WorldWideScience

Sample records for balanced heterodyne detection

  1. Ultra-Low Mean-Photon-Number Measurement with Balanced Optical Heterodyne Detection

    Institute of Scientific and Technical Information of China (English)

    李刚; 李利平; 杜志静; 刘涛; 张天才; 王军民

    2004-01-01

    Determination of an ultra-low mean photon number is an important issue, either for precise optical measurement or understanding the interaction between individual atoms and photons inside an optical cavity. By utilizing a homemade balanced optical heterodyne detection system, the cw minimum measurable power of 3.6 fW has been reached, whereas the minimum mean photon number of = 0.0014 in our micro-cavity with finesse of 2 × 105and optical length of 48 μm can be realized.

  2. Heterodyne pump-probe and four-wave mixing in semiconductor optical amplifiers using balanced lock-in detection

    DEFF Research Database (Denmark)

    Borri, Paola; Langbein, Wolfgang; Mørk, Jesper;

    1999-01-01

    We demonstrate a new detection scheme for pump-probe and four-wave mixing heterodyne experiments, using balanced detection and a dual-phase lock-in for spectral filtering. The technique allows the use of low repetition-rate laser systems, as is demonstrated on an InGaAsP/InP bulk optical amplifier...... at 1.53 mym. Ultrafast pump-induced changes in the amplitude and phase of the transmitted probe signal are simultaneously measured, going from small to large signal changes and with no need of an absolute phase calibration, showing the versatility and the sensitivity of this detection scheme. The...... results for small perturbations are consistent with previous pump-probe experiments reported in literature. Time-resolved four-wave mixing in the absorption regime of the device is measured, and compared with numerical simulations, indicating a 100 fs dephasing time....

  3. Experimental demonstration of coherent OCDMA using heterodyne detection.

    Science.gov (United States)

    Yang, Yi; Petrillo, Keith G; Ting, Hong-Fu; Khurgin, Jacob B; Cooper, A Brinton; Foster, Mark A

    2013-07-01

    We present the first experimental demonstration of a practical, fully coherent, optical code division multiple access (OCDMA) scheme that can fully suppress multiple access interference (MAI) and speckle noise without phase locking or thresholding and gating. The scheme is sourced from an optical comb generator and uses spectral phase encoding and a heterodyne receiver with balanced detection. Here we present results for a four-user configuration at 50% load. At 4.5 Gbits/s per user, the system achieves a signal to MAI ratio of 648 at a bit error rate of 10(-7). PMID:23811925

  4. Experimental Study of Quantum Noise in Optical Heterodyne Detection

    OpenAIRE

    He, Dechao; Xie, Boya; XIAO, Yu; Feng, Sheng

    2013-01-01

    We experimentally investigate the quantum-noise performance of a conventional heterodyne detector and find significant discrepancy between experiment and theory. Further investigations are highly recommended for deeper insight into the physics related to the quantum noise in optical heterodyne detection.

  5. Spatial Heterodyne Spectrometer for Aviation Hazard Detection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Physical Sciences Inc (PSI) proposes the development of a longwave infrared (LWIR) imaging spatial heterodyne spectrometer (I-SHS) for standoff detection of clear...

  6. Nonlinear nanochannels for room temperature terahertz heterodyne detection

    International Nuclear Information System (INIS)

    The potentialities of AlGaN/GaN nanochannels with broken symmetry (also called self-switching diodes) as direct and heterodyne THz detectors are analyzed. The operation of the devices in the free space heterodyne detection scheme have been measured at room temperature with RF up to 0.32 THz and explained as a result of high-frequency nonlinearities using Monte Carlo simulations. Intermediate-frequency bandwidth of 40 GHz is obtained. (paper)

  7. Heterodyne detection with mismatch correction base on array detector

    Science.gov (United States)

    Hongzhou, Dong; Guoqiang, Li; Ruofu, Yang; Chunping, Yang; Mingwu, Ao

    2016-07-01

    Based on an array detector, a new heterodyne detection system, which can correct the mismatches of amplitude and phase between signal and local oscillation (LO) beams, is presented in this paper. In the light of the fact that, for a heterodyne signal, there is a certain phase difference between the adjacent two samples of analog-to-digital converter (ADC), we propose to correct the spatial phase mismatch by use of the time-domain phase difference. The corrections can be realized by shifting the output sequences acquired from the detector elements in the array, and the steps of the shifting depend on the quantity of spatial phase mismatch. Numerical calculations of heterodyne efficiency are conducted to confirm the excellent performance of our system. Being different from previous works, our system needs not extra optical devices, so it provides probably an effective means to ease the problem resulted from the mismatches.

  8. Heterodyne detection with mismatch correction based on array detector

    Science.gov (United States)

    Dong, Hongzhou; Li, Guoqiang; Yang, Ruofu; Yang, Chunping; Ao, Mingwu

    2016-07-01

    Based on an array detector, a new heterodyne detection system, which can correct the mismatches of amplitude and phase between signal and local oscillation (LO) beams, is presented in this paper. In the light of the fact that, for a heterodyne signal, there is a certain phase difference between the adjacent two samples of analog-to-digital converter (ADC), we propose to correct the spatial phase mismatch by use of the time-domain phase difference. The corrections can be realized by shifting the output sequences acquired from the detector elements in the array, and the steps of the shifting depend on the quantity of spatial phase mismatch. Numerical calculations of heterodyne efficiency are conducted to confirm the excellent performance of our system. Being different from previous works, our system needs not extra optical devices, so it provides probably an effective means to ease the problem resulted from the mismatches.

  9. Towards magnetic resonance in scanning tunneling microscopy using heterodyne detection

    OpenAIRE

    Peter, Moritz

    2015-01-01

    The present work introduces a new concept for magnetic resonance measurements in the GHz regime inside a scanning tunneling microscope. It is based on heterodyne detection in a spin-polarized tunneling barrier. The experimental requirements, including a new method to suppress transmission effects, are explained. Measurements on three model systems which were studied to validate the new technique are presented and compared to simulations.

  10. Atom interferometric gravitational wave detection using heterodyne laser links

    CERN Document Server

    Hogan, Jason M

    2015-01-01

    We propose a scheme based on a heterodyne laser link that allows for long baseline gravitational wave detection using atom interferometry. While the baseline length in previous atom-based proposals is constrained by the need for a reference laser to remain collimated as it propagates between two satellites, here we circumvent this requirement by employing a strong local oscillator laser near each atom ensemble that is phase locked to the reference laser beam. Longer baselines offer a number of potential advantages, including enhanced sensitivity, simplified atom optics, and reduced atomic source flux requirements.

  11. The performance of heterodyne detection system for partially coherent beams in turbulent atmosphere

    Science.gov (United States)

    Chengqiang, Li; Tingfeng, Wang; Heyong, Zhang; Jingjiang, Xie; Lisheng, Liu; Shuai, Zhao; Jin, Guo

    2015-12-01

    The performance of heterodyne system is discussed for partially coherent beams in turbulent atmosphere by introducing turbulence spectrum of refractive-index fluctuations. Several analytic formulae for the heterodyne detection system using the partially coherent Gaussian Schell-model beam are presented. Based on Tatarskii spectrum model, some numerical results are given for the variation in the heterodyne efficiency with the misalignment angle, detector diameter, turbulence conditions, and parameters of the overlapping beams. According to the numerical results, we find that the turbulent atmosphere degrades the heterodyne efficiency significantly, and the variation in heterodyne efficiency is even slower against the misalignment angle in turbulence. For the deterministic received signal and the detector, the performance of the heterodyne detection can be adjusted by controlling the local oscillator signal parameters.

  12. Terahertz balanced self-heterodyne spectrometer with SNR-limited phase-measurement sensitivity.

    Science.gov (United States)

    Hisatake, Shintaro; Koda, Yuki; Nakamura, Ryosuke; Hamada, Norio; Nagatsuma, Tadao

    2015-10-01

    Photonics-based frequency-domain terahertz (THz) wave measurement systems have received significant attention in both scientific and industrial fields due to their high-frequency resolution. Highly sensitive phase-measurement systems have been desired in the chemical, material, and biomedical sciences to facilitate microanalysis of materials. Here, we demonstrate a balanced self-heterodyne technique that, for the first time, simultaneously offers wide frequency tunability of more than 2.5 THz and high phase sensitivity, which is limited only by the signal-to-noise ratio (SNR) of the amplitude measurement. Using free-running lasers for THz wave generation and detection, the experimentally achieved minimum detectable optical path length change was 400±50 nm at 2 THz for a SNR of 37.7 ± 0.7 dB, even though the theoretically expected SNR-limited value was 310 ± 20 nm. The phase measurement sensitivity of our system is almost one order of magnitude better than that of the conventional systems in which limitations arise from phase instabilities in the optical components and/or laser linewidth. PMID:26480182

  13. Heterodyne Detection of Gravitational Waves in a Michelson Interferometer with a Vibrating Mirror

    OpenAIRE

    Ben-Aryeh, Y.

    1999-01-01

    A new heterodyne detection method is suggested for detecting gravitational waves in a Michelson Interferometer. The method is based on interference between phase changes which are induced by a vibrating mirror with phase changes which are due to the gravitational waves. The advantage of using a second order correlation function in the present analysis is discussed.

  14. A new thermal radiation detector using optical heterodyne detection of absorbed energy

    Science.gov (United States)

    Davis, C. C.; Petuchowski, S. J.

    1983-01-01

    The operating principles of a new kind of room-temperature thermal radiation detector are described. In this device modulated light heats a gas, either directly or by conduction from a thin absorbing membrane, and the resultant change in density of the gas is detected by optical heterodyning. The performance of a membrane device of this kind agrees well with the predictions of theory.

  15. Application of FIR heterodyne detection to collective scattering measurements of tokamak microturbulence

    International Nuclear Information System (INIS)

    Multichannel collective scattering of far-infrared (FIR) laser radiation is employed on the TEXT tokamak to investigate small-scale turbulent density fluctuations. A twin-frequency optically pumped FIR laser operating at 1222 μm (≅20 mW) and a difference frequency Δω/sub IF//2π≅1 MHz is used for the source and local oscillator beams. This permits heterodyne detection of the frequency-shifted scattered radiation which is necessary to determine wave propagation direction of plasma density fluctuations. The need for heterodyne versus homodyne detection is demonstrated. Such a diagnostic capability has allowed preliminary identification of the ion pressure-gradient-driven instability (whose most notable signature is that of turbulent fluctuations propagating in the ion diamagnetic drift direction) which is potentially responsible for saturation of the global energy confinement time with increasing density in tokamak plasmas

  16. Study of optical nonlinearity of a highly dispersive medium using optical heterodyne detection technique

    CERN Document Server

    Bhowmick, Arup; Mohapatra, Ashok K

    2016-01-01

    We discuss the optical heterodyne detection technique to study the absorption and dispersion of a probe beam propagating through a medium with a narrow resonance. The technique has been demonstrated for Rydberg Electro-magnetically induced transparency (EIT) in rubidium thermal vapor and the optical non-linearity of a probe beam with variable intensity has been studied. A quantitative comparison of the experimental result with a suitable theoretical model is presented. The limitations and the working regime of the technique are discussed.

  17. Simultaneous Unbalanced Shared Local Oscillator Heterodyne Interferometry (SUSHI) for high SNR, minimally destructive dispersive detection of time-dependent atomic spins

    CERN Document Server

    Locke, Mary

    2013-01-01

    We demonstrate "Simultaneous Unbalanced Shared Local Oscillator Heterodyne Interferometry (SUSHI)," a new method for minimally destructive, high SNR dispersive detection of atomic spins. In SUSHI a dual-frequency probe laser interacts with atoms in one arm of a Mach-Zehnder interferometer, then beats against a bright local oscillator beam traversing the other arm, resulting in two simultaneous, independent heterodyne measurements of the atom-induced phase shift. Measurement noise due to mechanical disturbances of beam paths is strongly rejected by the technique of \\emph{active subtraction} in which anti-noise is actively written onto the local oscillator beam via an optical phase-locked-loop. In SUSHI, technical noise due to phase, amplitude, and frequency fluctuations of the various laser fields is strongly rejected (i) for any mean phase bias between the interferometer arms, (ii) without the use of piezo actuated mirrors, and (iii) without signal balancing. We experimentally demonstrate an ultra-low technic...

  18. Heterodyne detection of ruby laser light scattered in a theta pinch plasma

    International Nuclear Information System (INIS)

    Ruby laser light scattered by a 1016 cm-3, 5 eV deuterium theta pinch plasma is detected and its frequency and wavelength spectra measured by heterodyne techniques using a vacuum photodiode as a mixer, stray light radiation as the local oscillator and a UHF communications receiver as a frequency analyser. Scattered light comes predominantly from k vectors parallel to the magnetic field. Frequency and wavelength distributions showed maxima at 680 MHz and 4 x 10-3 respectively, consistent with scattering by an ion acoustic wave corresponding to plasma temperature 8 eV. The temperature deduced from the plasma diamagnetism is 4.8 eV. (author)

  19. Multifunctional fiber-optic microwave links based on remote heterodyne detection

    DEFF Research Database (Denmark)

    Gliese, Ulrik Bo; Nielsen, Torben Nørskov; Nielsen, Søren Nørskov;

    1998-01-01

    fiber-optic microwave links. The resulting links are inherently transparent. As opposed to DD links, RHD links can perform radio-system functionalities such as modulation and frequency conversion in addition to transparency. All of these three functionalities are presented and experimentally...... carrier to a 9-GHz carrier with penalty-free transmission over 25 km of optical fiber. Finally, the transparent link transmits a standard FM video 7.6-GHz radio-link signal over 25 km of optical fiber without measurable distortion......The multifunctionality of microwave links based on remote heterodyne detection (RHD) of signals from a dual-frequency laser transmitter is discussed and experimentally demonstrated in this paper. Typically, direct detection (DD) in conjunction with optical intensity modulation is used to implement...

  20. Multichannel optical-fibre heterodyne interferometer for ultrasound detection of partial discharges in power transformers

    International Nuclear Information System (INIS)

    A multichannel interferometric system is proposed for the ultrasonic detection of partial discharges using intrinsic optical fibre sensors that may be immersed in oil. It is based on a heterodyne scheme which drives at least four sensor heads in order to localize the source of the acoustic emissions. Proper design of the sensing head improves its sensitivity through magnification and reaches a compact encapsulated probe able to be installed within power transformers. The optoelectronic implementation and the experimental tests are presented to optimize the resolution (4 channels—4 mrad). In addition, the results of ultrasound measurements at 150 kHz with an optical fibre sensor immersed in water in an acoustic test bench are shown, in which a resolution better than 10 Pa was obtained. Finally, the set-up for three-phase power transformers is demonstrated and characterized to detect and locate the source of acoustic emissions. (paper)

  1. Two-Dimensional Heterodyne-Detected VSFG Spectroscopy of Water Molecules at Charged Interfaces

    Directory of Open Access Journals (Sweden)

    Yamaguchi S.

    2013-03-01

    Full Text Available Two-dimensional heterodyne-detected vibrational sum-frequency generation (2D-HD-VSFG spectroscopy of water at interfaces has been realized for the first time. In the present study, 2D-HD-VSFG spectra were measured at a charged monolayer / isotopically diluted water interface. In contrast to the 2D-IR spectrum of bulk isotopically diluted water, the 2D-HD- VSFG of the charged interface shows a narrower bleach band in the higher frequency region immediately after the photoexcitation. The results clearly show that the dynamics of the water at the charged interface is different from that in the bulk, reflecting the different environment where water molecules are located.

  2. Attometer resolution spectral analysis based on polarization pulling assisted Brillouin scattering merged with heterodyne detection.

    Science.gov (United States)

    Preussler, Stefan; Schneider, Thomas

    2015-10-01

    Spectral analysis is essential for measuring and monitoring advanced optical communication systems and the characterization of active and passive devices like amplifiers, filters and especially frequency combs. Conventional devices have a limited resolution or tuning range. Therefore, the true spectral shape of the signal remains hidden. In this work, a small part of the signal under test is preselected with help of the polarization pulling effect of stimulated Brillouin scattering where all unwanted spectral components are suppressed. Subsequently, this part is analyzed more deeply through heterodyne detection. Thereby, the local oscillator is generated from a narrow linewidth fiber laser which acts also as pump wave for Brillouin scattering. By scanning the pump wave together with the local oscillator through the signal spectrum, the whole signal is measured. The method is tunable over a broad wavelength range, is not affected by unwanted mixing products and utilizes a conventional narrow bandwidth photo diode. First proof of concept experiments show the measurement of the power spectral density function with a resolution in the attometer or lower kilohertz range at 1550 nm. PMID:26480198

  3. Heterodyne detection and transmission of 60-Gbaud PDM-QPSK signal with SE of 4b/s/Hz.

    Science.gov (United States)

    Li, Xinying; Xiao, Jiangnan; Yu, Jianjun

    2014-04-21

    We experimentally demonstrate 8 × 240-Gb/s super-Nyquist wavelength-division-multiplexing (WDM) polarization-division-multiplexing quadrature-phase-shift-keying (PDM-QPSK) signal transmission on a 50-GHz grid with a net spectral efficiency (SE) of 4b/s/Hz adopting hardware-efficient simplified heterodyne detection. 9-ary quadrature-amplitude-modulation-like (9QAM-like) processing based on multi-modulus blind equalization (MMBE) is adopted to reduce analog-to-digital converter (ADC) bandwidth requirement and improve receiver sensitivity. The transmission distance at the soft-decision forward-error-correction (SD-FEC) threshold of 2 × 10(-2) is 2 × 420 km based on digital post filtering while largely extended to over 5 × 420 km based on 9QAM-like processing, which well illustrates 9QAM-like processing is more efficient for heterodyne coherent WDM system. Moreover, only two ADC channels are needed for simplified heterodyne detection of one 60-Gbaud PDM-QPSK WDM channel, and thus only one commercial oscilloscope (OSC) with two input ports can work well for each WDM channel. PMID:24787819

  4. Simultaneous Unbalanced Shared Local Oscillator Heterodyne Interferometry (SUSHI) for high SNR, minimally destructive dispersive detection of time-dependent atomic spins

    OpenAIRE

    Locke, Mary; Fertig, Chad

    2013-01-01

    We demonstrate "Simultaneous Unbalanced Shared Local Oscillator Heterodyne Interferometry (SUSHI)," a new method for minimally destructive, high SNR dispersive detection of atomic spins. In SUSHI a dual-frequency probe laser interacts with atoms in one arm of a Mach-Zehnder interferometer, then beats against a bright local oscillator beam traversing the other arm, resulting in two simultaneous, independent heterodyne measurements of the atom-induced phase shift. Measurement noise due to mecha...

  5. An experimental vital signs detection radar using low-IF heterodyne architecture and single-sideband transmission

    DEFF Research Database (Denmark)

    Jensen, Brian Sveistrup; Johansen, Tom Keinicke; Yan, Lei

    2013-01-01

    In this paper an experimental X-band radar system, called DTU-VISDAM, developed for the detection and monitoring of human vital signs is described. The DTU-VISDAM radar exploits a low intermediate frequency (IF) heterodyne RF front-end architecture and single-sideband (SSB) transmission for easier...... and more reliable extraction of the vital signs. The hardware implementation of the proposed low-IF RF front-end architecture and associated IF circuitry is discussed. Furthermore, the signal processing and calibration steps necessary to extract the vital signs information measured on a human subject...

  6. Far-field linear optical superresolution via heterodyne detection in a higher-order local oscillator mode

    CERN Document Server

    Yang, Fan; Moiseev, E S; Simon, Christoph; Lvovsky, A I

    2016-01-01

    The Rayleigh limit has so far applied to all microscopy techniques that rely on linear optical interaction and detection in the far field. Here we demonstrate that detecting the light emitted by an object in higher-order transverse electromagnetic modes (TEMs) can help achieving sub-Rayleigh precision for a variety of microscopy-related tasks. Using optical heterodyne detection in TEM01, we measure the position of coherently and incoherently emitting objects to within 0.0015 and 0.012 of the Rayleigh limit, respectively, and determine the distance between two incoherently emitting slits positioned within 0.28 of the Rayleigh limit with a precision of 0.019 of the Rayleigh limit. Extending our technique to higher-order TEMs enables full imaging with resolution significantly below the Rayleigh limit in a way that is reminiscent of quantum tomography of optical states.

  7. Potential of a Superconducting Photon Counter for Heterodyne Detection at Telecommunication Wavelength

    CERN Document Server

    Shcherbatenko, Mikhail; Semenov, Alexander; Kovalyuk, Vadim; Korneev, Alexander; Ozhegov, Roman; Kazakov, Alexander; Voronov, Boris M; Goltsman, Gregory N

    2016-01-01

    Here, we report on successful operation of a NbN thin film superconducting nanowire single-photon detector (SNSPD) in a coherent mode (as a mixer) at the telecommunication wavelength of 1550 nm. Providing the Local Oscillator power of the order of a few picowatts, we were practically able to reach the quantum noise limited sensitivity. The intermediate frequency gain bandwidth was limited by the spectral band of single-photon response pulse of the detector, which is proportional to the detector size. We observed gain bandwidth of 65 MHz and 140 MHz for 7x7 um^2 and 3x3 um^2 devices respectively. Tiny amount of the required Local Oscillator power and wide gain and noise bandwidths along with the needless of any Low Noise Amplification opens possibility for a photon counting heterodyne-born megapixel array development.

  8. Laser Heterodyning

    CERN Document Server

    Protopopov, Vladimir V

    2009-01-01

    Laser heterodyning is now a widespread optical technique, based on interference of two waves with slightly different frequencies within the sensitive area of a photo-detector. Its unique feature – preserving phase information about optical wave in the electrical signal of the photo-detector – finds numerous applications in various domains of applied optics and optoelectronics: in spectroscopy, polarimetry, radiometry, laser radars and Lidars, microscopy and other areas. The reader may be surprised by a variety of disciplines that this book covers and satisfied by detailed explanation of the phenomena. Very well illustrated, this book will be helpful for researches, postgraduates and students, working in applied optics.

  9. Theoretical study of the quantum noise in phase-sensitive heterodyne detection with a bichromatic local oscillator

    OpenAIRE

    Feng, Sheng; He, Dechao; Fan, Heng

    2015-01-01

    A traditional heterodyne detector, as a phase-insensitive device, suffers the well-known 3 dB noise penalty caused by image sideband vacuum. In contrast, a heterodyne detector with a bichromatic local oscillator, as a phase-sensitive device, should be exempted from the 3 dB noise penalty, in spite of the existence of the image sideband vacuum. Assuming coherent light at the input, we develop in this work a theory to describe the quantum nature of the phase-sensitive heterodyne detector, in a ...

  10. Optimal Signal Recovery for Pulsed Balanced Detection

    OpenAIRE

    de Icaza Astiz, Yannick A.; Lucivero, Vito Giovanni; León-Montiel, R. de J.; Mitchell, Morgan W.

    2014-01-01

    We demonstrate a new tool for filtering technical and electronic noises from pulses of light, especially relevant for signal processing methods in quantum optics experiments as a means to achieve the shot-noise level and reduce strong technical noise by means of a pattern function. We provide the theory of this pattern-function filtering based on balance detection. Moreover, we implement an experimental demonstration where 10 dB of technical noise is filtered after balance detection. Such fil...

  11. Bit-error-rate performance analysis of self-heterodyne detected radio-over-fiber links using phase and intensity modulation

    DEFF Research Database (Denmark)

    Yin, Xiaoli; Yu, Xianbin; Tafur Monroy, Idelfonso

    2010-01-01

    We theoretically and experimentally investigate the performance of two self-heterodyne detected radio-over-fiber (RoF) links employing phase modulation (PM) and quadrature biased intensity modulation (IM), in term of bit-error-rate (BER) and optical signal-to-noise-ratio (OSNR). In both links, self......-heterodyne receivers perform down-conversion of radio frequency (RF) subcarrier signal. A theoretical model including noise analysis is constructed to calculate the Q factor and estimate the BER performance. Furthermore, we experimentally validate our prediction in the theoretical modeling. Both the experimental and...... theoretical results show that the PM link offers superior OSNR receiver sensitivity performance (higher than 6 dB) over the quadrature biased IM counterpart....

  12. 双平衡式相干接收原理及其在外差干涉仪中的应用研究%Principle of Dual-balanced Coherent Receive and Its Application in Heterodyne Interferometer

    Institute of Scientific and Technical Information of China (English)

    庞亚军; 王春晖; 唐甜甜

    2012-01-01

    利用琼斯矩阵理论推导了光学双平衡式相干接收的原理,得到了具有正交相关性的包含全部光学信息的IQ信号,给出了基于IQ正交信号解调待测光信号信息的信号处理算法.基于该原理设计了一种高速微机电系统扫描式激光外差干涉仪,得到了待测玻璃的厚度信息分布图.该干涉仪的波前相位差提取准确度可高达0.01 rad、测量速度可达40 frame/s、最大测量直径可达到300mm,在实时光学检测方面有广阔的应用价值.%The principle of optical dual-balanced coherent receive is deduced using Jones matrix, the IQ signal is obtained that contains all the optical information,and the signal processing algorithm based on the IQ signal to demodulate optical signal information is given. Based on this principle, a high-speed MEMS scanning laser heterodyne interferometer is designed, and the thickness map of the test glass is obtained. The interferometer wavefront phase extraction accuracy achieves 0. 01 radians, the measurement speed reaches 40 frame/s, and the maximum measured diameter can reach 300 mm, which show the broad application value in real-time optical detection.

  13. Performance Analysis of Heterodyne-Detected OCDMA Systems Using PolSK Modulation over a Free-Space Optical Turbulence Channel

    Directory of Open Access Journals (Sweden)

    Fan Bai

    2015-10-01

    Full Text Available This paper presents a novel model of heterodyne-detected optical code-division multiple-access (OCDMA systems employing polarization shift keying (PolSK modulation over a free-space optical (FSO turbulence channel. In this article, a new transceiver configuration and detailed analytical model for the proposed system are provided and discussed, taking into consideration the potential of heterodyne detection on mitigating the impact of turbulence-induced irradiance fluctuation on the performance of the proposed system under the gamma-gamma turbulence channel. Furthermore, we derived the closed-form expressions for the system error probability and outage probability, respectively. We determine the advantages of the proposed modeling by performing a comparison with a direct detection scheme obtained from an evaluation of link performance under the same environment conditions. The presented work also shows the most significant impact factor that degrades the performance of the proposed system and indicates that the proposed approach offers an optimum link performance compared to conventional cases.

  14. Optimal signal recovery for pulsed balanced detection

    OpenAIRE

    Icaza Astiz, Yannik Alan de

    2015-01-01

    To measure quantum features in a classical world constrains us to extend the classical technology to the limit, inventing and discovering new schemes to use the classical devices, while reducing and filtering the sources of noise. Balanced detectors, e.g. when measuring a low- noise laser, have become an exceptional tool to attain the shot-noise level, i.e., the standard quantum limit for measuring light. To detect light pulses at this level requires to decreasing and also to filtering all ot...

  15. Experimental study of a phase-sensitive heterodyne detector

    OpenAIRE

    Fan, Heng; He, Dechao; Feng, Sheng

    2014-01-01

    It is believed that the quantum behaviors of homodyne detectors and traditional heterodyne detectors can be fully understood in the context of the quantum theory of optical detection. According to the theory, a 3 dB extra quantum noise has been predicted in a traditional heterodyne detector, as a phase-insensitive device, due to the existence of the image sideband vacuum. However, regarding the noise performance of a phase-sensitive heterodyne detector, a fundamental dilemma inevitably arises...

  16. Dual-signal heterodyne lock-in amplification with lasers

    NARCIS (Netherlands)

    Witteman, W.J.

    2006-01-01

    High-sensitivity heterodyne detection with lasers applied to radar and satellite communication is seriously hampered by the large electronic bandwidth due to Doppler shift and frequency instability. These drawbacks can be circumvented by dual-signal heterodyne detection. The system consists of mixin

  17. Six-wave mixing phase-dispersion by optical heterodyne detection in dressed reverse N-type four-level system

    Institute of Scientific and Technical Information of China (English)

    Gan Chen-Li; Nie Zhi-Qiang; Li Ling; Shen Lei-Jian; Zhang Yan-Peng; Song Jian-Ping; Li Yuan-Yuan; Zhang Xiang-Chen; Lu Ke-Qing

    2007-01-01

    We have investigated the dressed effects of non-degenerate four-wave mixing (NDFWM) and demonstrated a phase-sensitive method of studying the fifth-order nonlinear susceptibility due to atomic coherence in RN-type four-level system. In the presence of a strong coupling field, NDFWM spectrum exhibits Autler-Townes splitting, accompanied by either suppression or enhancement of the NDFWM signal, which is directly related to the competition between the absorption and dispersion contributions. The heterodyne-detected nonlinear absorption and dispersion of six-wave mixing signal in the RN-type system show that the hybrid radiation-matter detuning damping oscillation is in the THz range and can be controlled and modified through the colour-locked correlation of twin noisy fields.

  18. Study of Rydberg blockade mediated optical non-linearity in thermal vapor using optical heterodyne detection technique

    CERN Document Server

    Bhowmick, Arup; Mohapatra, Ashok K

    2016-01-01

    We demonstrate the phenomenon of blockade in two-photon excitations to the Rydberg state in thermal vapor. A technique based on optical heterodyne is used to measure the dispersion of a probe beam far off resonant to the D2 line of rubidium in the presence of a strong laser beam that couples to the Rydberg state via two-photon resonance. Density dependent suppression of the dispersion peak is observed while coupling to the Rydberg state with principal quantum number, n = 60. The experimental observation is explained using the phenomenon of Rydberg blockade. The blockade radius is measured to be about 2.2 {\\mu}m which is consistent with the scaling due to the Doppler width of 2-photon resonance in thermal vapor. Our result promises the realization of single photon source and strong single photon non-linearity based on Rydberg blockade in thermal vapor.

  19. Heterodyne detection at near-infrared wavelengths with a superconducting NbN hot-electron bolometer mixer.

    Science.gov (United States)

    Lobanov, Yury; Shcherbatenko, Michael; Shurakov, Alexander; Rodin, Alexander V; Klimchuk, Artem; Nadezhdinsky, Alexander I; Maslennikov, Sergey; Larionov, Pavel; Finkel, Matvey; Semenov, Alexander; Verevkin, Aleksandr A; Voronov, Boris M; Ponurovsky, Yakov; Klapwijk, Teunis M; Gol'tsman, Gregory N

    2014-03-15

    We report on the development of a highly sensitive optical receiver for heterodyne IR spectroscopy at the communication wavelength of 1.5 μm (200 THz) by use of a superconducting hot-electron bolometer. The results are important for the resolution of narrow spectral molecular lines in the near-IR range for the study of astronomical objects, as well as for quantum optical tomography and fiber-optic sensing. Receiver configuration as well as fiber-to-detector light coupling designs are discussed. Light absorption of the superconducting detectors was enhanced by nano-optical antennas, which were coupled to optical fibers. An intermediate frequency (IF) bandwidth of about 3 GHz was found in agreement with measurements at 300 GHz, and a noise figure of about 25 dB was obtained that was only 10 dB above the quantum limit. PMID:24690805

  20. 2D heterodyne-detected sum frequency generation study on the ultrafast vibrational dynamics of H{sub 2}O and HOD water at charged interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Ken-ichi; Singh, Prashant C. [Molecular Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Nihonyanagi, Satoshi; Tahara, Tahei, E-mail: tahei@riken.jp [Molecular Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Ultrafast Spectroscopy Research Team, RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Yamaguchi, Shoichi [Molecular Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Department of Applied Chemistry, Saitama University, 255 Shimo-Okubo, Saitama 338-8570 (Japan)

    2015-06-07

    Two-dimensional heterodyne-detected vibrational sum-frequency generation (2D HD-VSFG) spectroscopy is applied to study the ultrafast vibrational dynamics of water at positively charged aqueous interfaces, and 2D HD-VSFG spectra of cetyltrimethylammonium bromide (CTAB)/water interfaces in the whole hydrogen-bonded OH stretch region (3000 cm{sup −1} ≤ ω{sub pump} ≤ 3600 cm{sup −1}) are measured. 2D HD-VSFG spectrum of the CTAB/isotopically diluted water (HOD-D{sub 2}O) interface exhibits a diagonally elongated bleaching lobe immediately after excitation, which becomes round with a time constant of ∼0.3 ps due to spectral diffusion. In contrast, 2D HD-VSFG spectrum of the CTAB/H{sub 2}O interface at 0.0 ps clearly shows two diagonal peaks and their cross peaks in the bleaching region, corresponding to the double peaks observed at 3230 cm{sup −1} and 3420 cm{sup −1} in the steady-state HD-VSFG spectrum. Horizontal slices of the 2D spectrum show that the relative intensity of the two peaks of the bleaching at the CTAB/H{sub 2}O interface gradually change with the change of the pump frequency. We simulate the pump-frequency dependence of the bleaching feature using a model that takes account of the Fermi resonance and inhomogeneity of the OH stretch vibration, and the simulated spectra reproduce the essential features of the 2D HD-VSFG spectra of the CTAB/H{sub 2}O interface. The present study demonstrates that heterodyne detection of the time-resolved VSFG is critically important for studying the ultrafast dynamics of water interfaces and for unveiling the underlying mechanism.

  1. 2D heterodyne-detected sum frequency generation study on the ultrafast vibrational dynamics of H2O and HOD water at charged interfaces

    International Nuclear Information System (INIS)

    Two-dimensional heterodyne-detected vibrational sum-frequency generation (2D HD-VSFG) spectroscopy is applied to study the ultrafast vibrational dynamics of water at positively charged aqueous interfaces, and 2D HD-VSFG spectra of cetyltrimethylammonium bromide (CTAB)/water interfaces in the whole hydrogen-bonded OH stretch region (3000 cm−1 ≤ ωpump ≤ 3600 cm−1) are measured. 2D HD-VSFG spectrum of the CTAB/isotopically diluted water (HOD-D2O) interface exhibits a diagonally elongated bleaching lobe immediately after excitation, which becomes round with a time constant of ∼0.3 ps due to spectral diffusion. In contrast, 2D HD-VSFG spectrum of the CTAB/H2O interface at 0.0 ps clearly shows two diagonal peaks and their cross peaks in the bleaching region, corresponding to the double peaks observed at 3230 cm−1 and 3420 cm−1 in the steady-state HD-VSFG spectrum. Horizontal slices of the 2D spectrum show that the relative intensity of the two peaks of the bleaching at the CTAB/H2O interface gradually change with the change of the pump frequency. We simulate the pump-frequency dependence of the bleaching feature using a model that takes account of the Fermi resonance and inhomogeneity of the OH stretch vibration, and the simulated spectra reproduce the essential features of the 2D HD-VSFG spectra of the CTAB/H2O interface. The present study demonstrates that heterodyne detection of the time-resolved VSFG is critically important for studying the ultrafast dynamics of water interfaces and for unveiling the underlying mechanism

  2. Adaptive optics assisted Fourier domain OCT with balanced detection

    Science.gov (United States)

    Meadway, A.; Bradu, A.; Hathaway, M.; Van der Jeught, S.; Rosen, R. B.; Podoleanu, A. Gh.

    2011-03-01

    Two factors are of importance to optical coherence tomography (OCT), resolution and sensitivity. Adaptive optics improves the resolution of a system by correcting for aberrations causing distortions in the wave-front. Balanced detection has been used in time domain OCT systems by removing excess photon noise, however it has not been used in Fourier domain systems, as the cameras used in the spectrometers saturated before excess photon noise becomes a problem. Advances in camera technology mean that this is no longer the case and balanced detection can now be used to improve the signal to noise ratio in a Fourier domain (FD) OCT system. An FD-OCT system, enhanced with adaptive optics, is presented and is used to show the improvement that balanced detection can provide. The signal to noise ratios of single camera detection and balanced detection are assessed and in-vivo retinal images are acquired to demonstrate better image quality when using balance detection.

  3. Spectrally balanced detection for optical frequency domain imaging.

    Science.gov (United States)

    Chen, Yueli; de Bruin, Daniel M; Kerbage, Charles; de Boer, Johannes F

    2007-12-10

    In optical frequency domain imaging (OFDI) or swept-source optical coherence tomography, balanced detection is required to suppress relative intensity noise (RIN). A regular implementation of balanced detection by combining reference and sample arm signal in a 50/50 coupler and detecting the differential output with a balanced receiver is however, not perfect. Since the splitting ratio of the 50/50 coupler is wavelength dependent, RIN is not optimally canceled at the edges of the wavelength sweep. The splitting ratio has a nearly linear shift of 0.4% per nanometer. This brings as much as +/-12% deviation at the margins of wavelength-swept range centered at 1060nm. We demonstrate a RIN suppression of 33dB by spectrally corrected balanced detection, 11dB more that regular balanced detection. PMID:19550929

  4. Differential doppler heterodyning technique

    DEFF Research Database (Denmark)

    Lading, Lars

    1971-01-01

    Measuring velocity without disturbing the moving object is possible by use of the laser doppler heterodyning technique. Theoretical considerations on the doppler shift show that the antenna property of the photodetector can solve an apparent conflict between two different ways of calculating the...

  5. Laser heterodyne photothermal nondestructive method: extension to transparent probe

    Science.gov (United States)

    Pencheva, V.; Penchev, S.; Naboko, V.; Toyoda, K.; Donchev, T.

    2007-03-01

    We present a contribution to the development of the laser heterodyne method of nondestructive material analysis employing photothermal displacement (PTD) probe. PTD is a dominant factor of the photothermal effect in metals and semiconductors, where the derived linear dependence on absorbed energy exhibits a fingerprint of their physical properties. Theoretical consideration of the case of transparent probe is accomplished extending thermal diffusion model. Laser double heterodyne detection is verified for opaque and transparent probes, and in the exclusive case of silicon. The achieved resolution of photothermal displacement is less than 10 -12 m well above the limits of heterodyne measurement.

  6. Heterodyne Interferometer Angle Metrology

    Science.gov (United States)

    Hahn, Inseob; Weilert, Mark A.; Wang, Xu; Goullioud, Renaud

    2010-01-01

    A compact, high-resolution angle measurement instrument has been developed that is based on a heterodyne interferometer. The common-path heterodyne interferometer metrology is used to measure displacements of a reflective target surface. In the interferometer setup, an optical mask is used to sample the measurement laser beam reflecting back from a target surface. Angular rotations, around two orthogonal axes in a plane perpendicular to the measurement- beam propagation direction, are determined simultaneously from the relative displacement measurement of the target surface. The device is used in a tracking telescope system where pitch and yaw measurements of a flat mirror were simultaneously performed with a sensitivity of 0.1 nrad, per second, and a measuring range of 0.15 mrad at a working distance of an order of a meter. The nonlinearity of the device is also measured less than one percent over the measurement range.

  7. Linear frequency modulation multi-beam laser heterodyne measurement for the glass thickness

    Science.gov (United States)

    Yan-Chao, Li; Yi-Qiao, Wang; Chun-Yu, Liu; Jiu-Ru, Yang; Qun, Ding

    2016-02-01

    This paper uses the combination of laser heterodyne technology with linear frequency modulation technology to load thickness of plate glass to the heterodyne signal frequency. By researching on the theoretical models of heterodyne signal for measuring thickness of plate glass, the direct intensity detection can be replaced by heterodyne signal frequency detection and the effects of light source power stability and environmental perturbation can be removed. The measuring accuracy of electrostriction coefficient can be further improved by using the frequency demodulation to obtain thickness of plate glass. This method is used to measure the thickness of plate glass, and simulation results show that the maximum relative measurement error is 0.01 %.

  8. Parsimony, Exhaustivity and Balanced Detection in Neocortex.

    Science.gov (United States)

    Romagnoni, Alberto; Ribot, Jérôme; Bennequin, Daniel; Touboul, Jonathan

    2015-11-01

    The layout of sensory brain areas is thought to subtend perception. The principles shaping these architectures and their role in information processing are still poorly understood. We investigate mathematically and computationally the representation of orientation and spatial frequency in cat primary visual cortex. We prove that two natural principles, local exhaustivity and parsimony of representation, would constrain the orientation and spatial frequency maps to display a very specific pinwheel-dipole singularity. This is particularly interesting since recent experimental evidences show a dipolar structures of the spatial frequency map co-localized with pinwheels in cat. These structures have important properties on information processing capabilities. In particular, we show using a computational model of visual information processing that this architecture allows a trade-off in the local detection of orientation and spatial frequency, but this property occurs for spatial frequency selectivity sharper than reported in the literature. We validated this sharpening on high-resolution optical imaging experimental data. These results shed new light on the principles at play in the emergence of functional architecture of cortical maps, as well as their potential role in processing information. PMID:26587664

  9. Integrated Optical Heterodyne Interferometer in Lithium Niobate

    Science.gov (United States)

    Rubiyanto, A.; Herrmann, H.; Ricken, R.; Tian, F.; Sohler, W.

    A high performance integrated acousto-optical heterodyne interferometer has been developed for vibration measurement. All components including an acousto-optical TE-TM mode converters, two electro-optical TE-TM converters, two polarization splitters and two phase shifters are integrated on a X-cut Lithium Niobate substrate. The fully packaged optical integrated circuit (optical-IC) coupling with three fibers optics pigtails gave a signal-to-noise ratio of 69 dB with at 3 kHz bandwidth by using a commercial DFB laser diode as a light source with 1561 nm emission wavelength and a PIN-FET balanced receiver.

  10. Fast time-domain balanced homodyne detection of light

    Czech Academy of Sciences Publication Activity Database

    Haderka, Ondřej; Michálek, Václav; Urbášek, Vladimír; Ježek, M.

    2009-01-01

    Roč. 48, č. 15 (2009), 2884-2889. ISSN 0003-6935 R&D Projects: GA MŠk(CZ) 1M06002 Institutional research plan: CEZ:AV0Z10100522 Keywords : balanced homodyne detection * high-speed quantum-optical measurement * quantum cryptography Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.410, year: 2009

  11. Heterodyne effect in Hybrid CARS

    Science.gov (United States)

    Wang, Xi; Zhang, Aihua; Zhi, Miaochan; Sokolov, Alexei; Welch, George; Scully, Marlan

    2009-10-01

    We study the interaction between the resonant Raman signal and non-Raman field, either the concomitant nonresonant four-wave-mixing (FWM) background or an applied external field, in our recently developed scheme of coherent Anti-Stokes Raman scattering, a hybrid CARS. Our technique combines instantaneous coherent excitation of several characteristic molecular vibrations with subsequent probing of these vibrations by an optimally shaped, time-delayed, narrowband laser pulse. This pulse configuration mitigates the non-resonant FWM background while maximizing the Raman-resonant signal, and allows rapid and highly specific detection even in the presence of multiple scattering. We apply this method to non-invasive monitoring of blood glucose levels. Under certain conditions we find that the measured signal is linearly proportional to the glucose concentration due to optical interference with the residual background light, which allows reliable detection of spectral signatures down to medically-relevant glucose levels. We also study the interference between the CARS field and an external field (the local oscillator) by controlling their relative phase and amplitude. This control allows direct observation of the real and imaginary components of the third-order nonlinear susceptibility (χ^(3)) of the sample. We demonstrate that the heterodyne method can be used to amplify the signal and thus increase detection sensitivity.

  12. Detecting balancing selection in genomes: limits and prospects.

    Science.gov (United States)

    Fijarczyk, Anna; Babik, Wiesław

    2015-07-01

    In spite of the long-term interest in the process of balancing selection, its frequency in genomes and evolutionary significance remain unclear due to challenges related to its detection. Current statistical approaches based on patterns of variation observed in molecular data suffer from low power and a high incidence of false positives. This raises the question whether balancing selection is rare or is simply difficult to detect. We discuss genetic signatures produced by this mode of selection and review the current approaches used for their identification in genomes. Advantages and disadvantages of the available methods are presented, and areas where improvement is possible are identified. Increased specificity and reduced rate of false positives may be achieved by using a demographic model, applying combinations of tests, appropriate sampling scheme and taking into account intralocus variation in selection pressures. We emphasize novel solutions, recently developed model-based approaches and good practices that should be implemented in future studies looking for signals of balancing selection. We also draw attention of the readers to the results of recent theoretical studies, which suggest that balancing selection may be ubiquitous but transient, leaving few signatures detectable by existing methods. Testing this new theory may require the development of novel high-throughput methods extending beyond genomic scans. PMID:25943689

  13. Digitally Enhanced Heterodyne Interferometry

    Science.gov (United States)

    Shaddock, Daniel; Ware, Brent; Lay, Oliver; Dubovitsky, Serge

    2010-01-01

    Spurious interference limits the performance of many interferometric measurements. Digitally enhanced interferometry (DEI) improves measurement sensitivity by augmenting conventional heterodyne interferometry with pseudo-random noise (PRN) code phase modulation. DEI effectively changes the measurement problem from one of hardware (optics, electronics), which may deteriorate over time, to one of software (modulation, digital signal processing), which does not. DEI isolates interferometric signals based on their delay. Interferometric signals are effectively time-tagged by phase-modulating the laser source with a PRN code. DEI improves measurement sensitivity by exploiting the autocorrelation properties of the PRN to isolate only the signal of interest and reject spurious interference. The properties of the PRN code determine the degree of isolation.

  14. CCAT Heterodyne Instrument Development Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A key challenge in building a large pixel heterodyne array is efficiently and simultaneously delivering the astronomical signal and local oscillator power to each...

  15. Balanced homodyne detection in second-harmonic generation microscopy

    CERN Document Server

    Le Xuan, L; Brasselet, S; Perruchas, S; Tard, C; Gacoin, T; Xuan, Loc Le; Chauvat, Dominique; Brasselet, Sophie; Perruchas, Sandrine; Gacoin, Thierry

    2006-01-01

    We demonstrate the association of two-photon nonlinear microscopy with balanced homodyne detection for investigating second harmonic radiation properties at nanoscale dimensions. Variation of the relative phase between second-harmonic and fundamental beams is retrieved, as a function of the absolute orientation of the nonlinear emitters. Sensitivity down to approximately 3.2 photon/s in the spatio-temporal mode of the local oscillator is obtained. This value is high enough to efficiently detect the coherent second-harmonic emission from a single KTiOPO4 crystal of sub-wavelength size.

  16. Semiconductor optical amplifier-based heterodyning detection for resolving optical terahertz beat-tone signals from passively mode-locked semiconductor lasers

    International Nuclear Information System (INIS)

    An all-optical heterodyne approach based on a room-temperature controlled semiconductor optical amplifier (SOA) for measuring the frequency and linewidth of the terahertz beat-tone signal from a passively mode-locked laser is proposed. Under the injection of two external cavity lasers, the SOA acts as a local oscillator at their detuning frequency and also as an optical frequency mixer whose inputs are the self-modulated spectrum of the device under test and the two laser beams. Frequency and linewidth of the intermediate frequency signal (and therefore, the beat-tone signal) are resolved by using a photodiode and an electrical spectrum analyzer.

  17. Dove prism heterodyne refractometer

    Science.gov (United States)

    Hsu, Cheng-Chih; Lee, Chia-Yun; Chu, Kuan-Ho; Wu, Tsai-Chen

    2015-10-01

    In this study, we proposed an alternative method, integrating a Dove prism and precision circular heterodyne interferometry, for measuring the refractive index and concentration of sodium chloride and hydrogen peroxide solutions with low phase error. Due to the optical properties of the Dove prism, the test light undergoes total internal reflection (TIR) at the interface between the test sample and the prism. The light beam travels in and out of the Dove prism while maintaining the same direction. Therefore, only slight alignment is required, leading to only small errors in the phase and refractive index. In this study, the phase error, refractive index error, and resolution of the concentration are approximated to be 0.003°, 2×10-5, and 1×10-3 M, respectively. The proposed method has the advantages of a simple optical configuration, ease of operation, little alignment required, and high stability, and it allows for high-precision measurement of the refractive index and concentration of the liquid sample.

  18. Highspeed multiplexed heterodyne interferometry.

    Science.gov (United States)

    Isleif, Katharina-S; Gerberding, Oliver; Köhlenbeck, Sina; Sutton, Andrew; Sheard, Benjamin; Goßler, Stefan; Shaddock, Daniel; Heinzel, Gerhard; Danzmann, Karsten

    2014-10-01

    Digitally enhanced heterodyne interferometry is a metrology technique that uses pseudo-random noise codes for modulating the phase of the laser light. Multiple interferometric signals from the same beam path can thereby be isolated based on their propagation delay, allowing one to use advantageous optical layouts in comparison to classic laser interferometers. We present here a high speed version of this technique for measuring multiple targets spatially separated by only a few centimetres. This allows measurements of multiplexed signals using free beams, making the technique attractive for several applications requiring compact optical set-ups like for example space-based interferometers. In an experiment using a modulation and sampling rate of 1.25 GHz we are able to demonstrate multiplexing between targets only separated by 36 cm and we achieve a displacement measurement noise floor of <3 pm/√Hz at 10 Hz between them. We identify a limiting excess noise at low frequencies which is unique to this technique and is probably caused by the finite bandwidth in our measurement set-up. Utilising an active clock jitter correction scheme we are also able to reduce this noise in a null measurement configuration by one order of magnitude. PMID:25322043

  19. Femtosecond Heterodyne Transient Grating Studies of Nonradiative Decay of the S2 (11Bu+) State of Peridinin: Detection and Spectroscopic Assignment of an Sx Intermediate State

    Science.gov (United States)

    Ghosh, Soumen; Bishop, Michael M.; Roscioli, Jerome D.; Lafountain, Amy M.; Frank, Harry A.; Beck, Warren F.

    Femtosecond heterodyne transient grating spectroscopy was employed to investigate the nonradiative relaxation dynamics of peridinin from the S2 state to the S1 (21Ag-) state in methanol. A global target analysis indicates that S2 decays in 12 fs to populate an intermediate state, Sx. The absorption and dispersion components of the transient grating signal exhibit a response that is very similar to that of β-carotene in benzonitrile solution. Numerical simulation of the experimental data indicates that the excited state absorption transition from Sx has a larger oscillator strength than that of S1, which rules out an assignment of Sx to a vibrationally excited S1 state. The lifetime of Sx is found to be strongly dependent on the polar solvation timescale. This result indicates that nonradiative decay from Sx to S1 involves large-amplitude torsional motions and a concomitant formation of intramolecular charge transfer character. The present work provides the first evidence that peridinin has an ultrashort S2 lifetime owing to the onset of torsional motions and shows that the Sx acts as an active state for excitation energy transfer to chlorophyll in light-harvesting proteins. Work supported by the Photosynthetic Systems program of U.S. Department of Energy under Award Number DE-SC0010847.

  20. Heterodyne Interferometry in InfraRed at OCA-Calern Observatory in the seventies

    Science.gov (United States)

    Gay, J.; Rabbia, Y.

    2014-04-01

    We report on various works carried four decades ago, so as to develop Heterodyne Interferometry in InfraRed (10 μm) at Calern Observatory (OCA, France), by building an experiment, whose the acronym "SOIRDETE" means "Synthese d'Ouverture en InfraRouge par Detection hETErodyne". Scientific and technical contexts by this time are recalled, as well as basic principles of heterodyne interferometry. The preliminary works and the SOIRDETE experiment are briefly described. Short comments are given in conclusion regarding the difficulties which have prevented the full success of the SOIRDETE experiment.

  1. Homodyning and heterodyning the quantum phase

    Science.gov (United States)

    Dariano, Giacomo M.; Macchiavello, C.; Paris, M. G. A.

    1994-01-01

    The double-homodyne and the heterodyne detection schemes for phase shifts between two synchronous modes of the electromagnetic field are analyzed in the framework of quantum estimation theory. The probability operator-valued measures (POM's) of the detectors are evaluated and compared with the ideal one in the limit of strong local reference oscillator. The present operational approach leads to a reasonable definition of phase measurement, whose sensitivity is actually related to the output r.m.s. noise of the photodetector. We emphasize that the simple-homodyne scheme does not correspond to a proper phase-shift measurements as it is just a zero-point detector. The sensitivity of all detection schemes are optimized at fixed energy with respect to the input state of radiation. It is shown that the optimal sensitivity can be actually achieved using suited squeezed states.

