e., error vector magnitude of 32%) in case of QPSK symbols.

  11. Focusing vibrating targets in frequency-modulation continuous-wave-synthetic aperture radar with Doppler keystone transform

    Science.gov (United States)

    Hu, Yuxin; Zhang, Yuan; Sun, Jinping; Lei, Peng

    2016-04-01

    Vibrating targets generally induce sinusoidal micro-Doppler modulation in high resolution synthetic aperture radar (SAR). They could cause defocused and ghost results by conventional imaging algorithms. This paper proposes a method on vibrating target imaging in frequency-modulation continuous-wave (FMCW) SAR systems. The continuous motion of sensor platform during pulse time is considered in the signal model. Based on Bessel series expansion of the signal in the azimuth direction, the influence of platform motion on the azimuth frequency is eliminated after dechirp and deskew. In addition, the range walk is compensated in the two-dimensional frequency domain by Doppler keystone transform. Next, using range cell migration correction, the azimuth quadratic phase compensation and the range curvature correction are made in range-Doppler domain for the focus of paired echoes. The residual video phase of paired echoes is eliminated, and vibration parameters are estimated to compensate in the sinusoidal modulation phase. Then the deghosted image of vibrating targets can be obtained. The proposed method is applicable to multiple targets with various vibrating states due to no need of a priori knowledge of targets. Finally, simulations are carried out to validate the effectiveness of the method in FMCW-SAR imaging of vibrating targets.

  12. Modelado del transformador para eventos de alta frecuencia ;Transformer model for high frequency events

    Directory of Open Access Journals (Sweden)

    Verónica Adriana – Galván Sanchez

    2012-07-01

    Full Text Available La función de un transformador es cambiar el nivel de tensión a través de un acoplamiento magnético.Debido a su construcción física, su representación como un circuito y su modelo matemático son muycomplejos. El comportamiento electromagnético del transformador, al igual que todos los elementos de lared eléctrica de potencia, depende de la frecuencia involucrada. Por esta razón cuando se tienenfenómenos de alta frecuencia su modelo debe ser muy detallado para que reproduzca el comportamientodel estado transitorio. En este trabajo se analiza cómo se pasa de un modelo muy simple, a un modelo muydetallado para hacer simulación de eventos de alta frecuencia. Los eventos que se simulan son la operaciónde un interruptor por una falla en el sistema y el impacto de una descarga atmosférica sobre la línea detransmisión a una distancia de 5 km de una subestación de potencia.The transformer’s function is to change the voltage level through a magnetic coupling. Due to its physicalconstruction, its representation as a circuit and its mathematical model are very complex. Theelectromagnetic behavior and all the elements in the power network depend on the involved frequency. So,for high frequency events, its model needs to be very detailed to reproduce the electromagnetic transientbehavior. This work analyzes how to pass from a simple model to a very detailed model to simulated highfrequency events. The simulated events are the switch operation due to a fault in the system and the impactof an atmospheric discharge (direct stroke in the transmission line, five km far away from the substation.

  13. Homeodomain Protein Transforming Growth Factor Beta-Induced Factor 2 Like, X-Linked Function in Colon Adenocarcinoma Cells

    Science.gov (United States)

    Akbari, Abolfazl; Agah, Shahram; Heidari, Mansour; Mobini, Gholam Reza; Faghihloo, Ebrahim; Sarveazad, Arash; Mirzaei, Alireza

    2017-08-27

    Background: TGIF2LX (transforming growth factor beta-induced factor 2 like, X-linked) is a homeodomain (HD) protein that has been implicated in the negative regulation of cell signaling pathways. The aim of this study was to investigate the possible functions of TGIF2LX in colon adenocarcinoma cells. Methods: The human SW48 cell line was transfected with cDNA for the wild-type TGIF2LX gene and gene/protein over-expression was confirmed by microscopic analysis, real time RT-PCR and Western blotting techniques. In vitro cell proliferation was evaluated by MTT and BrdU assays. After developing a colon tumor model in nude mice, immunohistochemical (IHC) staining of tumor tissue was carried out for Ki-67 (proliferation) and CD34 (angiogenesis) markers. To predict potential protein partners of TGIF2LX, in-silico analysis was also conducted. Results: Obtained results showed over-expression of TGIF2LX as a potential transcription factor could inhibit either proliferation or angiogenesis (P<0.05) in colon tumors. In-silico results predicted interaction of TGIF2LX with other proteins considered important for cellular development. Conclusions: Our findings provided evidence of molecular mechanisms by which TGIF2LX could act as a tumor suppressor in colon adenocarcinoma cells. Thus, this gene may potentially be a promising option for colon cancer gene-based therapeutic strategies. Creative Commons Attribution License

  14. A three-phase current-fed dc/dc converter with a three-leg high frequency transformer for fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Hanju [Department of Electrical Engineering, Chungnam National University, 220 Gung-dong Yuseong-gu, Daejeon 305-764 (Korea); Choi, Jungwan [National Fusion Research Institute, Daejeon (Korea); Enjeti, Prasad [Texas A and M University, College Station, TX 77843-3128 (United States)

    2008-07-15

    In this paper, a three-phase current-fed dc/dc converter with an active clamp is introduced, and a new three-phase three-leg high frequency transformer is proposed for the converter. The three-phase dc/dc converter transfers power through transformer leakage inductances in the discontinuous current mode; a single common active clamp branch is employed for zero-voltage switching (ZVS) in all active switches. Further, the converter's three-phase power configuration increases power transfer, and it reduces the rms current per phase, thus reduces conduction losses. Moreover, a delta-delta connection on the three-phase transformer provides parallel current paths and reduces conduction losses in the transformer windings. A three-phase transformer can be constructed by connecting three discrete single-phase transformers, but this process results in a higher volume and higher material costs. Therefore, a new three-phase three-leg high frequency transformer is designed with three discrete cores integrated into a single transformer core. The proposed transformer is analyzed according to the several operating modes of the converter, and its design rules are determined. Experimental results are obtained on a 500-W prototype unit; the design is fully verified and analyzed. (author)

  15. Optimized discrete wavelet transforms in the cubed sphere with the lifting scheme—implications for global finite-frequency tomography

    Science.gov (United States)

    Chevrot, Sébastien; Martin, Roland; Komatitsch, Dimitri

    2012-12-01

    Wavelets are extremely powerful to compress the information contained in finite-frequency sensitivity kernels and tomographic models. This interesting property opens the perspective of reducing the size of global tomographic inverse problems by one to two orders of magnitude. However, introducing wavelets into global tomographic problems raises the problem of computing fast wavelet transforms in spherical geometry. Using a Cartesian cubed sphere mapping, which grids the surface of the sphere with six blocks or 'chunks', we define a new algorithm to implement fast wavelet transforms with the lifting scheme. This algorithm is simple and flexible, and can handle any family of discrete orthogonal or bi-orthogonal wavelets. Since wavelet coefficients are local in space and scale, aliasing effects resulting from a parametrization with global functions such as spherical harmonics are avoided. The sparsity of tomographic models expanded in wavelet bases implies that it is possible to exploit the power of compressed sensing to retrieve Earth's internal structures optimally. This approach involves minimizing a combination of a ℓ2 norm for data residuals and a ℓ1 norm for model wavelet coefficients, which can be achieved through relatively minor modifications of the algorithms that are currently used to solve the tomographic inverse problem.

  16. No effects of power line frequency extremely low frequency electromagnetic field exposure on selected neurobehavior tests of workers inspecting transformers and distribution line stations versus controls.

    Science.gov (United States)

    Li, Li; Xiong, De-fu; Liu, Jia-wen; Li, Zi-xin; Zeng, Guang-cheng; Li, Hua-liang

    2014-03-01

    We aimed to evaluate the interference of 50 Hz extremely low frequency electromagnetic field (ELF-EMF) occupational exposure on the neurobehavior tests of workers performing tour-inspection close to transformers and distribution power lines. Occupational short-term "spot" measurements were carried out. 310 inspection workers and 300 logistics staff were selected as exposure and control. The neurobehavior tests were performed through computer-based neurobehavior evaluation system, including mental arithmetic, curve coincide, simple visual reaction time, visual retention, auditory digit span and pursuit aiming. In 500 kV areas electric field intensity at 71.98% of total measured 590 spots were above 5 kV/m (national occupational standard), while in 220 kV areas electric field intensity at 15.69% of total 701 spots were above 5 kV/m. Magnetic field flux density at all the spots was below 1,000 μT (ICNIRP occupational standard). The neurobehavior score changes showed no statistical significance. Results of neurobehavior tests among different age, seniority groups showed no significant changes. Neurobehavior changes caused by daily repeated ELF-EMF exposure were not observed in the current study.

  17. On Hilbert-Huang Transform Based Synthesis of a Signal Contaminated by Radio Frequency Interference or Fringes

    Science.gov (United States)

    Kizhner, Semion; Shiri, Ron S.; Vootukuru, Meg; Coletti, Alessandro

    2015-01-01

    Norden E. Huang et al. had proposed and published the Hilbert-Huang Transform (HHT) concept correspondently in 1996, 1998. The HHT is a novel method for adaptive spectral analysis of non-linear and non-stationary signals. The HHT comprises two components: - the Huang Empirical Mode Decomposition (EMD), resulting in an adaptive data-derived basis of Intrinsic Mode functions (IMFs), and the Hilbert Spectral Analysis (HSA1) based on the Hilbert Transform for 1-dimension (1D) applied to the EMD IMF's outcome. Although paper describes the HHT concept in great depth, it does not contain all needed methodology to implement the HHT computer code. In 2004, Semion Kizhner and Karin Blank implemented the reference digital HHT real-time data processing system for 1D (HHT-DPS Version 1.4). The case for 2-Dimension (2D) (HHT2) proved to be difficult due to the computational complexity of EMD for 2D (EMD2) and absence of a suitable Hilbert Transform for 2D spectral analysis (HSA2). The real-time EMD2 and HSA2 comprise the real-time HHT2. Kizhner completed the real-time EMD2 and the HSA2 reference digital implementations respectively in 2013 & 2014. Still, the HHT2 outcome synthesis remains an active research area. This paper presents the initial concepts and preliminary results of HHT2-based synthesis and its application to processing of signals contaminated by Radio-Frequency Interference (RFI), as well as optical systems' fringe detection and mitigation at design stage. The Soil Moisture Active Passive (SMAP mission (SMAP) carries a radiometer instrument that measures Earth soil moisture at L1 frequency (1.4 GHz polarimetric - H, V, 3rd and 4th Stokes parameters). There is abundant RFI at L1 and because soil moisture is a strategic parameter, it is important to be able to recover the RFI-contaminated measurement samples (15% of telemetry). State-of-the-art only allows RFI detection and removes RFI-contaminated measurements. The HHT-based analysis and synthesis facilitates

  18. Real-Time Estimation of Power System Frequency Using a Three-Level Discrete Fourier Transform Method

    Directory of Open Access Journals (Sweden)

    Soon-Ryul Nam

    2014-12-01

    Full Text Available This paper proposes a three-level discrete Fourier transform (DFT method to provide an accurate estimate of power system frequency in real time. The first level decomposes a power system signal into two orthogonal cosine- and sine-filtered signals. The second and third levels are used to determine the amplitude ratio of the cosine- and sine-filtered signals without encountering the zero-crossing problem and with an increase in ability to suppress harmonics and inter-harmonics. The performance of the three-level DFT method is evaluated using computer-simulated signals with harmonics and inter-harmonics. The three-level DFT method is also implemented on a digital signal processor (DSP-based hardware prototype, and its performance in the hardware implementation is evaluated using a real-time digital simulator (RTDS. The evaluation results show that the three-level DFT method can achieve real-time estimation of power system frequency with satisfactory performance.

  19. Integrin-linked kinase mediates the hydrogen peroxide-dependent transforming growth factor-β1 up-regulation.

    Science.gov (United States)

    Gonzalez-Ramos, M; de Frutos, S; Griera, M; Luengo, A; Olmos, G; Rodriguez-Puyol, D; Calleros, L; Rodriguez-Puyol, M

    2013-08-01

    Transforming growth factor type-β1 (TGF-β1) has been recognized as a central mediator in many pathological events related to extracellular matrix (ECM) proteins accumulation, where their locally increased expression has been implicated in the fibrosis process of numerous organs, including glomerular fibrosis in the kidney. We and others have reported the TGF-β1 synthesis regulation by reactive oxygen species (ROS), and moreover we also described the implication of integrin-linked kinase (ILK) in the AP-1-dependent TGF-β1 up-regulation. Thus, we propose here that hydrogen peroxide (H2O2)-dependent TGF-β1 regulation may be mediated by ILK activation. First we confirmed the increase in TGF-β1 expression in human mesangial cells (HMC) after treatment with H2O2 or with an alternative H2O2-generating system such as the glucose-oxidase enzyme (GOX). By using immunoblotting, immunofluorescence, and ELISA techniques, we demonstrate that extracellular H2O2 up-regulates TGF-β1 transcription, as well as increases TGF-β1 promoter activity. Furthermore, catalase-decreased intracellular H2O2 abolished TGF-β1 up-regulation. The use of pharmacological inhibitors as well as knockdown of ILK with small interfering RNA (siRNA) demonstrated the implication of a PI3K/ILK/AKT/ERK MAPK signaling pathway axis in the H2O2-induced TGF-β1 overexpression. Finally, we explored the physiological relevance of these findings by treating HMC with angiotensin II, a known stimuli of H2O2 synthesis. Our results confirm the relevance of previous findings after a more physiological stimulus. In summary, our results provide evidence that ILK activity changes may act as a mechanism in response to different stimuli such as H2O2 in the induced TGF-β1 up-regulation in pathological or even physiological conditions.

  20. Global gene expression profiling of brown to white adipose tissue transformation in sheep reveals novel transcriptional components linked to adipose remodeling

    DEFF Research Database (Denmark)

    Basse, Astrid L.; Dixen, Karen; Yadav, Rachita

    2015-01-01

    Background: Large mammals are capable of thermoregulation shortly after birth due to the presence of brown adipose tissue (BAT). The majority of BAT disappears after birth and is replaced by white adipose tissue (WAT). Results: We analyzed the postnatal transformation of adipose in sheep....... Conclusions: Using global gene expression profiling of the postnatal BAT to WAT transformation in sheep, we provide novel insight into adipose tissue plasticity in a large mammal, including identification of novel transcriptional components linked to adipose tissue remodeling. Moreover, our data set provides...

  1. Reverse Link Outage Probabilities of Multicarrier CDMA Systems with Beamforming in the Presence of Carrier Frequency Offset

    Directory of Open Access Journals (Sweden)

    Xiaoyu Hu

    2007-11-01

    Full Text Available The outage probability of reverse link multicarrier (MC code-division multiple access (CDMA systems with beamforming in the presence of carrier frequency offset (CFO is studied. A conventional uniform linear array (ULA beamformer is utilized. An independent Nakagami fading channel is assumed for each subcarrier of all users. The outage probability is first investigated under a scenario where perfect beamforming is assumed. A closed form expression of the outage probability is derived. The impact of different types of beamforming impairments on the outage probability is then evaluated, including direction-of-arrival (DOA estimation errors, angle spreads, and mutual couplings. Numerical results show that the outage probability improves significantly as the number of antenna elements increases. The effect of CFO on the outage probability is reduced significantly when the beamforming technique is employed. Also, it is seen that small beamforming impairments (DOA estimation errors and angle spreads only affect the outage probability very slightly, and the mutual coupling between adjacent antenna elements does not affect the outage probability noticeably.

  2. Reverse Link Outage Probabilities of Multicarrier CDMA Systems with Beamforming in the Presence of Carrier Frequency Offset

    Directory of Open Access Journals (Sweden)

    Hu Xiaoyu

    2008-01-01

    Full Text Available The outage probability of reverse link multicarrier (MC code-division multiple access (CDMA systems with beamforming in the presence of carrier frequency offset (CFO is studied. A conventional uniform linear array (ULA beamformer is utilized. An independent Nakagami fading channel is assumed for each subcarrier of all users. The outage probability is first investigated under a scenario where perfect beamforming is assumed. A closed form expression of the outage probability is derived. The impact of different types of beamforming impairments on the outage probability is then evaluated, including direction-of-arrival (DOA estimation errors, angle spreads, and mutual couplings. Numerical results show that the outage probability improves significantly as the number of antenna elements increases. The effect of CFO on the outage probability is reduced significantly when the beamforming technique is employed. Also, it is seen that small beamforming impairments (DOA estimation errors and angle spreads only affect the outage probability very slightly, and the mutual coupling between adjacent antenna elements does not affect the outage probability noticeably.

  3. Fundamental frequency during couple conflict: an analysis of physiological, behavioral, and sex-linked information encoded in vocal expression.

    Science.gov (United States)

    Weusthoff, Sarah; Baucom, Brian R; Hahlweg, Kurt

    2013-04-01

    The human voice is one of the sounds most frequently experienced by human beings. During couple conflict, higher fundamental frequency (f0), a physical property of human speech, has been linked to an increased risk of divorce, less beneficial response to couple therapy, and higher levels of dysfunctional communication behavior. F0 is generally considered to be a measure of emotional arousal, but it is not currently clear whether this interpretation is appropriate for understanding spouses' f0 during couple interaction. The goal of the current article is to clarify what forms of information are encoded in f0 during couple conflict by examining the relations between f0 range, physiological variables, and communication behavior during the conflict discussions of 67 German couples. In line with evolutionary models of speech production, associations emerged in the expected directions between f0 and: (a) physiological variables (e.g., heart rate, blood pressure, and cortisol); (b) self-reported communication behavior; and (c) observationally coded communication behavior. Additionally, simultaneous examination of physiological variables and observationally coded communication behaviors revealed that associations between both sets of variables and f0 range were largely independent of one another. Furthermore, women's range of f0 was significantly greater than men's range of f0. With regard to social signaling theories, f0 range can be understood as a nonverbal transmission of distress. Implications for future research on and use of f0 are discussed. (PsycINFO Database Record (c) 2013 APA, all rights reserved).

  4. A Novel Characteristic Frequency Bands Extraction Method for Automatic Bearing Fault Diagnosis Based on Hilbert Huang Transform

    Directory of Open Access Journals (Sweden)

    Xiao Yu

    2015-11-01

    Full Text Available Because roller element bearings (REBs failures cause unexpected machinery breakdowns, their fault diagnosis has attracted considerable research attention. Established fault feature extraction methods focus on statistical characteristics of the vibration signal, which is an approach that loses sight of the continuous waveform features. Considering this weakness, this article proposes a novel feature extraction method for frequency bands, named Window Marginal Spectrum Clustering (WMSC to select salient features from the marginal spectrum of vibration signals by Hilbert–Huang Transform (HHT. In WMSC, a sliding window is used to divide an entire HHT marginal spectrum (HMS into window spectrums, following which Rand Index (RI criterion of clustering method is used to evaluate each window. The windows returning higher RI values are selected to construct characteristic frequency bands (CFBs. Next, a hybrid REBs fault diagnosis is constructed, termed by its elements, HHT-WMSC-SVM (support vector machines. The effectiveness of HHT-WMSC-SVM is validated by running series of experiments on REBs defect datasets from the Bearing Data Center of Case Western Reserve University (CWRU. The said test results evidence three major advantages of the novel method. First, the fault classification accuracy of the HHT-WMSC-SVM model is higher than that of HHT-SVM and ST-SVM, which is a method that combines statistical characteristics with SVM. Second, with Gauss white noise added to the original REBs defect dataset, the HHT-WMSC-SVM model maintains high classification accuracy, while the classification accuracy of ST-SVM and HHT-SVM models are significantly reduced. Third, fault classification accuracy by HHT-WMSC-SVM can exceed 95% under a Pmin range of 500–800 and a m range of 50–300 for REBs defect dataset, adding Gauss white noise at Signal Noise Ratio (SNR = 5. Experimental results indicate that the proposed WMSC method yields a high REBs fault

  5. Identifying flood deposits in lake sediments: Changing frequencies and potential links to long-term climate change

    Energy Technology Data Exchange (ETDEWEB)

    Stoeren, Eivind Wilhelm Nagel

    2011-05-15

    -scale patterns in shifting flood frequency might be indicative of shifts in atmospheric circulation and can shed light on past pressure variations in the North Atlantic region, in areas not dominated by the NAO. Major shifts were found at about 2300, 1200 and 200 cal. years BP. This thesis presents and applies approaches to detect rapid geological events in lake sediment archives, and indicates that there have been significant changes in the frequency of floods and possibly debris flows over the Holocene. These changes may partly be linked to climatic, particularly precipitation, fluctuations, but also to other mechanisms such as land uplift, changing seasons and vegetation changes. (Author)

  6. Process induced transformations during tablet manufacturing: phase transition analysis of caffeine using DSC and low frequency micro-Raman spectroscopy.

    Science.gov (United States)

    Hubert, Sébastien; Briancon, Stéphanie; Hedoux, Alain; Guinet, Yannick; Paccou, Laurent; Fessi, Hatem; Puel, François

    2011-11-25

    The phase transition of a model API, caffeine Form I, was studied during tableting process monitored with an instrumented press. The formulation used had a plastic flow behavior according to the Heckel model in the compression pressure range of 70-170 MPa. The quantitative methods of analysis used were Differential Scanning Calorimetry (DSC) and low frequency Micro Raman Spectroscopy (MRS) which was used for the first time for the mapping of polymorphs in tablets. They brought complementary contributions since MRS is a microscopic spectral analysis with a spatial resolution of 5 μm(3) and DSC takes into account a macroscopic fraction (10mg) of the tablet. Phase transitions were present at the surfaces, borders and center of the tablets. Whatever the pressure applied during the compression process, the transition degree of caffeine Form I toward Form II was almost constant. MRS provided higher transition degrees (50-60%) than DSC (20-35%). MRS revealed that caffeine Form I particles were partially transformed in all parts of the tablets at a microscopic scale. Moreover, tablet surfaces showed local higher transition degree compared to the other parts.

  7. Fourier transform and Vernier spectroscopy using an optical frequency comb at 3-5.4  μm.

    Science.gov (United States)

    Khodabakhsh, Amir; Ramaiah-Badarla, Venkata; Rutkowski, Lucile; Johansson, Alexandra C; Lee, Kevin F; Jiang, Jie; Mohr, Christian; Fermann, Martin E; Foltynowicz, Aleksandra

    2016-06-01

    We present a versatile mid-infrared frequency comb spectroscopy system based on a doubly resonant optical parametric oscillator tunable in the 3-5.4 μm range and two detection methods: a Fourier transform spectrometer (FTS) and a continuous-filtering Vernier spectrometer (CF-VS). Using the FTS with a multipass cell, we measure high precision broadband absorption spectra of CH4 at 3.3 μm and NO at 5.25 μm, the latter for the first time with comb spectroscopy, and we detect atmospheric species (CH4, CO, CO2, and H2O) in air in the signal and idler ranges. Multiline fitting yields minimum detectable concentrations of 10-20  ppb Hz-1/2 for CH4, NO, and CO. For the first time in the mid-infrared, we perform CF-VS using an enhancement cavity, a grating, and a single detector, and we measure the absorption spectrum of CH4 and H2O in ambient air at ∼3.3  μm, reaching a 40 ppb concentration detection limit for CH4 in 2 ms.

  8. Fourier transform and Vernier spectroscopy using an optical frequency comb at 3-54 μm

    Science.gov (United States)

    Khodabakhsh, Amir; Ramaiah-Badarla, Venkata; Rutkowski, Lucile; Johansson, Alexandra C.; Lee, Kevin F.; Jiang, Jie; Mohr, Christian; Fermann, Martin E.; Foltynowicz, Aleksandra

    2016-06-01

    We present a versatile mid-infrared frequency comb spectroscopy system based on a doubly resonant optical parametric oscillator tunable in the 3-5.4 {\\mu}m range and two detection methods, a Fourier transform spectrometer (FTS) and a Vernier spectrometer. Using the FTS with a multipass cell we measure high-precision broadband absorption spectra of CH$_4$ and NO at ~3.3 {\\mu}m and ~5.2 {\\mu}m, respectively, and of atmospheric species (CH$_4$, CO, CO$_2$ and H$_2$O) in air in the signal and idler wavelength range. The figure of merit of the system is on the order of 10$^{-8}$ cm$^{-1}$ Hz$^{-1/2}$ per spectral element, and multiline fitting yields minimum detectable concentrations of 10-20 ppb Hz$^{-1/2}$ for CH$_4$, NO and CO. For the first time in the mid-infrared, we perform continuous-filtering Vernier spectroscopy using a low finesse enhancement cavity, a grating and a single detector, and measure the absorption spectrum of CH$_4$ and H$_2$O in ambient air at ~3.3 {\\mu}m.

  9. 新颖的正激式高频环节交-交变换器%Novel forward mode AC/AC converters with high frequency link

    Institute of Scientific and Technical Information of China (English)

    李磊; 陈道炼; 胡育文

    2003-01-01

    A circuit configuration and a circuit topologic family of the novel forward mode AC/AC converters with high frequency link are presented. The circuit configuration is constituted of input cycloconverter, high frequency transformer, output cycloconverter, input and output filters. The circuit topologic family includes eight circuit topologies, such as full-bridge-full-wave mode, etc. The bi-polarity phase-shifted control strategy and steady principles are thoroughly investigated. The output characteristics are obtained. By using the bi-polarity phase-shifted control strategy with phase-shifted control between the output cycloconveter and the input cycloconverter, commutation overlap period of the output cycloconverter, and polarity selection of the output filtering inductance current and the input voltage, the leakage inductance energy and the output filtering inductance current are naturally commutated, and surge voltage and surge current of the cycloconverters are overcome. The converters have such advantages as simple topology, two-stage power conversions(LFAC/HFAC/LFAC), bi-directional power flow, high frequency electrical isolation, good output waveforms, and strong ability to stabilize voltage. The converters lay key technical foundation on a new-type of regulated sinusoidal AC power supplies and electronic transformers. The correction and advancement of the converters are well verified by a principle test.%提出新颖的正激式高频环节交-交变换器电路结构和电路拓扑族,这类电路结构由输入周波变换器、高频变压器、输出周波变换器以及输入、输出滤波器构成,电路拓扑族包括全桥全波式等8种电路.深入研究了这类变换器的双极性移相控制策略和稳态原理,获得了外特性曲线.采用具有输出周波变换器与输入周波变换器之间移相、输出周波变换器换流重叠、输出滤波电感电流和输入电压极性选择的双极性移相控制策略,这类交-交变

  10. Chemical cross-linking of the urease complex from Helicobacter pylori and analysis by Fourier transform ion cyclotron resonance mass spectrometry and molecular modeling

    Science.gov (United States)

    Carlsohn, Elisabet; Ångström, Jonas; Emmett, Mark R.; Marshall, Alan G.; Nilsson, Carol L.

    2004-05-01

    Chemical cross-linking of proteins is a well-established method for structural mapping of small protein complexes. When combined with mass spectrometry, cross-linking can reveal protein topology and identify contact sites between the peptide surfaces. When applied to surface-exposed proteins from pathogenic organisms, the method can reveal structural details that are useful in vaccine design. In order to investigate the possibilities of applying cross-linking on larger protein complexes, we selected the urease enzyme from Helicobacter pylori as a model. This membrane-associated protein complex consists of two subunits: [alpha] (26.5 kDa) and [beta] (61.7 kDa). Three ([alpha][beta]) heterodimers form a trimeric ([alpha][beta])3 assembly which further associates into a unique dodecameric 1.1 MDa complex composed of four ([alpha][beta])3 units. Cross-linked peptides from trypsin-digested urease complex were analyzed by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and molecular modeling. Two potential cross-linked peptides (present in the cross-linked sample but undetectable in [alpha], [beta], and native complex) were assigned. Molecular modeling of urease [alpha][beta] complex and trimeric urease units ([alpha][beta])3 revealed a linkage site between the [alpha]-subunit and the [beta]-subunit, and an internal cross-linkage in the [beta]-subunit.

  11. Mutation frequencies of X-linked mental retardation genes in families from the EuroMRX consortium.

    Science.gov (United States)

    de Brouwer, Arjan P M; Yntema, Helger G; Kleefstra, Tjitske; Lugtenberg, Dorien; Oudakker, Astrid R; de Vries, Bert B A; van Bokhoven, Hans; Van Esch, Hilde; Frints, Suzanne G M; Froyen, Guy; Fryns, Jean-Pierre; Raynaud, Martine; Moizard, Marie-Pierre; Ronce, Nathalie; Bensalem, Anissa; Moraine, Claude; Poirier, Karine; Castelnau, Laetitia; Saillour, Yoann; Bienvenu, Thierry; Beldjord, Chérif; des Portes, Vincent; Chelly, Jamel; Turner, Gillian; Fullston, Tod; Gecz, Jozef; Kuss, Andreas W; Tzschach, Andreas; Jensen, Lars Riff; Lenzner, Steffen; Kalscheuer, Vera M; Ropers, Hans-Hilger; Hamel, Ben C J

    2007-02-01

    The EuroMRX family cohort consists of about 400 families with non-syndromic and 200 families with syndromic X-linked mental retardation (XLMR). After exclusion of Fragile X (Fra X) syndrome, probands from these families were tested for mutations in the coding sequence of 90 known and candidate XLMR genes. In total, 73 causative mutations were identified in 21 genes. For 42% of the families with obligate female carriers, the mental retardation phenotype could be explained by a mutation. There was no difference between families with (lod score >2) or without (lod score <2) significant linkage to the X chromosome. For families with two to five affected brothers (brother pair=BP families) only 17% of the MR could be explained. This is significantly lower (P=0.0067) than in families with obligate carrier females and indicates that the MR in about 40% (17/42) of the BP families is due to a single genetic defect on the X chromosome. The mutation frequency of XLMR genes in BP families is lower than can be expected on basis of the male to female ratio of patients with MR or observed recurrence risks. This might be explained by genetic risk factors on the X chromosome, resulting in a more complex etiology in a substantial portion of XLMR patients. The EuroMRX effort is the first attempt to unravel the molecular basis of cognitive dysfunction by large-scale approaches in a large patient cohort. Our results show that it is now possible to identify 42% of the genetic defects in non-syndromic and syndromic XLMR families with obligate female carriers.

  12. Optical Frequency Comb Fourier Transform Spectroscopy with Resolution Exceeding the Limit Set by the Optical Path Difference

    Science.gov (United States)

    Foltynowicz, Aleksandra; Rutkowski, Lucile; Johanssson, Alexandra C.; Khodabakhsh, Amir; Maslowski, Piotr; Kowzan, Grzegorz; Lee, Kevin; Fermann, Martin

    2015-06-01

    Fourier transform spectrometers (FTS) based on optical frequency combs (OFC) allow detection of broadband molecular spectra with high signal-to-noise ratios within acquisition times orders of magnitude shorter than traditional FTIRs based on thermal sources. Due to the pulsed nature of OFCs the interferogram consists of a series of bursts rather than a single burst at zero optical path difference (OPD). The comb mode structure can be resolved by acquiring multiple bursts, in both mechanical FTS systems and dual-comb spectroscopy. However, in all existing demonstrations the resolution was ultimately limited either by the maximum available OPD between the interferometer arms or by the total acquisition time enabled by the storage memory. We present a method that provides spectral resolution exceeding the limit set by the maximum OPD using an interferogram containing only a single burst. The method allows measurements of absorption lines narrower than the OPD-limited resolution without any influence of the instrumental lineshape function. We demonstrate this by measuring undistorted CO2 and CO absorption lines with linewidth narrower than the OPD-limited resolution using OFC-based mechanical FTS in the near- and mid-infrared wavelength ranges. The near-infrared system is based on an Er:fiber femtosecond laser locked to a high finesse cavity, while the mid-infrared system is based on a Tm:fiber-laser-pumped optical parametric oscillator coupled to a multi-pass cell. We show that the method allows acquisition of high-resolution molecular spectra with interferometer length orders of magnitude shorter than traditional FTIR. Mandon, J., G. Guelachvili, and N. Picque, Nat. Phot., 2009. 3(2): p. 99-102. Zeitouny, M., et al., Ann. Phys., 2013. 525(6): p. 437-442. Zolot, A.M., et al., Opt. Lett., 2012. 37(4): p. 638-640.

  13. Transforming p21 ras protein: flexibility in the major variable region linking the catalytic and membrane-anchoring domains

    DEFF Research Database (Denmark)

    Willumsen, B M; Papageorge, A G; Hubbert, N

    1985-01-01

    that is required for post-translational processing, membrane localization and transforming activity of the proteins. We have now used the viral oncogene (v-rasH) of Harvey sarcoma virus to study the major variable region by deleting or duplicating parts of the gene. Reducing this region to five amino acids...... or increasing it to 50 amino acids has relatively little effect on the capacity of the gene to induce morphological transformation of NIH 3T3 cells. Assays of GTP binding, GTPase and autophosphorylating activities of such mutant v-rasH-encoded proteins synthesized in bacteria indicated that the sequences...

  14. High-frequency transformation of a methylotrophic yeast, Candida boidinii, with autonomously replicating plasmids which are also functional in Saccharomyces cerevisiae.

    OpenAIRE

    Sakai, Y.; Goh, T K; Tani, Y.

    1993-01-01

    We have developed a transformation system which uses autonomous replicating plasmids for a methylotrophic yeast, Candida boidinii. Two autonomous replication sequences, CARS1 and CARS2, were newly cloned from the genome of C. boidinii. Plasmids having both a CARS fragment and the C. boidinii URA3 gene transformed C. boidinii ura3 cells to Ura+ phenotype at frequencies of up to 10(4) CFU/micrograms of DNA. From Southern blot analysis, CARS plasmids seemed to exist in polymeric forms as well as...

  15. Evaluation of agrobacterium-mediated transformation of Agaricus bisporus using a range of promoters linked to hygromycin resistance.

    Science.gov (United States)

    Burns, C; Leach, K M; Elliott, T J; Challen, M P; Foster, G D; Bailey, A

    2006-02-01

    There is interest in establishing genetic modification technologies for the cultivated mushroom Agaricus bisporus, both for improved crop characteristics and for molecular pharming. For these methods to be successful, it is necessary to establish a set of transformation systems that include robust and reliable vectors for gene manipulation. In this article, we report the evaluation of a series of promoters for driving expression of the Escherichia coli hph gene encoding hygromycin phosphotransferase. This was achieved using the Aspergillus nidulans gpdA and the A. bisporus gpdII and trp2 promoters. The Coprinus cinereus beta-tubulin promoter gave contrasting results depending on the size of promoter used, with a 393-bp region being effective, whereas the longer 453-bp fragment failed to yield any hygromycin-resistant transformants. The C. cinereus trp1 and the A. bisporus lcc1 promoters both failed to yield transformants. We also show that transformation efficiency may be improved by careful selection of both appropriate Agrobacterium strains, with AGL-1 yielding more than LBA1126 and by the choice of the binary vectors used to mobilize the DNA, with pCAMBIA vectors appearing to be more efficient than either pBIN19- or pGREEN-based systems.

  16. 主提升鼠笼式异步电动机变频改造%Frequency Transformation of Main Hoisting Squirrel-cage Asynchronous Motors

    Institute of Scientific and Technical Information of China (English)

    申昭

    2011-01-01

    主提升鼠笼式异步电动机变频调速系统的改造,其中以产生SPWM的HEF4752为控制核心,实现了鼠笼式异步电动机变频调速的闭环控制。%The transformation of the frequency controlling system of main hoisting squirrel-cage asynchronous motors realizes the closed-loop frequency control with the HEF4752 that produces SPWM as the core.

  17. Linking ground-water age and chemistry data along flow paths: Implications for trends and transformations of nitrate and pesticides

    Science.gov (United States)

    Tesoriero, Anthony J.; Saad, David A.; Burow, Karen R.; Frick, Elizabeth A.; Puckett, Larry J.; Barbash, Jack E.

    2007-10-01

    Tracer-based ground-water ages, along with the concentrations of pesticides, nitrogen species, and other redox-active constituents, were used to evaluate the trends and transformations of agricultural chemicals along flow paths in diverse hydrogeologic settings. A range of conditions affecting the transformation of nitrate and pesticides (e.g., thickness of unsaturated zone, redox conditions) was examined at study sites in Georgia, North Carolina, Wisconsin, and California. Deethylatrazine (DEA), a transformation product of atrazine, was typically present at concentrations higher than those of atrazine at study sites with thick unsaturated zones but not at sites with thin unsaturated zones. Furthermore, the fraction of atrazine plus DEA that was present as DEA did not increase as a function of ground-water age. These findings suggest that atrazine degradation occurs primarily in the unsaturated zone with little or no degradation in the saturated zone. Similar observations were also made for metolachlor and alachlor. The fraction of the initial nitrate concentration found as excess N 2 (N 2 derived from denitrification) increased with ground-water age only at the North Carolina site, where oxic conditions were generally limited to the top 5 m of saturated thickness. Historical trends in fluxes to ground water were evaluated by relating the times of recharge of ground-water samples, estimated using chlorofluorocarbon concentrations, with concentrations of the parent compound at the time of recharge, estimated by summing the molar concentrations of the parent compound and its transformation products in the age-dated sample. Using this approach, nitrate concentrations were estimated to have increased markedly from 1960 to the present at all study sites. Trends in concentrations of atrazine, metolachlor, alachlor, and their degradates were related to the timing of introduction and use of these compounds. Degradates, and to a lesser extent parent compounds, were detected

  18. [Analyzing moiré pattern spectra based on the mutual transform between signals' waveform in time domain and their spectra in frequency space].

    Science.gov (United States)

    Sun, Tao; Song, Yi-Zhong

    2013-11-01

    The mutual evolving processes of signals' waveforms and their spectra were numerically analyzed in time and frequency domains. The purpose was to research the essential relation between the signals' waveforms and their spectra. Then, the mutual transform principle was applied to analyze moiré pattern spectra, acquiring phase distribution information of the pattern. The rectangular window function was used to simulate the mutual transform between the impulse signal and direct-current waveform. Many rectangular window signals with deferent widths were obtained by changing the window width The unit impulse signal was obtained by changing the width down to zero, and the direct-current waveform obtained by changing the width up to +infinity. For smart, quick, and easy implementation of discrete Fourier transforms to rectangular pulses and obtain signals' spectra, a simple FFT system was worked out. With its calculating, the mutual evolving processes of signals' waveforms and their spectra were tracked deeply. All signals here were transformed with it. As the result, first, the spectra of rectangular window signals were in the form of sampling function [Sa(x) = sin(x)/x]. Second, with the change in the window's width, the waveform of Sa(x) changed. Third, when the width decreased, the waveform of Sa(x) extended, and vibrated more slowly. It changed into direct-current waveform when the width decreased to zero. Last, when the width increased, the waveform of Sa(x) shranked, and vibrated faster. It changed into impulse waveform when the width increased to +infinity. Signals' waveforms were in mutual transforms between the time and frequency domain. The transforming essence was considered as that the frequency component principle in Fourier series theory is reflected in the frequency domain. According to the principle of mutual transforms between signals' waveforms and their spectra, the first order spectrum of the moiré pattern was extracted out and normalized to a

  19. Synchrotron radiation Fourier-transform infrared and Raman microspectroscopy study showing an increased frequency of creatine inclusions in the rat hippocampal formation following pilocarpine-induced seizures

    OpenAIRE

    Dulinska, J.; Setkowicz, Z.; Janeczko, K.; C. SANDT; Dumas, P.; Uram, L.; Gzielo-Jurek, K.; Chwiej, J.

    2011-01-01

    In the present work, synchrotron radiation Fourier-transform infrared (SRFTIR) and Raman microspectroscopies were used to evaluate a possible role of creatine in the pathogenesis and progress of pilocarpine-evoked seizures and seizure-induced neurodegenerative changes in the rat hippocampal tissue. The main goal of this study was to identify creatine deposits within the examined brain area, to analyze their frequency in epileptic animals and naive controls and to examine correlations between ...

  20. On the determination of the dynamic properties of a transformer oil based ferrofluid in the frequency range 0.1-20 GHz

    Science.gov (United States)

    Fannin, P. C.; Vekas, L.; Marin, C. N.; Malaescu, I.

    2017-02-01

    Complex susceptibility measurements provide a unique and efficient means for the investigation and determination of the dynamic properties of magnetic fluids. In particular, measurement of the frequency, f(Hz), and field, H(kA/m), dependent, complex susceptibility, χ(ω, Η)= χ‧(ω, Η)-iχ″(ω, Η), of magnetic fluids has proven to be a valuable and reliable technique for investigating such properties. The experimental data presented here was obtained from measurements of a transformer oil based ferrofluid, with measurements being performed over the frequency range 0.1-20 GHz and polarising fields 0-168 kA/m. In the case of transformer oil magnetic fluids, the normal measurement emphasis has been on the investigation of their dielectric properties, including the effects which lightning may have on these properties. Little has been reported on the measurement of the corresponding magnetic susceptibility, χ(ω), of such fluids and in this paper we address this fact. Thus we consider it worthwhile, in the case of a transformer with magnetic fluid transformer oil, being affected as a result of a lightening occurrence, to have knowledge of the fluids dynamic properties, at the microwave frequencies. In the process of determining the sample susceptibility profiles, it was found that the peak value of the χ″(ω) component, was approximately constant over the frequency range 2.4-6.3 GHz. From this it was determined that the fluid was effectively operating as a wideband absorber over a bandwidth of 3.9 GHz.

  1. Impact of turbulent phase noise on frequency transfer with asymmetric two-way ground-satellite coherent optical links

    Science.gov (United States)

    Robert, Clélia; Conan, Jean-Marc; Wolf, Peter

    2016-06-01

    Bidirectional ground-satellite laser links suffer from turbulence-induced scintillation and phase distortion. We study how turbulence impacts on coherent detection capacity and on the associated phase noise that restricts clock transfer precision. We evaluate the capacity to obtain a two-way cancellation of atmospheric effects despite the asymmetry between up and down link that limits the link reciprocity. For ground-satellite links, the asymmetry is induced by point-ahead angle and possibly the use, for the ground terminal, of different transceiver diameters, in reception and emission. The quantitative analysis is obtained thanks to refined end- to-end simulations under realistic turbulence and wind conditions as well as satellite cinematic. These temporally resolved simulations allow characterizing the coherent detection in terms of time series of heterodyne efficiency for different system parameters. We show that Tip/Tilt correction on ground is mandatory at reception for the down link and as a pre-compensation of the up link. Good correlation between up and down phase noise is obtained even with asymmetric apertures of the ground transceiver and in spite of pointing ahead angle. The reduction to less than 1 rad2 of the two-way differential phase noise is very promising for clock comparisons.

  2. Frequency scaling of slant-path atmospheric attenuation in the absence of rain for millimeter-wave links

    Science.gov (United States)

    Lucas-Vegas, María. José; Riera, José Manuel

    2016-11-01

    Broadband satellite communications systems, either used for broadcast or fixed satellite services, have grown continuously in recent years. This has led to the use of higher frequency bands, from the Ku (14/11 GHz) to the Ka band (30/20 GHz) in the last decade, and with the expectation of using the Q/V band (50/40 GHz) and even the W band (75-110 GHz) in the future. As frequency increases, radio wave propagation effects in the slant-path within the troposphere are becoming more and more relevant. The objective of this research is the proposal of frequency scaling approximations for the total attenuation in the absence of rain, a condition that occurs during the highest percentages of time, usually more than 95% in temperate climates. There is a strong relationship between total attenuation at different frequencies, as it arises from the same physical phenomena, namely, the presence of oxygen, water vapor, and clouds in the slant path. This strong relationship allows frequency scaling estimations to be proposed. In particular, polynomials for instantaneous frequency scaling of total attenuation under these conditions have been calculated for a set of frequencies in the range 10-100 GHz, based on atmospheric profiles of 60 sites from all over the world and physical models of attenuation. Global polynomials are provided for the 72 combinations of nine significant frequencies, which can be used to estimate attenuation at a frequency band from its known value at a different one. Refined expressions have also been calculated for different climatic zones, providing more precise estimations.

  3. 1 Gbps full-duplex links for ultra-dense-WDM 6.25 GHz frequency slots in optical metro-access networks.

    Science.gov (United States)

    Altabas, Jose A; Izquierdo, David; Lazaro, Jose A; Lerin, Adolfo; Sotelo, Felix; Garces, Ignacio

    2016-01-11

    1 Gbps full-duplex optical links for 6.25 GHz ultra dense WDM frequency slots are demonstrated and optimized for cost-effective metro-access networks. The OLT-ONU downlinks are based on 1 Gbps Nyquist-DPSK using MZM and single-detector heterodyne reception obtaining a sensitivity of -52 dBm. The ONU-OLT uplinks are based on 1 Gbps NRZ-DPSK by directly phase modulated DFB and also single-detector heterodyne reception obtaining same sensitivity of -52 dBm. The power budget of full-duplex link is 43 dB. These proposed links can provide service to 16 (32) users at each 100 (200) GHz WDM channel.

  4. 归一化窗S变换和TT变换联合时频滤波%NWST and TT-transform joint time-frequency filtering

    Institute of Scientific and Technical Information of China (English)

    王娟; 何怡刚; 方葛丰; 樊晓腾

    2012-01-01

    Based on the characteristics of radar signal and principle of the normalized window S transform( NWST) and TT-transform, this paper proposed a new two-dimensional time-frequency filtering method for radar echo signal. First,this method used time-frequency filtering based on NWST to filter out high frequency noise and random noise radar signal. Then,it used TT-transform to filter out low frequency noise. The experimental results show that, compared to traditional filter, the filter operator of the proposed method synchronously changes with the time and frequency to overcome the shortcomings of traditional method by the use of conditions. At the same time, this method can effectively filter out the noise while retenting of the original signal characteristics, so that enhance detection and recognition ability.%基于雷达信号特性及归一化窗S变换与TT变换原理,提出一种新的雷达回波信号二维时频滤波方法.通过对雷达信号进行归一化窗S变换时频滤波,滤除高频杂波和随机噪声;再利用TT变换滤除低频杂波.实验结果表明,相较于传统滤波,所提方法的滤波算子随时间及频率同步变化,克服了传统方法受使用条件限制的缺点;有效滤除杂波的同时保留原信号特征,增强了检测及识别能力.

  5. Decoupling of mechanical systems based on in-situ frequency response functions: The link-preserving, decoupling method

    Science.gov (United States)

    Keersmaekers, Laurent; Mertens, Luc; Penne, Rudi; Guillaume, Patrick; Steenackers, Gunther

    2015-06-01

    Mechanical structures often consist of active and passive parts, the former containing the sources, the latter the transfer paths and the targets. The active and passive parts are connected to each other by means of links. In this paper, an innovative theoretical model has been developed to achieve the mathematical decoupling of such structures without disassembling the substructures, when the links connecting the structures are resilient enough. This procedure is required to identify components causing a specific Noise, Vibration and Harsh-ness (NVH) problem. The links are regarded as a parallel connection of springs and dampers, ignoring some physical properties. However, the new procedure will provide a powerful construction in which different link models can be investigated. Therefore, this procedure will be called the Link-Preserving, Decoupling Method (LPD method). The absence of a time-consuming physical decoupling procedure distinguishes the LPD method from all known methods such as the classical TPA method. The LPD method is validated by two numerical simulations using linear and nonlinear lumped parameter models and by an experimental case study.

  6. Changes in magnitude and frequency of heavy precipitation across China and its potential links to summer temperature

    Science.gov (United States)

    Gu, Xihui; Zhang, Qiang; Singh, Vijay P.; Shi, Peijun

    2017-04-01

    Changes in the magnitude, frequency and timing of heavy precipitation are closely related to the occurrence of floods and droughts, which hold a great deal of significance for management of agricultural irrigation and water resources. Records of daily precipitation and temperature from 728 stations across China were used to assess changes in the magnitude, frequency and timing of heavy precipitation using the Peak-over-Threshold (POT) with 95th percentile as the threshold. Because of the continuous nature of the magnitude and timing of heavy precipitation, the ;change point; method and the modified Mann-Kendall trend test method were used to detect change points (CPs) and slowly-varying changes, respectively. In addition, the segmented regression and Poisson regression methods were used to detect CPs and temporal trends in the frequency of heavy precipitation, respectively, with consideration of the count nature of the data. The results showed that 55% and 36% of the stations had CPs in mean and/or variance of the magnitude and timing, respectively, while the percentage is only 5.8% in the frequency. However, while there is limited evidence of significant trends in the magnitude and timing, strong evidence points to a significant increasing frequency in most regions of China. These changes may be partly explained by changes in summer temperature. Examination of the summer surface temperature records suggests that the areas, where the frequency of heavy precipitation has a significant increase, are also mostly characterized by significant increasing temperature. In addition, trends of the frequency vary between the periods before and after the turn point (TP) of summer temperature trends, especially in northern China where both the summer temperature and the frequency have shifted significantly decreasing trends to significantly increasing trends. A possible interpretation of these findings is that storms tend to be more frequent without significant changes in water

  7. Analysis of a modular generator for high-voltage, high-frequency pulsed applications, using low voltage semiconductors (series connected step-up (1:10) transformers

    Science.gov (United States)

    Redondo, L. M.; Fernando Silva, J.; Margato, E.

    2007-03-01

    This article discusses the operation of a modular generator topology, which has been developed for high-frequency (kHz), high-voltage (kV) pulsed applications. The proposed generator uses individual modules, each one consisting of a pulse circuit based on a modified forward converter, which takes advantage of the required low duty cycle to operate with a low voltage clamp reset circuit for the step-up transformer. This reduces the maximum voltage on the semiconductor devices of both primary and secondary transformer sides. The secondary winding of each step-up transformer is series connected, delivering a fraction of the total voltage. Each individual pulsed module is supplied via an isolation transformer. The assembled modular laboratorial prototype, with three 5kV modules, 800V semiconductor switches, and 1:10 step-up transformers, has 80% efficiency, and is capable of delivering, into resistive loads, -15kV/1A pulses with 5μs width, 10kHz repetition rate, with less than 1μs pulse rise time. Experimental results for resistive loads are presented and discussed.

  8. Analysis of a modular generator for high-voltage, high-frequency pulsed applications, using low voltage semiconductors (series connected step-up (1:10) transformers.

    Science.gov (United States)

    Redondo, L M; Fernando Silva, J; Margato, E

    2007-03-01

    This article discusses the operation of a modular generator topology, which has been developed for high-frequency (kHz), high-voltage (kV) pulsed applications. The proposed generator uses individual modules, each one consisting of a pulse circuit based on a modified forward converter, which takes advantage of the required low duty cycle to operate with a low voltage clamp reset circuit for the step-up transformer. This reduces the maximum voltage on the semiconductor devices of both primary and secondary transformer sides. The secondary winding of each step-up transformer is series connected, delivering a fraction of the total voltage. Each individual pulsed module is supplied via an isolation transformer. The assembled modular laboratorial prototype, with three 5 kV modules, 800 V semiconductor switches, and 1:10 step-up transformers, has 80% efficiency, and is capable of delivering, into resistive loads, -15 kV1 A pulses with 5 micros width, 10 kHz repetition rate, with less than 1 micros pulse rise time. Experimental results for resistive loads are presented and discussed.

  9. Experimental Investigation Related To Some Predicted Results Of Reliable High Frequency Radio Communication Links Between Benghazi-Libya And Cairo-Egypt.

    Directory of Open Access Journals (Sweden)

    Mohamed Yousef Ahmed Abou-Hussein

    2014-01-01

    Full Text Available In this study, the central radio propagation laboratory (CRPL method of ionospheric prediction of the National Bureau of Standards (NBS in U.S.A was used in practical calculations of the optimal working frequencies for reliable high frequency (HF radio communication links between Benghazi-Libya and Cairo-Egypt. The results were drawn in the form of curves by using the computer. The computer was used to measure the received signal level variation of frequencies 11.980 MHz, 11.785 MHz which were transmitted with a power of 250 KW, 100 KW respectively from the Egypt Arabic Republic Broadcasting station in Cairo city, directed to the North Africa and South Europe regions. The measurements were taken during daytime's for winter (December, January& February and summer (June, July & August seasons.

  10. Global gene expression profiling of brown to white adipose tissue transformation in sheep reveals novel transcriptional components linked to adipose remodeling.

    Science.gov (United States)

    Basse, Astrid L; Dixen, Karen; Yadav, Rachita; Tygesen, Malin P; Qvortrup, Klaus; Kristiansen, Karsten; Quistorff, Bjørn; Gupta, Ramneek; Wang, Jun; Hansen, Jacob B

    2015-03-19

    Large mammals are capable of thermoregulation shortly after birth due to the presence of brown adipose tissue (BAT). The majority of BAT disappears after birth and is replaced by white adipose tissue (WAT). We analyzed the postnatal transformation of adipose in sheep with a time course study of the perirenal adipose depot. We observed changes in tissue morphology, gene expression and metabolism within the first two weeks of postnatal life consistent with the expected transition from BAT to WAT. The transformation was characterized by massively decreased mitochondrial abundance and down-regulation of gene expression related to mitochondrial function and oxidative phosphorylation. Global gene expression profiling demonstrated that the time points grouped into three phases: a brown adipose phase, a transition phase and a white adipose phase. Between the brown adipose and the transition phase 170 genes were differentially expressed, and 717 genes were differentially expressed between the transition and the white adipose phase. Thirty-eight genes were shared among the two sets of differentially expressed genes. We identified a number of regulated transcription factors, including NR1H3, MYC, KLF4, ESR1, RELA and BCL6, which were linked to the overall changes in gene expression during the adipose tissue remodeling. Finally, the perirenal adipose tissue expressed both brown and brite/beige adipocyte marker genes at birth, the expression of which changed substantially over time. Using global gene expression profiling of the postnatal BAT to WAT transformation in sheep, we provide novel insight into adipose tissue plasticity in a large mammal, including identification of novel transcriptional components linked to adipose tissue remodeling. Moreover, our data set provides a useful resource for further studies in adipose tissue plasticity.

  11. Direct estimation of the recombination frequency between the RB1 gene and two closely linked microsatellites using sperm typing.

    Science.gov (United States)

    Girardet, A; Lien, S; Leeflang, E P; Beaufrère, L; Tuffery, S; Munier, F; Arnheim, N; Claustres, M; Pellestor, F

    1999-01-01

    In this study, single sperm typing has been used for high-resolution recombination analysis between the retinoblastoma gene and two closely linked extragenic microsatellites (D13S284 and D13S1307). The analysis of 1198 single sperm from three donors allowed the determination of recombination fractions between RB1.20 and D13S284 and RB1.20 and D13S1307 of 0.022 and 0.033, respectively. These results show that RB1 gene and the two microsatellites are closely linked, which validates their potential use in indirect genetic diagnosis of retinoblastoma.

  12. Adapted wavelet transform improves time-frequency representations: a study of auditory elicited P300-like event-related potentials in rats

    Science.gov (United States)

    Richard, Nelly; Laursen, Bettina; Grupe, Morten; Drewes, Asbjørn M.; Graversen, Carina; Sørensen, Helge B. D.; Bastlund, Jesper F.

    2017-04-01

    Objective. Active auditory oddball paradigms are simple tone discrimination tasks used to study the P300 deflection of event-related potentials (ERPs). These ERPs may be quantified by time-frequency analysis. As auditory stimuli cause early high frequency and late low frequency ERP oscillations, the continuous wavelet transform (CWT) is often chosen for decomposition due to its multi-resolution properties. However, as the conventional CWT traditionally applies only one mother wavelet to represent the entire spectrum, the time-frequency resolution is not optimal across all scales. To account for this, we developed and validated a novel method specifically refined to analyse P300-like ERPs in rats. Approach. An adapted CWT (aCWT) was implemented to preserve high time-frequency resolution across all scales by commissioning of multiple wavelets operating at different scales. First, decomposition of simulated ERPs was illustrated using the classical CWT and the aCWT. Next, the two methods were applied to EEG recordings obtained from prefrontal cortex in rats performing a two-tone auditory discrimination task. Main results. While only early ERP frequency changes between responses to target and non-target tones were detected by the CWT, both early and late changes were successfully described with strong accuracy by the aCWT in rat ERPs. Increased frontal gamma power and phase synchrony was observed particularly within theta and gamma frequency bands during deviant tones. Significance. The study suggests superior performance of the aCWT over the CWT in terms of detailed quantification of time-frequency properties of ERPs. Our methodological investigation indicates that accurate and complete assessment of time-frequency components of short-time neural signals is feasible with the novel analysis approach which may be advantageous for characterisation of several types of evoked potentials in particularly rodents.

  13. Potassium chloride and rare earth elements improve plant growth and increase the frequency of the Agrobacterium tumefaciens-mediated plant transformation.

    Science.gov (United States)

    Boyko, Alex; Matsuoka, Aki; Kovalchuk, Igor

    2011-04-01

    Plant transformation efficiency depends on the ability of the transgene to successfully interact with plant host factors. Our previous work and the work of others showed that manipulation of the activity of host factors allows for increased frequency of transformation. Recently we reported that exposure of tobacco plants to increased concentrations of ammonium nitrate increases the frequency of both homologous recombination and plant transgenesis. Here we tested the influence of KCl and salts of rare earth elements, Ce and La on the efficiency of Agrobacterium-mediated plant transformation. We found that exposure to KCl, CeCl(3) and LaCl(3) leads to an increase in recombination frequency in Arabidopsis and tobacco. Plants grown in the presence of CeCl(3) and LaCl(3) had higher biomass, longer roots and greater root number. Analysis of transformation efficiency showed that exposure of tobacco plants to 50 mM KCl resulted in ~6.0-fold increase in the number of regenerated calli and transgenic plants as compared to control plants. Exposure to various concentrations of CeCl(3) showed a maximum increase of ~3.0-fold in both the number of calli and transgenic plants. Segregation analysis showed that exposure to KCl and cerium (III) chloride leads to more frequent integrations of the transgene at a single locus. Analysis of transgene intactness showed better preservation of right T-DNA border during transgene integration. Our data suggest that KCl and CeCl(3) can be effectively used to improve quantity and quality of transgene integrations.

  14. Mutation frequencies of X-linked mental retardation genes in families from the EuroMRX consortium.

    NARCIS (Netherlands)

    Brouwer, A.P.M. de; Yntema, H.G.; Kleefstra, T.; Lugtenberg, D.; Oudakker, A.R.; Vries, B. de; Bokhoven, J.H.L.M. van; Esch, H. van; Frints, S.G.; Froyen, G.; Fryns, J.P.; Raynaud, M.; Moizard, M.P.; Ronce, N.; Bensalem, A.; Moraine, C.; Poirier, K.; Castelnau, L.; Saillour, Y.; Bienvenu, T.; Beldjord, C.; Portes, V. des; Chelly, J.; Turner, G.; Fullston, T.; Gecz, J.; Kuss, A.W.; Tzschach, A.; Jensen, L.R.; Lenzner, S.; Kalscheuer, V.M.M.; Ropers, H.H.; Hamel, B.C.J.

    2007-01-01

    The EuroMRX family cohort consists of about 400 families with non-syndromic and 200 families with syndromic X-linked mental retardation (XLMR). After exclusion of Fragile X (Fra X) syndrome, probands from these families were tested for mutations in the coding sequence of 90 known and candidate XLMR

  15. Transformation of metal-organic framework to polymer gel by cross-linking the organic ligands preorganized in metal-organic framework.

    Science.gov (United States)

    Ishiwata, Takumi; Furukawa, Yuki; Sugikawa, Kouta; Kokado, Kenta; Sada, Kazuki

    2013-04-10

    Until now, seamless fusion of metal-organic frameworks (MOFs) and covalently cross-linked polymer gels (PG) at molecular level has been extremely rare, since these two matters have been regarded as opposite, that is, hard versus soft. In this report, we demonstrate transformation of cubic MOF crystals to PG via inner cross-linking of the organic linkers in the void space of MOF, followed by decomposition of the metal coordination. The obtained PG behaved as a polyelectrolyte gel, indicating the high content of ionic groups inside. Metal ions were well adsorbed in the PG due to its densely packed carboxylate groups. A chimera-type hybrid material consisting of MOF and PG was obtained by partial hydrolysis of resulting cross-linked MOF. The shape of resulting PG network well reflected the crystal structure of MOF employed as a template. Our results will connect the two different network materials that have been ever studied in the two different fields to provide new soft and hard hybrid materials, and the unique copolymerization in the large void space of the MOF will open a new horizon toward "ideal network polymers" never prepared before now.

  16. The influence of task frequency and force direction on psychophysically acceptable forces in the context of the biomechanically weakest links.

    Science.gov (United States)

    Cudlip, Alan C; Fischer, Steven L; Wells, Richard; Dickerson, Clark R

    2013-06-01

    This study examined the influence of frequency and direction of force application on psychophysically acceptable forces for simulated work tasks. Fifteen male participants exerted psychophysically acceptable forces on a force transducer at 1, 3, or 5 repetitions per minute by performing both a downward press and a pull toward the body. These exertions were shown previously to be strength and balance limited, respectively. Workers chose acceptable forces at a lower percentage of their maximum voluntary force capacity during downward (strength-limited) exertions than during pulling (balance-limited) exertions at all frequencies (4% to 11%, P = .035). Frequency modulated acceptable hand force only during downward exertions, where forces at five repetitions per minute were 13% less (P = .005) than those at one exertion per minute. This study provides insight into the relationship between biomechanically limiting factors and the selection of acceptable forces for unilateral manual tasks.

  17. Research on Feature Extraction of Composite Pseudocode Phase Modulation-Carrier Frequency Modulation Signal Based on PWD Transform

    Institute of Scientific and Technical Information of China (English)

    LI Ming-zi; ZHAO Hui-chang

    2008-01-01

    The identification features of composite pseudocode phase modulation and carry frequency modulation signal in-clude pseudocode and modulation frequency. In this paper, PWD is used to extract these features. First, the feature of pseudocode is extracted using the amplitude output of PWD and the correlation filter technology. Then the feature of fre-quency modulation is extracted by way of PWD analysis on the signal processed by anti-phase operation according to the extracted feature of pseudo code, i.e. position information of changed abruptly point of phase. The simulation result shows that both the features of frequency modulation and phase change position caused by the pseudocode phase modula-tion can be extracted effectively for SNR = 3 dB.

  18. Spatial Carrier Bi-frequency Fourier Transform Profilometry for the 3-D Shape Measurement of Object with Discontinuous Height Steps

    Institute of Scientific and Technical Information of China (English)

    ZHONG Jingang; DI Hongwei; ZHANG Yonglin

    2000-01-01

    The combination of shearing interferometer, Fourier-transform profilometry, phase unwrapping by lookup table method has resulted in a new and more powerful method of measuring surface profile. The technique permits the three-dimensional shape measurement of objects that have discontinuous height steps. Experimental results have demonstrated the validity of the principle.

  19. Sonication, Vacuum Infiltration and Thiol Compounds Enhance the Agrobacterium-Mediated Transformation Frequency of Withania somnifera (L.) Dunal.

    Science.gov (United States)

    Sivanandhan, Ganeshan; Kapil Dev, Gnajothi; Theboral, Jeevaraj; Selvaraj, Natesan; Ganapathi, Andy; Manickavasagam, Markandan

    2015-01-01

    In the present study, we have established a stable transformation protocol via Agrobacterium tumafacines for the pharmaceutically important Withania somnifera. Six day-old nodal explants were used for 3 day co-cultivation with Agrobacterium tumefaciens strain LBA4404 harbouring the vector pCAMIBA2301. Among the different injury treatments, sonication, vacuum infiltration and their combination treatments tested, a vacuum infiltration for 10 min followed by sonication for 10 sec with A. tumefaciens led to a higher transient GUS expression (84% explants expressing GUS at regenerating sites). In order to improve gene integration, thiol compounds were added to co-cultivation medium. A combined treatment of L-Cys at 100 mg/l, STS at 125 mg/l, DTT at 75 mg/l resulted in a higher GUS expression (90%) in the nodal explants. After 3 days of co-cultivation, the explants were subjected to three selection cycles with increasing concentrations of kanamycin [100 to 115 mg/l]. The integration and expression of gusA gene in T0 and T1 transgenic plants were confirmed by polymerase chain reaction (PCR), and Southern blott analysis. These transformed plants (T0 and T1) were fertile and morphologically normal. From the present investigation, we have achieved a higher transformation efficiency of (10%). Withanolides (withanolide A, withanolide B, withanone and withaferin A) contents of transformed plants (T0 and T1) were marginally higher than control plants.

  20. Sonication, Vacuum Infiltration and Thiol Compounds Enhance the Agrobacterium-Mediated Transformation Frequency of Withania somnifera (L. Dunal.

    Directory of Open Access Journals (Sweden)

    Ganeshan Sivanandhan

    Full Text Available In the present study, we have established a stable transformation protocol via Agrobacterium tumafacines for the pharmaceutically important Withania somnifera. Six day-old nodal explants were used for 3 day co-cultivation with Agrobacterium tumefaciens strain LBA4404 harbouring the vector pCAMIBA2301. Among the different injury treatments, sonication, vacuum infiltration and their combination treatments tested, a vacuum infiltration for 10 min followed by sonication for 10 sec with A. tumefaciens led to a higher transient GUS expression (84% explants expressing GUS at regenerating sites. In order to improve gene integration, thiol compounds were added to co-cultivation medium. A combined treatment of L-Cys at 100 mg/l, STS at 125 mg/l, DTT at 75 mg/l resulted in a higher GUS expression (90% in the nodal explants. After 3 days of co-cultivation, the explants were subjected to three selection cycles with increasing concentrations of kanamycin [100 to 115 mg/l]. The integration and expression of gusA gene in T0 and T1 transgenic plants were confirmed by polymerase chain reaction (PCR, and Southern blott analysis. These transformed plants (T0 and T1 were fertile and morphologically normal. From the present investigation, we have achieved a higher transformation efficiency of (10%. Withanolides (withanolide A, withanolide B, withanone and withaferin A contents of transformed plants (T0 and T1 were marginally higher than control plants.

  1. Linking Organic Matter Deposition And Iron Mineral Transformations to Groundwater Arsenic Levels in the Mekong Delta, Cambodia

    Energy Technology Data Exchange (ETDEWEB)

    Quicksall, A.N.; Bostick, B.C.; Sampson, M.L.

    2009-05-21

    Enriched As in drinking water wells in south and Southeast Asia has increased the risk of cancer for nearly 100 million people. This enrichment is generally attributed to the reductive dissolution of Fe oxides; however, the complex expression of As enrichment in these areas is not yet well understood. Here, the coupled sedimentological and geochemical factors that contribute to the extent and spatial distribution of groundwater As concentrations in the Mekong River delta, Cambodia in an avulsed scroll bar sequence are examined. X-Ray absorption spectroscopy (XAS) was used to determine Fe and As speciation in redox preserved sediment collected from drilled cores. Dissolved As, Fe and S solution concentrations in existing and newly drilled wells (cores) differed considerably depending on their source sedimentology. The rapid burial of organic matter in the scroll bar sequence facilitated the development of extensive Fe-reducing conditions, and As release into the aquifer. In older features organic C levels are high enough to sustain extensive Fe reduction and provide ample SO{sub 4} which is reduced to sulfide. This S reduction impacts As levels; As is sequestered in sulfide minerals outside of the scrollbar sequence, decreasing pore water concentrations. In contrast, As is depleted in sediments from the scroll sequence, and associated with elevated pore water aqueous concentrations. The concentration and form of organic C in the scrollbar sequence is related to depositional environment, and can facilitate Fe and S mineral transformations, distinct sedimentary environments explain a portion of the inherent heterogeneity of aquifer As concentrations.

  2. PERFORMANCE ANALYSIS OF DISCRETE WAVELET TRANSFORM BASED MULTIPLE INPUT MULTIPLE OUTPUT ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING SYSTEM FOR DIFFERENT WAVELETS IN DIFFERENT CHANNEL ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    HariprasadNagarajan

    2013-01-01

    Full Text Available Multiple Input Multiple Output (MIMO and Orthogonal Frequency Division Multiplexing (OFDM are the two assuring technologies that offers high data rate as required for the 4G wireless systems. Conventionally OFDM is Fast Fourier Transform (FFT based system. It uses IFFT (Inverse FFT blocks in the transmitter and FFT blocks in the receiver. OFDM combined with MIMO gives increased throughput and better system performance and hence FFT based MIMO OFDM systems are widely used in 4G wireless schemes. Recent researches shows that replacing the FFT with Discrete Wavelet Transform (DWT the system performance can be further improved. This leads to a new scenario DWT based MIMO OFDM system. In this study one such system is simulated and the Bit Error Rate (BER performance of the system is analysed for the different types of wavelets under different channel environments.

  3. High-Frequency Link Inverter for Fuel Cells Based on Multiple-Carrier PWM (to continue)

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    C. Operation of a PWM Cycloconverter The concepts in Section Ⅱ-B, present a progression of solutions to known design difficulties. To incorporate these benefits and eliminate the redundant conversion step shown in Fig. 6, we propose the PWM cycloconverter shown in Fig. 7. It will be shown in Section Ⅲ. that the conventional PWM inverter can be unified through a multiple-carrier PWM framework. The control concept introduced is extended to demonstrate that multiple-carrier PWM methods lead to HF link inverters that are nearly as simple to control as conventional PWM inverters.

  4. Providing hydrogen maser timing stability to orbiting VLBI radio telescope observations by post-measurement compensation of linked frequency standard imperfections

    Science.gov (United States)

    Springett, James C.

    1994-01-01

    Orbiting VLBI (OVLBI) astronomical observations are based upon measurements acquired simultaneously from ground-based and earth-orbiting radio telescopes. By the mid-1990s, two orbiting VLBI observatories, Russia's Radioastron and Japan's VSOP, will augment the worldwide VLBI network, providing baselines to earth radio telescopes as large as 80,000 km. The challenge for OVLBI is to effectuate space to ground radio telescope data cross-correlation (the observation) to a level of integrity currently achieved between ground radio telescopes. VLBI radio telescopes require ultrastable frequency and timing references in order that long term observations may be made without serious cross-correlation loss due to frequency source drift and phase noise. For this reason, such instruments make use of hydrogen maser frequency standards. Unfortunately, space-qualified hydrogen maser oscillators are currently not available for use on OVLBI satellites. Thus, the necessary long-term stability needed by the orbiting radio telescope may only be obtained by microwave uplinking a ground-based hydrogen maser derived frequency to the satellite. Although the idea of uplinking the frequency standard intrinsically seems simple, there are many 'contaminations' which degrade both the long and short term stability of the transmitted reference. Factors which corrupt frequency and timing accuracy include additive radio and electronic circuit thermal noise, slow or systematic phase migration due to changes of electronic circuit temporal operating conditions (especially temperature), ionosphere and troposphere induced scintillations, residual Doppler-incited components, and microwave signal multipath propagation. What is important, though, is to realize that ultimate stability does not have to be achieved in real-time. Instead, information needed to produce a high degree of coherence in the subsequent cross-correlation operation may be derived from a two-way coherent radio link, recorded and later

  5. [Effect of Low-Intensity 900 MHz Frequency Electromagnetic Radiation on Rat Brain Enzyme Activities Linked to Energy Metabolism].

    Science.gov (United States)

    Petrosyan, M S; Nersesova, L S; Gazaryants, M G; Meliksetyan, G O; Malakyan, M G; Bajinyan, S A; Akopian, J I

    2015-01-01

    The research deals with the effect of low-intensity 900 MHz frequency electromagnetic radiation (EMR), power density 25 μW/cm2, on the following rat brain and blood serum enzyme activities: creatine kinase (CK), playing a central role in the process of storing and distributing the cell energy, as well as alanine aminotransferase (ALT) and aspartate aminotransferase (AST) that play a key role in providing the conjunction of carbohydrate and amino acid metabolism. The comparative analysis of the changes in the enzyme activity studied at different times following the two-hour single, as well as fractional, radiation equivalent of the total time showed that the most radiosensitive enzyme is the brain creatine kinase, which may then be recommended as a marker of the radio frequency radiation impact. According to the analysis of the changing dynamics of the CK, ALT and AST activity level, with time these changes acquire the adaptive character and are directed to compensate the damaged cell energy metabolism.

  6. OTDM-to-WDM Conversion Based on Time-to-Frequency Mapping by Time-Domain Optical Fourier Transformation

    DEFF Research Database (Denmark)

    Palushani, Evarist; Mulvad, Hans Christian Hansen; Galili, Michael

    2012-01-01

    a dispersive medium followed by phase modulation; the latter being achieved by a four-wave mixing process with linearly chirped pump pulses. Both numerical and experimental investigations of the OTDM-to-WDM conversion technique are carried out. Experimental validations are performed on......This paper reports on the utilization of the timedomain optical Fourier transformation (OFT) technique for serial-to-parallel conversion of optical time division multiplexed (OTDM) data tributaries into dense wavelength division multiplexed (DWDM) channels. The OFT is implemented by using...