  2. Source-Manipulating Wavelength-Dependent Continuous-Variable Quantum Key Distribution with Heterodyne Detectors

    Science.gov (United States)

    Lv, Geli; Huang, Dazu; Guo, Ying

    2016-05-01

    The intensities of signal and local oscillator (LO) can be elegantly manipulated for the noise-based quantum system while manipulating the wavelength-dependent modulation in source to increase the performance of the continuous-variable key distribution in terms of the secret key rate and maximal transmission distance. The source-based additional noises can be tuned and stabilized to the suitable values to eliminate the effect of the LO fluctuations and defeat the potential attacks in imperfect quantum channels. It is firmly proved that the secret key rate can be manipulated in source over imperfect channels by the intensities of signal and LO with different wavelengths, which have an effect on the optimal signal-to-noise ratio of the heterodyne detectors resulting from the detection efficiency and the additional electronic noise as well. Simulation results show that there is a nice balance between the secret key rate and the maximum transmission distance.

  3. Modified Phasemeter for a Heterodyne Laser Interferometer

    Science.gov (United States)

    Loya, Frank M.

    2010-01-01

    Modifications have been made in the design of instruments of the type described in "Digital Averaging Phasemeter for Heterodyne Interferometry". A phasemeter of this type measures the difference between the phases of the unknown and reference heterodyne signals in a heterodyne laser interferometer. The phasemeter design lacked immunity to drift of the heterodyne frequency, was bandwidth-limited by computer bus architectures then in use, and was resolution-limited by the nature of field-programmable gate arrays (FPGAs) then available. The modifications have overcome these limitations and have afforded additional improvements in accuracy, speed, and modularity. The modifications are summarized.

  4. Noise characteristics of heterodyne/homodyne frequency-domain measurements

    Science.gov (United States)

    Kang, Dongyel; Kupinski, Matthew A.

    2012-01-01

    We theoretically develop and experimentally validate the noise characteristics of heterodyne and/or homodyne measurements that are widely used in frequency-domain diffusive imaging. The mean and covariance of the modulated heterodyne output are derived by adapting the random amplification of a temporal point process. A multinomial selection rule is applied to the result of the temporal noise analysis to additionally model the spatial distribution of intensified photons measured by a charge-coupled device (CCD), which shows that the photon detection efficiency of CCD pixels plays an important role in the noise property of detected photons. The approach of using a multinomial probability law is validated from experimental results. Also, experimentally measured characteristics of means and variances of homodyne outputs are in agreement with the developed theory. The developed noise model can be applied to all photon amplification processes.

  5. Two-wavelength spatial-heterodyne holography

    Science.gov (United States)

    Hanson, Gregory R.; Bingham, Philip R.; Simpson, John T.; Karnowski, Thomas P.; Voelkl, Edgar

    2007-12-25

    Systems and methods are described for obtaining two-wavelength differential-phase holograms. A method includes determining a difference between a filtered analyzed recorded first spatially heterodyne hologram phase and a filtered analyzed recorded second spatially-heterodyned hologram phase.

  6. Quantum noise in laser-interferometer gravitational-wave detectors with a heterodyne readout scheme

    CERN Document Server

    Buonanno, A; Mavalvala, N; Buonanno, Alessandra; Chen, Yanbei; Mavalvala, Nergis

    2003-01-01

    We analyze and discuss the quantum noise in signal-recycled laser interferometer gravitational-wave detectors, such as Advanced LIGO, using a heterodyne readout scheme and taking into account the optomechanical dynamics. Contrary to homodyne detection, a heterodyne readout scheme can simultaneously measure more than one quadrature of the output field, providing an additional way of optimizing the interferometer sensitivity, but at the price of additional noise. Our analysis provides the framework needed to evaluate whether a homodyne or heterodyne readout scheme is more optimal for second generation interferometers from an astrophysical point of view. As a more theoretical outcome of our analysis, we show that as a consequence of the Heisenberg uncertainty principle the heterodyne scheme cannot convert conventional interferometers into (broadband) quantum non-demolition interferometers.

  7. Quasi-balanced two-wave mixing interferometer for remote ultrasound detection

    OpenAIRE

    Hochreiner, Armin; Reitinger, Bernhard; Bouchal, Klaus-Dieter; Zamiri, Saeid; Burgholzer, Peter; Berer, Thomas

    2013-01-01

    We present an improved detection scheme for a two-wave mixing interferometer with a Bi12SiO20 crystal. The proposed detection scheme allows quasi-balanced detection of ultrasonic signals whereby electrical disturbances are suppressed. Quasi-balancing is achieved by changing the polarity of the high voltage at the photorefractive crystal, leading to an inversion of the optical interference signal, in combination with inversion of the detector signal using a signal inverter before the data acqu...

  8. Detecting asymmetries in balance control with system identification: first experimental results from above knee amputees

    NARCIS (Netherlands)

    Kooij, van der H.; Asseldonk, van E.H.F.; Nederhand, M.J.; Driessen, B.; Helder, J.L.; Gelderblom, G.J.

    2007-01-01

    A prosthetic leg can influence balance in various ways, but not all changes in postural performance can easily be identified with the naked clinical eye. Various studies have shown that dynamic posturography is able to detect more subtle changes in balance control. Here, we describe a modification o

  9. Heterodyne 3D ghost imaging

    Science.gov (United States)

    Yang, Xu; Zhang, Yong; Yang, Chenghua; Xu, Lu; Wang, Qiang; Zhao, Yuan

    2016-06-01

    Conventional three dimensional (3D) ghost imaging measures range of target based on pulse fight time measurement method. Due to the limit of data acquisition system sampling rate, range resolution of the conventional 3D ghost imaging is usually low. In order to take off the effect of sampling rate to range resolution of 3D ghost imaging, a heterodyne 3D ghost imaging (HGI) system is presented in this study. The source of HGI is a continuous wave laser instead of pulse laser. Temporal correlation and spatial correlation of light are both utilized to obtain the range image of target. Through theory analysis and numerical simulations, it is demonstrated that HGI can obtain high range resolution image with low sampling rate.

  10. Speckle decorrelation in Ultrasound-modulated optical tomography made by heterodyne holography

    CERN Document Server

    Gross, M

    2016-01-01

    Ultrasound-modulated optical tomography (UOT) is a technique that images optical contrast deep inside scattering media. Heterodyne holography is a promising tool able to detect the UOT tagged photons with high efficiency. In this work, we describe theoretically the detection of the tagged photon in heterodyne holography based UOT, show how to filter the untagged photon discuss, and discuss the effect of speckle decorrelation. We show that optimal detection sensitivity can obtain, if the frame exposure time is of the order of the decorrelation time.

  11. Remote sensing by IR heterodyne spectroscopy

    Science.gov (United States)

    Kostiuk, T.; Mumma, M. J.

    1983-01-01

    The use of infrared heterodyne spectroscopy for the study of planetary atmospheres is discussed. Infrared heterodyne spectroscopy provides a convenient and sensitive method for measuring the true intensity profiles of atmospheric spectral lines. Application of radiative transfer theory to measured lineshapes can then permit the study of molecular abundances, temperatures, total pressures, excitation conditions, and dynamics of the regions of line formation. The theory of formation of atmospheric spectral lines and the retrieval of the information contained in these molecular lines is illustrated. Notable successes of such retrievals from infrared heterodyne measurements on Venus, Mars, Jupiter and the earth are given. A discussion of developments in infrared heterodyne technology is also presented. Previously announced in STAR as N83-28551

  12. Brain white matter lesions detected by magnetic resosnance imaging are associated with balance and gait speed

    OpenAIRE

    John M Starr; Leaper, S A; Murray, A D; Lemmon, H A; Staff, R T; Deary, Ian J.; Whalley, Lawrence J.

    2003-01-01

    Objective: To investigate the relations between premorbid and current mental ability, mood, and white matter signal abnormalities detected by T2 weighted brain magnetic resonance imaging (MRI) and impairment of balance and mobility in older adults. Methods: 97 subjects from the Aberdeen 1921 birth cohort underwent brain MRI, evaluation of balance, and measurement of gait speed. White matter hyperintensities detected on T2 weighted MRI scans were rated by three independent raters on three ...

  13. Balanced Path Routing and Detection Mechanism for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    T.Shanmuga priya

    2013-10-01

    Full Text Available - An Enhanced Dijkstra’s algorithm is presented in this paper. In this proposed approach, a new form of Balanced Path Routing technique is used in which the data send from source node is being transferred to the alternate node and then pass through the nodes to reach the destination. This prevents cuts in between the nodes and gives prior estimation of the shortest route path from source to destination. In Enhanced Dijkstra’s algorithm, the packet delivery ratio is maintained at 80% even when the number of nodes gets increased. This finding indicates that proposed method guarantees reliable communication in wireless sensor networks. The simulation results show the best shortest path with better transmission time.

  14. Mid-infrared photothermal heterodyne spectroscopy in a liquid crystal using a quantum cascade laser.

    Science.gov (United States)

    Mërtiri, Alket; Jeys, Thomas; Liberman, Vladimir; Hong, M K; Mertz, Jerome; Altug, Hatice; Erramilli, Shyamsunder

    2012-07-23

    We report a technique to measure the mid-infrared photothermal response induced by a tunable quantum cascade laser in the neat liquid crystal 4-octyl-4'-cyanobiphenyl (8CB), without any intercalated dye. Heterodyne detection using a Ti:sapphire laser of the response in the solid, smectic, nematic and isotropic liquid crystal phases allows direct detection of a weak mid-infrared normal mode absorption using an inexpensive photodetector. At high pump power in the nematic phase, we observe an interesting peak splitting in the photothermal response. Tunable lasers that can access still stronger modes will facilitate photothermal heterodyne mid-infrared vibrational spectroscopy. PMID:22912508

  15. Mid-infrared photothermal heterodyne spectroscopy in a liquid crystal using a quantum cascade laser

    Science.gov (United States)

    Mërtiri, Alket; Jeys, Thomas; Liberman, Vladimir; Hong, M. K.; Mertz, Jerome; Altug, Hatice; Erramilli, Shyamsunder

    2012-01-01

    We report a technique to measure the mid-infrared photothermal response induced by a tunable quantum cascade laser in the neat liquid crystal 4-octyl-4′-cyanobiphenyl (8CB), without any intercalated dye. Heterodyne detection using a Ti:sapphire laser of the response in the solid, smectic, nematic and isotropic liquid crystal phases allows direct detection of a weak mid-infrared normal mode absorption using an inexpensive photodetector. At high pump power in the nematic phase, we observe an interesting peak splitting in the photothermal response. Tunable lasers that can access still stronger modes will facilitate photothermal heterodyne mid-infrared vibrational spectroscopy. PMID:22912508

  16. Automated reduction of submillimetre single-dish heterodyne data from the James Clerk Maxwell Telescope using ORAC-DR

    CERN Document Server

    Jenness, Tim; Tilanus, Remo P J; Cavanagh, Brad; Berry, David S; Leech, Jamie; Rizzi, Luca

    2015-01-01

    With the advent of modern multi-detector heterodyne instruments that can result in observations generating thousands of spectra per minute it is no longer feasible to reduce these data as individual spectra. We describe the automated data reduction procedure used to generate baselined data cubes from heterodyne data obtained at the James Clerk Maxwell Telescope. The system can automatically detect baseline regions in spectra and automatically determine regridding parameters, all without input from a user. Additionally it can detect and remove spectra suffering from transient interference effects or anomalous baselines. The pipeline is written as a set of recipes using the ORAC-DR pipeline environment with the algorithmic code using Starlink software packages and infrastructure. The algorithms presented here can be applied to other heterodyne array instruments and have been applied to data from historical JCMT heterodyne instrumentation.

  17. Supercontinuum Fourier transform spectrometry with balanced detection on a single photodiode.

    Science.gov (United States)

    Goncharov, Vasily V; Hall, Gregory E

    2016-08-28

    We demonstrate a method of combining a supercontinuum light source with a commercial Fourier transform spectrometer, using a novel approach to dual-beam balanced detection, implemented with phase-sensitive detection on a single light detector. A 40 dB reduction in the relative intensity noise is achieved for broadband light, analogous to conventional balanced detection methods using two matched photodetectors. Unlike conventional balanced detection, however, this method exploits the time structure of the broadband source to interleave signal and reference pulse trains in the time domain, recording the broadband differential signal at the fundamental pulse repetition frequency of the supercontinuum. The method is capable of real-time correction for instability in the supercontinuum spectral structure over a broad range of wavelengths and is compatible with commercially designed spectrometers. A proof-of-principle experimental setup is demonstrated for weak absorption in the 1500-1600 nm region. PMID:27586915

  18. Detection of Bi-Directionality in Strain-Gage Balance Calibration Data

    Science.gov (United States)

    Ulbrich, Norbert

    2012-01-01

    An indicator variable was developed for both visualization and detection of bi-directionality in wind tunnel strain-gage balance calibration data. First, the calculation of the indicator variable is explained in detail. Then, a criterion is discussed that may be used to decide which gage outputs of a balance have bi- directional behavior. The result of this analysis could be used, for example, to justify the selection of certain absolute value or other even function terms in the regression model of gage outputs whenever the Iterative Method is chosen for the balance calibration data analysis. Calibration data of NASA s MK40 Task balance is analyzed to illustrate both the calculation of the indicator variable and the application of the proposed criterion. Finally, bi directionality characteristics of typical multi piece, hybrid, single piece, and semispan balances are determined and discussed.

  19. Quasi-balanced two-wave mixing interferometer for remote ultrasound detection.

    Science.gov (United States)

    Hochreiner, Armin; Reitinger, Bernhard; Bouchal, Klaus-Dieter; Zamiri, Saeid; Burgholzer, Peter; Berer, Thomas

    2013-09-01

    We present an improved detection scheme for a two-wave mixing interferometer with a Bi12SiO20 crystal. The proposed detection scheme allows quasi-balanced detection of ultrasonic signals whereby electrical disturbances are suppressed. Quasi-balancing is achieved by changing the polarity of the high voltage at the photorefractive crystal, leading to an inversion of the optical interference signal, in combination with inversion of the detector signal using a signal inverter before the data acquisition device. The polarity of the high voltage is changed by utilizing an H-bridge consisting of five high-voltage relays. Microcontrollers are used to synchronize the reversion of the high voltage at the photorefractive crystal and the inversion of the measured signals. We demonstrate remote measurement of ultrasonic waves and shown that electrical disturbances are suppressed using the quasi-balanced mode. PMID:24347820

  20. Quasi-balanced two-wave mixing interferometer for remote ultrasound detection

    Science.gov (United States)

    Hochreiner, Armin; Reitinger, Bernhard; Bouchal, Klaus-Dieter; Zamiri, Saeid; Burgholzer, Peter; Berer, Thomas

    2013-09-01

    We present an improved detection scheme for a two-wave mixing interferometer with a Bi12SiO20 crystal. The proposed detection scheme allows quasi-balanced detection of ultrasonic signals whereby electrical disturbances are suppressed. Quasi-balancing is achieved by changing the polarity of the high voltage at the photorefractive crystal, leading to an inversion of the optical interference signal, in combination with inversion of the detector signal using a signal inverter before the data acquisition device. The polarity of the high voltage is changed by utilizing an H-bridge consisting of five high-voltage relays. Microcontrollers are used to synchronize the reversion of the high voltage at the photorefractive crystal and the inversion of the measured signals. We demonstrate remote measurement of ultrasonic waves and shown that electrical disturbances are suppressed using the quasi-balanced mode.

  1. Scanning heterodyne Kerr-effect microscope for imaging of magnetic tracks

    Science.gov (United States)

    Protopopov, Vladimir V.; Lee, Sukwon; Kwon, Youngkun; Cho, Sunghoon; Kim, Hyuk; Chae, Jonggyn

    2006-07-01

    Design and performance of a new type of Kerr microscope based on heterodyne cross-polarized technique is presented. Weak depolarization of the probe beam due to longitudinal magneto-optical Kerr effect is detected by means of heterodyne mixing of the two cross-polarized and frequency shifted waves generated by Zeeman-type He-Ne laser. In comparison with the traditional homodyne method the proposed technique has better sensitivity and spatial resolution. Experimental results of imaging service magnetic tracks on real samples of magnetic disks are presented, showing better contrast and spatial resolution with respect to the images obtained from commercial devices available in the market.

  2. Development of a fast sweep heterodyne microwave reflectometer

    International Nuclear Information System (INIS)

    The density profile of fusion plasmas can be investigated by the reflectometry diagnostic. The measurement principle is based on the radar techniques which calculate the phase shift of a millimeter wave propagating into the plasma and reflected at a cut-off layer. We have tried to describe the density fluctuation effects upon detected signal to understand the disturbing mechanisms which prevent, sometime, the measurement of the phase. First, we have tried to understand the mechanisms and the origin of the turbulence which is responsible for phase disturbance. We point out the role of collisionality ν* and plasma radiation (with the Hugill normalised parameter H) which control the instability. We also demonstrate that the phase delay of the probing wave is very sensitive to the plasma MHD phenomena and is less affected by the micro-turbulence. The second part of this work is the development and the use of a new heterodyne reflectometer. This new diagnostic uses O-mode beam polarisation and works on the 26-36 GHz frequency range. It launches simultaneously into the plasma two frequencies separated by 320 MHz and we can study them separately or with the amplitude modulation technique. It possesses a better sensitivity than the previous homodyne reflectometer and a higher frequency agility. Its heterodyne detection allows us to separate phase and amplitude informations from the detected signal. (author)

  3. A Dispersed Heterodyne Design for the Planet Formation Imager (PFI)

    CERN Document Server

    Ireland, Michael J

    2014-01-01

    The Planet Formation Imager (PFI) is a future world facility that will image the process of planetary formation. It will have an angular resolution and sensitivity sufficient to resolve sub-Hill sphere structures around newly formed giant planets orbiting solar-type stars in nearby star formation regions. We present one concept for this design consisting of twenty-seven or more 4m telescopes with kilometric baselines feeding a mid-infrared spectrograph where starlight is mixed with a frequency-comb laser. Fringe tracking will be undertaken in H-band using a fiber-fed direct detection interferometer, meaning that all beam transport is done by communications band fibers. Although heterodyne interferometry typically has lower signal-to-noise than direct detection interferometry, it has an advantage for imaging fields of view with many resolution elements, because the signal in direct detection has to be split many ways while the signal in heterodyne interferometry can be amplified prior to combining every baseli...

  4. Modified multiphotodiode balanced detection technique for improving SAC-OCDMA networks

    Science.gov (United States)

    Tseng, Shin-Pin

    2015-06-01

    The aim of this study was to develop a feasible modified multiphotodiode balanced detection (MMBD) technique suitable for application in spectral-amplitude-coding optical code-division multiple-access networks, which could mitigate the effect of phase-induced intensity noise (PIIN). Because PIIN is related to the beating between optical signals with wavelengths arriving simultaneously at a balanced photodetector, combining spectral partitioning and an MMBD scheme facilitates reducing PIIN, which tends to dominate performance. Therefore, the system using the proposed scheme exhibited an enhanced performance.

  5. Microwave photonic link with improved phase noise using a balanced detection scheme

    Science.gov (United States)

    Hu, Jingjing; Gu, Yiying; Tan, Wengang; Zhu, Wenwu; Wang, Linghua; Zhao, Mingshan

    2016-07-01

    A microwave photonic link (MPL) with improved phase noise performance using a dual output Mach-Zehnder modulator (DP-MZM) and balanced detection is proposed and experimentally demonstrated. The fundamental concept of the approach is based on the two complementary outputs of DP-MZM and the destructive combination of the photocurrent in balanced photodetector (BPD). Theoretical analysis is performed to numerical evaluate the additive phase noise performance and shows a good agreement with the experiment. Experimental results are presented for 4 GHz, 8 GHz and 12 GHz transmission link and an 11 dB improvement of phase noise performance at 10 MHz offset is achieved compared to the conventional intensity-modulation and direct-detection (IMDD) MPL.

  6. Non-contact FBG sensing based steam turbine rotor dynamic balance vibration detection system

    Science.gov (United States)

    Li, Tianliang; Tan, Yuegang; Cai, Lin

    2015-10-01

    This paper has proposed a non-contact vibration sensor based on fiber Bragg grating sensing, and applied to detect vibration of steam turbine rotor dynamic balance experimental platform. The principle of the sensor has been introduced, as well as the experimental analysis; performance of non-contact FBG vibration sensor has been analyzed in the experiment; in addition, turbine rotor dynamic vibration detection system based on eddy current displacement sensor and non-contact FBG vibration sensor have built; finally, compared with results of signals under analysis of the time domain and frequency domain. The analysis of experimental data contrast shows that: the vibration signal analysis of non-contact FBG vibration sensor is basically the same as the result of eddy current displacement sensor; it verified that the sensor can be used for non-contact measurement of steam turbine rotor dynamic balance vibration.

  7. A heterodyne interferometer for angle metrology

    International Nuclear Information System (INIS)

    We have developed a compact, high-resolution, angle measurement instrument based on a heterodyne interferometer. Common-path heterodyne interferometer metrology is used to measure displacements of a reflective target surface. In the interferometer set up, an optical mask is used to sample the laser beam reflecting back from four areas on a target surface. From the relative displacement measurements of the target surface areas, we can simultaneously determine angular rotations around two orthogonal axes in a plane perpendicular to the measurement beam propagation direction. The device is used in a testbed for a tracking telescope system where pitch and yaw angle measurements of a flat mirror are performed. Angle noise measurement of the device shows 0.1 nrad/√(Hz) at 1 Hz, at a working distance of 1 m. The operation range and nonlinearity of the device when used with a flat mirror is approximately ±0.15 mrad, and 3 μrad rms, respectively.

  8. Spatial-heterodyne interferometry for transmission (SHIFT) measurements

    Science.gov (United States)

    Bingham, Philip R.; Hanson, Gregory R.; Tobin, Ken W.

    2006-10-10

    Systems and methods are described for spatial-heterodyne interferometry for transmission (SHIFT) measurements. A method includes digitally recording a spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis using a reference beam, and an object beam that is transmitted through an object that is at least partially translucent; Fourier analyzing the digitally recorded spatially-heterodyned hologram, by shifting an original origin of the digitally recorded spatially-heterodyned hologram to sit on top of a spatial-heterodyne carrier frequency defined by an angle between the reference beam and the object beam, to define an analyzed image; digitally filtering the analyzed image to cut off signals around the original origin to define a result; and performing an inverse Fourier transform on the result.

  9. SHIMS -- A Spatial Heterodyne Interferometer for Methane Sounding Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This project develops the Spatial Heterodyne Interferometer for Methane Sounding (SHIMS), a lightweight, compact, robust spectrometer system for remote sensing of...

  10. Balancing detection and eradication for control of epidemics: sudden oak death in mixed-species stands.

    Directory of Open Access Journals (Sweden)

    Martial L Ndeffo Mbah

    Full Text Available Culling of infected individuals is a widely used measure for the control of several plant and animal pathogens but culling first requires detection of often cryptically-infected hosts. In this paper, we address the problem of how to allocate resources between detection and culling when the budget for disease management is limited. The results are generic but we motivate the problem for the control of a botanical epidemic in a natural ecosystem: sudden oak death in mixed evergreen forests in coastal California, in which species composition is generally dominated by a spreader species (bay laurel and a second host species (coast live oak that is an epidemiological dead-end in that it does not transmit infection but which is frequently a target for preservation. Using a combination of an epidemiological model for two host species with a common pathogen together with optimal control theory we address the problem of how to balance the allocation of resources for detection and epidemic control in order to preserve both host species in the ecosystem. Contrary to simple expectations our results show that an intermediate level of detection is optimal. Low levels of detection, characteristic of low effort expended on searching and detection of diseased trees, and high detection levels, exemplified by the deployment of large amounts of resources to identify diseased trees, fail to bring the epidemic under control. Importantly, we show that a slight change in the balance between the resources allocated to detection and those allocated to control may lead to drastic inefficiencies in control strategies. The results hold when quarantine is introduced to reduce the ingress of infected material into the region of interest.

  11. Lithium-Ion Battery Cell-Balancing Algorithm for Battery Management System Based on Real-Time Outlier Detection

    OpenAIRE

    Changhao Piao; Zhaoguang Wang; Ju Cao; Wei Zhang; Sheng Lu

    2015-01-01

    A novel cell-balancing algorithm which was used for cell balancing of battery management system (BMS) was proposed in this paper. Cell balancing algorithm is a key technology for lithium-ion battery pack in the electric vehicle field. The distance-based outlier detection algorithm adopted two characteristic parameters (voltage and state of charge) to calculate each cell’s abnormal value and then identified the unbalanced cells. The abnormal and normal type of battery cells were acquired by on...

  12. Efficacy of the Star Excursion Balance Tests in Detecting Reach Deficits in Subjects With Chronic Ankle Instability

    OpenAIRE

    Olmsted, Lauren C.; Carcia, Christopher R; Hertel, Jay; Shultz, Sandra J

    2002-01-01

    Objective: Chronic instability after lateral ankle sprain has been shown to cause balance deficits during quiet standing. Although static balance assessment in those with ankle instability has been thoroughly examined in the literature, few researchers have studied performance on more dynamic tasks. Our purpose was to determine if the Star Excursion Balance Tests (SEBTs), lower extremity reach tests, can detect deficits in subjects with chronic ankle instability.

  13. NMR parallel Q-meter with double-balanced-mixer detection for polarized target experiments

    International Nuclear Information System (INIS)

    A constant-voltage, parallel-tuned nuclear magnetic resonance (NMR) circuit, patterned after a Liverpool design, has been developed for polarized target experiments. Measuring the admittance of the resonance circuit allows advantageous use of double-balanced mixer detection. The resonant circuit is tolerant of stray capacitance between the NMR coil and the target cavity, thus easing target-cell-design constraints. The reference leg of the circuit includes a voltage-controlled attenuator and phase shifter for ease of tuning. The NMR output features a flat background and has good linearity and stability

  14. Measuring Cyclic Error in Laser Heterodyne Interferometers

    Science.gov (United States)

    Ryan, Daniel; Abramovici, Alexander; Zhao, Feng; Dekens, Frank; An, Xin; Azizi, Alireza; Chapsky, Jacob; Halverson, Peter

    2010-01-01

    An improved method and apparatus have been devised for measuring cyclic errors in the readouts of laser heterodyne interferometers that are configured and operated as displacement gauges. The cyclic errors arise as a consequence of mixing of spurious optical and electrical signals in beam launchers that are subsystems of such interferometers. The conventional approach to measurement of cyclic error involves phase measurements and yields values precise to within about 10 pm over air optical paths at laser wavelengths in the visible and near infrared. The present approach, which involves amplitude measurements instead of phase measurements, yields values precise to about .0.1 microns . about 100 times the precision of the conventional approach. In a displacement gauge of the type of interest here, the laser heterodyne interferometer is used to measure any change in distance along an optical axis between two corner-cube retroreflectors. One of the corner-cube retroreflectors is mounted on a piezoelectric transducer (see figure), which is used to introduce a low-frequency periodic displacement that can be measured by the gauges. The transducer is excited at a frequency of 9 Hz by a triangular waveform to generate a 9-Hz triangular-wave displacement having an amplitude of 25 microns. The displacement gives rise to both amplitude and phase modulation of the heterodyne signals in the gauges. The modulation includes cyclic error components, and the magnitude of the cyclic-error component of the phase modulation is what one needs to measure in order to determine the magnitude of the cyclic displacement error. The precision attainable in the conventional (phase measurement) approach to measuring cyclic error is limited because the phase measurements are af-

  15. Ultra fast frequency sweep heterodyne reflectometer on the Tore Supra tokamak

    International Nuclear Information System (INIS)

    A new O-Mode dual frequency heterodyne reflectometer has been installed on Tore Supra, introducing outstanding improvement of the phase determination due high dynamic heterodyne detection, and ultra fast sweeps capabilities (10 μs) provided by the solid state source HTOs. This system operates with O-mode electric field polarization in the range of 26 - 36 GHz and has been designed for density profile measurements. The reflectometer launches simultaneously into the plasma two frequencies separated by 320 MHz. The heterodyne detection improves the dynamic, up to 60 db, and is associated with an I.Q. detection to allow separate analysis of amplitude and phase of each reflected signals of both probing waves. Therefore, to calculate the density profile, the group delay can be defined in two different ways: from the derivative of the absolute phase of one of the two probing waves or by calculating the phase difference between the two probing waves. It is explained how ultra fast sweep operations (down to 10 μs) significantly reduce the influence of the plasma turbulence upon the phase measurements. It is also pointed out the importance of filtering carefully the detected signal in order to keep only the information coming from the reflection at the cut-off and to get rid of parasitic reflections. It is shown that the phase difference technique does not remove completely fluctuations such as long radial correlation MHD perturbation. Density profiles determined by the heterodyne reflectometer are in good agreement with the measurements from the other diagnostics of Tore Supra. (author)

  16. Optical beat interference noise reduction in OFDMA optical access link using self-homodyne balanced detection

    Science.gov (United States)

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

    2013-12-01

    A Novel technique for reducing the OBI noise in optical OFDMA-PON uplink is presented. OFDMA is a multipleaccess/ multiplexing scheme that can provide multiplexing operation of user data streams onto the downlink sub-channels and uplink multiple access by means of dividing OFDM subcarriers as sub-channels. The main issue of high-speed, single-wavelength upstream OFDMA-PON arises from optical beating interference noise. Because the sub-channels are allocated dynamically to multiple access users over same nominal wavelength, it generates the optical beating interference among upstream signals. In this paper, we proposed a novel scheme using self-homodyne balanced detection in the optical line terminal (OLT) to reduce OBI noise which is generated in the uplink transmission of OFDMA-PON system. When multiple OFDMA sub-channels over the same nominal wavelength are received at the same time in the proposed architecture, OBI noises can be removed using balanced detection. Using discrete multitone modulation (DMT) to generate real valued OFDM signals, the proposed technique is verified through experimental demonstration.

  17. BER Analysis Using Beat Probability Method of 3D Optical CDMA Networks with Double Balanced Detection

    Directory of Open Access Journals (Sweden)

    Chih-Ta Yen

    2015-01-01

    Full Text Available This study proposes novel three-dimensional (3D matrices of wavelength/time/spatial code for code-division multiple-access (OCDMA networks, with a double balanced detection mechanism. We construct 3D carrier-hopping prime/modified prime (CHP/MP codes by extending a two-dimensional (2D CHP code integrated with a one-dimensional (1D MP code. The corresponding coder/decoder pairs were based on fiber Bragg gratings (FBGs and tunable optical delay lines integrated with splitters/combiners. System performance was enhanced by the low cross correlation properties of the 3D code designed to avoid the beat noise phenomenon. The CHP/MP code cardinality increased significantly compared to the CHP code under the same bit error rate (BER. The results indicate that the 3D code method can enhance system performance because both the beating terms and multiple-access interference (MAI were reduced by the double balanced detection mechanism. Additionally, the optical component can also be relaxed for high transmission scenery.

  18. Modeling of the balanced bridge mine detection sensor using the transmission line matrix (TLM) technique

    Science.gov (United States)

    Sherbondy, Kelly D.

    1995-06-01

    A numerical time-domain technique known as the transmission line matrix (TLM) method is used to analyze a ground penetrating radar (GPR) concept known historically as balanced bridge. This GPR concept is a dielectric anomaly (mine) detection sensor which operates in the UHF frequency band. This mine sensor consists of two receive broadband antennas separated by a single center transmit antenna. Traditionally, if care is taken in the construction of the antennas, the direct coupling and ground reflection energies are combined and nulled out by a hardware coupler when the sensor configuration is over homogeneous soil. When one of the two receiving antennas is over a dielectric anomaly (mine), the differenced energies from the two receiving antennas no longer produces a null and a peaked response is observed. This mine sensing technique has performed well under experimental tests at Fort Belvoir and Fort A.P. Hill, Virginia. Testing results, at different sites using different mine types, have indicated the sensor's performance in terms of probability of detection and false-alarm rates. The TLM method is used to describe the balanced bridge mine detector's response to targets and clutter as well as its unique capabilities in an attempt to shed light into occurring fundamental wave interactions.

  19. Heterodyne Interferometric Temperature Sensor Using a Transverse Zeeman Laser and a Polarization Maintaining Fiber

    Science.gov (United States)

    Kawata, S.; Shigeoka, T.; Okamoto, T.; Minami, S.

    1986-01-01

    A new fiber-optic temperature sesnor using a polarization maintaining fiber and a transverse Zeeman laser based on heterodyne interferometry has been developed. The temperature variation is detected by coupling two orthogonal linear polirization components of a laser beam, each differently phase-modulated during transmitting a birefringent single-mode polarization maintaining fiber. A transverse He-Ne Zeeman laser was developed to achieve heterodyning demodulation of the phase-shift caused by the temperature of the fiber. Experimental result demonstrates that this sensor has the temperature resolution of 0.0032°C with a very wide dynamic range. Besides, this fiber sensor has the advantages of simple construction and ruggedness against pressure turbulence.

  20. Heterodyne interferometry method for calibration of a Soleil-Babinet compensator.

    Science.gov (United States)

    Zhang, Wenjing; Zhang, Zhiwei

    2016-05-20

    A method based on the common-path heterodyne interferometer system is proposed for the calibration of a Soleil-Babinet compensator. In this heterodyne interferometer system, which consists of two acousto-optic modulators, the compensator being calibrated is inserted into the signal path. By using the reference beam as the benchmark and a lock-in amplifier (SR844) as the phase retardation collector, retardations of 0 and λ (one wavelength) can be located accurately, and an arbitrary retardation between 0 and λ can also be measured accurately and continuously. By fitting a straight line to the experimental data, we obtained a linear correlation coefficient (R) of 0.995, which indicates that this system is capable of linear phase detection. The experimental results demonstrate determination accuracies of 0.212° and 0.26° and measurement precisions of 0.054° and 0.608° for retardations of 0 and λ, respectively. PMID:27411154

  1. [Study on the Technology of the 4.4 μm Mid-Infrared Laser Heterodyne Spectrum].

    Science.gov (United States)

    Tan, Tu; Cao, Zhen-song; Wang, Gui-shi; Wang, Lei; Liu, Kun; Huang, Yin-bo; Chen Wei-dong; Gao, Wei-ming

    2015-06-01

    In this paper, first time as our knowledge, we describe the development and performance evaluation of a 4.4 μm external cavity quantum cascade laser based laser heterodyne radiometer. Laser heterodyne spectroscopy is a high sensitive laser spectroscopy technique which offers the potential to develop a compact ground or satellite based radiometer for Earth observation and astronomy. An external cavity quantum cascade laser operating at 4. 4 μm, with output power up to 180 mW and narrow line width was used as a local oscillation. The external cavity quantum cascade laser offers wide spectral tuning range, it is tunable from 4.38 to 4.52 μm with model hop free and can be used for simultaneous detections of CO2, CO and N2 O. A blackbody was used as a signal radiation source. Development and fundamental theory of Laser heterodyne spectroscopy was described. The performance of the developed Laser heterodyne radiometer was evaluated by measuring of CO2 spectral at different pressures. Analyses results showed that a signal-to-noise ratio of 86 was achieved which was less than the theoretical value of 287. The spectral resolution of the developed Laser heterodyne spectroscopy is about 0.007 8 cm(-1) which could meet the requirement of high resolution spectroscopy measurement in the case of Doppler linewidth. The experiment showed that middle Infrared laser heterodyne spectroscopy system had high signal-to-noise ratio and spectral resolution, and had broad application prospect in high precision measurement of atmospheric greenhouse gas concentration and vertical profile. PMID:26601358

  2. Characterization of new components for a miniaturized heterodyne infrared spectrometer

    Science.gov (United States)

    Krause, Pia; Sonnabend, Guido; Labadie, Lucas; Sornig, Manuela; Thomson, Robert; Arriola, Alexander; Rodenas, Arian; Hewagama, Tilak; Rutz, Frank

    2014-08-01

    We report on the development and testing of the building blocks of a possible compact heterodyne setup in the mid-infrared, which becomes particularly relevant for flight instrumentation. The local oscillator is a Quantum Cascade Laser (QCL) source at 8.6 μm operable at room temperature. The beam combination of the source signal and the local oscillator will occur by means of integrated optics for the 10 μm range, which was characterized in the lab. In addition we investigate the use of superlattice detectors in a heterodyne instrument. This work shows that these different new components can become valuable tools for a compact heterodyne setup.

  3. Balanced Multi-Label Propagation for Overlapping Community Detection in Social Networks

    Institute of Scientific and Technical Information of China (English)

    Zhi-Hao Wu; You-Fang Lin; Steve Gregory; Huai-Yu Wan; Sheng-Feng Tian

    2012-01-01

    In this paper,we propose a balanced multi-label propagation algorithm (BMLPA) for overlapping community detection in social networks. As well as its fast speed,another important advantage of our method is good stability,which other multi-label propagation algorithms,such as COPRA,lack.In BMLPA,we propose a new update strategy,which requires that community identifiers of one vertex should have balanced belonging coefficients.The advantage of this strategy is that it allows vertices to belong to any number of communities without a global limit on the largest number of community memberships,which is needed for COPRA.Also,we propose a fast method to generate "rough cores",which can be used to initialize labels for multi-label propagation algorithms,and are able to improve the quality and stability of results.Experimental results on synthetic and real social networks show that BMLPA is very efficient and effective for uncovering overlapping communities.

  4. Femtosecond Heterodyne Transient Grating Studies of Nonradiative Deactivation of the S2 (1(1)Bu(+)) State of Peridinin: Detection and Spectroscopic Assignment of an Intermediate in the Decay Pathway.

    Science.gov (United States)

    Ghosh, Soumen; Bishop, Michael M; Roscioli, Jerome D; LaFountain, Amy M; Frank, Harry A; Beck, Warren F

    2016-04-21

    Femtosecond heterodyne transient grating spectroscopy was employed to investigate the nonradiative decay pathway from the S2 (1(1)Bu(+)) state to the S1 (2(1)Ag(-)) state of peridinin in methanol solution. Just as previously observed by this laboratory for β-carotene in benzonitrile, the real (absorption) and imaginary (dispersion) components of the transient grating signal obtained with Fourier transform spectral interferometry from peridinin exhibit ultrafast responses indicating that S2 state decays in 12 fs to produce an intermediate state, Sx. The excited state absorption spectrum from the Sx state of peridinin, however, is found to be markedly blue-shifted from that of β-carotene because it makes a substantial contribution to the signal observed with 40 fs, 520 nm pulses. The results of a global target analysis and numerical simulations using nonlinear response functions and the multimode Brownian oscillator model support the assignment of Sx to a displaced conformation of the S2 state rather than to a vibrationally excited (or hot) S1 state. The Sx state in peridinin is assigned to a structure with a distorted conjugated polyene backbone moving past an activation-energy barrier between planar and twisted structures on the S2 potential surface. The lengthened lifetime of the Sx state of peridinin in methanol, 900 ± 100 fs, much longer than that typically observed for carotenoids lacking carbonyl substituents, ∼150 fs, can be attributed to the slowing of torsional motions by solvent friction. In peridinin, the system-bath coupling is significantly enhanced over that in β-carotene solution most likely due to the intrinsic intramolecular charge transfer character it derives from the electron withdrawing nature of the carbonyl substituent. An important additional implication is that the Sx state, and the distorted structures reached subsequently along the torsional gradient on the S2 potential surface, may serve as the principal excitation energy transfer

  5. Optical correction using fourier transform heterodyne

    Science.gov (United States)

    Laubscher, Bryan E.; Nemzek, Robert J.; Cooke, Bradly J.; Olivas, Nicholas L.; Jorgensen, Anders M.; Smith, J. A.; Weisse-Bernstein, Nina R.

    2005-08-01

    In this paper we briefly present the theory of Fourier Transform Heterodyne (FTH), describe past verification experiments carried out, and discuss the experiment designed to use this new imaging technology to perform optical correction. FTH uses the scalar projection of a reference laser beam and a test laser beam onto a single element detector. The complex current in the detector yields the coefficient of the scalar projection. By projecting a complete orthonormal basis set of reference beams onto the test beam, the amplitude and phase of the test beam can be measured, allowing the reconstruction of the phasefront of the image. Experiments to determine this technique's applicability to optical correction and optical self-correction are continuing. Applications of this technique beyond optical correction include adaptive optics; interferometry; and active, high background, low signal imaging.

  6. Video-rate computational heterodyne holography

    CERN Document Server

    Dillée, Antoine; Lopes, Fernando; Atlan, Michael

    2014-01-01

    We present a versatile computational image rendering software of optically-acquired holograms. The reported software can process 4 Megapixel 8-bit raw frames from a sensor array acquired at a sustained rate of 80 Hz. Video-rate image rendering is achieved by streamline image processing with commodity computer graphics hardware. For time-averaged holograms acquired in off-axis optical configuration with a frequency-shifted reference beam, wide-field imaging of one tunable spectral component is permitted. This software is validated by phase-stepped hologram rendering, and non-contact monitoring of surface acoustic waves by single and dual sideband hologram rendering. It demonstrates the suitability of holography for video-rate computational laser Doppler imaging in heterodyne optical configuration.

  7. A shaped annular beam tri-heterodyne confocal microscope with good anti-environmental interference capability

    Institute of Scientific and Technical Information of China (English)

    Zhao Wei-Qian; Feng Zheng-De; Qiu Li-Rong

    2007-01-01

    A shaped annular beam tri-heterodyne confocal microscope has been proposed to improve the anti-environmental interference capability and the resolution of a confocal microscope. It simultaneously detects far-, on-, and near-focus signals with given phase differences by dividing the measured light path of the confocal microscope into three sub-paths (signals). Pair-wise real-time heterodyne subtraction of the three signals is used to improve the anti-environmental interference capability, axial resolution, and linearity; and a shaped annular beam super-resolution technique is used to improve lateral resolution. Theoretical analyses and preliminary experiments indicate that an axial resolution of about 1 nm can be achieved with a shaped annular beam tri-heterodyne confocal microscope and its lateral resolution can be better than 0.2μm for λ= 632.8 nm, the numerical aperture of the lens of the microscope is NA = 0.85, and the normalized radius ε= 0.5.

  8. Subsurface-AFM: sensitivity to the heterodyne signal

    International Nuclear Information System (INIS)

    Applying heterodyne force microscopy (HFM), it has been impressively demonstrated that it is possible to obtain subsurface information: 20 nm large gold nanoparticles that were buried 500 nm deep have been imaged. It is the heterodyne signal that contains the subsurface information. We elucidate, both theoretically and experimentally, the sensitivity to the heterodyne signal as a function of the tip–sample distance. This is crucial information for experiments as the distance, and therefore the sensitivity, is tunable. We show that the amplitude of the heterodyne signal has a local maximum in the attractive part of the tip–sample interaction, before it surprisingly reaches an even higher plateau, when the tip–sample interaction is repulsive. This can only be explained by a non-decreasing amplitude of the ultrasonic motion of the tip, although it is in full contact with the surface. We confirm this counterintuitive tip behavior experimentally even on a hard surface like silicon. (paper)

  9. Development of a fast sweep heterodyne microwave reflectometer; Developpement d`un reflectometre micro-onde heterodyne a balayage ultra rapide

    Energy Technology Data Exchange (ETDEWEB)

    Moreau, Ph. [Association Euratom-CEA, Centre d`Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee]|[Universite de Provence, 13 - Marseille (France)

    1997-12-01

    The density profile of fusion plasmas can be investigated by the reflectometry diagnostic. The measurement principle is based on the radar techniques which calculate the phase shift of a millimeter wave propagating into the plasma and reflected at a cut-off layer. We have tried to describe the density fluctuation effects upon detected signal to understand the disturbing mechanisms which prevent, sometime, the measurement of the phase. First, we have tried to understand the mechanisms and the origin of the turbulence which is responsible for phase disturbance. We point out the role of collisionality {nu}{sup *} and plasma radiation (with the Hugill normalised parameter H) which control the instability. We also demonstrate that the phase delay of the probing wave is very sensitive to the plasma MHD phenomena and is less affected by the micro-turbulence. The second part of this work is the development and the use of a new heterodyne reflectometer. This new diagnostic uses O-mode beam polarisation and works on the 26-36 GHz frequency range. It launches simultaneously into the plasma two frequencies separated by 320 MHz and we can study them separately or with the amplitude modulation technique. It possesses a better sensitivity than the previous homodyne reflectometer and a higher frequency agility. Its heterodyne detection allows us to separate phase and amplitude informations from the detected signal. (author) 93 refs.

  10. Faster processing of multiple spatially-heterodyned direct to digital holograms

    Science.gov (United States)

    Hanson, Gregory R [Clinton, TN; Bingham, Philip R [Knoxville, TN

    2008-09-09

    Systems and methods are described for faster processing of multiple spatially-heterodyned direct to digital holograms. A method includes of obtaining multiple spatially-heterodyned holograms, includes: digitally recording a first spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis; digitally recording a second spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis; Fourier analyzing the recorded first spatially-heterodyned hologram by shifting a first original origin of the recorded first spatially-heterodyned hologram including spatial heterodyne fringes in Fourier space to sit on top of a spatial-heterodyne carrier frequency defined as a first angle between a first reference beam and a first object beam; applying a first digital filter to cut off signals around the first original origin and performing an inverse Fourier transform on the result; Fourier analyzing the recorded second spatially-heterodyned hologram by shifting a second original origin of the recorded second spatially-heterodyned hologram including spatial heterodyne fringes in Fourier space to sit on top of a spatial-heterodyne carrier frequency defined as a second angle between a second reference beam and a second object beam; and applying a second digital filter to cut off signals around the second original origin and performing an inverse Fourier transform on the result, wherein digitally recording the first spatially-heterodyned hologram is completed before digitally recording the second spatially-heterodyned hologram and a single digital image includes both the first spatially-heterodyned hologram and the second spatially-heterodyned hologram.

  11. Broadband Infrared Heterodyne Spectrometer: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, C G; Cunningham, C T; Tringe, J W

    2010-12-16

    This report summarizes the most important results of our effort to develop a new class of infrared spectrometers based on a novel broadband heterodyne design. Our results indicate that this approach could lead to a near-room temperature operation with performance limited only by quantum noise carried by the incoming signal. Using a model quantum-well infrared photodetector (QWIP), we demonstrated key performance features of our approach. For example, we directly measured the beat frequency signal generated by superimposing local oscillator (LO) light of one frequency and signal light of another through a spectrograph, by injecting the LO light at a laterally displaced input location. In parallel with the development of this novel spectrometer, we modeled a new approach to reducing detector volume though plasmonic resonance effects. Since dark current scales directly with detector volume, this ''photon compression'' can directly lead to lower currents. Our calculations indicate that dark current can be reduced by up to two orders of magnitude in an optimized ''superlens'' structure. Taken together, our spectrometer and dark current reduction strategies provide a promising path toward room temperature operation of a mid-wave and possibly long-wave infrared spectrometer.

  12. Gain Stabilization of a Submillimeter SIS Heterodyne Receiver

    CERN Document Server

    Battat, James; Hunter, Todd R; Kimberk, Robert; Leiker, Patrick S; Tong, Cheuk-yu Edward

    2007-01-01

    We have designed a system to stabilize the gain of a submillimeter heterodyne receiver against thermal fluctuations of the mixing element. In the most sensitive heterodyne receivers, the mixer is usually cooled to 4 K using a closed-cycle cryocooler, which can introduce ~1% fluctuations in the physical temperature of the receiver components. We compensate for the resulting mixer conversion gain fluctuations by monitoring the physical temperature of the mixer and adjusting the gain of the intermediate frequency (IF) amplifier that immediately follows the mixer. This IF power stabilization scheme, developed for use at the Submillimeter Array (SMA), a submillimeter interferometer telescope on Mauna Kea in Hawaii, routinely achieves a receiver gain stability of 1 part in 6,000 (rms to mean). This is an order of magnitude improvement over the typical uncorrected stability of 1 part in a few hundred. Our gain stabilization scheme is a useful addition to SIS heterodyne receivers that are cooled using closed-cycle cr...

  13. Infrared heterodyne spectroscopy of astronomical and laboratory sources at 8.5 micron. [absorption line profiles of nitrogen oxide and black body emission from Moon and Mars

    Science.gov (United States)

    Mumma, M.; Kostiuk, T.; Cohen, S.; Buhl, D.; Vonthuna, P. C.

    1974-01-01

    The first infrared heterodyne spectrometer using tuneable semiconductor (PbSe) diode lasers has been constructed and was used near 8.5 micron to measure absorption line profiles of N2O in the laboratory and black body emission from the Moon and from Mars. Spectral information was recorded over a 200 MHz bandwidth using an 8-channel filter bank. The resolution was 25 MHz and the minimum detectable (black body) power was 1 x 10 to the minus 16th power watts for 8 minutes of integration. The results demonstrate the usefulness of heterodyne spectroscopy for the study of remote and local sources in the infrared.

  14. Resolution beyond classical limits with spatial frequency heterodyning

    Institute of Scientific and Technical Information of China (English)

    A. Mudassar; A. R. Harvey; A. H. Greenaway; J. D. C. Jones

    2006-01-01

    @@ A technique for coherent imaging based on spatial frequency heterodyning is described. Three images corresponding to three physical measurements are recorded. For the first measurement, a scene is simply illuminated with a coherent beam and for measurements 2 and 3, the scene is projected with cosine and sine fringes, respectively. Due to spatial frequency heterodyning, upper and lower side band information falls in the pass band of the imager. These bands are separated and correct phases and positions are assigned to these bands in the spatial frequency domain. An extension of bandwidth is achieved in the frequency domain and the inverse frequency domain data then give a high resolution coherent image.

  15. Integrated photonic decoder with complementary code processing and balanced detection for two-dimensional optical code division multiple access.

    Science.gov (United States)

    Takiguchi, K; Okuno, M; Takahashi, H; Moriwaki, O

    2007-04-01

    We propose a novel integrated photonic decoder for two-dimensional (time spreading, wavelength hopping) optical code division multiple access. The decoder is composed of multiplexers-demultiplexers, variable delay lines, and a coupler, which processes complementary codes and utilizes balanced detection to reduce unwanted cross-correlation interference. We successfully carried out a 10 Gbit/s transmission that demonstrated its effectiveness. PMID:17339936

  16. Modelling of Walking Humanoid Robot With Capability of Floor Detection and Dynamic Balancing Using Colored Petri Net

    OpenAIRE

    Pashazadeh, Saeid; Saeedvand, Saeed

    2014-01-01

    Most humanoid robots have highly complicated structure and design of robots that are very similar to human is extremely difficult. In this paper, modelling of a general and comprehensive algorithm for control of humanoid robots is presented using Colored Petri Nets. For keeping dynamic balance of the robot, combination of Gyroscope and Accelerometer sensors are used in algorithm. Image processing is used to identify two fundamental issues: first, detection of target or an object which robot m...

  17. Experimental study on minimum resolvable velocity for heterodyne laser Doppler vibrometry

    Institute of Scientific and Technical Information of China (English)

    Jianhua Shang; Shuguang Zhao; Yan He; Weibiao Chen; Ning Jia

    2011-01-01

    A high spatial resolution, high velocity resolution all-fiber laser Doppler vibrornetry (LDV) based on heterodyne detection for vibration measurements is reported. A linewidth of 1-kHz single-mode continuous fiber laser, polarization-preserving fiber, and a telescope with 30-mm aperture are used in this LDV. With the inphase-quadrature circuit and the digital differentiating discriminator, a high velocity resolution of 96.9 nm/s and a high displacement resolution of 2.5 pm are obtained simultaneously with a glass attached to a piezoceramic transducer. These values correspond to the measurement uncertainties of vibration velocity and displacement within 4.14% and 4.6%, respectively.%@@ A high spatial resolution,high velocity resolution all-fiber laser Doppler vibrometry(LDV) based on heterodyne detection for vibration measurements is reported.A linewidth of 1-kHz single-mode continuous fiber laser,polarization-preserving fiber,and a telescope with 30-mm aperture are used in this LDV.

  18. Heterodyne detector for measuring the characteristic of elliptically polarized microwaves

    DEFF Research Database (Denmark)

    Leipold, Frank; Nielsen, Stefan Kragh; Michelsen, Susanne

    2008-01-01

    perpendicular orientated pickup waveguides. A heterodyne technique mixes the microwave frequency down to frequencies on the order of 200 MHz. An oscilloscope is used to determine the relative amplitudes of the electrical fields and the phase shift in between, from which the three characteristic parameters can...

  19. A Spatial Heterodyne Spectrometer for Laboratory Astrophysics; First Interferogram

    Science.gov (United States)

    Lawler, J. E.; Labby, Z. E.; Roesler, F. L.; Harlander, J.