  7. Molecular genetics of X chromosome-linked color vision among populations of African and Japanese ancestry: High frequency of a shortened red pigment gene among Afro-Americans

    Energy Technology Data Exchange (ETDEWEB)

    Joergensen, A.L.; Deeb, S.S.; Motulsky, A.G. (Univ. of Washington, Seattle (USA))

    1990-09-01

    Red-green color vision in humans is mediated by the X chromosome-linked highly homologous red and green pigment genes. Color vision defects are caused by deletions and fusions involving these genes. However, the authors found the frequency of molecular abnormalities among Caucasians to be twice as high as that of phenotypic color vision defects. Among Japanese the frequency of phenotypic and molecular color vision defects was similar. Among Afro-Americans, molecular defects were at least five times more frequent than phenotypic color vision defects. In addition, 35% of Afro-Americans, 2% of Japanese, and <1% of Caucasians had a shortened red pigment gene not associated with phenotpyic color vision defects. This gene lacked 1.9 kilobases in its first intron and had the identical size as the green pigment gene from which it presumably originated by gene conversion in an ancestral African population. This gene and the closely linked glucose-6-phosphate dehydrogenase A{sup +} variant were in linkage equilibrium. A model for the evolutionary origin of the color vision pigment genes in higher primates is portrayed.

  8. Assessment of periodic sub-diurnal Earth rotation variations at tidal frequencies through transformation of VLBI normal equation systems

    Science.gov (United States)

    Artz, Thomas; Tesmer Née Böckmann, Sarah; Nothnagel, Axel

    2011-09-01

    We present an empirical model for periodic variations of diurnal and sub-diurnal Earth rotation parameters (ERPs) that was derived based on the transformation of normal equation (NEQ) systems of Very Long Baseline Interferometry (VLBI) observing sessions. NEQ systems that contain highly resolved polar motion and UT1-TAI with a temporal resolution of 15 min were generated and then transformed to the coefficients of the tidal ERP model to be solved for. To investigate the quality of this model, comparisons with empirical models from the Global Positioning System (GPS), another VLBI model and the model adopted by the conventions of the International Earth Rotation and Reference Systems Service (IERS) were performed. The absolute coefficients of these models agree almost completely within 7.5 μ as in polar motion and 0.5 μ s in UT1-TAI. Several bigger differences exist, which are discussed in this paper. To be able to compare the model estimates with results of the continuous VLBI campaigns, where signals with periods of 8 and 6 h were detected, terms in the ter- and quarter-diurnal band were included in the tidal ERP model. Unfortunately, almost no common features with the results of continuous VLBI campaigns or ERP predictions in these tidal bands can be seen.

  9. Motor dysfunction in the tottering mouse is linked to cerebellar spontaneous low frequency oscillations revealed by flavoprotein autofluorescence optical imaging

    Science.gov (United States)

    Chen, Gang; Popa, Laurentiu S.; Wang, Xinming; Gao, Wangcai; Barnes, Justin; Hendrix, Claudia M.; Hess, Ellen J.; Ebner, Timothy J.

    2009-02-01

    Flavoprotein autofluorescence optical imaging is developing into a powerful research tool to study neural activity, particularly in vivo. In this study we used this imaging technique to investigate the neuronal mechanism underlying the episodic movement disorder that is characteristic of the tottering (tg) mouse, a model of episodic ataxia type 2. Both EA2 and the tg mouse are caused by mutations in the gene encoding Cav2.1 (P/Q-type) voltage-gated Ca2+ channels. These mutations result in a reduction in P/Q Ca2+ channel function. Both EA2 patients and tg mice have a characteristic phenotype consisting of transient motor attacks triggered by stress, caffeine or ethanol. The neural events underlying these episodes of dystonia are unknown. Flavoprotein autofluorescence optical imaging revealed spontaneous, transient, low frequency oscillations in the cerebellar cortex of the tg mouse. Lasting from 30 - 120 minutes, the oscillations originate in one area then spread to surrounding regions over 30 - 60 minutes. The oscillations are reduced by removing extracellular Ca2+ and blocking Cav 1.2/1.3 (L-type) Ca2+ channels. The oscillations are not affected by blocking AMPA receptors or by electrical stimulation of the parallel fiber - Purkinje cell circuit, suggesting the oscillations are generated intrinsically in the cerebellar cortex. Conversely, L-type Ca2+ agonists generate oscillations with similar properties. In the awake tg mouse, transcranial flavoprotein imaging revealed low frequency oscillations that are accentuated during caffeine induced attacks of dystonia. The oscillations increase during the attacks of dystonia and are coupled to oscillations in face and hindlimb EMG activity. These transient oscillations and the associated cerebellar dysfunction provide a novel mechanism by which an ion channel disorder results in episodic motor dysfunction.

  10. Slow desiccation leads to high-frequency shoot recovery from transformed somatic embryos of cotton (Gossypium hirsutum L. cv. Coker 310 FR).

    Science.gov (United States)

    Chaudhary, B; Kumar, S; Prasad, K V S K; Oinam, G S; Burma, P K; Pental, D

    2003-06-01

    In Agrobacterium-mediated genetic transformation of cotton (Gossypium hirsutum L. cv. Coker 310FR) the frequency at which somatic embryos were converted to plantlets was significantly improved by subjecting the embryos to slow physical desiccation. We used Agrobacterium strain GV3101 containing the binary vector pGSFR with the nos-nptII gene for in vitro selection and the 35S gus-int fragment as a reporter to optimize the transformation protocol. Although the concentration of kanamycin was reduced during embryogenesis and embryo maturation, even at the lower levels somatic embryos were predominantly abnormal, showing hypertrophy and reduced or fused cotyledons or poor radicle ends. A majority of these embryos (more than 75%) were beta-glucuronidase (GUS)-positive. Embryos with an abnormal appearance showed a very poor conversion to plantlets. However, these embryos, when subjected to slow physical desiccation followed by transfer to fresh medium, regenerated single or multiple shoots from the cotyledonary end. These shoots could be grafted on wild-type seedling stocks in vitro, which, following their transfer to soil, developed normally and set seeds. Regenerated plants tested positive for the transgene by Southern analysis. An overall scheme for the high-frequency production of cotton transgenics from both normal and abnormal appearing somatic embryos is presented.

  11. High-frequency transformation of a methylotrophic yeast, Candida boidinii, with autonomously replicating plasmids which are also functional in Saccharomyces cerevisiae.

    Science.gov (United States)

    Sakai, Y; Goh, T K; Tani, Y

    1993-06-01

    We have developed a transformation system which uses autonomous replicating plasmids for a methylotrophic yeast, Candida boidinii. Two autonomous replication sequences, CARS1 and CARS2, were newly cloned from the genome of C. boidinii. Plasmids having both a CARS fragment and the C. boidinii URA3 gene transformed C. boidinii ura3 cells to Ura+ phenotype at frequencies of up to 10(4) CFU/micrograms of DNA. From Southern blot analysis, CARS plasmids seemed to exist in polymeric forms as well as in monomeric forms in C. boidinii cells. The C. boidinii URA3 gene was overexpressed in C. boidinii on these CARS vectors. CARS1 and CARS2 were found to function as an autonomous replicating element in Saccharomyces cerevisiae as well. Different portions of the CARS1 sequence were needed for autonomous replicating activity in C. boidinii and S. cerevisiae. C. boidinii could also be transformed with vectors harboring a CARS fragment and the S. cerevisiae URA3 gene.

  12. Epileptic Seizure Detection based on Wavelet Transform Statistics Map and EMD Method for Hilbert-Huang Spectral Analyzing in Gamma Frequency Band of EEG Signals

    Directory of Open Access Journals (Sweden)

    Morteza Behnam

    2015-08-01

    Full Text Available Seizure detection using brain signal (EEG analysis is the important clinical methods in drug therapy and the decisions before brain surgery. In this paper, after signal conditioning using suitable filtering, the Gamma frequency band has been extracted and the other brain rhythms, ambient noises and the other bio-signal are canceled. Then, the wavelet transform of brain signal and the map of wavelet transform in multi levels are computed. By dividing the color map to different epochs, the histogram of each sub-image is obtained and the statistics of it based on statistical momentums and Negentropy values are calculated. Statistical feature vector using Principle Component Analysis (PCA is reduced to one dimension. By EMD algorithm and sifting procedure for analyzing the data by Intrinsic Mode Function (IMF and computing the residues of brain signal using spectrum of Hilbert transform and Hilbert – Huang spectrum forming, one spatial feature based on the Euclidian distance for signal classification is obtained. By K-Nearest Neighbor (KNN classifier and by considering the optimal neighbor parameter, EEG signals are classified in two classes, seizure and non-seizure signal, with the rate of accuracy 76.54% and with variance of error 0.3685 in the different tests.

  13. Linking High Frequency Variations in Stream Water DOC to Ages of Water Sources in Peat-Dominated Montane Watersheds

    Science.gov (United States)

    Tunaley, C.; Tetzlaff, D.; Lessels, J. S.; Soulsby, C.

    2015-12-01

    We combined time series of inferred DOC (from optical sensors) and stable isotopes in streams and watershed source areas to assess the link between water age and C fluxes. We monitored temporal dynamics of FDOM for 2 yrs at nested scales (0.9, 3.0 and 30km2) in a montane Scottish watershed. FDOM was strongly correlated (r2 ~ 0.8) with DOC allowing inference of 15 min timeseries. Marked seasonality was observed, with highest DOC concentrations (~25 mg l-1) in summer events and lower concentrations (~5mg l-1) in winter. During events, anticlockwise hysteresis was observed; consistent with expansion of the riparian saturation zone, increasing hydrological connectivity across peat soils and mobilizing DOC. Lag times for peak discharge and DOC were 1-12 hrs depending on event characteristics and antecedent conditions. Isotope time series from precipitation, streams and catchment source waters (overland flow and hillslope drainage) were also generated. These allowed us to model the non-stationary characteristics of their ages. Stream water age ranges from 3 months at high flows when overland flow dominates runoff to 4 yrs under baseflow. Overland flow age was a dominant influence on DOC transport. Highest concentrations occurred in small summer events with relatively young (strategies.

  14. Pupil Dilation and EEG Alpha Frequency Band Power Reveal Load on Executive Functions for Link-Selection Processes during Text Reading.

    Directory of Open Access Journals (Sweden)

    Christian Scharinger

    Full Text Available Executive working memory functions play a central role in reading comprehension. In the present research we were interested in additional load imposed on executive functions by link-selection processes during computer-based reading. For obtaining process measures, we used a methodology of concurrent electroencephalographic (EEG and eye-tracking data recording that allowed us to compare epochs of pure text reading with epochs of hyperlink-like selection processes in an online reading situation. Furthermore, this methodology allowed us to directly compare the two physiological load-measures EEG alpha frequency band power and pupil dilation. We observed increased load on executive functions during hyperlink-like selection processes on both measures in terms of decreased alpha frequency band power and increased pupil dilation. Surprisingly however, the two measures did not correlate. Two additional experiments were conducted that excluded potential perceptual, motor, or structural confounds. In sum, EEG alpha frequency band power and pupil dilation both turned out to be sensitive measures for increased load during hyperlink-like selection processes in online text reading.

  15. Calculations and measurements of the deuterium tunneling frequency in the propiolic acid-formic acid dimer and description of a newly constructed Fourier transform microwave spectrometer.

    Science.gov (United States)

    Sun, Ming; Wang, Yimin; Carey, Spencer J; Mitchell, Erik G; Bowman, Joel; Kukolich, Stephen G

    2013-08-28

    The concerted proton tunneling frequency for the propiolic acid-formic acid dimer was calculated using a relaxed ab initio double-well potential in the imaginary-frequency mode of the saddle point, and new measurements were made for the deuterated propiolic acid-formic acid (ProOD-FAOD) isotopologue. It is important to have consistent calculated tunneling frequency values between normal and deuterated isotopologues since parameters can be readily adjusted to get good agreement with one isotopologue. High-resolution rotational spectra of deuterated (ProOD-FAOD) dimer were measured using a newly constructed Fourier Transform microwave spectrometer. The new spectrometer has mirror size: 30 cm in diameter with a radius of curvature of 59 cm and is equipped with multiple-FID data collection (5-10 FID's for each gas pulse). For the deuterated (ProOD-FAOD) isotopologue, 45 rotational lines (a type: 34; b type: 11) were measured in the lowest tunneling states range between 6.5 GHz and 15.5 GHz. With the new high-resolution measurements of the tunneling doublets (b-dipole transitions), the double potential well responsible for the deuterium tunneling was depicted much more precisely. The two tunneling states are separated by 3.48 MHz. The rotational constants obtained in this work are quite helpful for further structure analysis as well.

  16. Frequency Band Analysis of Electrocardiogram (ECG) Signals for Human Emotional State Classification Using Discrete Wavelet Transform (DWT).

    Science.gov (United States)

    Murugappan, Murugappan; Murugappan, Subbulakshmi; Zheng, Bong Siao

    2013-07-01

    [Purpose] Intelligent emotion assessment systems have been highly successful in a variety of applications, such as e-learning, psychology, and psycho-physiology. This study aimed to assess five different human emotions (happiness, disgust, fear, sadness, and neutral) using heart rate variability (HRV) signals derived from an electrocardiogram (ECG). [Subjects] Twenty healthy university students (10 males and 10 females) with a mean age of 23 years participated in this experiment. [Methods] All five emotions were induced by audio-visual stimuli (video clips). ECG signals were acquired using 3 electrodes and were preprocessed using a Butterworth 3rd order filter to remove noise and baseline wander. The Pan-Tompkins algorithm was used to derive the HRV signals from ECG. Discrete wavelet transform (DWT) was used to extract statistical features from the HRV signals using four wavelet functions: Daubechies6 (db6), Daubechies7 (db7), Symmlet8 (sym8), and Coiflet5 (coif5). The k-nearest neighbor (KNN) and linear discriminant analysis (LDA) were used to map the statistical features into corresponding emotions. [Results] KNN provided the maximum average emotion classification rate compared to LDA for five emotions (sadness - 50.28%; happiness - 79.03%; fear - 77.78%; disgust - 88.69%; and neutral - 78.34%). [Conclusion] The results of this study indicate that HRV may be a reliable indicator of changes in the emotional state of subjects and provides an approach to the development of a real-time emotion assessment system with a higher reliability than other systems.

  17. Suppression of optical beat interference-noise in orthogonal frequency division multiple access-passive optical network link using self-homodyne balanced detection

    Science.gov (United States)

    Won, Yong-Yuk; Jung, Sang-Min; Han, Sang-Kook

    2014-08-01

    A new technique, which reduces optical beat interference (OBI) noise in orthogonal frequency division multiple access-passive optical network (OFDMA-PON) links, is proposed. A self-homodyne balanced detection, which uses a single laser for the optical line terminal (OLT) as well as for the optical network unit (ONU), reduces OBI noise and also improves the signal to noise ratio (SNR) of the discrete multi-tone (DMT) signal. The proposed scheme is verified by transmitting quadrature phase shift keying (QPSK)-modulated DMT signal over a 20-km single mode fiber. The optical signal to noise ratio (OSNR), that is required for BER of 10-5, is reduced by 2 dB in the balanced detection compared with a single channel due to the cancellation of OBI noise in conjunction with the local laser.

  18. Two-step sequential cross-linking of sugar beet pectin for transforming zein nanoparticle-based Pickering emulsions to emulgels.

    Science.gov (United States)

    Soltani, Sahar; Madadlou, Ashkan

    2016-01-20

    Nanosized (<100 nm) zein spheres were employed for fabrication of a series of fish O/W Pickering emulsions. Although surface tension measurement informed the high potency of zein particles for interfacial adsorption, the prepared emulsions destabilized shortly. Electrostatic deposition of sugar beet pectin onto zein particles interfacial layer at pH 4.0 increased significantly the emulsion stability which was attributed to enhanced steric and electrostatic repulsions based on ζ-potential measurements. Pectin enrichment also increased the viscosity of the continuous phase of emulsion. Injection of the oxidative enzyme laccase into the pectin-enriched emulsion to cross-link the feruloyl-bearing pectin molecules and the subsequent addition of CaCl2 to set ion-mediated cross-linkages between carboxyl groups of pectin chains transformed Pickering emulsions to emulgels. The higher the pectin content, the shorter was the gelation time of emulsions. The obtained emulgels were self-standing and became harder along with increasing pectin content.

  19. A stationary wavelet transform and a time-frequency based spike detection algorithm for extracellular recorded data

    Science.gov (United States)

    Lieb, Florian; Stark, Hans-Georg; Thielemann, Christiane

    2017-06-01

    Objective. Spike detection from extracellular recordings is a crucial preprocessing step when analyzing neuronal activity. The decision whether a specific part of the signal is a spike or not is important for any kind of other subsequent preprocessing steps, like spike sorting or burst detection in order to reduce the classification of erroneously identified spikes. Many spike detection algorithms have already been suggested, all working reasonably well whenever the signal-to-noise ratio is large enough. When the noise level is high, however, these algorithms have a poor performance. Approach. In this paper we present two new spike detection algorithms. The first is based on a stationary wavelet energy operator and the second is based on the time-frequency representation of spikes. Both algorithms are more reliable than all of the most commonly used methods. Main results. The performance of the algorithms is confirmed by using simulated data, resembling original data recorded from cortical neurons with multielectrode arrays. In order to demonstrate that the performance of the algorithms is not restricted to only one specific set of data, we also verify the performance using a simulated publicly available data set. We show that both proposed algorithms have the best performance under all tested methods, regardless of the signal-to-noise ratio in both data sets. Significance. This contribution will redound to the benefit of electrophysiological investigations of human cells. Especially the spatial and temporal analysis of neural network communications is improved by using the proposed spike detection algorithms.

  20. Design and implementation in VHDL code of the two-dimensional fast Fourier transform for frequency filtering, convolution and correlation operations

    Energy Technology Data Exchange (ETDEWEB)

    Vilardy, Juan M; Giacometto, F; Torres, C O; Mattos, L, E-mail: vilardy.juan@unicesar.edu.co [Laboratorio de Optica e Informatica, Universidad Popular del Cesar, Sede balneario Hurtado, Valledupar, Cesar (Colombia)

    2011-01-01

    The two-dimensional Fast Fourier Transform (FFT 2D) is an essential tool in the two-dimensional discrete signals analysis and processing, which allows developing a large number of applications. This article shows the description and synthesis in VHDL code of the FFT 2D with fixed point binary representation using the programming tool Simulink HDL Coder of Matlab; showing a quick and easy way to handle overflow, underflow and the creation registers, adders and multipliers of complex data in VHDL and as well as the generation of test bench for verification of the codes generated in the ModelSim tool. The main objective of development of the hardware architecture of the FFT 2D focuses on the subsequent completion of the following operations applied to images: frequency filtering, convolution and correlation. The description and synthesis of the hardware architecture uses the XC3S1200E family Spartan 3E FPGA from Xilinx Manufacturer.

  1. Application of Fast Fourier Transform in Frequency and Spectrum Analysis%快速傅里叶变换在频谱分析中的应用

    Institute of Scientific and Technical Information of China (English)

    胡丽莹; 肖蓬

    2011-01-01

    在快速傅里叶变换原理和Cooley-Tukey快速傅里叶变换算法的基础上,给出一个新的应用于数字信号处理(DSP)的频谱分析方法,并分析该方法的运算效率和存储空间开销.实例证明,本方法的复数乘法运算量与存储空间开销均较小,符合DSP信号处理器的特点,适合应用于采用高性能DSP的MP3/MP4或手机等消费电子产品.%Based on fast Fourier transform principle and Cooley-Tukey fast Fourier transform algorithm, a new method of frequency and spectrum analysis which applies in digital signal processing (DSP) is presented, and the operational efficiency and memory space of the method are analyzed. Example shows that the new method have less amount of complex multiplication and small memory space which is fit for DSP. So the method is very suitable for MP3/MP4 or mobile phone and other consumer electronic products which use high-performance DSP.

  2. Transformation of frequency-magnitude relation prior to large events in the model of block structure dynamics

    Directory of Open Access Journals (Sweden)

    A. Soloviev

    2008-02-01

    Full Text Available The b-value change in the frequency-magnitude (FM distribution for a synthetic earthquake catalogue obtained by means of the model of block structure dynamics has been studied. The catalogue is divided into time periods preceding strong earthquakes and time periods that do not precede strong earthquakes. The separate analysis of these periods shows that the b-value is smaller before strong earthquakes. The similar phenomenon has been found also for the observed seismicity of the Southern California. The model of block structure dynamics represents a seismic region as a system of perfectly rigid blocks divided by infinitely thin plane faults. The blocks interact between themselves and with the underlying medium. The system of blocks moves as a consequence of prescribed motion of the boundary blocks and of the underlying medium. As the blocks are perfectly rigid, all deformation takes place in the fault zones and at the block base in contact with the underlying medium. Relative block displacements take place along the fault zones. Block motion is defined so that the system is in a quasistatic equilibrium state. The interaction of blocks along the fault zones is viscous-elastic ("normal state" while the ratio of the stress to the pressure remains below a certain strength level. When the critical level is exceeded in some part of a fault zone, a stress-drop ("failure" occurs (in accordance with the dry friction model, possibly causing failure in other parts of the fault zones. These failures produce earthquakes. Immediately after the earthquake and for some time after, the affected parts of the fault zones are in a state of creep. This state differs from the normal state because of a faster growth of inelastic displacements, lasting until the stress falls below some other level. This numerical simulation gives rise a synthetic earthquake catalogue.

  3. Transformer Winding Frequency Response Data Analysis with Block Frequency Point Method%变压器绕组频率响应数据的图块频点分析法

    Institute of Scientific and Technical Information of China (English)

    许渊; 弓艳朋; 刘有为; 马文媛; 赵强; 王文焕

    2014-01-01

    Frequency response analysis is an important method of detecting transformer winding deformation.Experienced professionals are able to j udge winding deformation accurately by qualitative analysis of the frequency response data atlas. Firstly,the qualitative analysis methods for frequency response data are summarized.Secondly,according to the characteristics of the qualitative analysis,the mathematical morphology is introduced and the quantitative analysis for the amplitude difference is researched.The frequency domain is defined to divide the extreme points of the frequency response data into matched extreme point,shifted extreme point,lost extreme point,excess extreme point and the quantitative analysis for the extreme points is researched.Finally,the block frequency point method is proposed.The main points of the qualitative analysis for frequency response data atlas are mathematically presented with the block frequency point method,and the quantitative analysis for frequency response data is realized.The effectiveness of the method is proved by verification of an example.%频率响应分析法是诊断电力变压器绕组变形的重要方法。经验丰富的专业人员通过对频率响应数据图谱的定性分析,可以较准确地判断绕组变形。文中首先对频率响应数据的定性分析方法进行了总结;然后根据频率响应数据定性分析的特点,将数学形态学引入频率响应数据分析中,研究了频率响应数据幅值差异的量化分析方法,定义了频点域的概念,将频率响应数据的极值点分为匹配极值点、偏移极值点、缺失极值点和多出极值点,研究了频率响应数据极值点的量化分析方法;最后提出了频率响应数据的图块频点分析法,将频率响应数据图谱定性分析的要点用数学的方式表达出来,实现了对频率响应数据的量化分析。经过实例验证表明,该方法可以取得较好的诊断效果。

  4. The influence of transformation twins on seismic-frequency anelasticity in perovskite: an investigation using stroboscopic XRD-DMA

    Science.gov (United States)

    Harrison, R.; Redfern, S.; Buckley, A.; Salje, E.

    2003-04-01

    Recent experimental and theoretical studies suggest that the lower mantle is significantly anelastic. The origin of this anelasticity remains uncertain, however. One possible cause is the viscous motion of twin domain walls. Here we use a combination of dynamical mechanical analysis (DMA) and stroboscopic X-ray diffraction (XRD) to study the effect of domain walls on seismic-frequency anelasticity in perovskite at high temperature. We apply the technique to single crystal LaAlO_3, a close structural analogue of the MgSiO_3 perovskite phase believed to make up more than 70% of the Earth's lower mantle. We demonstrate that superelastic behaviour associated with the motion of domain walls dominates the mechanical response over a temperature range spanning several hundred degrees. This is accompanied by a factor-of-ten decrease in the effective Young's modulus below the cubic to rhombohedral phase transition and a rapid increase in attenuation. Freezing of domain walls at lower temperatures leads to mechanical stiffening and a broad peak in attenuation (tand >0.9 at 200^oC and 1 Hz). The observations indicate that domain walls are strongly pinned by oxygen vacancies. The combination of DMA and XRD permits the response of domain walls to a dynamic force to be observed in-situ for the very first time. The XRD-DMA machine consists of a standard Perkin-Elmer DMA-7e in three-point bend geometry, combined with a conventional X-ray source and position sensitive detector. The X-ray source is movable, allowing X-rays to be focused on the underside of the sample at a wide range of incident angles. Measuring diffracted intensity as a function of incident angle results in a conventional rocking curve, permitting the twin microstructure to be quantified. During a DMA measurement, X-rays are binned into four separate spectra, which are synchronised to four different stages of the dynamic force cycle. In this way, changes in microstructure which occur directly in response to the

  5. Transformers: analysis, design, and measurement

    National Research Council Canada - National Science Library

    López-Fernández, Xose M; Ertan, H. Bülent; Turowski, J

    2013-01-01

    "This book focuses on contemporary economic, design, diagnostics, and maintenance aspects of power, instrument, and high frequency transformers, which are critical to designers for a transformer stations...

  6. A fast method for the detection of vascular structure in images, based on the continuous wavelet transform with the Morlet wavelet having a low central frequency

    Science.gov (United States)

    Postnikov, Eugene B.; Tsoy, Maria O.; Kurochkin, Maxim A.; Postnov, Dmitry E.

    2017-04-01

    A manual measurement of blood vessels diameter is a conventional component of routine visual assessment of microcirculation, say, during optical capillaroscopy. However, many modern optical methods for blood flow measurements demand the reliable procedure for a fully automated detection of vessels and estimation of their diameter that is a challenging task. Specifically, if one measure the velocity of red blood cells by means of laser speckle imaging, then visual measurements become impossible, while the velocity-based estimation has their own limitations. One of promising approaches is based on fast switching of illumination type, but it drastically reduces the observation time, and hence, the achievable quality of images. In the present work we address this problem proposing an alternative method for the processing of noisy images of vascular structure, which extracts the mask denoting locations of vessels, based on the application of the continuous wavelet transform with the Morlet wavelet having small central frequencies. Such a method combines a reasonable accuracy with the possibility of fast direct implementation to images. Discussing the latter, we describe in details a new MATLAB program code realization for the CWT with the Morlet wavelet, which does not use loops completely replaced with element-by-element operations that drastically reduces the computation time.

  7. A novel three-phase UPS system with a single-phase resonant HF link

    OpenAIRE

    Darwish, MK

    2006-01-01

    This paper presents a new three-phase uninterruptible power supply (UPS) system based on a single-phase resonant high frequency (HF) link and a single-phase transformer. The three-phase output voltage is constructed and regulated from a three-phase cycloconverter fed from the constant amplitude, constant frequency link voltage. The generation of a novel switching stategy for the three-phase cycloconverter is presented. The simulation of the proposed system is carried out and verified with exp...

  8. Fourier and Laplace Transforms

    NARCIS (Netherlands)

    Beerends, R.J.; Morsche, ter H.G.; Berg, van den J.C.

    2003-01-01

    This textbook presents in a unified manner the fundamentals of both continuous and discrete versions of the Fourier and Laplace transforms. These transforms play an important role in the analysis of all kinds of physical phenomena. As a link between the various applications of these transforms the a

  9. Transforming Growth Factor-β1 T869C Gene Polymorphism Is Associated with Acquired Sick Sinus Syndrome via Linking a Higher Serum Protein Level

    OpenAIRE

    Chen, Jan-Yow; Liu, Jiung-Hsiun; Wu, Hong-Dar Isaac; Lin, Kuo-Hung; Chang, Kuan-Cheng; Liou, Ying-Ming

    2016-01-01

    Background Familial sick sinus syndrome is associated with gene mutations and dysfunction of ion channels. In contrast, degenerative fibrosis of the sinus node tissue plays an important role in the pathogenesis of acquired sick sinus syndrome. There is a close relationship between transforming growth factor-β1 mediated cardiac fibrosis and acquired arrhythmia. It is of interest to examine whether transforming growth factor-β1 is involved in the pathogenesis of acquired sick sinus syndrome. Me...

  10. [A method of object detection for remote sensing-imagery based on spectral space transformation].

    Science.gov (United States)

    Wu, Gui-Ping; Xiao, Peng-Feng; Feng, Xue-Zhi; Wang, Ke

    2013-03-01

    Object detection is an intermediate link for remote sensing image processing, which is an important guarantee of remote sensing application and services aspects. In view of the characteristics of remotely sensed imagery in frequency domain, a novel object detection algorithm based on spectral space transformation was proposed in the present paper. Firstly, the Fourier transformation method was applied to transform the image in spatial domain into frequency domain. Secondly, the wedge-shaped sample and overlay analysis methods for frequency energy were used to decompose signal into different frequency spectrum zones, and the center frequency values of object's features were acquired as detection marks in frequency domain. Finally, object information was detected with the matched Gabor filters which have direction and frequency selectivity. The results indicate that the proposed algorithm here performs better and it has good detection capability in specific direction as well.

  11. Metallurgical transformations analysed in qualifications processes of fuse links in electric energy distribution; Transformacoes metalurgicas analisadas em processos de qualificacao de elos fusiveis de distribuicao de energia eletrica

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, Vera Lucia Antunes da; Mocarzel, Paulo Roberto; Furtado, Heloisa Cunha [Centro de Pesquisas de Energia Eletrica, Rio de Janeiro, RJ (Brazil)

    1993-12-31

    Simulation essays of operation conditions, through thermic cycles as well as results of analyses made before and after the essays with the characterization of structural variation occurred on the fuse link are presented

  12. Transmission system for distribution of video over long-haul optical point-to-point links using a microwave photonic filter in the frequency range of 0.01-10 GHz

    Science.gov (United States)

    Zaldívar Huerta, Ignacio E.; Pérez Montaña, Diego F.; Nava, Pablo Hernández; Juárez, Alejandro García; Asomoza, Jorge Rodríguez; Leal Cruz, Ana L.

    2013-12-01

    We experimentally demonstrate the use of an electro-optical transmission system for distribution of video over long-haul optical point-to-point links using a microwave photonic filter in the frequency range of 0.01-10 GHz. The frequency response of the microwave photonic filter consists of four band-pass windows centered at frequencies that can be tailored to the function of the spectral free range of the optical source, the chromatic dispersion parameter of the optical fiber used, as well as the length of the optical link. In particular, filtering effect is obtained by the interaction of an externally modulated multimode laser diode emitting at 1.5 μm associated to the length of a dispersive optical fiber. Filtered microwave signals are used as electrical carriers to transmit TV-signal over long-haul optical links point-to-point. Transmission of TV-signal coded on the microwave band-pass windows located at 4.62, 6.86, 4.0 and 6.0 GHz are achieved over optical links of 25.25 km and 28.25 km, respectively. Practical applications for this approach lie in the field of the FTTH access network for distribution of services as video, voice, and data.

  13. Genome-wide DNA methylation reprogramming in response to inorganic arsenic links inhibition of CTCF binding, DNMT expression and cellular transformation

    Science.gov (United States)

    Rea, Matthew; Eckstein, Meredith; Eleazer, Rebekah; Smith, Caroline; Fondufe-Mittendorf, Yvonne N.

    2017-02-01

    Chronic low dose inorganic arsenic (iAs) exposure leads to changes in gene expression and epithelial-to-mesenchymal transformation. During this transformation, cells adopt a fibroblast-like phenotype accompanied by profound gene expression changes. While many mechanisms have been implicated in this transformation, studies that focus on the role of epigenetic alterations in this process are just emerging. DNA methylation controls gene expression in physiologic and pathologic states. Several studies show alterations in DNA methylation patterns in iAs-mediated pathogenesis, but these studies focused on single genes. We present a comprehensive genome-wide DNA methylation analysis using methyl-sequencing to measure changes between normal and iAs-transformed cells. Additionally, these differential methylation changes correlated positively with changes in gene expression and alternative splicing. Interestingly, most of these differentially methylated genes function in cell adhesion and communication pathways. To gain insight into how genomic DNA methylation patterns are regulated during iAs-mediated carcinogenesis, we show that iAs probably targets CTCF binding at the promoter of DNA methyltransferases, regulating their expression. These findings reveal how CTCF binding regulates DNA methyltransferase to reprogram the methylome in response to an environmental toxin.

  14. Genome-wide DNA methylation reprogramming in response to inorganic arsenic links inhibition of CTCF binding, DNMT expression and cellular transformation

    Science.gov (United States)

    Rea, Matthew; Eckstein, Meredith; Eleazer, Rebekah; Smith, Caroline; Fondufe-Mittendorf , Yvonne N.

    2017-01-01

    Chronic low dose inorganic arsenic (iAs) exposure leads to changes in gene expression and epithelial-to-mesenchymal transformation. During this transformation, cells adopt a fibroblast-like phenotype accompanied by profound gene expression changes. While many mechanisms have been implicated in this transformation, studies that focus on the role of epigenetic alterations in this process are just emerging. DNA methylation controls gene expression in physiologic and pathologic states. Several studies show alterations in DNA methylation patterns in iAs-mediated pathogenesis, but these studies focused on single genes. We present a comprehensive genome-wide DNA methylation analysis using methyl-sequencing to measure changes between normal and iAs-transformed cells. Additionally, these differential methylation changes correlated positively with changes in gene expression and alternative splicing. Interestingly, most of these differentially methylated genes function in cell adhesion and communication pathways. To gain insight into how genomic DNA methylation patterns are regulated during iAs-mediated carcinogenesis, we show that iAs probably targets CTCF binding at the promoter of DNA methyltransferases, regulating their expression. These findings reveal how CTCF binding regulates DNA methyltransferase to reprogram the methylome in response to an environmental toxin. PMID:28150704

  15. Determining insulation condition of 110kV instrument transformers. Linking PD measurement results from both gas chromatography and electrical method

    Science.gov (United States)

    Dan, C.; Morar, R.

    2017-05-01

    Working methods for on site testing of insulations: Gas chromatography (using the TFGA-P200 chromatographer); Electrical measurements of partial discharge levels using the digital detection, recording, analysis and partial discharge acquisition system, MPD600. First performed, between 2000-2015, were the chromatographic analyses concerning electrical insulating environments of: 102 current transformers, 110kV. Items in operation, functioning in 110/20kV substations. 38 voltage transformers, 110kV also in operation, functioning in 110/20kV substations. Then, electrical measurements of partial discharge inside instrument transformers, on site (power substations) were made (starting in the year 2009, over a 7-year period, collecting data until the year 2015) according to the provisions of standard EN 61869-1:2007 „Instrument transformers. General requirements”, applying, assimilated to it, type A partial discharge test procedure, using as test voltage the very rated 110kV distribution grid voltage. Given the results of two parallel measurements, containing: to this type of failure specific gas amount (H 2) and the quantitative partial discharge’ level, establishing a clear dependence between the quantity of partial discharges and the type and amount of in oil dissolved gases inside equipments affected by this type of defect: partial discharges, was expected. Of the „population” of instrument transformers subject of the two parallel measurements, the dependency between Q IEC (apparent charge) and (H 2) (hydrogen, gas amount dissolved within their insulating environment) represents a finite assemblage situated between the two limits developed on an empirical basis.