    2006-01-01

    A Spatial Heterodyne Spectrometer with broad spectral coverage across the VUV - UV region and with a high (> 500,000 ) spectral resolving power is being built for laboratory measurements of spectroscopic data including emission branching fractions, improved level energies, and hyperfine/isotopic parameters.

  20. A broadband, high-resolution spatial heterodyne spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Lawler, J E; Roesler, F L; Labby, Z [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Harlander, J [Department of Physics, Astronomy, and Engineering Science, St. Cloud State University, St. Cloud, MN 56301 (United States)], E-mail: jelawler@wisc.edu

    2009-05-15

    Design and performance parameters of a broadband, high-resolution spatial heterodyne spectrometer (SHS) with a transmitting beamsplitter are described. This Mark 1 SHS achieves more than a factor of five in continuous wavenumber coverage with a resolving power in hundreds of thousands. Progress toward an all reflection, broadband, high-resolution Mark 2 SHS is reported.

  1. Oral Dalfampridine Improves Standing Balance Detected at Static Posturography in Multiple Sclerosis

    Science.gov (United States)

    Prosperini, Luca; Fortuna, Deborah; Marchetti, Maria Rita

    2014-01-01

    We report a 14-week post-marketing experience on 20 patients with multiple sclerosis (MS) who started prolonged-release (PR) oral dalfampridine 10 mg twice daily according to European Medicine Agency criteria. They underwent serial static posturography assessments and the dizziness handicap inventory (DHI) to investigate whether PR dalfampridine could impact standing balance and self-reported perception of balance. The incidence of accidental falls per person per month was also recorded throughout the study. Eight (40%) patients, who had a relevant improvement in walking speed, were defined as treatment responders. They showed a significant improvement of standing balance (with respect to pretreatment assessment) when contrasted with 12 (60%) nonresponders (F[4,15] = 3.959, P = 0.027). No significant changes in DHI score, as well as in its functional, physical, and emotional subscales, were found in both responders and nonresponders at the end of study (all P values are ≥0.2). Treatment response did not affect the incidence of accidental falls. Future studies based on larger sample sizes, and with longer followup, are required to confirm the beneficial effect of PR dalfampridine on standing balance. PMID:24800078

  2. Oral Dalfampridine Improves Standing Balance Detected at Static Posturography in Multiple Sclerosis

    Directory of Open Access Journals (Sweden)

    Luca Prosperini

    2014-01-01

    Full Text Available We report a 14-week post-marketing experience on 20 patients with multiple sclerosis (MS who started prolonged-release (PR oral dalfampridine 10 mg twice daily according to European Medicine Agency criteria. They underwent serial static posturography assessments and the dizziness handicap inventory (DHI to investigate whether PR dalfampridine could impact standing balance and self-reported perception of balance. The incidence of accidental falls per person per month was also recorded throughout the study. Eight (40% patients, who had a relevant improvement in walking speed, were defined as treatment responders. They showed a significant improvement of standing balance (with respect to pretreatment assessment when contrasted with 12 (60% nonresponders (F[4,15] = 3.959, P=0.027. No significant changes in DHI score, as well as in its functional, physical, and emotional subscales, were found in both responders and nonresponders at the end of study (all P values are ≥0.2. Treatment response did not affect the incidence of accidental falls. Future studies based on larger sample sizes, and with longer followup, are required to confirm the beneficial effect of PR dalfampridine on standing balance.

  3. Balanced homodyne detection of Bragg microhologramms in photopolymer for data storage

    OpenAIRE

    Guattari, Frédéric; Maire, Guillaume; Contreras, Kevin; Arnaud, Carole; Pauliat, Gilles; Roosen, Gérald; Jradi, Safi; Carre, Christiane

    2007-01-01

    Wavelength multiplexed holographic bit oriented memories are serious competitors for high capacity data storage systems. For data recording, two interfering beams are required whereas one of them should be blocked for readout in previously proposed systems. This makes the system complex. To circumvent this difficulty and make the device simpler, we validated an architecture for such memories in which the same two beams are used for recording and reading out. This balanced homodyne scheme is v...

  4. Single beam write and/or replay of spatial heterodyne holograms

    Science.gov (United States)

    Thomas, Clarence E.; Hanson, Gregory R.

    2007-11-20

    A method of writing a spatially heterodyne hologram having spatially heterodyne fringes includes: passing a single write beam through a spatial light modulator that digitally modulates said single write beam; and focusing the single write beam at a focal plane of a lens to impose a holographic diffraction grating pattern on the photorefractive crystal, the holographic diffraction grating pattern including the spatially heterodyne hologram having spatially heterodyne fringes, wherein only said single write beam is incident on said photorefractive crystal without a reference beam. A method of replaying a spatially heterodyne hologram having spatially heterodyne fringes at a replay angle includes: illuminating a photorefractive crystal having a holographic diffraction grating with a beam from a laser at an illumination angle, the holographic diffraction grating pattern including the spatially heterodyne hologram having spatially heterodyne fringes, wherein a difference between said illumination angle and said replay angle defines a diffraction angle .alpha. that is a function of a plane wave mathematically added to original object wave phase and amplitude data of said spatially heterodyne hologram having spatially heterodyne fringes.

  5. Recording multiple spatially-heterodyned direct to digital holograms in one digital image

    Science.gov (United States)

    Hanson, Gregory R.; Bingham, Philip R.

    2008-03-25

    Systems and methods are described for recording multiple spatially-heterodyned direct to digital holograms in one digital image. A method includes digitally recording, at a first reference beam-object beam angle, a first spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis; Fourier analyzing the recorded first spatially-heterodyned hologram by shifting a first original origin of the recorded first spatially-heterodyned hologram to sit on top of a first spatial-heterodyne carrier frequency defined by the first reference beam-object beam angle; digitally recording, at a second reference beam-object beam angle, a second spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis; Fourier analyzing the recorded second spatially-heterodyned hologram by shifting a second original origin of the recorded second spatially-heterodyned hologram to sit on top of a second spatial-heterodyne carrier frequency defined by the second reference beam-object beam angle; applying a first digital filter to cut off signals around the first original origin and define a first result; performing a first inverse Fourier transform on the first result; applying a second digital filter to cut off signals around the second original origin and define a second result; and performing a second inverse Fourier transform on the second result, wherein the first reference beam-object beam angle is not equal to the second reference beam-object beam angle and a single digital image includes both the first spatially-heterodyned hologram and the second spatially-heterodyned hologram.

  6. Balanced homodyne detection of Bragg microholograms in photopolymer for data storage.

    Science.gov (United States)

    Guattari, Frédéric; Maire, Guillaume; Contreras, Kevin; Arnaud, Carole; Pauliat, Gilles; Roosen, Gérald; Jradi, Safi; Carré, Christiane

    2007-03-01

    Wavelength multiplexed holographic bit oriented memories are serious competitors for high capacity data storage systems. For data recording, two interfering beams are required whereas one of them should be blocked for readout in previously proposed systems. This makes the system complex. To circumvent this difficulty and make the device simpler, we validated an architecture for such memories in which the same two beams are used for recording and reading out. This balanced homodyne scheme is validated by recording holograms in a Lippmann architecture. PMID:19532458

  7. Coherent Optical Transceiver using Circular Polarization-Based Balanced Mixing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Boulder Nonlinear Systems (BNS) proposes to use its electro-optic component and subsystem expertise to transition a patented heterodyne detection scheme previously...

  8. Elevation profile influence at key contractual performance parameters for LDS (Leak Detection Systems) based on compensated volume balance

    Energy Technology Data Exchange (ETDEWEB)

    Liebenberg, Lieb [TRANSNET Pipeline, Durban (South Africa); Bueno, David; Passos, Rafaela [KANOPUS Consulting, Rio de Janeiro, RJ (Brazil)

    2009-07-01

    This paper describes and discusses procedures and correlations to estimate performance parameters for Leak Detection Systems based on Compensation Volume Balance, at the portions not usually covered by international standards (like, API RP 1130). These parameters include: minimum acceptable leakage to be detected, under steady state conditions, based on flow measurement uncertainty, observed for both pipeline head and tail; an actual flow rate uncertainty against the one informed by the flow meter manufacturer documentation; the reference flow rate for steady state conditions; and the sensitivity one may expect for the system against a given probability of false alarms (i.e., the ways to correlate reliability, the main performance parameter as per API RP 1130 and sensitivity, the second one). A question usually not considered is: how the elevation profile may affect some of these parameters. That is the second main objective addressed herein, with actual examples employed in a South African multi product pipeline. (author)

  9. Terahertz multi-heterodyne spectroscopy using laser frequency combs

    CERN Document Server

    Yang, Yang; Hayton, Darren J; Gao, Jian-Rong; Reno, John L; Hu, Qing

    2016-01-01

    Frequency combs based on terahertz quantum cascade lasers feature broadband coverage and high output powers in a compact package, making them an attractive option for broadband spectroscopy. Here, we demonstrate the first multi-heterodyne spectroscopy using two terahertz quantum cascade laser combs. With just 100 $\\mu$s of integration time, we achieve peak signal-to-noise ratios exceeding 60 dB and a spectral coverage greater than 250 GHz centered at 2.8 THz. Even with room-temperature detectors we are able to achieve peak signal-to-noise ratios of 50 dB, and as a proof-of-principle we use these combs to measure the broadband transmission spectrum of etalon samples. Finally, we show that with proper signal processing, it is possible to extend the multi-heterodyne spectroscopy to quantum cascade laser combs operating in pulsed mode, greatly expanding the range of quantum cascade lasers that could be suitable for these techniques.

  10. Self-heterodyne mixing method of two inter-mode beat frequencies for frequency stabilization of a three-mode He-Ne laser

    Directory of Open Access Journals (Sweden)

    Jeongmin Lee

    2012-06-01

    Full Text Available We present a robust self-heterodyne mixing method of two inter-mode beat frequencies suitable for frequency stabilization of a three longitudinal-mode (3-mode He-Ne laser at 633 nm. A high-contrast frequency discrimination signal with a broad locking range of 244 MHz is obtained by using a self-heterodyned double balanced mixer operating at the inter-mode beat frequency of 607 MHz. We show that the central-mode frequency of the 3-mode He-Ne laser could be stabilized to the center of the gain profile with a frequency fluctuation less than ± 5 MHz for more than 12 h.

  11. Magnetostriction strain measurement: heterodyne laser interferometry versus strain gauge technique

    OpenAIRE

    Gorji Ghalamestani, Setareh; Vandevelde, Lieven; J.J. Dirckx, Joris; Melkebeek, Jan

    2013-01-01

    Deformation of the ferromagnetic material, known as magnetostriction, causes vibrations and noise of electrical machines and transformer cores. A setup by using heterodyne laser interferometers has been built to measure the magnetostriction strains as a function of the applied magnetic field. The measurement results on a sample of nonoriented electrical steel are presented in this work. These results are compared with those obtained by using a strain gauge setup. The laser measurements are l...

  12. Towards an Imaging Mid-Infrared Heterodyne Spectrometer

    Science.gov (United States)

    Hewagama, T.; Aslam, S.; Jones, H.; Kostiuk, T.; Villanueva, G.; Roman, P.; Shaw, G. B.; Livengood, T.; Allen, J. E.

    2012-01-01

    We are developing a concept for a compact, low-mass, low-power, mid-infrared (MIR; 5- 12 microns) imaging heterodyne spectrometer that incorporates fiber optic coupling, Quantum Cascade Laser (QCL) local oscillator, photomixer array, and Radio Frequency Software Defined Readout (RFSDR) for spectral analysis. Planetary Decadal Surveys have highlighted the need for miniaturized, robust, low-mass, and minimal power remote sensing technologies for flight missions. The drive for miniaturization of remote sensing spectroscopy and radiometry techniques has been a continuing process. The advent of MIR fibers, and MEMS techniques for producing waveguides has proven to be an important recent advancement for miniaturization of infrared spectrometers. In conjunction with well-established photonics techniques, the miniaturization of spectrometers is transitioning from classic free space optical systems to waveguide/fiber-based structures for light transport and producing interference effects. By their very nature, these new devices are compact and lightweight. Mercury-Cadmium-Telluride (MCT) and Quantum Well Infrared Photodiodes (QWIP) arrays for heterodyne applications are also being developed. Bulky electronics is another barrier that precluded the extension of heterodyne systems into imaging applications, and our RFSDR will address this aspect.

  13. New sub-millimeter heterodyne observations of CO and HCN in Titan's atmosphere with the APEX Swedish Heterodyne Facility Instrument

    CERN Document Server

    Rengel, M; Hartogh, P

    2010-01-01

    The origin of the atmosphere of the largest moon of Saturn, Titan, is poorly understood and its chemistry is rather complicated. Ground-based millimeter/sub-millimeter heterodyne spectroscopy resolves line shapes sufficiently to determine information in Titan's atmospheric composition (on vertical profiles and isotopic ratios). We test the capabilities of the Swedish Heterodyne Facility Instrument (SHFI), Receiver APEX-1, together with the Atacama Pathfinder EXperiment APEX 12-m telescope for Titan's atmospheric observations. In particular we present sub-millimeter observations of the CO(2-1) and HCN(3-2) lines of the Titan stratosphere with APEX, and with SHFI taken during the Science Verification (SV) instrument phase on March and June 2008. With the help of appropriate radiative transfer calculations we investigate the possibility to constrain the chemical concentrations and optimize the performance of the APEX-1 instrument for inferring vertical profiles of molecular components of the atmosphere of Titan.

  14. Compensated Mass Balance Method For Oil Pipeline Leakage Detection using SCADA

    Directory of Open Access Journals (Sweden)

    Mohamed Zaid A. Karim

    2015-12-01

    Full Text Available Having extracting oil from reservoir below the ground surface, and after processing, the products are transported through a network of oil pipelines to oil terminals. Thus, oil pipelines play a major role of the economic structure. However, oil pipelines could be subjected to damage due to many reasons like (i Pipeline corrosion or wear, (ii Operation outside the design limits, (iii Unintentional third-party damage and (iv Intentional damage. As a result of this damage, oil would leak from pipelines, which leads to loss of life and property, cost of lost product and line downtime, environmental cleanup cost, possible fines and legal suits. The biggest challenge in this industry is to come up with a pipeline leak detection method that will accurately detect leaks in a timely fashion. There are several methods which lead to detection of pipeline leakage. In most Yemeni oil fields pipeline leakage is detected by fiber optics sensing method which is expensive or by visual inspection using experienced personnel who walk along a pipeline, looking for unusual patterns near the pipeline. In this paper, we are going to implement a different and cost effective method using Supervisory Control and Data Acquisition (SCADA system. Simulation has been performed using Rockwell Automation Software Products. The results so obtained are presented and discussed.

  15. On-chip detection performed by amorphous silicon balanced photosensor for lab-on chip application

    Directory of Open Access Journals (Sweden)

    G. de Cesare

    2015-03-01

    The experiments have been carried out measuring the differential current in several conditions. All the experiments have been executed under a large background light intensity to reproduce realistic operating conditions in biomedical applications. We have found that the proposed device is able to detect the presence or absence of water flow in the channel and the presence of fluorescent marker. In particular, under identical channel conditions the differential current is at least a factor 60 lower that the current flowing in each diode.

  16. Balancing Frequencies and Fault Detection in the In-Parameter-Order Algorithm

    Institute of Scientific and Technical Information of China (English)

    高世伟; 吕江花; 杜冰磊; Charles J. Colbourn; 马世龙

    2015-01-01

    The In-Parameter-Order (IPO) algorithm is a widely used strategy for the construction of software test suites for combinatorial testing (CT) whose goal is to reveal faults triggered by interactions among parameters. Variants of IPO have been shown to produce test suites within reasonable amounts of time that are often not much larger than the smallest test suites known. When an entire test suite is executed, all faults that arise from t-way interactions for some fixed t are surely found. However, when tests are executed one at a time, it is desirable to detect a fault as early as possible so that it can be repaired. The basic IPO strategies of horizontal and vertical growth address test suite size, but not the early detection of faults. In this paper, the growth strategies in IPO are modified to attempt to evenly distribute the values of each parameter across the tests. Together with a reordering strategy that we add, this modification to IPO improves the rate of fault detection dramatically (improved by 31% on average). Moreover, our modifications always reduce generation time (2 times faster on average) and in some cases also reduce test suite size.

  17. On the Performance of Multihop Heterodyne FSO Systems With Pointing Errors

    KAUST Repository

    Zedini, Emna

    2015-03-30

    This paper reports the end-to-end performance analysis of a multihop free-space optical system with amplify-and-forward (AF) channel-state-information (CSI)-assisted or fixed-gain relays using heterodyne detection over Gamma–Gamma turbulence fading with pointing error impairments. In particular, we derive new closed-form results for the average bit error rate (BER) of a variety of binary modulation schemes and the ergodic capacity in terms of the Meijer\\'s G function. We then offer new accurate asymptotic results for the average BER and the ergodic capacity at high SNR values in terms of simple elementary functions. For the capacity, novel asymptotic results at low and high average SNR regimes are also obtained via an alternative moments-based approach. All analytical results are verified via computer-based Monte-Carlo simulations.

  18. Toward a nonlinearity model for a heterodyne interferometer: not based on double-frequency mixing.

    Science.gov (United States)

    Hu, Pengcheng; Bai, Yang; Zhao, Jinlong; Wu, Guolong; Tan, Jiubin

    2015-10-01

    Residual periodic errors detected in picometer-level heterodyne interferometers cannot be explained by the model based on double-frequency mixing. A new model is established and proposed in this paper for analysis of these errors. The multi-order Doppler frequency shift ghost beams from measurement beam itself are involved in final interference leading to multi-order periodic errors, whether or not frequency-mixing originating from the two incident beams occurs. For model validation, a novel setup free from double-frequency mixing is constructed. The analyzed measurement signal shows that phase mixing of measurement beam itself can lead to multi-order periodic errors ranging from tens of picometers to one nanometer. PMID:26480108

  19. AMiBA: Broadband Heterodyne CMB Interferometry

    OpenAIRE

    Chen, Ming-Tang; Li, Chao-Te; Hwang, Yuh-Jing; Jiang, Homin; Altamirano, Pablo; Chang, Chia-Hao; Chang, Shu-Hao; Chang, Su-Wei; Chiueh, Tzi-Dar; Chu, Tah-Hsiung; Han, Chih-Chiang; Huang, Yau-De; Kesteven, Michael; Kubo, Derek; Martin-Cocher, Pierre

    2009-01-01

    The Y. T. Lee Array for Microwave Background (AMiBA) has reported the first science results on the detection of galaxy clusters via the Sunyaev Zel'dovich effect. The science objectives required small reflectors in order to sample large scale structures (20') while interferometry provided modest resolutions (2'). With these constraints, we designed for the best sensitivity by utilizing the maximum possible continuum bandwidth matched to the atmospheric window at 86-102GHz, with dual polarizat...

  20. Simple signal-to-signal beat interference cancellation receiver based on balanced detection for a single-sideband optical OFDM signal with a reduced guard band.

    Science.gov (United States)

    Ma, Jianxin

    2013-11-01

    A simple signal-to-signal beat interference cancellation receiver based on balanced detection (ICRBD) with an interleaver, a 2×2 three-decibel optical coupler, and a balanced photodiode pair is proposed for a single-sideband optical orthogonal frequency division multiplexing (SSB-OOFDM) signal with a reduced guard band (GB). Simulation demonstration of the ICRBD for a 40 Gbit/s 16-QAM SSB-OOFDM signal with a reduced GB was achieved successfully. PMID:24177087

  1. AMiBA: Broadband Heterodyne CMB Interferometry

    CERN Document Server

    Chen, Ming-Tang; Hwang, Yuh-Jing; Jiang, Homin; Altamirano, Pablo; Chang, Chia-Hao; Chang, Shu-Hao; Chang, Su-Wei; Chiueh, Tzi-Dar; Chu, Tah-Hsiung; Han, Chih-Chiang; Huang, Yau-De; Kesteven, Michael; Kubo, Derek; Martin-Cocher, Pierre; Oshiro, Peter; Raffin, Philippe; Wei, Tashun; Wang, Huei; Wilson, Warwick; Ho, Paul T P; Huang, Chih-Wei; Koch, Patrick; Liao, Yu-Wei; Lin, Kai-Yang; Liu, Guo-Chin; Molnar, Sandor M; Nishioka, Hiroaki; Umetsu, Keiichi; Wang, Fu-Cheng; Wu, Jiun-Huei Proty

    2009-01-01

    The Y. T. Lee Array for Microwave Background (AMiBA) has reported the first science results on the detection of galaxy clusters via the Sunyaev Zel'dovich effect. The science objectives required small reflectors in order to sample large scale structures (20') while interferometry provided modest resolutions (2'). With these constraints, we designed for the best sensitivity by utilizing the maximum possible continuum bandwidth matched to the atmospheric window at 86-102GHz, with dual polarizations. A novel wide-band analog correlator was designed that is easily expandable for more interferometer elements. MMIC technology was used throughout as much as possible in order to miniaturize the components and to enhance mass production. These designs will find application in other upcoming astronomy projects. AMiBA is now in operations since 2006, and we are in the process to expand the array from 7 to 13 elements.

  2. Terahertz heterodyne spectrometer using a quantum cascade laser

    OpenAIRE

    Ren, Y; Hovenier, J.N.; Higgins, R.; Gao, J.R.; Klapwijk, T. M.; Shi, S. C.; Bell, A; Klein, B; Williams, B. S.; Kumar, S.; Q. Hu; Reno, J. L.

    2010-01-01

    A terahertz (THz) heterodyne spectrometer is demonstrated based on a quantum cascade laser(QCL) as a local oscillator (LO) and an NbN hot electron bolometer as a mixer, and it is used to measure high-resolution molecular spectral lines of methanol (CH_3OH) between 2.913–2.918 THz. The spectral lines are taken from a gas cell containing methanol gas and using a single-mode QCL at 2.9156 THz as an LO, which is operated in the free running mode. By increasing the pressure of the gas, line broade...

  3. Competition of modes in an optically heterodyned acoustooptic generator

    International Nuclear Information System (INIS)

    An acoustooptic generator in which the feedback signal is produced using optical heterodyning is studied theoretically and experimentally. The development of oscillations in this system is analysed by computer simulations. It is shown that the competition of modes caused by nonlinearity of the acoustooptic interaction can result in the degeneration of the generation spectrum and the establishment of a single-mode regime. The dependence of the generator linewidth on the parameters of the system is studied. (laser applications and other topics in quantum electronics)

  4. Development of a heterodyne micro-wave reflectometer with ultra-fast sweeping. The study of the plasma turbulence influence on the measurements of electron density profile

    International Nuclear Information System (INIS)

    The density profile of the fusion plasmas can be investigated by the reflectometry diagnostics. The measurement principle is based on the radar techniques which calculate the phase shift of a millimeter wave propagating into the plasma and reflected at a cut-off layer. However, this propagation is perturbed by the plasma turbulence. These phenomena affect the phase delay measurement by not well understood a process. In this work we have tried to find the mechanisms and origin of the turbulence which is responsible for the phase disturbance. We point out the role of collisionality and plasma radiation in controlling the instability and also, demonstrate that the phase delay of the probing wave is very sensitive to the plasma MHD phenomena and is less affected by the micro-turbulence. The second part of this work is the development and the use of a new heterodyne reflectometer. The principal characteristics are given. Its heterodyne detection allows the separation of phase and amplitude information from the detected signal and then to study their contribution to the mechanism of signal perturbation. The use of this reflectometer allows us to point out the following points: - a high dynamic availability, required by the large amplitude drops, often greater than 30 db; - fast sweep operation requirement to 'freeze' the plasma turbulence; - multiple reflection effects which modulate the amplitude and phase of the probing wave if they are not suppressed by filtering the detected signal; - very good localisation of the measurement (of the order of millimeter). The heterodyne reflectometer developed during this work offers several advantages of different distinct reflectometry techniques (fast sweep, absolute and differential phase measurements, heterodyne detection). It could be developed to work over higher frequency range so as to measure density profile over larger radial extension with very high performances. (author)

  5. Millimeter-Wave Heterodyne Six-Port Receiver: New Implementation and Demodulation Results

    Institute of Scientific and Technical Information of China (English)

    D Hammou; E. Moldovan; S.O. Tatu

    2011-01-01

    This paper presents a new implementation of a millimeter-wave heterodyne receiver based on six-port technology. The six-port model is implemented in Advanced Design System (ADS) using S-parameter measurements for realistic advanced simulation of a short-range 60 GHz wireless link. Millimeter-wave frequency conversion is performed using a six-port down-converter. The second frequency conversion is performed using conventional means because of low IF. A comparison between the proposed receiver and a conventional balanced millimeter-wave mixer shows that the proposed receiver improves conversion loss and I/Q phase stability over the local oscillator (LO) and RF power ranges. The results of demodulating a V-band quadrature phase-shift keying (QPSK) signal at a high data rate of 100 Mb/s-1 Gb/s are discussed. The results of a bit error rate (BER) and error vector magnitude (EVM) analysis prove that the proposed architecture can be successfully used for wireless link transmission up to 10 m.

  6. Micro-Gal laser absolute gravimeter based on high precision heterodyne interferometer

    Institute of Scientific and Technical Information of China (English)

    Zhiping Zhang; Zhaogu Cheng; Zhaoyu Qin; Jianqiang Zhu

    2007-01-01

    A micro-Gal absolute gravimeter based on high-precision and high-stability heterodyne interferometer is presented. The distance measuring technology of the gravimeter is studied in detail. The experimental results of distance measuring for a free-falling motion show that the high-precision heterodyne interferometer described in this paper can meet the demand of a micro-Gal absolute gravimeter with relative uncertainty of 6.4 × 10-9. Moreover, the heterodyne interferometer is more stable than the Mach-Zehnder interferometer (MZI) which is widely used in present absolute gravimeters.

  7. Electronic heterodyne recording and processing of optical holograms using phase modulated reference waves

    Science.gov (United States)

    Decker, A. J.; Pao, Y.-H.; Claspy, P. C.

    1978-01-01

    The use of a phase-modulated reference wave for the electronic heterodyne recording and processing of a hologram is described. Heterodyne recording is used to eliminate the self-interference terms of a hologram and to create a Leith-Upatnieks hologram with coaxial object and reference waves. Phase modulation is also shown to be the foundation of a multiple-view hologram system. When combined with hologram scale transformations, heterodyne recording is the key to general optical processing. Spatial filtering is treated as an example.

  8. A high-speed 12-layer two-dimensional bar code detection system with wideband photodetection amplifier and balanced raster scanner

    Science.gov (United States)

    Wakaumi, Hiroo; Ajiki, Hiroshi

    1998-12-01

    A high-speed 12-layer 2D bar-code detection system (BCDS) consisting of a photodetection amplifier with an amplification-type current-voltage converter and a balanced raster scanner combined with the complementary light emission drive method for laser diodes, has been developed in order to provide both a high effective scanning speed and multi-layer bar-code detection. This BCDS performs 1,250 scan/s, which is two and a half times the scanning speed of a conventional bar-code detection system. A new theoretical modulation model that gives an accurate model for laser scanning beam traces obtained by the balanced raster scanner is proposed. This model allows an optimum BCDS to be designed easily.

  9. Digital Phase Meter for a Laser Heterodyne Interferometer

    Science.gov (United States)

    Loya, Frank

    2008-01-01

    The Digital Phase Meter is based on a modified phase-locked loop. When phase alignment between the reference input and the phase-shifted metrological input is achieved, the loop locks and the phase shift of the digital phase shifter equals the phase difference that one seeks to measure. This digital phase meter is being developed for incorporation into a laser heterodyne interferometer in a metrological apparatus, but could also be adapted to other uses. Relative to prior phase meters of similar capability, including digital ones, this digital phase meter is smaller, less complex, and less expensive. The phase meter has been constructed and tested in the form of a field-programmable gate array (FPGA).

  10. A Monolithic, Non-Field-Widened Spatial Heterodyne Spectrometer for Solar System Exploration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this project is to produce a monolithic Spatial Heterodyne Spectrometer (a Fourier Transform Interferometer) for use in Solar System exploration. In...

  11. Determination of azimuthal anchoring strength in twisted nematic liquid crystal cells using heterodyne polarimeter.

    Science.gov (United States)

    Yu, Tsung-Chih; Lo, Yu-Lung; Huang, Rei-Rong

    2010-09-27

    Two external-field-free methods are presented for measuring the azimuthal anchoring strength in twisted nematic liquid crystal (TNLC) cells. For asymmetrical TNLC samples, the twist angle is derived from the phase of the detected signal in a phase-sensitive heterodyne polarimeter and is then used to calculate the weak anchoring strength directly. The measurement resolution which is found to be about 0.01 μJ/m(2) makes the present method sensitive enough for the LC-based bio-sensing application. Using the proposed method, the weak azimuthal anchoring strength of a composite liquid crystal mixture (40% LCT-061153 + 60% MJO-42761) in contact with a plasma-alignment layer is found to be 7.19 μJ/m(2). For symmetrical TNLC samples, the liquid crystals are injected into a wedge cell, and the two-dimensional distributions of the twist angle and cell gap are extracted from the detected phase distribution using a genetic algorithm (GA). The azimuthal anchoring strength is then obtained by applying a fitting technique to the twist angle vs. cell gap curve. Utilizing the proposed approach, it is shown that the strong anchoring strength between a rubbed polyimide (PI) alignment layer and E7 liquid crystal is around 160 μJ/m(2) while that between a rubbed PI alignment layer and MLC-7023 liquid crystal is approximately 32 μJ/m(2). PMID:20941014

  12. Heterodyne pump probe measurements of nonlinear dynamics in an indium phosphide photonic crystal cavity

    DEFF Research Database (Denmark)

    Heuck, Mikkel; Combrié, S.; Lehoucq, G.;

    2013-01-01

    Using a sensitive two-color heterodyne pump-probe technique, we investigate the carrier dynamics of an InP photonic crystal nanocavity. The heterodyne technique provides unambiguous results for all wavelength configurations, including the degenerate case, which cannot be investigated with the...... widely used homodyne technique. A model based on coupled mode theory including two carrier distributions is introduced to account for the relaxation dynamics, which is assumed to be governed by both diffusion and recombination....

  13. High resolution heterodyne interferometer based on time-to-digital converter.

    Science.gov (United States)

    Wang, Fei; Long, Zhangcai; Zhang, Bin; Zhao, Meirong

    2012-04-01

    A new heterodyne interferometer is presented, which adopts time-to-digital converter (TDC) measuring the time intervals of zero crossings of heterodyne signal for phase demodulation. Thanks to the 0.1 ns time resolution of TDC and linear phase demodulation, it can achieve high resolution and avoids nonlinear measuring distortion in other indirect high precise phase demodulation methods, such as pulse width modulation (PWM) and in-phase∕quadrature (I∕Q) method. PMID:22559581

  14. Greenhouse Gas Concentration Data Recovery Algorithm for a Low Cost, Laser Heterodyne Radiometer

    Science.gov (United States)

    Miller, J. H.; Melroy, H.; Ott, L.; McLinden, M. L.; Holben, B. N.; Wilson, E. L.

    2012-12-01

    The goal of a coordinated effort between groups at GWU and NASA GSFC is the development of a low-cost, global, surface instrument network that continuously monitors three key carbon cycle gases in the atmospheric column: carbon dioxide (CO2), methane (CH4), carbon monoxide (CO), as well as oxygen (O2) for atmospheric pressure profiles. The network will implement a low-cost, miniaturized, laser heterodyne radiometer (mini-LHR) that has recently been developed at NASA Goddard Space Flight Center. This mini-LHR is designed to operate in tandem with the passive aerosol sensor currently used in AERONET (a well established network of more than 450 ground aerosol monitoring instruments worldwide), and could be rapidly deployed into this established global network. Laser heterodyne radiometry is a well-established technique for detecting weak signals that was adapted from radio receiver technology. Here, a weak light signal, that has undergone absorption by atmospheric components, is mixed with light from a distributed feedback (DFB) telecommunications laser on a single-mode optical fiber. The RF component of the signal is detected on a fast photoreceiver. Scanning the laser through an absorption feature in the infrared, results in a scanned heterodyne signal in the RF. Deconvolution of this signal through the retrieval algorithm allows for the extraction of altitude contributions to the column signal. The retrieval algorithm is based on a spectral simulation program, SpecSyn, developed at GWU for high-resolution infrared spectroscopies. Variations in pressure, temperature, composition, and refractive index through the atmosphere; that are all functions of latitude, longitude, time of day, altitude, etc.; are modeled using algorithms developed in the MODTRAN program developed in part by the US Air Force Research Laboratory. In these calculations the atmosphere is modeled as a series of spherically symmetric shells with boundaries specified at defined altitudes. Temperature

  15. Structure of multiphoton quantum optics. II. Bipartite systems, physical processes, and heterodyne squeezed states

    International Nuclear Information System (INIS)

    Extending the scheme developed for a single mode of the electromagnetic field in the preceding paper [F. Dell'Anno, S. De Siena, and F. Illuminati, Phys. Rev. A 69, 033812 (2004)], we introduce two-mode nonlinear canonical transformations depending on two heterodyne mixing angles. They are defined in terms of Hermitian nonlinear functions that realize heterodyne superpositions of conjugate quadratures of bipartite systems. The canonical transformations diagonalize a class of Hamiltonians describing nondegenerate and degenerate multiphoton processes. We determine the coherent states associated with the canonical transformations, which generalize the nondegenerate two-photon squeezed states. Such heterodyne multiphoton squeezed states are defined as the simultaneous eigenstates of the transformed, coupled annihilation operators. They are generated by nonlinear unitary evolutions acting on two-mode squeezed states. They are non-Gaussian, highly nonclassical, entangled states. For a quadratic nonlinearity the heterodyne multiphoton squeezed states define two-mode cubic phase states. The statistical properties of these states can be widely adjusted by tuning the heterodyne mixing angles, the phases of the nonlinear couplings, as well as the strength of the nonlinearity. For quadratic nonlinearity, we study the higher-order contributions to the susceptibility in nonlinear media and we suggest possible experimental realizations of multiphoton conversion processes generating the cubic-phase heterodyne squeezed states

  16. The stray capacitance effect in Kelvin probe force microscopy using FM, AM and heterodyne AM modes

    International Nuclear Information System (INIS)

    The effect of stray capacitance on potential measurements was investigated using Kelvin probe force microscopy (KPFM) at room temperature under ultra-high vacuum (UHV). The stray capacitance effect was explored in three modes, including frequency modulation (FM), amplitude modulation (AM) and heterodyne amplitude modulation (heterodyne AM). We showed theoretically that the distance-dependence of the modulated electrostatic force in AM-KPFM is significantly weaker than in FM- and heterodyne AM-KPFMs and that the stray capacitance of the cantilever, which seriously influences the potential measurements in AM-KPFM, was almost completely eliminated in FM- and heterodyne AM-KPFMs. We experimentally confirmed that the contact potential difference (CPD) in AM-KPFM, which compensates the electrostatic force between the tip and the surface, was significantly larger than in FM- and heterodyne AM-KPFMs due to the stray capacitance effect. We also compared the atomic scale corrugations in the local contact potential difference (LCPD) among the three modes on the surface of Si(111)-7 × 7 finding that the LCPD corrugation in AM-KPFM was significantly weaker than in FM- and heterodyne AM-KPFMs under low AC bias voltage conditions. The very weak LCPD corrugation in AM-KPFM was attributed to the artefact induced by topographic feedback. (paper)

  17. Structure of multiphoton quantum optics. II. Bipartite systems, physical processes, and heterodyne squeezed states

    Science.gov (United States)

    dell'Anno, Fabio; de Siena, Silvio; Illuminati, Fabrizio

    2004-03-01

    Extending the scheme developed for a single mode of the electromagnetic field in the preceding paper [F. Dell’Anno, S. De Siena, and F. Illuminati, Phys. Rev. A 69, 033812 (2004)], we introduce two-mode nonlinear canonical transformations depending on two heterodyne mixing angles. They are defined in terms of Hermitian nonlinear functions that realize heterodyne superpositions of conjugate quadratures of bipartite systems. The canonical transformations diagonalize a class of Hamiltonians describing nondegenerate and degenerate multiphoton processes. We determine the coherent states associated with the canonical transformations, which generalize the nondegenerate two-photon squeezed states. Such heterodyne multiphoton squeezed states are defined as the simultaneous eigenstates of the transformed, coupled annihilation operators. They are generated by nonlinear unitary evolutions acting on two-mode squeezed states. They are non-Gaussian, highly nonclassical, entangled states. For a quadratic nonlinearity the heterodyne multiphoton squeezed states define two-mode cubic phase states. The statistical properties of these states can be widely adjusted by tuning the heterodyne mixing angles, the phases of the nonlinear couplings, as well as the strength of the nonlinearity. For quadratic nonlinearity, we study the higher-order contributions to the susceptibility in nonlinear media and we suggest possible experimental realizations of multiphoton conversion processes generating the cubic-phase heterodyne squeezed states.

  18. Heterodyne stabilization as a possible laser frequency stabilization technique for LISA

    Science.gov (United States)

    Eichholz, Johannes

    The Laser Interferometer Space Antenna is a joint NASA/ESA mission aimed at the detection of gravitational wave radiation in the frequency range from 30 uHz to 0.1 Hz. LISA uses a modified Michelson interferometer setup consisting of three identical spacecraft, arranged in an equilateral triangular constellation. It measures the differential length changes of the 5 · 109 m long interferometer arms between free-floating proof masses housed within each spacecraft. Laser pre-stabilization is required in conjunction with Time-Delay Interferometry data post-processing to monitor the armlength changes with picometer precision. A modulation/demodulation technique to stabilize the frequency of the lasers to an optical reference cavity has been proposed for a long time, but it requires several additional optical components and would need to be built as a separate system. Using a different sensing tech-nique, heterodyne interferometry, we propose a modified stabilization scheme, which similarly transfers the stability of an optical reference cavity to the laser frequency. It only uses com-ponents that are already available in the LISA assembly and can easily be integrated into the optical bench design. A similar stabilization scheme is going to be used in LISA Pathfinder. We will discuss this technique in detail and present initial experimental results, as well as predicted performances on the LISA bench.

  19. A laser-heterodyne bunch length monitor for the SLC interaction point

    International Nuclear Information System (INIS)

    Since 1996, the transverse beam sizes at the SLC interaction point (IP) can be determined with a 'laser wire', by detecting the rate of Compton-scattered photons as a function of the beam-laser separation in space. Nominal laser parameters are: 350 nm wavelength, 2 mJ energy per pulse, 40 Hz repetition rate, and 150 ps FWHM pulse length. The laser system is presently being modified to enable measurements of the longitudinal beam profile. For this purpose, two laser pulses of slightly different frequency are superimposed, which creates a travelling fringe pattern and, thereby, introduces a bunch-to-bunch variation of the Compton rate. The magnitude of this variation depends on the beat wavelength and on the Fourier transform of the longitudinal distribution. This laser heterodyne technique is implemented by adding a 1-km long optical fibre at the laser oscillator output, which produces a linearly chirped laser pulse with 4.5-A linewidth and 60-ps FWHM pulse length. Also, the pulse is amplified in a regenerative amplifier and tripled with two nonlinear crystals. Then a Michelson interferometer spatially overlaps two split chirped pulses, which are temporally shifted with respect to each other, generating a quasi-sinusoidal adjustable fringe pattern. This laser pulse is then transported to the Interaction Point

  20. A laser-heterodyne bunch length monitor for the SLC interaction point

    Energy Technology Data Exchange (ETDEWEB)

    Kotseroglou, T.; Alley, R.; Jobe, K. [and others

    1997-05-01

    Since 1996, the transverse beam sizes at the SLC interaction point (IP) can be determined with a `laser wire`, by detecting the rate of Compton-scattered photons as a function of the beam-laser separation in space. Nominal laser parameters are: 350 nm wavelength, 2 mJ energy per pulse, 40 Hz repetition rate, and 150 ps FWHM pulse length. The laser system is presently being modified to enable measurements of the longitudinal beam profile. For this purpose, two laser pulses of slightly different frequency are superimposed, which creates a travelling fringe pattern and, thereby, introduces a bunch-to-bunch variation of the Compton rate. The magnitude of this variation depends on the beat wavelength and on the Fourier transform of the longitudinal distribution. This laser heterodyne technique is implemented by adding a 1-km long optical fibre at the laser oscillator output, which produces a linearly chirped laser pulse with 4.5-A linewidth and 60-ps FWHM pulse length. Also, the pulse is amplified in a regenerative amplifier and tripled with two nonlinear crystals. Then a Michelson interferometer spatially overlaps two split chirped pulses, which are temporally shifted with respect to each other, generating a quasi-sinusoidal adjustable fringe pattern. This laser pulse is then transported to the Interaction Point.

  1. Validity, Responsiveness, Minimal Detectable Change, and Minimal Clinically Important Change of "Pediatric Balance Scale" in Children with Cerebral Palsy

    Science.gov (United States)

    Chen, Chia-ling; Shen, I-hsuan; Chen, Chung-yao; Wu, Ching-yi; Liu, Wen-Yu; Chung, Chia-ying

    2013-01-01

    This study examined criterion-related validity and clinimetric properties of the pediatric balance scale ("PBS") in children with cerebral palsy (CP). Forty-five children with CP (age range: 19-77 months) and their parents participated in this study. At baseline and at follow up, Pearson correlation coefficients were used to determine…

  2. Sensitivity analysis of periodic errors in heterodyne interferometry

    International Nuclear Information System (INIS)

    Periodic errors in heterodyne displacement measuring interferometry occur due to frequency mixing in the interferometer. These nonlinearities are typically characterized as first- and second-order periodic errors which cause a cyclical (non-cumulative) variation in the reported displacement about the true value. This study implements an existing analytical periodic error model in order to identify sensitivities of the first- and second-order periodic errors to the input parameters, including rotational misalignments of the polarizing beam splitter and mixing polarizer, non-orthogonality of the two laser frequencies, ellipticity in the polarizations of the two laser beams, and different transmission coefficients in the polarizing beam splitter. A local sensitivity analysis is first conducted to examine the sensitivities of the periodic errors with respect to each input parameter about the nominal input values. Next, a variance-based approach is used to study the global sensitivities of the periodic errors by calculating the Sobol' sensitivity indices using Monte Carlo simulation. The effect of variation in the input uncertainty on the computed sensitivity indices is examined. It is seen that the first-order periodic error is highly sensitive to non-orthogonality of the two linearly polarized laser frequencies, while the second-order error is most sensitive to the rotational misalignment between the laser beams and the polarizing beam splitter. A particle swarm optimization technique is finally used to predict the possible setup imperfections based on experimentally generated values for periodic errors

  3. A submillimeter heterodyne receiver and its application in astronomy

    International Nuclear Information System (INIS)

    A submm heterodyne receiver for astronomical observations has been developed which operates in the frequency range between 460 and 500 GHz. An InSb hot electron bolometer is used as the mixing element. The local oscillator power is obtained by doubling the frequency of a backward wave oscillator (B.W.O.). The sideband noise of the B.W.O. has appeared to be sufficiently weak to allow its use in combination with an InSb mixer. A method of measuring the matching of the mixer to the waveguide is described and some results of measurements of B.W.O. noise are given. A general description is presented of Gaussian beam theory and this is applied to the design of the receiver optics. Particular attention is given to the coupling between the receiver and the telescope. To prevent the usually troublesome effects of standing waves between the receiver and the telescope a circular polarizer can be applied. A review is given of different types of such polarizers as presently used in the optical and microwave regimes, with a view to their application in the submm range. Two types of circular polarizers were constructed and results of measurements on these are given. The final chapter describes the observation of the rotational CO J = 4→3 transition at 461 GHz in the Kleinman Low nebula. From a combination of this measurement with others, lower bounds for the gas kinetic temperature and column density of the shocked gas in this region are derived. (Auth.)

  4. Comparative study of by near-field heterodyne transient grating and continuously variable spatial frequency transient grating methods for measurements of terahertz reflection responses

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, H; Katayama, K [Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo, Tokyo 112-8551 (Japan); Shen, Q; Toyoda, T [Department of Applied Physics and Chemistry, University of Electro-Communications, 1-5-1 Chofugaoka Chofu, Tokyo 182-8585 (Japan); Nelson, K A, E-mail: kkata@kc.chuo-u.ac.j [Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139 (United States)

    2010-03-01

    We measured terahertz reflection responses utilizing a propagating phonon polariton wave, which was generated and detected by two different methods: the near-field heterodyne transient grating and the continuously variable spatial frequency transient grating method. The obtained results were compared for the purpose of clarifying which of both methods is better for measurements of terahertz reflection responses. The phonon polariton wave is propagated and reflected at a ferroelectric crystal edge. From the viewpoint of the separation between the excited and reflected phonon polariton waves, the latter method is better for measurements of reflection responses.

  5. Mode beating and heterodyning of monolithically integrated semiconductor ring lasers

    Science.gov (United States)

    Liu, Chiyu

    Monolithically integrated semiconductor ring lasers (SRLs) are attractive optical sources for optoelectronic integrated circuits (OEICs) because they do not require any feedback elements, do not have parts exposed to external ambient, and can operate in a traveling-wave mode. They are promising candidates for wavelength filtering, unidirectional traveling-wave operation, and multiplexing/demultiplexing applications. Ring lasers can also be used as ultrashort pulse generators using various mode-locking schemes and as active gyro components. However, the SRL is a very complicated dynamic system, which requires more investigations to understand the performance regarding details of the design and fabrication. As a part of NASA-supported project "Monolithically Integrated Semiconductor Ring Laser Gyro for Space Applications", this dissertation research was focused on design and characterization of a novel monolithically integrated rotation sensor based on two large-size independent SRLs. Numerical modeling based on the beam propagation method (BPM) was used to design the fabrication parameters for the single-mode ridge-waveguide ring cavity and directional coupler waveguides. The mode internal coupling in single lateral-mode laser diodes with InGaAs/GaAs material system was investigated by optical experiments and numerical modeling. To gain the understanding of the SRL performance, optical and electrical characterization was performed on fabricated SRLs. Particular emphasis was placed on the study of optical and radio frequency (RF) beating spectra of longitudinal modes of ring lasers. RF measurements provide high accuracy in the diagnosis of laser oscillation parameters by purely electronic means, particularly in the measurement of the group index and its dependence on current and temperature. Theoretical analysis based on the effective index method provides good agreement between the experimental data and numerical calculations. Finally, optical heterodyning spectra

  6. Extending the operating temperature, wavelength and frequency response of HgCdTe heterodyne detectors

    Science.gov (United States)

    Spears, D. L.

    1980-01-01

    Near ideal optical heterodyne performance was obtained at GHz IF frequencies in the 10 micrometer wavelength region with liquid nitrogen cooled HgCdTe photodiodes. Heterodyne NEP's as low as 2.7 x 10 to the minus 20th power W/Hz at 100MHz, 5.4 x 10 to the minus 20th power W/Hz at 1.5 GHz, and 9.4 x 19 to the minus 20th power W/Hz at 3 GHz were achieved. Various physical phenomena which occur within a photodiode and affect heterodyne operation were examined in order to assess the feasibility of extending the operating temperature, wavelength, and frequency response of these HgCdTe photomixers.

  7. Advances in quantum-noise-limited doppler-free optical heterodyne spectroscopy

    International Nuclear Information System (INIS)

    This paper discusses recent advance in optical heterodyne spectroscopy such as extensions to couple tree-level saturation spectroscopy and Doppler-free evanescent wave spectroscopy. Optical heterodyne three-level spectroscopy relies on collinear non-generate FWM processes to transfer an HF modulation from a saturating--AM or FM-- beam to a probe bean (of different wavelength) resonant with a neighboring line. Recently, thanks to HF heterodyne techniques, Doppler-free spectroscopy has been extended to monitoring atoms localized near the surface. An example of this is discussed. Relevant applications of the example techniques may concern as diagnostics of optically thick media as an analysis of interaction between gas-phase atoms and surface, notably atom-wall collisions and modification of the spontaneous emission characteristics

  8. A dual-heterodyne laser interferometer for simultaneous measurement of linear and angular displacements

    Science.gov (United States)

    Yan, Hao; Duan, Hui-Zong; Li, Lin-Tao; Liang, Yu-Rong; Luo, Jun; Yeh, Hsien-Chi

    2015-12-01

    Picometer laser interferometry is an essential tool for ultra-precision measurements in frontier scientific research and advanced manufacturing. In this paper, we present a dual-heterodyne laser interferometer for simultaneously measuring linear and angular displacements with resolutions of picometer and nanoradian, respectively. The phase measurement method is based on cross-correlation analysis and realized by a PXI-bus data acquisition system. By implementing a dual-heterodyne interferometer with a highly symmetric optical configuration, low frequency noises caused by the environmental fluctuations can be suppressed to very low levels via common-mode noise rejection. Experimental results for the dual-heterodyne interferometer configuration presented demonstrate that the noise levels of the linear and angular displacement measurements are approximately 1 pm/Hz1/2 and 0.5 nrad/Hz1/2 at 1 Hz.

  9. Structure of multiphoton quantum optics. II. Bipartite systems, physical processes, and heterodyne squeezed states

    CERN Document Server

    Dell'Anno, F; Illuminati, F; Anno, Fabio Dell'; Siena, Silvio De; Illuminati, Fabrizio

    2004-01-01

    Extending the scheme developed for a single mode of the electromagnetic field in the preceding paper ``Structure of multiphoton quantum optics. I. Canonical formalism and homodyne squeezed states'', we introduce two-mode nonlinear canonical transformations depending on two heterodyne mixing angles. They are defined in terms of hermitian nonlinear functions that realize heterodyne superpositions of conjugate quadratures of bipartite systems. The canonical transformations diagonalize a class of Hamiltonians describing non degenerate and degenerate multiphoton processes. We determine the coherent states associated to the canonical transformations, which generalize the non degenerate two--photon squeezed states. Such heterodyne multiphoton squeezed are defined as the simultaneous eigenstates of the transformed, coupled annihilation operators. They are generated by nonlinear unitary evolutions acting on two-mode squeezed states. They are non Gaussian, highly non classical, entangled states. For a quadratic nonline...

  10. Usefulness of the infrared heterodyne radiometer in remote sensing of atmospheric pollutants.

    Science.gov (United States)

    Menzies, R. T.; Shumate, M. S.

    1971-01-01

    The application of narrow-band optical receivers to the problem of sensing atmospheric pollution is discussed. The emission/absorption lines of many major atmospheric pollutant molecules overlap the operating frequency bands of CO2 laser and CO laser heterodyne receivers. Several remote pollution sensing systems which are based upon utilization of these spectral overlaps are described, and an analysis of their potential is presented. The possibility of using other lasers (e.g.: the PbSnTe tunable diode laser) as local oscillators is also considered. Results of laboratory experiments with a CO2 laser heterodyne radiometer are presented.

  11. Methods, compositions and kits for imaging cells and tissues using nanoparticles and spatial frequency heterodyne imaging

    Energy Technology Data Exchange (ETDEWEB)

    Rose-Petruck, Christoph; Wands, Jack R.; Rand, Danielle; Derdak, Zoltan; Ortiz, Vivian

    2016-04-19

    Methods, compositions, systems, devices and kits are provided herein for preparing and using a nanoparticle composition and spatial frequency heterodyne imaging for visualizing cells or tissues. In various embodiments, the nanoparticle composition includes at least one of: a nanoparticle, a polymer layer, and a binding agent, such that the polymer layer coats the nanoparticle and is for example a polyethylene glycol, a polyelectrolyte, an anionic polymer, or a cationic polymer, and such that the binding agent that specifically binds the cells or the tissue. Methods, compositions, systems, devices and kits are provided for identifying potential therapeutic agents in a model using the nanoparticle composition and spatial frequency heterodyne imaging.

  12. Application of a heterodyne laser system to determine parameters of turbulent atmosphere

    International Nuclear Information System (INIS)

    The use of a heterodyne laser system in atmospheric measurements has been proposed. The continuous registration of optical phase variations of radiation propagating in the atmospheric channel has been carried out. From recorded data, the integral characteristics of a turbulence state in the radiation propagation channel are obtained.

  13. Auto-digital gain balancing: a new detection scheme for high-speed chemical species tomography of minor constituents

    International Nuclear Information System (INIS)

    In many dynamic gas-phase reaction processes, there is great interest to measure the distribution of minor constituents, i.e. −3 by volume (1000 ppm). One such case is the after-treatment of automotive gasoline engine exhaust by catalytic conversion, where a characteristic challenge is to image the distribution of 10 ppm (average) of carbon monoxide (CO) at 1000 frames per second across a 50 mm diameter exhaust pipe; this particular problem has been pursued as a case study. In this paper, we present a novel electronic scheme that achieves the required measurement of around 10−3 absorption with 10−4 precision at kHz bandwidth. This was not previously achievable with any known technology. We call the new scheme Auto-Digital Gain Balancing. It is amenable to replication for many simultaneous measurement channels, and it permits simultaneous measurement of multiple species, in some circumstances. Experimental demonstrations are presented in the near-infrared. In single scans of a tunable diode laser, measurements of both CO and CO2 have been made with 20 dB signal-to-noise ratio at peak absorption. This work paves the way for chemical species tomography of minor constituents in many dynamic gas-phase systems

  14. Balanced Scorecard

    OpenAIRE

    Ahonen, Tiina

    2015-01-01

    Tasapainotetun tuloskortin eli Balanced Scorecardin avulla organisaatiolla on mahdollisuus saada toiminnasta perinteisiä taloudellisia raportteja parempi kuva. Balanced Scorecard huomioi taloudellisten tunnuslukujen lisäksi myös asiakkaiden, sisäisten prosessien sekä oppimisen ja kasvun näkökulman. Tämän opinnäytetyön tavoitteena oli suunnitella suoritusmittaristo pk-yritykselle. Tutkimuksella haettiin Balance Scorecardin kautta vahvistusta ja tukea kohdeyrityksen sisäiseen laskentaan ja ...

  15. Applying a Self-Made Automobile Heterodyne Interferometer to Measure the Parameters of Twisted Nematic Liquid Crystal

    Directory of Open Access Journals (Sweden)

    Shinn-Fwu Wang

    2012-01-01

    Full Text Available A self-made automobile heterodyne interferometer with a closed control loop is presented. In addition, we will apply the self-made automobile heterodyne interferometer to measure the parameters of optically compensated twisted nematic liquid crystal (TN LC. It is worthy to be mentioned that the self-made automobile heterodyne interferometer has a compact size because all the optical components are installed in the mechanism of the system. Besides, the self-made automobile heterodyne interferometer has some much more merits, for example, automobile control, a simple setup, in real-time test, reliability, and so forth. Besides, it is very stable because of its common optical path insensitive to environmental disturbances. And its feasibility is demonstrated.

  16. Phase measurement of various commercial heterodyne He–Ne-laser interferometers with stability in the picometer regime

    International Nuclear Information System (INIS)

    In order to be able to resolve displacements of a picometer with widely used commercially available heterodyne interferometers, an advanced phase meter was developed at PTB. Key to this level of accuracy is the use of a state-of-the-art analogue-to-digital converter (ADC) board enabling the implementation of a phase-evaluation method by using embedded field programmable gate arrays. Experimental results obtained with commercially available heterodyne laser interferometer components prove that the proposed phase-evaluation procedure is capable of interpolating an optical fringe down into the picometer regime. The phase evaluation was moreover extended to track simultaneously two heterodyne beat frequencies with only two photodetectors and ADCs. Potential limitations of the long-term stability of heterodyne interferometers are discussed. The phase meter was tested, has been readily applied, can be easily adapted and is therefore to be used in a wide field of applications. (paper)

  17. Simple digital phase-measuring algorithm for low-noise heterodyne interferometry

    CERN Document Server

    Kokuyama, Wataru; Ohta, Akihiro; Hattori, Koichiro

    2016-01-01

    We present a digital algorithm for measuring the phase difference between two sinusoidal signals that combines the modified fringe-counting method with two-sample zero crossing to enable sequential signal processing. This technique can be applied to a phase meter for measuring dynamic phase differences with high resolution, particularly for heterodyne interferometry. The floor noise obtained from a demonstration with an electrical apparatus is $5\\times10^{-8} \\mathrm{rad/\\sqrt{Hz}}$ at frequencies above approximately 0.1 Hz. In addition, by applying this method to a commercial heterodyne interferometer, the floor-noise level is confirmed to be $7\\times10^{-14} \\mathrm{m/\\sqrt{Hz}}$ from 4 kHz to 1 MHz. We also confirm the validity of the algorithm by comparing its results with those from a standard homodyne interferometer for measuring shock-motion peak acceleration greater than 5000 m/s^2 and a 10 mm stroke.

  18. Improved optical pulse heterodyne demodulation scheme for fiber-optic interferometric sensors

    Science.gov (United States)

    Lai, Haiqiang; Wang, Jianfei; Tu, Xiaobo; Meng, Zhou

    2015-10-01

    An improved optical pulse heterodyne demodulation scheme for fiber-optic interferometric sensors is demonstrated. This scheme uses two series-connected Acoustic-optic modulators (AOMs) as intensity modulator and frequency shifter respectively. Compared to the traditional optical heterodyne demodulation structure, this scheme eliminates the polarization-induced signal fading and the noise floor is lowered for using the Michelson-configuration delay structure and Faraday rotation mirrors (FRMs) in the optic architecture of system. At the same time, the architecture of this scheme is not complicated and can be used to complex a large sensor array. Experimental results show that the phase noise floor of this demodulation scheme is flat and reaches -99dB/sqrt(Hz) at frequencies above 300 Hz.

  19. Full-field refractive index distribution measurement of a gradient-index lens with heterodyne interferometry

    International Nuclear Information System (INIS)

    A light beam coming from a circular heterodyne light source with an electro-optic modulator is incident on a gradient-index lens obliquely. The reflected light passes through an analyzer and an imaging lens, and is recorded by a fast CMOS camera. A group of periodic sinusoidal segments recorded by each pixel is modified, and its associated phase is derived with a unique technique. The processes are applied to other pixels; the two-dimensional phase distribution can be obtained similarly. The estimated data are substituted into the special equations derived from Fresnel's equations, and the full-field refractive index distribution of the gradient-index lens can be obtained. This method has the merits of both common-path interferometry and heterodyne interferometry

  20. Terahertz quantum cascade laser as local oscillator in a heterodyne receiver

    OpenAIRE

    Hübers, H. -W.; Pavlov, S.G.; Semenov, A. D.; Köhler, R.; Mahler, I; Tredicucci, A.; Beere, H.E.; Ritchie, D. A.; Linfield, E.H.

    2005-01-01

    Terahertz quantum cascade lasers have been investigated with respect to their performance as a local oscillator in a heterodyne receiver. The beam profile has been measured and transformed in to a close to Gaussian profile resulting in a good matching between the field patterns of the quantum cascade laser and the antenna of a superconducting hot electron bolometric mixer. Noise temperature measurements with the hot electron bolometer and a 2.5 THz quantum cascade laser yielded the same resul...

  1. Absolute intensity calibration of the 32-channel heterodyne radiometer on experimental advanced superconducting tokamak.

    Science.gov (United States)

    Liu, X; Zhao, H L; Liu, Y; Li, E Z; Han, X; Domier, C W; Luhmann, N C; Ti, A; Hu, L Q; Zhang, X D

    2014-09-01

    This paper presents the results of the in situ absolute intensity calibration for the 32-channel heterodyne radiometer on the experimental advanced superconducting tokamak. The hot/cold load method is adopted, and the coherent averaging technique is employed to improve the signal to noise ratio. Measured spectra and electron temperature profiles are compared with those from an independent calibrated Michelson interferometer, and there is a relatively good agreement between the results from the two different systems. PMID:25273727

  2. Synthetic-aperture experiment in the visible with on-axis digital heterodyne holography

    CERN Document Server

    Clerc, Frédérique Le; Collot, Laurent

    2011-01-01

    We have developed a new on-axis digital holographic technique, heterodyne holography. The resolution of this technique is limited mainly by the amount of data recorded on two-dimensional photodetectors, i.e., the number of pixels and their size. We demonstrate that it is possible to increase the resolution linearly with the amount of recorded data by aperture synthesis as done in the radar technique but with an optical holographic field.

  3. Super-heterodyne light scattering on interacting colloidal suspensions: theory and experiment

    OpenAIRE

    Palberg, Thomas; Reiber, Holger; Köller, Tetyana; Medebach, Martin; Nägele, Gerhard

    2008-01-01

    In soft matter structure couples to flow and vice versa. Complementary to structural investigations, we here are interested in the determination of particle velocities of charged colloidal suspensions of different structure under flow. In a combined effort of theory and experiment we determine the Fourier transform of the super-heterodyne field auto-correlation function (power spectrum) which in frequency space is found to be well separated from homodyne contributions and low frequency noise....

  4. Absolute intensity calibration of the 32-channel heterodyne radiometer on experimental advanced superconducting tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Liu, X.; Zhao, H. L.; Liu, Y., E-mail: liuyong@ipp.ac.cn; Li, E. Z.; Han, X.; Ti, A.; Hu, L. Q.; Zhang, X. D. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Domier, C. W.; Luhmann, N. C. [Department of Electrical and Computer Engineering, University of California at Davis, Davis, California 95616 (United States)

    2014-09-15

    This paper presents the results of the in situ absolute intensity calibration for the 32-channel heterodyne radiometer on the experimental advanced superconducting tokamak. The hot/cold load method is adopted, and the coherent averaging technique is employed to improve the signal to noise ratio. Measured spectra and electron temperature profiles are compared with those from an independent calibrated Michelson interferometer, and there is a relatively good agreement between the results from the two different systems.

  5. Communication: Atomic force detection of single-molecule nonlinear optical vibrational spectroscopy

    International Nuclear Information System (INIS)

    Atomic Force Microscopy (AFM) allows for a highly sensitive detection of spectroscopic signals. This has been first demonstrated for NMR of a single molecule and recently extended to stimulated Raman in the optical regime. We theoretically investigate the use of optical forces to detect time and frequency domain nonlinear optical signals. We show that, with proper phase matching, the AFM-detected signals closely resemble coherent heterodyne-detected signals. Applications are made to AFM-detected and heterodyne-detected vibrational resonances in Coherent Anti-Stokes Raman Spectroscopy (χ(3)) and sum or difference frequency generation (χ(2))

  6. Lock-in camera based heterodyne holography for ultrasound-modulated optical tomography inside dynamic scattering media

    Science.gov (United States)

    Liu, Yan; Shen, Yuecheng; Ma, Cheng; Shi, Junhui; Wang, Lihong V.

    2016-06-01

    Ultrasound-modulated optical tomography (UOT) images optical contrast deep inside scattering media. Heterodyne holography based UOT is a promising technique that uses a camera for parallel speckle detection. In previous works, the speed of data acquisition was limited by the low frame rates of conventional cameras. In addition, when the signal-to-background ratio was low, these cameras wasted most of their bits representing an informationless background, resulting in extremely low efficiencies in the use of bits. Here, using a lock-in camera, we increase the bit efficiency and reduce the data transfer load by digitizing only the signal after rejecting the background. Moreover, compared with the conventional four-frame based amplitude measurement method, our single-frame method is more immune to speckle decorrelation. Using lock-in camera based UOT with an integration time of 286 μs, we imaged an absorptive object buried inside a dynamic scattering medium exhibiting a speckle correlation time ( τc ) as short as 26 μs. Since our method can tolerate speckle decorrelation faster than that found in living biological tissue ( τc ˜ 100-1000 μs), it is promising for in vivo deep tissue non-invasive imaging.

  7. Balance System

    Science.gov (United States)

    1988-01-01

    TherEx Inc.'s AT-1 Computerized Ataxiameter precisely evaluates posture and balance disturbances that commonly accompany neurological and musculoskeletal disorders. Complete system includes two-strain gauged footplates, signal conditioning circuitry, a computer monitor, printer and a stand-alone tiltable balance platform. AT-1 serves as assessment tool, treatment monitor, and rehabilitation training device. It allows clinician to document quantitatively the outcome of treatment and analyze data over time to develop outcome standards for several classifications of patients. It can evaluate specifically the effects of surgery, drug treatment, physical therapy or prosthetic devices.

  8. Balance (or Vestibular) Rehabilitation

    Science.gov (United States)

    ... for the Public / Hearing and Balance Balance (or Vestibular) Rehabilitation Audiologic (hearing), balance, and medical diagnostic tests help indicate whether you are a candidate for vestibular (balance) rehabilitation. Vestibular rehabilitation is an individualized balance ...

  9. First results from ground-based CO2 remote sounding using high-resolution thermal IR laser heterodyne radiometry

    Science.gov (United States)

    Hoffmann, Alex; Huebner, Marko; Macleod, Neil; Weidmann, Damien

    2016-04-01

    Over the course of the last decade, the Laser Spectroscopy Group at RAL Space has considerably furthered the passive remote sensing technique of thermal IR Laser Heterodyne Radiometry (LHR), and applied it successfully to the ground-based sounding of atmospheric profiles of a variety of trace gases, including methane. LHR is underpinned by coherent detection technology and ideally shot noise-limited, which can significantly enhance the signal-to-noise ratio of acquired atmospheric spectra over conventional direct detection spectrometers when high spectral (>500,000 resolving power) and high spatial resolutions are needed. These benefits allow probing optimized narrow spectral windows (1 cm-1) with full absorption lineshape information, useful for trace gas vertical profiling. Furthermore, LHR has a high potential for miniaturization into a rugged, unprecedentedly compact package, through hollow waveguide optical integration, facilitating its deployment in ground-based observation networks, as well as on a variety of airborne and spaceborne platforms, whilst retaining its high specifications. This makes LHR well-suited to the remote sounding of key greenhouse gases, in particular carbon dioxide, as observations with high precision and accuracy are crucial to discriminate trends and small variations over a substantial background concentration, and in order to contribute to flux estimations in top-down carbon cycle inversion approaches and anthropogenic emission monitoring. Here, we present a new optical bench-based LHR prototype that has been specifically built to demonstrate CO2 sounding in the thermal IR. The instrument has been coupled to a new permanently installed solar tracker to take a long-term measurement series in solar occultation mode, and to assess the performance of the instrument. We discuss its theoretical performance modelled using an Observation System Simulator, and showcase first results from a 6 months' archive, with observations undergoing

  10. IR heterodyne spectrometer MILAHI for continuous monitoring observatory of Martian and Venusian atmospheres at Mt. Haleakalā, Hawaii

    Science.gov (United States)

    Nakagawa, Hiromu; Aoki, Shohei; Sagawa, Hideo; Kasaba, Yasumasa; Murata, Isao; Sonnabend, Guido; Sornig, Manuela; Okano, Shoichi; Kuhn, Jeffrey R.; Ritter, Joseph M.; Kagitani, Masato; Sakanoi, Takeshi; Taguchi, Makoto; Takami, Kosuke

    2016-07-01

    A new Mid-Infrared Laser Heterodyne Instrument (MILAHI) with >106 resolving power at 7-12 μm was developed for continuous monitoring of planetary atmospheres by using dedicated ground-based telescopes for planetary science at Mt. Haleakalā, Hawaii. Room-temperature-type quantum cascade lasers (QCLs) that cover wavelength ranges of 7.69-7.73, 9.54-9.59, and 10.28-10.33 μm have been newly installed as local oscillators to allow observation of CO2, CH4, H2O2, H2O, and HDO. Modeling and predictions by radiative transfer code gave the following scientific capabilities and measurement sensitivities of the MILAHI. (1) Temperature profiles are achieved at altitudes of 65-90 km on Venus, and the ground surface to 30 km on Mars. (2) New wind profiles are provided at altitudes of 75-90 km on Venus, and 5-25 km on Mars. (3) Direct measurements of the mesospheric wind and temperature are obtained from the Doppler-shifted emission line at altitudes of 110 km on Venus and 75 km on Mars. (4) Detections of trace gases and isotopic ratios are performed without any ambiguity of the reproducing the terrestrial atmospheric absorptions in the observed wavelength range. A HDO measurement of twice the Vienna Standard Mean Ocean Water (VSMOW) can be obtained by 15-min integration, while H2O of 75 ppm is provided by 3.62-h integration. The detectability of the 100 ppb-CH4 on Mars corresponds to an integration time of 32 h.

  11. Ground Based Observation of Isotopic Oxygen in the Martian Atmosphere Using Infrared Heterodyne Spectroscopy

    Science.gov (United States)

    Smith, R. L.; Kostiuk, T.; Livengood, T. A.; Fast, K. E.; Hewagama, T.; Delgado, J. D.; Sonnabend, G.

    2010-01-01

    Infrared heterodyne spectra of isotopic CO2 in the Martian atmosphere were obtained using the Goddard Heterodyne Instrument for Planetary Wind and Composition, HIPWAC, which was interfaced with the 3-meter telescope at the NASA Infrared Telescope Facility- Spectra were colle cted at a resolution of lambda/delta lambda=10(exp 7). Absorption fea tures of the CO2 isotopologues have been identified from which isotop ic ratios of oxygen have been determined. The isotopic ratios O-17/O -16 and O-18/O-16 in the Martian atmosphere can be related to Martian atmospheric evolution and can be compared to isotopic ratios of oxyg en in the Earth's atmosphere. Isotopic carbon and oxygen are importa nt constraints on any theory for the erosion of the Martian primordia l atmosphere and the interaction between the atmosphere and surface o r subsurface chemical reservoirs. This investigation explored the pr esent abundance of the stable isotopes of oxygen in Mars' atmospheric carbon dioxide by measuring rovibrational line absorption in isotop ic species of CO2 using groundbased infrared heterodyne spectroscopy in the vicinity of the 9.6 micron and 10.6 micron CO2 lasing bands. T he target transitions during this observation were O-18 C-12 O-16 as well as O-178 C-12 O-16 and O-16 C-113 O-16 at higher resolving power of lambda/delta lambda=10(exp 7) and with high signal-to-noise ratio (longer integration time) in order to fully characterize the absorpt ion line profiles. The fully-resolved lineshape of both the strong n ormal-isotope and the weak isotopic CO2 lines were measured simultane ously in a single spectrum.

  12. AMiBA: Broadband Heterodyne Cosmic Microwave Background Interferometry

    Science.gov (United States)

    Chen, Ming-Tang; Li, Chao-Te; Hwang, Yuh-Jing; Jiang, Homin; Altamirano, Pablo; Chang, Chia-Hao; Chang, Shu-Hao; Chang, Su-Wei; Chiueh, Tzi-Dar; Chu, Tah-Hsiung; Han, Chih-Chiang; Huang, Yau-De; Kesteven, Michael; Kubo, Derek; Martin-Cocher, Pierre; Oshiro, Peter; Raffin, Philippe; Wei, Tashun; Wang, Huei; Wilson, Warwick; Ho, Paul T. P.; Huang, Chih-Wei; Koch, Patrick; Liao, Yu-Wei; Lin, Kai-Yang; Liu, Guo-Chin; Molnar, Sandor M.; Nishioka, Hiroaki; Umetsu, Keiichi; Wang, Fu-Cheng; Wu, Jiun-Huei Proty

    2009-04-01

    The Y. T. Lee Array for Microwave Background (AMiBA) has reported the first results on the detection of galaxy clusters via the Sunyaev-Zel'dovich effect. The objectives required small reflectors in order to sample large-scale structures (20'), while interferometry provided modest resolutions (2'). With these constraints, we designed for the best sensitivity by utilizing the maximum possible continuum bandwidth matched to the atmospheric window at 86-102 GHz, with dual polarizations. A novel wide-band analog correlator was designed that is easily expandable for more interferometer elements. Monolithic millimeter-wave integrated circuit technology was used throughout as much as possible in order to miniaturize the components and to enhance mass production. These designs will find application in other upcoming astronomy projects. AMiBA is now in operation since 2006, and we are in the process to expand the array from seven to 13 elements.

  13. Wide measurement range scanning heterodyne interferometer utilizing astigmatic position sensing scheme

    Science.gov (United States)

    Park, Youngkyu; Kim, Kyoung-Eop; Kim, Seong-Jin; Park, June-Gyu; Joo, Young-Hun; Shin, Bu Hyun; Lee, Seung-Yop; Cho, Kyuman

    2011-08-01

    A scanning heterodyne I/Q-interferometer scheme is proposed to overcome phase ambiguity caused by the periodic nature of its phase-dependent signal. A position sensing scheme using an astigmatic method in the confocal arrangement has been interfaced to the interferometer to retrieve the real phase value during a scanning process. The experimental results show that the vertical measurement range can be expanded up to 16μm. The potential of this interferometer on the scanning microscopy of a rough surface is discussed.

  14. Electronic frequency modulation for the increase of maximum measurable velocity in a heterodyne laser interferometer

    International Nuclear Information System (INIS)

    A Zeeman-type He-Ne laser is frequently used as a heterodyne laser due to the simple construction and the small loss of a light. However, the low beat frequency of the Zeeman-type laser limits the maximum measurable velocity. In this article, an electronic frequency modulation algorithm is proposed to overcome the drawback of the low velocity measurement capability by increasing the beat frequency electronically. The brief analysis, the measurement scheme of the proposed algorithm, and the experimental results are presented. It is demonstrated that the proposed algorithm is proven to enhance the maximum measurable velocity

  15. Simple method for reducing the first-order optical nonlinearity in a heterodyne laser interferometer.

    Science.gov (United States)

    Fu, Haijin; Hu, Pengcheng; Tan, Jiubin; Fan, Zhigang

    2015-07-10

    A simple method was proposed by using a tunable attenuator fitted in the reference or measurement arm of a heterodyne laser interferometer to adjust the values of mixing laser beams while the spectrum of the measurement signal is monitored using a signal analyzer. The effectiveness of the proposed method in reducing the first-order optical nonlinearity was verified through experiments. Results indicated that the peak value of the first-order optical nonlinearity could be reduced from 5.15 to 0.24 nm. It was therefore concluded that the proposed method was applicable to ultraprecision laser interferometry. PMID:26193410

  16. A new method for measuring phase shift in heterodyne interferometric measurement

    International Nuclear Information System (INIS)

    A new method for analysing the phase shift of heterodyne interferometric beat is developed. The phase shift is obtained directly from the change in the probe beat period without comparing with reference beat. According to this method an electric circuit system has been designed, combined with an HCN laser or microwave interferometer for the measurement of line-integrated electron density of plasma in Compact Helical System (CHS). The experimental results show that this method is effective. The minimum measurable phase shift is determined by the ratio of beat frequency to the counting clock frequency, and the maximum measurable phase shift is infinite in principle. (author)

  17. Self-heterodyne detection of the {\\it in-situ} phase of an atomic-SQUID

    CERN Document Server

    Mathew, Ranchu; Eckel, Stephen; Jendrzejewski, Fred; Campbell, Gretchen K; Edwards, Mark; Tiesinga, Eite

    2015-01-01

    We present theoretical and experimental analysis of an interferometric measurement of the {\\it in-situ} phase drop across and current flow through a rotating barrier in a toroidal Bose-Einstein condensate (BEC). This experiment is the atomic analog of the rf-superconducting quantum interference device (SQUID). The phase drop is extracted from a spiral-shaped density profile created by the spatial interference of the expanding toroidal BEC and a reference BEC after release from all trapping potentials. We characterize the interferometer when it contains a single particle, which is initially in a coherent superposition of a torus and reference state, as well as when it contains a many-body state in the mean-field approximation. The single-particle picture is sufficient to explain the origin of the spirals, to relate the phase-drop across the barrier to the geometry of a spiral, and to bound the expansion times for which the {\\it in-situ} phase can be accurately determined. Mean-field estimates and numerical sim...

  18. Derivation of a Monte Carlo method for modeling heterodyne detection in optical coherence tomography systems

    DEFF Research Database (Denmark)

    Tycho, Andreas; Jørgensen, Thomas Martini; Andersen, Peter E.

    2002-01-01

    A Monte Carlo (MC) method for modeling optical coherence tomography (OCT) measurements of a diffusely reflecting discontinuity emb edded in a scattering medium is presented. For the first time to the authors' knowledge it is shown analytically that the applicability of an MC approach to this...... from the sample will have a finite spatial coherence that cannot be accounted for by MC simulation. To estimate this intensity distribution adequately we have developed a novel method for modeling a focused Gaussian beam in MC simulation. This approach is valid for a softly as well as for a strongly...... focused beam, and it is shown that in free space the full three-dimensional intensity distribution of a Gaussian beam is obtained. The OCT signal and the intensity distribution in a scattering medium have been obtained for several geometries with the suggested MC method; when this model and a recently...

  19. FPGA-Based Networked Phasemeter for a Heterodyne Interferometer

    Science.gov (United States)

    Rao, Shanti

    2009-01-01

    A document discusses a component of a laser metrology system designed to measure displacements along the line of sight with precision on the order of a tenth the diameter of an atom. This component, the phasemeter, measures the relative phase of two electrical signals and transfers that information to a computer. Because the metrology system measures the differences between two optical paths, the phasemeter has two inputs, called measure and reference. The reference signal is nominally a perfect square wave with a 50- percent duty cycle (though only rising edges are used). As the metrology system detects motion, the difference between the reference and measure signal phases is proportional to the displacement of the motion. The phasemeter, therefore, counts the elapsed time between rising edges in the two signals, and converts the time into an estimate of phase delay. The hardware consists of a circuit board that plugs into a COTS (commercial, off-the- shelf) Spartan-III FPGA (field-programmable gate array) evaluation board. It has two BNC inputs, (reference and measure), a CMOS logic chip to buffer the inputs, and an Ethernet jack for transmitting reduced-data to a PC. Two extra BNC connectors can be attached for future expandability, such as external synchronization. Each phasemeter handles one metrology channel. A bank of six phasemeters (and two zero-crossing detector cards) with an Ethernet switch can monitor the rigid body motion of an object. This device is smaller and cheaper than existing zero-crossing phasemeters. Also, because it uses Ethernet for communication with a computer, instead of a VME bridge, it is much easier to use. The phasemeter is a key part of the Precision Deployable Apertures and Structures strategic R&D effort to design large, deployable, segmented space telescopes.

  20. Balancing Risk

    DEFF Research Database (Denmark)

    Nygaard, Lene; Rossen, Camilla Blach; Buus, Niels

    2015-01-01

    This study explored how eight pregnant women diagnosed with depression managed the decision whether or not to take antidepressants during pregnancy. In total, 11 interviews were conducted and analysed by means of constructivist grounded theory. The major category constructed was Balancing risk......, with two minor categories: Assessing depression and antidepressants and Evaluating the impact of significant others. The participants tried to make the safest decision, taking all aspects of their life into consideration. They described successful decision-making in the context of managing social norms...

  1. Social Balance Theory

    OpenAIRE

    Hokky Situngkir; Deni Khanafiah

    2004-01-01

    We construct a model based on social balance theory proposed by Fritz Heider to analyze the interpersonal network among social agents. The model of social balance theory provides us an interesting tool to see how a social group evolves to the possible balance state. We introduce the balance index that can be used to measure social balance in macro structure level (global balance index) or in micro structure (local balance index) to see how the local balance index influences the global balance...

  2. Simple digital phase-measuring algorithm for low-noise heterodyne interferometry

    Science.gov (United States)

    Kokuyama, Wataru; Nozato, Hideaki; Ohta, Akihiro; Hattori, Koichiro

    2016-08-01

    We present a digital algorithm for measuring the phase of a sinusoidal signal that combines the modified digital fringe-counting method with two-sample zero crossing to enable sequential signal processing. This technique can be applied to a phase meter for measuring dynamic phase differences between two sinusoidal signals with high resolution, particularly for heterodyne interferometry. The floor noise obtained from a demonstration with an electrical apparatus is 5× {{10}-8} \\text{rad}\\text{/}{{\\sqrt{\\text{Hz}}}{}} at frequencies above approximately 0.1 Hz for 80 kHz signal frequency. In addition, by applying this method to a commercial heterodyne interferometer with a modulation frequency of 80 MHz, the floor-noise level is confirmed to be 7× {{10}-14}\\text{m}\\text{/}{{\\sqrt{\\text{Hz}}}{}} from 4 kHz to 1 MHz. We also confirm the validity of the algorithm by comparing its results with those from a standard homodyne interferometer for measuring shock-motion peak acceleration greater than 5000 \\text{m} {{\\text{s}}-2} and a 10 mm stroke.

  3. Femtosecond Heterodyne Transient Grating Spectroscopic Studies of Intramolecular Charge Transfer Character of Peridinin and Peridinin Analogs

    Science.gov (United States)

    Bishop, Michael; Khosravi, Soroush; Obaid, Razib; Whitelock, Hope; Carroll, Ann Marie; Lafountain, Amy; Frank, Harry; Beck, Warren; Gibson, George; Berrah, Nora

    2016-05-01

    The peridinin chlorophyll-a protein is a light harvesting complex found in several species of dinoflagellates. Peridinin absorbs strongly in the mid-visible spectral region and, despite the lack of a strong permanent dipole moment in its lowest energy excited state, is able to transfer excitation energy quickly and efficiently to chlorophyll-a. It is believed that the high efficiency arises from the development of intramolecular charge-transfer (ICT) character upon photoexcitation. Recently, heterodyne transient grating spectroscopy has been used to study the ultrafast (ICT character in the case of peridinin, but up to now the work has not provided appropriate control experiments. The present experiments examine peridinin and two peridinin analogs, S1-peridinin and S2-peridinin. S1-peridinin is reported to have greatly diminished ICT character, and S2-peridinin is reported to have little-or-no ICT character. Heterodyne transient grating data will be presented and provide a more unambiguous characterization spectral and kinetic properties associated with the peridinin ICT state. Funded by the DoE-BES, Grant No. DE-SC0012376.

  4. Using the Heterodyne Method to Measure Velocities on Shock Physics Experiments

    Science.gov (United States)

    Strand, Oliver

    2007-06-01

    Velocimetry is an important diagnostic for shock physics experiments. Velocities for these types of experiments can be in the kilometer-per-second range. We have developed a new velocimetry diagnostic for use on shock physics experiments that is based upon the heterodyne method. This diagnostic is easily assembled from commercially available parts developed for the telecommunication industry. The entire system uses single mode fibers to transport the signals from the laser to the probes and back to the detectors. We mix the Doppler-shifted light from the moving surface with non-shifted light from the laser itself to generate a beat signal at the detector. For this system using 1550 nm lasers, a velocity of 1 km/s generates a beat signal of 1.29 GHz. The detectors and the digitizers must have high-bandwidth capabilities to faithfully follow the beat waveform to allow a determination of the frequency as a function of time. Our current system has a maximum velocity capability of over 5 km/s. This paper will describe the heterodyne velocimeter and will present some of the data that has been taken with it. This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory, under contract No. W-7405-Eng-48.

  5. A heterodyne interferometer with periodic nonlinearities smaller than ±10 pm

    International Nuclear Information System (INIS)

    The PTB developed a new optical heterodyne interferometer in the context of the European joint research project ‘Nanotrace’. A new optical concept using plane-parallel plates and spatially separated input beams to minimize the periodic nonlinearities was realized. Furthermore, the interferometer has the resolution of a double-path interferometer, compensates for possible angle variations between the mirrors and the interferometer optics and offers a minimal path difference between the reference and the measurement arm. Additionally, a new heterodyne phase evaluation based on an analogue to digital converter board with embedded field programmable gate arrays was developed, providing a high-resolving capability in the single-digit picometre range. The nonlinearities were characterized by a comparison with an x-ray interferometer, over a measurement range of 2.2 periods of the optical interferometer. Assuming an error-free x-ray interferometer, the nonlinearities are considered to be the deviation of the measured displacement from a best-fit line. For the proposed interferometer, nonlinearities smaller than ±10 pm were observed without any quadrature fringe correction. (paper)

  6. First supra-THz Heterodyne Array Receivers for Astronomy with the SOFIA Observatory

    CERN Document Server

    Risacher, Christophe; Stutzki, Juergen; Huebers, Heinz-Wilhelm; Buechel, Denis; Graf, Urs U; Heyminck, Stefan; Honingh, Cornelia E; Jacobs, Karl; Klein, Bernd; Klein, Thomas; Leinz, Christian; Puetz, Patrick; Reyes, Nicolas; Ricken, Oliver; Wunsch, Hans-Joachim; Fusco, Paul; Rosner, Stefan

    2015-01-01

    We present the upGREAT THz heterodyne arrays for far-infrared astronomy. The Low Frequency Array (LFA) is designed to cover the 1.9-2.5 THz range using 2x7-pixel waveguide-based HEB mixer arrays in a dual polarization configuration. The High Frequency Array (HFA) will perform observations of the [OI] line at ~4.745 THz using a 7-pixel waveguide-based HEB mixer array. This paper describes the common design for both arrays, cooled to 4.5 K using closed- cycle pulse tube technology. We then show the laboratory and telescope characterization of the first array with its 14 pixels (LFA), which culminated in the successful commissioning in May 2015 aboard the SOFIA airborne observatory observing the [CII] fine structure transition at 1.905 THz. This is the first successful demonstration of astronomical observations with a heterodyne focal plane array above 1 THz and is also the first time high- power closed-cycle coolers for temperatures below 4.5 K are operated on an airborne platform.

  7. Wide-field heterodyne interferometric vibrometry for two-dimensional surface vibration measurement

    Science.gov (United States)

    Choi, Samuel; Maruyama, Yuta; Suzuki, Takamasa; Nin, Fumiaki; Hibino, Hiroshi; Sasaki, Osami

    2015-12-01

    Conventional laser Doppler vibrometry and heterodyne interferometry suffer during the simultaneous measurement of the spatial distribution of vibration parameters such as the amplitude, frequency and phase in a wide field of view. Although demand is increasing for methods that can measure vibrations over a wide field of view for a wide range of applications from industrial product inspections to biological measurements, full-field (FF) techniques for high-speed vibration measurements without a spatial scan are untapped. We propose a new method for high-speed FF vibration measurement that can easily be combined with profilometry and tomographic interferometry using a conventional CCD or CMOS camera. In principle, the measurable vibration frequency is unrestricted because the heterodyne signal produced by the modulated interferogram can be controlled to accommodate the CCD frame rate. The validity of the proposed method and the measurement accuracy of the spatial vibration amplitude were evaluated through simulations and experiments. In experiments, the spatial vibration parameters of a mirror vibrated at a frequency of 1 kHz and amplitude of approximately 5-65 nm were successfully measured with a spatial fluctuation of 3%-6.5%.

  8. Fast-scanning heterodyne receiver for measurement of the electron cyclotron emission from high-temperature plasmas

    International Nuclear Information System (INIS)

    A fast-scanning heterodyne receiver was developed that measures the fundamental cyclotron emission from the PLT plasma and thus ascertains the time evolution of the electron temperature profile. The receiver scans 60 to 90 GHz every 10 milliseconds and is interfaced to a computer for completely automated calibrated temperature measurements

  9. Transient and time-resolved four-wave mixing with collinear pump and probe pulses using the heterodyne technique

    DEFF Research Database (Denmark)

    Mecozzi, A.; Mørk, Jesper

    1998-01-01

    We review the recently proposed heterodyne technique for four-wave mixing experiments with collinear and co-polarized pulses. We discuss issues related to the parameters of the nonlinear dynamics of the sample that can be extracted by this technique....

  10. A method of measuring micro-impulse with torsion pendulum based on multi-beam laser heterodyne

    Institute of Scientific and Technical Information of China (English)

    Li Yan-Chao; Wang Chun-Hui

    2012-01-01

    In this paper,we propose a novel method of multi-beam laser heterodyne measurement for micro-impulse.The measurement of the micro-impulse,which is converted into the measurement of the small tuning angle of the torsion pendulum,is realized by considering the interaction between pulse laser and working medium.Based on Doppler effect and heterodyne technology,the information regarding the small tuning angle is loaded to the frequency difference of the multi-beam laser heterodyne signal by the frequency modulation of the oscillating mirror,thereby obtaining many values of the small tuning angle after the multi-beam laser heterodyne signal demodulation simultaneously.Processing these values by weighted-average,the small tuning angle can be obtained accurately and the value of the micro-impulse can eventually be calculated.Using Polyvinylchlorid+2%C as a working medium,this novel method is used to simulate the value of the micro-impulse by MATLAB which is generated by considering the interaction between the pulse laser and the working medium,the obtained result shows that the relative error of this method is just 0.5%.

  11. A 490 GHz planar circuit balanced Nb-Al$_\\mathbf{2}$O$_{\\mathbf{3}}$-Nb quasiparticle mixer for radio astronomy: Application to quantitative local oscillator noise determination

    CERN Document Server

    Westig, M P; Jacobs, K; Stutzki, J; Schultz, M; Schomacker, F; Honingh, C E

    2012-01-01

    This article presents a heterodyne experiment which uses a 380-520 GHz planar circuit balanced Nb-$\\mathrm{Al_2O_3}$-Nb superconductor-insulator-superconductor (SIS) quasiparticle mixer with 4-8 GHz instantaneous intermediate frequency (IF) bandwidth to quantitatively determine local oscillator (LO) noise. A balanced mixer is a unique tool to separate noise at the mixer's LO port from other noise sources. This is not possible in single-ended mixers. The antisymmetric IV characteristic of a SIS mixer further helps to simplify the measurements. The double-sideband receiver sensitivity of the balanced mixer is 2-4 times the quantum noise limit $h\

  12. Detection of the water reservoir in a forming planetary system

    NARCIS (Netherlands)

    M.R. Hogerheijde; E.A. Bergin; C. Brinch; L.I. Cleeves; J. K.J. Fogel; G.A. Blake; C. Dominik; D.C. Lis; G. Melnick; D. Neufeld; O. Panić; J.C. Pearson; L. Kristensen; U.A. Yıldız; E.F. van Dishoeck

    2011-01-01

    Icy bodies may have delivered the oceans to the early Earth, yet little is known about water in the ice-dominated regions of extrasolar planet-forming disks. The Heterodyne Instrument for the Far-Infrared on board the Herschel Space Observatory has detected emission lines from both spin isomers of c

  13. Balanced Scorecard

    OpenAIRE

    Kytka, Roman

    2008-01-01

    V současnosti se podniky setkávají s řadou přístupů k řízení společností a velmi častými pojícími prvky bývají zejména náklady, efektivita a výkonnost. Z nepřeberné řady nástrojů k řízení společností určených tato práce blíže seznamuje s metodikou Balanced Scorecard (BSC), koncepčním rámcem ITIL a metodikou Cobit. Jednotlivě zde jsou představeny dílčí metodiky a rámce. Míra tohoto seznámení je úměrná potřebám práce, tzn. není cílem představit ITIL či Cobit úplně detailně. Naopak zde jsou podc...

  14. Terahertz Radiation Heterodyne Detector Using Two-Dimensional Electron Gas in a GaN Heterostructure

    Science.gov (United States)

    Karasik, Boris S.; Gill, John J.; Mehdi, Imran; Crawford, Timothy J.; Sergeev, Andrei V.; Mitin, Vladimir V.

    2012-01-01

    High-resolution submillimeter/terahertz spectroscopy is important for studying atmospheric and interstellar molecular gaseous species. It typically uses heterodyne receivers where an unknown (weak) signal is mixed with a strong signal from the local oscillator (LO) operating at a slightly different frequency. The non-linear mixer devices for this frequency range are unique and are not off-the-shelf commercial products. Three types of THz mixers are commonly used: Schottky diode, superconducting hot-electron bolometer (HEB), and superconductor-insulation-superconductor (SIS) junction. A HEB mixer based on the two-dimensional electron gas (2DEG) formed at the interface of two slightly dissimilar semiconductors was developed. This mixer can operate at temperatures between 100 and 300 K, and thus can be used with just passive radiative cooling available even on small spacecraft.

  15. Heterodyne mixing of millimetre electromagnetic waves and sub-THz sound in a semiconductor device.

    Science.gov (United States)

    Heywood, Sarah L; Glavin, Boris A; Beardsley, Ryan P; Akimov, Andrey V; Carr, Michael W; Norman, James; Norton, Philip C; Prime, Brian; Priestley, Nigel; Kent, Anthony J

    2016-01-01

    We demonstrate heterodyne mixing of a 94 GHz millimetre wave photonic signal, supplied by a Gunn diode oscillator, with coherent acoustic waves of frequency ~100 GHz, generated by pulsed laser excitation of a semiconductor surface. The mixing takes place in a millimetre wave Schottky diode, and the intermediate frequency electrical signal is in the 1-12 GHz range. The mixing process preserves all the spectral content in the acoustic signal that falls within the intermediate frequency bandwidth. Therefore this technique may find application in high-frequency acoustic spectroscopy measurements, exploiting the nanometre wavelength of sub-THz sound. The result also points the way to exploiting acoustoelectric effects in photonic devices working at sub-THz and THz frequencies, which could provide functionalities at these frequencies, e.g. acoustic wave filtering, that are currently in widespread use at lower (GHz) frequencies. PMID:27477841

  16. Measurement of small angle based on a (1 0 0) silicon wafer and heterodyne interferometer

    Science.gov (United States)

    Hsieh, Meng-Chang; Lin, Jiun-You; Chen, Yu-Fong; Chang, Chia-Ou

    2016-06-01

    In this paper, a new optical material application and a heterodyne interferometer are proposed for measuring small angles. In the proposed interferometer, the optical material is a (1 0 0) silicon wafer applied to compose a new architecture of small angle sensor. The small angle measurement used the phase difference which is dependent on the incident angle at the silicon wafer surface to deduce the angular variation. The proposed architecture is simple and uses the common path method to compare test and reference signals; thus, small angles can be easily and accurately measured by estimating the phase difference. The experimental results demonstrate the feasibility of this method. The angular resolution and sensitivity levels superior to 7 × 10-5° (1.3 × 10-6 rad) and 150 (deg/deg), respectively, were attainable in a dynamic range of 0.45°.

  17. Heterodyne mixing of millimetre electromagnetic waves and sub-THz sound in a semiconductor device

    Science.gov (United States)

    Heywood, Sarah L.; Glavin, Boris A.; Beardsley, Ryan P.; Akimov, Andrey V.; Carr, Michael W.; Norman, James; Norton, Philip C.; Prime, Brian; Priestley, Nigel; Kent, Anthony J.

    2016-01-01

    We demonstrate heterodyne mixing of a 94 GHz millimetre wave photonic signal, supplied by a Gunn diode oscillator, with coherent acoustic waves of frequency ~100 GHz, generated by pulsed laser excitation of a semiconductor surface. The mixing takes place in a millimetre wave Schottky diode, and the intermediate frequency electrical signal is in the 1–12 GHz range. The mixing process preserves all the spectral content in the acoustic signal that falls within the intermediate frequency bandwidth. Therefore this technique may find application in high-frequency acoustic spectroscopy measurements, exploiting the nanometre wavelength of sub-THz sound. The result also points the way to exploiting acoustoelectric effects in photonic devices working at sub-THz and THz frequencies, which could provide functionalities at these frequencies, e.g. acoustic wave filtering, that are currently in widespread use at lower (GHz) frequencies. PMID:27477841

  18. W-band Heterodyne Receiver Module with 27 K Noise Temperature

    Science.gov (United States)

    Gawande, R.; Reeves, R.; Cleary, K.; Readhead, A. C.; Gaier, T.; Kangaslahti, P.; Samoska, L.; Church, S.; Sieth, M.; Voll, P.; Harris, A.; Lai, R.; Sarkozy, S.

    2012-01-01

    We present noise temperature and gain measurements of a W-band heterodyne module populated with MMIC LNAs designed and fabricated using 35nm InP HEMT process. The module has a WR-10 waveguide input. GPPO connectors are used for the LO input and the I and and Q IF outputs. The module is tested at both ambient (300 K) and cryogenic (25 K) temperatures. At 25 K physical temperature, the module has a noise temperature in the range of 27-45 K over the frequency band of 75-111 GHz. The module gain varies between 15 dB and 27 dB. The band-averaged module noise temperature of 350 K and 33 K were measured over 80-110 GHz for the physical temperature of 300 K and 25 K, respectively. The resulting cooling factor is 10.6.

  19. Fast, high-resolution surface potential measurements in air with heterodyne Kelvin probe force microscopy

    Science.gov (United States)

    Garrett, Joseph L.; Munday, Jeremy N.

    2016-06-01

    Kelvin probe force microscopy (KPFM) adapts an atomic force microscope to measure electric potential on surfaces at nanometer length scales. Here we demonstrate that Heterodyne-KPFM enables scan rates of several frames per minute in air, and concurrently maintains spatial resolution and voltage sensitivity comparable to frequency-modulation KPFM, the current spatial resolution standard. Two common classes of topography-coupled artifacts are shown to be avoidable with H-KPFM. A second implementation of H-KPFM is also introduced, in which the voltage signal is amplified by the first cantilever resonance for enhanced sensitivity. The enhanced temporal resolution of H-KPFM can enable the imaging of many dynamic processes, such as such as electrochromic switching, phase transitions, and device degredation (battery, solar, etc), which take place over seconds to minutes and involve changes in electric potential at nanometer lengths.

  20. Ultrafast chirped optical waveform recorder using referenced heterodyning and a time microscope

    Science.gov (United States)

    Bennett, Corey Vincent

    2011-11-22

    A new technique for capturing both the amplitude and phase of an optical waveform is presented. This technique can capture signals with many THz of bandwidths in a single shot (e.g., temporal resolution of about 44 fs), or be operated repetitively at a high rate. That is, each temporal window (or frame) is captured single shot, in real time, but the process may be run repeatedly or single-shot. This invention expands upon previous work in temporal imaging by adding heterodyning, which can be self-referenced for improved precision and stability, to convert frequency chirp (the second derivative of phase with respect to time) into a time varying intensity modulation. By also including a variety of possible demultiplexing techniques, this process is scalable to recoding continuous signals.

  1. Ultrafast chirped optical waveform recording using referenced heterodyning and a time microscope

    Science.gov (United States)

    Bennett, Corey Vincent

    2010-06-15

    A new technique for capturing both the amplitude and phase of an optical waveform is presented. This technique can capture signals with many THz of bandwidths in a single shot (e.g., temporal resolution of about 44 fs), or be operated repetitively at a high rate. That is, each temporal window (or frame) is captured single shot, in real time, but the process may be run repeatedly or single-shot. This invention expands upon previous work in temporal imaging by adding heterodyning, which can be self-referenced for improved precision and stability, to convert frequency chirp (the second derivative of phase with respect to time) into a time varying intensity modulation. By also including a variety of possible demultiplexing techniques, this process is scalable to recoding continuous signals.

  2. Fast, high-resolution surface potential measurements in air with heterodyne Kelvin probe force microscopy.

    Science.gov (United States)

    Garrett, Joseph L; Munday, Jeremy N

    2016-06-17

    Kelvin probe force microscopy (KPFM) adapts an atomic force microscope to measure electric potential on surfaces at nanometer length scales. Here we demonstrate that Heterodyne-KPFM enables scan rates of several frames per minute in air, and concurrently maintains spatial resolution and voltage sensitivity comparable to frequency-modulation KPFM, the current spatial resolution standard. Two common classes of topography-coupled artifacts are shown to be avoidable with H-KPFM. A second implementation of H-KPFM is also introduced, in which the voltage signal is amplified by the first cantilever resonance for enhanced sensitivity. The enhanced temporal resolution of H-KPFM can enable the imaging of many dynamic processes, such as such as electrochromic switching, phase transitions, and device degredation (battery, solar, etc), which take place over seconds to minutes and involve changes in electric potential at nanometer lengths. PMID:27159082

  3. The use of heterodyne speckle photogrammetry to measure high-temperature strain distributions

    Science.gov (United States)

    Stetson, K. A.

    1983-01-01

    Thermal and mechanical strains have been measured on samples of a common material used in jet engine burner liners, which were heated from room temperature to 870 C and cooled back to 220 C, in a laboratory furnace. The physical geometry of the sample surface was recorded to select temperatures by means of a set of twelve single-exposure specklegrams. Sequential pairs of specklegrams were compared in a heterodyne interferometer which allowed high-precision measurement of differential displacements. Good speckle correlation was observed between the first and last specklegrams also, which showed the durability of the surface microstructure, and permitted a check on accumulated errors. Agreement with calculated thermal expansion was to within a few hundred microstrain over a range of fourteen thousand.

  4. Heterodyne Velocimetry measurements on solids shock driven by high power lasers

    Science.gov (United States)

    Mercier, Patrick; Benier, Jacky; Frugier, Pierre-Antoine; Sollier, Arnaud; Lescoute, Emilen; Cuq-Lelandais, Jean-Paul; Gay, Elise; de Resseguier, Thibaut; Berthe, Laurent; Boustie, Michel; Nivard, Mariette; Claverie, Alain; Rabec Le Gloahec, Marc

    2009-06-01

    A new Heterodyne Velocimeter (PDV) is under development at CEA for high explosive experimentations. Recently, we used it onto metallic target shock driven by high power laser. The aim is to test the ability of this means to reveal the propagation and the effects of shocks into materials, at extremely high strain rate and fast variations into the loading evolution. Spallation and fragmentation experiments carried out on aluminum samples, were performed on the LULI lasers at the Ecole Polytechnique, with both VISAR and HV diagnostics. Comparisons reveal a very good consistency of both experimental results. In addition, HV diagnostic evidence several levels of velocity in the experiment of fragmentation. Interpretation of these measurements is supported by transverse shadowgraphy analysis.

  5. The effect of patch potentials in Casimir force measurements determined by heterodyne Kelvin probe force microscopy

    Science.gov (United States)

    Garrett, Joseph L.; Somers, David; Munday, Jeremy N.

    2015-06-01

    Measurements of the Casimir force require the elimination of the electrostatic force between the surfaces. However, due to electrostatic patch potentials, the voltage required to minimize the total force may not be sufficient to completely nullify the electrostatic interaction. Thus, these surface potential variations cause an additional force, which can obscure the Casimir force signal. In this paper, we inspect the spatially varying surface potential of e-beamed, sputtered, sputtered and annealed, and template stripped gold surfaces with Heterodyne amplitude modulated Kelvin probe force microscopy (HAM-KPFM). It is demonstrated that HAM-KPFM improves the spatial resolution of surface potential measurements compared to amplitude modulated Kelvin probe force microscopy. We find that patch potentials vary depending on sample preparation, and that the calculated pressure can be similar to the pressure difference between Casimir force calculations employing the plasma and Drude models.

  6. Continuous synchronization scheme for TRIUMF KAON Factory Booster and Collector by heterodyne with intermediate frequency

    International Nuclear Information System (INIS)

    Often it arises that several batches of protons must be transferred in box-car fashion from a Booster to Main Ring synchrotron. When the combination (i) large change in kinematic β, (ii) γ-transition close to γ-beam, (iii) small radial aperture confining Δp/ps steering, and (iv) absence of magnetic flat top, occur in the Booster, then conventional phase slip methods of synchronization become infeasible. An alternative is to heterodyne the Booster revolution frequency with an intermediate frequency (of predetermined phase variation) so as to produce a signal equal to a harmonic of the main ring revolution frequency. This allows elaboration of a synchronization control. This paper describes computer modelling of the synchronization technique, as applied to the KAON Factory Booster and Collector, including the effects of error sources and beam-control loops. 4 figs

  7. An accurate 3D inspection system using heterodyne multiple frequency phase-shifting algorithm

    Science.gov (United States)

    Xiao, Zhenzhong; Chee, Oichoo; Asundi, Anand

    This paper presents an accurate 3D inspection system for industrial applications, which uses digital fringe projection technology. The system consists of two CCD cameras and a DLP projector. The mathematical model of the 3D inspection system with 10 distortion parameters for each camera is proposed. A heterodyne multiple frequency phase-shifting algorithm is employed for overcoming the unwrapping problem of phase functions and for a reliable unwrapping procedure. The redundant phase information is used to increase the accuracy of the 3D reconstruction. To demonstrate the effectiveness of our system, a standard sphere was used for testing. The verification test for the 3D inspection systems are based on the VDI standard 2634. The result shows the proposed system can be used for industrial quality inspection with high measurement precision.

  8. A W-Band Heterodyne FMCW Radar Based on TX IQ-Modulation

    Science.gov (United States)

    Feger, Reinhard; Wagner, Christoph; Stelzer, Andreas

    2011-08-01

    In this paper a method to realize a heterodyne frequency-modulated continuous-wave (FMCW) radar is presented. The proposed principle relies on the use of an inphase/quadrature (IQ)-modulator as single-sideband-mixer to shift the frequency of the FMCW-output away from dc. Since in any IQ-modulator phase and amplitude imbalances occur, the effect of these imbalances will be investigated by deriving the corresponding signal model. Based on this analysis, a method to compensate the imbalances by a predistortion of the modulation signal will be derived. The presented method does not require special test signals or additional hardware, but relies on a standard FMCW measurement onto a calibration target. A prototype radar system was built and used in test measurements to verify the proposed principle. The measurement results show that a suppression of unwanted signal components caused by IQ-imbalances better than 45 dB is achievable.