  16. Hardware Implementation of a Genetic Algorithm Based Canonical Singed Digit Multiplierless Fast Fourier Transform Processor for Multiband Orthogonal Frequency Division Multiplexing Ultra Wideband Applications

    Directory of Open Access Journals (Sweden)

    Mahmud Benhamid

    2009-01-01

    Full Text Available Problem statement: Ultra Wide Band (UWB technology has attracted many researchers' attention due to its advantages and its great potential for future applications. The physical layer standard of Multi-band Orthogonal Frequency Division Multiplexing (MB-OFDM UWB system is defined by ECMA International. In this standard, the data sampling rate from the analog-to-digital converter to the physical layer is up to 528 M sample sec-1. Therefore, it is a challenge to realize the physical layer especially the components with high computational complexity in Very Large Scale Integration (VLSI implementation. Fast Fourier Transform (FFT block which plays an important role in MB-OFDM system is one of these components. Furthermore, the execution time of this module is only 312.5 ns. Therefore, if employing the traditional approach, high power consumption and hardware cost of the processor will be needed to meet the strict specifications of the UWB system. The objective of this study was to design an Application Specific Integrated Circuit (ASIC FFT processor for this system. The specification was defined from the system analysis and literature research. Approach: Based on the algorithm and architecture analysis, a novel Genetic Algorithm (GA based Canonical Signed Digit (CSD Multiplier less 128-point FFT processor and its inverse (IFFT for MB-OFDM UWB systems had been proposed. The proposed pipelined architecture was based on the modified Radix-22 algorithm that had same number of multipliers as that of the conventional Radix-22. However, the multiplication complexity and the ROM memory needed for storing twiddle factors coefficients could be eliminated by replacing the conventional complex multipliers with a newly proposed GA optimized CSD constant multipliers. The design had been coded in Verilog HDL and targeted Xilinx Virtex-II FPGA series. It was fully implemented and tested on real hardware using Virtex-II FG456 prototype board and logic analyzer

  17. Degradation feature extraction of the hydraulic pump based on high-frequency harmonic local characteristic-scale decomposition sub-signal separation and discrete cosine transform high-order singular entropy

    Directory of Open Access Journals (Sweden)

    Jian Sun

    2016-07-01

    Full Text Available Hydraulic pump degradation feature extraction is a key step of condition-based maintenance. In this article, a novel method based on high-frequency harmonic local characteristic-scale decomposition sub-signal separation and discrete cosine transform high-order singular entropy is proposed. In order to reduce noises and other disturbances, the vibration signal is processed by the local characteristic-scale decomposition modified by the high-frequency harmonic. Sub-signal with sensitive information is obtained by blind source separation of the selected intrinsic scale components. Furthermore, the discrete cosine transform high-order spectral analysis algorithm is proposed to extract singular entropies of Shannon and Tsallis to be the degradation features of the hydraulic pump. Analysis of the hydraulic pump experiment demonstrates that the proposed method is feasible and effective in indicating the performance degradation of the hydraulic pump.

  18. Global gene expression profiling of brown to white adipose tissue transformation in sheep reveals novel transcriptional components linked to adipose remodeling

    DEFF Research Database (Denmark)

    Basse, Astrid L.; Dixen, Karen; Yadav, Rachita;

    2015-01-01

    NR1H3, MYC, KLF4, ESR1, RELA and BCL6, which were linked to the overall changes in gene expression during the adipose tissue remodeling. Finally, the perirenal adipose tissue expressed both brown and brite/beige adipocyte marker genes at birth, the expression of which changed substantially over time...

  19. Global gene expression profiling of brown to white adipose tissue transformation in sheep reveals novel transcriptional components linked to adipose remodeling

    DEFF Research Database (Denmark)

    Basse, Astrid L.; Dixen, Karen; Yadav, Rachita;

    2015-01-01

    abundance and down-regulation of gene expression related to mitochondrial function and oxidative phosphorylation. Global gene expression profiling demonstrated that the time points grouped into three phases: a brown adipose phase, a transition phase and a white adipose phase. Between the brown adipose......Background: Large mammals are capable of thermoregulation shortly after birth due to the presence of brown adipose tissue (BAT). The majority of BAT disappears after birth and is replaced by white adipose tissue (WAT). Results: We analyzed the postnatal transformation of adipose in sheep...... with a time course study of the perirenal adipose depot. We observed changes in tissue morphology, gene expression and metabolism within the first two weeks of postnatal life consistent with the expected transition from BAT to WAT. The transformation was characterized by massively decreased mitochondrial...

  20. Unusual Transformation from a Solvent-Stabilized 1D Coordination Polymer to a Metal-Organic Framework (MOF)-Like Cross-Linked 3D Coordination Polymer.

    Science.gov (United States)

    Lee, Seung-Chul; Choi, Eun-Young; Lee, Sang-Beom; Kim, Sang-Wook; Kwon, O-Pil

    2015-10-26

    An unusual 1D-to-3D transformation of a coordination polymer based on organic linkers containing highly polar push-pull π-conjugated side chains is reported. The coordination polymers are synthesized from zinc nitrate and an organic linker, namely, 2,5-bis{4-[1-(4-nitrophenyl)pyrrolidin-2-yl]butoxy}terephthalic acid, which possesses highly polar (4-nitrophenyl)pyrrolidine groups, with high dipole moments of about 7 D. The coordination polymers exhibit an unusual transformation from a soluble, solvent-stabilized 1D coordination polymer into an insoluble, metal-organic framework (MOF)-like 3D coordination polymer. The coordination polymer exhibits good film-forming ability, and the MOF-like films are insoluble in conventional organic solvents.

  1. Developing a survey instrument to assess the readiness of primary care data, genetic and disease registries to conduct linked research: TRANSFoRm International Research Readiness (TIRRE survey instrument

    Directory of Open Access Journals (Sweden)

    Emily Leppenwell

    2013-05-01

    Full Text Available Background Clinical data are collected for routine care in family practice; there are also a growing number of genetic and cancer registry data repositories. The Translational Research and Patient Safety in Europe (TRANSFoRm project seeks to facilitate research using linked data from more than one source. We performed a requirements analysis which identified a wide range of data and business process requirements that need to be met before linking primary care and either genetic or disease registry data.Objectives To develop a survey to assess the readiness of data repositories to participate in linked research – the Transform International Research Readiness (TIRRE survey.Method We develop the questionnaire based on our requirement analysis; with questions at micro-, meso- and macro levels of granularity, study-specific questions about diabetes and gastro-oesophageal reflux disease (GORD, and research track record. The scope of the data required was extensive. We piloted this instrument, conducting ten preliminary telephone interviews to evaluate the response to the questionnaire.Results Using feedback gained from these interviews we revised the questionnaire; clarifying questions that were difficult to answer and utilising skip logic to create different series of questions for the various types of data repository. We simplified the questionnaire replacing free-text responses with yes/no or picking list options, wherever possible. We placed the final questionnaire online and encouraged its use (www.clininf.eu/jointirre/info.html.Conclusion Limited field testing suggests that TIRRE is capable of collecting comprehensive and relevant data about the suitability and readiness of data repositories to participate in linked data research.

  2. Unmanned Aerial System and Spaceflight Microwave Radiometers? Radio-Frequency Interference Direct Detection and Science Data Recovery Based on the Hilbert-Huang Transform for Two Dimensions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The three goals of this IRAD are:1.1 Research and develop the Hilbert-Huang Transform for 2D second and last component – the Hilbert Spectral Analysis for 2D...

  3. Transformers analysis, design, and measurement

    CERN Document Server

    Lopez-Fernandez, Xose M; Turowski, Janusz

    2012-01-01

    This book focuses on contemporary economic, design, diagnostics, and maintenance aspects of power, instrument, and high frequency transformers, which are critical to designers for a transformer stations. The text covers such topics as shell type and superconducting transformers as well as coreless PCB and planar transformers. It emphasizes challenges and strategies in transformer design and illustrates the importance of economics in transformers management by reviewing life cycle cost design and the use of decision methods to manage risk.

  4. Consumption Frequency of Foods Away from Home Linked with Higher Body Mass Index and Lower Fruit and Vegetable Intake among Adults: A Cross-Sectional Study

    Directory of Open Access Journals (Sweden)

    Rebecca A. Seguin

    2016-01-01

    Full Text Available Introduction. Consumption of foods prepared away from home (FAFH has grown steadily since the 1970s. We examined the relationship between FAFH and body mass index (BMI and fruit and vegetable (FV consumption. Methods. Frequency of FAFH, daily FV intake, height and weight, and sociodemographic data were collected using a telephone survey in 2008-2009. Participants included a representative sample of 2,001 adult men and women (mean age 54±15 years residing in King County, WA, with an analytical sample of 1,570. Frequency of FAFH was categorized as 0-1, 2–4, or 5+ times per week. BMI was calculated from self-reported height and weight. We examined the relationship between FAFH with FV consumption and BMI using multivariate models. Results. Higher frequency of FAFH was associated with higher BMI, after adjusting for age, income, education, race, smoking, marital status, and physical activity (women: p=0.001; men: p=0.003. There was a negative association between frequency of FAFH and FV consumption. FAFH frequency was significantly (p<0.001 higher among males than females (43.1% versus 54.0% eating out 0-1 meal per week, resp.. Females reported eating significantly (p<0.001 more FV than males. Conclusion. Among adults, higher frequency of FAFH was related to higher BMI and less FV consumption.

  5. The small GTP-binding protein Rho links G protein-coupled receptors and Gα12 to the serum response element and to cellular transformation

    Science.gov (United States)

    Fromm, Christian; Coso, Omar A.; Montaner, Silvia; Xu, Ningzhi; Gutkind, J. Silvio

    1997-01-01

    Receptors coupled to heterotrimeric G proteins can effectively stimulate growth promoting pathways in a large variety of cell types, and if persistently activated, these receptors can also behave as dominant-acting oncoproteins. Consistently, activating mutations for G proteins of the Gαs and Gαi2 families were found in human tumors; and members of the Gαq and Gα12 families are fully transforming when expressed in murine fibroblasts. In an effort aimed to elucidate the molecular events involved in proliferative signaling through heterotrimeric G proteins we have focused recently on gene expression regulation. Using NIH 3T3 fibroblasts expressing m1 muscarinic acetylcholine receptors as a model system, we have observed that activation of this transforming G protein-coupled receptors induces the rapid expression of a variety of early responsive genes, including the c-fos protooncogene. One of the c-fos promoter elements, the serum response element (SRE), plays a central regulatory role, and activation of SRE-dependent transcription has been found to be regulated by several proteins, including the serum response factor and the ternary complex factor. With the aid of reporter plasmids for gene expression, we observed here that stimulation of m1 muscarinic acetylcholine receptors potently induced SRE-driven reporter gene activity in NIH 3T3 cells. In these cells, only the Gα12 family of heterotrimeric G protein α subunits strongly induced the SRE, while Gβ1γ2 dimers activated SRE to a more limited extent. Furthermore, our study provides strong evidence that m1, Gα12 and the small GTP-binding protein RhoA are components of a novel signal transduction pathway that leads to the ternary complex factor-independent transcriptional activation of the SRE and to cellular transformation. PMID:9294169

  6. Dynamics of a combined Medea-underdominant population transformation system.

    Science.gov (United States)

    Gokhale, Chaitanya S; Reeves, Richard Guy; Reed, Floyd A

    2014-05-07

    Transgenic constructs intended to be stably established at high frequencies in wild populations have been demonstrated to "drive" from low frequencies in experimental insect populations. Linking such population transformation constructs to genes which render them unable to transmit pathogens could eventually be used to stop the spread of vector-borne diseases like malaria and dengue. Generally, population transformation constructs with only a single transgenic drive mechanism have been envisioned. Using a theoretical modelling approach we describe the predicted properties of a construct combining autosomal Medea and underdominant population transformation systems. We show that when combined they can exhibit synergistic properties which in broad circumstances surpass those of the single systems. With combined systems, intentional population transformation and its reversal can be achieved readily. Combined constructs also enhance the capacity to geographically restrict transgenic constructs to targeted populations. It is anticipated that these properties are likely to be of particular value in attracting regulatory approval and public acceptance of this novel technology.

  7. Cell transformation mediated by chromosomal deoxyribonucleic acid of polyoma virus-transformed cells

    Energy Technology Data Exchange (ETDEWEB)

    Della Valle, G.; Fenton, R.G.; Basilico, C.

    1981-05-01

    To study the mechanism of deoxyribonucleic acid (DNA)-mediated gene transfer, normal rat cells were transfected with total cellular DNA extracted from polyoma virus-transformed cells. This resulted in the appearance of the transformed phenotype in 1 x 10/sup -6/ to 3 x 10/sup -6/ of the transfected cells. Transformation was invariably associated with the acquisition of integrated viral DNA sequences characteristic of the donor DNA. This was caused not by the integration of free DNA molecules, but by the transfer of large DNA fragments (10 to 20 kilobases) containing linked cellular and viral sequences. Although Southern blot analysis showed that integration did not appear to occur in a homologus region of the recipient chromosome, the frequency of transformation was rather high when compared with that of purified polyoma DNA, perhaps due to ''position'' effects or to the high efficiency of recombination of large DNA fragments.

  8. Application of natural electric field frequency-selection method in the transformer substation groundwater survey%天然电场选频法在某变电站地下水勘察中的应用

    Institute of Scientific and Technical Information of China (English)

    王志斌; 南坤

    2015-01-01

    On the basis of analyzing surveying principles of natural electric field frequency-selection method,combining with engineering exam-ples,the article illustrates the application technology of natural electric field frequency-selection method in the transformer substation groundwater survey,and points out that:comparing to common geophysical methods for water exploration,natural electric field frequency-selection method is more simple and higher efficient.%在分析天然电场选频法勘察原理的基础上,结合工程实例,说明了天然电场选频法在变电站地下水勘察中的应用技术,指出与常规物探找水方法相比,天然电场选频法更加简单高效。

  9. Implementación de un Modelo de un Transformador Eléctrico para el Análisis de su Respuesta en Frecuencia Implementation of an Electric Transformer Model for its Frequency Response Analysis

    Directory of Open Access Journals (Sweden)

    Guillermo Aponte

    2011-01-01

    Full Text Available Este artículo presenta la implementación de un modelo para el análisis del comportamiento en frecuencia de los parámetros de un transformador eléctrico. El modelo se obtiene a partir de la curva de la prueba de Respuesta en Frecuencia del transformador (FRA. Esta prueba consiste básicamente en obtener una característica del transformador y comparar el resultado con una referencia del mismo, tomada anteriormente y considerada como normal. Las diferencias pueden indicar algún tipo de daño en el transformador. Se hace la descripción del modelo, de la manera como se realizó su implementación, del procedimiento para obtener sus parámetros y de su aplicación en el análisis de variaciones en las curvas obtenidas en los ensayos de FRA. Este modelo es una herramienta que puede emplearse como ayuda para identificar problemas de tipo mecánico en el transformador.This article presents the implementation of a model for the analysis of the frequency behavior of a transformer. The model is obtained from the Frequency Response Test (FRA. This test consists basically of obtaining the characteristics of the transformer and comparing the results with those of a reference transformer, which are previously known and considered as normal- The differences indicate that the transformer has certain damage. The article describes the model, its implementation, the procedure to obtain its parameters and its application in the analysis of the curve variations obtained by the FRA tests. This model represents a good tool that can be used as support to identify some type of mechanical problem in the transformer.

  10. Comparison of the frequency estimation of the DORIS/Jason2 oscillator thanks to the onboard DIODE and Time Transfer by Laser Link experiment

    Science.gov (United States)

    Jayles, C.; Exertier, P.; Martin, N.; Chauveau, J. P.; Samain, E.; Tourain, C.; Auriol, A.; Guillemot, P.

    2016-12-01

    The main applications for DORIS are precise orbit determination, and precise Geodesy. Onboard Jason-2 for instance, the DORIS tracking component is the French contribution to the precise orbit determination capability, a key capability for altimetry product scientific result accuracy. T2L2 is a time transfer technique based on the propagation of light pulses for synchronization between two clocks. Hosting T2L2 on-board Jason-2 was to allow for very fine DORIS USO (Ultra-Stable Oscillator) frequency monitoring, and for this purpose T2L2 was connected to the DORIS USO. Thanks to the continuous tracking of T2L2/Jason-2 by the Laser Ranging network it is possible to monitor the USO for several days, weeks, and even much longer, and thus to also compare with the DIODE (the DORIS on-board orbit determination software) frequency bias estimates. The DORIS USO frequency biases estimate comparison between two independent systems, T2L2 and DIODE, can be of benefit to both, allowing the accuracies of both systems to be better understood, and for improvements to be made to both systems. Such comparison is the central topic of the present paper. T2L2 monitors the DORIS on-board USO frequency with an accuracy of much better than 10-12 which is the specification for the Doppler instrumentation. The paper investigates the limits of the DORIS-DIODE frequency bias estimates using T2L2, showing that USO frequency compliance accuracy of 10-12 has been reached.

  11. Induced change of formative processes in pepper (Capsicum annuum L. ). I. Effect of mutagenic treatment on the crossingover frequency of the linked and recombination of unlinked marker genes

    Energy Technology Data Exchange (ETDEWEB)

    Samovol, A.P.

    1986-05-01

    The effect of mutagenic treatment of the F/sub 1/ seeds of pepper on the crossingover frequency in the al/sub 2/-b segment, monohybrid and dihybrid segregation for the unlinked marker genes al/sub 2/ and pi was studied. It has been demonstrated that treatment leads to a significant reduction in the crossover frequency in the al/sub 2/-b zone. Highly significant differences between the control and individual treatment of the hybrid seeds indicated reduction in recombinations due to the mutagens used. A case of induced deviation in independent segregation of al/sub 2/ and pi, i.e., quasilinkage has been recorded.

  12. Model Transformations? Transformation Models!

    NARCIS (Netherlands)

    Bézivin, J.; Büttner, F.; Gogolla, M.; Jouault, F.; Kurtev, I.; Lindow, A.

    2006-01-01

    Much of the current work on model transformations seems essentially operational and executable in nature. Executable descriptions are necessary from the point of view of implementation. But from a conceptual point of view, transformations can also be viewed as descriptive models by stating only the

  13. 输变电设施与家用电器对居室工频磁场的影响%Effect of Power Transmission and Transformation Facilities and Domestic Appliances on Indoor Power Frequency Magnetic Field

    Institute of Scientific and Technical Information of China (English)

    孙海燕

    2011-01-01

    目的 了解居民居室内磁场强度大于0.4 μT的情况.方法 采用德国Narda公司生产的EFA-300低频电磁场分析仪对输变电设施和居民家用电器的工频磁场强度进行监测.结果 距户外110 kV输变电设施15 m以上、距220 kV输变电设施65 m以上居室内工频磁场强度低于0.4 μT,而地埋式110 kV输变电设施在地面处的磁场强度基本都小于0.4 μT,故对居室内的磁场强度基本无影响;根据对家用电器周边工频磁场强度的监测结果,由于其功率、种类等的不同,相同距离处磁场强度数值不同,但离开其1 m位置处的磁场强度基本都小于0.4 μT.结论 叠加家用电器和输变电设施的工频磁场强度,在开启家用电器的工况下,居室内的工频磁场强度要高于关闭家用电器的工况.因此,为了避免室内磁场强度超过0.4 μT,应及时关闭家用电器,或远离开启中的家用电器,以减少磁场强度对人体的影响.%[ Objective ] To investigate the indoor power frequency magnetic fields intension that may exceed 0.4 μT. [ Methods ] The power frequency magnetic fields intension of power transmission and transformation facilities and domestic appliances was monitored with EFA-300 produced by Narda company in Germany. [ Results] According to the monitoring results, away from the outdoor 110kV power transmission and transformer facilities above 15m and away from the 220kV power transmission and transformer facilities above 65m, the indoor power frequency magnetic fields intension were all below 0.4 μT, while the underground 110 kV power transmission and transformer facilities caused no influence on indoor power frequency magnetic fields intension which were all below 0.4 μT at surface monitor spots. According to the monitoring results of the power frequency magnetic fields intension of domestic appliances,for the different power and type of the domestic appliances, the power frequency magnetic fields intension were

  14. Matched Wigner Transform and Its Application to Instantaneous Frequency Estimation%匹配 Wigner 变换及其在瞬时频率估计中的应用

    Institute of Scientific and Technical Information of China (English)

    徐灵基; 杨益新; 杨龙

    2014-01-01

    A novel time-frequency analysis method referred to as matched Wigner transform (MWT) was defined in this pa-per .By matching bilinear signal kernel with Taylor extended Fourier revolving factor ,MWT can produce a time-frequency distribu-tion (TFD ) with best concentration and without inner artifacts for mono-component high-order polynomial phase signal (PPS ) .In addition ,an effective parameter and instantaneous frequency (IF ) estimation algorithm was proposed based on MWT .The algorithm was validated by simulation examples .Finally ,excellent sea experiment results were obtained when applying it to analyze the weak Doppler signal of underwater moving acoustic source .%提出了一种新的时频分析方法,称为匹配Wigner变换(Matched Wigner Transform ,MWT )。该变换通过泰勒级数扩展傅立叶旋转因子e-jωτ来匹配双线性信号核,能够对单分量高阶多项式相位信号(Polynomial Phase Signal , PPS )分析得到聚集性最优的时频分布(Time Frequency Distribution ,TFD ),且克服了自交叉项的干扰。基于MWT ,给出了一种有效实现PPS的瞬时频率(Instantaneous Frequency ,IF)和参量估计的迭代算法,并通过仿真算例验证了算法的有效性。最后,将该方法应用于水下运动声源的微弱多普勒信号分析,得到良好的海试试验结果。

  15. 非降采样Contourlet域内空间频率激励的PCNN图像融合算法%Image Fusion Algorithm Based on Spatial Frequency-Motivated Pulse Coupled Neural Networks in Nonsubsampled Contourlet Transform Domain

    Institute of Scientific and Technical Information of China (English)

    屈小波; 闫敬文; 肖弘智; 朱自谦

    2008-01-01

    Nonsubsampled contourlet transform (NSCT) provides flexible multiresolution, anisotropy, and directional expansion for images. Compared with the original contourlet transform, it is shift-invariant and can overcome the pseudo-Gibbs phenomena around singularities. Pulse coupled neural networks (PCNN) is a visual cortex-inspired neural network and characterized by the global coupling and pulse synchronization of neurons. It has been proven suitable for image processing and successfully employed in image fusion. In this paper, NSCT is associated with PCNN and used in image fusion to make full use of the characteristics of them. Spatial frequency in NSCT domain is input to motivate PCNN and coefficients in NSCT domain with large firing times are selected as coefficients of the fused image. Experimental results demonstrate that the proposed algorithm outperforms typical wavelet-based, contourlet-based, PCNN-based, and contourlet-PCNN-based fusion algorithms in terms of objective criteria and visual appearance.

  16. Frequency Dependence of The Properties about High Permeability Ferrite and Transformer%高磁导率铁氧体及其变压器性质的频率依赖关系

    Institute of Scientific and Technical Information of China (English)

    王波; 裴谐第; 廖绍彬

    1999-01-01

    研究了高起始磁导率(6000~20 000)铁氧体和由该磁芯制成的变压器的电感频率依赖关系.当驱动频率由100Hz增加到300kHz时,电感呈现V形L-f曲线.详细讨论了形成V形曲线的原因.%The research of the high initial permeability(6000~20000)ferrite and the frequency dependence of inductance of the ferrite transformer made by high permeability ferrite core are presented. When the driving frequency increases from 100Hz to 300kHz the inductance shows a Vshape L-f curve. The reasons forming such a V-shape curve are discussed in detail.

  17. Study on Sound-absorbing Performance of Outdoor Composite Low Frequency Sound-absorbing Structure at Transformer Substation%变电站户外复合低频吸声结构的吸声性能研究

    Institute of Scientific and Technical Information of China (English)

    何钢; 郭宇春

    2013-01-01

    为治理变电站的低频噪声,根据共振吸声原理提出由薄板共振吸声结构和微穿孔板吸声结构构成的复合低频吸声结构,并利用土建阻抗管对复合吸声结构的垂直入射吸声系数进行测试并验证它的低频噪声吸声性能较好,即垂直入射吸声系数在100 Hz和200 Hz频率能达到0.8左右。对复合低频吸声体的研究对治理变电站的低频噪声具有实际意义。%In order to control low-frequency noise in the transformer substation, according to resonance sound absorption principle, this paper adopts low frequency sound absorption structure composed by sheet resonance sound-absorbing structure and micro-perforated plate sound absorbing structure. Besides, this paper does some tests of the vertical incidence to compound sound absorption structure by using civil impedance tube. During the test, low frequency sound-absorbing performance could be certificad and vertical incidence sound absorption coefficient could be up to 0.8 at 100 Hz and 200 Hz. This study has the practical significance on the treatment of low frequency noise in the transformer substation.

  18. LFM信号调频斜率的双正交Fourier变换分析算法%Analysis Algorithm to Frequency Rate of LFM Signal Based on Biorthogonal Fourier Transform

    Institute of Scientific and Technical Information of China (English)

    王本庆; 李兴国

    2009-01-01

    现有很多LFM信号调频斜率的分析算法,但这些算法存在诸多不足,如计算复杂、搜索时间长,对多LFM信号有交叉项等.该文提出了基于双正交Fourier变换的新LFM信号调频斜率分析算法,其特点是信号在双正交基下展开,通过变换得到信号调频斜率密度谱.该算法不需要搜索,且特别适合对不同调频斜率组成的多LFM信号进行调频斜率分析.文中推导了连续双正交Fourier变换公式和离散变换公式,并讨论了算法的一些主要性质.%There are many analysis algorithms for frequency rate of LFM signal, but those algorithms have some drawbacks, such as highly computational complexity, long time for searching, and cross-term in multi-LFM signal. In this paper, a new analysis algorithm of frequency rate of LFM signal is presented based on Biorthogonal Fourier Transform (BFT), the signal is expanded with biorthogonal base function that could be got frequency rate density spectrum of the signal. This algorithm need no searching, and has better performance for detection different frequency rate of multi-LFM signal. This paper derives continual BFT formula and discrete transform formula and discusses its some main characters.

  19. {sup 210}Pb and {sup 137}Cs as chronometers for salt marsh accretion in the Venice Lagoon - links to flooding frequency and climate change

    Energy Technology Data Exchange (ETDEWEB)

    Bellucci, L.G. [Istituto di Scienze Marine - Sede di Bologna - Geologia Marina, Consiglio Nazionale delle Ricerche, Via P. Gobetti 101, 40129 Bologna (Italy)], E-mail: luca.bellucci@ismar.cnr.it; Frignani, M. [Istituto di Scienze Marine - Sede di Bologna - Geologia Marina, Consiglio Nazionale delle Ricerche, Via P. Gobetti 101, 40129 Bologna (Italy); Cochran, J.K. [Marine Sciences Research Center, Stony Brook University, Stony Brook, New York 11794-5000, NY (United States); Albertazzi, S. [Istituto di Scienze Marine - Sede di Bologna - Geologia Marina, Consiglio Nazionale delle Ricerche, Via P. Gobetti 101, 40129 Bologna (Italy); Zaggia, L. [Istituto di Scienze Marine, Consiglio Nazionale delle Ricerche - S. Polo 1364, 30125 Venezia (Italy); Cecconi, G. [Consorzio Venezia Nuova - S. Croce 505, 30135 Venezia (Italy); Hopkins, H. [Marine Sciences Research Center, Stony Brook University, Stony Brook, New York 11794-5000, NY (United States)

    2007-10-15

    Five salt marsh sediment cores from different parts of the Venice Lagoon were studied to determine their depositional history and its relationship with the environmental changes occurred during the past {approx}100 years. X-radiographs of the cores show no disturbance related to particle mixing. Accretion rates were calculated using a constant flux model applied to excess {sup 210}Pb distributions in the cores. The record of {sup 137}Cs fluxes to the sites, determined from {sup 137}Cs profiles and the {sup 210}Pb chronologies, shows inputs from the global fallout of {sup 137}Cs in the late 1950s to early 1960s and the Chernobyl accident in 1986. Average accretion rates in the cores are comparable to the long-term average rate of mean sea level rise in the Venice Lagoon ({approx}0.25 cm y{sup -1}) except for a core collected in a marsh presumably affected by inputs from the Dese River. Short-term variations in accretion rate are correlated with the cumulative frequency of flooding, as determined by records of Acqua Alta, in four of the five cores, suggesting that variations in the phenomena causing flooding (such as wind patterns, storm frequency and NAO) are short-term driving forces for variations in marsh accretion rate.

  20. A Combined Antenna Arrays and Reverse-Link Synchronous DS-CDMA System over Frequency-Selective Fading Channels with Power Control Error

    Directory of Open Access Journals (Sweden)

    Yong-Seok Kim

    2004-08-01

    Full Text Available An improved antenna array (AA has been introduced, in which reverse-link synchronous transmission technique (RLSTT is incorporated to effectively make better an estimation of covariance matrices at a beamformer-RAKE receiver. While RLSTT is effective in the first finger at the RAKE receiver in order to reject multiple-access interference (MAI, the beamformer estimates the desired user's complex weights, enhancing its signal and reducing cochannel interference (CCI from the other directions. In this work, it is attempted to provide a comprehensive analysis of user capacity which reflects several important factors such as the shape of multipath intensity profile (MIP, the number of antennas, and power control error (PCE. Theoretical analysis, confirmed by the simulations, demonstrates that the orthogonality provided by employing RLSTT along with AA may make the DS-CDMA system insensitive to the PCE even with fewer numbers of antennas.

  1. REUSE-PARTITIONING-BASED FREQUENCY PLANNING FOR TWO-HOP CELLULAR NETWORKS WITH NLOS BS-RELAY LINKS%基于复用分割技术的中继蜂窝网的频率规划

    Institute of Scientific and Technical Information of China (English)

    李平; 戎蒙恬; 薛义生; 喻丹; 刘涛

    2007-01-01

    研究了两跳固定中继蜂窝网的频率规划问题.与其他固定中继蜂窝网的研究不同,假设了固定中继节点与其所属基站链路上没有任何性能增强技术,并在此假设条件下,根据复用分割原则,提出了两种新的中继频率规划方案.同时将提出的频率规划方案与基于信道借用的频率规划方案及传统无中继的频率规划方案进行了比较.理论分析和仿真结果表明, 所提出的频率规划方案不但能提高小区边缘用户的服务质量,且与基于信道借用的频率规划方案相比,能够获得更大的系统性能提高.研究结果还表明,为了充分发挥固定中继网络的潜力,有必要在固定中继节点与其所属基站链路上引入性能增强技术.%The frequency planning for a cellular system enhanced with two-hop fixed relay nodes (FRNs) is investigated. It is assumed that there is no performance-enhancing technique on the base station (BS)-FRN links. Under the assumed condition, two frequency planning schemes are proposed by the principle of reuse partitioning (RP). The frequency planning schemes are compared with the channel-borrowing-based frequency planning scheme and the conventional frequency planning scheme without relaying. Theoretical analysis and simulation results show that the proposed schemes can improve the service quality for mobile terminals close to cell boundaries and provide better performance over the channel-borrowing-based frequency planning. Finally, to fully exploit the potentials of FRN enhanced cellular system, some performance enhancing techniques on BS-FRN links are indispensable.

  2. Observations of wave transformation over a fringing coral reef and the importance of low-frequency waves and offshore water levels to runup, overwash, and coastal flooding

    Science.gov (United States)

    Cheriton, Olivia M.; Storlazzi, Curt D.; Rosenberger, Kurt J.

    2016-05-01

    Many low-lying tropical islands are susceptible to sea level rise and often subjected to overwash and flooding during large wave events. To quantify wave dynamics and wave-driven water levels on fringing coral reefs, a 5 month deployment of wave gauges and a current meter was conducted across two shore-normal transects on Roi-Namur Island in the Republic of the Marshall Islands. These observations captured two large wave events that had waves with maximum heights greater than 6 m with peak periods of 16 s over the fore reef. The larger event coincided with a peak spring tide, leading to energetic, highly skewed infragravity (0.04-0.004 Hz) and very low frequency (0.004-0.001 Hz) waves at the shoreline, which reached heights of 1.0 and 0.7 m, respectively. Water surface elevations, combined with wave runup, reached 3.7 m above the reef bed at the innermost reef flat adjacent to the toe of the beach, resulting in flooding of inland areas. This overwash occurred during a 3 h time window that coincided with high tide and maximum low-frequency reef flat wave heights. The relatively low-relief characteristics of this narrow reef flat may further drive shoreline amplification of low-frequency waves due to resonance modes. These results (1) demonstrate how the coupling of high offshore water levels with low-frequency reef flat wave energetics can lead to large impacts along fringing reef-lined shorelines, such as island overwash, and (2) lend support to the hypothesis that predicted higher sea levels will lead to more frequent occurrences of these extreme events, negatively impacting coastal resources and infrastructure.

  3. Observations of wave transformation over a fringing coral reef and the importance of low-frequency waves and offshore water levels to runup, overwash, and coastal flooding

    Science.gov (United States)

    Cheriton, Olivia; Storlazzi, Curt; Rosenberger, Kurt

    2016-01-01

    Many low-lying tropical islands are susceptible to sea level rise and often subjected to overwash and flooding during large wave events. To quantify wave dynamics and wave-driven water levels on fringing coral reefs, a 5 month deployment of wave gauges and a current meter was conducted across two shore-normal transects on Roi-Namur Island in the Republic of the Marshall Islands. These observations captured two large wave events that had waves with maximum heights greater than 6 m with peak periods of 16 s over the fore reef. The larger event coincided with a peak spring tide, leading to energetic, highly skewed infragravity (0.04–0.004 Hz) and very low frequency (0.004–0.001 Hz) waves at the shoreline, which reached heights of 1.0 and 0.7 m, respectively. Water surface elevations, combined with wave runup, reached 3.7 m above the reef bed at the innermost reef flat adjacent to the toe of the beach, resulting in flooding of inland areas. This overwash occurred during a 3 h time window that coincided with high tide and maximum low-frequency reef flat wave heights. The relatively low-relief characteristics of this narrow reef flat may further drive shoreline amplification of low-frequency waves due to resonance modes. These results (1) demonstrate how the coupling of high offshore water levels with low-frequency reef flat wave energetics can lead to large impacts along fringing reef-lined shorelines, such as island overwash, and (2) lend support to the hypothesis that predicted higher sea levels will lead to more frequent occurrences of these extreme events, negatively impacting coastal resources and infrastructure.

  4. Research of high frequency link matrix rectifier based on current space vector predictive control%基于电流空间矢量预测控制的HFLMR研究

    Institute of Scientific and Technical Information of China (English)

    邓文浪; 齐庭庭; 李辉; 龙美志; 崔贵平; 毛勇; 郭有贵

    2013-01-01

      高频链矩阵整流器是一种新型的电力电子变换器,具有体积小、重量轻、转换级数少和可靠性高等特点。分析了高频链矩阵整流器的双极性空间矢量调制策略,提出了基于参考输入电流空间矢量的预测控制算法,建立了基于该预测控制算法的高频链矩阵整流器系统仿真模型。该预测控制算法具有计算量小,开关频率固定,可靠性高等特点,能实现高频链矩阵整流器输入侧电流正弦、单位输入功率因数和稳定的输出直流电流。仿真结果验证了所提控制策略的有效性。%High frequency link matrix rectifier is a new type power electronic converter with smaller size, lighter weight, less stages of conversion and high reliability, etc. The high frequency link matrix rectifier’s bipolar space vector modulation strategy is analyzed at first, and then a predictive control algorithm based on the referenced input current space vector is proposed. Based on the predictive control algorithm, the system simulation model of high frequency link matrix rectifier is established. The proposed predictive control algorithm shows the advantages of small computation, fixed switch frequency and high reliability, what’s more, it can realize sine waveform of input currents, unity input power factor and stable output DC current. Simulation results verify the effectiveness of the proposed control strategy. This work is supported by National Natural Science Foundation of China (No. 51277156 and No. 50977080).

  5. Scandinavian links

    DEFF Research Database (Denmark)

    Matthiessen, Christian Wichmann; Knowles, Richard D.

    2014-01-01

    centres, one joins more thinly populated regions, and the last one links peripheral areas. Two of them (The Great Belt Link and the Oresund Link) have been constructed and are in full operation. The third (the Fehmarnbelt Link) has been decided 2008 on bilateral government level. The three links...

  6. Application of Nanocrystalline Ribbon Curing Molding Iron Core in High Frequency Power Transformer%纳米晶薄带固化成型铁芯在中高频功率变压器上的应用

    Institute of Scientific and Technical Information of China (English)

    宋翀旸; 时红昊; 王立军; 杜宇

    2013-01-01

    The application of FeSiBCuNb nanocrystalline core curing method in power transformer and the influence on the performance of nanocrystalline power transformer core before and after molding of 24 μm and 30 μm different thickness of ribbons and curing agents are studied,it shows that 24μm ribbon can obtain lower loss,iron loss increased significantly after curing,permeability change little and meet the demand of the loss of existing core that with circular box work at 20 kHz,0.5 T less than 30 W/kg.Explore a new method of nanocrystalline power transformer core forming,provides more options for the design of the high frequency power transformer and the late line winding.%研究了FeSiBCuNb合金纳米晶铁芯固化成型方式在功率变压器上的应用,通过研究24μm和30 μm不同厚度带材、固化剂等对变压器铁芯成型前后性能的影响,结果表明,24μm带材可以获得更低的损耗,铁芯固化成型后损耗明显增加,导磁率变化不大,能够满足现有环形护盒铁芯在20 kHz,0.5T条件下损耗小于30 W/kg的要求,探索出新型的纳米晶功率变压器铁芯成型方式,为高频电源变压器的设计及后期线包的绕制提供了更多的选择方案.