  9. A laser interferometer for measuring straightness and its position based on heterodyne interferometry

    International Nuclear Information System (INIS)

    Not only the magnitude but also the position of straightness errors are of concern to users. However, current laser interferometers used for measuring straightness seldom give the relative position of the straightness error. To solve this problem, a laser interferometer for measuring straightness and its position based on heterodyne interferometry is proposed. The optical configuration of the interferometer is designed and the measurement principle is analyzed theoretically. Two experiments were carried out. The first experiment verifies the validity and repeatability of the interferometer by measuring a linear stage. Also, the second one for measuring a flexure-hinge stage demonstrates that the interferometer is capable of nanometer measurement accuracy. These results show that this interferometer has advantages of simultaneously measuring straightness error and the relative position with high precision, and a compact structure.

  10. Imaging Gold Nanoparticles in Living Cells Environments using Heterodyne Digital Holographic Microscopy

    CERN Document Server

    Warnasooriya, Nilanthi; Bun, Philippe; Tessier, Gilles; Coppey-Moisan, Maite; Desbiolles, Pierre; Atlan, Michael; Abboud, Marie; Gross, Michel

    2009-01-01

    This paper describes an imaging microscopic technique based on heterodyne digital holography where subwavelength-sized gold colloids can be imaged in cell environment. Surface cellular receptors of 3T3 mouse fibroblasts are labeled with 40 nm gold nanoparticles, and the biological specimen is imaged in a total internal reflection configuration with holographic microscopy. Due to a higher scattering efficiency of the gold nanoparticles versus that of cellular structures, accurate localization of a gold marker is obtained within a 3D mapping of the entire sample's scattered field, with a lateral precision of 5 nm and 100 nm in the x,y and in the z directions respectively, demonstrating the ability of holographic microscopy to locate nanoparticles in living cells environments.

  11. Novel concept of interferometric control of the moving coil in watt balance

    OpenAIRE

    Wakim, M; Chassagne, L; Topsu, S; Alayli, Y; Wallerand, JP.; Juncar, P.; Geneves, G

    2007-01-01

    One of the most promising projects for the new definition of the kilogram is the watt balance. It uses a two-mode procedure: static mode and dynamic mode. One of the key points is to control the velocity, the yaw and the pitch of a moving coil during the dynamic mode. We have developed a specific method based on the use of a homemade double pass heterodyne interferometer, a two-level translation stage, and a home-made high frequency phase shifting electronic circuit. However, the commercial h...

  12. Dual-wavelength operation of monolithically integrated arrayed waveguide grating lasers for optical heterodyning

    Science.gov (United States)

    Guzmán M., Robinson C.; Jimenez, Álvaro; Lawniczuk, Katarzyna; Corradi, Antonio; Leijtens, Xaveer J. M.; Bente, Erwin A. J. M.; Carpintero, Guillermo

    2013-05-01

    A cost-effective solution to provide higher data rates in wireless communication system is to push carrier wave frequencies into millimeter wave (MMW) range, where the frequency bands within the E-band and F-band have been allocated. Photonics is a key technology to generate low phase noise signals, offering methods of generating continuous MMW with varying performance in terms of frequency bandwidth, tunability, and stability. Recently, we demonstrated for the first time of our knowledge the generation of a 95-GHz signal by optical heterodyning of two modes from different channels of a monolithically integrated arrayed waveguide grating multi-wavelength laser (AWGL). The device uses an arrayed waveguide grating (AWG) as an intra-cavity filter. With up to 16-channel sources with independent amplifiers and a booster amplifier on the common waveguide, the laser cavity is formed between cleaved facets of the chip. The two wavelengths required for optical heterodyning are generated activating simultaneously two channel SOAs and the Boost amplifier. In this work, we analyze the effect on the dual-wavelength operation of the Boost SOA, which is shared by two wavelengths. Mapping the optical spectrum, sweeping the two channel and Boost bias currents, we show the interaction among the different SOAs two find the regions of dual wavelength operation. The size of dual wavelength operation region depends greatly on the Boost SOA bias level. Initial results of a numerical model of the AWGL will be also presented, in which a digital filter is used to implement the AWG frequency behavior.

  13. First calibration and visible band observations of Khayyam, a Tunable Spatial Heterodyne Spectroscopy (SHS)

    Science.gov (United States)

    Hosseini, S.; Harris, W.; Corliss, J.

    2013-12-01

    We present initial results from observations of wide-field targets using new instrumentation based on an all-reflective spatial heterodyne spectrometer (SHS). SHS instruments are quasi common path two-beam Fourier transform spectrometers that produce 2-D spatial interference patterns without the requirement for moving parts. The utility of SHS comes from its combination of a wide input acceptance angle (0.5-1°), high resolving power (of order ~10^5), compact format, high dynamic range, and relaxed optical tolerances compared with other interferometer designs. This combination makes them extremely useful for velocity resolved for observations of wide field targets from both small and large telescopes. We have constructed both narrow band pass and broadly tunable designs at fixed focal plane facilities on Mt Hamilton and Kitt Peak. This report focuses on the tunable instrument at Mt Hamilton, which is at the focus of the Coudé Auxiliary Telescope (CAT). The CAT provides a test case for on-axis use of SHS, and the impact of the resulting field non-uniformity caused by the spider pattern will be discussed. Observations of several targets will be presented that demonstrate the capabilities of SHS, including comet C/2012 S1 (ISON), Jupiter, and both the day sky and night glow. Raw interferometric data and transformed power spectra will be shown and evaluated in terms of instrumental stability. Khayyam, The Tunable all-reflective Special Heterodyne Spectrometer (SHS) that has being characterized at the Coudé Auxiliary Telescope (CAT) on Mt. Hamilton.

  14. Characteristics and performance of offset phase locked single frequency heterodyned laser systems

    Science.gov (United States)

    Tulchinsky, David A.; Hastings, Alexander S.; Williams, Keith J.

    2016-05-01

    We demonstrate and characterize the performance of two heterodyned optical phase locked loop (PLL) laser systems for use in characterizing photodetector RF frequency response and nonlinearities. Descriptions of PLL circuit parameters for Nd:YAG non-planar ring oscillator lasers at 1064 nm and 1319 nm, and Er ion fiber lasers from 1530 nm to 1565 nm are presented. Both laser systems have piezoelectric transducer wavelength control over the PLL voltage controlled oscillator circuit. Offset frequency phase locking from 1.5 kHz to 51+ GHz is demonstrated. Frequency stability at 10 MHz is measured to be ±50 μHz, limited by the stability of the Rb stabilized crystal oscillator. Phase noise of the phase-locked 1319 nm laser system is discussed where we find that the phase noise is dominated by the input source noise at frequency offsets below 100 Hz and by the laser's RIN noise at frequency offsets > 100 Hz. Comparing nonlinearity data from an InGaAs p-i-n photodiode using both 1319 nm and 1550 nm PLL nonlinearity measurement systems, we find two new separate photodetector nonlinearity mechanisms. Measurements of the harmonic components of a 11 MHz sinusoidal heterodyned optical beat note signal are found to be at or below 1 nW/mW for the second harmonic (at 22 MHz) and at or below 0.25 nW/mW for the 3rd harmonic (at 33 MHz), confirming the nearly pure sinusoidal nature of the optically generated microwave beat note.

  15. Temperature Profile and Surface Pressure Retrieval of Mars’ Atmosphere Using Infrared Heterodyne Spectroscopy

    Science.gov (United States)

    Smith, Ramsey L.; Hewagama, T.; Livengood, T. A.; Fast, K. E.; Kostiuk, T.

    2012-10-01

    Infrared heterodyne spectroscopy of CO2 transitions in the Martian atmosphere was obtained using the Goddard Space Flight Center’s Heterodyne Instrument for Planetary Winds and Composition, HIPWAC, on the NASA Infrared Telescope Facility 3-m telescope, with resolving power of 2.5107. The measured spectra are not fully consistent with temperature profiles for this location and season derived from the Mars Global Surveyor mission (MGS), particularly constraining the pressure and temperature in the deepest part of the troposphere with unambiguous differences between the MGS temperature profile and that required to satisfy the measured emergent spectrum. The temperature information is useful for studying seasonal and global variability, for comparison of results from flight mission results, as well as better profiles for interpreting flight obtained measurements. We will report data collected from our analysis of our high-resolution measurement of 16O12C16O used to develop a temperature profile and surface pressure. CO2 is uniformly mixed in the Martian atmosphere, which makes it an ideal candidate for temperature determination. We are able to collect spectra of the isotopologues of CO2 in the same spectra, which eliminates a source of error for molecular species identification and atmosphere temperature determination. The aforementioned parameters are critical for Martian atmospheric-surface investigations such as isotopologue determination and isotope ratio calculations. For example, an average over measurements acquired at the subsolar point and in the early afternoon at the subsolar latitude yields the terrestrial VSMOW standard, with a minimal difference of 18O = +9±14 ‰. This precision is sufficient to enable a remote investigation of seasonal variations, i.e. due to mass-dependent fractionation in the polar ice cap freeze-sublimate cycle.

  16. Engineering Rules for Optical Generation and Detection of High Speed Wireless Millimeter-wave Band Signals

    DEFF Research Database (Denmark)

    Caballero Jambrina, Antonio; Zibar, Darko; Sambaraju, Rakesh;

    2011-01-01

    We analyze the design requirements for 40 Gbit/s wireless generation and detection in the millimeter-wave band, combining baseband optical I/Q modulation and coherent detection with wireless optical heterodyning generation and single-side band electro-optical modulation....

  17. Vital signs detection radar using low intermediate-frequency architecture and single-sideband transmission

    DEFF Research Database (Denmark)

    Jensen, Brian Sveistrup; Jónasson, Sævar Þór; Johansen, Tom Keinicke; Jensen, Thomas

    This paper presents a continuous wave vital signs detection radar that utilizes a heterodyne transceiver architecture with a 10 MHz intermediate frequency to remove both unwanted DC offsets in the electronic components and the so-called null-detection-points. For successful removal of the latter...

  18. Vital signs detection radar using low intermediate-frequency architecture and single-sideband transmission

    DEFF Research Database (Denmark)

    Jensen, Brian Sveistrup; Jónasson, Sævar Þór; Johansen, Tom Keinicke; Jensen, Thomas

    This paper presents a continuous wave vital signs detection radar that utilizes a heterodyne transceiver architecture with a 10 MHz intermediate frequency to remove both unwanted DC offsets in the electronic components and the so-called null-detection-points. For successful removal of the latter,...

  19. Numerical investigation of multi-beam laser heterodyne measurement with ultra-precision for linear expansion coefficient of metal based on oscillating mirror modulation

    Institute of Scientific and Technical Information of China (English)

    Li Yan-Chao; Wang Chun-Hui; Qu Yang; Gao Long; Cong Hai-Fang; Yang Yan-Ling; Gao Jie; Wang Ao-You

    2011-01-01

    This paper proposes a novel method of multi-beam laser heterodyne measurement for metal linear expansion coefficient. Based on the Doppler effect and heterodyne technology, the information is loaded of length variation to the frequency difference of the multi-beam laser heterodyne signal by the frequency modulation of the oscillating mirror,this method can obtain many values of length variation caused by temperature variation after the multi-beam laser heterodyne signal demodulation simultaneously. Processing these values by weighted-average, it can obtain length variation accurately, and eventually obtain the value of linear expansion coefficient of metal by the calculation. This novel method is used to simulate measurement for linear expansion coefficient of metal rod under different temperatures by MATLAB, the obtained result shows that the relative measurement error of this method is just 0.4%.

  20. Balanced Permutation Codes

    OpenAIRE

    Gabrys, Ryan; Milenkovic, Olgica

    2016-01-01

    Motivated by charge balancing constraints for rank modulation schemes, we introduce the notion of balanced permutations and derive the capacity of balanced permutation codes. We also describe simple interleaving methods for permutation code constructions and show that they approach capacity

  1. Dizziness and Balance

    Science.gov (United States)

    AUDIOLOGY Dizziness and Balance Inform ation Seri es Our balance system helps us walk, run, and move ... known as nystagmus) • Complaints of vertigo or dizziness Audiology Information Series © ASHA 2015 10802 • Balance dysfunction • Difficulty ...

  2. Hot electron bolometer heterodyne receiver with a 4.7-THz quantum cascade laser as a local oscillator

    CERN Document Server

    Kloosterman, Jenna L; Ren, Yuan; Kao, Tsung-Yu; Hovenier, Neils; Gao, Jian-Rong; Klapwijk, Teun M; Hu, Qing; Walker, Christopher K; Reno, John L

    2012-01-01

    We report on a heterodyne receiver designed to observe the astrophysically important neutral atomic oxygen [OI] line at 4.7448 THz. The local oscillator is a third-order distributed feedback Quantum Cascade Laser operating in continuous wave mode at 4.756 THz. A quasi-optical, superconducting NbN hot electron bolometer is used as the mixer. We recorded a double sideband receiver noise temperature (T^DSB_rec) of 815 +/- 12 K, which is ~7 times the quantum noise limit (hf/2kB) and an Allan variance time of 15 s at an effective noise fluctuation bandwidth of 18 MHz. Heterodyne performance was confirmed by measuring a methanol line spectrum.

  3. Frequency bandwidth and conversion loss of a semiconductor heterodyne receiver with phonon cooling of two-dimensional electrons

    International Nuclear Information System (INIS)

    The temperature and concentration dependences of the frequency bandwidth of terahertz heterodyne AlGaAs/GaAs detectors based on hot electron phenomena with phonon cooling of two-dimensional electrons have been measured by submillimeter spectroscopy with a high time resolution. At a temperature of 4.2 K, the frequency bandwidth at a level of 3 dB (f3dB) is varied from 150 to 250 MHz with a change in the concentration ns according to the power law f3dB ∝ ns-0.5 due to the dominant contribution of piezoelectric phonon scattering. The minimum conversion loss of the semiconductor heterodyne detector is obtained in structures with a high carrier mobility (μ > 3 x 105 cm2 V-1 s-1 at 4.2 K).

  4. Thermal structure of Venus' nightside mesosphere as observed by infrared heterodyne spectroscopy at 10 μm

    Science.gov (United States)

    Stangier, Tobias; Hewagama, Tilak; Sornig, Manuela; Sonnabend, Guido; Kostiuk, Theodor; Herrmann, Maren; Livengood, Timothy

    2015-08-01

    Ground-based heterodyne spectroscopy is used to observe the night side of Venus by probing single pressure broadened CO2 absorption lines. From the pressure induced line broadening, the predominant temperature at different altitude layers can be deduced. It is found, that heterodyne spectroscopy is sensitive to probe the mesosphere between ~ 60 km and 90 km with an altitude resolution of ~ 4.5 km. During two observing campaigns in March and May 2012, four different locations on the planet were investigated. Herein, we report on the retrieval of vertical temperature profiles in the nightside atmosphere of Venus. Retrieval of atmospheric parameters is based on a Levenberg-Marquard χ2 optimization that iteratively compares observed data to telluric transmittance corrected Venus' top-of-atmosphere spectra calculated using a radiative transfer algorithm. The deduced profiles are compared to the Venus International Reference Atmosphere and some found to be in satisfactory agreement. Sub-Doppler resolution Infrared heterodyne observations can provide temperature measurements that complement existing sub-mm and space based observations.

  5. Mid-infrared concentration-modulated noise-immune cavity-enhanced optical heterodyne molecular spectroscopy of a continuous supersonic expansion discharge source

    Science.gov (United States)

    Talicska, Courtney N.; Porambo, Michael W.; Perry, Adam J.; McCall, Benjamin J.

    2016-06-01

    Concentration-modulated noise-immune cavity-enhanced optical heterodyne molecular spectroscopy (NICE-OHMS) is implemented for the first time on a continuous gas-flow pinhole supersonic expansion discharge source for the study of cooled molecular ions. The instrument utilizes a continuous-wave optical parametric oscillator easily tunable from 2.5 to 3.9 μm and demonstrates a noise equivalent absorption of ˜1 × 10-9 cm-1. The effectiveness of concentration-modulated NICE-OHMS is tested through the acquisition of transitions in the ν1 fundamental band of HN2+ centered near 3234 cm-1, with a signal-to-noise of ˜40 obtained for the strongest transitions. The technique is used to characterize the cooling abilities of the supersonic expansion discharge source itself, and a Boltzmann analysis determines a rotational temperature of ˜29 K for low rotational states of HN2+. Further improvements are discussed that will enable concentration-modulated NICE-OHMS to reach its full potential for the detection of molecular ions formed in supersonic expansion discharges.

  6. On-chip, self-detected THz dual-comb spectrometer

    CERN Document Server

    Rösch, Markus; Villares, Gustavo; Bosco, Lorenzo; Beck, Mattias; Faist, Jérôme

    2016-01-01

    We present a directly generated on-chip dual-comb source at THz frequencies. The multi-heterodyne beating signal of two free-running THz quantum cascade laser frequency combs is measured electrically using one of the combs as a detector, fully exploiting the unique characteristics of quantum cascade active regions. Up to 30 modes can be detected corresponding to a spectral bandwidth of 630 GHz, being the available bandwidth of the dual comb configuration. The multi-heterodyne signal is used to investigate the equidistance of the comb modes showing an accuracy of $10^{-12}$ at the carrier frequency of 2.5 THz.

  7. Detection of miniband formation in strain-balanced InGaAs/GaAsP quantum well solar cells by using a piezoelectric photothermal spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Aihara, Taketo; Fukuyama, Atsuhiko; Yokoyama, Yuki; Kojima, Michiya; Ikari, Tetsuo [Faculty of Engineering, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192 (Japan); Suzuki, Hidetoshi [Interdisciplinary Research Organization, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192 (Japan); Sugiyama, Masakazu [School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032 (Japan); Nakano, Yoshiaki [Research Center for Advanced Science and Technology, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032 (Japan)

    2014-07-28

    To investigate the effect of the miniband formation on the optical absorption spectrum, we adopted two non-destructive methodologies of piezoelectric photothermal (PPT) and photoreflectance (PR) spectroscopies for strain-balanced InGaAs/GaAsP multiple quantum-well (MQW) and superlattice (SL) structures inserted GaAs p-i-n solar cells. Because the barrier widths of the SL sample were very thin, miniband formations caused by coupling the wave functions between adjacent wells were expected. From PR measurements, a critical energy corresponding to the inter-subband transition between first-order electron and hole subbands was estimated for MQW sample, whereas two critical energies corresponding to the mini-Brillouin-zone center (Γ) and edge (π) were obtained for SL sample. The miniband width was calculated to be 19 meV on the basis of the energy difference between Γ and π. This coincided with the value of 16 meV calculated using the simple Kronig–Penney potential models. The obtained PPT spectrum for the SL sample was decomposed into the excitonic absorption and inter-miniband transition components. The latter component was expressed using the arcsine-like signal rise corresponding to the Γ point in the mini-Brillouin zone that was enhanced by the Sommerfeld factor. The usefulness of the PPT methodology for investigating the inserted MQW and/or SL structure inserted solar cells is clearly demonstrated.

  8. Detection of miniband formation in strain-balanced InGaAs/GaAsP quantum well solar cells by using a piezoelectric photothermal spectroscopy

    International Nuclear Information System (INIS)

    To investigate the effect of the miniband formation on the optical absorption spectrum, we adopted two non-destructive methodologies of piezoelectric photothermal (PPT) and photoreflectance (PR) spectroscopies for strain-balanced InGaAs/GaAsP multiple quantum-well (MQW) and superlattice (SL) structures inserted GaAs p-i-n solar cells. Because the barrier widths of the SL sample were very thin, miniband formations caused by coupling the wave functions between adjacent wells were expected. From PR measurements, a critical energy corresponding to the inter-subband transition between first-order electron and hole subbands was estimated for MQW sample, whereas two critical energies corresponding to the mini-Brillouin-zone center (Γ) and edge (π) were obtained for SL sample. The miniband width was calculated to be 19 meV on the basis of the energy difference between Γ and π. This coincided with the value of 16 meV calculated using the simple Kronig–Penney potential models. The obtained PPT spectrum for the SL sample was decomposed into the excitonic absorption and inter-miniband transition components. The latter component was expressed using the arcsine-like signal rise corresponding to the Γ point in the mini-Brillouin zone that was enhanced by the Sommerfeld factor. The usefulness of the PPT methodology for investigating the inserted MQW and/or SL structure inserted solar cells is clearly demonstrated.

  9. THz Instrumentation for the Herschel Space Observatory's Heterodyne Instrument for Far Infrared

    Science.gov (United States)

    Pearson, J. C.; Mehdi, I.; Ward, J. S.; Maiwald, F.; Ferber, R. R.; Leduc, H. G.; Schlecht, E. T.; Gill, J. J.; Hatch, W. A.; Kawamura, J. H.; Stern, J. A.; Gaier, T. C.; Samoska, L. A.; Weinreb, S.; Bumble, B.; Pukala, D. M.; Javadi, H. H.; Finamore, B. P.; Lin, R. H.; Dengler, R. J.; Velebir, J. R.; Luong, E. M.; Tsang, R.; Peralta, A .; Wells, M.

    2004-01-01

    The Heterodyne Instrument for Far Infrared (HIFI) on ESA's Herschel Space Observatory utilizes a variety of novel RF components in its five SIS receiver channels covering 480-1250 GHz and two HEB receiver channels covering 1410-1910 GHz. The local oscillator unit will be passively cooled while the focal plane unit is cooled by superfluid helium and cold helium vapors. HIFI employs W-band GaAs amplifiers, InP HEMT low noise IF amplifiers, fixed tuned broadband planar diode multipliers, high power W-bapd Isolators, and novel material systems in the SIS mixers. The National Aeronautics and Space Administration through the Jet Propulsion Laboratory is managing the development of the highest frequency (1119-1250 GHz) SIS mixers, the local oscillators oscillators for the three highest frequency receivers as well as W-band power amplifiers, high power W-band isolators, varactor diode devices for all high frequency multipliers and InP HEMT components for all the receiver channels intermediate frequency amplifiers. The NASA developed components represent a significant advancement in the available performance. This paper presents an update of the performance and the current state of development.

  10. Miniaturized, 9-12 micron heterodyne spectrometer with space qualifiable design features

    Science.gov (United States)

    Glenar, D. A.; Mumma, M. J.; Kostiuk, T.; Huffman, H.; Degnan, J.

    1990-01-01

    A demonstration-prototype CO2-laser heterodyne spectrometer operating at 9-12 microns and suitable for long-term space missions is described and illustrated with extensive diagrams, drawings, photographs, and graphs of test performance data. The spectrometer has total volume 0.63 cu m, mass 30 kg, and power requirement 60-70 W, compatible with miniature-class Space Shuttle experiment payload specifications. It comprises three modules: (1) an optical front end with reflecting optics, a 2-GHz BW HgCdTe photomixer, and a 0-2-GHz 40-dB RF preamplifier; (2) a local oscillator with an RF-excited waveguide CO2 laser, a 75-percent-efficiency RF amplifier, a stepper-driven grating mode selector, and an etalon stabilized for over 30,000 h of use; and (3) an RF-filter-bank spectral-line receiver with a 25-MHz RF channel, 1.6-GHz IF spectral coverage, onboard instrument control, a serial link to the host computer, and highly integrated design.

  11. Spatial frequency heterodyne imaging of aqueous phase transitions inside multi-walled carbon nanotubes.

    Science.gov (United States)

    Schunk, F M; Rand, D; Rose-Petruck, C

    2015-12-14

    The evaporation and condensation of water on multi-walled carbon nanotube (MWCNT) surfaces was studied as a function of temperature and time using X-ray spatial frequency heterodyne imaging (SFHI). SFHI is an imaging modality that produces an absorption and scatter image in a single exposure, and has increased sensitivity to variations in electron density relative to more common place X-ray imaging techniques. Differing features exhibited in the temporal scatter intensity profiles recorded during evaporation and condensation revealed the existence of an absorption-desorption hysteresis. Effects on the aforementioned phenomena due to chemical functionalization of the carbon nanotube surfaces were also monitored. The increased interaction potential between the functionalized MWCNT walls and water molecules altered the evaporation event time scale and increased the temperature at which condensation could take place. Theoretical calculations were used to correlate the shape of the observed scatter profiles during condensation to changes in the MWCNT cross section geometry and configuration of the contained water volume. Changes in evaporation time scales with temperature coincided with the boiling point for confined water predicted by the Kelvin equation, indicating that a thermodynamic description of mesoscopic confined water is permissible in some instances. PMID:26549826

  12. Uncertainty Analysis for the Miniaturized Laser Heterodyne Radiometer (mini-LHR)

    Science.gov (United States)

    Clarke, G. B.; Wilson E. L.; Miller, J. H.; Melroy, H. R.

    2014-01-01

    Presented here is a sensitivity analysis for the miniaturized laser heterodyne radiometer (mini-LHR). This passive, ground-based instrument measures carbon dioxide (CO2) in the atmospheric column and has been under development at NASA/GSFC since 2009. The goal of this development is to produce a low-cost, easily-deployable instrument that can extend current ground measurement networks in order to (1) validate column satellite observations, (2) provide coverage in regions of limited satellite observations, (3) target regions of interest such as thawing permafrost, and (4) support the continuity of a long-term climate record. In this paper an uncertainty analysis of the instrument performance is presented and compared with results from three sets of field measurements. The signal-to-noise ratio (SNR) and corresponding uncertainty for a single scan are calculated to be 329.4+/-1.3 by deploying error propagation through the equation governing the SNR. Reported is an absorbance noise of 0.0024 for 6 averaged scans of field data, for an instrument precision of approximately 0.2 ppmv for CO2.

  13. Noncontact photoacoustic tomography of in vivo chicken chorioallantoic membrane based on all-fiber heterodyne interferometry

    Science.gov (United States)

    Eom, Jonghyun; Park, Seong Jun; Lee, Byeong Ha

    2015-10-01

    We present three-dimensional (3-D) in vivo photoacoustic (PA) images of the blood vasculature of a chicken chorioallantoic membrane (CAM) obtained by using a fiber-based noncontact PA tomography system. With a fiber-optic heterodyne interferometer, the system measures the surface displacement of a sample, induced by the PA wave, which overcomes the disadvantage of physical-contact of ultrasonic transducer in a conventional system. The performance of an implemented system is analyzed and its capability of in vivo 3-D bioimaging is presented. At a depth of 2.5 mm in a phantom experiment, the lateral and axial resolutions were measured as 100 and 30 μm, respectively. The lateral resolution became doubled at a depth of 7.0 mm however, interestingly, the axial resolution was not noticeably deteriorated with the depth. With the CAM experiment, performed under the American National Standards Institute laser safety standard condition, blood vessel structures placed as deep as 3.5 mm were clearly recognized.

  14. SuperCam, a 64-pixel heterodyne imaging array for the 870 micron atmospheric window

    CERN Document Server

    Groppi, C; Kulesa, C; Pütz, P; Golish, D; Gensheimer, P; Hedden, A; Bussmann, S; Weinreb, S; Kuiper, T; Kooi, J; Jones, G; Bardin, J; Mani, H S; Lichtenberger, A; Narayanan, G; Groppi, Christopher; Walker, Christopher; Kulesa, Craig; Puetz, Patrick; Golish, Dathon; Gensheimer, Paul; Hedden, Abigail; Bussmann, Shane; Weinreb, Sander; Kuiper, Thomas; Kooi, Jacob; Jones, Glenn; Bardin, Joseph; Mani, Hamdi; Lichtenberger, Arthur; Narayanan, Gopal

    2006-01-01

    We report on the development of SuperCam, a 64 pixel, superheterodyne camera designed for operation in the astrophysically important 870 micron atmospheric window. SuperCam will be used to answer fundamental questions about the physics and chemistry of molecular clouds in the Galaxy and their direct relation to star and planet formation. The advent of such a system will provide an order of magnitude increase in mapping speed over what is now available and revolutionize how observational astronomy is performed in this important wavelength regime. Unlike the situation with bolometric detectors, heterodyne receiver systems are coherent, retaining information about both the amplitude and phase of the incident photon stream. From this information a high resolution spectrum of the incident light can be obtained without multiplexing. SuperCam will be constructed by stacking eight, 1x8 rows of fixed tuned, SIS mixers. The IF output of each mixer will be connected to a low-noise, broadband MMIC amplifier integrated in...

  15. Development and field tests of a narrowband all-reflective spatial heterodyne spectrometer.

    Science.gov (United States)

    Corliss, J B; Harris, W M; Mierkiewicz, E J; Roesler, F L

    2015-10-20

    We describe the design, development, and performance of a narrowband, all-reflective, unaliased spatial heterodyne spectrometer (SHS) that has been tested in observations at the focus of the 1.6 m main telescope of the McMath-Pierce solar telescope on Kitt Peak. The all-reflective SHS described herein is a highly robust common-path Fourier transform spectrometer without moving parts that, over a limited spectral region, combines the large field of view and high resolving power characteristic of interference spectrometers but at substantially reduced instrument size and optical tolerances. The self-scanned region of wavelength space and resolving power of the SHS are determined by the beam size, the diffraction grating groove density, the number of detector elements, and the fixed orientation of a set of pilot mirrors. The results presented here represent the first successful implementation of this reflective SHS design for field use. We discuss concepts behind the unaliased reflective SHS design and report the performance of the instrument when used to observe terrestrial airglow and absorption features, the solar spectrum, and the Jovian spectrum near λ=6300  Å, at the achieved resolving power (R=λ/δλ) of R>100,000. The results confirm that reflective SHS instruments can deliver effective interferometric performance in the visible to the far-ultraviolet wavelengths with commercial optics of moderate surface quality. PMID:26560368

  16. FPGA-Based Smart Sensor for Online Displacement Measurements Using a Heterodyne Interferometer

    Science.gov (United States)

    Vera-Salas, Luis Alberto; Moreno-Tapia, Sandra Veronica; Garcia-Perez, Arturo; de Jesus Romero-Troncoso, Rene; Osornio-Rios, Roque Alfredo; Serroukh, Ibrahim; Cabal-Yepez, Eduardo

    2011-01-01

    The measurement of small displacements on the nanometric scale demands metrological systems of high accuracy and precision. In this context, interferometer-based displacement measurements have become the main tools used for traceable dimensional metrology. The different industrial applications in which small displacement measurements are employed requires the use of online measurements, high speed processes, open architecture control systems, as well as good adaptability to specific process conditions. The main contribution of this work is the development of a smart sensor for large displacement measurement based on phase measurement which achieves high accuracy and resolution, designed to be used with a commercial heterodyne interferometer. The system is based on a low-cost Field Programmable Gate Array (FPGA) allowing the integration of several functions in a single portable device. This system is optimal for high speed applications where online measurement is needed and the reconfigurability feature allows the addition of different modules for error compensation, as might be required by a specific application. PMID:22164040

  17. FISH studies in a girl with sporadic aniridia and an apparently balanced de novo t(11;13(p13;q33 translocation detect a microdeletion involving the WAGR region

    Directory of Open Access Journals (Sweden)

    Llerena Jr. J.C.

    2000-01-01

    Full Text Available Conventional cytogenetic studies on a female infant with sporadic aniridia revealed what appeared to be a balanced de novo t(11;13 (p13;q33 translocation. Fluorescence in situ hybridization (FISH investigations, however, detected the presence of a cryptic 11p13p14 deletion which included the WAGR region and involved approximately 7.5 Mb of DNA, including the PAX6 and WT1 genes. These results account for the patient's aniridia, and place her at high risk for developing Wilms' tumour. The absence of mental retardation in the patient suggests that the position of the distal breakpoint may also help to refine the mental retardation locus in the WAGR contiguous gene syndrome (Wilms', aniridia, genital anomalies and mental retardation.

  18. 100km distributed temperature sensor based on coherent detection of spontaneous Brillouin back-scatter

    OpenAIRE

    Alahbabi, M.; CHO, Y. T.; Newson, T.P.

    2003-01-01

    We report the longest distributed temperature sensor based on microwave heterodyne detection of the frequency of the anti-Stokes Brillouin signal. At a sensing range of 100km, the temperature accuracy was 8degC, with a spatial resolution of 50m.

  19. Human Balance System

    Science.gov (United States)

    ... Rated Nonprofit! Volunteer. Donate. Review. The Human Balance System Good balance is often taken for granted. Good ... soft, slippery, or uneven). Input from the vestibular system Sensory information about motion, equilibrium, and spatial orientation ...

  20. Random walk and balancing

    CERN Document Server

    Borg, F G

    2004-01-01

    Presents a minireview of topics concerned with balancing in quiet (bipedal) standing, and balancing of a stick. In the focus is the apparent stochastic nature of the swaying of the human inverted pendulum.

  1. Skylab water balance analysis

    Science.gov (United States)

    Leonard, J. I.

    1977-01-01

    The water balance of the Skylab crew was analyzed. Evaporative water loss using a whole body input/output balance equation, water, body tissue, and energy balance was analyzed. The approach utilizes the results of several major Skylab medical experiments. Subsystems were designed for the use of the software necessary for the analysis. A partitional water balance that graphically depicts the changes due to water intake is presented. The energy balance analysis determines the net available energy to the individual crewman during any period. The balances produce a visual description of the total change of a particular body component during the course of the mission. The information is salvaged from metabolic balance data if certain techniques are used to reduce errors inherent in the balance method.

  2. Feasibility of tropospheric water vapor profiling using infrared heterodyne differential absorption lidar

    Science.gov (United States)

    Grund, Christian J.; Hardesty, R. Michael; Rye, Barry J.

    1995-04-01

    Continuous, high quality profiles of water vapor, free of systematic bias, and of moderate temporal and spatial resolution, acquired over long periods at low operational and maintenance cost, are fundamental to the success of the ARM CART program. The development and verification of realistic climate model parameterizations for clouds and net radiation balance, and the correction of other CART site sensor observations for interferences due to the presence of water vapor are critically dependent on water vapor profile measurements. Application of profiles acquired with current techniques, have, to date, been limited by vertical resolution and uniqueness of solution (e.g. high resolution infrared (IR) Fourier transform radiometry), poor spatial and temporal coverage and high operating cost (e.g. radiosondes), or diminished daytime performance, lack of eye-safety, and high maintenance cost (e.g. Raman lidar). Recent developments in infrared laser and detector technology make possible compact IR differential absorption lidar (DIAL) systems at eye-safe wavelengths. In the study reported here, we develop DIAL system performance models and examine the potential to solve some of the shortcomings of previous methods using parameterizations representative of current technologies. These models are also applied to diagnose and evaluate other strengths and weaknesses unique to the DIAL method for this application. This work is to continue in the direction of evaluating yet smaller and lower-cost laser diode-based systems for routine monitoring of the lower altitudes using photon counting detection methods. We regard the present report as interim in nature and will update and extend it as a final report at the end of the term of the contract.

  3. Polarization-balanced beamsplitter

    Science.gov (United States)

    Decker, D.E.

    1998-02-17

    A beamsplitter assembly is disclosed that includes several beamsplitter cubes arranged to define a plurality of polarization-balanced light paths. Each polarization-balanced light path contains one or more balanced pairs of light paths, where each balanced pair of light paths includes either two transmission light paths with orthogonal polarization effects or two reflection light paths with orthogonal polarization effects. The orthogonal pairing of said transmission and reflection light paths cancels polarization effects otherwise caused by beamsplitting. 10 figs.

  4. Coaching for Balance.

    Science.gov (United States)

    Larson, Bonnie

    2001-01-01

    Discusses coaching for balance the integration of the whole self: physical (body), intellectual (mind), spiritual (soul), and emotional (heart). Offers four ways to identify problems and tell whether someone is out of balance and four coaching techniques for creating balance. (Contains 11 references.) (JOW)

  5. Investigation of a robust remote heterodyne envelope detector scheme for cost-efficient E-PON / 60 GHz wireless integration.

    OpenAIRE

    Mitchell, J. E.; M. Thakur; Mikroulis, S.

    2014-01-01

    In this work, a simple remote heterodyne envelope detector scheme is proposed employing an O-SSB scheme for application in a converged E-PON/ 60 GHz scenario. The proposed PON-60GHz wireless system topology (Fig. 1) is discussed and an evaluation of this scheme is experimentally demonstrated including i) an OFDM 60 GHz wireless access system using indoor MMF, ordinary DFB lasers & ii) a 60 GHz wireless PON “bridge” using a VCSEL for the E-PON data. In both cases, the envelope detector scheme ...

  6. Spectroscopically in situ traceable heterodyne frequency-scanning interferometry for distances up to 50 m

    International Nuclear Information System (INIS)

    High-resolution saturation spectroscopy of iodine transitions at 637 nm is used to generate physically stable frequency reference markers for an interferometric absolute distance measurement based on frequency-scanning interferometry. Both experiments are performed simultaneously, posing severe challenges to the in principle well-established experimental techniques. The software-based enhancement of the signal-to-noise ratio is discussed in detail, as well as the demodulation and separation of the heterodyne interferometer signals. Verification measurements up to fifty meters indicate a relative measurement uncertainty well below 10−6. (paper)

  7. Fast scanning heterodyne receiver for the measurement of the time evolution of the electron temperature profile on TFTR

    International Nuclear Information System (INIS)

    Two fast scanning heterodyne receivers, swept between 75 to 110 GHz and 110 to 170 GHz in 2 msec every 4 msec, were developed to measure the electron cyclotron emission on the horizontal midplane of the Tokamak Fusion Test Reactor (TFTR) plasma. An absolute, in situ calibration technique enables the determination of the profile of the plasma electron temperature from the cyclotron emission intensity. The 4 msec repetition rate of the receiver allowed the resolution of sawtooth fluctuations of temperature, whose period was 10 to 100 msec, in profiles with central temperatures of 1 to 2.5 keV

  8. Fast scanning heterodyne receiver for the measurement of the time evolution of the electron temperature profile on TFTR

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, G.; Efthimion, P.; McCarthy, M.; Arunasalam, V.; Bitzer, R.; Bryer, J.; Cutler, R.; Fredd, E.; Goldman, M.A.; Kaufman, D.

    1984-06-01

    Two fast scanning heterodyne receivers, swept between 75 to 110 GHz and 110 to 170 GHz in 2 msec every 4 msec, were developed to measure the electron cyclotron emission on the horizontal midplane of the Tokamak Fusion Test Reactor (TFTR) plasma. An absolute, in situ calibration technique enables the determination of the profile of the plasma electron temperature from the cyclotron emission intensity. The 4 msec repetition rate of the receiver allowed the resolution of sawtooth fluctuations of temperature, whose period was 10 to 100 msec, in profiles with central temperatures of 1 to 2.5 keV.

  9. Hot electron bolometer heterodyne receiver with a 4.7-THz quantum cascade laser as a local oscillator

    OpenAIRE

    Kloosterman, J. L.; Hayton, D.J.; Ren, Y; Kao, T.Y.; Hovenier, J. N.; Gao, J. R.; Klapwijk, T. M.; Hu, Q; Walker, C. K.; Reno, J. L.

    2013-01-01

    We report on a heterodyne receiver designed to observe the astrophysically important neutral atomic oxygen [OI] line at 4.7448 THz. The local oscillator is a third-order distributed feedback Quantum Cascade Laser operating in continuous wave mode at 4.741 THz. A quasi-optical, superconducting NbN hot electron bolometer is used as the mixer. We recorded a double sideband receiver noise temperature (T^DSB_rec) of 815 K, which is ~7 times the quantum noise limit (h{\

  10. DYMAC digital electronic balance

    International Nuclear Information System (INIS)

    The Dynamic Materials Accountability (DYMAC) System at LASL integrates nondestructive assay (NDA) instruments with interactive data-processing equipment to provide near-real-time accountability of the nuclear material in the LASL Plutonium Processing Facility. The most widely used NDA instrument in the system is the DYMAC digital electronic balance. The DYMAC balance is a commercial instrument that has been modified at LASL for weighing material in gloveboxes and for transmitting the weight data directly to a central computer. This manual describes the balance components, details the LASL modifications, reviews a DYMAC measurement control program that monitors balance performance, and provides instructions for balance operation and maintenance

  11. The Balanced Company

    DEFF Research Database (Denmark)

    involved in both the creation and recreation of balanced relationships. Chapters in The Balanced Company ask and provide answers to questions about corporately responsible and ethically driven balanced decision making, such as: • How can a company and its stakeholders identify what should be taken into...... changes in their environments. Communication specialists need to make balanced decisions which take the different value systems and assumptions of stakeholders into consideration. Change specialists need to balance the need for continuity and change. Managers need to make balanced decisions about whether...... in consumers' and other stakeholder's eyes. Leaders also have to acknowledge that there are times when organizations have to be taken out of balance, since it is necessary to 'unfreeze' existing relationships in organizations during change. Therefore, there are decision and organizing processes...

  12. Autonomous field measurements of CO2 in the atmospheric column with the miniaturized laser heterodyne radiometer (Mini-LHR)

    Science.gov (United States)

    Melroy, H. R.; Wilson, E. L.; Clarke, G. B.; Ott, L. E.; Mao, J.; Ramanathan, A. K.; McLinden, M. L.

    2015-09-01

    We present column CO2 measurements taken by the passive miniaturized laser heterodyne radiometer (Mini-LHR) at 1611.51 nm at the Mauna Loa Observatory in Hawaii. The Mini-LHR was operated autonomously, during the month of May 2013 at this site, working in tandem with an AERONET sun photometer that measures aerosol optical depth at 15-min intervals during daylight hours. Laser heterodyne radiometry has been used since the 1970s to measure atmospheric gases such as ozone, water vapor, methane, ammonia, chlorine monoxide, and nitrous oxide. This iteration of the technology utilizes distributed feedback lasers to produce a low-cost, small, portable sensor that has potential for global deployment. Applications of this instrument include supplementation of existing monitoring networks to provide denser global coverage, providing validation for larger satellite missions, and targeting regions of carbon flux uncertainty. Also presented here are preliminary retrieval analysis and the performance analysis that demonstrate that the Mini-LHR responds extremely well to changes in the atmospheric absorption.

  13. High-accuracy correction of air refractive index by using two-color heterodyne interferometry of optical frequency combs

    International Nuclear Information System (INIS)

    High-accuracy two-color heterodyne interferometry based on fundamental and second harmonic of frequency combs for air refractive index correction is developed. A monitor interferometer as well as a probe interferometer is constructed to compensate the phase noises and drifts, which are caused by introducing the acousto-optic modulators for heterodyne interferometer, to realize high-accuracy measurement of optical distance. A relative stability of 10−10 to the total length for 500 s is achieved in the measurement of an optical path length difference between two wavelengths. In long-term measurements, the interferometric measurement results and the calculations from empirical equation of air refractive indices are in good agreement with a standard deviation of 4.1 × 10−10 throughout the 10 h period. By applying the two-color method, high-accuracy correction of air refractive index with an uncertainty of 8.9 × 10−8 is achieved during 10 h continuous measurements while the total refractive index changes with a range of 2.0 × 10−6. (paper)

  14. Microwave Instrument for Human Vital Signs Detection and Monitoring

    DEFF Research Database (Denmark)

    Jensen, Brian Sveistrup

    -cost system, emphasis is on the CW type of VSD radars. The signal theory governing both homodyne and heterodyne CW VSD architectures is thoroughly examined. Throughout the discussion it is shown, how heterodyne systems using a low intermediate frequency (IF) can overcome some of the commonly encountered...... problems with homodyne systems, i.e. channel mismatches and DC offsets resulting from hardware imperfections. To verify the theory, a new VSD radar system called the DTU-VISDAM (VItalSigns Detection And Monitoring) has been designed and build. The system together with the implemented signal processing......This work investigates how to design microwave systems for vital signs detection (VSD) and monitoring (i.e. of respiration and heartbeat signals). Typical system types include ultrawideband (UWB) and continuous wave (CW) radars. Due to its ease of implementation and potential for a low-power low...

  15. A 24 GHz integrated SiGe BiCMOS vital signs detection radar front-end

    DEFF Research Database (Denmark)

    Jensen, Brian Sveistrup; Johansen, Tom K.; Zhurbenko, Vitaliy

    2013-01-01

    In this paper a 24 GHz integrated front-end transceiver for vital signs detection (VSD) radars is described. The heterodyne radar transceiver integrates LO buffering and quadrature splitting circuits, up- and down-conversion SSB mixers and two cascaded receiver LNA's. The chip has been manufactured...

  16. Cyclical budget balance measurement

    OpenAIRE

    C. AUDENIS; C. PROST

    2000-01-01

    Government balances are often adjusted for changes in economic activity in order to draw a clearer picture of the underlying fiscal situation and to use this as a guide to fiscal policy analysis. International organisations estimate the cyclical component of economic activity by the current level of the output gap. Using elasticities of tax and public expenditures to GDP, they compute the cyclical part of budget balance. The structural budget balance is defined as the remainder. Our approach ...

  17. Inevitability of Balance Restoration

    OpenAIRE

    Oh, Man S.

    2010-01-01

    Prolonged imbalance between input and output of any element in a living organism is incompatible with life. The duration of imbalance varies, but eventually balance is achieved. This rule applies to any quantifiable element in a compartment of finite capacity. Transient discrepancies occur regularly, but given sufficient time, balance is always achieved, because permanent imbalance is impossible, and the mechanism for eventual restoration of balance is foolproof. The kidney is a central playe...

  18. Identifying Balance in a Balanced Scorecard System

    Science.gov (United States)

    Aravamudhan, Suhanya; Kamalanabhan, T. J.

    2007-01-01

    In recent years, strategic management concepts seem to be gaining greater attention from the academicians and the practitioner's alike. Balanced Scorecard (BSC) concept is one such management concepts that has spread in worldwide business and consulting communities. The BSC translates mission and vision statements into a comprehensive set of…

  19. Conclusion: The balanced company

    DEFF Research Database (Denmark)

    Scheuer, John Damm; Jensen, Inger

    2013-01-01

    This concluding chapter brings together the various research findings of the book "The balanced company - organizing for the 21st Century" and develops a general overview of their implications for our understanding of the balancing processes unfolding in companies and organizations....

  20. Balancing Trust and Control

    DEFF Research Database (Denmark)

    Jagd, Søren

    This paper focuses on the leadership challenge of balancing trust and control. The relation between trust and control has for a long time been a puzzling issue for management researchers. In the paper I first show that there has been a dramatic change in the way the relation between trust and...... control has been conceptualized in trust research. While the relation between trust and control earlier was conceptualized as a more or less stable balance between trust and control, more recent research conceptualizes the relation between trust and control more as a dynamical process that involves an...... ongoing process of balancing the relation between trust and control. Second, taking the departure in the recent conceptualization of the balance between trust and control as an interactive process I discuss the challenges for management in handling this more subtle balancing of trust and control. The...

  1. Mass balance myths

    International Nuclear Information System (INIS)

    In the event of an oil spill at sea, remediation technologies rely on oil spill monitoring and mass balance calculations. The types of oil spills that require knowledge of mass-balance include weathering studies, dispersant-effectiveness testing, measurement of response effectiveness and damage assessment. Non-destructive and non-interfering measuring methods are needed to find components of the mass balance equation such as temporal and spatial distribution of the oil thickness, and the temporal and spatial distribution of oil concentration in the sub-surface plume. The main challenge is the variation in the size scale of laboratory and open ocean measurements. Most large scale oil-spill experiments do not have scientific credibility because there are few situations in which all the oil in the system is accounted for. While some components are accurately accounted for, others ignore mass balance, or the range of measurements is not sufficient to allow for computation of mass balance. 48 refs

  2. Real-time Optical Detection of Single Human and Bacterial Viruses Based on Dark-field Interferometry

    OpenAIRE

    Mitra, Anirban; Ignatovich, Filipp; Novotny, Lukas

    2011-01-01

    The rapid and sensitive detection and characterization of human viruses and bacteriophage is extremely important in a variety of fields, such as medical diagnostics, immunology and vaccine research, and environmental contamination and quality control. We introduce an optical detection scheme for real-time and label-free detection of human viruses and bacteriophage as small as ~ 24 nm in radius. Combining the advantages of heterodyne interferometry and dark-field microscopy, this label-free me...

  3. An All-Solid-State, Room-Temperature, Heterodyne Receiver for Atmospheric Spectroscopy at 1.2 THz

    Science.gov (United States)

    Siles, Jose V.; Mehdi, Imran; Schlecht, Erich T.; Gulkis, Samuel; Chattopadhyay, Goutam; Lin, Robert H.; Lee, Choonsup; Gill, John J.; Thomas, Bertrand; Maestrini, Alain E.

    2013-01-01

    Heterodyne receivers at submillimeter wavelengths have played a major role in astrophysics as well as Earth and planetary remote sensing. All-solid-state heterodyne receivers using both MMIC (monolithic microwave integrated circuit) Schottky-diode-based LO (local oscillator) sources and mixers are uniquely suited for long-term planetary missions or Earth climate monitoring missions as they can operate for decades without the need for any active cryogenic cooling. However, the main concern in using Schottky-diode-based mixers at frequencies beyond 1 THz has been the lack of enough LO power to drive the devices because 1 to 3 mW are required to properly pump Schottky diode mixers. Recent progress in HEMT- (high-electron-mobility- transistor) based power amplifier technology, with output power levels in excess of 1 W recently demonstrated at W-band, as well as advances in MMIC Schottky diode circuit technology, have led to measured output powers up to 1.4 mW at 0.9 THz. Here the first room-temperature tunable, all-planar, Schottky-diode-based receiver is reported that is operating at 1.2 THz over a wide (˜20%) bandwidth. The receiver front-end (see figure) consists of a Schottky-diode-based 540 to 640 GHz multiplied LO chain (featuring a cascade of W-band power amplifiers providing around 120 to 180 mW at W-band), a 200-GHz MMIC frequency doubler, and a 600-GHz MMIC frequency tripler, plus a biasable 1.2-THz MMIC sub-harmonic Schottky-diode mixer. The LO chain has been designed, fabricated, and tested at JPL and provides around 1 to 1.5 mW at 540 o 640 GHz. The sub-harmonic mixer consists of two Schottky diodes on a thin GaAs membrane in an anti-parallel configuration. An integrated metal insulator metal (MIM) capacitor has been included on-chip to allow dc bias for the Schottky diodes. A bias voltage of around 0.5 V/diode is necessary to reduce the LO power required down to the 1 to 1.5 mW available from the LO chain. The epilayer thickness and doping profiles have

  4. Coherent demodulation of microwave signals by using optical heterodyne technique with applications to point to point indoor wireless communications systems

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Juarez, A; Gomez-Colin, M R; Rojas-Hernandez, A G [Universidad de Sonora (Mexico); Zaldivar-Huerta, I E; Aguayo-Rodriguez, G [Instituto Nacional de Astrofisica, Optica y Electronica (Mexico); Rodriguez-Asomoza, J, E-mail: agarcia@cifus.uson.mx [Universidad de las Americas-Puebla (Mexico)

    2011-01-01

    An optical communications system using a couple microstrip antennas for distributing point to point analog TV with coherent demodulation based on optical heterodyne in close vicinity is reported in this paper. In the proposed experimental setup, two optical waves at different wavelengths are mixed and applied to a photodetector. Then a beat signal with a frequency equivalent to the spacing of the two wavelengths is obtained at the output of the photodetector. This signal corresponds to a microwave signal located at 1.25 GHz, which it is used as a microwave carrier in the transmitter and as a local oscillator in the receiver of our optical communication system. The feasibility of this technique is demonstrated transmitting a TV signal of 66-72 MHz.

  5. Two color multichannel heterodyne interferometer set up for high spatial resolution electron density profile measurements in TJ-II

    International Nuclear Information System (INIS)

    A high spatial resolution two color [CO2, λ=10.6 μm/Nd:YAG (Nd:YAG denotes neodymium-doped yttrium aluminum garnet), and λ=1.064 μm] expanded-beam multichannel heterodyne interferometer has been installed on the TJ-II stellarator. Careful design of the optical system has allowed complete control on the evolution of both Gaussian beams along the interferometer, as well as the evaluation and optimization of the spatial resolution to be expected in the measurements. Five CO2 (measurement) channels and three Nd:YAG (vibration compensation) channels have been used to illuminate the plasma with a probe beam of 100 mm size. An optimum interpolation method has been applied to recover both interferometric phasefronts prior to mechanical vibration subtraction. The first results of the installed diagnostic are presented in this paper.

  6. Frequency stabilization of a 1083 nm fiber laser to 4He transition lines with optical heterodyne saturation spectroscopies

    International Nuclear Information System (INIS)

    Two kinds of optical heterodyne saturation spectroscopies, namely, frequency modulation spectroscopy (FMS) and modulation transfer spectroscopy (MTS), are demonstrated for locking a fiber laser to the transition lines of metastable 4He atoms around 1083 nm. The servo-loop error signals of FMS and MTS for stabilizing laser frequency are optimized by studying the dependence of the peak-to-peak amplitude and slope on the optical power of pump and probe beams. A comparison of the stabilization performances of FMS/MTS and polarization spectroscopy (PS) is presented, which shows that MTS exhibits relatively superior performance with the least laser frequency fluctuation due to its flat-background dispersive signal, originated from the four-wave mixing process. The Allan deviation of the stabilized laser frequency is 5.4 × 10−12@100 s with MTS for data acquired in 1000 s, which is sufficiently applicable for fields like laser cooling, optical pumping, and optical magnetometry

  7. Coherent demodulation of microwave signals by using optical heterodyne technique with applications to point to point indoor wireless communications systems

    International Nuclear Information System (INIS)

    An optical communications system using a couple microstrip antennas for distributing point to point analog TV with coherent demodulation based on optical heterodyne in close vicinity is reported in this paper. In the proposed experimental setup, two optical waves at different wavelengths are mixed and applied to a photodetector. Then a beat signal with a frequency equivalent to the spacing of the two wavelengths is obtained at the output of the photodetector. This signal corresponds to a microwave signal located at 1.25 GHz, which it is used as a microwave carrier in the transmitter and as a local oscillator in the receiver of our optical communication system. The feasibility of this technique is demonstrated transmitting a TV signal of 66-72 MHz.

  8. A Comparison of Delayed Self-Heterodyne Interference Measurement of Laser Linewidth Using Mach-Zehnder and Michelson Interferometers

    Directory of Open Access Journals (Sweden)

    Simon Fleming

    2011-09-01

    Full Text Available Linewidth measurements of a distributed feedback (DFB fibre laser are made using delayed self heterodyne interferometry (DHSI with both Mach-Zehnder and Michelson interferometer configurations. Voigt fitting is used to extract and compare the Lorentzian and Gaussian linewidths and associated sources of noise. The respective measurements are wL (MZI = (1.6 ± 0.2 kHz and wL (MI = (1.4 ± 0.1 kHz. The Michelson with Faraday rotator mirrors gives a slightly narrower linewidth with significantly reduced error. This is explained by the unscrambling of polarisation drift using the Faraday rotator mirrors, confirmed by comparing with non-rotating standard gold coated fibre end mirrors.

  9. Analysis of the accuracy of the inverse problem solution for a differential heterodyne microscope as applied to rectangular plasmonic waveguides

    Science.gov (United States)

    Akhmedzhanov, I. M.; Baranov, D. V.; Zolotov, E. M.

    2016-06-01

    The existence, uniqueness, and stability of the inverse problem solution for a scanning differential heterodyne microscope as applied to rectangular plasmonic waveguides have been analyzed. The consideration is based on an algorithm using a trial-and-error method that we proposed previously to characterize plasmonic waveguides with a triangular profile. The error of the inverse problem (IP) solution is calculated as dependent on the initial data and with allowance for their errors. Instability domains are found for the IP solution, where the solution error sharply increases. It is shown that the instability domains can be eliminated and the accuracy of the IP solution can be significantly improved in the entire range of initial data by taking initial data in the form of two phase responses of the microscope at different wavelengths.

  10. Measurement method for roll angular displacement with a high resolution by using diffraction gratings and a heterodyne interferometer

    International Nuclear Information System (INIS)

    The roll angle measurement is difficult to be achieved directly using a typical commercial interferometer due to its low sensitivity in axial direction, where the axial direction is orthogonal to the plane of the roll angular displacement. A roll angle measurement method combined diffraction gratings with a laser heterodyne interferometer is discussed in this paper. The diffraction grating placed in the plane of a roll angular displacement and the interferometer arranged in the plane's orthogonal direction, constitute the measurement pattern for the roll angle with high resolution. The roll angular displacement, considered as the linear, can be tested precisely when the corresponding angle is very small. Using the proposed method, the angle roll measurement obtains the high resolution of 0.002″. Experiment has proved its feasibility and practicability

  11. Design and characterization of a 32-channel heterodyne radiometer for electron cyclotron emission measurements on experimental advanced superconducting tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Han, X.; Liu, X.; Liu, Y., E-mail: liuyong@ipp.ac.cn; Li, E. Z.; Hu, L. Q.; Gao, X. [Institution of Plasma Physics, Chinese Academy of Sciences, P. O. Box 1126, Hefei, Anhui 230031 (China); Domier, C. W.; Luhmann, N. C. [Department of Electrical and Computer Engineering, University of California, Davis, California 95616 (United States)

    2014-07-15

    A 32-channel heterodyne radiometer has been developed for the measurement of electron cyclotron emission (ECE) on the experimental advanced superconducting tokamak (EAST). This system collects X-mode ECE radiation spanning a frequency range of 104–168 GHz, where the frequency coverage corresponds to a full radial coverage for the case with a toroidal magnetic field of 2.3 T. The frequency range is equally spaced every 2 GHz from 105.1 to 167.1 GHz with an RF bandwidth of ∼500 MHz and the video bandwidth can be switched among 50, 100, 200, and 400 kHz. Design objectives and characterization of the system are presented in this paper. Preliminary results for plasma operation are also presented.

  12. Metal-oxide-metal point contact junction detectors. [detection mechanism and mechanical stability

    Science.gov (United States)

    Baird, J.; Havemann, R. H.; Fults, R. D.

    1973-01-01

    The detection mechanism(s) and design of a mechanically stable metal-oxide-metal point contact junction detector are considered. A prototype for a mechanically stable device has been constructed and tested. A technique has been developed which accurately predicts microwave video detector and heterodyne mixer SIM (semiconductor-insulator-metal) diode performance from low dc frequency volt-ampere curves. The difference in contact potential between the two metals and geometrically induced rectification constitute the detection mechanisms.

  13. Active balance system and vibration balanced machine

    Science.gov (United States)

    Qiu, Songgang (Inventor); Augenblick, John E. (Inventor); Peterson, Allen A. (Inventor); White, Maurice A. (Inventor)

    2005-01-01

    An active balance system is provided for counterbalancing vibrations of an axially reciprocating machine. The balance system includes a support member, a flexure assembly, a counterbalance mass, and a linear motor or an actuator. The support member is configured for attachment to the machine. The flexure assembly includes at least one flat spring having connections along a central portion and an outer peripheral portion. One of the central portion and the outer peripheral portion is fixedly mounted to the support member. The counterbalance mass is fixedly carried by the flexure assembly along another of the central portion and the outer peripheral portion. The linear motor has one of a stator and a mover fixedly mounted to the support member and another of the stator and the mover fixedly mounted to the counterbalance mass. The linear motor is operative to axially reciprocate the counterbalance mass.

  14. CHIMPS: the 13CO/C18O (J = 3 → 2) Heterodyne Inner Milky Way Plane Survey

    Science.gov (United States)

    Rigby, A. J.; Moore, T. J. T.; Plume, R.; Eden, D. J.; Urquhart, J. S.; Thompson, M. A.; Mottram, J. C.; Brunt, C. M.; Butner, H. M.; Dempsey, J. T.; Gibson, S. J.; Hatchell, J.; Jenness, T.; Kuno, N.; Longmore, S. N.; Morgan, L. K.; Polychroni, D.; Thomas, H.; White, G. J.; Zhu, M.

    2016-03-01

    We present the 13CO/C18O (J = 3 → 2) Heterodyne Inner Milky Way Plane Survey (CHIMPS) which has been carried out using the Heterodyne Array Receiver Program on the 15 m James Clerk Maxwell Telescope (JCMT) in Hawaii. The high-resolution spectral survey currently covers |b| ≤ 0.5° and 28° ≲ l ≲ 46°, with an angular resolution of 15 arcsec in 0.5 km s-1 velocity channels. The spectra have a median rms of ˜0.6 K at this resolution, and for optically thin gas at an excitation temperature of 10 K, this sensitivity corresponds to column densities of NH2 ˜ 3 × 1020 cm-2 and NH2 ˜ 4 × 1021 cm-2 for 13CO and C18O, respectively. The molecular gas that CHIMPS traces is at higher column densities and is also more optically thin than in other publicly available CO surveys due to its rarer isotopologues, and thus more representative of the three-dimensional structure of the clouds. The critical density of the J = 3 → 2 transition of CO is ≳104 cm-3 at temperatures of ≤20 K, and so the higher density gas associated with star formation is well traced. These data complement other existing Galactic plane surveys, especially the JCMT Galactic Plane Survey which has similar spatial resolution and column density sensitivity, and the Herschel infrared Galactic Plane Survey. In this paper, we discuss the observations, data reduction and characteristics of the survey, presenting integrated-emission maps for the region covered. Position-velocity diagrams allow comparison with Galactic structure models of the Milky Way, and while we find good agreement with a particular four-arm model, there are some significant deviations.

  15. Load Balancing Scientific Applications

    Energy Technology Data Exchange (ETDEWEB)

    Pearce, Olga Tkachyshyn [Texas A & M Univ., College Station, TX (United States)

    2014-12-01

    The largest supercomputers have millions of independent processors, and concurrency levels are rapidly increasing. For ideal efficiency, developers of the simulations that run on these machines must ensure that computational work is evenly balanced among processors. Assigning work evenly is challenging because many large modern parallel codes simulate behavior of physical systems that evolve over time, and their workloads change over time. Furthermore, the cost of imbalanced load increases with scale because most large-scale scientific simulations today use a Single Program Multiple Data (SPMD) parallel programming model, and an increasing number of processors will wait for the slowest one at the synchronization points. To address load imbalance, many large-scale parallel applications use dynamic load balance algorithms to redistribute work evenly. The research objective of this dissertation is to develop methods to decide when and how to load balance the application, and to balance it effectively and affordably. We measure and evaluate the computational load of the application, and develop strategies to decide when and how to correct the imbalance. Depending on the simulation, a fast, local load balance algorithm may be suitable, or a more sophisticated and expensive algorithm may be required. We developed a model for comparison of load balance algorithms for a specific state of the simulation that enables the selection of a balancing algorithm that will minimize overall runtime.

  16. Feasibility of tropospheric water vapor profiling using infrared heterodyne differential absorption lidar

    Energy Technology Data Exchange (ETDEWEB)

    Grund, C.J.; Hardesty, R.M. [National Oceanic and Atmospheric Administration Environmental Technology Laboratoy, Boulder, CO (United States); Rye, B.J. [Univ. of Colorado, Boulder, CO (United States)

    1996-04-01

    The development and verification of realistic climate model parameterizations for clouds and net radiation balance and the correction of other site sensor observations for interferences due to the presence of water vapor are critically dependent on water vapor profile measurements. In this study, we develop system performance models and examine the potential of infrared differential absoroption lidar (DIAL) to determine the concentration of water vapor.

  17. Energy balance measurement

    DEFF Research Database (Denmark)

    Dhurandhar, N V; Schoeller, D; Brown, A W;

    2015-01-01

    Energy intake (EI) and physical activity energy expenditure (PAEE) are key modifiable determinants of energy balance, traditionally assessed by self-report despite its repeated demonstration of considerable inaccuracies. We argue here that it is time to move from the common view that self......-reports of EI and PAEE are imperfect, but nevertheless deserving of use, to a view commensurate with the evidence that self-reports of EI and PAEE are so poor that they are wholly unacceptable for scientific research on EI and PAEE. While new strategies for objectively determining energy balance are in their...... of energy balance....

  18. Improving Balance Function Using Low Levels of Electrical Stimulation of the Balance Organs

    Science.gov (United States)

    Bloomberg, Jacob; Reschke, Millard; Mulavara, Ajitkumar; Wood, Scott; Serrador, Jorge; Fiedler, Matthew; Kofman, Igor; Peters, Brian T.; Cohen, Helen

    2012-01-01

    Crewmembers returning from long-duration space flight face significant challenges due to the microgravity-induced inappropriate adaptations in balance/ sensorimotor function. The Neuroscience Laboratory at JSC is developing a method based on stochastic resonance to enhance the brain s ability to detect signals from the balance organs of the inner ear and use them for rapid improvement in balance skill, especially when combined with balance training exercises. This method involves a stimulus delivery system that is wearable/portable providing imperceptible electrical stimulation to the balance organs of the human body. Stochastic resonance (SR) is a phenomenon whereby the response of a nonlinear system to a weak periodic input signal is optimized by the presence of a particular non-zero level of noise. This phenomenon of SR is based on the concept of maximizing the flow of information through a system by a non-zero level of noise. Application of imperceptible SR noise coupled with sensory input in humans has been shown to improve motor, cardiovascular, visual, hearing, and balance functions. SR increases contrast sensitivity and luminance detection; lowers the absolute threshold for tone detection in normal hearing individuals; improves homeostatic function in the human blood pressure regulatory system; improves noise-enhanced muscle spindle function; and improves detection of weak tactile stimuli using mechanical or electrical stimulation. SR noise has been shown to improve postural control when applied as mechanical noise to the soles of the feet, or when applied as electrical noise at the knee and to the back muscles.

  19. Keeping Your Balance

    Science.gov (United States)

    ... or problems with balance. Sometimes your doctor or physical therapist can reposition the crystals in your ear and ... Adherence Calcium/Vitamin D Nutrition Overall Health Fractures/Fall Prevention Exercise/Safe Movement Safe Movement & Exercise Videos ...

  20. National Energy Balance - 1984

    International Nuclear Information System (INIS)

    The National Energy Balance - 1984 shows energy fluxes of several primary and secondary energy sources, since the productions to final consumption in the main economic sectors, since 1973 to 1983. (E.G.)

  1. National Energy Balance - 1985

    International Nuclear Information System (INIS)

    The National Energy Balance - 1985 shows energy fluxes of several primary and secondary energy sources, since the production to the final consumption in the main economic sectors, since 1974 to 1984 (E.G.)

  2. National Energy Balance-1987

    International Nuclear Information System (INIS)

    The National Energy Balance - 1987 showns energy fluxes of several primary and secondary energy sources, since the production to final consumption in the main economic sectors, since 1971 to 1986. (E.G.)

  3. Detailed balance and entanglement

    International Nuclear Information System (INIS)

    We study a connection between quantum detailed balance, which is a concept of importance in statistical mechanics, and entanglement. We also explore how this connection fits into thermofield dynamics. (paper)

  4. Balance Disorders (For Parents)

    Science.gov (United States)

    ... usually used on infants and young children. electronystagmogram (ENG). To assess balance, electrodes are placed around the ... videonystagmography (VNG). This test is similar to an ENG, only the child has to focus on the ...

  5. Balance costs for windpower

    OpenAIRE

    Skaflestad, Stig

    2009-01-01

    Wind power scheduling is subject to high forecast uncertainty compared to the dominant Norwegian energy source, hydro power. The regulating market, also known as the balance market, is a market solution for optimal operation of the Nordic power system, putting a price on schedule deviations. Schedules, or production/consumption plans, are collected daily, 12 hours prior to delivery by the system operator Statnett. Wind power is especially vulnerable to balance costs due to the relatively high...

  6. Selectively Balancing Unit Vectors

    OpenAIRE

    Blokhuis, Aart; Chen, Hao

    2016-01-01

    A set $U$ of unit vectors is selectively balancing if one can find two disjoint subsets $U^+$ and $U^-$, not both empty, such that the Euclidean distance between the sum of $U^+$ and the sum of $U^-$ is smaller than $1$. We prove that, to guarantee a selectively balancing set, $n \\log n$ unit vectors suffice for sufficiently large $n$, but $\\tfrac{1}{23} n \\log n$ unit vectors won't be enough for infinitely many $n$.

  7. Greenland Ice Sheet Mass Balance

    Science.gov (United States)

    Reeh, N.

    1984-01-01

    Mass balance equation for glaciers; areal distribution and ice volumes; estimates of actual mass balance; loss by calving of icebergs; hydrological budget for Greenland; and temporal variations of Greenland mass balance are examined.

  8. Balances instruments, manufacturers, history

    CERN Document Server

    Robens, Erich; Kiefer, Susanne

    2014-01-01

    The book deals mainly with direct mass determination by means of a conventional balances. It covers the history of the balance from the beginnings in Egypt earlier than 3000 BC to recent developments. All balance types are described with emphasis on scientific balances. Methods of indirect mass determination, which are applied to very light objects like molecules and the basic particles of matter and celestial bodies, are included.  As additional guidance, today’s manufacturers are listed and the profile of important companies is reviewed. Several hundred photographs, reproductions and drawings show instruments and their uses. This book includes commercial weighing instruments for merchandise and raw materials in workshops as well as symbolic weighing in the ancient Egyptian’s ceremony of ‘Weighing of the Heart’, the Greek fate balance, the Roman  Justitia, Juno Moneta and Middle Ages scenes of the Last Judgement with Jesus or St. Michael and of modern balances. The photographs are selected from the...

  9. Watt and joule balances

    Science.gov (United States)

    Robinson, Ian A.

    2014-04-01

    The time is fast approaching when the SI unit of mass will cease to be based on a single material artefact and will instead be based upon the defined value of a fundamental constant—the Planck constant—h . This change requires that techniques exist both to determine the appropriate value to be assigned to the constant, and to measure mass in terms of the redefined unit. It is important to ensure that these techniques are accurate and reliable to allow full advantage to be taken of the stability and universality provided by the new definition and to guarantee the continuity of the world's mass measurements, which can affect the measurement of many other quantities such as energy and force. Up to now, efforts to provide the basis for such a redefinition of the kilogram were mainly concerned with resolving the discrepancies between individual implementations of the two principal techniques: the x-ray crystal density (XRCD) method [1] and the watt and joule balance methods which are the subject of this special issue. The first three papers report results from the NRC and NIST watt balance groups and the NIM joule balance group. The result from the NRC (formerly the NPL Mk II) watt balance is the first to be reported with a relative standard uncertainty below 2 × 10-8 and the NIST result has a relative standard uncertainty below 5 × 10-8. Both results are shown in figure 1 along with some previous results; the result from the NIM group is not shown on the plot but has a relative uncertainty of 8.9 × 10-6 and is consistent with all the results shown. The Consultative Committee for Mass and Related Quantities (CCM) in its meeting in 2013 produced a resolution [2] which set out the requirements for the number, type and quality of results intended to support the redefinition of the kilogram and required that there should be agreement between them. These results from NRC, NIST and the IAC may be considered to meet these requirements and are likely to be widely debated

  10. Balanced Integrated Regulatory Oversight

    International Nuclear Information System (INIS)

    Reactor safety, protecting the public health and safety, and protecting the environment must always be the nuclear regulator's top priorities. Enabling the use of nuclear power for the benefit of society, while protecting the public and the environment requires the regulator to balance many factors. In addition, the regulator is only one part of the overall government that must consider many factors as it carries out its societal responsibilities. Some of the factors that must be balanced and the practical impacts on how the regulator carries out its responsibilities will be addressed. The first International Conference on Effective Regulatory Systems, held in Moscow, Russian Federation, in 2006, focused on safety and security challenges with a goal of improving regulatory effectiveness through cooperation and sharing of information and best practices. The challenge of meeting both safety and security objectives is one example of potentially competing programmes that must be balanced. Other balances that must be evaluated include the benefits of safety improvements compared to the cost of implementation, the use of deterministic and probabilistic approaches, communication openness balanced with the protection of information that could be used for detrimental purposes, and timeliness of regulatory decision making balanced with the need to perform quality work in support of oversight responsibilities. A balanced and integrated approach to regulatory oversight is vital to ensuring that the regulatory body remains effective in its mission to enable the use of nuclear power while protecting the public and the environment. This concept is applicable to nations beginning a nuclear programme as well as established and experienced regulatory bodies. (author)

  11. Quantitative imaging of nanometric optical path length modulations by time-averaged heterodyne holography in coherent frequency-division multiplexing regime

    CERN Document Server

    Bruno, Francois; Lesaffre, Max; Verrier, Nicolas; Atlan, Michael

    2013-01-01

    We report a demonstration of amplitude and phase imaging of out-of-plane sinusoidal vibration at nanometer scales with a heterodyne holographic interferometer. Time-averaged holograms of a phase-modulated optical field are recorded with an exposure time much longer than the modulation period. Optical heterodyning, a frequency-conversion process aimed at shifting a given radiofrequency optical side band in the sensor bandwidth, is performed with an off-axis and frequency-shifted optical local oscillator. The originality of the proposed method is to make use of a multiplexed local oscillator to address several optical side bands into the temporal bandwidth of the sensor array. This process is called coherent frequency-division multiplexing. It enables simultaneous recording and pixel-to-pixel division of two side band holograms, which permits quantitative mapping of the modulation depth of local optical path lengths yielding small optical phase modulations. Additionally, a linear frequency chirp ensures the ret...

  12. Automatic force balance calibration system

    Science.gov (United States)

    Ferris, Alice T.

    1995-05-01

    A system for automatically calibrating force balances is provided. The invention uses a reference balance aligned with the balance being calibrated to provide superior accuracy while minimizing the time required to complete the calibration. The reference balance and the test balance are rigidly attached together with closely aligned moment centers. Loads placed on the system equally effect each balance, and the differences in the readings of the two balances can be used to generate the calibration matrix for the test balance. Since the accuracy of the test calibration is determined by the accuracy of the reference balance and current technology allows for reference balances to be calibrated to within +/-0.05% the entire system has an accuracy of +/-0.2%. The entire apparatus is relatively small and can be mounted on a movable base for easy transport between test locations. The system can also accept a wide variety of reference balances, thus allowing calibration under diverse load and size requirements.

  13. Polarization-independent operation of an acousto-optical device at the transmit end of a single-laser transmission system using self-heterodyning

    Science.gov (United States)

    Olivier, L.; Rocks, M.

    1991-03-01

    This paper describes the way in which a new integrated acousto-optical LiNbO 3 device combining the three functions of an electro-optical phase modulator, an acousto-optical TE/TM or TM/TE mode converter and an acousto-optical frequency shifter can be operated in a polarization-independent manner as a transmitter unit in a single-laser transmission system using self-heterodyning.

  14. Design and calibration of a two-channel low-noise heterodyne receiver for use in a CO2 laser Thomson scattering alpha particle diagnostic

    International Nuclear Information System (INIS)

    A dual channel low noise heterodyne receiver has been constructed as part of a development effort to build a carbon dioxide laser based Thomson scattering alpha particle diagnostic for a burning plasma experiment. The receiver employs two wide bandwidth (>1 GHz) HgCdTe photovoltaic mixers followed by low noise IF amplifiers. A noise equivalent power of less than 3.0 /times/ 10-20 WHz has been demonstrated. Design details and calibration methods are described. 8 refs

  15. The cryogenic balance design and balance calibration methods

    Science.gov (United States)

    Ewald, B.; Polanski, L.; Graewe, E.

    1992-07-01

    The current status of a program aimed at the development of a cryogenic balance for the European Transonic Wind Tunnel is reviewed. In particular, attention is given to the cryogenic balance design philosophy, mechanical balance design, reliability and accuracy, cryogenic balance calibration concept, and the concept of an automatic calibration machine. It is shown that the use of the automatic calibration machine will improve the accuracy of calibration while reducing the man power and time required for balance calibration.

  16. Finding Your Balance

    CERN Document Server

    (CCL), Center for Creative Leadership; Patterson, Gordon

    2011-01-01

    Balance isn't an issue of time, but an issue of choice. It's about living your values by aligning your behavior with what you believe is really important. Aligning your behavior with your values is much like any other developmental experience; the basic process involves assessment, challenge, and support. You need to determine where you are, define where you want to go, and then put into place the tools you need to get there.Balance is about more than how you spend your time. It's about how you live your life. It's about recognizing that you have control over the choices you make and aligning

  17. Getting the balance right

    International Nuclear Information System (INIS)

    This 8 page leaflet is published by the Nuclear Electricity Information Group (NEIG) which is made up of eight different bodies working within the nuclear industry. It aims to present a balanced outline of the facts needed to form an opinion about energy policy in the UK. It looks at the price of electricity, other sources of electricity, (oil and coal, solar power, wind power, water power), safety in the nuclear industry, nuclear waste disposal and risks from radiation. The NEIG is in favour of a balanced energy programme with nuclear energy being only a part of the overall scheme. (U.K.)

  18. Aplikace Balanced Scorecard

    OpenAIRE

    Jaroměřská, Martina

    2015-01-01

    This master's thesis deals with application of the Balanced Scorecard method to Němcova selská mlékárna Radonice, spol. s.r.o. The goal is to analyse the strategic position of the company and propose a new company strategy. Further, the strategic goals defined by the strategy are converted to a strategic map to clearly show causality relationships between the goals of the four perspectives of the Balanced Scoreboard method. The strategic goals are assigned measures and target values and initi...

  19. A balanced team generating model

    NARCIS (Netherlands)

    van de Water, Tara; van de Water, Henny; Bukman, Cock

    2007-01-01

    This paper introduces a general team balancing model. It first summarizes existing balancing methods. It is shown that for these methods it is difficult to meet all the conditions posed by Belbin on balanced teams. This mainly is caused by the complexity of the balancing problem. A mathematical mode

  20. Improved analysis of column carbon dioxide and methane data from ground-based Miniaturized Laser Heterodyne Radiometer (Mini-LHR)

    Science.gov (United States)

    Wilson, E. L.; Melroy, H.; Ramanathan, A. K.; Mao, J.; Clarke, G.; McLinden, M.; Ott, L. E.; Miller, J. H. H.; Allan, G. R.; Holben, B. N.

    2014-12-01

    We present an improved data analysis for the Mini-LHR column measurements of CO2 and CH4 that includes corrections for refraction through the atmosphere and meteorological conditions. Multi-scan averaging has also been added to compensate for current shot noise limitations and improve instrument sensitivity. Data with the improved analysis will be shown for field measurements at the TCCON site at CalTech (March 2014), Calpoly during COW-Gas (March 2014), at Mauna Loa Observatory (May 2013), and Atwater, CA (February 2013). The Mini-LHR is a miniaturized version of a laser heterodyne radiometer that implements telecommunications lasers and components to produce a significantly reduced size, low-cost instrument. Laser heterodyne radiometry has been used since the 1970s to measure atmospheric gases such as ozone, water vapor, methane, ammonia, chlorine monoxide, and nitrous oxide. The Mini-LHR is passive and uses sunlight as the primary light source to measure absorption of CO2 and CH4 in the infrared. Sunlight is collected with collimation optics mounted to the AERONET sun tracker and superimposed with laser light in a single mode fiber coupler. The signals are mixed in a fast photoreceiver (InGaAs detector), and the RF (radio frequency) beat signal is extracted. Changes in concentration of the trace gas are realized through analyzing changes in the beat frequency amplitude. In addition to the complementary aerosol optical depth measurement, tandem operation with AERONET provides a clear pathway for the mini-LHR to be expanded into a global monitoring network. AERONET has more than 450 instruments worldwide and offers coverage in key arctic regions (not covered by OCO-2) where accelerated warming due to the release of CO2 and CH4 from thawing tundra and permafrost is a concern. A mini-LHR global ground network can also provide an uninterrupted data record that will both bridge gaps in data sets and offer validation for key flight missions such as OCO-2, OCO-3, and

  1. Parkinson’s disease patients compensate for balance control asymmetry

    NARCIS (Netherlands)

    Boonstra, T.A.; Schouten, A.C.; Vugt, van J.P.P.; Bloem, B.R.; Kooij, van der H.

    2014-01-01

    In Parkinson's disease (PD) subtle balance abnormalities can already be detected in early-stage patients. One feature of impaired balance control in PD is asymmetry: one leg produces more corrective joint torque than the other. We hypothesize that in mild to moderately affected PD patients, the leas

  2. Parkinson's disease patients compensate for balance control asymmetry

    NARCIS (Netherlands)

    Boonstra, T.A.; Schouten, A.C.; Vugt, J.P.P. van; Bloem, B.R.; Kooij, H. van der

    2014-01-01

    In Parkinson's disease (PD) subtle balance abnormalities can already be detected in early-stage patients. One feature of impaired balance control in PD is asymmetry: one leg produces more corrective joint torque than the other. We hypothesize that in mild to moderately affected PD patients, the leas

  3. Toward Balance in Translation.

    Science.gov (United States)

    Costello, Nancy A.

    A study compared translations of biblical passages into different languages in Papua New Guinea. The study looked for evidence of balance between literal and free interpretation in translation style in the gospel of Mark, which is narrative and didactic material, in 12 languages, and the mainly hortatory genre in translations of 4 epistles:…

  4. National energy balance - 1977

    International Nuclear Information System (INIS)

    The national energy balance of the 1976 shows several modifications in relation to the last year. The historical serie is based in more confiable information, from several energy companies. The most greater modifications are on energy source of hard control, such as lignite and charcoal for non-siderurgic uses. (E.G.)

  5. Yin-Yang Balancing

    DEFF Research Database (Denmark)

    Li, Peter Ping

    The potential contribution of the Eastern frame of Yin-Yang Balancing lies in the mindset of "either/and", in contrast to Aristotle's either/or logic and Hegel's "both/or". Implications of this either/and thinking for science and management will be explored....

  6. National energy balance - 1978

    International Nuclear Information System (INIS)

    The national energy balance of 1978 shows some modifications in relation to the last year. New tables were included aiming to show the brazilian energy situation, such as the hydraulic potential and the non-renewable energy resources. (E.G.)

  7. National Energy Balance - 1986

    International Nuclear Information System (INIS)

    The National Energy Balance - 1986 shows energy fluxes of several primary and secondary energy sources, since the production to the final consumption in the main economic sectors, since 1970 to 1985. The incorporation of a new brazilian information is done. (E.G.)

  8. National Energy Balance - 1981

    International Nuclear Information System (INIS)

    The National Energy Balance - 1981, shows a new metodology and information in level of several economic sectors, as well as a separation of primary and secondary energy sources, its energy fluxes, i.e. production, imports, exports, consumption, etc...(E.G.)

  9. Lives in the Balance.

    Science.gov (United States)

    Our Children, 1997

    1997-01-01

    Changes in the workplace that would provide flexibility for working parents are slowly developing and receiving government, business, and societal attention. A sidebar, "Mother, Professional, Volunteer: One Woman's Balancing Act," presents an account of how one woman rearranged her professional life to enable her to do full-time parenting. (SM)

  10. Regulation of Energy Balance.

    Science.gov (United States)

    Bray, George A.

    1985-01-01

    Explains relationships between energy intake and expenditure focusing on the cellular, chemical and neural mechanisms involved in regulation of energy balance. Information is referenced specifically to conditions of obesity. (Physicians may earn continuing education credit by completing an appended test). (ML)

  11. Determination of linear displacement by envelope detection with maximum likelihood estimation

    International Nuclear Information System (INIS)

    We demonstrate in this report an envelope detection technique with maximum likelihood estimation in a least square sense for determining displacement. This technique is achieved by sampling the amplitudes of quadrature signals resulted from a heterodyne interferometer so that the resolution of displacement measurement of the order of λ/104 is experimentally verified. A phase unwrapping procedure is also described and experimentally demonstrated and indicates that the unambiguity range of displacement can be measured beyond a single wavelength.

  12. Phase-Sensitive Detection of Raman-Enhanced Nondegenerate Four-Wave Mixing by Polarization Interference

    Institute of Scientific and Technical Information of China (English)

    姜谦; 米辛; 俞祖和; 王延帮; 王利军; 傅盘铭

    2001-01-01

    We demonstrated a phase-sensitive method for studying the Raman-enhanced nondegenerate four-wave mixing (RENFWM). The reference beam is another four-wave mixing signal, which propagates along the same optical path as the RENFWM signal. This method is used for studying the phase dispersion of the third-ordersusceptibility X(3) and for the optical heterodyne detection of the RENFWM signal.

  13. Stratospheric ozone isotopes observed by air-borne and space-borne submillimeter-wave heterodyne radiometry: A sensitivity study

    Science.gov (United States)

    Kasai, Y.; Urban, J.; Takahashi, C.; Smiles Mission Team

    2003-04-01

    The variation of the isotopic composition of a species in the Earth atmosphere provides us the information on the history of the air masses, because the isotope enrichment or depletion reflects the chemical and physical processes. Since the discovery of the heavy isotope enrichment of ozone in the stratosphere in 1981 considerable progress has been made in understanding the processes that control the isotope enrichment based on atmospheric observations, laboratory experiments, and so on. However, the exact mechanism for the effect remains uncertain and accurate sequentially observations of ozone isotopomer at global scale are still very sparse. Further improvements of measurement precision can be obtained by making use of the new technological development of high-precision submillimeter-wave heterodyne radiometry based on sensitive SIS detector technology. The airborne ASUR instrument (Airborne SUb-millimeter SIS Radiometer) observed lines of asymmetric-18 ozone in the frequency region of 645 GHz with this technology since ~1994. The JEM/SMILES instrument (Japaneses Experiment Module / Superconducting sub-MIllimeter Limb Emission Sounder), to be installed on the International Space Station in 2007, will measure several ozone isotopomer in the stratosphere at global scale from space using very similar frequency bands. An error analysis including the most typical systematic errors is performed.

  14. Analysis and verification of the nonlinear error resulting from the misalignment of a polarizing beam splitter in a heterodyne interferometer

    International Nuclear Information System (INIS)

    In order to analyze and characterize the periodic nonlinear error resulting from the misalignment of a polarizing beam splitter (PBS) in a laser heterodyne interferometer more accurately, in this paper, starting from the light separating principle of thin-film PBS, we have found that the root cause of the periodic nonlinear error is the frequency mixing induced by the deviation from the Brewster angle of the incident angle or by the rotation of the incident plane when the PBS is misaligned. Moreover, we have established the direct function relationships between the periodic nonlinear error and different PBSs’ misalignment errors for the first time. The theoretical analysis shows that the periodic nonlinear error arising from the PBS’s yaw error is the largest and the maximal nonlinear errors are unequal even if the positive yaw angle is equal to the negative yaw angle. The nonlinear errors are much smaller under the PBS’s roll and pitch errors. The experiments of polarizing leakage and nonlinear error measurement under the PBS’s yaw error demonstrate that the experimental results are in agreement with the theoretical analysis. (paper)

  15. A comparison between heterodyne and homodyne interferometry to realise the SI unit of acoustic pressure in water

    Science.gov (United States)

    Koukoulas, Triantafillos; Robinson, Stephen; Rajagopal, Srinath; Zeqiri, Bajram

    2016-04-01

    Optical approaches for hydrophone calibrations offer significant advantages over existing methods based on reciprocity. In particular, heterodyne and homodyne interferometry can accurately measure particle velocity and displacements at a specific point in space thus enabling the acoustical pressure to be measured in an absolute, direct, assumption-free manner, with traceability through the SI definition of the metre. The calibration of a hydrophone can then be performed by placing the active element of the sensor at the point where the acoustic pressure field was measured and monitoring its electrical output. However, it is crucial to validate the performance and accuracy of such optical methods by direct comparison rather than through device calibration. Here we report on the direct comparison of two such optical interferometers used in underwater acoustics and ultrasonics in terms of acoustic pressure estimation and their associated uncertainties in the frequency range 200 kHz-3.5 MHz, with results showing agreement better than 1% in terms of pressure and typical expanded uncertainties better than 3% for both reported methods.

  16. High-efficiency gold-coated cross-grating for heterodyne grating interferometer with improved signal contrast and optical subdivision

    Science.gov (United States)

    Lin, Cunbao; Yan, Shuhua; Du, Zhiguang; Wei, Chunhua; Wang, Guochao

    2015-03-01

    The gold-coated cross-grating is investigated to simultaneously improve the diffraction efficiency, signal contrast and optical subdivision in heterodyne grating interferometer (HGI). Based on the theories of Fresnel-Kirchhoff diffraction integral and rigorous coupled wave analysis (RCWA), the diffractive characteristics related to diffraction efficiency, wavelength selectivity and polarization dependency are analyzed. The analysis reveals that grating pitch less than twice of the incident wavelength ought to be adopted here to avoid the second-orders, and longer wavelength is preferred to achieve high diffraction efficiency in the visible region. Meanwhile, the equivalent efficiency for TE and TM polarization, probably up to 18.32% at the wavelength of 632.8 nm, can be obtained with normal incidence which results in a signal contrast of 100% theoretically. Additionally, an eightfold optical subdivision method with cross-gratings is proposed for HGIs, and it is applicable to nearly all the existing two-dimensional (2D) optical configurations. The experimental tests on diffraction field, polarization dependency and signal contrast are performed. The results show reasonable consistency with the theoretical analysis, which validates the capability of cross-gratings for HGIs.

  17. Using balance program for energy balance analysis

    International Nuclear Information System (INIS)

    Belong with development of the economy, the energy consumption will be increased very high in the future. Vietnam has a broad range of mineral resources. There is considerable energy potential on form of coal, oil and gas, hydropower and fuel wood, Recently, Vietnam is an exporter of energy. But in next two decades, the energy sources will be enough to meet requirement? The model BALANCE was used to solve energy planning problem. The objective of this model is analyzing energy system and built an energy development strategy in long term. After using model, the results are: total coal consumption will be 17.440 Mtoe in 2020 and 32 Mtoe in 2030. the biggest coal consumer is electricity sector. Total oil production consumption will be more than 30 Mtoe in 2020 and more than 50 Mtoe in 2030. If we have 4 refinery factories from now to 2030, total oil products import will be 11 Mtoe in 2020 and 25 Mtoe in 2030. The amount of gas supply in 2030 will be 20 billions m3 (18 Mtoe). Vietnam needs to import 8.3 Mtoe more, Vietnam will become an energy importer in next 15 years. In previous years, the economy of Vietnam was mainly based on agricultural production. But Vietnam is moving rapidly from an agricultural to an industrial economy. Belong with the development of the economy, energy consumption increases very fast. So which energy sources should be used first and when it will be use...are questions need to be answered. Vietnam has a broad range of mineral resources. There is considerable energy potential on form of coal, oil and gas, hydropower and fuel wood. Recently, Vietnam is energy exporter, but in near future Vietnam has enough energy to meet demand or we need to import from outside? It should be studied carefully to answer. (author)

  18. Energy balances 2001

    International Nuclear Information System (INIS)

    Denmark's consumption of energy increased 1,6 % from 2000 to 2001, primarily due to the year 2001 being colder than the year 2000. The production of petroleum decreased from 2000 to 2001, the reason being an accident at the Gorm oil field. The production of renewable energy and natural gas, however, increased. The energy balances is an account of production, import and export, and consumption of energy. The consumption is presented for households and industry. In the energy balances the energy consumption is accounted as physical amounts as well as gross consumption. Also an account is made of the costs of energy in basis prices and in market prices, including calculation of excises on energy, CO2 and SO2. (ln)

  19. Implementation of Signal Processing in Stereo-Scopic Active Sonar Using Heterodyne System

    Directory of Open Access Journals (Sweden)

    BOKHARI Syed Umar

    2012-10-01

    Full Text Available “SONAR” is an acronym for sound ranging and navigation. It uses sound waves to detect an object in the surroundings and calculate its distance. This device has a very important applications in shipbuilding industry and military systems. Moreover it’s also being extensively used in deep sea research of new species of plants and minerals, where it is practically impossible for humans to go. The most important feature of this system is the usage of ultrasonicfrequency to detect objects that are important for data collection or detection. Transmitting an ultra sonic frequency using an electronic oscillator is not a very difficult task, the real challenge is to design a reciever that could carry out a particular modulation technique to convert an ultra-sonic frequency to an audiblefrequency. In this paper, we propose aseteroscopic active SONAR proto-type. Further, we performed a seriers of expeirments using modulation techniques. The results obtained from the experiments gives us a braod understanding of the different behaviour of asignal.

  20. France's energy balances

    International Nuclear Information System (INIS)

    Several terminological definitions of words and concepts used for the establishment of France's energy balance (i.e. the supply and utilization of energy) are presented, taken from the Energy dictionary, published in 1992 by the world Energy Council: primary, secondary, final and useful energy. Statistics concerning energy production, importation and exportation, consumption, and costs are discussed, showing the market share evolution of the different energy types; the France's energy independence ratio has increased from 22% in 1973 to 51% in 1995

  1. An ideal balance?

    OpenAIRE

    Mair, Jane

    2013-01-01

    Considers the intersection between employment policy and family law, and the changes in work and family regarding traditional gender roles. Examines UK and EU policy initiatives aimed at achieving a better work/life balance for employees with children. Argues that many of the policy aspirations are predicated on an equal opportunities employment model that may not exist in practice and also fail to reflect the realities of family life.

  2. Balance-bot

    OpenAIRE

    Abreu, Victor Vicente

    2009-01-01

    Research on inverted pendulum has gained momentum over the last decade on a number of robotic laboratories over the world; due to its unstable proprieties is a good example for control engineers to verify a control theory. To verify that the pendulum can balance we can make some simulations using a closed-loop controller method such as the linear quadratic regulator or the proportional–integral–derivative method. Also the idea of robotic teleoperation is gaining ground. Control...

  3. Ballet Balance Strategies

    OpenAIRE

    Pedersen, Camilla; Erleben, Kenny; Sporring, Jon

    2006-01-01

    Animating physically realistic human characters is challenging, since human observers are highly tuned to recognize human cues such as emotion and gender from motion patterns. The main contribution of this paper is a new model firmly based on biomechanics, which is used to animate balance and basic movements of a ballet dancers. It is supported by computer simulated experiments and it is in good agreement with biomechanical measurements of real-life dancers. Our results questions the previous...

  4. National energy balance - 1976

    International Nuclear Information System (INIS)

    Based on available data from IBGE, CNP/Petrobras, Eletrobras, Nuclebras and other governmental enterprises the National Energy Balance was done. This publication covers since 1965 to 1975. In conformity to the international rules, the energy resources used for non-energy purposes were excluded. The energy production and consumption for the next ten years were forecasted, considering the actual brazilian energy policy. (E.G.)

  5. Finance and Balanced Growth

    OpenAIRE

    Trew, Alex

    2010-01-01

    We study the relationships between various concepts of financial development and balanced economic growth. A model of endogenous growth that incorporates roles for both financial efficiency and access to financial services permits a better understanding of the relationship between the size of the financial sector (value added) and growth. Higher financial value added results from some, but not all, kinds of finance-driven growth. If greater access rather than greater efficiency generates high...

  6. In the balance

    DEFF Research Database (Denmark)

    Kluth, Michael Friederich; Pilegaard, Jess

    The present paper seeks to make sense of recent EU naval capability changes by applying neo-realist theory on the EU as an international actor in the global balance of power. The paper compares three different strands of Neo-realist theory by deducting key predictions about the expected defense...... strategy aimed at bolstering the autonomy and international influence of the Union, vis-à-vis other major powers, including the United States....

  7. Thinking About Competitive Balance

    OpenAIRE

    Allen R. Sanderson; John J. Siegfried

    2003-01-01

    Simon Rottenberg long ago noted that the nature of sports is such that competitors must be of approximately equal ability if any are to be financially successful. In recent years, sports commentators and fans, Major League Baseball itself, and even some economists have expressed growing concern about the widening disparities among team expenditures and the growing concentrations of postseason contenders and championships. In this article we compare different concepts of competitive balance, r...

  8. Simple Cell Balance Circuit

    Science.gov (United States)

    Johnson, Steven D.; Byers, Jerry W.; Martin, James A.

    2012-01-01

    A method has been developed for continuous cell voltage balancing for rechargeable batteries (e.g. lithium ion batteries). A resistor divider chain is provided that generates a set of voltages representing the ideal cell voltage (the voltage of each cell should be as if the cells were perfectly balanced). An operational amplifier circuit with an added current buffer stage generates the ideal voltage with a very high degree of accuracy, using the concept of negative feedback. The ideal voltages are each connected to the corresponding cell through a current- limiting resistance. Over time, having the cell connected to the ideal voltage provides a balancing current that moves the cell voltage very close to that ideal level. In effect, it adjusts the current of each cell during charging, discharging, and standby periods to force the cell voltages to be equal to the ideal voltages generated by the resistor divider. The device also includes solid-state switches that disconnect the circuit from the battery so that it will not discharge the battery during storage. This solution requires relatively few parts and is, therefore, of lower cost and of increased reliability due to the fewer failure modes. Additionally, this design uses very little power. A preliminary model predicts a power usage of 0.18 W for an 8-cell battery. This approach is applicable to a wide range of battery capacities and voltages.

  9. Gait and balance disorders.

    Science.gov (United States)

    Masdeu, Joseph C

    2016-01-01

    This chapter focuses on one of the most common types of neurologic disorders: altered walking. Walking impairment often reflects disease of the neurologic structures mediating gait, balance or, most often, both. These structures are distributed along the neuraxis. For this reason, this chapter is introduced by a brief description of the neurobiologic underpinning of walking, stressing information that is critical for imaging, namely, the anatomic representation of gait and balance mechanisms. This background is essential not only in order to direct the relevant imaging tools to the regions more likely to be affected but also to interpret correctly imaging findings that may not be related to the walking deficit object of clinical study. The chapter closes with a discussion on how to image some of the most frequent etiologies causing gait or balance impairment. However, it focuses on syndromes not already discussed in other chapters of this volume, such as Parkinson's disease and other movement disorders, already discussed in Chapter 48, or cerebellar ataxia, in Chapter 23, in the previous volume. As regards vascular disease, the spastic hemiplegia most characteristic of brain disease needs little discussion, while the less well-understood effects of microvascular disease are extensively reviewed here, together with the imaging approach. PMID:27430451

  10. Stabilized hot electron bolometer heterodyne receiver at 2.5 THz

    OpenAIRE

    Hayton, D.J.; Gao, J. R.; Kooi, J. W.; Ren, Y; Zhang, W; de Lange, G.

    2012-01-01

    We report on a method to stabilize a hot electron bolometer (HEB) mixer at 2.5 THz. The technique utilizes feedback control of the local oscillator (LO) laser power by means of a swing-arm actuator placed in the optical beam path. We demonstrate that this technique yields a factor of 50 improvement in the spectroscopic Allan variance time which is shown to be over 30 s in a 12 MHz noise fluctuation bandwidth. Furthermore, broadband signal direct detection effects may be minimized by this tech...

  11. Balanced skills among nascent entrepreneurs

    OpenAIRE

    Stuetzer, Michael; Obschonka, Martin; Schmitt-Rodermund, Eva

    2012-01-01

    This paper examines the effects and origins of balanced skills among nascent entrepreneurs. In a first step we apply Lazear’s jack-of-all-trades theory to investigate performance effects of a balanced skill set. Second, we investigate potential sources of balanced skills, thereby testing the investment hypothesis against the endowment hypothesis. Analyzing data on high-potential nascent projects, we find support for the notion that balanced skills are important for making progress in the vent...

  12. Temperature Measurements in Venus Upper Atmosphere between 2007 and 2015 from ground-based Infrared Heterodyne Spectroscopy

    Science.gov (United States)

    Krause, Pia; Wischnewski, Carolin; Sornig, Manuela; Stangier, Tobias; Sonnabend, Guido; Herrmann, Maren; Wiegand, Moritz; Kostiuk, Theodor; Livengood, Timothy

    2016-04-01

    The structure of Venus atmosphere has been the target of intense studies in the past decade. Among manifold ground based observations, the recent space mission Venus Express in particular has shed light on many open questions concerning the thermal and the dynamical behavior of its atmosphere. A comprehensive understanding of this atmospheric region is still missing. Therefore, direct measurements of atmospheric parameters on various time scales and at different locations on the planet are essential for an understanding and for the validation of global circulation models. Such observations are provided by the infrared heterodyne spectrometers THIS (University of Cologne), HIPWAC (NASA GSFC) and MILAHI (Tohoku University). These instruments fully resolve CO2 non-LTE emission lines for Doppler-wind and temperature retrievals at an pressure level of 1μbar (~110 km) by operating around 10μm. The Long- and short-term variability of daytime temperatures at the ~1μbar level from ground-based observing campaigns between 2007 to 2015 shall be presented. The observations yield a large quantity of temperature measurements at different positions on the planetary disk which allows to map a good part of the dayside of Venus. In addition a detailed study of the interesting but not well understood and only poorly investigated area close to the terminator will be given. Investigations on the general behavior of the temperature and differences between the morning and evening terminators are accomplished. Ongoing analysis of thermal variability and comparison to other observing methods and model calculations are in progress and will be included in the presentation if already available.

  13. The evaluation of phasemeter prototype performance for the space gravitational waves detection.

    Science.gov (United States)

    Liu, He-Shan; Dong, Yu-Hui; Li, Yu-Qiong; Luo, Zi-Ren; Jin, Gang

    2014-02-01

    Heterodyne laser interferometry is considered as the most promising readout scheme for future space gravitational wave detection missions, in which the gravitational wave signals disguise as small phase variances within the heterodyne beat note. This makes the phasemeter, which extracts the phase information from the beat note, the key device to this system. In this paper, a prototype of phasemeter based on digital phase-locked loop technology is developed, and the major noise sources which may contribute to the noise spectra density are analyzed in detail. Two experiments are also carried out to evaluate the performance of the phasemeter prototype. The results show that the sensitivity is achieved 2π μrad/√Hz in the frequency range of 0.04 Hz-10 Hz. Due to the effect of thermal drift, the noise obviously increases with the frequencies down to 0.1 mHz. PMID:24593376

  14. Lesson "Balance in Nature

    Science.gov (United States)

    Chapanova, V.

    2012-04-01

    Lesson "Balance in Nature" This simulation game-lesson (Balance in Nature) gives an opportunity for the students to show creativity, work independently, and to create models and ideas. It creates future-oriented thought connected to their experience, allowing them to propose solutions for global problems and personal responsibility for their activities. The class is divided in two teams. Each team chooses questions. 1. Question: Pollution in the environment. 2. Question: Care for nature and climate. The teams work on the chosen tasks. They make drafts, notes and formulate their solutions on small pieces of paper, explaining the impact on nature and society. They express their points of view using many different opinions. This generates alternative thoughts and results in creative solutions. With the new knowledge and positive behaviour defined, everybody realizes that they can do something positive towards nature and climate problems and the importance of individuals for solving global problems is evident. Our main goal is to recover the ecological balance, and everybody explains his or her own well-grounded opinions. In this work process the students obtain knowledge, skills and more responsible behaviour. This process, based on his or her own experience, dialogue and teamwork, helps the participant's self-development. Making the model "human↔ nature" expresses how human activities impact the natural Earth and how these impacts in turn affect society. Taking personal responsibility, we can reduce global warming and help the Earth. By helping nature we help ourselves. Teacher: Veselina Boycheva-Chapanova " Saint Patriarch Evtimii" Scholl Str. "Ivan Vazov"-19 Plovdiv Bulgaria

  15. Balancing innovation and evidence.

    Science.gov (United States)

    Pilcher, Jobeth W

    2015-01-01

    Nurse educators are encouraged to use evidence to guide their teaching strategies. However, evidence is not always available. How can educators make decisions regarding strategies when data are limited or absent? Where do innovation and creativity fit? How can innovation be balanced with evidence? This article provides a discussion regarding other sources of evidence, such as extrapolations, theories and principles, and collective expertise. Readers are encouraged to review the options and then analyze how they might be applied to innovation in education. PMID:25790361

  16. Watt and joule balances

    Science.gov (United States)

    Robinson, Ian A.

    2014-04-01

    The time is fast approaching when the SI unit of mass will cease to be based on a single material artefact and will instead be based upon the defined value of a fundamental constant—the Planck constant—h . This change requires that techniques exist both to determine the appropriate value to be assigned to the constant, and to measure mass in terms of the redefined unit. It is important to ensure that these techniques are accurate and reliable to allow full advantage to be taken of the stability and universality provided by the new definition and to guarantee the continuity of the world's mass measurements, which can affect the measurement of many other quantities such as energy and force. Up to now, efforts to provide the basis for such a redefinition of the kilogram were mainly concerned with resolving the discrepancies between individual implementations of the two principal techniques: the x-ray crystal density (XRCD) method [1] and the watt and joule balance methods which are the subject of this special issue. The first three papers report results from the NRC and NIST watt balance groups and the NIM joule balance group. The result from the NRC (formerly the NPL Mk II) watt balance is the first to be reported with a relative standard uncertainty below 2 × 10-8 and the NIST result has a relative standard uncertainty below 5 × 10-8. Both results are shown in figure 1 along with some previous results; the result from the NIM group is not shown on the plot but has a relative uncertainty of 8.9 × 10-6 and is consistent with all the results shown. The Consultative Committee for Mass and Related Quantities (CCM) in its meeting in 2013 produced a resolution [2] which set out the requirements for the number, type and quality of results intended to support the redefinition of the kilogram and required that there should be agreement between them. These results from NRC, NIST and the IAC may be considered to meet these requirements and are likely to be widely debated

  17. Die Balance der Verantwortung

    OpenAIRE

    Abt, Andreas

    2006-01-01

    Die Balance der Verantwortung Ein Modell der Pädagogik zur Entwicklung von Verantwortungsfähigkeit Diese Arbeit befasst sich mit dem Begriff der Verantwortung, der in der Gesellschaft häufig verwendet wird und dort in der Regel positiv belegt ist. Neben der Vorstellung einer modernen Begriffsinterpretation lege ich die Bedeutung des Themas Verantwortung für die menschliche Existenz und damit auch für die Themen Erziehung und Bildung dar. Ausgehend von der Frage, warum Menschen in der d...