  7. Frequency Transformation of Analog Filter Based on MATLAB%基于MATLAB的模拟滤波器的频率变换

    Institute of Scientific and Technical Information of China (English)

    赵普渡

    2012-01-01

    Under normal circumstances, filter design is only focused on lowpass filter, while by means of the frequency conversion technology the integration of high - pass, band - pass filter can work out any filter circuit except the low - pass. The use of MATLAB software greatly simplifies the actual calculation workload and verifies by simulation whether it can reach the expected design specifications. The article describes the frequency conversion of the analog filter and makes a simulative study respectively in the application of the software.%一般情况下,设计滤波器只着重研究低通滤波器,而高通、带通滤波器的综合要借助频率变换技术来实现低通以外各种滤波电路。MATLAB应用软件的使用大大简化了实际的计算工作量,并可以通过仿真来验证是否可以达到预期的设计指标。文章介绍了模拟滤波器的频率转换并运用软件实现了相应的仿真研究。

  8. The link in Linking

    Science.gov (United States)

    Caldwell, Jane C; Chiale, Pablo A; Gonzalez, Mario D; Baranchuk, Adrian

    2013-01-01

    We present 2 cases of the slow-fast form of AVNRT with initially narrow QRS complexes followed by sudden unexpected transition to persistently wide QRS complexes due to aberrant intraventricular conduction. Introduction of a properly timed extrastimulus in one case and critical oscillations in cycle length due to short-long coupling in the second case set the stage for the initial bundle branch block. However, persistence of the aberrancy pattern once the initial event abated was maintained by the "linking" phenomenon. Delayed, retrograde concealed activation from the contralateral bundle branch perpetuated the initial bundle branch block. PMID:23840106

  9. a partir de su respuesta en el dominio de la frecuencia. Estado mundial del arte. Parte I; Techniques of Diagnostic in Transformers from their Answer in Frequency Domain. World State of the Art. Part I

    Directory of Open Access Journals (Sweden)

    Orestes Hernández Areu

    2011-02-01

    Full Text Available Cada día cobra más importancia en el tema de los transformadores de potencia, la necesidad del diagnósticode los mismos y la detección de averías o anomalías que pudieran surgir durante su explotación. Existenmétodos para el diagnóstico de estos equipos, a través del llamado: Análisis de la respuesta en la frecuencia(FRA; en Cuba, aún no se ha introducido ninguna técnica de esta naturaleza, pero se comienzan ainvestigar sus potencialidades y posibilidades de introducción. Inicialmente se ha realizado un estudio delas fuentes que abordan este tema. En este artículo, se presenta la primera parte de un análisis que se harealizado del estado mundial del arte sobre las técnicas de diagnóstico en transformadores a partir de surespuesta  en  el  dominio  de  la  frecuencia,  específicamente  sobre  los  métodos  de  diagnóstico  detransformadores mediante el análisis de su respuesta en frecuencia, empleando la transformada rápida defourier (FFT.  Every day it gets paid more importance in the topic of the power transformers, the necessity of the diagnosisand the failures or anomalies detection than they could arise during their exploitation.  Methods exist for thediagnosis of these equipments, through the called frequency response analysis (FRA; in Cuba, techniquesof this nature has not still been introduced, but begins to investigate its potentialities and introductionpossibilities. As beginning of this investigation process, has been carried out a study of the sources thatapproach this topic. In this article, is presented the first part of an analysis that has been carried out aboutthe state of the world art on techniques of diagnostic of transformers from its frequency domain response.This part is about those methods of diagnostic of transformers by means of the analysis of their frequencyresponse, using the fast fourier transformed (FFT.

  10. Repeated games and direct reciprocity under active linking.

    Science.gov (United States)

    Pacheco, Jorge M; Traulsen, Arne; Ohtsuki, Hisashi; Nowak, Martin A

    2008-02-21

    Direct reciprocity relies on repeated encounters between the same two individuals. Here we examine the evolution of cooperation under direct reciprocity in dynamically structured populations. Individuals occupy the vertices of a graph, undergoing repeated interactions with their partners via the edges of the graph. Unlike the traditional approach to evolutionary game theory, where individuals meet at random and have no control over the frequency or duration of interactions, we consider a model in which individuals differ in the rate at which they seek new interactions. Moreover, once a link between two individuals has formed, the productivity of this link is evaluated. Links can be broken off at different rates. Whenever the active dynamics of links is sufficiently fast, population structure leads to a simple transformation of the payoff matrix, effectively changing the game under consideration, and hence paving the way for reciprocators to dominate defectors. We derive analytical conditions for evolutionary stability.

  11. Disc piezoelectric ceramic transformers.

    Science.gov (United States)

    Erhart, Jirií; Půlpán, Petr; Doleček, Roman; Psota, Pavel; Lédl, Vít

    2013-08-01

    In this contribution, we present our study on disc-shaped and homogeneously poled piezoelectric ceramic transformers working in planar-extensional vibration modes. Transformers are designed with electrodes divided into wedge, axisymmetrical ring-dot, moonie, smile, or yin-yang segments. Transformation ratio, efficiency, and input and output impedances were measured for low-power signals. Transformer efficiency and transformation ratio were measured as a function of frequency and impedance load in the secondary circuit. Optimum impedance for the maximum efficiency has been found. Maximum efficiency and no-load transformation ratio can reach almost 100% and 52 for the fundamental resonance of ring-dot transformers and 98% and 67 for the second resonance of 2-segment wedge transformers. Maximum efficiency was reached at optimum impedance, which is in the range from 500 Ω to 10 kΩ, depending on the electrode pattern and size. Fundamental vibration mode and its overtones were further studied using frequency-modulated digital holographic interferometry and by the finite element method. Complementary information has been obtained by the infrared camera visualization of surface temperature profiles at higher driving power.

  12. The Successive Mean Quantization Transform

    OpenAIRE

    Nilsson, Mikael; Dahl, Mattias; Claesson, Ingvar

    2005-01-01

    This paper presents the Successive Mean Quantization Transform (SMQT). The transform reveals the organization or structure of the data and removes properties such as gain and bias. The transform is described and applied in speech processing and image processing. The SMQT is considered as an extra processing step for the mel frequency cepstral coefficients commonly used in speech recognition. In image processing the transform is applied in automatic image enhancement and dynamic range compress...

  13. The Successive Mean Quantization Transform

    OpenAIRE

    Nilsson, Mikael; Dahl, Mattias; Claesson, Ingvar

    2005-01-01

    This paper presents the Successive Mean Quantization Transform (SMQT). The transform reveals the organization or structure of the data and removes properties such as gain and bias. The transform is described and applied in speech processing and image processing. The SMQT is considered as an extra processing step for the mel frequency cepstral coefficients commonly used in speech recognition. In image processing the transform is applied in automatic image enhancement and dynamic range compress...

  14. Early nuclear alterations and immunohistochemical expression of Ki-67, Erb-B2, vascular endothelial growth factor (VEGF), transforming growth factor (TGF-beta1) and integrine-linked kinase (ILK) two days after tamoxifen in breast carcinoma.

    Science.gov (United States)

    Morena, A M L; Oshima, C T F; Gebrim, L H; Egami, M I; Silva, M R R; Segreto, R A; Giannotti Filho, O; Teixeira, V P C; Segreto, H R C

    2004-01-01

    The purpose of the present study was to evaluate breast carcinoma samples before and two days after treatment with tamoxifen in order to analyse early histopathological alterations--particularlynuclear alterations-- as well as immunohistochemical expression of Ki-67, Erb-B2, VEGF, TGF-beta1 and ILK proteins. Twenty one cases of invasive ductal and lobular breast carcinoma were studied. Patients were submitted to biopsy of the lesion and, after confirmation of the diagnosis, they received 20 mg of tamoxifen a day, beginning two days before surgery. The samples obtained during biopsy and after surgery were stained with HE for histopathological diagnosis. Estrogen receptor was positive in 18 cases and negative in 3. The immunohistochemical method was applied for the detection of Ki-67, Erb-B2, protein, vascular endothelial growth factor (VEGF), transforming growth factor beta (TGF-beta1) and integrin linked kinase (ILK). Two days after tamoxifen treatment, the following results were observed: 1) decrease in the cell volume, chomatine condensation, nucleoli less evident and clearly defined nuclear limits; 2) significant reduction in the expression of Erb-B2 protein and significant increase in the expression of TGF-beta1 protein; 3) expression of others proteins (Ki-67, VEGF and ILK) was not altered during the indicated time frame. Our results suggest that analyzing nuclear alterations and expression of Erb-B2 and TGF-beta1 proteins would be useful to assess the initial response to tamoxifen.

  15. Femtosecond nonlinear spectroscopy at surfaces: Second-harmonic probing of hole burning at the Si(111)7x7 surface and fourier-transform sum-frequency vibrational spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    McGuire, John Andrew [Univ. of California, Berkeley, CA (United States)

    2004-11-24

    The high temporal resolution and broad bandwidth of a femtosecond laser system are exploited in a pair of nonlinear optical studies of surfaces. The dephasing dynamics of resonances associated with the adatom dangling bonds of the Si(111)7 x 7 surface are explored by transient second-harmonic hole burning, a process that can be described as a fourth-order nonlinear optical process. Spectral holes produced by a 100 fs pump pulse at about 800 nm are probed by the second harmonic signal of a 100 fs pulse tunable around 800 nm. The measured spectral holes yield homogeneous dephasing times of a few tens of femtoseconds. Fits with a Lorentzian spectral hole centered at zero probe detuning show a linear dependence of the hole width on pump fluence, which suggests that charge carrier-carrier scattering dominates the dephasing dynamics at the measured excitation densities. Extrapolation of the deduced homogeneous dephasing times to zero excitation density yields an intrinsic dephasing time of {approx} 70 fs. The presence of a secondary spectral hole indicates that scattering of the surface electrons with surface optical phonons at 570 cm-1 occurs within the first 200 fs after excitation. The broad bandwidth of femtosecond IR pulses is used to perform IR-visible sum frequency vibrational spectroscopy. By implementing a Fourier-transform technique, we demonstrate the ability to obtain sub-laser-bandwidth spectral resolution. FT-SFG yields a greater signal when implemented with a stretched visible pulse than with a femtosecond visible pulse. However, when compared with multichannel spectroscopy using a femtosecond IR pulse but a narrowband visible pulse, Fourier-transform SFG is found to have an inferior signal-to-noise ratio. A mathematical analysis of the signal-to-noise ratio illustrates the constraints on the Fourier-transform approach.

  16. Fiber-wireless transmission system of 108  Gb/sdata over 80 km fiber and 2×2multiple-input multiple-output wireless links at 100 GHz W-band frequency.

    Science.gov (United States)

    Li, Xinying; Dong, Ze; Yu, Jianjun; Chi, Nan; Shao, Yufeng; Chang, G K

    2012-12-15

    We experimentally demonstrate a seamlessly integrated fiber-wireless system that delivers a 108  Gb/s signal through 80 km fiber and 1 m wireless transport over free space at 100 GHz adopting polarization-division-multiplexing quadrature-phase-shift-keying (PDM-QPSK) modulation and heterodyning coherent detection. The X- and Y-polarization components of the optical PDM-QPSK baseband signal are simultaneously upconverted to 100 GHz wireless carrier by optical polarization-diversity heterodyne beating, and then independently transmitted and received by two pairs of transmitter and receiver antennas, which form a 2×2 multiple-input multiple-output wireless link. At the wireless receiver, two-stage downconversion is performed firstly in the analog domain based on balanced mixer and sinusoidal radio frequency signal, and then in the digital domain based on digital signal processing (DSP). Polarization demultiplexing is realized by the constant modulus algorithm in the DSP part at the receiver. The bit-error ratio for the 108  Gb/s PDM-QPSK signal is less than the pre-forward-error-correction threshold of 3.8×10(-3) after both 1 m wireless delivery at 100 GHz and 80 km single-mode fiber-28 transmission. To our knowledge, this is the first demonstration to realize 100  Gb/s signal delivery through both fiber and wireless links at 100 GHz.

  17. Analysis of the Effect of Carrier Frequency Offset on the Performance of Transform Domain Communication System%载波频率偏差对变换域通信系统性能的影响分析

    Institute of Scientific and Technical Information of China (English)

    王舒; 达新宇; 褚振勇; 谢铁城; 邹维

    2012-01-01

    Considering the situation that the received signals magnitude is decreased and inter-carrier interference (ICI) is induced by the carrier frequency offsets (CFO) , through establishing mathematical model, the analytical expression for the Bit Error Rate (BER) , which is derived from Transform Domain communication system (TDCS) , is obtained. Furthermore, the relationships between the BER and the correlated parameters are studied, as well as, the Signal Noise Ratio (SNR) loss. Finally, the analysis conclusions are verified by the simulation, the simulation result agrees well with the analysis conclusion. The quantitative analysis of the system performance caused by the frequency error of carrier is given. These researches illustrate that the frequency offset affect the BER performance seriously and there is error floor on the BER when the normalized frequency offset is more than 0. 6. To keep the system work around, the normalized frequency offset has to be less than 0. 05.%针对载波频率偏差导致变换域通信系统的接收信号幅度下降并产生载波间干扰的问题,通过建立系统模型,推导出了载波频偏存在情况下系统误码率的解析式,在此基础上,分析了子载波个数、频谱使用率以及载波频偏与系统输出信噪比的关系,以信噪比损失为度量,定量地给出了载波频偏对系统性能的影响,最后进行了仿真验证,仿真结果与数值分析高度吻合.仿真结果表明:频偏显著影响系统性能,且归一化载波频偏大于0.6时与误码率之间会出现地板效应;为避免系统性能恶化,归一化频偏应控制在0.05的范围内.

  18. Transformer Impedance Reflection Demonstration

    Science.gov (United States)

    Layton, William

    2014-01-01

    Questions often arise as to how a device attached to a transformer can draw power from the electrical power grid since it seems that the primary and secondary are not connected to one another. However, a closer look at how the primary and secondary are linked together magnetically and a consideration of the role of Lenz's law in this linkage…

  19. Education as Habitus Transformations

    Science.gov (United States)

    von Rosenberg, Florian

    2016-01-01

    Unlike a conventional reading of Bourdieu, this article focuses on his work with regard to the transformation of social structure. In the context of a rereading, from an educational theory perspective, the article proposes an approach that allows for the linking of empirically informed social theory, on the one hand, and biography research…

  20. Transformer Impedance Reflection Demonstration

    Science.gov (United States)

    Layton, William

    2014-01-01

    Questions often arise as to how a device attached to a transformer can draw power from the electrical power grid since it seems that the primary and secondary are not connected to one another. However, a closer look at how the primary and secondary are linked together magnetically and a consideration of the role of Lenz's law in this linkage…

  1. 工频电磁场对变电站作业人员体液免疫功能影响研究%Effects of exposure to power frequency electromagnetic fields on humoral immune function in transformer substation workers

    Institute of Scientific and Technical Information of China (English)

    黎丽春; 闫雪华; 陈慧峰; 温薇; 李丽; 李华亮; 莫平

    2016-01-01

    Objective To explore the effects of long-term exposure to power frequency electromagnetic fields on the humoral immune function in transformer substation workers.Methods By simple random sampling method, 64 workers with length of service longer than 5.0 years in 500 kV transformer substation were chosen as exposure group and 57 general administrative staffs without exposure to power frequency electromagnetic field were chosen as control group.Venous blood was collected from subjects of these two groups and the levels of immunoglobulin ( Ig) A, IgG, IgM, complement ( C) 3 and C4 in plasma were examined by immunoturbidimetry.Results Compared with the control group, the levels of both IgA and IgG increased (P10.0 years.Conclusion Long-term exposure to power frequency electromagnetic fields may activate the humoral immune function in transformer substation workers.%目的:探讨长期接触工频电磁场对变电站作业人员体液免疫功能的影响。方法以单纯随机抽样方法抽取64名工龄5.0年以上的在500 kV变电站从事工频电磁场作业的人员为接触组,以57名无职业性接触工频电磁场的供电局后勤行政人员为对照组。采集2组人员肘静脉血,采用免疫比浊法测定血浆中免疫球蛋白( Ig) A、IgG、IgM、补体3和补体4水平。结果与对照组比较,接触组人群血浆中IgA和IgG水平均升高( P<0.05),补体3和补体4水平均下降(P<0.05)。与对照组比较,接触组工龄≤10.0年亚组人群血浆中IgG水平升高(P<0.05),补体3和补体4水平均下降(P<0.05);接触组工龄>10.0年亚组人群血浆中补体4水平下降(P<0.05)。结论长期职业性接触工频电磁场可能对作业人群体液免疫功能产生一定的激活作用。

  2. Comparative assessment of power control of axial blowers for condensers and recirculation coolers: Phase control, frequency control, transformers, EC; Vergleich der Leistungsregelung von Axialventilatoren fuer Verfluessiger und Rueckkuehler: Phasenanschnittregler, Frequenzumformer, Transformatoren, EC Technik

    Energy Technology Data Exchange (ETDEWEB)

    Hubert, G. [Hans Guentner GmbH, Fuerstenfeldbruck (Germany)

    2003-07-01

    The currently available control technologies were compared. Power consumption and sound emission were measured and evaluated. The blower with asynchronous motor was operated with and without noise filter, transformer and electronic frequency inverter with sinus filter. The blower with electronically commuted d.c. motor had an integrated power electronics for direct variable-speed operation connected to the three-phase current network. The electric power consumption was measured at 7-100 percent of the air volume flow pumped by the condenser. This provides reliable data not only for rated operation but also across the whole range of air flow rates and enables a better comparison. The sound measurements also cover the whole range of air volume flow and comprise both the air and the controller noise. The summed-up sound pressure levels are compared. The results give planners and constructors valuable information for selecting the appropriate power control system. (orig.) [German] Die Vielfalt der eingesetzten Geraete fuer die Stetigregelung von Verfluessiger mit Axialventilatoren ist gross. Um klare Aussagen zu den jeweiligen Regelprinzipien zu gewinnen wurden die zur Zeit technisch verfuegbaren Loesungen im Versuch gegenuebergestellt. Die relevanten Groessen Leistungsaufnahme und Schallemission wurden messtechnisch ermittelt und ausgewertet. Der Ventilator mit Asynchron-Motor wurde vergleichsweise mit Phasenausschnitt ohne und mit Geraeuschfilter, Transformator und elektronischem Frequenzumformer mit Sinusfilter betrieben. Der Ventilator mit elektronisch kommutiertem Gleichstrommotor hatte eine integrierte Leistungselektronik, die den direkten Betrieb mit variabler Drehzahl am Drehstromnetz ermoeglicht. Gemessen wurden die elektrischen Aufnahmeleistungen im Bereich von 7 bis 100% des durch den Verfluessiger gefoerderten Luftvolumenstromes. So hat man fundierte Werte nicht nur im Nennbetriebspunkt sondern auch ueber den gesamten Luftfoerderbereich und kann sie

  3. Comparative Analysis on Three Kinds of Combined DC-DC Converter Mode Inverters with High Frequency Link%三类组合直流变换器型高频环节逆变器的分析比较

    Institute of Scientific and Technical Information of China (English)

    陈艳慧; 陈道炼

    2012-01-01

    The combined DC-DC converter mode inverters with high frequency link is composed of two same isolated bi-directional DC-DC converters which are connected in parallel on the input side and reversely connected in series on the output side including Buck, Boost, and Buck-Boost mode. The circuit topology, control strategy, input current ripple, output voltage ripple, key parameters and test waveforms of three kinds of inverter were comparatively studied and an important conclusion was obtained.%组合直流变换器型高频环节逆变器是由两个相同的隔离双向直流变换器输入侧并联、输出侧反向串联构成,包括Buck、Boost、Buck-Boost型三类。主要对Buck、Boost、Buck-Boost组合直流变换器型高频环节逆变器的电路拓扑、控制策略、输入电流纹波、输出电压纹波、关键电路参数、原理实验波形等方面进行了比较研究,获得了重要结论。

  4. 光伏系统单相高频链正弦波逆变器的拓扑研究%Research on Topology of Single-phase High Frequency Link Sine Wave Inverter in Photovoltaic System

    Institute of Scientific and Technical Information of China (English)

    冀玉丕; 谢运祥

    2012-01-01

    归纳与分类了近年提出的多种应用于可再生能源以及光伏发电系统的单相高频链正弦波逆变器拓扑结构,概括与讨论了各种变换器拓扑的优点、缺点,总结了DC/AC逆变器应用于光伏发电系统所面临的技术要求、挑战以及有可能采用的新技术,为研究、开发下一代高性能DC/AC逆变器提供了技术参考.%The paper induced and classified the advantage and disadvantage of various high frequency link sine wave inverter topology generally, which is applied to renewable and photovoltaic generating system recently. In addition, it summarized the technical requirement and challenge and new technology probably applied of DC/AC inverter which is applied in photovoltaic generating system, which provides the technical reference for the research and development of next generation high performance.

  5. Link Clustering with Extended Link Similarity and EQ Evaluation Division.

    Directory of Open Access Journals (Sweden)

    Lan Huang

    Full Text Available Link Clustering (LC is a relatively new method for detecting overlapping communities in networks. The basic principle of LC is to derive a transform matrix whose elements are composed of the link similarity of neighbor links based on the Jaccard distance calculation; then it applies hierarchical clustering to the transform matrix and uses a measure of partition density on the resulting dendrogram to determine the cut level for best community detection. However, the original link clustering method does not consider the link similarity of non-neighbor links, and the partition density tends to divide the communities into many small communities. In this paper, an Extended Link Clustering method (ELC for overlapping community detection is proposed. The improved method employs a new link similarity, Extended Link Similarity (ELS, to produce a denser transform matrix, and uses the maximum value of EQ (an extended measure of quality of modularity as a means to optimally cut the dendrogram for better partitioning of the original network space. Since ELS uses more link information, the resulting transform matrix provides a superior basis for clustering and analysis. Further, using the EQ value to find the best level for the hierarchical clustering dendrogram division, we obtain communities that are more sensible and reasonable than the ones obtained by the partition density evaluation. Experimentation on five real-world networks and artificially-generated networks shows that the ELC method achieves higher EQ and In-group Proportion (IGP values. Additionally, communities are more realistic than those generated by either of the original LC method or the classical CPM method.

  6. Comparative investigation of power control of axial blowers for liquefiers and recirculation coolers: Phase controller, frequency converter, transformers, EC technology; Vergleich der Leistungsregelung von Axialventilatoren fuer Verfluessiger und Rueckkuehler: Phasenanschnittregler, Frequenzumformer, Transformatoren, EC Technik

    Energy Technology Data Exchange (ETDEWEB)

    Hubert, G. [Hans Guentner GmbH, Fuerstenfeldbruck (Germany)

    2003-07-01

    Phase controllers are well suited for liquefaction pressure control, and energy savings are higher than with blower shut-off. They emit noise in the 300 Hz range and need an additional acoustic filter if noise reduction in part-load operation is required. Frequency controllers with all-terminal sinusoid filters have a higher saving potential at 40-80 percent of the volume flow as compared to phase controllers. Noise is significantly lower than in phase controllers, even with acoustic filters. The best performance was obtained with EC technology, which had the highest energy savings and noise levels similar to transformer control, which was hitherto considered to be the best option. (orig.) [German] Phasenanschnittregler sind zur Verfluessigungsdruckregelung gut geeignet und bieten ein groesseres Energieeinsparpotential als die Methode der Ventilatorabschaltung. Wenn die Schallreduzierung im Teillastbereich wichtig ist, sind sie wegen der stoerend wirkenden 300 Hz Tonanteilen nicht geeignet. Hier kann ein zusaetzlicher Geraeuschfilter groesstenteils Abhilfe schaffen. Frequenzregler mit allpoligem Sinusfilter haben deutliche Einsparpotentiale im Bereich von 40% bis 80% des Volumenstroms gegenueber den Phasenanschnittreglern. Die Schallreduzierung wirkt bis in die unteren Drehzahlbereiche und liegt deutlich unter den Werten der Phasenanschnittsteuerung mit Geraeuschfilter. Den hoechsten Gesamtwirkungsgrad ueber den ganzen Luftfoerderbereich liefert die getestete EC-Technik. In allen Betriebspunkten ist somit die hoechste Energieersparnis gegeben. Die Schallreduzierung ist gleichwertig mit den Ergebnissen der Transformatorregelung, die bisher als geraeuschlos bestes Verfahren eingesetzt wurde. (orig.)

  7. Design of Self-adaptive Damping Controller to Low Frequency Power Oscillation in Interconnected Power Systems Based on Variable Frequency Transformer%基于变频变压器的电力系统低频振荡自适应阻尼控制器设计

    Institute of Scientific and Technical Information of China (English)

    陈葛松; 周孝信; 宋瑞华

    2011-01-01

    Variable frequency transformer (VFT) is a new type of flexible AC transmission systems (FACTS) device for interconnecting power systems asynchronously. In this paper, the basic structure and functions of VFT were introduced, the performance of VFT to damp low frequency power oscillation was studied, and a new type of self-adaptive damping controller including system model and calculation program was developed by means of VFT and Prony method. Two simulation systems respective for a typical 4 generators power system and a complex practical power system with VFT devices were build up by means of power system analysis software package (PSASP), and the adaptivity and efficiency of self-adaptive damping controller were tested and verified with carefully studied under different conditions.%变频变压器(variable frequency transformer,VFT)是一种能够联接异步电网的新型灵活交流输电系统设备.介绍了变频变压器的基本结构和主要功能,重点分析如何利用变频变压器抑制电力系统低频功率振荡,开发了基于变频变压器和普罗尼(Prony)方法的电力系统低频功率振荡自适应阻尼控制器的系统模型和计算程序.利用电力系统综合分析程序建立了包括变频变压器在内的典型4机电力系统和大型实际复杂电力系统的仿真模型,对不同系统规模、不同结构情况下阻尼控制器抑制低频振荡的效果进行大量仿真研究,验证了自适应阻尼控制器的适应性和有效性.

  8. Communication Links

    OpenAIRE

    2003-01-01

    This interactive tutorial helps learners to: Identify key upward, lateral, downward, and informal communication links in their organizations. , Reflect on the benefits, control, satisfaction, information filters, and feedback mechanism of various communication links in the organizations. OCL1000 Communicating Change in Complex Organizations

  9. Operative links

    DEFF Research Database (Denmark)

    Wistoft, Karen

    2010-01-01

    as networks: second, a semantic perspective on discourses and concepts of health, and, third, a health pedagogical perspective on participation, intervention, and roles. This paper argues for the importance of 'operative links' between different levels in health strategies. It is proposed that such links...

  10. Hadamard Transforms

    CERN Document Server

    Agaian, Sos; Egiazarian, Karen; Astola, Jaakko

    2011-01-01

    The Hadamard matrix and Hadamard transform are fundamental problem-solving tools in a wide spectrum of scientific disciplines and technologies, such as communication systems, signal and image processing (signal representation, coding, filtering, recognition, and watermarking), digital logic (Boolean function analysis and synthesis), and fault-tolerant system design. Hadamard Transforms intends to bring together different topics concerning current developments in Hadamard matrices, transforms, and their applications. Each chapter begins with the basics of the theory, progresses to more advanced

  11. 准单级单向Buck直流变换器型高频链并网逆变器%Quasi single-stage unidirectional Buck DC-DC converter mode grid-connected inverters with high frequency link

    Institute of Scientific and Technical Information of China (English)

    陈道炼; 严斌; 陈峰; 左巧安; 林真

    2012-01-01

    A circuit configuration and circuit topological family of quasi single-stage unidirectional buck dc-dc converter mode grid-connected inverters with high frequency link are proposed in this paper. Its circuit configuration is composed of the unidirectional isolated buck dc-dc converter and polarity reversal inverting bridge, and its circuit topology includes single-transistor forward, interleaving single-transistor forward, push-pull, push-pull forward, two-transistor forward, interleaving two-transistor forward, half-bridge, and full-bridge mode circuit. The circuit topology, instantaneous current control strategy, steady principle properties, and design criteria for the key circuit parameters were deeply investigated. Taking push-pull forward mode topology as an example, 1 kW 48VDC/220V50 HzAC grid-connected inverter prototype was developed. The research results show that this kind of inverter has the advantages such as high frequency electrical isolation, simple topology, quasi single-stage conversion, high conversion efficiency , the polarity reversal inverting bridge' s power switches having low voltage stress and ZVZCS, high quality grid-connected current etc.%提出准单级单向Buck直流变换器型高频链并网逆变器电路结构与拓扑族.其电路结构是由单向隔离Buck直流变换器和极性反转逆变桥级联构成;其拓扑族包括推挽正激式、双管正激式、并联交错双管正激式、半桥式和全桥式电路.深入分析研究类逆变器的电路拓扑、电流瞬时值控制策略、稳态原理特性和关键电路参数设计准则.以推挽正激式拓扑为例,设计并研制出1kW48VDC/220V50HzAC并网逆变器样机.研究结果表明,此类逆变器具有高频电气隔离、电路结构简洁、准单级功率变换、变换效率高、极性反转逆变桥功率开关电压应力低且为ZVZCS、并网电流质量高等优点.

  12. Time-Frequency Analysis for Full Waveform Characteristics of Acoustic Logging Based on Fractal Fourier Transform%基于分数阶Fourier变换的声波测井全波列特征时频分析

    Institute of Scientific and Technical Information of China (English)

    王祝文; 向旻; 刘菁华; 王晓丽; 张雪昂; 杨闯

    2012-01-01

    目前,阵列声波测井信号处理大多在时间域或频率域中进行.但是,单纯的时间域或频率域方法有很大的局限性.为了打破这些局限性,笔者将分数阶Fourier变换方法用于阵列声波测井信号的分析之中,研究了不同性质储集层中信号幅度随分数阶Fourier变换阶数变化的规律.实验结果表明:在干层,幅度呈“1”型分布;在水层,幅度呈“Y”型分布,“Y”的两支开口较小,在阶数大于0.3的区域中,幅度较大;在油层,幅度呈“Y”型分布,“Y”的两支开口较大,在阶数大于0.6的区域中,幅度较大.因此,分数阶Fourier变换在提取阵列声波测井蕴含的储集层流体性质信息方面具有很好的前景.%As we knew, most of the process techniques for array acoustic logging data still use the analysis methods only in either time domain or frequency domain, but these methods all have obvious limitation for signal analysis. In order to break these limitations, the authors used the fratal Fourier for analysing the array acoustic logging signals and researching the law of signal amplitude variation with the order of the fratal Fourier transform variation in different kinds of reservoirs. As the results, in the dry formation, amplitude shows "1" type distribution; In water formation, amplitude shows "Y" type distribution, two branch of "Y" open narrow and in area of order greater than 0. 3, amplitude is larger; In oil formation, amplitude shows "Y" type distribution, two branch of "Y" open wide and in area of order greater than 0. 6, amplitude is larger. So the fratal Fourier transform have very good prospect for extracting the reservoir liquid properties information embedded in the array acoustic logging data.

  13. Power Electronic Transformer based Three-Phase PWM AC Drives

    Science.gov (United States)

    Basu, Kaushik

    A Transformer is used to provide galvanic isolation and to connect systems at different voltage levels. It is one of the largest and most expensive component in most of the high voltage and high power systems. Its size is inversely proportional to the operating frequency. The central idea behind a power electronic transformer (PET) also known as solid state transformer is to reduce the size of the transformer by increasing the frequency. Power electronic converters are used to change the frequency of operation. Steady reduction in the cost of the semiconductor switches and the advent of advanced magnetic materials with very low loss density and high saturation flux density implies economic viability and feasibility of a design with high power density. Application of PET is in generation of power from renewable energy sources, especially wind and solar. Other important application include grid tied inverters, UPS e.t.c. In this thesis non-resonant, single stage, bi-directional PET is considered. The main objective of this converter is to generate adjustable speed and magnitude pulse width modulated (PWM) ac waveforms from an ac or dc grid with a high frequency ac link. The windings of a high frequency transformer contains leakage inductance. Any switching transition of the power electronic converter connecting the inductive load and the transformer requires commutation of leakage energy. Commutation by passive means results in power loss, decrease in the frequency of operation, distortion in the output voltage waveform, reduction in reliability and power density. In this work a source based partially loss-less commutation of leakage energy has been proposed. This technique also results in partial soft-switching. A series of converters with novel PWM strategies have been proposed to minimize the frequency of leakage inductance commutation. These PETs achieve most of the important features of modern PWM ac drives including 1) Input power factor correction, 2) Common

  14. Triple-frequency inductive voltage withstand test of electromagnetic voltage transformer for 110 kV GIS%110kV GIS电磁式电压互感器三倍频感应耐压试验

    Institute of Scientific and Technical Information of China (English)

    肖勇; 潘翀; 杨帆; 罗绪东; 蔡川

    2011-01-01

    The AC voltage withstand test is applied to detect the insulation defects of EVT (Electromagnetic Voltage Transformer) in GIS. Two kinds of on-site triple-frequency test methods are presented with test wiring diagrams and test procedures. The voltage input and the compensating reactor are connected to different windings of EVT in the first method while to the same winding in the second method. The cause of capacitive voltage-augment and its influence,the necessity of no-load test and the determination of voltage withstand test duration are analyzed by calculation and compared between two methods. The results of field triple-frequency inductive voltage withstand test indicate the relationship among primary current, secondary current and compensating reactance, showing the first method is more suitable for EVT in GIS.%为了发现气体绝缘的全封闭组合电器(GIS)中电磁式电压互感器(EVT)的某些绝缘缺陷,需要进行交流耐压试验.提出了110 kV GIS中EVT通过三倍频感应耐压的2种现场试验方法、试验接线及操作步骤,第1种感应耐压方案为EVT的二次绕组端子上的加压侧与补偿侧不同,第2种感应耐压方案为加压侧与补偿侧并联.通过计算,分析了试验中出现容升电压的原因及影响、空载试验的必要性及耐压时间的选定,比较了采用2种不同补偿方式的差异.现场试验结果表明EVT三倍频感应耐压时一次侧电流、二次侧电流与补偿电抗量的规律,说明第1种感应耐压方案较适用于GIS中EVT的感应耐压.

  15. Pragmatic circuits frequency domain

    CERN Document Server

    Eccles, William

    2006-01-01

    Pragmatic Circuits: Frequency Domain goes through the Laplace transform to get from the time domain to topics that include the s-plane, Bode diagrams, and the sinusoidal steady state. This second of three volumes ends with a-c power, which, although it is just a special case of the sinusoidal steady state, is an important topic with unique techniques and terminology. Pragmatic Circuits: Frequency Domain is focused on the frequency domain. In other words, time will no longer be the independent variable in our analysis. The two other volumes in the Pragmatic Circuits series include titles on DC

  16. Link Analysis

    Science.gov (United States)

    Donoho, Steve

    Link analysis is a collection of techniques that operate on data that can be represented as nodes and links. This chapter surveys a variety of techniques including subgraph matching, finding cliques and K-plexes, maximizing spread of influence, visualization, finding hubs and authorities, and combining with traditional techniques (classification, clustering, etc). It also surveys applications including social network analysis, viral marketing, Internet search, fraud detection, and crime prevention.

  17. Properties and convergence analysis of FMmlet transform

    Institute of Scientific and Technical Information of China (English)

    戴琼海; 邹红星; 刘智新; 王殿军; 李衍达

    2002-01-01

    The linearity,time shifting,time scaling,and time inversion properties of FMmlet transform are proved,and the frequency shifting property of one of the subspaces of FMmlet transform,namely the chirplet transform is presented.Moreover,it is proved that in the process of FMm let based atomic signal decomposition,the residual signals decay exponentially.``

  18. Nonlocal transformation optics

    CERN Document Server

    Castaldi, Giuseppe; Alu', Andrea; Engheta, Nader

    2011-01-01

    We show that the powerful framework of transformation optics may be exploited for engineering the nonlocal response of artificial electromagnetic materials. Relying on the form-invariant properties of coordinate-transformed Maxwell's equations in the spectral domain, we derive the general constitutive "blueprints" of transformation media yielding prescribed nonlocal field-manipulation effects, and provide a physically-incisive and powerful geometrical interpretation in terms of deformation of the equi-frequency contours. In order to illustrate the potentials of our approach, we present an example of application to a wave-splitting refraction scenario, which may be implemented via a simple class of artificial materials. Our results provide a systematic and versatile framework which may open intriguing venues in dispersion engineering of artificial materials.