  18. Analysis of phase noise and cnr degradation of externally generated lo signal in lnb for ku-band dvb-s systems by heterodyning two lasers

    OpenAIRE

    Khan, M R H; Burla, M.; Roeloffzen, C. G. H.; Marpaung, D.A.I.; Etten, van, W.

    2009-01-01

    We investigate the externally generation of an LO signal by optical heterodyning, which is then distributed to each of the mixers at every antenna element of a phased array antenna used for standard DVB-S (digital Video Broadcasting-Satellite) reception system. The system1 is presented in Figure 1. The Ku-Band (10.7 GHz ~12.75 GHz) RF signal from the antenna array is amplified and then down converted to IF (950 MHz to 2150 MHz) at the mixer by a 9.75 GHz LO signal generated by optical heterod...

  19. Detailed calculation of spectral noise caused by measurement errors of Mach-Zehnder interferometer optical path phases in a spatial heterodyne spectrometer with a phase shift scheme.

    Science.gov (United States)

    Takada, Kazumasa; Seino, Mitsuyoshi; Chiba, Akito; Okamoto, Katsunari

    2013-04-20

    We calculate the root mean square (rms) value of the spectral noise caused by optical path phase measurement errors in a spatial heterodyne spectrometer (SHS) featuring a complex Fourier transformation. In our calculation the deviated phases of each Mach-Zehnder interferometer in the in-phase and quadrature states are treated as statistically independent random variables. We show that the rms value is proportional to the rms error of the phase measurement and that the proportionality coefficient is given analytically. The relationship enables us to estimate the potential performance of the SHS such as the sidelobe suppression ratio for a given measurement error. PMID:23669661

  20. Balance of multi-wavelets

    Institute of Scientific and Technical Information of China (English)

    MAO Yibo

    2003-01-01

    The discrete scalar data need prefiltering when transformed by discrete multi-wavelet, but prefiltering will make some properties of multi-wavelets lost. Balanced multi-wavelets can avoid prefiltering. The sufficient and necessary condition of p-order balance for multi-wavelets in time domain, the interrelation between balance order and approximation order and the sampling property of balanced multi-wavelets are investigated. The algorithms of 1-0rder and 2-0rder balancing for multi-wavelets are obtained. The two algorithms both preserve the orthogonal relation between multi-scaling function and multi-wavelets. More importantly, balancing operation doesn't increase the length of filters, which suggests that a relatively short balanced multiwavelet can be constructed from an existing unbalanced multi-wavelet as short as possible.

  1. Negative leave balances

    CERN Multimedia

    Human Resources Department

    2005-01-01

    Members of the personnel entitled to annual leave and, where appropriate, saved leave and/or compensatory leave are requested to take note of the new arrangements described below, which were recommended by the Standing Concertation Committee (SCC) at its meeting on 1Â September 2005 and subsequently approved by the Director-General. The changes do not apply to members of the personnel participating in the Progressive Retirement Programme (PRP) or the Part-time Work as a pre-retirement measure, for whom the specific provisions communicated at the time of joining will continue to apply. Â Negative balances in annual leave, saved leave and/or compensatory leave accounts at the end of the leave year (30th September) and on the date on which bonuses are credited to the saved leave account (31st December): Where members of the personnel have a leave account with a negative balance on 30Â September and/or 31Â December, leave will automatically be transferred from one account to another on the relevant dates i...

  2. Negative leave balances

    CERN Multimedia

    Human Resources Department

    2005-01-01

    Members of the personnel entitled to annual leave and, where appropriate, saved leave and/or compensatory leave are requested to take note of the new arrangements described below, which were recommended by the Standing Concertation Committee (SCC) at its meeting on 1 September 2005 and subsequently approved by the Director-General. The changes do not apply to members of the personnel participating in the Progressive Retirement Programme (PRP) or the Part-time Work as a pre-retirement measure, for whom the specific provisions communicated at the time of joining will continue to apply.  Negative balances in annual leave, saved leave and/or compensatory leave accounts at the end of the leave year (30th September) and on the date on which bonuses are credited to the saved leave account (31st December): Where members of the personnel have a leave account with a negative balance on 30 September and/or 31 December, leave will automatically be transferred from one account to another on the relevant dates in or...

  3. Development of he Nanosat Oxygen A-Band Spatial Heterodyne Interferometer (NOASHIN)

    Science.gov (United States)

    Watchorn, S. R.; Noto, J.; Doe, R. A.; Fish, C. S.

    2014-12-01

    The abundance of CO2 in the mesopause region has long been shown to track with mesopause cooling, making mesopause-region temperature measurement a way to track CO2 abundance in this critical region, where climate change indications often manifest early. One of the brightest thermally excited emissions in the mesopause region is the O2 A-band, whose emission peaks are significantly modulated as a function of temperature. Thus, spectroscopic recovery of a set of A-band emission lines between 763 and 765 nm, and a comparison of peak intensities, will provide information about mesopause temperature, and thus CO2 abundance. To get global coverage of this emission with high time resolution ( footprint of 9-km along-track. The current development project will integrate a prototype NOASHIN SHS monolith into a 1.5-U CubeSat engineering prototype at the design SWAP requirements. The prototype will be detect emissions of the expected intensity (~700 R) from a lab source near the A-band and offload data onto a local computer for analysis.

  4. Development of The Liquid Refractometer Using Optical Fiber Detection

    Institute of Scientific and Technical Information of China (English)

    Ming-Horng; Chiu; Hsiharng; Yang; Shao-Nan; Hsu

    2003-01-01

    This article presents a new technique of optical heterodyne interferometry to measure the refractive index of some unknown liquid. It's based on total -internal-reflection heterodyne interferometry and the uses of fiber sensor technology.

  5. Development of The Liquid Refractometer Using Optical Fiber Detection

    Institute of Scientific and Technical Information of China (English)

    Ming-Horng Chiu; Hsiharng Yang; Shao-Nan Hsu

    2003-01-01

    This article presents a new technique of optical heterodyne interferometry to measure the refractive index of some unknown liquid. It's based on total-internal-reflection heterodyne interferometry and the uses of fiber sensor technology.

  6. Stratospheric ozone isotope enrichment studied by submillimeter-wave heterodyne radiometry

    Science.gov (United States)

    Kasai, Y.; Urban, J.; Takahashi, K.; JEM/SMILES Science-Team,

    2002-05-01

    Since the discovery of the heavy isotope enrichment of ozone formation in the stratosphere in 1981, considerable progress has been made in understanding the processes that control the isotope enrichment by using mass spectrometry, spectrometric techniques, laboratory measurements, and so on. The detection limit of the mass spectrometers is enough to discuss these isotope enrichments, but symmetric and asymmetric ozone isotopes cannot be distinguished. It is important to observe symmetric and asymmetric ozone isotopes separately with enough accuracy to understand the mechanism of the ozone isotope enrichment for the ozone formation chemistry. Measurements of the ozone isotopes using a new technology of he superconducting submillimeter-wave limb emission spectrometer (SMILES) have been proposed. The instrument is planned to be aboard the Japanese Experiment Module (JEM) at the International Space Station. The SMILES instrument is planned to be launched in 2006. The SMILES instrument measures thermal emissions from ozone isotopes as well as ozone-depletion-related molecules such as ClO, HCl, HO2, HNO3 and BrO in the frequency bands at 624.32-626.32 GHz and 649.12-650.32 GHz. Overview of this experiment, such as new techniques for a high-sensitive sounding, measurement coverage, measurement frequency, is described. The scientific objective of the SMILES experiment, including a brief review on the controversial problem of stratospheric ozone isotope anomaly, is presented. The error analysis of the SMILES measurement is evaluated by using the SMILES simulator for all 5 isotopes of normal ozone, asymmetric-17-ozone, asymmetric-18-ozone, symmetric-17-ozone, symmetric-18-ozone. The evaluation suggests that the global distributions of symmetric-17-ozone, asymmetric-18-ozone, symmetric-17-ozone, as well as normal ozone can be obtained from the single profile, with the errors of less than about 1 % between 20 and 40 km with the partial column about 5 km.

  7. Kin Selection - Mutation Balance

    DEFF Research Database (Denmark)

    Dyken, J. David Van; Linksvayer, Timothy Arnold; Wade, Michael J.

    2011-01-01

    Abstract Social conflict, in the form of intraspecific selfish "cheating" has been observed in a number of natural systems. However, a formal, evolutionary genetic theory of social cheating that provides an explanatory, predictive framework for these observations is lacking. Here we derive the kin...... selection-mutation balance, which provides an evolutionary null hypothesis for the statics and dynamics of cheating. When social interactions have linear fitness effects and Hamilton´s rule is satisfied, selection is never strong enough to eliminate recurrent cheater mutants from a population, but cheater...... lineages are transient and do not invade. Instead, cheating lineages are eliminated by kin selection but are constantly reintroduced by mutation, maintaining a stable equilibrium frequency of cheaters. The presence of cheaters at equilibrium creates a "cheater load" that selects for mechanisms of cheater...

  8. Energy balance climate models

    Science.gov (United States)

    North, G. R.; Cahalan, R. F.; Coakley, J. A., Jr.

    1981-01-01

    An introductory survey of the global energy balance climate models is presented with an emphasis on analytical results. A sequence of increasingly complicated models involving ice cap and radiative feedback processes are solved, and the solutions and parameter sensitivities are studied. The model parameterizations are examined critically in light of many current uncertainties. A simple seasonal model is used to study the effects of changes in orbital elements on the temperature field. A linear stability theorem and a complete nonlinear stability analysis for the models are developed. Analytical solutions are also obtained for the linearized models driven by stochastic forcing elements. In this context the relation between natural fluctuation statistics and climate sensitivity is stressed.

  9. A Balancing Act?

    DEFF Research Database (Denmark)

    Gerstlberger, Wolfgang; Knudsen, Mette Præst; Stampe, Ian

    efficiency moderates the effect of market attention on new product development. The paper therefore concludes that product innovation and energy efficiency is a balancing act, focusing on one will have detrimental effects on the other! These findings point to the conclusion that researchers and practitioners......With an undifferentiated catchword ‘eco-innovation’ is a largely understudied area, but of high relevance to the society and companies given the strong focus especially by governments on grand challenges like climate change, green technologies and environmental challenges. The paper utilizes the...... 2009 European Manufacturing Survey for the Danish sub-sample including 335 manufacturing firms. Through factor analysis, the paper confirms three main focus areas of new product development in relation to production facilities: efficiency considerations, market attention and greening of innovation...

  10. The balanced mind

    DEFF Research Database (Denmark)

    Allen, Micah; Smallwood, Jonathan; Christensen, Joanna;

    2013-01-01

    Self-generated thoughts unrelated to ongoing activities, also known as "mind-wandering," make up a substantial portion of our daily lives. Reports of such task-unrelated thoughts (TUTs) predict both poor performance on demanding cognitive tasks and blood-oxygen-level-dependent (BOLD) activity in......-wandering on response inhibition and monitoring, using the Error Awareness Task (EAT). We expected to replicate links between TUT and reduced inhibition, and explored whether variance in TUT would predict improved error monitoring, reflecting a capacity to balance between internal and external cognition. By...... during error awareness, supporting a link between monitoring and TUTs. Altogether our results suggest that although TUT is detrimental to task performance, fluctuations in attention between self-generated and external task-related thought is a characteristic of individuals with greater metacognitive...

  11. Balancing Trust and Control

    DEFF Research Database (Denmark)

    Jagd, Søren

    2010-01-01

    The purpose of this paper is to show that conceptualizing trust and control as interactively related processes, as opposed to more static conceptualizations of the two concepts and the relations between them, adds importantly towards understanding the challenges involved in balancing of trust and...... control in organizations. The paper examines recent literature on the conceptualization of the relation between trust and control in and between organizations. The literature review shows that trust and control has been conceptualized as either substituting or complementing each other. Further, it is...... found that the complementary/substitution debate calls for an explicit conceptualization of the relation between trust and control as an interactive process, in contrast to earlier conceptualizations of trust and control as two relatively static and isolated concepts. While the static perspective on...

  12. Gravity in the balance

    International Nuclear Information System (INIS)

    Although Einstein's theories of relativity showed that Newton's ideas about gravity, space and time were approximations, general relativity still predicts that the gravitational force between two point objects will obey an inverse-square law in the limit of low velocities and weak gravitational fields. Of course, we know that general relativity is probably an approximation as well and that some grander theory - possibly involving extra dimensions of space - will unify gravity with the other fundamental forces. Many of these theories predict that the inverse-square law will break down at distances that are becoming accessible to (relatively small) experiments with torsion balances. As researchers from the Eoet-Wash group in Seattle report 'Testing the gravitational inverse-square law', the inverse-square law has survived all tests so far, but its days are surely numbered. (U.K.)

  13. A Balancing Act?

    DEFF Research Database (Denmark)

    Gerstlberger, Wolfgang; Stampe, Ian; Knudsen, Mette Præst

    efficiency moderates the effect of market attention on new product development. The paper therefore concludes that product innovation and energy efficiency is a balancing act, focusing on one will have detrimental effects on the other! These findings point to the conclusion that researchers and practitioners....... Logistic regression analysis demonstrates that while market attention is important for new product development, green aspects of innovation and efficiency considerations for innovation are important for the energy efficiency of the production companies. Combining these models highlights that energy...... in innovation management have to take the specificities and interactions of different types of eco-innovation more carefully in consideration than so far and to formulate new managerial practices combining energy efficiency and product innovation....

  14. Direct multi-channel optical spectrum analysis of radio-wave signals using collinear wave heterodyning in the single acousto-optical cell

    International Nuclear Information System (INIS)

    An attempt is made to improve the accuracy of a multi-channel parallel acousto-optical spectrum analysis through involving an additional nonlinear conversion into data processing. For this purpose we investigate the potential of exploiting a co-directional collinear wave heterodyning within an analysis of ultra-high-frequency radio-wave signals. The wave heterodyning under the proposal is performed via mixing the longitudinal elastic waves of finite amplitudes. It leads to a two-cascade processing in the single-crystalline cell and makes it possible to improve the relative frequency resolution of the acousto-optical spectrum analysis by an order of magnitude at the same frequency range. Both the theoretical findings and the corresponding estimations were used in proof-of-principle experiments directed at creating a new type of acousto-optical cell. The general concept of the proposed method and the basic conclusions are confirmed by experiments with the developed acousto-optic cell made of a lead molybdate crystal

  15. Measurement of 13CO2/12CO2 abundance by nondispersive infrared heterodyne ratiometry as an alternative to gas isotope ratio mass spectrometry

    International Nuclear Information System (INIS)

    The authors report the performance of a prototype nondispersive infrared heterodyne ratiometer in the analysis of seven reference gas samples containing 3.0% CO2 in air, and isotopic enrichments from -85 to +329 δ per thousand vs. PDB as measured by gas isotope ratio mass spectrometry. The instrument response in volts-1 (V-1) varied from -0.51 to 1.22 over the range of -85 to +329 per thousand. A mean instrument response with a 0.0015 standard deviation (0.375 per thousand) required 110 s of signal averaging at a 1-s sampling rate. The calibration curve of instrument response vs. δ per thousand was linear over the entire range and had a slope of 0.003 89 +/- 0.000 03 (SD), an intercept of -0.168 +/- 0.005, and a standard error of 0.009. With this curve, 45 s of data acquisition at a mean instrument response of -0.280 V-1 attained a standard deviation of +/- 1.3 per thousand at -28.7 per thousand. Nondispersive infrared heterodyne ratiometry can analyze the 13C content of respiratory gas samples with acceptable accuracy and sensitivity for clinical studies

  16. A compact ground-based laser heterodyne radiometer for global column measurements of CO2 and CH4

    Science.gov (United States)

    Steel, Emily; Clarke, Gregory; Ramanathan, Anand; Mao, Jianping; Ott, Lesley; Duncan, Bryan; Melroy, Hilary; McLinden, Matthew; Holben, Brent; Houston Miller, J.

    2015-04-01

    Implementing effective global strategies to understand climate change is hindered by a lack of understanding of both anthropogenic emissions and land and ocean carbon reservoirs. Though in situ surface measurements and satellites provide valuable information for estimating carbon fluxes, areas not well covered by current observing systems (e.g. high latitude regions, tropical forests and wetlands) remain poorly understood. Deficiencies in understanding the processes governing carbon flux introduce considerable uncertainty to predictions of climate change over the coming century. Our vision is to enhance worldwide carbon monitoring by developing a low-cost ground network of miniaturized laser heterodyne radiometer (Mini-LHR) instruments that measure CO2 and CH4 in the atmospheric column. Ground-based remote sensing has the potential to fill gaps in the satellite data record while providing a complementary long-term observational record. This uninterrupted data record, would both bridge gaps in data sets and offer validation for key flight missions such as OCO-2, OCO-3 and ASCENDS. Mini-LHR instruments will be deployed as an accompaniment to AERONET. In addition to the complementary aerosol optical depth measurement, tandem operation with AERONET provides a clear pathway for the Mini-LHR to be expanded into a global monitoring network. AERONET has more than 500 instruments worldwide offering coverage in key arctic regions (not covered by OCO-2) where accelerated warming due to the release of CO2 and CH4 from thawing tundra and permafrost is a concern. Mini-LHR instruments at AERONET locations could also greatly improve data coverage in regions with large flux uncertainties such as North America and Western Europe, and under-sampled areas such as South America and Asia. Currently, the only ground global network that routinely measures multiple greenhouse gases in the atmospheric column is TCCON with 18 operational sites worldwide and two in the US. Cost and size of

  17. Aposematism: balancing salience and camouflage.

    Science.gov (United States)

    Barnett, James B; Scott-Samuel, Nicholas E; Cuthill, Innes C

    2016-08-01

    Aposematic signals are often characterized by high conspicuousness. Larger and brighter signals reinforce avoidance learning, distinguish defended from palatable prey and are more easily memorized by predators. Conspicuous signalling, however, has costs: encounter rates with naive, specialized or nutritionally stressed predators are likely to increase. It has been suggested that intermediate levels of aposematic conspicuousness can evolve to balance deterrence and detectability, especially for moderately defended species. The effectiveness of such signals, however, has not yet been experimentally tested under field conditions. We used dough caterpillar-like baits to test whether reduced levels of aposematic conspicuousness can have survival benefits when predated by wild birds in natural conditions. Our results suggest that, when controlling for the number and intensity of internal contrast boundaries (stripes), a reduced-conspicuousness aposematic pattern can have a survival advantage over more conspicuous signals, as well as cryptic colours. Furthermore, we find a survival benefit from the addition of internal contrast for both high and low levels of conspicuousness. This adds ecological validity to evolutionary models of aposematic saliency and the evolution of honest signalling. PMID:27484645

  18. Variance approximation under balanced sampling

    OpenAIRE

    Deville, Jean-Claude; Tillé, Yves

    2016-01-01

    A balanced sampling design has the interesting property that Horvitz–Thompson estimators of totals for a set of balancing variables are equal to the totals we want to estimate, therefore the variance of Horvitz–Thompson estimators of variables of interest are reduced in function of their correlations with the balancing variables. Since it is hard to derive an analytic expression for the joint inclusion probabilities, we derive a general approximation of variance based on a residual technique....

  19. Designing Multinational Electricity Balancing Markets

    OpenAIRE

    Van der Veen, R.A.C.

    2012-01-01

    In today’s unbundled electricity markets, the balancing market is an intricate institutional arrangement that makes sure that the balance between electricity supply and demand is maintained. In the light of the development of a single electricity market in Europe, harmonization and integration of currently national balancing markets have received an increasing attention from governments, system operators, and regulators. This dissertation provides a systematic overview of the possibilities an...

  20. Psychology of the nuclear balance

    Energy Technology Data Exchange (ETDEWEB)

    Sonntag, P.

    1981-10-01

    The balance of military forces is meant to prevent war. But it is a very precarious balance, which becomes all the more dubious when the deterrent is no longer psychologically effective: when the country attacked is deterred from striking back with nuclear weapons. A unilateral disarmament above the overkill level would be possible without endangering the balance. It would improve the climate for mutual disarmament.

  1. Radar channel balancing with commutation

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-02-01

    When multiple channels are employed in a pulse-Doppler radar, achieving and maintaining balance between the channels is problematic. In some circumstances the channels may be commutated to achieve adequate balance. Commutation is the switching, trading, toggling, or multiplexing of the channels between signal paths. Commutation allows modulating the imbalance energy away from the balanced energy in Doppler, where it can be mitigated with filtering.

  2. Detecting single viruses and nanoparticles using whispering gallery microlasers

    CERN Document Server

    He, Lina; Zhu, Jiangang; Kim, Woosung; Yang, Lan

    2011-01-01

    Detection and characterization of individual nano-scale particles, virions, and pathogens are of paramount importance to human health, homeland security, diagnostic and environmental monitoring[1]. There is a strong demand for high-resolution, portable, and cost-effective systems to make label-free detection and measurement of individual nanoparticles, molecules, and viruses [2-6]. Here, we report an easily accessible, real-time and label-free detection method with single nanoparticle resolution that surpasses detection limit of existing micro- and nano-photonic devices. This is achieved by using an ultra-narrow linewidth whispering gallery microlaser, whose lasing line undergoes frequency splitting upon the binding of individual nano-objects. We demonstrate detection of polystyrene and gold nanoparticles as small as 15 nm and 10 nm in radius, respectively, and Influenza A virions by monitoring changes in self-heterodyning beat note of the split lasing modes. Experiments are performed in both air and aqueous ...

  3. Paul Collier : Balancing beams

    CERN Multimedia

    2009-01-01

    As former head of AB Operations, Paul Collier and his group were in the ‘cockpit’ for the LHC’s maiden voyage - piloting the first beam around the ring. But now, as Head of the Beams Department, he will need his feet firmly on the ground in order to balance all the beam activities at CERN. "As Department Head, I’ll have less direct contact with the machines," Collier says with a hint of regret. "I’ll still obviously be very involved, but they won’t actually let me loose in front of the keyboard anymore!" As the new Head of the BE Department, Collier will be in charge of nearly 400 people, and will oversee all the beam activities, including the preparations for the longest period of beam operation in the history of CERN. In the new organization, the BE, TE and EN Departments have been grouped together in the Accelerator and Technology Sector. "‘Partnership’ is a key word for the three departments," says Collier. "The n...

  4. Interim balance: Ecology

    International Nuclear Information System (INIS)

    Subjects: The ecology problem - world wide. Sectoral balances: The examples of energy, transportation, chemistry, agriculture and food industry, water supply. Destruction of nature and human discord. Conservatives in our political parties and their views on environmental protection. Alliance between reds and 'greens', integration between reds and greens. The Rhine initiative. Lead respects no borders, experiences of citizens' action groups in Lothringia and the Saar district. International airport Munich-II/comments by a protestant. 'Give priority to life'/A hearing on environmental protection. 4:96 - 'greens' in the Bremen Senate. Policy in a hard-hearing world/psychology of citizens' action groups. Critical ecological research and scientific establishment. Full productivity and ecology. The deluge to follow/Hints on how to build an ark. Symbiosis is more than coexistence/Ecologists' social theory. Throwing in two hundred elementary particles/on the way to an ecological concept of science. Scientific journals. Alternative literature. Teaching model for a teaching subject 'ecology'. (orig.)

  5. Balancing safety and economics

    International Nuclear Information System (INIS)

    The safety requirements of NPPs have always aimed at limiting societal risks. This risk approach initially resulted in deterministic design criteria and concepts. In the 1980s the paradigm 'safety at all costs' arose and often led to questionable backfitting measures. Conflicts between new requirements, classical design concepts and operational demands were often ignored. The design requirements for advanced reactors ensure enhanced protection against severe accidents. Still, it is questionable whether the 'no-damage-outside-the-fence' criteria can be achieved deterministically and at competitive costs. Market deregulation and utility privatisation call for a balance between safety and costs, without jeopardising basic safety concepts. An ideal approach must be risk-based and imply modern PSAs and new methods for cost-benefit and ALARA analyses, embed nuclear risks in a wider risk spectrum, but also make benefits transparent within the context of a broader life experience. Governments should define basic requirements, minimum standards and consistent comparison criteria, and strengthen operator responsibility. Internationally sufficient and binding safety requirements must be established and nuclear technology transfer handled in a responsible way, while existing plants, with their continuous backfitting investments, should receive particular attention. (orig.)

  6. Par Pond water balance

    International Nuclear Information System (INIS)

    A water budget for the Par Pond hydrologic system was established in order to estimate the rate of groundwater influx to Par Pond. This estimate will be used in modeling exercises to predict Par Pond reservoir elevation and spillway discharge in the scenario where Savannah River water is no longer pumped and discharged into Par Pond. The principal of conservation of mass was used to develop the water budget, where water inflow was set equal to water outflow. Components of the water budget were identified, and the flux associated with each was determined. The water budget was considered balanced when inflow and outflow summed to zero. The results of this study suggest that Par Pond gains water from the groundwater system in the upper reaches of the reservoir, but looses water to the groundwater system near the dam. The rate of flux of groundwater from the water table aquifer into Par Pond was determined to be 13 cfs. The rate of flux from Par Pond to the water table aquifer near the dam was determined to be 7 cfs

  7. Balancing "we" and "me".

    Science.gov (United States)

    Congdon, Christine; Flynn, Donna; Redman, Melanie

    2014-10-01

    The open office is the dominant form of workspace design for good reason: It fosters collaboration, promotes learning, and nurtures strong culture. But what most companies fail to realize is that collaboration has a natural rhythm that requires both interaction and private contemplation. Companies have been trying for decades to find the balance between public and private workspace that best supports collaboration. In 1980 52% of U.S. employees lacked workspaces where they could concentrate without distraction. In response, high-walled cubicles took over the corporate landscape. By the late 1990s, the tide had turned, and only 23% of employees wanted more privacy, and 50% wanted more access to other people. Ever since, firms have been beefing up spaces that support collaboration and shrinking areas for individual work. But the pendulum seems to have swung too far: Once again, people feel a pressing need for privacy, not only to do heads-down work but to cope with the intensity of work today. To address these needs, according to the authors, we have to rethink our assumptions about privacy. Traditionally defined in physical terms, privacy is now about the individual's ability to control information and stimulation. In this article, the authors examine workspace design through the new lens of privacy and offer insights on how to foster teamwork and solitude. PMID:25509575

  8. The right balance

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    Over the course of her career as a physicist, Felicitas Pauss, currently responsible for CERN's External Relations, has often been the sole woman in an environment dominated by men. While she freely admits that being a woman physicist can have as many advantages as disadvantages, she thinks the best strategy is to maintain the right balance.   From a very early age, Felicitas Pauss always wanted to be involved in projects that interested and fascinated her. That's how she came to study physics. When she was a first-year university student in Austria in 1970, it was still fairly uncommon for women to go into physics research. "I grew up in Salzburg with a background in music. At that time, it was certainly considered more ‘normal’ for a woman to study music than to do research in physics. But already in high school I was interested in physics and technical instruments and wanted to know how things work and what they are made of”. At the beginning of her care...

  9. Optimal allocation in balanced sampling

    OpenAIRE

    Tillé, Yves; Favre, Anne-Catherine

    2016-01-01

    The development of new sampling methods allows the selection of large balanced samples. In this paper we propose a method for computing optimal inclusion probabilities for balanced samples. Next, we show that the optimal Neyman allocation is a particular case of this method.

  10. A balancing act for renewables

    Science.gov (United States)

    Elliott, David

    2016-01-01

    Energy storage will play a key role in increasing the use of variable energy sources. Nonetheless, storage is not the only balancing option and the overall design of power systems will incorporate a range of flexible generation, storage and grid-balancing options of different types and scales.

  11. H∞ Balancing for Nonlinear Systems

    NARCIS (Netherlands)

    Scherpen, Jacquelien M.A.

    1996-01-01

    In previously obtained balancing methods for nonlinear systems a past and a future energy function are used to bring the nonlinear system in balanced form. By considering a different pair of past and future energy functions that are related to the H∞ control problem for nonlinear systems we define H

  12. When Do States Balance Power?

    DEFF Research Database (Denmark)

    Hariri, Jacob Gerner; Wivel, Anders

    2010-01-01

    This paper explores the logic of balancing in structural realist theory. Arguably, the durability of the unipolar moment is a challenge to the logic of balancing. The paper uses the tools of microeconomics to build a mathematical model of structural realism. The simple model reiterates the...

  13. Data needs for nutrient balances

    DEFF Research Database (Denmark)

    Vinther, Finn Pilgaard

    One of the tools for evaluating the results of environmental action plans or EU directives related to nutrients in the agricultural sector is to follow the development of annually estimated nitrogen (N) and phosphorus (P) balances and surplus. Unlike greenhouse gas and ammonia emissions, countries...... are not required to report N and P balances for agriculture as part of any international conventions. As a consequence, there is no organisation equivalent to the Intergovernmental Panel on Climate Change (IPCC) or United Nations Economic Commission for Europe (UNECE) who has responsibility for...... standardising and improving the methodology to calculate such balances. However, Eurostat and OECD have jointly established a standard for using a gross N balances, and the soil N balance calculated by the CAPRI model has gained acceptance in European policymaking. It can be mentioned that the Task Force on...

  14. Tunable Reflective Spatial Heterodyne Spectrometer: A Technique for High Resolving Power, Wide Field Of View Observation Of Diffuse Emission Line Sources

    Science.gov (United States)

    Hosseini, Seyedeh Sona

    The purpose of this dissertation is to discuss the need for new technology in broadband high-resolution spectroscopy based on the emerging technique of Spatial Heterodyne Spectroscopy (SHS) and to propose new solutions that should enhance and generalize this technology to other fields. Spectroscopy is a proven tool for determining compositional and other properties of remote objects. Narrow band imaging and low resolving spectroscopic measurements provide information about composition, photochemical evolution, energy distribution and density. The extension to high resolving power provides further access to temperature, velocity, isotopic ratios, separation of blended sources, and opacity effects. In current high resolving power devices, the drawback of high-resolution spectroscopy is bound to the instrumental limitations of lower throughput, the necessity of small entrance apertures, sensitivity, field of view, and large physical instrumental size. These limitations quickly become handicapping for observation of faint and/or extended targets and for spacecraft encounters. A technique with promise for the study of faint and extended sources at high resolving power is the reflective format of the Spatial Heterodyne Spectrometer (SHS). SHS instruments are compact and naturally tailored for both high etendue (defined in section 2.2.5) and high resolving power. In contrast, to achieve similar spectral grasp, grating spectrometers require large telescopes. For reference, SHS is a cyclical interferometer that produces Fizeau fringe pattern for all other wavelengths except the tuned wavelength. The large etendue obtained by SHS instruments makes them ideal for observations of extended, low surface brightness, isolated emission line sources, while their intrinsically high spectral resolution enables one to study the dynamical and physical properties described above. This document contains four chapters. Chapter 1, introduces a class of scientific targets that formerly have

  15. Combined Viterbi Detector for a Balanced Code in Page Memories

    Institute of Scientific and Technical Information of China (English)

    Chen Duan-rong; Xie Chang-sheng; Pei Xian-deng

    2004-01-01

    Based on the two path metrics being equal at a merged node in the trellis employed to describe a Viterbi detector for the detection of data encoded with a rate 6∶8 balanced binary code in page-oriented optical memories, the combined Viterbi detector scheme is proposed to improve raw bit-error rate performance by mitigating the occurrence of a two-bit reversing error event in an estimated codeword for the balanced code. The effectiveness of the detection scheme is verified for different data quantizations using Monte Carlo simulations.

  16. Coherent (photon) vs incoherent (current) detection of multidimensional optical signals from single molecules in open junctions

    Energy Technology Data Exchange (ETDEWEB)

    Agarwalla, Bijay Kumar; Hua, Weijie; Zhang, Yu; Mukamel, Shaul [Department of Chemistry, University of California, Irvine, California 92697 (United States); Harbola, Upendra [Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012 (India)

    2015-06-07

    The nonlinear optical response of a current-carrying single molecule coupled to two metal leads and driven by a sequence of impulsive optical pulses with controllable phases and time delays is calculated. Coherent (stimulated, heterodyne) detection of photons and incoherent detection of the optically induced current are compared. Using a diagrammatic Liouville space superoperator formalism, the signals are recast in terms of molecular correlation functions which are then expanded in the many-body molecular states. Two dimensional signals in benzene-1,4-dithiol molecule show cross peaks involving charged states. The correlation between optical and charge current signal is also observed.

  17. Validity and reliability of the Nintendo Wii Balance Board for assessment of standing balance.

    Science.gov (United States)

    Clark, Ross A; Bryant, Adam L; Pua, Yonghao; McCrory, Paul; Bennell, Kim; Hunt, Michael

    2010-03-01

    Impaired standing balance has a detrimental effect on a person's functional ability and increases their risk of falling. There is currently no validated system which can precisely quantify center of pressure (COP), an important component of standing balance, while being inexpensive, portable and widely available. The Wii Balance Board (WBB) fits these criteria, and we examined its validity in comparison with the 'gold standard'-a laboratory-grade force platform (FP). Thirty subjects without lower limb pathology performed a combination of single and double leg standing balance tests with eyes open or closed on two separate occasions. Data from the WBB were acquired using a laptop computer. The test-retest reliability for COP path length for each of the testing devices, including a comparison of the WBB and FP data, was examined using intraclass correlation coefficients (ICC), Bland-Altman plots (BAP) and minimum detectable change (MDC). Both devices exhibited good to excellent COP path length test-retest reliability within-device (ICC=0.66-0.94) and between-device (ICC=0.77-0.89) on all testing protocols. Examination of the BAP revealed no relationship between the difference and the mean in any test, however the MDC values for the WBB did exceed those of the FP in three of the four tests. These findings suggest that the WBB is a valid tool for assessing standing balance. Given that the WBB is portable, widely available and a fraction of the cost of a FP, it could provide the average clinician with a standing balance assessment tool suitable for the clinical setting. PMID:20005112

  18. Highly spatially resolved velocity measurements of a turbulent channel flow by a fiber-optic heterodyne laser-Doppler velocity-profile sensor

    Energy Technology Data Exchange (ETDEWEB)

    Shirai, K.; Pfister, T.; Buettner, L.; Czarske, J. [Dresden University of Technology (TU Dresden), Department of Electrical Engineering and Information Technology, Chair for Measurement and Testing Techniques, Dresden (Germany); Mueller, H. [Physikalisch-Technische Bundesanstalt Braunschweig (PTB), Department 1.4 Gas Flow, Braunschweig (Germany); Becker, S.; Lienhart, H.; Durst, F. [Institute of Fluid Mechanics (LSTM), Friedrich-Alexander-University Erlangen-Nuernberg, Erlangen (Germany)

    2006-03-15

    Velocity measurements with a high spatial resolution are important in turbulent flow research. In this paper, we report on the development of a new fiber-optic laser-Doppler velocity-profile sensor exhibiting a spatial resolution of up to 5 {mu}m and its application to turbulent boundary layers. The sensor developed in the present work employs a frequency-division-multiplexing technique in order to separate two measurement signals from the two fringe systems. Velocity measurements close to zero at the solid wall were realized using heterodyne technique. The use of fiber optics improved a robustness of the sensor. The measurement accuracy of the sensor was experimentally investigated with respect to the spatial resolution and velocity. Universal velocity profile of a turbulent flow was obtained in a fully developed channel flow. Mean and fluctuating velocity are presented with a high spatial resolution. (orig.)

  19. On the possibility of designing a high-resolution heterodyne spectrometer for near-IR range on the basis of a tunable diode laser

    International Nuclear Information System (INIS)

    The results of heterodyning of broadband radiation in the near-IR range are presented. A stabilised DFB laser was used as a local oscillator, while the role of a broadband radiation source was played by another DFB laser, excited by the pump current below its threshold value. A fibre-optical Y-coupler based on the single-mode silica fibre served as a diplexer. The radiation mixed in the singlemode fibre was incident on the photodetector, the role of which was played by a p - i - n photodiode. The signal from the photodiode was amplified by the preamplifier with the feedback resistance 240 kΩ and the bandwidth ∼1 MHz and then digitised using a 16-digit ADC. The frequency scanning was implemented via the variation of the local oscillator frequency. The developed registration system provides the sensitivity ∼1.4 % of the shot noise value at the acquisition time ∼40 min.

  20. Development of infrared Echelle spectrograph and mid-infrared heterodyne spectrometer on a small telescope at Haleakala, Hawaii for planetary observation

    Science.gov (United States)

    Sakanoi, Takeshi; Kasaba, Yasumasa; Kagitani, Masato; Nakagawa, Hiromu; Kuhn, Jeff; Okano, Shoichi

    2014-08-01

    We report the development of infrared Echelle spectrograph covering 1 - 4 micron and mid-infrared heterodyne spectrometer around 10 micron installed on the 60-cm telescope at the summit of Haleakala, Hawaii (alt.=3000m). It is essential to carry out continuous measurement of planetary atmosphere, such as the Jovian infrared aurora and the volcanoes on Jovian satellite Io, to understand its time and spatial variations. A compact and easy-to-use high resolution infrared spectrometer provide the good opportunity to investigate these objects continuously. We are developing an Echelle spectrograph called ESPRIT: Echelle Spectrograph for Planetary Research In Tohoku university. The main target of ESPRIT is to measure the Jovian H3+ fundamental line at 3.9 micron, and H2 nu=1 at 2.1 micron. The 256x256 pixel CRC463 InSb array is used. An appropriate Echelle grating is selected to optimize at 3.9 micron and 2.1 micron for the Jovian infrared auroral observations. The pixel scale corresponds to the atmospheric seeing (0.3 arcsec/pixel). This spectrograph is characterized by a long slit field-of-view of ~ 50 arcsec with a spectral resolution is over 20,000. In addition, we recently developed a heterodyne spectrometer called MILAHI on the 60 cm telescope. MILAHI is characterized by super high-resolving power (more than 1,500,000) covering from 7 - 13 microns. Its sensitivity is 2400 K at 9.6 micron with a MCT photo diode detector of which bandwidth of 3000 MHz. ESPRIT and MILAHI is planned to be installed on 60 cm telescope is planned in 2014.

  1. Sensitive Quantitative Assessment of Balance Disorders

    Science.gov (United States)

    Paloski, Willilam H.

    2007-01-01

    Computerized dynamic posturography (CDP) has become a standard technique for objectively quantifying balance control performance, diagnosing the nature of functional impairments underlying balance disorders, and monitoring clinical treatment outcomes. We have long used CDP protocols to assess recovery of sensory-motor function in astronauts following space flight. The most reliable indicators of post-flight crew performance are the sensory organization tests (SOTs), particularly SOTs 5 and 6, which are sensitive to changes in availability and/or utilization of vestibular cues. We have noted, however, that some astronauts exhibiting obvious signs of balance impairment after flight are able to score within clinical norms on these tests, perhaps as a result of adopting competitive strategies or by their natural skills at substituting alternate sensory information sources. This insensitivity of the CDP protocol could underestimate of the degree of impairment and, perhaps, lead to premature release of those crewmembers to normal duties. To improve the sensitivity of the CDP protocol we have introduced static and dynamic head tilt SOT trials into our protocol. The pattern of postflight recovery quantified by the enhanced CDP protocol appears to more aptly track the re-integration of sensory-motor function, with recovery time increasing as the complexity of sensory-motor/biomechanical task increases. The new CDP protocol therefore seems more suitable for monitoring post-flight sensory-motor recovery and for indicating to crewmembers and flight surgeons fitness for return to duty and/or activities of daily living. There may be classes of patients (e.g., athletes, pilots) having motivation and/or performance characteristics similar to astronauts whose sensory-motor treatment outcomes would also be more accurately monitored using the enhanced CDP protocol. Furthermore, the enhanced protocol may be useful in early detection of age-related balance disorders.

  2. How Our Balance System Works

    Science.gov (United States)

    ... from your eyes, the inner ear, and the sensory systems of the body (such as the skin, muscles, ... function? How are vision, the inner ear, and sensory systems impacting functional balance? Some of the tests of ...

  3. Cautions Concerning Electronic Analytical Balances.

    Science.gov (United States)

    Johnson, Bruce B.; Wells, John D.

    1986-01-01

    Cautions chemists to be wary of ferromagnetic samples (especially magnetized samples), stray electromagnetic radiation, dusty environments, and changing weather conditions. These and other conditions may alter readings obtained from electronic analytical balances. (JN)

  4. Skylab water balance error analysis

    Science.gov (United States)

    Leonard, J. I.

    1977-01-01

    Estimates of the precision of the net water balance were obtained for the entire Skylab preflight and inflight phases as well as for the first two weeks of flight. Quantitative estimates of both total sampling errors and instrumentation errors were obtained. It was shown that measurement error is minimal in comparison to biological variability and little can be gained from improvement in analytical accuracy. In addition, a propagation of error analysis demonstrated that total water balance error could be accounted for almost entirely by the errors associated with body mass changes. Errors due to interaction between terms in the water balance equation (covariances) represented less than 10% of the total error. Overall, the analysis provides evidence that daily measurements of body water changes obtained from the indirect balance technique are reasonable, precise, and relaible. The method is not biased toward net retention or loss.

  5. An Oscillating Magnet Watt Balance

    CERN Document Server

    Ahmedov, H

    2015-01-01

    We establish the principles for a new generation of simplified and accurate watt balances in which an oscillating magnet generates Faraday's voltage in a stationary coil. A force measuring system and a mechanism providing vertical movements of the magnet are completely independent in an oscillating magnet watt balance. This remarkable feature allows to establish the link between the Planck constant and a macroscopic mass by a one single experiment. Weak dependence on variations of environmental and experimental conditions, weak sensitivity to ground vibrations and temperature changes, simple force measuring procedure, small sizes and other useful features offered by the novel approach considerably reduce the complexity of the experimental setup. We formulate the oscillating magnet watt balance principle and establish the measurement procedure for the Planck constant. We discuss the nature of oscillating magnet watt balance uncertainties and give a brief description of the National Metrology Institute (UME) wa...

  6. Laboratory Workhorse: The Analytical Balance.

    Science.gov (United States)

    Clark, Douglas W.

    1979-01-01

    This report explains the importance of various analytical balances in the water or wastewater laboratory. Stressed is the proper procedure for utilizing the equipment as well as the mechanics involved in its operation. (CS)

  7. Hatha yoga on body balance

    OpenAIRE

    Erick Tadeu Prado; Vagner Raso; Renata Coelho Scharlach; Cristiane Akemi Kasse

    2014-01-01

    Background: A good body balance requires a proper function of vestibular, visual, and somatosensory systems which can be reach with exercise practice and/or yoga. Aim: To determine the effects of a 5-month hatha yoga training program on body balance in young adults. Materials and Methods: This study used a controlled, nonrandomized design, where the experimental group underwent a 5-month training program and were then compared with the control group that had a sedentary lifestyle. A c...

  8. Risk, Balanced Skills and Entrepreneurship

    OpenAIRE

    Hsieh, C.; Parker, S.C.; Praag, van, B.

    2011-01-01

    This paper proposes that risk aversion encourages individuals to invest in balanced skill profiles, making them more likely to become entrepreneurs. By not having taken this possible linkage into account, previous research has underestimated the impacts both of risk aversion and balanced skills on the likelihood individuals choose entrepreneurship. Data on Dutch university graduates provides evidence which supports this contention. It thereby raises the possibility that even risk-averse peopl...

  9. Balancing local budgets in Romania

    OpenAIRE

    Attila GYÖRGY

    2014-01-01

    Local budgets in Romania are balanced with revenues transferred from state budget according to the criterions laid down in the Local Public Finance Act. These criterions are focusing on the financial capacity, population and surface, each local budget getting balancing amounts inversely with the administrative unit’s wellness and directly to size. The repartition algorithm is used for more than a decade, but periodically it was revised in order to be better folded to fiscal policy and economi...

  10. Electric power balance sheet 2012

    International Nuclear Information System (INIS)

    The mission of RTE, the French electricity Transportation grid, a public service assignment, is to balance the electricity supply and demand in real time. This report presents RTE's technical results for the year 2012: strong seasonal contrast of power consumption, rise of the renewable energies contribution in meeting the electricity demand, slight decay of the nuclear and thermal power generation, decrease of the export balance and change in trades structure, adaptation of RTE's network to the evolutions of the energy system

  11. Financial intermediary balance sheet management

    OpenAIRE

    Adrian,Tobias; Shin, Hyun Song

    2011-01-01

    Conventional discussions of balance sheet management by nonfinancial firms take the set of positive net present value (NPV) projects as given, which in turn determines the size of the assets of the firm. The focus is on the composition of equity and debt in funding such assets. In contrast, the balance sheet management of financial intermediaries reveals that it is equity that behaves like the predetermined variable, and the asset size of the bank or financial intermediary is determined by th...

  12. VALUE BALANCE IN CONSUMER PROTECTION

    OpenAIRE

    Dahsan Hasan

    2015-01-01

    This research aims to describe how the realization of ' Balance ' in the Consumer Protection Act, describes how the responsibility of the parties (consumers, businessmen and the Government) so that it can realize the value of the balance in the protection of consumer, Research conducted in the framework of the preparation of this dissertation is to type the socio-juridical, in addition to researching the secondary legal materials in the form of legal regulations, manual and electronic law lib...

  13. Balancer effects in opinion dynamics

    CERN Document Server

    Cheon, Taksu

    2016-01-01

    We introduce a novel type of contrarian agent, the balancer, to Galam model of opinion dynamics, in order to account for the skepticism over one-sidedness and for the sense of fairness. We find that the inclusion of balancers along with floaters and inflexibles brings about a critical point on parametric plane of the dynamical system, which results in the new kind of stable final states of the opinion dynamics, that seem to capture several intriguing features found often in mature democracies.

  14. Assessment of perioperative fluid balance

    OpenAIRE

    Bumbaširević V.; Marković D.; Vlajković G.; Sinđelić R.

    2009-01-01

    Careful assessment of the fluid balance is required in the perioperative period since appropriate fluid therapy is essential for successful patient's outcome. Haemodynamic monitoring allows understanding the physiology of the circulation and changes of fluid balance in the perioperative period. This is diagnostic aid and guide for fluid replacement therapy. Patient's volume status is frequently assessed by different haemodynamic variables that could be targeted as the endpoints for fluid ther...

  15. Form 6 - gas balancing agreement

    International Nuclear Information System (INIS)

    In 1988, a special Committee of the Rocky Mountain Mineral Law Foundation undertook a project to draft a model from gas balancing agreement. This project was initiated at the request of a number of Foundation members who felt that a model form gas balancing agreement would facilitate the negotiation of operating agreement, since gas balancing issues had become sticking points in the process. The Committee was composed of attorneys representing a wide cross-section of the oil and gas industry including both major and independent oil companies, production companies with interstate pipeline affiliates, and private practitioners. The Committee attempted to address the more controversial issues in gas balancing with optional provisions in the Form. To facilitate the negotiation process, the number of optional provisions was minimized. This form may be used as an Appendix to the new A.A.P.L. Form 610-1989 Model Form Operating Agreement. This book includes provision of this Form which are: Ownership of gas production; Balancing of production accounts; Cash balancing upon depletion; Deliverability tests; Nominations; Statements; Payment of taxes; Operating expenses; Overproducing allowable; Payment of leasehold burdens; Operator's liability; Successors and assigns; Audits; Arbitration; and Operator's fees

  16. Postural Balance in Women with Osteoporosis and Effective Factors

    Directory of Open Access Journals (Sweden)

    Duygu Ünlüsoy

    2011-08-01

    Full Text Available Introduction: The most common cause of mortality and morbidity among osteoporotic individuals is bone fracture which in many cases is a direct result of falls. Individual factors contributing to the risk of fall are poor postural balance and lack of muscle strength. Our aims were to assess postural dynamic balance in osteoporotic women and to describe the effective factors on the balance performance. Methods: Twenty osteoporotic women with kyphosis, 50 osteoporotic women without kyphosis, and 30 healthy women were included in the study. Anterior/Posterior (AP, Medial/Lateral (ML and Overall (OA stability indices were obtained using Biodex Stability System (Biodex Medical System, Shirley, NY. Subjects were tested both with eyes open and eyes closed. Quadriceps-hamstring muscles’ strength were measured with isokinetic system at angular speeds of 60-180-300°/sec. Results: OA, AP, ML stability indices in the group with osteoporosis were found to be statistically significantly higher in the open-eyed balance test. When a correlation analysis was performed on all osteoporotic patients, a negative correlation was detected between balance stability indices and knee flexion-extension strength at 60°/sec and knee flexion strength at 300°/sec. Multivariable regression analysis revealed knee extension strength at 60°/sec to be the most effective factor contributing to balance in osteoporotic patients. Conclusion: Postural balance in osteoporotic women presenting is significantly worse than in the healthy women and the factor exerting the greatest influence on balance is quadriceps muscle strength. Therefore, particular importance must be given to balance and quadriceps strengthening exercises in order to prevent falls in osteoporotic patients. (Turkish Journal of Osteoporosis 2011;17:37-43

  17. 能耗均衡的无线传感器网络的入侵检测机制%An Energy-Balancing Intrusion Detection Mechanism of Wireless Sensor Network

    Institute of Scientific and Technical Information of China (English)

    彭春燕; 杨志强; 张效娟

    2013-01-01

    Based on energy-limited and security of the wireless sensor network, a intrusion detection system is proposed based on the energy consumption of the equilibrium in wireless sensor network in this paper. At first, we put forward a cluster of WSN is divided into several Sectors, and only a few nodes are deployed with IDS. The result show that the proposed model and algorithm can reduce energy consumption effectively and improve the efficiency of the testing error data and anomalous node.%针对无线传感器网络中能量有限和安全问题,本文提出了一种基于能耗均衡的无线传感器的入侵检测机制.首先在无线传感器现有的分簇模型上划分若干Sector,然后在某些节点上部署IDS,提出入侵检测的算法,利用仿真验证了本文所提出的模型与算法,结果表明可使网络节点的能耗得到有效的降低,同时提高了检测错误数据和异常节点的准确率.

  18. VALUE BALANCE IN CONSUMER PROTECTION

    Directory of Open Access Journals (Sweden)

    Dahsan Hasan

    2015-07-01

    Full Text Available This research aims to describe how the realization of ' Balance ' in the Consumer Protection Act, describes how the responsibility of the parties (consumers, businessmen and the Government so that it can realize the value of the balance in the protection of consumer, Research conducted in the framework of the preparation of this dissertation is to type the socio-juridical, in addition to researching the secondary legal materials in the form of legal regulations, manual and electronic law library, relevant research results in the field of law of particular problems in the field of consumer protection and other written materials, as well as researching various legal facts about consumer protection which occur in the field as well as its impact on the general public. The results showed that: 1 a form of value balance in consumer protection legislation lies in the synergy between the rights and obligations the rights and obligations of consumers, businessmen, as well as the duties and responsibilities of the Government, the supporters of both public institutions and private consumers are dispute resolution Efforts, and the use of contract oversight of overall indicators are assessed if merged between the assessment of consumers and businessmen, as well as assessment of the Government then obtained 32 indicators of where the total number of indicators corresponding to the value of the balance of a total of 10 indicators, while the total number of which is not in accordance with the value of the balance as much as 21 indicators and only one indicator that his judgment balanced. So that the efforts made in the framework of the fulfilment of the rights and obligations of consumers and businessmen as well as maximize the task and responsibility of the Government is still having a lot of obstacles or not be able to realize the value of balance

  19. Ethnic Differences in Decisional Balance and Stages of Mammography Adoption

    Science.gov (United States)

    Otero-Sabogal, Regina; Stewart, Susan; Shema, Sarah J.; Pasick, Rena J.