  19. Optimization of Optically Preamplified Inter-Satellite Microwave Photonics Links with Two Radio-Frequency Signals Input%两路输入前置光放大星间微波光子链路优化

    Institute of Scientific and Technical Information of China (English)

    朱子行; 赵尚弘; 赵辉; 李勇军; 楚兴春; 蒋炜; 侯睿; 王翔; 赵顾颢

    2013-01-01

    考虑到星间微波光子链路传输损耗大且多路微波信号之间交调干扰严重,利用前置光放大来提高链路的信号噪声失真比RSNDR.建立了两路输入前置光放大星间微波光子链路模型,推导出了RSNDR的解析表达式.通过优化马赫-曾德尔调制器的直流偏置相移,使得在给定输入射频信号功率条件下RSNDR最大,并进一步分析了前置光放大器参数对最优直流偏置相移和RSNDR的影响.仿真结果表明,前置光放大改变了影响RSNDR的主要因素,使信号放大的倍数大于噪声和三阶交调(IM3)放大的倍数,从而提高了链路的RSNDR.当前置光放大器增益为20 dB、噪声系数为3 dB时,最优的RSNDR比不加前置光放大器时提高24 dB.前置光放大器增益和噪声系数对最优的RSNDR影响很大,而对最优的直流偏置相移几乎无影响.%An optical preamplifier is utilized to improve the signal-to-noise and distortion ratio .RSNDR of inter-satellite microwave photonics links considering the large signal losses in distant propagation and serious deterioration caused by inter-modulation distortion. An optically preamplified inter-satellite microwave photonics links model with two radio-frequency (RF) signals input is established and an analytical expression of .RSNDR is derived. The direct current (DC) bias phase shift of modulator can be optimized so as to maximize the .RSNDR given the desired input RF signal power, and the effects of the optical preamplifier parameters on the optimum DC bias phase shift and .RSNDR are also examined. Simulation results show that the most limitative factors degrading the .RSNDR are changed, and the fundamental power is seen to increase more compared with the power of third-order intermodulation (IM3) plus noise due to optical preamplifier. Thus, .RSNDR can be improved with respect to the case of non-optical preamplifier. For the preamplifier gain of 20 dB and noise figure of 3 dB, an improvement of about

  20. Organelle transformation.

    Science.gov (United States)

    Bhattacharya, Anjanabha; Kumar, Anish; Desai, Nirali; Parikh, Seema

    2012-01-01

    The source of genetic information in a plant cell is contained in nucleus, plastids, and mitochondria. Organelle transformation is getting a lot of attention nowadays because of its superior performance over the conventional and most commonly used nuclear transformation for obtaining transgenic lines. Absence of gene silencing, strong predictable transgene expression, and its application in molecular pharming, both in pharmaceutical and nutraceuticals, are some of many advantages. Other important benefits of utilizing this technology include the absence of transgene flow, as organelles are maternally inherited. This may increase the acceptability of organelle transformation technology in the development of transgenic crops in a wider scale all over the globe. As the need for crop productivity and therapeutic compounds increases, organelle transformation may be able to bridge the gap, thereby having a definite promise for the future.

  1. Visualizing Transformation

    DEFF Research Database (Denmark)

    Pedersen, Pia

    2012-01-01

    Transformation, defined as the step of extracting, arranging and simplifying data into visual form (M. Neurath, 1974), was developed in connection with ISOTYPE (International System Of TYpographic Picture Education) and might well be the most important legacy of Isotype to the field of graphic...... design. Recently transformation has attracted renewed interest because of the book ‘The Transformer’ written by Robin Kinross and Marie Neurath. My on-going research project, summarized in this paper, identifies and depicts the essential principles of data visualization underlying the process...... of transformation with reference to Marie Neurath’s sketches on the Bilston Project. The material has been collected at the Otto and Marie Neurath Collection housed at the University of Reading, UK. By using data visualization as a research method to look directly into the process of transformation the project...

  2. Transformational leadership.

    Science.gov (United States)

    Luzinski, Craig

    2011-12-01

    This month, the director of the Magnet Recognition Program® takes an in-depth look at the Magnet® model component transformational leadership. The author examines the expectations for Magnet organizations around this component. What are the qualities that make a nursing leader truly transformational, and what is the best approach to successfully lead a healthcare organization through today's volatile healthcare environment?

  3. Landskabets transformation

    DEFF Research Database (Denmark)

    Munck Petersen, Rikke

    2005-01-01

    Seminaroplæg fra forskere. Faglige seminarer på KA, forår 2005. Belyser transformation af det danske landskab fysisk som holdningsmæssigt, samt hvordan phd-arbejdets egen proces håndterer den.......Seminaroplæg fra forskere. Faglige seminarer på KA, forår 2005. Belyser transformation af det danske landskab fysisk som holdningsmæssigt, samt hvordan phd-arbejdets egen proces håndterer den....

  4. 基于可变频变压器的双馈风电系统低电压穿越控制%Low Voltage Ride Through Control of Doubly-Fed Induction Generator Based on Variable Frequency Transformer

    Institute of Scientific and Technical Information of China (English)

    方泽钦; 杨俊华; 陈思哲; 吴捷

    2016-01-01

    在电网电压发生跌落故障期间,基于Crowbar电路的双馈风力发电( DFIG)系统需吸收大量无功功率。为提高DFIG风电机组并网运行稳定性,提出增设可变频变压器( VFT)新方案。 VFT由双馈电机、直流电机及驱动器构成。 Crowbar电路动作后,通过控制低电压穿越( LVRT)期间的VFT转速来抑制系统转差率,减小系统无功功率吸收量,基于 MATLAB/Simulink 平台,进行了暂态仿真研究。结果表明,故障期间在Crowbar电路起动后,所提控制策略能避免系统从电网中吸收过量无功功率,避免发电机转差率越限,有助于电网电压的恢复,DFIG风电机组的LVRT性能提高。%The vast grid reactive power would be absorbed by the crowbar-based doubly-fed induction generator ( DFIG) wind turbine when grid voltage dip fault. To improve the stability of power grid with DFIG wind turbines, a new low voltage ride-through ( LVRT ) control strategy was proposed for DFIG wind turbine by adding a variable frequency transformer ( VFT) between DFIG and grid. The VFT was composed of a doubly-fed induction machine, a DC motor and its drive system. During the crowbar circuit active, the slip of DFIG could be restrained with controlling the rotary speed of VFT during LVRT to reduce the amount of reactive power consumption. With MATLAB/Simulink simulation platform, the dynamic process of DFIG system was simulated during the voltage sag. The simulation results showed that the amount of reactive power absorbed by DFIG system from grid could be decreased and the slip ratio of DFIG could be limit below the critical value with the proposed control strategy during voltage sag, which contributes to the recovery of the grid voltage and improves the LVRT performance of DFIG wind turbine.

  5. High-frequency magnetic components

    CERN Document Server

    Kazimierczuk, Marian K

    2009-01-01

    If you are looking for a complete study of the fundamental concepts in magnetic theory, read this book. No other textbook covers magnetic components of inductors and transformers for high-frequency applications in detail. This unique text examines design techniques of the major types of inductors and transformers used for a wide variety of high-frequency applications including switching-mode power supplies (SMPS) and resonant circuits. It describes skin effect and proximity effect in detail to provide you with a sound understanding of high-frequency phenomena. As well as this, you will disco

  6. Técnicas de diagnóstico en transformadores a partir de su respuesta en el dominio de la frecuencia. Estado mundial del arte. Parte II; Techniques of Diagnostic in Transformers from their Answer in Frequency Domain. World State of the Art. Part II

    Directory of Open Access Journals (Sweden)

    Orestes Hernández Areu

    2011-02-01

    Full Text Available Entre los métodos para el diagnóstico de transformadores de potencia se encuentran los métodos de detecciónde averías a través del llamado análisis de la respuesta en la frecuencia (FRA. En un artículo anterior, sepresentó la primera parte del estudio que se ha realizado del estado mundial del arte sobre las técnicas dediagnóstico de transformadores a partir de su respuesta en el dominio de la frecuencia y empleando latransformada rápida de Fourier (FFT. Esta segunda parte, trata específicamente, sobre los métodos dediagnóstico de transformadores mediante el análisis de la respuesta a un barrido de frecuencia (SFRA, sin lautilización de  la transformada rápida de Fourier (FFT.  In the methods for the diagnosis of power transformers there are the failure detection methods called frequencyresponse analysis (FRA. In a previous article, the first part of a study that has been carried out about theworld art state on the techniques of diagnostic in transformers from its response in the frequency domain andusing the fast Fourier transformed (FFT, was presented.This second part, tries specifically about the methodsof diagnostic of transformers by means of the sweeping frequency response analysis (SFRA, without usingthe fast Fourier tansformed (FFT.

  7. Damping Estimation by Frequency Domain Decomposition

    DEFF Research Database (Denmark)

    Brincker, Rune; Ventura, C. E.; Andersen, P.

    2001-01-01

    frequencies can be accurately estimated without being limited by the frequency resolution of the discrete Fourier transform. It is explained how the spectral density matrix is decomposed into a set of single degree of freedom systems, and how the individual SDOF auto spectral density functions are transformed...

  8. Power System Transients Analysis by Wavelet Transforms

    Institute of Scientific and Technical Information of China (English)

    陈维荣; 宋永华; 赵蔚

    2002-01-01

    In contrast to Fourier transform, wavelet transform is especially suitable for transient analysis because of its time-frequency characteristics with automatically-adjusted window lengths. Research shows that wavelet transform is one of the most powerful tools for power system transient analysis. The basic ideas of wavelet transform are presented in the paper together with several power system applications. It is clear that wavelet transform has some clear advantages over other transforms in detecting, analyzing, and identifying various types of power system transients.

  9. Piezoelectric Transformers: An Historical Review

    Directory of Open Access Journals (Sweden)

    Alfredo Vazquez Carazo

    2016-04-01

    Full Text Available Piezoelectric transformers (PTs are solid-state devices that transform electrical energy into electrical energy by means of a mechanical vibration. These devices are manufactured using piezoelectric materials that are driven at resonance. With appropriate design and circuitry, it is possible to step up and step down the voltages between the input and output sections of the piezoelectric transformer, without making use of magnetic materials and obtaining excellent conversion efficiencies. The initial concept of a piezoelectric ceramic transformer was proposed by Charles A. Rosen in 1954. Since then, the evolution of piezoelectric transformers through history has been linked to the relevant work of some excellent researchers as well as to the evolution in materials, manufacturing processes, and driving circuit techniques. This paper summarizes the historical evolution of the technology.

  10. Joint Time-Frequency And Wavelet Analysis - An Introduction

    OpenAIRE

    Majkowski Andrzej; Kołodziej Marcin; Rak Remigiusz J.

    2014-01-01

    A traditional frequency analysis is not appropriate for observation of properties of non-stationary signals. This stems from the fact that the time resolution is not defined in the Fourier spectrum. Thus, there is a need for methods implementing joint time-frequency analysis (t/f) algorithms. Practical aspects of some representative methods of time-frequency analysis, including Short Time Fourier Transform, Gabor Transform, Wigner-Ville Transform and Cone-Shaped Transform are described in thi...

  11. Identity transformation

    DEFF Research Database (Denmark)

    Neergaard, Helle; Robinson, Sarah; Jones, Sally

    This paper develops the concept of ‘pedagogical nudging’ and examines four interventions in an entrepreneurship classroom and the potential it has for student identity transformation. Pedagogical nudging is positioned as a tool, which in the hands of a reflective, professional, with an understand......This paper develops the concept of ‘pedagogical nudging’ and examines four interventions in an entrepreneurship classroom and the potential it has for student identity transformation. Pedagogical nudging is positioned as a tool, which in the hands of a reflective, professional......, as well as the resources they have when they come to the classroom. It also incorporates perspectives from (ii) transformational learning and explores the concept of (iii) nudging from a pedagogical viewpoint, proposing it as an important tool in entrepreneurship education. The study incorporates......) assists students in straddling the divide between identities, the emotions and tensions this elicits, and (iv) transform student understanding. We extend nudging theory into a new territory. Pedagogical nudging techniques may be able to unlock doors and bring our students beyond the unacknowledged...

  12. Sustainable transformation

    DEFF Research Database (Denmark)

    Andersen, Nicolai Bo

    , that it can be adapted to changing functional needs, and that it has an architectural and cultural value. A specific proposal for a transformation that enhances the architectural qualities and building heritage values of an existing building forms the empirical material, which is discussed using different...

  13. ADE Transform

    CERN Document Server

    Donagi, Ron

    2015-01-01

    There is a beautiful correspondence between configurations of lines on a rational surface and tautological bundles over that surface. We extend this correspondence to families, by means of a generalized Fourier-Mukai transform that relates spectral data to bundles over a rational surface fibration.

  14. Transformer core

    NARCIS (Netherlands)

    Mehendale, A.; Hagedoorn, Wouter; Lötters, Joost Conrad

    2010-01-01

    A transformer core includes a stack of a plurality of planar core plates of a magnetically permeable material, which plates each consist of a first and a second sub-part that together enclose at least one opening. The sub-parts can be fitted together via contact faces that are located on either side

  15. Transformer core

    NARCIS (Netherlands)

    Mehendale, A.; Hagedoorn, Wouter; Lötters, Joost Conrad

    2008-01-01

    A transformer core includes a stack of a plurality of planar core plates of a magnetically permeable material, which plates each consist of a first and a second sub-part that together enclose at least one opening. The sub-parts can be fitted together via contact faces that are located on either side

  16. Transformational change

    NARCIS (Netherlands)

    Termeer, Katrien; Dewulf, Art; Biesbroek, Robbert

    2016-01-01

    Although transformational change is a rather new topic in climate change adaptation literature, it has been studied in organisational theory for over 30 years. This paper argues that governance scholars can learn much from organisation theory, more specifically regarding the conceptualisation of

  17. 广义S变换时频谱SVD降噪的滚动轴承故障冲击特征提取方法%Rolling Bearing Default Impact Feature Extracting Method Based on Generalized S Transform Time-Frequency Spectrum Denoised by SVD

    Institute of Scientific and Technical Information of China (English)

    朱怡; 蒋思源

    2016-01-01

    Based on the characteristic that the feature extraction of rolling bearing's weak fault is very hard under strong background noise,a new impact feature extracting method based on generalized S transform time-frequency spectrum denoised by SVD is proposed.Generalized S transform time-frequency resolution is high,the frequency spectrum en-ergy concentrated and suitable for processing and analyzing non-stationary characteristics of impact signal.The Hankel matrix is composed of generalized S transform spectrum coefficient.Singular values difference spectrum peak of the last peak point corresponding singular value is set as zero threshold.In the last,the time domain feature signal is got from the denoised data matrix of generalized S after inverse transformation.The simulation results show that the method based on generalized S transform time-frequency spectrum denoised by SVD can effectively extract the periodic impact characteristic in the low SNR signals.Finally this method is applied to impact rolling bearing fault feature extraction successfully,effectively extracting the characteristic frequency.%针对强背景噪声下滚动轴承故障冲击特征难以提取的特点,提出了基于广义S变换时频谱SVD降噪的滚动轴承故障冲击特征提取方法。利用广义S变换时频分辨率高,时频谱能量集中,适合处理与分析非平稳冲击信号的特点,将广义S变换时频谱系数矩阵作为SVD的Hankel矩阵,以奇异值差分谱峰值群最后一个峰值点对应的奇异值作为置零阈值,最后对降噪后的数据矩阵进行广义S逆变换得到时域冲击特征信号。仿真及实际研究表明,该方法能够有效地提取出低信噪比信号中的周期性冲击特征,并能够有效地提取轴承故障振动信号中的冲击特征频率。

  18. κ-deformed Fourier transform

    Science.gov (United States)

    Scarfone, A. M.

    2017-08-01

    We present a new formulation of Fourier transform in the picture of the κ-algebra derived in the framework of the κ-generalized statistical mechanics. The κ-Fourier transform is obtained from a κ-Fourier series recently introduced by Scarfone (2013). The kernel of this transform, that reduces to the usual exponential phase in the κ → 0 limit, is composed by a κ-deformed phase and a damping factor that gives a wavelet-like behaviour. We show that the κ-Fourier transform is isomorph to the standard Fourier transform through a changing of time and frequency variables. Nevertheless, the new formalism is useful to study, according to Fourier analysis, those functions defined in the realm of the κ-algebra. As a relevant application, we discuss the central limit theorem for the κ-sum of n-iterate statistically independent random variables.

  19. Frequency comb swept lasers.

    Science.gov (United States)

    Tsai, Tsung-Han; Zhou, Chao; Adler, Desmond C; Fujimoto, James G

    2009-11-09

    We demonstrate a frequency comb (FC) swept laser and a frequency comb Fourier domain mode locked (FC-FDML) laser for applications in optical coherence tomography (OCT). The fiber-based FC swept lasers operate at a sweep rate of 1kHz and 120kHz, respectively over a 135nm tuning range centered at 1310nm with average output powers of 50mW. A 25GHz free spectral range frequency comb filter in the swept lasers causes the lasers to generate a series of well defined frequency steps. The narrow bandwidth (0.015nm) of the frequency comb filter enables a approximately -1.2dB sensitivity roll off over approximately 3mm range, compared to conventional swept source and FDML lasers which have -10dB and -5dB roll offs, respectively. Measurements at very long ranges are possible with minimal sensitivity loss, however reflections from outside the principal measurement range of 0-3mm appear aliased back into the principal range. In addition, the frequency comb output from the lasers are equally spaced in frequency (linear in k-space). The filtered laser output can be used to self-clock the OCT interference signal sampling, enabling direct fast Fourier transformation of the fringe signals, without the need for fringe recalibration procedures. The design and operation principles of FC swept lasers are discussed and designs for short cavity lasers for OCT and interferometric measurement applications are proposed.

  20. Transforming Graph Representations for Statistical Relational Learning

    CERN Document Server

    Rossi, Ryan A; Aha, David W; Neville, Jennifer

    2012-01-01

    Relational data representations have become an increasingly important topic due to the recent proliferation of network datasets (e.g., social, biological, information networks) and a corresponding increase in the application of statistical relational learning (SRL) algorithms to these domains. In this article, we examine a range of representation issues for graph-based relational data. Since the choice of relational data representation for the nodes, links, and features can dramatically affect the capabilities of SRL algorithms, we survey approaches and opportunities for relational representation transformation designed to improve the performance of these algorithms. This leads us to introduce an intuitive taxonomy for data representation transformations in relational domains that incorporates link transformation and node transformation as symmetric representation tasks. In particular, the transformation tasks for both nodes and links include (i) predicting their existence, (ii) predicting their label or type...

  1. Quantifying and resolving multiple vector transformants in S. cerevisiae plasmid libraries

    Directory of Open Access Journals (Sweden)

    Gray Elizabeth C

    2009-11-01

    Full Text Available Abstract Background In addition to providing the molecular machinery for transcription and translation, recombinant microbial expression hosts maintain the critical genotype-phenotype link that is essential for high throughput screening and recovery of proteins encoded by plasmid libraries. It is known that Escherichia coli cells can be simultaneously transformed with multiple unique plasmids and thusly complicate recombinant library screening experiments. As a result of their potential to yield misleading results, bacterial multiple vector transformants have been thoroughly characterized in previous model studies. In contrast to bacterial systems, there is little quantitative information available regarding multiple vector transformants in yeast. Saccharomyces cerevisiae is the most widely used eukaryotic platform for cell surface display, combinatorial protein engineering, and other recombinant library screens. In order to characterize the extent and nature of multiple vector transformants in this important host, plasmid-born gene libraries constructed by yeast homologous recombination were analyzed by DNA sequencing. Results It was found that up to 90% of clones in yeast homologous recombination libraries may be multiple vector transformants, that on average these clones bear four or more unique mutant genes, and that these multiple vector cells persist as a significant proportion of library populations for greater than 24 hours during liquid outgrowth. Both vector concentration and vector to insert ratio influenced the library proportion of multiple vector transformants, but their population frequency was independent of transformation efficiency. Interestingly, the average number of plasmids born by multiple vector transformants did not vary with their library population proportion. Conclusion These results highlight the potential for multiple vector transformants to dominate yeast libraries constructed by homologous recombination. The

  2. Discrete transforms

    CERN Document Server

    Firth, Jean M

    1992-01-01

    The analysis of signals and systems using transform methods is a very important aspect of the examination of processes and problems in an increasingly wide range of applications. Whereas the initial impetus in the development of methods appropriate for handling discrete sets of data occurred mainly in an electrical engineering context (for example in the design of digital filters), the same techniques are in use in such disciplines as cardiology, optics, speech analysis and management, as well as in other branches of science and engineering. This text is aimed at a readership whose mathematical background includes some acquaintance with complex numbers, linear differen­ tial equations, matrix algebra, and series. Specifically, a familiarity with Fourier series (in trigonometric and exponential forms) is assumed, and an exposure to the concept of a continuous integral transform is desirable. Such a background can be expected, for example, on completion of the first year of a science or engineering degree cour...

  3. Transformation optics using graphene.

    Science.gov (United States)

    Vakil, Ashkan; Engheta, Nader

    2011-06-10

    Metamaterials and transformation optics play substantial roles in various branches of optical science and engineering by providing schemes to tailor electromagnetic fields into desired spatial patterns. We report a theoretical study showing that by designing and manipulating spatially inhomogeneous, nonuniform conductivity patterns across a flake of graphene, one can have this material as a one-atom-thick platform for infrared metamaterials and transformation optical devices. Varying the graphene chemical potential by using static electric field yields a way to tune the graphene conductivity in the terahertz and infrared frequencies. Such degree of freedom provides the prospect of having different "patches" with different conductivities on a single flake of graphene. Numerous photonic functions and metamaterial concepts can be expected to follow from such a platform.

  4. XML Transformations

    Directory of Open Access Journals (Sweden)

    Felician ALECU

    2012-04-01

    Full Text Available XSLT style sheets are designed to transform the XML documents into something else. The two most popular parsers of the moment are the Document Object Model (DOM and the Simple API for XML (SAX. DOM is an official recommendation of the W3C (available at http://www.w3.org/TR/REC-DOM-Level-1, while SAX is a de facto standard. A good parser should be fast, space efficient, rich in functionality and easy to use.

  5. Transformative Agency

    DEFF Research Database (Denmark)

    Majgaard, Klaus

    The purpose of this paper is to enhance the conceptual understanding of the mediatory relationship between paradoxes on an organizational and an individual level. It presents a concept of agency that comprises and mediates between a structural and individual pole. The constitution of this agency ...... is achieved through narrative activity that oscillates between the poles and transforms paradoxes through the configuration of plots and metaphors. Empirical cases are introduced in order to illustrate the implications of this understanding....

  6. RF transformer

    Science.gov (United States)

    Smith, James L.; Helenberg, Harold W.; Kilsdonk, Dennis J.

    1979-01-01

    There is provided an improved RF transformer having a single-turn secondary of cylindrical shape and a coiled encapsulated primary contained within the secondary. The coil is tapered so that the narrowest separation between the primary and the secondary is at one end of the coil. The encapsulated primary is removable from the secondary so that a variety of different capacity primaries can be utilized with one secondary.

  7. Subspaces of FMmlet transform

    Institute of Scientific and Technical Information of China (English)

    邹红星; 戴琼海; 赵克; 陈桂明; 李衍达

    2002-01-01

    The subspaces of FMmlet transform are investigated.It is shown that some of the existing transforms like the Fourier transform,short-time Fourier transform,Gabor transform,wavelet transform,chirplet transform,the mean of signal,and the FM-1let transform,and the butterfly subspace are all special cases of FMmlet transform.Therefore the FMmlet transform is more flexible for delineating both the linear and nonlinear time-varying structures of a signal.

  8. Transatlantic link

    Science.gov (United States)

    (left) European Geophysical Society (EGS) President Rolf Meissner at AGU Headquarters with (center) Executive Director Fred Spilhaus and (right) Foreign Secretary Juan Roederer. Meissner attended the meeting of AGU's Committee on International Participation (CIP) on February 26, 1988. At that meeting, specific ways of fostering close links between AGU and EGS were discussed.A few weeks later, Roederer and AGU staff, working with EGS Secretary-General Arne Richter at the EGS meeting in Bologna, Italy, March 21-25, planned details of the establishment of an AGU office in Europe. The Copernicus Gesellschaft, a new entity located on the premises of the Max Planck Institute for Aeronomy in Lindau, Federal Republic of Germany, will provide the administrative staff and handle logistics.

  9. Frequency standards

    CERN Document Server

    Riehle, Fritz

    2006-01-01

    Of all measurement units, frequency is the one that may be determined with the highest degree of accuracy. It equally allows precise measurements of other physical and technical quantities, whenever they can be measured in terms of frequency.This volume covers the central methods and techniques relevant for frequency standards developed in physics, electronics, quantum electronics, and statistics. After a review of the basic principles, the book looks at the realisation of commonly used components. It then continues with the description and characterisation of important frequency standards

  10. Relations of FMmlet Transform to Some Integral Transforms

    Institute of Scientific and Technical Information of China (English)

    ZOUHongxing; DAIQionghai; WANGDianjun; LIYanda

    2004-01-01

    In this paper, we explore the relationships between FMmlet transform and some of the existing integral transforms, namely, the chirplet transform, dispersion transform, wavelet transform, chirp-Fourier transform, Short-time fourier transform (STFT), Gabor transform, Fourier transform, cosine transform, sine transform,Hartley transform, Laplace transform, z-transform, Mellintransform, Hilbert transform, autocorrelation function,cross-correlation function, energy, and the mean value.It is shown that all of these transforms are subspaces of FMmlet transform with specific parameters.

  11. Transformational Leadership and Job-related Learning

    OpenAIRE

    Loon, Mark; Lim, Y. M.

    2007-01-01

    Various empirical studies have examined transformational leadership on the effects of followers and organisations. Transformational leadership has been related to individual attitudes and behaviors such as satisfaction with leaders, organisational citizenship behavior, organisational commitment, motivation, trust in leader, creativity, performance, employee involvement, and empowerment. It has also been linked to such organisational outcomes as innovation, change, productivity, ethical climat...

  12. The simulation study of three typical time frequency analysis methods

    Directory of Open Access Journals (Sweden)

    Li Yifeng

    2017-01-01

    Full Text Available The principals and characteristics of three typical time frequency analysis methods that Short Time Furious transformation, wavelet transformation and Hilbert-Huang transformation are introduced, and the mathematical definition, characteristics and application ranges of these analysis methods and so on are pointed out, then their time-frequency local performance is made analysis and comparison through computer programming and simulation.

  13. Relation between Type-II Discrete Sine Transform and Type -I Discrete Hartley Transform

    Directory of Open Access Journals (Sweden)

    M.Narayan Murty

    2017-06-01

    Full Text Available In this paper, a relation for finding type-II discrete sine transform (DST from type-I discrete Hartley transform (DHT has been derived. The transform length N is taken as even. Using this relation, the (N - 1 output components of DST can be realized from DHT. The DHT is one of the transforms used for converting data in time domain into frequency domain using only real values.

  14. TRANSFORMATION OF BACILLUS LICHENIFORMIS1

    Science.gov (United States)

    Gwinn, Darrel D.; Thorne, Curtis B.

    1964-01-01

    Gwinn, Darrel D. (Oregon State University, Corvallis), and Curtis B. Thorne. Transformation of Bacillus licheniformis. J. Bacteriol. 87:519–526. 1964.—When a series of 28 auxotrophic mutants of Bacillus licheniformis were screened for transformation, only three of them, M28 (glycine−), M30 (uncharacterized), and M33 (purine−), produced a detectable number of transformants. The screening method consisted of spreading auxotrophic cells and deoxyribonucleic acid (DNA) from the prototrophic strain 9945A on minimal agar plates and observing the plates for development of prototrophic colonies. M28 transformed at a higher frequency than did the two other mutants, and it was studied in greater detail. Although up to 20% of the recipient cells spread on the plates in the presence of DNA gave rise to prototrophic colonies over a period of 72 hr, only about 10−3% of the cells produced transformants when they were incubated with DNA in liquid suspension for 1 hr. The most competent cultures of many tested were those grown on a shaker for 22 hr in a medium composed of nutrient broth, salts, and glycerol. When mutations resulting in requirements for histidine, leucine, serine, and trytophan were introduced singly into the glycine mutant, transformants for the leucine, serine, and histidine markers could be obtained at will, but transformants for the tryptophan marker were not detected even though all four of the double mutants could be transformed to glycine independence. PMID:14127566

  15. Adaptive Fourier Decomposition Based Time-Frequency Analysis

    Institute of Scientific and Technical Information of China (English)

    Li-Ming Zhang

    2014-01-01

    The attempt to represent a signal simultaneously in time and frequency domains is full of challenges. The recently proposed adaptive Fourier decomposition (AFD) offers a practical approach to solve this problem. This paper presents the principles of the AFD based time-frequency analysis in three aspects: instantaneous frequency analysis, frequency spectrum analysis, and the spectrogram analysis. An experiment is conducted and compared with the Fourier transform in convergence rate and short-time Fourier transform in time-frequency distribution. The proposed approach performs better than both the Fourier transform and short-time Fourier transform.

  16. Frequency synthesiser

    NARCIS (Netherlands)

    Drago, Salvatore; Sebastiano, Fabio; Leenaerts, Dominicus Martinus Wilhelmus; Breems, Lucien Johannes; Nauta, Bram

    2016-01-01

    A low power frequency synthesiser circuit (30) for a radio transceiver, the synthesiser circuit comprising: a digital controlled oscillator configured to generate an output signal having a frequency controlled by an input digital control word (DCW); a feedback loop connected between an output and an

  17. Fast Link Adaptation for MIMO-OFDM

    DEFF Research Database (Denmark)

    Jensen, Tobias Lindstrøm; Kant, Shashi; Wehinger, Joachim;

    2010-01-01

    We investigate link-quality metrics (LQMs) based on raw bit-error-rate, effective signal-to-interference-plus-noise ratio, and mutual information (MI) for the purpose of fast link adaptation (LA) in communication systems employing orthogonal frequency-division multiplexing and multiple-input–mult......We investigate link-quality metrics (LQMs) based on raw bit-error-rate, effective signal-to-interference-plus-noise ratio, and mutual information (MI) for the purpose of fast link adaptation (LA) in communication systems employing orthogonal frequency-division multiplexing and multiple...

  18. Analysis of nonlinear behavior of loudspeakers using the instantaneous frequency

    DEFF Research Database (Denmark)

    Huang, Hai; Jacobsen, Finn

    2003-01-01

    It is well know that the weakest link in a sound reproduction chain is the loudspeaker. The most significant effect on the sound quality is nonlinear distortion of loudspeakers. Many methods are applied to analyze the nonlinear distortion of loudspeakers. Almost all of the methods are based...... on the Fourier transform. In this work, a new method using the instantaneous frequency is introduced for describing and characterizing loudspeaker nonlinearities. First, numerical integration is applied to simulate the nonlinearities of loudspeakers caused by two nonlinear parameters, force factor and stiffness......, separately. Then, a practical loudspeaker is used in an experiment and its nonlinear characteristics are analyzed with the instantaneous frequency. The results provide a clear physical interpretation of the nonlinearities of loudspeakers and will be useful for understanding the nonlinear behavior...

  19. Hamlet's Transformation.

    Science.gov (United States)

    Usher, P. D.

    1997-12-01

    William Shakespeare's Hamlet has much evidence to suggest that the Bard was aware of the cosmological models of his time, specifically the geocentric bounded Ptolemaic and Tychonic models, and the infinite Diggesian. Moreover, Shakespeare describes how the Ptolemaic model is to be transformed to the Diggesian. Hamlet's "transformation" is the reason that Claudius, who personifies the Ptolemaic model, summons Rosencrantz and Guildenstern, who personify the Tychonic. Pantometria, written by Leonard Digges and his son Thomas in 1571, contains the first technical use of the word "transformation." At age thirty, Thomas Digges went on to propose his Perfit Description, as alluded to in Act Five where Hamlet's age is given as thirty. In Act Five as well, the words "bore" and "arms" refer to Thomas' vocation as muster-master and his scientific interest in ballistics. England's leading astronomer was also the father of the poet whose encomium introduced the First Folio of 1623. His oldest child Dudley became a member of the Virginia Company and facilitated the writing of The Tempest. Taken as a whole, such manifold connections to Thomas Digges support Hotson's contention that Shakespeare knew the Digges family. Rosencrantz and Guildenstern in Hamlet bear Danish names because they personify the Danish model, while the king's name is latinized like that of Claudius Ptolemaeus. The reason Shakespeare anglicized "Amleth" to "Hamlet" was because he saw a parallel between Book Three of Saxo Grammaticus and the eventual triumph of the Diggesian model. But Shakespeare eschewed Book Four, creating this particular ending from an infinity of other possibilities because it "suited his purpose," viz. to celebrate the concept of a boundless universe of stars like the Sun.

  20. Rotary Transformer

    Science.gov (United States)

    McLyman, Colonel Wm. T.

    1996-01-01

    None given. From first Par: Many spacecraft (S/C) and surface rovers require the transfer of signals and power across rotating interfaces. Science instruments, antennas and solar arrays are elements needing rotary power transfer for certain (S/C) configurations. Delivery of signal and power has mainly been done by using the simplest means, the slip ring approach. This approach, although simple, leaves debris generating noise over a period of time...The rotary transformer is a good alternative to slip rings for signal and power transfer.

  1. TRANSFORMER APPARATUS

    Science.gov (United States)

    Wolfgang, F.; Nicol, J.

    1962-11-01

    Transformer apparatus is designed for measuring the amount of a paramagnetic substance dissolved or suspended in a diamagnetic liquid. The apparatus consists of a cluster of tubes, some of which are closed and have sealed within the diamagnetic substance without any of the paramagnetic material. The remaining tubes are open to flow of the mix- ture. Primary and secondary conductors are wrapped around the tubes in such a way as to cancel noise components and also to produce a differential signal on the secondaries based upon variations of the content of the paramagnetic material. (AEC)

  2. Co-fired magnetoelectric transformer

    Science.gov (United States)

    Zhou, Yuan; Yan, Yongke; Priya, Shashank

    2014-06-01

    In this study, we demonstrate a co-fired magnetoelectric (ME) laminate consisting of piezoelectric/magnetostrictive/piezoelectric layers with unipoled piezoelectric transformer structure. The ME transformer was characterized by quantifying the voltage gain variation and resonance frequency shift as a function of applied DC magnetic field. We delineate the magnetic tunability feature by considering the magnetoelectric coupling and delta-E effect, where E represents the modulus of magnetic material. The ME response of the composite structure was found to be 473 mV/cm.Oe exhibiting DC field sensitivity of 100 nT under AC field of 1 Oe at 1 kHz. At a magnetic bias of 60 Oe, the transformer exhibited large frequency tunability of the order of 1.4 Hz/Oe. These results present significant advancement towards developing on-chip magnetic-field-tunable devices.

  3. A Transformer Class E Amplifier

    Directory of Open Access Journals (Sweden)

    Mikolajewski Miroslaw

    2014-12-01

    Full Text Available In a high-efficiency Class E ZVS resonant amplifier a matching and isolation transformer can replace some or even all inductive components of the amplifier thus simplifying the circuit and reducing its cost. In the paper a theoretical analysis, a design example and its experimental verification for a transformer Class E amplifier are presented. In the experimental amplifier with a transformer as the only inductive component in the circuit high efficiency ηMAX = 0.95 was achieved for supply voltage VI = 36 V, maximum output power POMAX = 100 W and the switching frequency f = 300 kHz. Measured parameters and waveforms showed a good agreement with theoretical predictions. Moreover, the relative bandwidth of the switching frequency was only 19% to obtain output power control from 4.8 W to POMAX with efficiency not less than 0.9 in the regulation range.

  4. Fourier transform based dynamic error modeling method for ultra-precision machine tool

    Science.gov (United States)

    Chen, Guoda; Liang, Yingchun; Ehmann, Kornel F.; Sun, Yazhou; Bai, Qingshun

    2014-08-01

    In some industrial fields, the workpiece surface need to meet not only the demand of surface roughness, but the strict requirement of multi-scale frequency domain errors. Ultra-precision machine tool is the most important carrier for the ultra-precision machining of the parts, whose errors is the key factor to influence the multi-scale frequency domain errors of the machined surface. The volumetric error modeling is the important bridge to link the relationship between the machine error and machined surface error. However, the available error modeling method from the previous research is hard to use to analyze the relationship between the dynamic errors of the machine motion components and multi-scale frequency domain errors of the machined surface, which plays the important reference role in the design and accuracy improvement of the ultra-precision machine tool. In this paper, a fourier transform based dynamic error modeling method is presented, which is also on the theoretical basis of rigid body kinematics and homogeneous transformation matrix. A case study is carried out, which shows the proposed method can successfully realize the identical and regular numerical description of the machine dynamic errors and the volumetric errors. The proposed method has strong potential for the prediction of the frequency domain errors on the machined surface, extracting of the information of multi-scale frequency domain errors, and analysis of the relationship between the machine motion components and frequency domain errors of the machined surface.

  5. Dancing links

    CERN Document Server

    Knuth, Donald E

    2009-01-01

    The author presents two tricks to accelerate depth-first search algorithms for a class of combinatorial puzzle problems, such as tiling a tray by a fixed set of polyominoes. The first trick is to implement each assumption of the search with reversible local operations on doubly linked lists. By this trick, every step of the search affects the data incrementally. The second trick is to add a ghost square that represents the identity of each polyomino. Thus puts the rule that each polyomino be used once on the same footing as the rule that each square be covered once. The coding simplifies to a more abstract form which is equivalent to 0-1 integer programming. More significantly for the total computation time, the search can naturally switch between placing a fixed polyomino or covering a fixed square at different stages, according to a combined heuristic. Finally the author reports excellent performance for his algorithm for some familiar puzzles. These include tiling a hexagon by 19 hexiamonds and the N queen...

  6. Transformational leadership.

    Science.gov (United States)

    Marlow, D L

    1996-01-01

    In these uncertain times in the healthcare industry, administrators are asked to do more with less time and resources. Because of the extended roles they are playing in today's organizations, radiology administrators are looked upon as agents of change. What leadership skills do they need in this turbulent and uncertain healthcare environment? What are the trait's of tomorrow's leaders? The transformational leader is the one who will guide us through this changing healthcare environment. Several behavioral patterns emerge as important traits for tomorrow's leaders to have-individual consideration, intellectual stimulation and charisma. Tomorrow's leader must view each person as an individual, showing genuine concern and belief in each person's ability to perform. Transformational leaders stimulate others by encouraging them to be curious and try new ideas. The final characteristic, charisma, is the ability to inspire others. Luckily, leaders are made, not born: today's leaders can learn to be responsive, to draw out new ideas from employees, and to communicate self-esteem, energy and enthusiasm.

  7. High spectral purity Kerr frequency comb radio frequency photonic oscillator.

    Science.gov (United States)

    Liang, W; Eliyahu, D; Ilchenko, V S; Savchenkov, A A; Matsko, A B; Seidel, D; Maleki, L

    2015-08-11

    Femtosecond laser-based generation of radio frequency signals has produced astonishing improvements in achievable spectral purity, one of the basic features characterizing the performance of an radio frequency oscillator. Kerr frequency combs hold promise for transforming these lab-scale oscillators to chip-scale level. In this work we demonstrate a miniature 10 GHz radio frequency photonic oscillator characterized with phase noise better than -60 dBc Hz(-1) at 10 Hz, -90 dBc Hz(-1) at 100 Hz and -170 dBc Hz(-1) at 10 MHz. The frequency stability of this device, as represented by Allan deviation measurements, is at the level of 10(-10) at 1-100 s integration time-orders of magnitude better than existing radio frequency photonic devices of similar size, weight and power consumption.

  8. Frequency conversion technology transformation plan design on The coal warehouse belt system%煤矿上仓皮带系统变频技术改造方案设计

    Institute of Scientific and Technical Information of China (English)

    田伟

    2012-01-01

      Frequency control technology is an ideal high-efficiency and high-performance speed control means,which through the change of the motor power supply frequency, so as to realize the speed adjustment.%  变频调速技术就是这样通过改变电动机的供电电源频率,从而实现速度调节的,是一种理想的高效率、高性能的调速手段。

  9. Subband/transform functions for image processing

    Science.gov (United States)

    Glover, Daniel

    1993-01-01

    Functions for image data processing written for use with the MATLAB(TM) software package are presented. These functions provide the capability to transform image data with block transformations (such as the Walsh Hadamard) and to produce spatial frequency subbands of the transformed data. Block transforms are equivalent to simple subband systems. The transform coefficients are reordered using a simple permutation to give subbands. The low frequency subband is a low resolution version of the original image, while the higher frequency subbands contain edge information. The transform functions can be cascaded to provide further decomposition into more subbands. If the cascade is applied to all four of the first stage subbands (in the case of a four band decomposition), then a uniform structure of sixteen bands is obtained. If the cascade is applied only to the low frequency subband, an octave structure of seven bands results. Functions for the inverse transforms are also given. These functions can be used for image data compression systems. The transforms do not in themselves produce data compression, but prepare the data for quantization and compression. Sample quantization functions for subbands are also given. A typical compression approach is to subband the image data, quantize it, then use statistical coding (e.g., run-length coding followed by Huffman coding) for compression. Contour plots of image data and subbanded data are shown.

  10. The Link Prediction Problem in Bipartite Networks

    CERN Document Server

    Kunegis, Jérôme; Albayrak, Sahin

    2010-01-01

    We define and study the link prediction problem in bipartite networks, specializing general link prediction algorithms to the bipartite case. In a graph, a link prediction function of two vertices denotes the similarity or proximity of the vertices. Common link prediction functions for general graphs are defined using paths of length two between two nodes. Since in a bipartite graph adjacency vertices can only be connected by paths of odd lengths, these functions do not apply to bipartite graphs. Instead, a certain class of graph kernels (spectral transformation kernels) can be generalized to bipartite graphs when the positive-semidefinite kernel constraint is relaxed. This generalization is realized by the odd component of the underlying spectral transformation. This construction leads to several new link prediction pseudokernels such as the matrix hyperbolic sine, which we examine for rating graphs, authorship graphs, folksonomies, document--feature networks and other types of bipartite networks.

  11. Tackling the Limits of Optical Fiber Links

    CERN Document Server

    Stefani, Fabio; Bercy, Anthony; Lee, Won-Kyu; Chardonnet, Christian; Santarelli, Giorgio; Pottie, Paul-Eric; Amy-Klein, Anne

    2014-01-01

    We theoretically and experimentally investigate relevant noise processes arising in optical fiber links, which fundamentally limit their relative stability. We derive the unsuppressed delay noise for three configurations of optical links: two-way method, Sagnac interferometry, and actively compensated link, respectively designed for frequency comparison, rotation sensing, and frequency transfer. We also consider an alternative two-way setup allowing real-time frequency comparison and demonstrate its effectiveness on a proof-of-principle experiment with a 25-km fiber spool. For these three configurations, we analyze the noise arising from uncommon fiber paths in the interferometric ensemble and design optimized interferometers. We demonstrate interferometers with very low temperature sensitivity of respectively -2.2, -0.03 and 1 fs/K. We use one of these optimized interferometers on a long haul compensated fiber link of 540km. We obtain a relative frequency stability of 3E-20 after 10,000 s of integration time...

  12. A Low-Frequency Tone Sweep Method for in-Service Fault Location in Sub-Carrier Multiplexed Optical Fiber Networks

    CERN Document Server

    Amaral, Gustavo C; Baldivieso, Andrea; Garcia, Joaquim Dias; Leibel, Renata G; Herrera, Luis E Y; Urban, Patryk J; von der Weid, Jean Pierre

    2016-01-01

    We demonstrate an optical fiber fault location method based on the frequency response of the modulated fiber optical backscattered signal in a steady state low-frequency step regime. Careful calibration and measurement allows for the reconstruction of the fiber transfer function, which, associated to its mathematical model, is capable of extracting the fiber characteristics. The technique is capable of identifying non-reflective fault events in an optical fiber link and is perfectly compatible with previous methods that focus on the reflective events. The fact that the recuperation of the complex signal is performed in the frequency domain and not via a Fourier Transform enables the measurements to overcome the spatial resolution limitation of Fourier Transform incoherent-OFDR measurements even with frequency sweep ranges down to 100-100000 Hz. This result is backed up by a less than 10 meters difference in fault location when compared to standard OTDR measurements.

  13. Radio frequency identification-enabled capabilities in a healthcare context: An exploratory study.

    Science.gov (United States)

    Hornyak, Rob; Lewis, Mark; Sankaranarayan, Balaji

    2016-09-01

    Increasingly, the adoption and use of radio frequency identification systems in hospital settings is gaining prominence. However, despite the transformative impact that radio frequency identification has in healthcare settings, few studies have examined how and why this change may occur. The purpose of this study is to systematically understand how radio frequency identification can transform work practices in an operational process that directly impacts cost and operational efficiency and indirectly contributes to impacting patient safety and quality of care. We leverage an interdisciplinary framework to explore the contextual characteristics that shape the assimilation of radio frequency identification in healthcare settings. By linking the use of radio frequency identification with specific contextual dimensions in healthcare settings, we provide a data-driven account of how and why radio frequency identification can be useful in inventory management in this setting. In doing so, we also contribute to recent work by information systems scholars who argue for a reconfiguration of conventional assumptions regarding the role of technology in contemporary organizations.

  14. Implementation of Switch Mode Power Supply with In-series Secondary Windings of High-frequency Transformers%高频变压器次级串联开关电源的实现

    Institute of Scientific and Technical Information of China (English)

    田书欣; 钟莉娟; 杨喜军; 雷淮刚

    2011-01-01

    Based on planar transformer, secondary soft-switching technology and CA 1524 controller, 12 V/220 V DC/DC converter is designed, which is made up of single-stage push-pull inversion-full bridge rectification with the efficiency of 90%.Scheme with insories secondary windings of transformers is proposed to achieve output power of 1 kW and efficiency of 90%.The whole efficiency curves on the basis of different input voltage and different output power are shown.The experimental results indicate that switch mode power supply for multistage series secondary windings of transformers with resonant soft-switching has good indexes, which is suitable for application in situation of low input voltage and large input current.%基于平面变压器、次级软开关技术和CA 1524控制器,设计了满载效率为90%的单级推挽逆变一全桥整流的12 V/220 V DC/DC变换器单元,以及次级绕组两级串联方案,实现了输出功率1 kW以上,满载效率90%.给出了实测波形和不同输入电压和不同输出功率条件下的整机效率曲线.实验结果表明,谐振软开关次级多级串联开关电源各项指标良好,适合输入端为低电压大电流应用场合.

  15. Sex-linked dominant

    Science.gov (United States)

    Inheritance - sex-linked dominant; Genetics - sex-linked dominant; X-linked dominant; Y-linked dominant ... can be either an autosomal chromosome or a sex chromosome. It also depends on whether the trait ...

  16. Query transformations and their role in Web searching by the members of the general public

    Directory of Open Access Journals (Sweden)

    Martin Whittle

    2006-01-01

    Full Text Available Introduction. This paper reports preliminary research in a primarily experimental study of how the general public search for information on the Web. The focus is on the query transformation patterns that characterise searching. Method. In this work, we have used transaction logs from the Excite search engine to develop methods for analysing query transformations that should aid the analysis of our ongoing experimental work. Our methods involve the use of similarity techniques to link queries with the most similar previous query in a train. The resulting query transformations are represented as a list of codes representing a whole search. Analysis. It is shown how query transformation sequences can be represented as graphical networks and some basic statistical results are shown. A correlation analysis is performed to examine the co-occurrence of Boolean and quotation mark changes with the syntactic changes. Results. A frequency analysis of the occurrence of query transformation codes is presented. The connectivity of graphs obtained from the query transformation is investigated and found to follow an exponential scaling law. The correlation analysis reveals a number of patterns that provide some interesting insights into Web searching by the general public. Conclusion. We have developed analytical methods based on query similarity that can be applied to our current experimental work with volunteer subjects. The results of these will form part of a database with the aim of developing an improved understanding of how the public search the Web.

  17. Optimal Operation of Distribution Electronic Power Transformer Using Linear Quadratic Regulator Method

    Directory of Open Access Journals (Sweden)

    Mohammad Hosein Rezaei

    2011-10-01

    Full Text Available Transformers perform many functions such as voltage transformation, isolation and noise decoupling. They are indispensable components in electric power distribution system. However, at low frequencies (50 Hz, they are one of the heaviest and the most expensive equipment in an electrical distribution system. Nowadays, electronic power transformers are used instead of conventional power transformers that do voltage transformation and power delivery in power system by power electronic converter. In this paper, the structure of distribution electronic power transformer (DEPT are analized and then paid attention on the design of a linear-quadratic-regulator (LQR with integral action to improve dynamic performance of DEPT with voltage unbalance, voltage sags, voltage harmonics and voltage flicker. The presentation control strategy is simulated by MATLAB/SIMULINK. In addition, the results that are in terms of dc-link reference voltage, input and output voltages clearly show that a better dynamic performance can be achieved by using the LQR method when compared to other techniques.

  18. Study on the Time-frequency Characteristics of Engine Noise Signal with Transient Workload Based on Continuous Wavelet Transform%基于连续小波变换的内燃机瞬态工况噪声信号时频特性研究

    Institute of Scientific and Technical Information of China (English)

    徐红梅; 陈传艳

    2011-01-01

    Taking a four-cylinder gasoline engine as example , the front-end noise signal was recorded in acceleration and subdivided into several segments with the same length. Afterwards, continuous wavelet transform was adopted to analyze the data segments in time-frequency domain. The energy distribution of noise signals and variance of their predominant frequency components with time or engine speed were subsequently investigated. The results demonstrate that the energy of noise signal is concentrated nearby the 2 - order harmonic frequency and the linearly modulated frequency band defined by the fundamental frequency. With the increase of engine speed, the amplitude or energy of signal nearby the linearly modulated frequency band increases accordingly. There are other frequency components with lower amplitude and energy that is distributed on the upper part of the linearly modulated frequency band. Additionally, as engine speed increases, more and more frequency components are included in the upper area , and the energy distribution also becomes more and more extensive.%以某四缸汽油机为研究对象,发动机加速过程中,对前端噪声信号进行测试,并对采集的噪声信号进行等长度分段预处理.采用连续小波变换方法分别对各数据段的噪声信号进行时频分析处理,分析噪声信号能量在时频域内的分布规律,以及其主要频率成分随转速或时间变化的特性.结果表明,发动机加速过程中,噪声信号能量主要集中在2阶主谐次和转动基频构成的线性调频带附近,而且随着转速的升高,调频带附近的信号幅值和能量也随之增大.在调频带上方也分布着一些频率成分,但是其幅值和能量相对较小,而且随着转速的升高,其频率成分越来越丰富,能量分布也越来越广泛.

  19. Hydrogen peroxide inhibits transforming growth factor-β1-induced cell cycle arrest by promoting Smad3 linker phosphorylation through activation of Akt-ERK1/2-linked signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jiyeon; Park, Seong Ji; Jo, Eun Ji [Department of Biochemistry, College of Natural Sciences, Kangwon National University, Chuncheon 200-701 (Korea, Republic of); Lee, Hui-Young [Department of Internal Medicine, Kangwon National University, Chuncheon 200-701 (Korea, Republic of); Hong, Suntaek [Laboratory of Cancer Cell Biology, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon 406-840 (Korea, Republic of); Kim, Seong-Jin [CHA Cancer Institute, CHA University of Medicine and Science, Seoul 135-081 (Korea, Republic of); Kim, Byung-Chul, E-mail: bckim@kangwon.ac.kr [Department of Biochemistry, College of Natural Sciences, Kangwon National University, Chuncheon 200-701 (Korea, Republic of)

    2013-06-14

    Highlights: •H{sub 2}O{sub 2} inhibits TGF-β1-induced cell cycle arrest. •H{sub 2}O{sub 2} induces Smad3 linker phosphorylation through Akt-ERK1/2 pathway. •H{sub 2}O{sub 2}-mediated suppression of TGF-β signal requires Smad3 linker phosphorylation. •This is a first report about interplay between H{sub 2}O{sub 2} and growth inhibition pathway. -- Abstract: Hydrogen peroxide (H{sub 2}O{sub 2}) functions as a second messenger in growth factor receptor-mediated intracellular signaling cascade and is tumorigenic by virtue of its ability to promote cell proliferation; however, the mechanisms underlying the growth stimulatory action of H{sub 2}O{sub 2} are less understood. Here we report an important mechanism for antagonistic effects of H{sub 2}O{sub 2} on growth inhibitory response to transforming growth factor-β1 (TGF-β1). In Mv1Lu and HepG2 cells, pretreatment of H{sub 2}O{sub 2} (0.05–0.2 mM) completely blocked TGF-β1-mediated induction of p15{sup INK4B} expression and increase of its promoter activity. Interestingly, H{sub 2}O{sub 2} selectively suppressed the transcriptional activation potential of Smad3, not Smad2, in the absence of effects on TGF-β1-induced phosphorylation of the COOH-tail SSXS motif of Smad3 and its nuclear translocation. Mechanism studies showed that H{sub 2}O{sub 2} increases the phosphorylation of Smad3 at the middle linker region in a concentration- and time-dependent manner and this effect is mediated by activation of extracellular signal-activated kinase 1/2 through Akt. Furthermore, expression of a mutant Smad3 in which linker phosphorylation sites were ablated significantly abrogated the inhibitory effects of H{sub 2}O{sub 2} on TGF-β1-induced increase of p15{sup INK4B}-Luc reporter activity and blockade of cell cycle progression from G1 to S phase. These findings for the first time define H{sub 2}O{sub 2} as a signaling molecule that modulate Smad3 linker phosphorylation and its transcriptional activity, thus providing

  20. IDENTIFICATION OF CRACKED ROTOR BY WAVELET TRANSFORM

    Institute of Scientific and Technical Information of China (English)

    邹剑; 陈进; 蒲亚鹏

    2002-01-01

    The dynamic equation of cracked rotor in rotational frame was modelled, the numerical simulation solutions of the cracked rotor and the uncracked rotor were obtained. By the wavelet transform, the time-frequency properties of the cracked rotor and the uncracked rotor were discussed, the difference of the time-frequency properties between the cracked rotor and the uncracked rotor was compared. A new detection algorithm using wavelet transform to identify crack was proposed. The experiments verify the availability and validity of the wavelet transform in identification of crack.

  1. Linking place and mind

    DEFF Research Database (Denmark)

    Jensen, Marie Møller

    2016-01-01

    This paper investigates the salience of vernacular Tyneside forms on the basis of theories of enregisterment and exemplar processing. On one level, exemplar theory provides a psycholinguistic account of how the link between social value and linguistic features is possible. Conversely, integrating...... the notion of social value into exemplar theory extends the value of this originally cognitive theory to social domains. It is suggested that the association of social value and particular local, linguistic forms may contribute to the salience of these forms among local speakers. The empirical work reported...... here takes the form of a questionnaire study, which aims to uncover Tyneside inhabitants' awareness of forms as well as their affiliation with the local community. Results showed differences in frequency perceptions between participants themselves and others which indicate that speakers can identify...

  2. The Dynamic Frequency Assignment Problem

    OpenAIRE

    Dupont, Audrey; Linhares, Andréa,; Artigues, Christian; Feillet, Dominique; Michelon, Philippe; Vasquez, Michel

    2008-01-01

    21 pages; International audience; In this paper, we consider a frequency assignment problem occurring in a military context. The main originality of the problem pertains to its dynamic dimension: new communications requiring frequency assignments need to be established throughout a deployment. The problem decomposes in three phases: assignment of an initial kernel of communications, dynamic assignment of new communication links and reparation when no assignment is possible. Different solution...

  3. A dynamic transformation method for modal synthesis.

    Science.gov (United States)

    Kuhar, E. J.; Stahle, C. V.

    1973-01-01

    This paper presents a condensation method for large discrete parameter vibration analysis of complex structures that greatly reduces truncation errors and provides accurate definition of modes in a selected frequency range. A dynamic transformation is obtained from the partitioned equations of motion that relates modes not explicity in the condensed solution to the retained modes at a selected system frequency. The generalized mass and stiffness matrices, obtained with existing modal synthesis methods, are reduced using this transformation and solved. Revised solutions are then obtained using new transformations at the calculated eigenvalues and are also used to assess the accuracy of the results. If all the modes of interest have not been obtained, the results are used to select a new set of retained coordinates and a new transformation frequency, and the procedure is repeated for another group of modes.

  4. [Study on the effect of temperature on the conformation of cross-linked collagen by two-dimensional infrared correlation spectroscopy].

    Science.gov (United States)

    Chen, Yi-Hui; Tian, Hui-Lin; Li, Ji-Heng; Li, Guo-Ying

    2012-06-01

    The Fourier transform infrared spectroscopy and two dimensional correlation analysis method were applied to study a denaturing process of uncross-linked collagen and cross-linked collagen during varying temperature. It was found that the intensity of typically characteristic absorptions of collagen decreased and its peak shifted to low frequency, The amide II central absorbance peak moved to a lower frequency by about 10 cm(-1), which indicated that the inter-chain hydrogen bonds which stabilized the triple helix conformation of collagen were disrupted during thermal denaturation, resulting in a conformational change. The intensity of auto-peak at 1 515 cm(-1) was maximum, which suggested that the temperature had a big impact on amide II. In comparison with uncross-linked collagen, the intensity of cross-peaks of cross-linked collagen was weaker, which demonstrated that the effect of temperature on the structure of cross-linked collagen was smaller, and the thermal stability properties of collagen solution could be improved by cross-linking. While the order of second structure changes of cross-linked collagen was different. These fundamental data should provide available information for understanding the relationship between the structure and function of cross-linked collagen.

  5. Transforming giants.

    Science.gov (United States)

    Kanter, Rosabeth Moss

    2008-01-01

    Large corporations have long been seen as lumbering, inflexible, bureaucratic--and clueless about global developments. But recently some multinationals seem to be transforming themselves: They're engaging employees, moving quickly, and introducing innovations that show true connection with the world. Harvard Business School's Kanter ventured with a research team inside a dozen global giants--including IBM, Procter & Gamble, Omron, CEMEX, Cisco, and Banco Real--to discover what has been driving the change. After conducting more than 350 interviews on five continents, she and her colleagues came away with a strong sense that we are witnessing the dawn of a new model of corporate power: The coordination of actions and decisions on the front lines now appears to stem from widely shared values and a sturdy platform of common processes and technology, not from top-down decrees. In particular, the values that engage the passions of far-flung workforces stress openness, inclusion, and making the world a better place. Through this shift in what might be called their guidance systems, the companies have become as creative and nimble as much smaller ones, even while taking on social and environmental challenges of a scale that only large enterprises could attempt. IBM, for instance, has created a nonprofit partnership, World Community Grid, through which any organization or individual can donate unused computing power to research projects and see what is being done with the donation in real time. IBM has gained an inspiring showcase for its new technology, helped business partners connect with the company in a positive way, and offered individuals all over the globe the chance to contribute to something big.

  6. Signals and transforms in linear systems analysis

    CERN Document Server

    Wasylkiwskyj, Wasyl

    2013-01-01

    Signals and Transforms in Linear Systems Analysis covers the subject of signals and transforms, particularly in the context of linear systems theory. Chapter 2 provides the theoretical background for the remainder of the text. Chapter 3 treats Fourier series and integrals. Particular attention is paid to convergence properties at step discontinuities. This includes the Gibbs phenomenon and its amelioration via the Fejer summation techniques. Special topics include modulation and analytic signal representation, Fourier transforms and analytic function theory, time-frequency analysis and frequency dispersion. Fundamentals of linear system theory for LTI analogue systems, with a brief account of time-varying systems, are covered in Chapter 4 . Discrete systems are covered in Chapters 6 and 7.  The Laplace transform treatment in Chapter 5 relies heavily on analytic function theory as does Chapter 8 on Z -transforms. The necessary background on complex variables is provided in Appendix A. This book is intended to...

  7. Thermal Analyse sof Cross-Linked Polyethylene

    Directory of Open Access Journals (Sweden)

    Radek Polansky

    2007-01-01

    Full Text Available The paper summarizes results obtained during the structural analyses measurements (Differential Scanning Calorimetry DSC, Thermogravimetry TG, Thermomechanical analysis TMA and Fourier transform infrared spectroscopy FT-IR. The samples of cross-linked polyethylene cable insulation were tested via these analyses. The DSC and TG were carried out using simultaneous thermal analyzer TA Instruments SDT Q600 with connection of Fourier transform infrared spectrometer Nicolet 380. Thermomechanical analysis was carried out by TMA Q400EM TA Instruments apparatus.

  8. Rain rate intensity model for communication link design across the Indian region

    Science.gov (United States)

    Kilaru, Aravind; Kotamraju, Sarat K.; Avlonitis, Nicholas; Sri Kavya, K. Ch.

    2016-07-01

    A study on rain statistical parameters such as one minute rain intensity, possible number of minute occurrences with respective percentage of time in a year has been evaluated for the purpose of communication link design at Ka, Q, V bands as well as at Free-Space Optical communication links (FSO). To understand possible outage period of a communication links due to rainfall and to investigate rainfall pattern, Automatic Weather Station (AWS) rainfall data is analysed due its ample presence across India. The climates of the examined AWS regions vary from desert to cold climate, heavy rainfall to variable rainfall regions, cyclone effective regions, mountain and coastal regions. In this way a complete and unbiased picture of the rainfall statistics for Indian region is evaluated. The analysed AWS data gives insight into yearly accumulated rainfall, maximum hourly accumulated rainfall, mean hourly accumulated rainfall, number of rainy days and number of rainy hours from 668 AWS locations. Using probability density function the one minute rainfall measurements at KL University is integrated with AWS measurements for estimating number of rain occurrences in terms of one minute rain intensity for annual rainfall accumulated between 100 mm and 5000 mm to give an insight into possible one minute accumulation pattern in an hour for comprehensive analysis of rainfall influence on a communication link for design engineers. So that low availability communications links at higher frequencies can be transformed into a reliable and economically feasible communication links for implementing High Throughput Services (HTS).

  9. Application of Distribution Power Electronic Transformer for Medium Voltage

    Directory of Open Access Journals (Sweden)

    Prashant Kumar

    2014-12-01

    Full Text Available In   this   paper   a   distribution   power electronic transformer (DPET for feeding critical loads is presented. The PE based transformer is a multi-port converter that can connect to medium voltage levels on the primary side. Bidirectional power flow is provided to the each module. The presented structure consists of three stages: an input stage, an isolation stage, and an output stage.  The input current is sinusoidal, and it converts the high AC input voltage to low DC voltages. The isolated DC/DC converters are then connected to the DC links and provide galvanic isolation between the HV and LV sides. Finally, a three-phase inverter generates the AC output with the desired amplitude and frequency. The proposed DPET is extremely modular and can be extended for different voltage and power levels. It performs typical functions and has advantages such as power factor correction, elimination of voltage sag and swell, and reduction of voltage flicker in load side. Also in comparison to conventional transformers, it has lower weight, lower volume and eliminates necessity for toxic dielectric coolants the DPET performance is verified in MATLAB simulation.

  10. Frequency conversion of structured light

    CERN Document Server

    Steinlechner, Fabian; Pruneri, Valerio; Torres, Juan P

    2015-01-01

    We demonstrate the coherent frequency conversion of structured light, optical beams in which the phase varies in each point of the transverse plane, from the near infrared (803nm) to the visible (527nm). The frequency conversion process makes use of sum-frequency generation in a periodically poled lithium niobate (ppLN) crystal with the help of a 1540-nm Gaussian pump beam. We perform far-field intensity measurements of the frequency-converted field, and verify the sought-after transformation of the characteristic intensity and phase profiles for various input modes. The coherence of the frequency-conversion process is confirmed using a mode-projection technique with a phase mask and a single-mode fiber. The presented results could be of great relevance to novel applications in high-resolution microscopy and quantum information processing.

  11. Transformation of plant young proembryos by electroporation

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    It is first reported that plant young proembryos expressed exogenous reporter genes by electroporation. Young proembryos with 8-32 cells and globular proembryos with 250-400 cells could be isolated by enzymatic maceration combined with microdissection. After electroporation with GUS or GFP genes, the proembryos were cultured for 1-2 d in KM8p medium. At the field strength of electroporation 500-1 500 V/cm, blue reaction of GUS or green fluorescence of GFP could be observed in the proembryos. The highest transient expression frequency of young proembryos (2.2%) was obtained at the field strength of 750 V/cm, whereas the highest frequency of globular proembryos (5.9%) was obtained at the field strength of 1 250 V/cm. Taking the proportion of transformed cells in the whole cells of proembryos as efficient transformation frequency, the efficient transformation frequency of the young proembryos was 7 times that of the globular proembryos.

  12. Linked alternating forms and linked symplectic Grassmannians

    CERN Document Server

    Osserman, Brian

    2011-01-01

    Motivated by applications to higher-rank Brill-Noether theory and the Bertram-Feinberg-Mukai conjecture, we introduce the concepts of linked alternating and linked symplectic forms on a chain of vector bundles, and show that the linked symplectic Grassmannians parametrizing chains of subbundles isotropic for a given linked symplectic form has good dimensional behavior analogous to that of the classical symplectic Grassmannian.

  13. Materializing the web of linked data

    CERN Document Server

    Konstantinou, Nikolaos

    2015-01-01

    This book explains the Linked Data domain by adopting a bottom-up approach: it introduces the fundamental Semantic Web technologies and building blocks, which are then combined into methodologies and end-to-end examples for publishing datasets as Linked Data, and use cases that harness scholarly information and sensor data. It presents how Linked Data is used for web-scale data integration, information management and search. Special emphasis is given to the publication of Linked Data from relational databases as well as from real-time sensor data streams. The authors also trace the transformation from the document-based World Wide Web into a Web of Data. Materializing the Web of Linked Data is addressed to researchers and professionals studying software technologies, tools and approaches that drive the Linked Data ecosystem, and the Web in general.

  14. Microwave to Optical Link Using an Optical Microresonator

    CERN Document Server

    Jost, J D; Lecaplain, C; Brasch, V; Pfeiffer, M H P; Kippenberg, T J

    2014-01-01

    The ability to phase coherently link optical to radio frequencies with femtosecond modelocked lasers has enabled counting cycles of light and is the basis of optical clocks, absolute frequency synthesis, tests of fundamental physics, and improved spectroscopy. Using an optical microresonator frequency comb to establish a coherent link promises to greatly extend optical frequency synthesis and measurements to areas requiring compact form factor, on chip integration and repetition rates in the microwave regime, including coherent telecommunications, astrophysical spectrometer calibration or microwave photonics. Here we demonstrate for the first time a microwave to optical link using a microresonator. Using a temporal dissipative single soliton state in an ultra high Q crystalline microresonator an optical frequency comb is generated that is self-referenced, allowing to phase coherently link a 190 THZ optical carrier directly to a 14 GHz microwave frequency. Our work demonstrates that precision optical frequency...

  15. Polarity of localised conversion in Streptococcus pneumoniae transformation.

    Science.gov (United States)

    Mostachfi, P; Sicard, A M

    1987-06-01

    Localised conversion in pneumococcal transformation is a process that spans a few nucleotides when the 5'-ATTAAT/3'-TAAGTA configuration occurs at the pairing step. It was first observed in two-point crosses between an amiA mutation (amiA36) carrying this sequence and other closely linked mutants of the locus. The yield of the amiA resistance allele conversion to wild type is 20%. In order to characterize this process, which differs from long-patch conversion by the length of DNA repair, gene requirements and sequence specificity, we devised experiments to detect the reciprocal conversion, AmiA+ to AmiAr. For this purpose we examined the suppressibility by a pneumococcal informational suppressor of several nonsense mutations at the locus. Amber (UAG) and ochre (UAA) mutations are suppressed whereas UGA is not suppressed. In this genetic background, where amiA36 is partly suppressed, it was possible to select for double mutants in a cross between amiA36 and a closely linked non-suppressible marker. Direct isolation of such double mutants was also performed without any screening in crosses between amiA36 and the same linked marker in cloned DNA. The frequency of double mutants was very low (1/175) suggesting that there is no conversion of wild-type to mutant alleles. Thus conversion is a polarized process changing specifically A to C.

  16. A Distributed Model of Four-Port Monolithic Transformer

    OpenAIRE

    Lee, Dong Ho; Ko, Sangsoo; Jeon, Sang-Hoon; Park, Jae-Woo; Hong, Songcheol

    2004-01-01

    This paper deals with modeling of a monolithic spiral transformer. The transformer is designed and fabricated as a symmetrical octagonal spiral structure using two-metal layer process on GaAs substrate for input balun applications of 2 GHz and 5 GHz push-pull power amplifiers. A distributed model of the transformer is developed to fit in wide frequency range with four ports. The model includes the skin effect which describes increase in series resistance with frequency. Six different se...

  17. A More Accurate Fourier Transform

    CERN Document Server

    Courtney, Elya

    2015-01-01

    Fourier transform methods are used to analyze functions and data sets to provide frequencies, amplitudes, and phases of underlying oscillatory components. Fast Fourier transform (FFT) methods offer speed advantages over evaluation of explicit integrals (EI) that define Fourier transforms. This paper compares frequency, amplitude, and phase accuracy of the two methods for well resolved peaks over a wide array of data sets including cosine series with and without random noise and a variety of physical data sets, including atmospheric $\\mathrm{CO_2}$ concentrations, tides, temperatures, sound waveforms, and atomic spectra. The FFT uses MIT's FFTW3 library. The EI method uses the rectangle method to compute the areas under the curve via complex math. Results support the hypothesis that EI methods are more accurate than FFT methods. Errors range from 5 to 10 times higher when determining peak frequency by FFT, 1.4 to 60 times higher for peak amplitude, and 6 to 10 times higher for phase under a peak. The ability t...

  18. Time-Frequency Based Channel Estimation for High-Mobility OFDM Systems-Part I: MIMO Case

    Science.gov (United States)

    Önen, Erol; Akan, Aydın; Chaparro, LuisF

    2010-12-01

    Multiple-input multiple-output (MIMO) systems hold the potential to drastically improve the spectral efficiency and link reliability in future wireless communications systems. A particularly promising candidate for next-generation fixed and mobile wireless systems is the combination of MIMO technology with Orthogonal Frequency Division Multiplexing (OFDM). OFDM has become the standard method because of its advantages over single carrier modulation schemes on multipath, frequency selective fading channels. Doppler frequency shifts are expected in fast-moving environments, causing the channel to vary in time, that degrades the performance of OFDM systems. In this paper, we present a time-varying channel modeling and estimation method based on the Discrete Evolutionary Transform to obtain a complete characterization of MIMO-OFDM channels. Performance of the proposed method is evaluated and compared on different levels of channel noise and Doppler frequency shifts.

  19. Low Voltage Power Supply Incorporating Ceramic Transformer

    CERN Document Server

    Imori, M

    2007-01-01

    A low voltage power supply provides the regulated output voltage of 1 V from the supply voltage around 48 V. The low voltage power supply incorporates a ceramic transformer which utilizes piezoelectric effect to convert voltage. The ceramic transformer isolates the secondary from the primary, thus providing the ground isolation between the supply and the output voltages. The ceramic transformer takes the place of the conventional magnetic transformer. The ceramic transformer is constructed from a ceramic bar and does not include any magnetic material. So the low voltage power supply can operate under a magnetic field. The output voltage is stabilized by feedback. A feedback loop consists of an error amplifier, a voltage controlled oscillator and a driver circuit. The amplitude ratio of the transformer has dependence on the frequency, which is utilized to stabilize the output voltage. The low voltage power supply is investigated on the analogy of the high voltage power supply similarly incorporating the cerami...

  20. The Linear Time Frequency Analysis Toolbox

    DEFF Research Database (Denmark)

    Søndergaard, Peter Lempel; Torrésani, Bruno; Balazs, Peter

    2011-01-01

    The Linear Time Frequency Analysis Toolbox is a Matlab/Octave toolbox for computational time-frequency analysis. It is intended both as an educational and computational tool. The toolbox provides the basic Gabor, Wilson and MDCT transform along with routines for constructing windows (lter...

  1. DOPPLERLET BASED TIME-FREQUENCY REPRESENTATION VIA MATCHING PURSUITS

    Institute of Scientific and Technical Information of China (English)

    Zou Hongxing; Zhou Xiaobo; Dai Qionghai; Li Yanda

    2001-01-01

    A new time-frequency representation called Dopplerlet transform, which uses the dilated, translated and modulated windowed Doppler signals as its basis functions, is proposed, and the Fourier transform, short-time Fourier transform (including Gabor transform), wavelet transform, and chirplet transform are formulated in one framework of Dopplerlet transform accordingly.It is proved that the matching pursuits based on Dopplerlet basis functions are convergent, and that the energy of residual signals yielded in the decomposition process decays exponentially. Simulation results show that the matching pursuits with Dopplerlet basis functions can characterize compactly a nonstationary signal.

  2. Agrobacterium-mediated transformation in chickpea (Cicer arietinum L.) with an insecticidal protein gene: optimisation of different factors.

    Science.gov (United States)

    Indurker, Shivani; Misra, Hari S; Eapen, Susan

    2010-07-01

    Agrobacterium-mediated transformation in chickpea was developed using strain LBA4404 carrying nptII, uidA and cryIAc genes and transformants selected on Murashige and Skoog's basal medium supplemented with benzyladenine, kinetin and kanamycin. Integration of transgenes was demonstrated using polymerase chain reaction and Southern blot hybridization of T0 plants. The expression of CryIAc delta endotoxin and GUS enzyme was shown by enzyme linked immunosorbent assay and histochemical assay respectively. The transgenic plants (T0) showed more tolerance to infection by Helicoverpa armigera compared to control plants. Various factors such as explant source, cultivar type, different preculture treatment period of explants, co-cultivation period, acetosyringone supplementation, Agrobacterium harboring different plasmids, vacuum infiltration and sonication treatment were tested to study the influence on transformation frequency. The results indicated that use of epicotyl as explant, cultivar ICCC37, Agrobacterium harboring plasmid pHS102 as vector, preculture of explant for 48 h, co-cultivation period of 2 days at 25°C and vacuum infiltration for 15 min produced the best transformation results. Sonication treatment of explants with Agrobacteria for 80 s was found to increase the frequency of transformation.

  3. High-frequency magnetic components

    CERN Document Server

    Kazimierczuk, Marian K

    2013-01-01

    A unique text on the theory and design fundaments of inductors and transformers, updated with more coverage on the optimization of magnetic devices and many new design examples The first edition is popular among a very broad audience of readers in different areas of engineering and science. This book covers the theory and design techniques of the major types of high-frequency power inductors and transformers for a variety of applications, including switching-mode power supplies (SMPS) and resonant dc-to-ac power inverters and dc-to-dc power converters. It describes eddy-current phenomena (su

  4. Frequency domain processing of on-chip biphoton frequency comb

    CERN Document Server

    Jaramillo-Villegas, Jose A; Odele, Ogaga D; Leaird, Daniel E; Ou, Zhe-Yu; Qi, Minghao; Weiner, Andrew M

    2016-01-01

    Quantum information processing (QIP) promises to improve the security of our communications as well as to solve some algorithms with exponential complexity in polynomial time. Biphotons have been demonstrated as one of the most promising platforms for real implementations of QIP systems. In particular, time-bin entangled photons have been used for implementations of quantum gates which require highly stable interferometers. On the other hand, frequency-bin entanglement has been proposed to avoid the use of interferometers and the complexity of their stabilization, which potentially makes the implementation of quantum gates highly scalable. Through Fourier transform pulse shaping and electro-optic modulation, there has been a wide range of experiments that show control of entangled photons in the frequency domain. In addition, biphoton frequency combs (BFC) have also been generated using bulk optics and frequency filtering of broadband continuous biphoton spectra. However, on-chip entangled photon pair generat...

  5. Heterospecific transformation among cyanobacteria.

    OpenAIRE

    Stevens, S. E.; Porter, R D

    1986-01-01

    Heterospecific transformation occurred between cyanobacteria currently classified in either the genus Synechococcus or Synechocystis. Cyanobacterial strains 73109 and 6906 were capable of physiological transformation.

  6. Heterospecific transformation among cyanobacteria.

    OpenAIRE

    Stevens, S E; Porter, R D

    1986-01-01

    Heterospecific transformation occurred between cyanobacteria currently classified in either the genus Synechococcus or Synechocystis. Cyanobacterial strains 73109 and 6906 were capable of physiological transformation.

  7. Phase-transformation in iron oxide and formation of Cu/γ-Fe2O3 nanocomposite using radio-frequency sputtering with metal chips on an α-Fe2O3 target

    Science.gov (United States)

    Abe, Seishi; Watanabe, Masato

    2017-07-01

    A simple technique that uses radio-frequency sputtering with a functional element on a hematite (α-Fe2O3) target is presented for the production of maghemite (γ-Fe2O3) thin films. These films are prepared on water-cooled glass substrates in an Ar atmosphere. Investigations are done with Ti, Si, Al, Cu, Mo, and Zn, with γ-Fe2O3 being obtained only in the presence of Cu, indicating that phase transition occurs only for this metal. Mössbauer spectra and magnetization analysis reveal that the quality of the obtained γ-Fe2O3 films is higher than that of the film produced using Mg, which was reported in our previous work. High-angle annular dark-field scanning tunneling electron microscopy and electron energy-loss spectroscopy reveal that the added Cu remains in a metallic state (without oxidization), forming a Cu/γ-Fe2O3 phase-mixture in the as-deposited film. The Cu/γ-Fe2O3 composite film exhibits negative magnetoresistance (MR), with a MR ratio of approximately 0.6% at room temperature in an applied field of 10 kOe, and a negative Faraday rotation of -5708 deg cm-1 at 830 nm.

  8. Genome-wide profiling of genetic variation in Agrobacterium-transformed rice plants*#

    Science.gov (United States)

    Li, Wen-xu; Wu, San-ling; Liu, Yan-hua; Jin, Gu-lei; Zhao, Hai-jun; Fan, Long-jiang; Shu, Qing-yao

    2016-01-01

    Agrobacterium-mediated transformation has been widely used in producing transgenic plants, and was recently used to generate “transgene-clean” targeted genomic modifications coupled with the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas9) system. Although tremendous variation in morphological and agronomic traits, such as plant height, seed fertility, and grain size, was observed in transgenic plants, the underlying mechanisms are not yet well understood, and the types and frequency of genetic variation in transformed plants have not been fully disclosed. To reveal the genome-wide variation in transformed plants, we sequenced the genomes of five independent T0 rice plants using next-generation sequencing (NGS) techniques. Bioinformatics analyses followed by experimental validation revealed the following: (1) in addition to transfer-DNA (T-DNA) insertions, three transformed plants carried heritable plasmid backbone DNA of variable sizes (855–5216 bp) and in different configurations with the T-DNA insertions (linked or apart); (2) each transgenic plant contained an estimated 338–1774 independent genetic variations (single nucleotide variations (SNVs) or small insertion/deletions); and (3) 2–6 new Tos17 insertions were detected in each transformed plant, but no other transposable elements or bacterial genomic DNA. PMID:27921404

  9. Algorithm, applications and evaluation for protein comparison by Ramanujan Fourier transform.

    Science.gov (United States)

    Zhao, Jian; Wang, Jiasong; Hua, Wei; Ouyang, Pingkai

    2015-12-01

    The amino acid sequence of a protein determines its chemical properties, chain conformation and biological functions. Protein sequence comparison is of great importance to identify similarities of protein structures and infer their functions. Many properties of a protein correspond to the low-frequency signals within the sequence. Low frequency modes in protein sequences are linked to the secondary structures, membrane protein types, and sub-cellular localizations of the proteins. In this paper, we present Ramanujan Fourier transform (RFT) with a fast algorithm to analyze the low-frequency signals of protein sequences. The RFT method is applied to similarity analysis of protein sequences with the Resonant Recognition Model (RRM). The results show that the proposed fast RFT method on protein comparison is more efficient than commonly used discrete Fourier transform (DFT). RFT can detect common frequencies as significant feature for specific protein families, and the RFT spectrum heat-map of protein sequences demonstrates the information conservation in the sequence comparison. The proposed method offers a new tool for pattern recognition, feature extraction and structural analysis on protein sequences.

  10. Equipment selection heuristics for microwave fixed links

    Science.gov (United States)

    Flood, I. D.; Allen, S. M.

    2014-08-01

    Microwave fixed links use highly standardized radio equipment and, in the radio equipment standard referenced in this paper, there is a choice between exactly two radio systems when the assigner wishes to resolve a specific data rate exactly: one using a relatively lower-order modulation scheme and one a relatively higher-order scheme. Although the higher-order equipment requires less bandwidth for an isolated link, these systems radiate at higher powers and require larger protection ratios in the radio interference environment which lead to well-established trade-offs between modulation, bandwidth, equivalent isotropic radiated power, and frequency assignment criteria. Our earlier research showed that by extending the Frequency Assignment Problem to include equipment selection and using lower-order modulation equipment on selected links, we can actually reduce the overall span of frequencies required for a network frequency assignment. This work focused on the development of integer programming formulations and analyzed the exact solutions obtained. Exact solutions are impractical for real world problems; hence, here we focus on the development of heuristics for equipment selection. We can model the fixed link network as a complete graph where the vertices represent fixed link frequency assignment requests and the edges represent interference between pairs of vertices. Using a graph theoretic analysis of the interference problem, we propose heuristic techniques and discuss the relative success of our approach in this article.

  11. Modelo práctico del transformador de distribución trifásico para análisis de transitorios de baja frecuencia: Identificación de parámetros Practical model of three-phase distribution transformer for low-frequency transients analysis: Parameter identification

    Directory of Open Access Journals (Sweden)

    Jorge E Celis-Montero

    2012-12-01

    Full Text Available Para el análisis de los fenómenos transitorios que se originan durante la operación de los transformadores eléctricos, se pueden emplear los modelos implantados en las herramientas de simulación tipo EMTP. Algunos de estos modelos requieren la especificación de parámetros que son difíciles de obtener a partir de ensayo como la característica de saturación de las piernas y los yugos, debido a la interconexión predeterminada de los devanados, o que pueden ser propiedad de los fabricantes de transformadores como las dimensiones relativas del núcleo. En este artículo se propone un modelo para el transformador trifásico de tres columnas que es útil para el análisis de transitorios de baja frecuencia y cuyos parámetros pueden ser determinados mediante pruebas de laboratorio convencionales. El modelo ha sido implantado en EMTP y validado por comparación de resultados obtenidos por simulación con resultados derivados mediante pruebas de laboratorio.In order to analyse transient phenomena originated during electrical transformers operation, models implemented in simulation tools EMTP-type can be used. Some of these models need the specification of parameters that can be difficult to obtain by testing, such as the saturation characteristic of the legs and the yokes, due to the predetermined interconnection of the windings or might be property of transformer's manufacturers, such as the relative dimensions of the core. This paper proposes a three-phase three-legged transformer model that can be used for analysis of low-frequency transients and whose parameters can be determined using conventional laboratory tests. The model has been implemented in an EMTP-type program and validated by comparing simulation results with real measurements obtained from laboratory tests.

  12. 基于小波变换的长距离光正交频分复用系统中四波混频引起的相位噪声分析%Analysis of Phase Noise Induced by Four-Wave Mixing in Long-Haul Optical Orthogonal Frequency-Division Multiplexing Based on Wavelet Transforms

    Institute of Scientific and Technical Information of China (English)

    高海越; 潘炜

    2012-01-01

    四波混频(FWM)效应是相干光正交频分复用(CO-OFDM)系统中最主要的非线性作用.分析基于小波变换的相干光正交频分(WT-OOFDM)系统原理,研究小波变换对FWM效应和光放大器自发辐射(ASE)引起的相位噪声的改善效果.数值结果表明,在采用常规G.652光纤,100 Gbit/s的WT-OOFDM传输1500 km时,非线性相位噪声降低20%,总相位噪声降低15%.%Four-wave mixing (FWM) is the most important nonlinear effect in coherent optical orthogonal frequency-division multiplexing (CO-OFDM) system. The principle of CO-OFDM system based on wavelet transforms (WT-OOFDM) is analyzed, and effect of wavelet transforms on phase noise caused by FWM and amplified spontaneous emission CASE) of optical amplifiers is discussed. For the conventional optical fiber G. 652, 100 Gbit/s WT-OOFDM system, the simulation results show that the variance of the total phase noise can be decreased by 15% , and the nonlinear phase noise has a 20% reduction while the transmission distance reaches 1500 km.

  13. Subband/Transform MATLAB Functions For Processing Images

    Science.gov (United States)

    Glover, D.

    1995-01-01

    SUBTRANS software is package of routines implementing image-data-processing functions for use with MATLAB*(TM) software. Provides capability to transform image data with block transforms and to produce spatial-frequency subbands of transformed data. Functions cascaded to provide further decomposition into more subbands. Also used in image-data-compression systems. For example, transforms used to prepare data for lossy compression. Written for use in MATLAB mathematical-analysis environment.

  14. Subband/Transform MATLAB Functions For Processing Images

    Science.gov (United States)

    Glover, D.

    1995-01-01

    SUBTRANS software is package of routines implementing image-data-processing functions for use with MATLAB*(TM) software. Provides capability to transform image data with block transforms and to produce spatial-frequency subbands of transformed data. Functions cascaded to provide further decomposition into more subbands. Also used in image-data-compression systems. For example, transforms used to prepare data for lossy compression. Written for use in MATLAB mathematical-analysis environment.

  15. Detection and Acceptance of DC High Frequency Switch Power Supply in the Transformer Substation%变电站直流高频开关电源的检测与验收

    Institute of Scientific and Technical Information of China (English)

    张卫平

    2015-01-01

    直流系统可靠与否直接关系到电网的安全,随着高频开关直流电源系统大量使用,该种电源系统的建成投运验收交接和运行检测、检查,已显得极为重要,从柜体、元器件外观的检查、整套系统电气技术参数检测都必须严格进行,并根据不同的目的进行相应项目的检查,运行中更应定期检查,及时发现存在的隐患,保证其在规定的参数下运行,以提高电池的服役年限。%The reliability of DC system is directly related to the safety of the power grid. With the heavy use of DC power system of high-frequency switch, the built, operation, acceptance, handover and running, detection, checking of this kind of power system are extremely important. The appearance checking of cabinets and components, the electrical technology parameters of the whole system must be rigorously conducted, and according to the different goals to check the related objects. The periodical inspection in operation is necessary to find the wooden horse in time to ensure the running under specified parameters and improve the service life of the battery.

  16. Mitigation of voltage sag, swell and power factor correction using solid-state transformer b

    Directory of Open Access Journals (Sweden)

    M.R. Banaei

    2014-09-01

    Full Text Available This paper presents a novel topology of solid-state transformer (SST. In the design process, the AC/DC, DC/AC and AC/AC converters have been integrated to achieve higher efficiency. To obtain higher efficiency from other SST with DC-link topologies, the AC/DC and DC/AC converters have been integrated in one matrix converter. The proposed SST performs typical functions and has advantages such as power factor correction, voltage sag and swell elimination, voltage flicker reduction and protection capability in fault situations. In addition, it has other benefits such as light weight, low volume and elimination of hazardous liquid dielectrics because it uses medium frequency transformer. The operation and some performances of the proposed SST have been verified by the simulation results.

  17. Women's Empowerment and Education: Linking Knowledge to Transformative Action

    Science.gov (United States)

    Stromquist, Nelly P.

    2015-01-01

    Women's empowerment is a concept that has acquired substantial recognition in the past decade. However, it is better known among international development organisations, NGOs, and grassroots groups than in academic circles. This article examines the concept of women's empowerment as a foundational element in a theory of social change in which the…

  18. Women's Empowerment and Education: Linking Knowledge to Transformative Action

    Science.gov (United States)

    Stromquist, Nelly P.

    2015-01-01

    Women's empowerment is a concept that has acquired substantial recognition in the past decade. However, it is better known among international development organisations, NGOs, and grassroots groups than in academic circles. This article examines the concept of women's empowerment as a foundational element in a theory of social change in which the…

  19. Design of Basis Functions for Transform Domain Communication Systems Using Time-Frequency Analysis%采用时频分析的变换域通信系统基函数设计

    Institute of Scientific and Technical Information of China (English)

    谢铁城; 达新宇; 褚振勇; 曾武; 王舒

    2012-01-01

    为使变换域通信系统基函数充分利用背景信号的频谱分布信息以进一步提高系统抗干扰能力,提出了采用多进制序列设计基函数幅度谱的方法.首先在干扰存在的条件下,对单码片成型基函数调制及解调信号的短时频谱特性进行分析,由此推导出系统误码率的解析表达式,将求解系统误码率解析式的最优化问题转化为求最大信号干扰噪声比问题,利用随机相位的均匀分布特性对最大信号干扰噪声比问题进行求解,从而得到多进制序列基函数.仿真结果表明:该系统具有更好的抗干扰性能,在高干信比条件下也具有良好的通信效果;当干信比为25~41 dB且信噪比为-6~3 dB时,系统误码率均低于二元序列基函数的系统误码率;干信比为36 dB、信噪比为O dB 时,系统误码率可低于10-4.%It is an effective way to improve the system anti-jammer ability that the basis function of a transform domain communication system (TDCS) is constructed by making full use of the distributing information of spectrum of background signal. According to the principle, a method to design the basis function is proposed by utilizing array sequences to express the spectrum amplitude. With the coexistence of jamming, the short-term spectra of both the single-chip waveform coded basis function modulated signal and the demodulated signal are studied, and then the analytical expression of bit error rate(BER) is derived obtained. The optimization solution of BER is converted into the calculation of the maximum signal-to-interference-plus-noise ratio (SINR). The maximum SINR problem is solved by using the uniform distribution property of random phase, and the new basis function is obtained. Simulation results show that the proposed system exhibits a better anti-jammer performance and has an excellent performance under the condition of high jamming-to-signal ratio. When the interference-to-signal is 25-41 dB and the

  20. Multi-Functional Fibre-Optic Microwave Links

    DEFF Research Database (Denmark)

    Gliese, Ulrik Bo

    1998-01-01

    The multi-functionality of microwave links based on remote heterodyne detection of signals from a dual-frequency laser transmitter is discussed and experimentally demonstrated in this paper. Typically, direct detection in conjunction with optical intensity modulation is used to implement fibre......-optic microwave links. The resulting links are inherently transparent and mainly used for signal transmission. As opposed to direct detection links, remote heterodyne detection links can directly perform functionalities such as modulation, frequency conversion, and transparent signal recovery in addition...

  1. General Υ-transformations

    DEFF Research Database (Denmark)

    Barndorff-Nielsen, Ole Eiler; Rosinski, Jan; Thorbjørnsen, Steen

    In this paper we introduce a general class of transformations of (all or most of) the class ML(Rd), of d-dimensional Lévy measures on Rd, into itself. We refer to transformations of this type as Υ transformations (or Upsilon transformations). Closely associated to these are mappings of the set ID...

  2. Negotiated Grammar Transformation

    NARCIS (Netherlands)

    Zaytsev, V.

    2012-01-01

    In this paper, we study controlled adaptability of metamodel transformations. We consider one of the most rigid metamodel transformation formalisms — automated grammar transformation with operator suites, where a transformation script is built in such a way that it is essentially meant to be applica

  3. On Hurwitz transformations

    CERN Document Server

    Hassan, M H; Hassan, M Hage; Kibler, M

    1994-01-01

    A bibliography on the Hurwitz transformations is given. We deal here, with some details, with two particular Hurwitz transformations, viz, the \\grq \\to \\grt Kustaanheimo-Stiefel transformation and its \\grh \\to \\grc compact extension. These transformations are derived in the context of Fock-Bargmann-Schwinger calculus with special emphasis on angular momentum theory.

  4. Generalized Fourier transforms classes

    DEFF Research Database (Denmark)

    Berntsen, Svend; Møller, Steen

    2002-01-01

    The Fourier class of integral transforms with kernels $B(\\omega r)$ has by definition inverse transforms with kernel $B(-\\omega r)$. The space of such transforms is explicitly constructed. A slightly more general class of generalized Fourier transforms are introduced. From the general theory...

  5. Linked data management

    CERN Document Server

    Hose, Katja; Schenkel, Ralf

    2014-01-01

    Linked Data Management presents techniques for querying and managing Linked Data that is available on today’s Web. The book shows how the abundance of Linked Data can serve as fertile ground for research and commercial applications. The text focuses on aspects of managing large-scale collections of Linked Data. It offers a detailed introduction to Linked Data and related standards, including the main principles distinguishing Linked Data from standard database technology. Chapters also describe how to generate links between datasets and explain the overall architecture of data integration systems based on Linked Data. A large part of the text is devoted to query processing in different setups. After presenting methods to publish relational data as Linked Data and efficient centralized processing, the book explores lookup-based, distributed, and parallel solutions. It then addresses advanced topics, such as reasoning, and discusses work related to read-write Linked Data for system interoperation. Desp...

  6. Wavelet transform based watermark for digital images.

    Science.gov (United States)

    Xia, X G; Boncelet, C; Arce, G

    1998-12-07

    In this paper, we introduce a new multiresolution watermarking method for digital images. The method is based on the discrete wavelet transform (DWT). Pseudo-random codes are added to the large coefficients at the high and middle frequency bands of the DWT of an image. It is shown that this method is more robust to proposed methods to some common image distortions, such as the wavelet transform based image compression, image rescaling/stretching and image halftoning. Moreover, the method is hierarchical.

  7. Applications of a fast, continuous wavelet transform

    Energy Technology Data Exchange (ETDEWEB)

    Dress, W.B.

    1997-02-01

    A fast, continuous, wavelet transform, based on Shannon`s sampling theorem in frequency space, has been developed for use with continuous mother wavelets and sampled data sets. The method differs from the usual discrete-wavelet approach and the continuous-wavelet transform in that, here, the wavelet is sampled in the frequency domain. Since Shannon`s sampling theorem lets us view the Fourier transform of the data set as a continuous function in frequency space, the continuous nature of the functions is kept up to the point of sampling the scale-translation lattice, so the scale-translation grid used to represent the wavelet transform is independent of the time- domain sampling of the signal under analysis. Computational cost and nonorthogonality aside, the inherent flexibility and shift invariance of the frequency-space wavelets has advantages. The method has been applied to forensic audio reconstruction speaker recognition/identification, and the detection of micromotions of heavy vehicles associated with ballistocardiac impulses originating from occupants` heart beats. Audio reconstruction is aided by selection of desired regions in the 2-D representation of the magnitude of the transformed signal. The inverse transform is applied to ridges and selected regions to reconstruct areas of interest, unencumbered by noise interference lying outside these regions. To separate micromotions imparted to a mass-spring system (e.g., a vehicle) by an occupants beating heart from gross mechanical motions due to wind and traffic vibrations, a continuous frequency-space wavelet, modeled on the frequency content of a canonical ballistocardiogram, was used to analyze time series taken from geophone measurements of vehicle micromotions. By using a family of mother wavelets, such as a set of Gaussian derivatives of various orders, features such as the glottal closing rate and word and phrase segmentation may be extracted from voice data.

  8. Synchrosqueezed wavelet transform for damping identification

    Science.gov (United States)

    Mihalec, Marko; Slavič, Janko; Boltežar, Miha

    2016-12-01

    Synchrosqueezing is a procedure for improving the frequency localization of a continuous wavelet transform. This research focuses on using a synchrosqueezed wavelet transform (SWT) to determine the damping ratios of a vibrating system using a free-response signal. While synchrosqueezing is advantageous due to its localisation in the frequency, damping identification with the original SWT is not sufficiently accurate. Here, the synchrosqueezing was researched in detail, and it was found that an error in the frequency occurs as a result of the numerical calculation of the preliminary frequencies. If this error were to be compensated, a better damping identification would be expected. To minimize the frequency-shift error, three different strategies are investigated: the scale-dependent coefficient method, the shifted-coefficient method and the autocorrelated-frequency method. Furthermore, to improve the SWT, two synchrosqueezing criteria are introduced: the average SWT and the proportional SWT. Finally, the proposed modifications are tested against close modes and the noise in the signals. It was numerically and experimentally confirmed that the SWT with the proportional criterion offers better frequency localization and performs better than the continuous wavelet transform when tested against noisy signals.

  9. Unified systolic array for fast computation of the discrete cosine transform, discrete sine transform, and discrete Hartley transform

    Science.gov (United States)

    Pan, Sung B.; Park, Rae-Hong

    1997-12-01

    A two-dimensional (2-D) very large scale integration (VLSI) architecture using a unified systolic array for fast computation of the discrete cosine transform (DCT), the discrete sine transform (DST), and the discrete Hartley transform (DHT) is proposed. The N-point discrete transform is decomposed into even- and odd-numbered frequency samples and they are computed independently at the same time. The proposed unified systolic array architecture can compute the DCT, the DST, and the DHT by defining different coefficient values specific for each transform. We also present another architecture for computation of the DHT, a modified version of the unified systolic array structure, which is faster than the unified architecture by a factor of 2. In addition, the proposed unified architecture can be employed for computation of the inverse DCT (IDCT), the inverse DST (IDST), and the inverse DHT (IDHT) with some modifications.

  10. Instantaneous Frequency Attribute Comparison

    Science.gov (United States)

    Yedlin, M. J.; Margrave, G. F.; Ben Horin, Y.

    2013-12-01

    The instantaneous seismic data attribute provides a different means of seismic interpretation, for all types of seismic data. It first came to the fore in exploration seismology in the classic paper of Taner et al (1979), entitled " Complex seismic trace analysis". Subsequently a vast literature has been accumulated on the subject, which has been given an excellent review by Barnes (1992). In this research we will compare two different methods of computation of the instantaneous frequency. The first method is based on the original idea of Taner et al (1979) and utilizes the derivative of the instantaneous phase of the analytic signal. The second method is based on the computation of the power centroid of the time-frequency spectrum, obtained using either the Gabor Transform as computed by Margrave et al (2011) or the Stockwell Transform as described by Stockwell et al (1996). We will apply both methods to exploration seismic data and the DPRK events recorded in 2006 and 2013. In applying the classical analytic signal technique, which is known to be unstable, due to the division of the square of the envelope, we will incorporate the stabilization and smoothing method proposed in the two paper of Fomel (2007). This method employs linear inverse theory regularization coupled with the application of an appropriate data smoother. The centroid method application is straightforward and is based on the very complete theoretical analysis provided in elegant fashion by Cohen (1995). While the results of the two methods are very similar, noticeable differences are seen at the data edges. This is most likely due to the edge effects of the smoothing operator in the Fomel method, which is more computationally intensive, when an optimal search of the regularization parameter is done. An advantage of the centroid method is the intrinsic smoothing of the data, which is inherent in the sliding window application used in all Short-Time Fourier Transform methods. The Fomel technique

  11. On the use of Stockwell transform in structural dynamic analysis

    Indian Academy of Sciences (India)

    H Serdar Kuyuk

    2015-02-01

    Time-frequency analysis of earthquake records using Fourier transform is a fundamental, reliable and useful tool in earthquake engineering and engineering seismology. It will be however no longer functional if the frequency variation is analysed in time domain. Short time Fourier transform is utilized for the same purpose but this has also its own limitations and restrictions. In this research, Stockwell transform (S-transform), is evaluated in investigating frequency content of signal in time domain. First, the effectiveness of S-transform was tested by a non-stationary synthetic signal series with a sum of various instantaneous time varying frequency functions. Then, transform was employed to three different earthquake waveforms of Iwate-Miyagi Nairiku earthquake (Mw 6.9, 2008); recorded in near, moderate and far sites. Finally, an application was demonstrated for determining dynamic response of three-story frame structure by using El Centro earthquake compiled with harmonic motion. Unlike widely used continuous wavelet transform, which provides temporal and spectral information simultaneously, S-transform is very straightforward and easy to manipulate for interpretations. All cases considered in this research showed that Stransform can be implemented for further research activities related with frequencydependent strong motion analysis by practitioners and engineers. S-transform can distinguish abrupt frequency changes in structures effectively and accurately.

  12. Transformations of emotional experience.

    Science.gov (United States)

    de Cortiñas, Lia Pistiner

    2013-06-01

    personality's attitude towards mental pain. The differentiation between psychotic, neurotic or autistic functioning depends on what defences are erected to avoid mental pain. The primary link between infant and mother is where the building of mental equipment takes place, through communicational forms that, to begin with, are not verbal. The author suggests the need for the development of an ideo-grammar (in gestures, paralinguistic forms, etc.) in primary relations, as the precursor forms that will become the matrix for the mental tools for dealing with emotional experiences in a mature way. The paper stresses the significance of the parental containing function for the development of symbolization of prenatal emotional experiences. This containment develops ideograms, transformations of sense impressions into proto-symbols, instruments that attenuate the traumatic experiences of helplessness. The author takes Bion's ideas about extending the notion of dream-work to an alpha function that goes on continually, day and night, transforming raw emotional experiences in a 'dream'. In order to acquire a meaning, facts need to be 'dreamed' in this extended sense. Meaning and truth are the nurture of the mind. Mental growth, the development of adequate tools--including reverie--for dealing with mental pain, seen from a psychoanalytic perspective including reverie, implies that the object becomes a provider of meanings. Analysis begins to aim primarily at the generation or expansion of the mental container, instead of predominantly working on unconscious contents as such.

  13. 基于改进小波系数奇异值分解和小波去噪的低频振荡时变模式辨识%A Method to Identify Time-Varying Mode of Low Frequency Oscillation by Continuous Wavelet Transform Based on Raising Singular Value Decomposition of Wavelet Coefficient and Wavelet Denoising

    Institute of Scientific and Technical Information of China (English)

    栾某德; 刘涤尘; 廖清芬; 董超; 欧阳利平

    2012-01-01

    Based on the combination of continuous wavelet transform (CWT) with singular value decomposition (SVD), a new algorithm to identify oscillation frequency of signal, extract mode information and denoise signal by raising SVD of wavelet coefficient is proposed. The condition that under high noise level or closely spaced mode of noise, the wavelet ridges are unsharp and even the frequency is hard to extract due to the aliasing and intersection of wavelet ridges can be overcome by the proposed method, and the frequencies of oscillation modes in different orders can be identified according to frequency vectors of the raised SVD of wavelet coefficients. Meanwhile the wavelet energy coefficient is chosen to identify the dominant oscillation mode, and signal denoising is performed by use of wavelet soft-thresholding denoising and restructured matrix after the SVD of wavelet coefficient. CWT can be used to deal with time-varying low-frequency oscillation signals containing time-varying oscillation mode, and the identification accuracy of mode parameters is high. Both effectiveness and applicability of the proposed algorithm are verified by simulation results.%提出了一种基于连续小波变换(continuouswalelettranSform,CwT)和奇异值分解(Singularvaluedecomposition,SVD)相结合的提升小波系数SVD辨识信号振荡频率和模式信息提取及信号去噪的新方法。克服了噪声较大或者密集模态时,小波脊线不清晰甚至会出现混叠和交叉难以提取频率的情况,根据提升的小波系数奇异值分解频率向量识别各阶振荡模式的频率。同时选用小波能量系数来识别主导振荡模式,用小波软阈值去噪和SVD分解后矩阵重构来进行信号去噪。CWT可以处理含时变振荡模式的低频振荡信号,且对模式参数具有较高的辨识精度。仿真算例验证了算法的有效性和适用性。

  14. 基于频率切片小波变换和支持向量机的癫痫脑电信号自动检测∗%Automatic seizure detection of electro encephalogram signals based on frequency slice wavelet transform and supp ort vector machine

    Institute of Scientific and Technical Information of China (English)

    张涛; 陈万忠; 李明阳

    2016-01-01

    实现癫痫脑电信号的自动检测对癫痫的临床诊断和治疗具有重要意义.本文提出先使用频率切片小波变换分离出5个不同频段的节律信号,再分别计算每个节律信号的近似熵和相邻节律的波动指数,最后使用遗传算法优化的支持向量机进行分类.实验结果表明,所提出的方法能够对正常、癫痫发作间期和癫痫发作期三种脑电信号进行准确分类,分类准确率为98.33%.%Over 50 million people all over the world are suffering from epilepsy. It is of great significance to achieve automatic seizure detection in electroencephalogram (EEG) signal for clinical diagnosis and treatment. In order to achieve automatic diagnosis of epilepsy, a multitude of automated computer aided diagnostic techniques have been proposed. However, only a few of studies lay emphasis on the effects of different rhythm signals. To explore the influence of rhythm signals on classification accuracy, a newly-developed time-frequency analysis method called frequency slice wavelet transform (FSWT), which is able to locate arbitrary time-frequency range with the use of frequency slice function and whose inverse transformation only relies on fast Fourier transform, is employed to extract five different rhythm signals, namelyδ (0.5–4 Hz), θ (4–8 Hz), α (8–13 Hz), β (13–30 Hz) and γ (30–50 Hz) from original EEG signal. Subsequently, for extracting the nonlinear and linear features, the approximate entropy of each rhythm signal and fluctuation index of adjacent rhythm signals are calculated to reflect the variation characteristics of rhythm signals and they are flocked together to form the nine-dimensional feature vectors. Finally, the extracted vectors are fed into a support vector machine (SVM) which is optimized by genetic algorithms (GA) for classification. Specifically, since the parameters of SVM are associated with the final classification accuracy and appropriate parameters could

  15. Speech Compression Using Multecirculerletet Transform

    Directory of Open Access Journals (Sweden)

    Sulaiman Murtadha

    2012-01-01

    Full Text Available Compressing the speech reduces the data storage requirements, leading to reducing the time of transmitting the digitized speech over long-haul links like internet. To obtain best performance in speech compression, wavelet transforms require filters that combine a number of desirable properties, such as orthogonality and symmetry.The MCT bases functions are derived from GHM bases function using 2D linear convolution .The fast computation algorithm methods introduced here added desirable features to the current transform. We further assess the performance of the MCT in speech compression application. This paper discusses the effect of using DWT and MCT (one and two dimension on speech compression. DWT and MCT performances in terms of compression ratio (CR, mean square error (MSE and peak signal to noise ratio (PSNR are assessed. Computer simulation results indicate that the two dimensions MCT offer a better compression ratio, MSE and PSNR than DWT.

  16. Embedded Solenoid Transformer for Power Conversion

    DEFF Research Database (Denmark)

    2015-01-01

    A resonant power converter for operation in the radio frequency range, preferably in the VHF, comprises at least one PCB-embedded transformer. The transformer is configured for radio frequency operation and comprises a printed circuit board defining a horizontal plane, the printed circuit board...... and second embedded solenoids are formed in the conductive layers of the printed circuit board, wherein each full turn of an embedded solenoid has a horizontal top portion formed in an upper conductive layer, a horizontal bottom portion formed in a lower conductive layer, and two vertical side portions...

  17. Reciprocal link for a coupled Camassa-Holm type equation

    Science.gov (United States)

    Li, Nianhua; Zhang, Jinshun; Wu, Lihua

    2016-04-01

    A coupled Camassa-Holm type equation is linked to the first negative flow in a modified Drinfeld-Sokolov III hierarchy by a transformation of reciprocal type. Meanwhile the Lax pair and bi-Hamiltonian structure behaviors of this coupled Camassa-Holm type equation under the reciprocal transformation are analyzed.

  18. Modelling the pulse transformer in SPICE

    Science.gov (United States)

    Godlewska, Malgorzata; Górecki, Krzysztof; Górski, Krzysztof

    2016-01-01

    The paper is devoted to modelling pulse transformers in SPICE. It shows the character of the selected models of this element, points out their advantages and disadvantages, and presents the results of experimental verification of the considered models. These models are characterized by varying degrees of complexity - from linearly coupled linear coils to nonlinear electrothermal models. The study was conducted for transformer with ring cores made of a variety of ferromagnetic materials, while exciting the sinusoidal signal of a frequency 100 kHz and different values of load resistance. The transformers operating conditions under which the considered models ensure the acceptable accuracy of calculations are indicated.

  19. Electronic Voltage and Current Transformers Testing Device

    Directory of Open Access Journals (Sweden)

    Yong Xiao

    2012-01-01

    Full Text Available A method for testing electronic instrument transformers is described, including electronic voltage and current transformers (EVTs, ECTs with both analog and digital outputs. A testing device prototype is developed. It is based on digital signal processing of the signals that are measured at the secondary outputs of the tested transformer and the reference transformer when the same excitation signal is fed to their primaries. The test that estimates the performance of the prototype has been carried out at the National Centre for High Voltage Measurement and the prototype is approved for testing transformers with precision class up to 0.2 at the industrial frequency (50 Hz or 60 Hz. The device is suitable for on-site testing due to its high accuracy, simple structure and low-cost hardware.

  20. Genetic Transformation System for the Fungal Soybean Pathogen Cercospora kikuchii.

    Science.gov (United States)

    Upchurch, R G; Ehrenshaft, M; Walker, D C; Sanders, L A

    1991-10-01

    An altered beta-tubulin gene that confers resistance to the fungicide benomyl was isolated from a genomic library of a UV-induced mutant of Cercospora kikuchii and used as a selectable marker for transformation. The level of benomyl resistance conferred to the transformants was at least 150-fold greater than the intrinsic resistance of the C. kikuchii recipient protoplasts. In the majority of cases, the tubulin fragment was integrated at the native beta-tubulin locus, apparently by gene replacement or gene conversion. The frequency of transformation ranged from 0.2 to 6 transformants per mug of DNA, depending on the recipient strain. Transformation with linearized plasmid resulted in a higher frequency, without changing the type of integration event. Transformants were phenotypically stable after eight consecutive transfers on medium without benomyl. This is the first report of a genetic transformation system for a Cercospora species.