    2007-01-01

    Behavioral theories developed through research with mainstream, English-speaking populations have been applied to ethnically diverse and underserved communities in the effort to eliminate disparities in early breast cancer detection. This study tests the validity of the transtheoretical model (TTM) decisional balance measure and the application of…

  20. Transformation rule for covariance matrices under Bell-like detections

    CERN Document Server

    Spedalieri, Gaetana; Pirandola, Stefano

    2013-01-01

    Starting from the transformation rule of a covariance matrix under homodyne detections, we can easily derive a formula for the transformation of a covariance matrix of (n+2) bosonic modes under Bell-like detections, where the last two modes are combined in an arbitrary beam splitter (i.e., with arbitrary transmissivity) and then homodyned. This formula can be specialized to describe the standard Bell detection and the heterodyne measurement, which are exploited in many contexts, including protocols of quantum teleportation, entanglement swapping and quantum cryptography. Our general formula can be adopted to study these protocols in the presence of experimental imperfections or asymmetric setups, e.g., deriving from the use of unbalanced beam splitters.

  1. Optical communication with two-photon coherent states. II - Photoemissive detection and structured receiver performance

    Science.gov (United States)

    Shapiro, J. H.; Yuen, H. P.; Machado Mata, J. A.

    1979-01-01

    In a previous paper (1978), the authors developed a method of analyzing the performance of two-photon coherent state (TCS) systems for free-space optical communications. General theorems permitting application of classical point process results to detection and estimation of signals in arbitrary quantum states were derived. The present paper examines the general problem of photoemissive detection statistics. On the basis of the photocounting theory of Kelley and Kleiner (1964) it is shown that for arbitrary pure state illumination, the resulting photocurrent is in general a self-exciting point process. The photocount statistics for first-order coherent fields reduce to those of a special class of Markov birth processes, which the authors term single-mode birth processes. These general results are applied to the structure of TCS radiation, and it is shown that the use of TCS radiation with direct or heterodyne detection results in minimal performance increments over comparable coherent-state systems. However, significant performance advantages are offered by use of TCS radiation with homodyne detection. The abstract quantum descriptions of homodyne and heterodyne detection are derived and a synthesis procedure for obtaining quantum measurements described by arbitrary TCS is given.

  2. Balancing act: the ultimate balance nutrition consulting center.

    Science.gov (United States)

    Engle, L

    1998-11-01

    Nutritional issues often complicate health care but are very important in HIV treatment where diet can play a strong role in drug absorption and effectiveness. A Canadian company has started a for-fee nutritional counseling service called Ultimate Balance. The nutritionists at Ultimate Balance require medical disclosure and extensive telephone interviews with patients, and also review patients' cases and medications. The nutritional guidance provided is controversial, because it is funded by a company that produces nutritional supplements, and counselors sometimes recommend those supplements. A personal experience with the nutritional counseling service is described. Contact information is provided. PMID:11365979

  3. Dairy Proteins and Energy Balance

    DEFF Research Database (Denmark)

    Bendtsen, Line Quist

    High protein diets affect energy balance beneficially through decreased hunger, enhanced satiety and increased energy expenditure. Dairy products are a major source of protein. Dairy proteins are comprised of two classes, casein (80%) and whey proteins (20%), which are both of high quality, but...... casein is absorbed slowly and whey is absorbed rapidly. The present PhD study investigated the effects of total dairy proteins, whey, and casein, on energy balance and the mechanisms behind any differences in the effects of the specific proteins. The results do not support the hypothesis that dairy...... proteins, whey or casein are more beneficial than other protein sources in the regulation of energy balance, and suggest that dairy proteins, whey or casein seem to play only a minor role, if any, in the prevention and treatment of obesity....

  4. Constrained Allocation Flux Balance Analysis

    CERN Document Server

    Mori, Matteo; Martin, Olivier C; De Martino, Andrea; Marinari, Enzo

    2016-01-01

    New experimental results on bacterial growth inspire a novel top-down approach to study cell metabolism, combining mass balance and proteomic constraints to extend and complement Flux Balance Analysis. We introduce here Constrained Allocation Flux Balance Analysis, CAFBA, in which the biosynthetic costs associated to growth are accounted for in an effective way through a single additional genome-wide constraint. Its roots lie in the experimentally observed pattern of proteome allocation for metabolic functions, allowing to bridge regulation and metabolism in a transparent way under the principle of growth-rate maximization. We provide a simple method to solve CAFBA efficiently and propose an "ensemble averaging" procedure to account for unknown protein costs. Applying this approach to modeling E. coli metabolism, we find that, as the growth rate increases, CAFBA solutions cross over from respiratory, growth-yield maximizing states (preferred at slow growth) to fermentative states with carbon overflow (preferr...

  5. Efficacy of virtual reality-based balance training versus the Biodex balance system training on the body balance of adults

    OpenAIRE

    Ibrahim, Manal S.; Mattar, Ayman G.; Elhafez, Salam M.

    2016-01-01

    [Purpose] This study investigated efficacy of virtual reality (VR)-based balance training on enhancing balance and postural reactions of adults as a low-cost new modality compared to the established Biodex Balance System (BBS). [Subjects] Thirty normal adults of both genders were divided randomly into two equal-sized experimental groups of 15: BBS balance training and VR balance training. [Methods] The training programmes were conducted in 12 sessions, three 15-min sessions per week. The Nint...

  6. Balanced dynamics in the Tropics

    OpenAIRE

    Verkley, W.T.M.; Velde, van der, G.

    2010-01-01

    For the shallow-water equations on an equatorial beta plane, the properties of low-frequency Rossby waves and (mixed) Rossby-gravity waves are investigated. It is shown that in the low-frequency limit the horizontal divergence of these solutions is zero and their geopotential satisfies = f, where f = y is the Coriolis parameter and is the stream function of the non-divergent velocity field. This type of balance is rather different from the geostrophic balance satisfied by Kelvin waves. It can...

  7. Heider balance in human networks

    Science.gov (United States)

    Gawroński, P.; Kułakowski, K.

    2005-07-01

    Recently, a continuous dynamics was proposed to simulate dynamics of interpersonal relations in a society represented by a fully connected graph. The final state of such a society was found to be identical with the so-called Heider balance (HB), where the society is divided into two mutually hostile groups. In the continuous model, a polarization of opinions was found in HB. Here we demonstrate that the polarization occurs also in Barabási-Albert networks, where the Heider balance is not necessarily present. In the second part of this work we demonstrate the results of our formalism, when applied to reference examples: the Southern women and the Zachary club.

  8. The social balance sheet 2005

    OpenAIRE

    Ph. Delhez; P. Heuse

    2006-01-01

    Each year, the National Bank examines the provisional results of the social balance sheets of Belgian enterprises. As the social balance sheets are not yet all available for 2005, the study is based on a limited population of enterprises, compiled according to the principle of a constant sample. This population is made up of 48,976 enterprises employing around 4,441,000 workers in 2005. The main results of the analysis are as follows. As an average, employment increased by 0.5 p.c. between 20...

  9. Femtosecond Heterodyne Transient Grating Detection of Conformational Dynamics in the S0 (11Ag-) State of Carotenoids After Nonradiative Decay of the S2 (11Bu+) State

    Science.gov (United States)

    Roscioli, Jerome D.; Ghosh, Soumen; Bishop, Michael M.; Lafountain, Amy M.; Frank, Harry A.; Beck, Warren F.

    Transient grating spectroscopy was used to study the dynamics of nonradiative decay of the S1 (21Ag-) state in ß-carotene and peridinin after optical preparation of the S2) state. The kinetics of the recovery of the absorption and dispersion components of the third-order signal exhibit significantly different time constants. For β-carotene in benzonitrile, the absorption and dispersion recovery time constants are 11.6 and 10.2 ps. For peridinin in methanol, the time constants are 9.9 and 7.4 ps. These results indicate that the initial product of the decay of the S1 state is a conformationally displaced structure. The decay rate for the S1 state and the conformational relaxation rate are both slowed in peridinin as the polarity of the solvent decreases; in ethyl acetate, the conformational relaxation time constant is 45 ps, which rules out a dominant contribution from vibrational cooling. These results indicate that the S1 state develops intramolecular charge transfer character owing to distortions along torsional and out-of-plane coordinates, with a pyramidal structure favored as the most stable conformation. Recovery of the photoselected ground state conformation involves a reverse charge-transfer event followed by relaxation to a planar structure. Work supported by Photosynthetic Systems Program of the U.S. Department of Energy under Grant DE-SC0010847.

  10. The relevance of clinical balance assessment tools to differentiate balance deficits

    OpenAIRE

    Mancini, Martina; Horak, Fay B.

    2010-01-01

    Control of balance is complex and involves maintaining postures, facilitating movement, and recovering equilibrium. Balance control consists of controlling the body center of mass over its limits of stability. Clinical balance assessment can help assess fall risk and/or determine the underlying reasons for balance disorders. Most functional balance assessment scales assess fall risk and the need for balance rehabilitation but do not differentiate types of balance deficits. A system approach t...

  11. An Improved Hadoop Data Load Balancing Algorithm

    Directory of Open Access Journals (Sweden)

    Kun Liu

    2013-12-01

    Full Text Available Data load balancing is one of the key problems of big data technology. As a big data application, Hadoop has had many successful applications. HDFS is Hadoop Distributed File System and has the load balancing procedure which can balance the storage load on each machine. However, this method cannot balance the overload rack preferentially, and so it is likely to cause the breakdown of overload machines. In this paper, we focus on the overload machines and propose an improved algorithm for balancing the overload racks preferentially. The improved method constructs Prior Balance List list which includes overload machines, For Balance List list and NextForBalanceList list by many factors and balances among the racks selected from these lists firstly. Experiments show that the improved method can balance the overload racks in time and reduce the possibility of breakdown of these racks

  12. Balancing Covariates via Propensity Score Weighting

    OpenAIRE

    Li, Fan; Morgan, Kari Lock; Zaslavsky, Alan M.

    2014-01-01

    Covariate balance is crucial for an unconfounded descriptive or causal comparison. However, lack of balance is common in observational studies. This article considers weighting strategies for balancing covariates. We define a general class of weights-the balancing weights-that balance the weighted distributions of the covariates between treatment groups. These weights incorporate the propensity score to weight each group to an analyst-selected target population. This class unifies existing we...

  13. Balance Systems and the Variational Bicomplex

    OpenAIRE

    Serge Preston

    2011-01-01

    In this work we show that the systems of balance equations (balance systems) of continuum thermodynamics occupy a natural place in the variational bicomplex formalism. We apply the vertical homotopy decomposition to get a local splitting (in a convenient domain) of a general balance system as the sum of a Lagrangian part and a complemental ''pure non-Lagrangian'' balance system. In the case when derivatives of the dynamical fields do not enter the constitutive relations of the balance system,...

  14. Energy balance invariance for interacting particle systems

    OpenAIRE

    Yavari, Arash; Marsden, Jerrold E.

    2009-01-01

    This paper studies the principle of invariance of balance of energy and its consequences for a system of interacting particles under groups of transformations. Balance of energy and its invariance is first examined in Euclidean space. Unlike the case of continuous media, it is shown that conservation and balance laws do not follow from the assumption of invariance of balance of energy under time-dependent isometries of the ambient space. However, the postulate of invariance of balance of ener...

  15. A Balanced Higher Education System

    Science.gov (United States)

    Brown, Roger

    2011-01-01

    This article explores what is meant by "a balanced higher education system". It argues that the Clarkian "triangle of coordination" (Clark, 1983) and the more recent model of Martinez and Richardson (2003) should be replaced by one that distinguishes between "self" and "collective" interests in both the academy and the wider society. Such a scheme…

  16. Balance Scorecard in Hospital Units

    OpenAIRE

    Pu?an Alina; Ivan Oana Raluca

    2014-01-01

    Balance Scorecard (BSC) is a tool for measuring the performance, used mainly in the private sector. Social and economic changes of recent years have given rise to a number of objective needs, particularly in the management of “public money”.

  17. Learning from Balance Sheet Visualization

    Science.gov (United States)

    Tanlamai, Uthai; Soongswang, Oranuj

    2011-01-01

    This exploratory study examines alternative visuals and their effect on the level of learning of balance sheet users. Executive and regular classes of graduate students majoring in information technology in business were asked to evaluate the extent of acceptance and enhanced capability of these alternative visuals toward their learning…

  18. Finding Balance in the Winds.

    Science.gov (United States)

    Wilbur, Michael

    1999-01-01

    Describes the author's experience of and reflections concerning a group workshop facilitated by Michael Tlanusta Garrett of the Eastern Band of Cherokee. Provides information about the Native American teachings and traditions of the four winds, balance, and harmony, and discusses the use of self by group leaders as a powerful therapeutic and…

  19. [Assessment of perioperative fluid balance].

    Science.gov (United States)

    Sindelić, R; Vlajković, G; Marković, D; Bumbasirević, V

    2009-01-01

    Careful assessment of the fluid balance is required in the perioperative period since appropriate fluid therapy is essential for successful patient's outcome. Haemodynamic monitoring allows understanding the physiology of the circulation and changes of fluid balance in the perioperative period. This is diagnostic aid and guide for fluid replacement therapy. Patient's volume status is frequently assessed by different haemodynamic variables that could be targeted as the endpoints for fluid therapy and resuscitation. Fluid balance is the crucial factor in the maintenance of haemodynamic stability, tissue oxygenation and organ function. When the haemodynamic monitoring is applied in a rigorous and consistent manner, it reduces mortality and length of stay as well as costs incurred. There are a number of tests which describe the effectiveness of the invasive haemodynamic monitoring procedures usage. Since the pulmonary artery catheter (PAC) had been introduced into clinical practice it was considered as a golden standard for cardiac output measurements, haemodynamic and fluid balance assessment. Nevertheless, in previous 10 years new minimally invasive and noninvasive simple techniques for haemodynamic monitoring and patient's hydroelectricity status evaluation have been developed. They can replace PAC under different clinical circumstances and some of these techniques PMID:19504992

  20. Balance and coordination after viewing stereoscopic 3D television.

    Science.gov (United States)

    Read, Jenny C A; Simonotto, Jennifer; Bohr, Iwo; Godfrey, Alan; Galna, Brook; Rochester, Lynn; Smulders, Tom V

    2015-07-01

    Manufacturers and the media have raised the possibility that viewing stereoscopic 3D television (S3D TV) may cause temporary disruption to balance and visuomotor coordination. We looked for evidence of such effects in a laboratory-based study. Four hundred and thirty-three people aged 4-82 years old carried out tests of balance and coordination before and after viewing an 80 min movie in either conventional 2D or stereoscopic 3D, while wearing two triaxial accelerometers. Accelerometry produced little evidence of any change in body motion associated with S3D TV. We found no evidence that viewing the movie in S3D causes a detectable impairment in balance or in visuomotor coordination. PMID:26587261

  1. Introductory Physics Experiments Using the Wii Balance Board

    Science.gov (United States)

    Starr, Julian; Sobczak, Robert; Iqbal, Zohaib; Ochoa, Romulo

    2010-02-01

    The Wii, a video game console by Nintendo, utilizes several different controllers, such as the Wii remote (Wiimote) and the balance board, for game-playing. The balance board was introduced in early 2008. It contains four strain gauges and has Bluetooth connectivity at a relatively low price. Thanks to available open source code, such as GlovePie, any PC with Bluetooth capability can detect the information sent out by the balance board. Based on the ease with which the forces measured by each strain gauge can be obtained, we have designed several experiments for introductory physics courses that make use of this device. We present experiments to measure the forces generated when students lift their arms with and without added weights, distribution of forces on an extended object when weights are repositioned, and other normal forces cases. The results of our experiments are compared with those predicted by Newtonian mechanics. )

  2. 26 CFR 1.167(b)-2 - Declining balance method.

    Science.gov (United States)

    2010-04-01

    ... balance Jan. 1 Acquisitions Current retirements Asset balance Dec. 31 Average balance Avg. reserve before... Acquisition Asset balance Dec. 31 Avg. balance Reserve Dec. 31, before depreciation Net depreciable...

  3. Performance and Prospects of Khayyam, A Tunable Spatial Heterodyne Spectrometer (SHS) for High Spectral Resolving Power Observation of Extended Planetary Targets in Optical Wavelengths

    Science.gov (United States)

    Hosseini, S.; Harris, W.

    2014-12-01

    We present initial results, calibration and data reduction process from observations of wide-field targets using Khayyam at Mt. Hamilton, a new instrument based on a reflective spatial heterodyne spectrometer (SHS) at the focus of the Coudé Auxiliary Telescope (CAT). SHS instruments are common path two-beam Fourier transform spectrometers that produce 2-D spatial interference patterns without the requirement for moving parts. The utility of SHS comes from its combination of a wide input acceptance angle (0.5-1°), high resolving power (of order ~105), compact format, high dynamic range, and relaxed optical tolerances compared with other interferometer designs. This combination makes them extremely useful for velocity resolved for observations of wide field targets from both small and large telescopes. This report focuses on the tunable instrument at Mt Hamilton, The CAT provides a test case for on-axis use of SHS, and the impact of the resulting field non-uniformity caused by the spider pattern will be discussed. Observations of several targets will be presented that demonstrate the capabilities of SHS, including comet C/2014 E2 (Jacques), Jupiter, and both the day sky and night glow. Raw interferometric data and transformed power spectra will be shown and evaluated in terms of instrumental stability.

  4. Uncertainty analysis for the miniaturized laser heterodyne radiometer (mini-LHR) for the measurement of carbon dioxide in the atmospheric column

    International Nuclear Information System (INIS)

    Presented here is a sensitivity analysis for the miniaturized laser heterodyne radiometer. This passive, ground-based instrument measures carbon dioxide (CO2) in the atmospheric column and has been under development at NASA/GSFC since 2009. The goal of this development is to produce a low-cost, easily-deployable instrument that can extend current ground measurement networks in order to (1) validate column satellite observations, (2) provide coverage in regions of limited satellite observations, (3) target regions of interest such as thawing permafrost, and (4) support the continuity of a long-term climate record. In this paper an uncertainty analysis of the instrument performance is presented and compared with results from three sets of field measurements. The signal-to-noise ratio (SNR) and corresponding maximum uncertainty for a single scan are calculated to be 329.4 ± 1.3 by deploying error propagation through the equation governing the SNR. Reported is an absorbance noise of 0.0024 for six averaged scans of field data, for an instrument precision of 0.14 ppmv for CO2. (paper)

  5. A high sensitivity heterodyne interferometer as a possible optical readout for the LISA gravitational reference sensor and its application to technology verification

    International Nuclear Information System (INIS)

    The space-based gravitational wave detector LISA (Laser Interferometer Space Antenna) utilizes a high performance position sensor in order to measure the translation and tilt of the free flying proof mass with respect to the optical bench. Depending on the LISA optical bench design, this position sensor must have up to pm/√Hz sensitivity for the translation measurement and up to nrad/√Hz sensitivity for the tilt measurement. We developed a heterodyne interferometer, combined with differential wavefront sensing, for the tilt measurement. The interferometer design exhibits maximum symmetry where measurement and reference arm have the same frequency and polarization and the same optical path-lengths. The interferometer can be set up free of polarizing optical components preventing possible problems with thermal dependencies not suitable for the space environment. We developed a mechanically highly stable and compact setup which is located in a vacuum chamber. We measured initial noise levels below 10 pm/√Hz (longitudinal measurement) for frequencies above 10 mHz and below 20 nrad/√Hz (tilt measurement) for frequencies above 1 mHz. This setup can also be used for other applications, for example the measurement of the coefficient of thermal expansion (CTE) of structural materials, such as carbon fiber reinforced plastic (CFRP).

  6. LOAD BALANCING WITH NEURAL NETWORK

    Directory of Open Access Journals (Sweden)

    Nada M. Al Sallami

    2013-11-01

    Full Text Available This paper discusses a proposed load balance technique based on artificial neural network. It distributes workload equally across all the nodes by using back propagation learning algorithm to train feed forward Artificial Neural Network (ANN. The proposed technique is simple and it can work efficiently when effective training sets are used. ANN predicts the demand and thus allocates resources according to that demand. Thus, it always maintains the active servers according to current demand, which results in low energy consumption than the conservative approach of over-provisioning. Furthermore, high utilization of server results in more power consumption, server running at higher utilization can process more workload with similar power usage. Finally the existing load balancing techniques in cloud computing are discussed and compared with the proposed technique based on various parameters like performance, scalability, associated overhead... etc. In addition energy consumption and carbon emission perspective are also considered to satisfy green computing.

  7. Universally Balanced Combinatorial Optimization Games

    Directory of Open Access Journals (Sweden)

    Xiaotie Deng

    2010-09-01

    Full Text Available This article surveys studies on universally balanced properties of cooperative games defined in a succinct form. In particular, we focus on combinatorial optimization games in which the values to coalitions are defined through linear optimization programs, possibly combinatorial, that is subject to integer constraints. In economic settings, the integer requirement reflects some forms of indivisibility. We are interested in the classes of games that guarantee a non-empty core no matter what are the admissible values assigned to the parameters defining these programs. We call such classes universally balanced. We present characterization and complexity results on the universally balancedness property for some classes of interesting combinatorial optimization games. In particular, we focus on the algorithmic properties for identifying universally balancedness for the games under discussion.

  8. Double-yoke balanced compressor

    International Nuclear Information System (INIS)

    A double-yoke balanced compressor for a cryogenic cooler that has only linear motion imparted to balanced piston and cylinder masses. A piston yoke is driven in the linear stroke direction by a piston axially offset crankshaft cam and a cylinder yoke is driven linearly by a cylinder axially offset crankshaft cam that is exactly offset 1800 from the other cam. A large circular bushing in the compressor housing covers the entire outer cylinder head during linear operation to prevent blow by and to guide the cylinder linearly. The lower portion of the piston and cylinder connecting rods fit into linear guides that are further comprised of low molecular weight gas filled cavities to provide additional air bearing smoothness to the linear motion of the piston and cylinder

  9. Energy balance in coronal funnels

    Science.gov (United States)

    Rabin, Douglas

    1991-01-01

    The energy balance in magnetic flux tubes is examined semianalytically for the case in which thermal conduction balances radiation or in which enthalpy transport occurs. Different values are considered for areal constriction, shape, length, and maximum temperature. The overall energy budget of the solar corona is not significantly affected by magnetic constriction. A bowl-shaped funnel with a constriction factor of 4 describes the empirical differential-emission measure for log-T values between approximately 5.3 and 6.0. Loop-scaling relationships are derived for the full range of models to illustrate the dependence of the constant of proportionality on the properties of the magnetic constriction. Constriction can reduce the total energy requirement of the funnel by a factor of 5 and not affect the differential emission in flow-dominated models.

  10. Balancing energy flexibilities through aggregation

    DEFF Research Database (Denmark)

    Valsomatzis, Emmanouil; Hose, Katja; Pedersen, Torben Bach

    2014-01-01

    in both energy production and consumption, is the key to solving these problems. Flexibilities can be expressed as flex-offers, which due to their high number need to be aggregated to reduce the complexity of energy scheduling. In this paper, we discuss balance aggregation techniques that already......One of the main goals of recent developments in the Smart Grid area is to increase the use of renewable energy sources. These sources are characterized by energy fluctuations that might lead to energy imbalances and congestions in the electricity grid. Exploiting inherent flexibilities, which exist...... during aggregation aim at balancing flexibilities in production and consumption to reduce the probability of congestions and reduce the complexity of scheduling. We present results of our extensive experiments....

  11. Human balance, the evolution of bipedalism and dysequilibrium syndrome.

    Science.gov (United States)

    Skoyles, John R

    2006-01-01

    A new model of the uniqueness, nature and evolution of human bipedality is presented in the context of the etiology of the balance disorder of dysequilibrium syndrome. Human bipedality is biologically novel in several remarkable respects. Humans are (a) obligate, habitual and diverse in their bipedalism, (b) hold their body carriage spinally erect in a multisegmental "antigravity pole", (c) use their forelimbs exclusively for nonlocomotion, (d) support their body weight exclusively by vertical balance and normally never use prehensile holds. Further, human bipedalism is combined with (e) upper body actions that quickly shift the body's center of mass (e.g. tennis serves, piggy-back carrying of children), (f) use transient unstable erect positions (dance, kicking and fighting), (g) body height that makes falls injurious, (h) stiff gait walking, and (i) endurance running. Underlying these novelties, I conjecture, is a species specific human vertical balance faculty. This faculty synchronizes any action with a skeletomuscular adjustment that corrects its potential destabilizing impact upon the projection of the body's center of mass over its foot support. The balance faculty depends upon internal models of the erect vertical body's geometrical relationship (and its deviations) to its support base. Due to the situation that humans are obligate erect terrestrial animals, two frameworks - the body- and gravity-defined frameworks - are in constant alignment in the vertical z-axis. This alignment allows human balance to adapt egocentric body cognitions to detect body deviations from the gravitational vertical. This link between human balance and the processing of geometrical orientation, I propose, accounts for the close link between balance and spatial cognition found in the cerebral cortex. I argue that cortical areas processing the spatial and other cognitions needed to enable vertical balance was an important reason for brain size expansion of Homo erectus. A novel

  12. Balanced Unemployment in Polish Economy

    OpenAIRE

    Kamila Szymańska

    2009-01-01

    The article deals with the problem of balanced unemployment in relation to the Polish economy. This issue with its variety considerations and economic, social and political implications is today one of the most important matter. Author analyses this problem together with its reasons and refer it to the Polish economy. In first and second part of the text there are presented basic assumptions of natural unemployment theory and Non-Accelerating Inflation Rate of Unemployment. Third part is an a...

  13. Balance of International Payments Matters!

    Institute of Scientific and Technical Information of China (English)

    Li Zhen

    2010-01-01

    @@ For decades, China's export-oriented economic growth pattern has been constantly criticized as the culprit that destroys the world economic balance. Especially,at a time when the most serious economic crisis ever since the Great Depression is about to end, outcries from economically developed countries that China should do more to rebalance global economy have frequently made the headlines of various media coverage.

  14. Universally Balanced Combinatorial Optimization Games

    OpenAIRE

    Xiaotie Deng; Gabrielle Demange

    2010-01-01

    This article surveys studies on universally balanced properties of cooperative games defined in a succinct form. In particular, we focus on combinatorial optimization games in which the values to coalitions are defined through linear optimization programs, possibly combinatorial, that is subject to integer constraints. In economic settings, the integer requirement reflects some forms of indivisibility. We are interested in the classes of games that guarantee a non-empty core no matter what ar...

  15. Balanced input-output assignment

    Science.gov (United States)

    Gawronski, W.; Hadaegh, F. Y.

    1989-01-01

    Actuator/sensor locations and balanced representations of linear systems are considered for a given set of controllability and observability grammians. The case of equally controlled and observed states is given special attention. The assignability of grammians is examined, and the conditions for their existence are presented, along with several algorithms for their determination. Although an arbitrary positive semidefinite matrix is not always assignable, the identity grammian is shown to be always assignable. The results are extended to the case of flexible structures.

  16. Carbon balance in Mediterranean ecosystems

    OpenAIRE

    Correia, Alexandra Cristina Pires

    2013-01-01

    Forests play an important role in climate change mitigation as they sequester and store carbon dioxide (CO2) from the atmosphere. The aim of this thesis was to investigate forest carbon balance in its main compartments: tress, understory and soils. We present methods to estimate carbon stock in biomass of stone pine stands in south Portugal. Allometric models, as well as conversion and expansion factors were presented allowing the quantification of stand carbon stocks irrespect...

  17. Momentum balance in wall jets

    Science.gov (United States)

    Johansson, T. Gunnar; Mehdi, Faraz; Naughton, Jonathan W.

    2012-11-01

    A plane wall jet experiment has been done to study its momentum balance. Two component laser Doppler anemometry was used to simultaneously measure the axial and wall-normal velocity components in 6 axial positions (x/H= 25, 50, 75, 100, 125 and 150) spanning from the wall all the way well into the ambient stagnant area. In this way not only the mean velocity components and Reynolds normal and shear stresses but also all their spatial derivatives were determined. In addition the wall shear stress was measured in all six axial positions using oil film interferometry. From these data all terms in the x-momentum equation, except the pressure term, could be evaluated. Later also the pressure was measured in the same profiles, and thereby also the pressure term was included in the balance. Contrary to common belief it was found that the pressure was not constant in the wall jet. The complete momentum balance is discussed and used to evaluate the roles played by the different contributing terms in different regions of the flow field in an effort to improve on our understanding of the mechanics of wall jets.

  18. Constrained Allocation Flux Balance Analysis

    Science.gov (United States)

    Mori, Matteo; Hwa, Terence; Martin, Olivier C.

    2016-01-01

    New experimental results on bacterial growth inspire a novel top-down approach to study cell metabolism, combining mass balance and proteomic constraints to extend and complement Flux Balance Analysis. We introduce here Constrained Allocation Flux Balance Analysis, CAFBA, in which the biosynthetic costs associated to growth are accounted for in an effective way through a single additional genome-wide constraint. Its roots lie in the experimentally observed pattern of proteome allocation for metabolic functions, allowing to bridge regulation and metabolism in a transparent way under the principle of growth-rate maximization. We provide a simple method to solve CAFBA efficiently and propose an “ensemble averaging” procedure to account for unknown protein costs. Applying this approach to modeling E. coli metabolism, we find that, as the growth rate increases, CAFBA solutions cross over from respiratory, growth-yield maximizing states (preferred at slow growth) to fermentative states with carbon overflow (preferred at fast growth). In addition, CAFBA allows for quantitatively accurate predictions on the rate of acetate excretion and growth yield based on only 3 parameters determined by empirical growth laws. PMID:27355325

  19. Efficacy of virtual reality-based balance training versus the Biodex balance system training on the body balance of adults

    Science.gov (United States)

    Ibrahim, Manal S.; Mattar, Ayman G.; Elhafez, Salam M.

    2016-01-01

    [Purpose] This study investigated efficacy of virtual reality (VR)-based balance training on enhancing balance and postural reactions of adults as a low-cost new modality compared to the established Biodex Balance System (BBS). [Subjects] Thirty normal adults of both genders were divided randomly into two equal-sized experimental groups of 15: BBS balance training and VR balance training. [Methods] The training programmes were conducted in 12 sessions, three 15-min sessions per week. The Nintendo® Wii Fit Plus (NWFP) and its balance board were used to train of the VR group. Each participant answered a questionnaire concerning usability, enjoyment, balance improvement, and fatigue at the end of the training programs. [Results] The study found a significant increase the measure of mean overall balance (OLB) in both groups. No significant difference was found between the groups, but a significant decrease in the mean balance-test time was found for both groups, with no significant difference between the two training methods. The VR programme was rated highly enjoyable by 81.8% of the group. [Conclusion] The Wii Fit Plus system with the balance board as a new VR balance-training technique, can be considered an effective and enjoyable tool for the training of adults’ body balance. PMID:26957722

  20. Efficacy of virtual reality-based balance training versus the Biodex balance system training on the body balance of adults.

    Science.gov (United States)

    Ibrahim, Manal S; Mattar, Ayman G; Elhafez, Salam M

    2016-01-01

    [Purpose] This study investigated efficacy of virtual reality (VR)-based balance training on enhancing balance and postural reactions of adults as a low-cost new modality compared to the established Biodex Balance System (BBS). [Subjects] Thirty normal adults of both genders were divided randomly into two equal-sized experimental groups of 15: BBS balance training and VR balance training. [Methods] The training programmes were conducted in 12 sessions, three 15-min sessions per week. The Nintendo(®) Wii Fit Plus (NWFP) and its balance board were used to train of the VR group. Each participant answered a questionnaire concerning usability, enjoyment, balance improvement, and fatigue at the end of the training programs. [Results] The study found a significant increase the measure of mean overall balance (OLB) in both groups. No significant difference was found between the groups, but a significant decrease in the mean balance-test time was found for both groups, with no significant difference between the two training methods. The VR programme was rated highly enjoyable by 81.8% of the group. [Conclusion] The Wii Fit Plus system with the balance board as a new VR balance-training technique, can be considered an effective and enjoyable tool for the training of adults' body balance. PMID:26957722

  1. Towards balanced development in Pakistan.

    Science.gov (United States)

    Pyatt, G

    1992-01-01

    Pakistan is a country whose economic growth is surprising in light of its social indicators. The aim of this article is to examine why conditions are such and to develop a framework for understanding the issues as an aid to redesigning policies. 5 sections are devoted to a summary of the main findings, the diagnosis of development and the impact on social sectors, a proposal for balanced development, and implications for policy changes. A sound macro economic context is needed with reforms economically in price and incentive systems, institutionally, and in the law and order sector. Public administration needs to be improved and individual opportunities need to be expanded. Internal security needs to be secured, so that law and order are restored. Economic growth has been high between 1960 and 1988, due to exploitation of natural resources and cheap unskilled labor, expansion of irrigated land, and growth of the unregulated informal sector. The major constraints on economic growth will come from a lack of fiscal discipline. 40% of government revenues are consumed by the military and 20% for servicing debt. Other constraints are the population growth rate in excess of 3%/year, an urban bias in allocation of resources, neglected primary education, and gender bias in education. There has been little incentive for provincial governments to balance budgets, and civil service has become disorganized. Balanced development entails recognizing human capital, natural resources, and infrastructure; accepting the status quo; and creating and maintaining an institutional framework to correct market failures and promote individual opportunities. The environmental polluter must pay. Income must be increased through higher wages, increasing the demand for labor, and transfers to households in the form of food rations, schooling, and medical care. Investment in women will increase household earnings, and improve living conditions and the health of themselves and their children

  2. Pitfalls in Using the Balanced Scorecard

    DEFF Research Database (Denmark)

    Nørreklit, Hanne; Jakobsen, Morten; Mitchell, Falconer

    2008-01-01

    The balanced scorecard has quickly become a leading management tool. But business performance measurement is notoriously difficult, so any system, including the balanced scorecard, is likely to have unanticipated and often dysfunctional consequences. This article briefly reviews the main attracti...

  3. On Water Balance of the Black Sea

    International Nuclear Information System (INIS)

    We consider the problems concerning the water balance of the Black Sea. According to the new data river discharge is determined on the basis of which component elements of water balance are adjusted. (authors)

  4. Fast balanced sampling for highly stratified population

    OpenAIRE

    Hasler, Caren; Tillé, Yves

    2016-01-01

    Balanced sampling is a very efficient sampling design when the variable of interest is correlated to the auxiliary variables on which the sample is balanced. A procedure to select balanced samples in a stratified population has previously been proposed. Unfortunately, this procedure becomes very slow as the number of strata increases and it even fails to select samples for some large numbers of strata. A new algorithm to select balanced samples in a stratified population is proposed. This new...

  5. IMPLEMENTASI BALANCED SCORECARD PADA ORGANISASI PUBLIK

    OpenAIRE

    Imelda R. H. N Imelda R. H. N

    2004-01-01

    At first introduced, balance scorecard is used by bussiness organization to measure performance of their activities, now balance scorecard is also used by public organization. A Public Organization is an organization intends to provide services to public, not for seeking profits. In order to used by public organization, a balance scorecard need to be modified. This essay discusses how to build a balance scorecard, which includes strategic goals, measures, targets, initiatives, and implementin...

  6. The Balanced Cube: A Concurrent Data Structure

    OpenAIRE

    Dally, William J.; Seitz, Charles L.

    1985-01-01

    This paper describee the balanced cube, a new data structure for implementing ordered seta. Conventional dats structures such as heaps, balanced trees and B-trees have root bottlenecks which limit their potential concurrency and make them unable to take advantage of the computing potential of concurrent machines. The balanced cube achieves greater concurrency by eliminating the root bottleneck; an operation in the balanced cube can be initiated from any node. The throughput of ...

  7. Computational imaging with a balanced detector.

    Science.gov (United States)

    Soldevila, F; Clemente, P; Tajahuerce, E; Uribe-Patarroyo, N; Andrés, P; Lancis, J

    2016-01-01

    Single-pixel cameras allow to obtain images in a wide range of challenging scenarios, including broad regions of the electromagnetic spectrum and through scattering media. However, there still exist several drawbacks that single-pixel architectures must address, such as acquisition speed and imaging in the presence of ambient light. In this work we introduce balanced detection in combination with simultaneous complementary illumination in a single-pixel camera. This approach enables to acquire information even when the power of the parasite signal is higher than the signal itself. Furthermore, this novel detection scheme increases both the frame rate and the signal-to-noise ratio of the system. By means of a fast digital micromirror device together with a low numerical aperture collecting system, we are able to produce a live-feed video with a resolution of 64 × 64 pixels at 5 Hz. With advanced undersampling techniques, such as compressive sensing, we can acquire information at rates of 25 Hz. By using this strategy, we foresee real-time biological imaging with large area detectors in conditions where array sensors are unable to operate properly, such as infrared imaging and dealing with objects embedded in turbid media. PMID:27353733

  8. Monte Carlo methods beyond detailed balance

    NARCIS (Netherlands)

    Schram, Raoul D.; Barkema, Gerard T.

    2015-01-01

    Monte Carlo algorithms are nearly always based on the concept of detailed balance and ergodicity. In this paper we focus on algorithms that do not satisfy detailed balance. We introduce a general method for designing non-detailed balance algorithms, starting from a conventional algorithm satisfying

  9. Balancing of Lossless and Passive Systems

    NARCIS (Netherlands)

    Schaft, Arjan van der

    2008-01-01

    Different balancing techniques are applied to lossless nonlinear systems, with open-loop balancing applied to their scattering representation. It is shown that they all lead to the same result: the pair of to-be-balanced functions is given by two copies of the physical energy function, yielding thus

  10. A novel phase noise suppression method for coherent detection by utilizing two adjacent longitudinal modes generated from a supercontinuum multi-wavelength source

    Energy Technology Data Exchange (ETDEWEB)

    Pan, D; Ke, C J; Zhu, X H; Liu, D M, E-mail: cjke@mail.hust.edu.cn [College of Optoelectronic Science and Engineering, Huazhong University of Science and Technology, 430074, Wuhan (China)

    2011-02-01

    A novel phase noise suppression method for coherent detection is proposed. It uses two adjacent longitudinal modes of a multi-wavelength source, as signal light and coherent light respectively, which are both launched into the optical fiber. And heterodyne synchronous demodulation structure is used in the receiver. The performance of a back-to-back system with 100 Gbit/s NRZ-QPSK utilizing this novel method is investigated by VPI. The simulation results show that phase noise in this coherent detection scheme is suppressed significantly, which is resulted from the correlating phase and fixed frequency spacing of adjacent longitudinal modes.

  11. Hidden corrosion detection in aircraft aluminum structures using laser ultrasonics and wavelet transform signal analysis.

    Science.gov (United States)

    Silva, M Z; Gouyon, R; Lepoutre, F

    2003-06-01

    Preliminary results of hidden corrosion detection in aircraft aluminum structures using a noncontact laser based ultrasonic technique are presented. A short laser pulse focused to a line spot is used as a broadband source of ultrasonic guided waves in an aluminum 2024 sample cut from an aircraft structure and prepared with artificially corroded circular areas on its back surface. The out of plane surface displacements produced by the propagating ultrasonic waves were detected with a heterodyne Mach-Zehnder interferometer. Time-frequency analysis of the signals using a continuous wavelet transform allowed the identification of the generated Lamb modes by comparison with the calculated dispersion curves. The presence of back surface corrosion was detected by noting the loss of the S(1) mode near its cutoff frequency. This method is applicable to fast scanning inspection techniques and it is particularly suited for early corrosion detection. PMID:12782263

  12. Full characterization and analysis of a terahertz heterodyne receiver based on a NbN hot electron bolometer

    OpenAIRE

    Hajenius, M.; Baselmans, J.J.A.; Baryshev, A; Gao, J. R.; Klapwijk, T. M.; Kooi, J. W.; Jellema, W.; Yang, Z. Q.

    2006-01-01

    We present a complete experimental characterization of a quasioptical twin-slot antenna coupled small area (1.0×0.15 µm^2) NbN hot electron bolometer (HEB) mixer compatible with currently available solid state tunable local oscillator (LO) sources. The required LO power absorbed in the HEB is analyzed in detail and equals only 25 nW. Due to the small HEB volume and wide antenna bandwidth, an unwanted direct detection effect is observed which decreases the apparent sensitivity. Correcting for ...

  13. Energy balances for power plants

    International Nuclear Information System (INIS)

    An important aspect of a power plant is its energy balance, i.e. the electrical energy produced by the plant over its overall operation period, compared to the amount of non-renewable energy used to create and build the plant. Tense discussions took place in the past between criticizers and promotors of a given technology, some technologies even being accused of having a negative energy balance. Mostly based on built examples the present study aims at giving objective data for the represented technologies, as follows: a 64 MW hydro power plant in the Alps, with seasonal water storage in a lake; a 60 MW run-of-river high-head hydro power plant in the Alps; two run-of-river low-head hydro power plants in the Swiss Midlands (14 MW and 25 MW respectively); a small 30 kW wind power generator located near the Simplon Pass at 2000 m over sea level, in the Alps; a 3 kW photovoltaic generator in the roof of a single-family house; a 500 kW photovoltaic power plant in the Jura, at 1000 m over sea level; a 0.9 MWel/8.8 MWtherm fossil-fuel co-generation plant near Zuerich; a 200 MW natural-gas-fired gas/vapour turbine power plant; a 300 MW heavy-fuel-fired power plant; a 500 MW coal-fired power plant; and the Leibstadt 990 MW nuclear power plant. The best energy balances are obtained for the hydro power plants, the worst for the Leibstadt nuclear power plant. In between the photovoltaic plants and the fossil-fuel-fired plants are found. The figures differ by more than two orders of magnitude

  14. Effectiveness of the Balanced Scorecard

    DEFF Research Database (Denmark)

    Lichen, Alex Yu; Perera, Sujatha; Crowe, Susan

    2008-01-01

    Many of the claimed benefits of the Balanced Scorecard (BSC) rely on the linkage of its performance measures to strategy and on causal relations among its measures. Using a survey research method, this study examines the extent to which adopters of BSC consider these features and whether they...... result in more effective performance measurement systems. A survey of medium and large Australian manufacturing organisations reveals that varying forms of scorecards are used in practice and that managers who perceive that their scorecard measures are linked to strategy and affect each other in a causal...

  15. Character Balance in MOBA Games

    OpenAIRE

    Teodor, Norén; Emanuel, Palm

    2015-01-01

    As live streaming of video games has become easier, electronic sports have grown quickly and they are still increasing as tournaments grow in viewers and prizes. The purpose of this paper is to examine the theory Metagame Bounds by applying it to League of Legends and Dota 2, to see if it is a valid way of looking at character balance in the Multiplayer Online Battle Arena game genre. The main mode of both games consist of matches played on a map where a team of five players is up against ano...

  16. Electronic Elections: A Balancing Act

    Science.gov (United States)

    Rezende, Pedro A. D.

    This article aims to share some major lessons learned from the pioneering experience in Brazil with the world's first full national implementation of universal electronic voting. Differing notions of security, and their "collateral entanglements", appear to play a key role and are contrasted in Brazil's pioneering electronic voting saga. After an introduction, we puzzle through what election security may mean. We elaborate on how technological innovations may affect the underlying risks, their nature, corrections and balance. Then we describe some ways in which innovations have been deployed and validated, and how the results are being perceived, before some closing remarks.

  17. The Balance Idea of Integration

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ Changes in the content of European balance constitute the biggest difference between the economic integration model and its predecessors. Armament, territory and resources were considered as key factors for enhanced strength and sustained power parity with other nations. Transition to economic integration has however entailed decoupling of the two. Enhanced national strength now aims instead at power parity and shared power based on common European interests and inter-dependency rather than at weakening other nations. As a result, state relations there are moving toward fusion and convergence.

  18. Equilibria in Load Balancing Games

    Institute of Scientific and Technical Information of China (English)

    Bo Chen

    2009-01-01

    A Nash equilibrium (NE) in a multi-agent game is a strategy profile that is resilient to unilateral deviations.A strong Nash equilibrium (SE) is one that is stable against coordinated deviations of any coalition.We show that,in the load balancing games,NEs approximate SEs in the sense that the benefit of each member of any coalition from coordinated deviations is well limited.Furthermore,we show that an easily recognizable special subset of NEs exhibit even better approximation of SEs.

  19. Energy balances of OECD countries

    International Nuclear Information System (INIS)

    Contains a compilation of data on the supply and consumption of coal, oil, gas, electricity, heat, combustible renewable and waste presented in energy balances. The figures are expressed in million tonnes of oil equivalent. Historical tables summarize key energy and economic indicators as well as production, trade and final consumption data. Each issue includes definitions of products and flows and explanatory notes on the individual country data as well as conversion factors from original units to tonnes of oil equivalent. In the 1997 edition, key indicators have been provided back to 1960 instead of 1971 as in the previous editions. (author)

  20. Biasable, Balanced, Fundamental Submillimeter Monolithic Membrane Mixer

    Science.gov (United States)

    Siegel, Peter; Schlecht, Erich; Mehdi, Imran; Gill, John; Velebir, James; Tsang, Raymond; Dengler, Robert; Lin, Robert

    2010-01-01

    This device is a biasable, submillimeter-wave, balanced mixer fabricated using JPL s monolithic membrane process a simplified version of planar membrane technology. The primary target application is instrumentation used for analysis of atmospheric constituents, pressure, temperature, winds, and other physical and chemical properties of the atmospheres of planets and comets. Other applications include high-sensitivity gas detection and analysis. This innovation uses a balanced configuration of two diodes allowing the radio frequency (RF) signal and local oscillator (LO) inputs to be separated. This removes the need for external diplexers that are inherently narrowband, bulky, and require mechanical tuning to change frequency. Additionally, this mixer uses DC bias-ability to improve its performance and versatility. In order to solve problems relating to circuit size, the GaAs membrane process was created. As much of the circuitry as possible is fabricated on-chip, making the circuit monolithic. The remainder of the circuitry is precision-machined into a waveguide block that holds the GaAs circuit. The most critical alignments are performed using micron-scale semiconductor technology, enabling wide bandwidth and high operating frequencies. The balanced mixer gets superior performance with less than 2 mW of LO power. This can be provided by a simple two-stage multiplier chain following an amplifier at around 90 GHz. Further, the diodes are arranged so that they can be biased. Biasing pushes the diodes closer to their switching voltage, so that less LO power is required to switch the diodes on and off. In the photo, the diodes are at the right end of the circuit. The LO comes from the waveguide at the right into a reduced-height section containing the diodes. Because the diodes are in series to the LO signal, they are both turned on and off simultaneously once per LO cycle. Conversely, the RF signal is picked up from the RF waveguide by the probe at the left, and flows

  1. Engine balance apparatus and accessory drive device

    Science.gov (United States)

    Brogdon, James William (Inventor); Gill, David Keith (Inventor)

    2000-01-01

    A balancing mechanism for an engine that has a rotating crankshaft and reciprocating pistons such as those engines used in automobiles, aircrafts, boats, piston-driven compressors, piston-driven slider crank mechanisms, etc. The present balancing mechanism may comprise a first balance mass non-rotatably affixed to the crankshaft and a second balance mass rotatably supported on the crankshaft. A driver assembly is affixed to crankshaft to cause the second balance mass to rotate in a direction that is opposite to the direction in which the crank shaft is rotating. The driver assembly may include auxiliary gears configured to transport rotary power to auxiliary components.

  2. The balanced tensor product of module categories

    OpenAIRE

    Douglas, Christopher L.; Schommer-Pries, Christopher; Snyder, Noah

    2014-01-01

    The balanced tensor product M (x)_A N of two modules over an algebra A is the vector space corepresenting A-balanced bilinear maps out of the product M x N. The balanced tensor product M [x]_C N of two module categories over a monoidal linear category C is the linear category corepresenting C-balanced right-exact bilinear functors out of the product category M x N. We show that the balanced tensor product can be realized as a category of bimodule objects in C, provided the monoidal linear cat...

  3. Establishing Normative Values for the Barnett Balance Assessment Tool: A Preliminary Study

    Directory of Open Access Journals (Sweden)

    Monica L. Cercone MSOTS

    2014-04-01

    Full Text Available The purpose of this study was to establish normative data for the Barnett Balance Assessment (BBA for individuals ages 18-70+ years. The BBA is a newly developed assessment tool that may address limitations present in other assessments currently used to detect balance deficits. The BBA was administered to 141 participants who had no history of medical issues that could impact balance. A review of the normative data collected indicated little variation in total assessment scores in the age categories of 18-29, 30-39, and 40-49, due to the presence of a ceiling effect. Variations existed in scores among participants in the remaining age categories (50-59, 60-69, and 70+. These findings may imply that the BBA has its greatest discriminative power in assessing individuals with impaired balance, and/or that the BBA is not sensitive enough to detect differences in individuals with mild balance impairments. The researchers suggest future studies be conducted with the BBA to establish norms with populations with known orthopedic or neurological conditions that may impair balance. Results of these studies could then be compared with the baseline data gathered in this study to determine the BBA’s usefulness in detecting balance impairments with clinical populations.

  4. IMPLEMENTASI BALANCED SCORECARD PADA ORGANISASI PUBLIK

    Directory of Open Access Journals (Sweden)

    Imelda R. H. N Imelda R. H. N

    2004-01-01

    Full Text Available At first introduced, balance scorecard is used by bussiness organization to measure performance of their activities, now balance scorecard is also used by public organization. A Public Organization is an organization intends to provide services to public, not for seeking profits. In order to used by public organization, a balance scorecard need to be modified. This essay discusses how to build a balance scorecard, which includes strategic goals, measures, targets, initiatives, and implementing balance scorecard to public organization. Abstract in Bahasa Indonesia : Saat pertama kali diperkenalkan, balanced scorecard digunakan oleh organisasi bisnis untuk pengukuran kinerja. Dewasa ini, balanced scorecard tidak saja digunakan oleh organisasi bisnis tetapi juga organisasi publik. Organisasi publik adalah organisasi yang menyediakan jasa pada masyarakat dengan tujuan bukan untuk mencari profit. Untuk dapat digunakan oleh organisasi publik, balanced scorecard tersebut harus dimodifikasi. Tulisan ini membahas bagaimana membangun balanced scorecard, meliputi menentukan tujuan strategis, ukuran yang digunakan, target yang ingin dicapai serta inisiatif, dan mengimplementasikan balanced scorecard pada organisasi publik. Kata kunci: balanced scorecard, organisasi publik.

  5. Impact of rapeseed cropping on the soil carbon balance

    Science.gov (United States)

    Moffat, Antje Maria; Herbst, Mathias; Huth, Vytas; Andres, Monique; Augustin, Jürgen

    2015-04-01

    Winter oilseed rape is the dominant biofuel crop in the young moraine landscape in Northern Germany. Since the cultivation of biofuel crops requires sustainability compared to fossil fuels by law, detailed knowledge about their green house gas (GHG) balance is necessary. The soil carbon balance is one of the key contributors to the total GHG balance and also very important for the assessment of soil fertility. However, the knowledge about the impact of different management practices on the soil carbon balance is very limited up to now. Therefore, we investigated the carbon fluxes of winter oilseed rape at field plots near Dedelow/Uckermark in NE Germany with different treatments of fertilization (mineral versus organic) and tillage (no-till and mulch-till versus ploughing). The dynamics of the carbon fluxes are mainly driven by the current climatic conditions but the overall response depends strongly on the ecosystem state (with its physiological and microbiological properties) which is affected by management. To get the full carbon flux dynamics but also the impact of the different management practices, two different approaches were used: The eddy covariance technique to get continuous fluxes throughout the year and the manual chamber technique to detect flux differences between specific management practices. The manual chamber measurements were conducted four-weekly as all-day campaigns using a flow-through non-steady-state closed chamber system. The fluxes in-between campaigns were gap-filled based on functional relationships with soil and air temperature (for the ecosystem respiration) and photosynthetic active radiation (for the gross primary production). All results presented refer to the cropping season 2012-2013. The combination of the two measurement techniques allows the evaluation of chamber fluxes including an independent estimate of the error on the overall balances. Despite the considerable errors, there are significant differences in the soil carbon

  6. Field balancing in the real world

    Energy Technology Data Exchange (ETDEWEB)

    Bracher, B.

    1997-09-05

    Field balancing can achieve significant results when other problems are present in the frequency spectrum and multiple vibrations are evident in the waveform. Many references suggest eliminating other problems before attempting to balance. That`s great - if you can do it. There are valid reasons for this approach, and it would be much easier to balance machinery when other problems have been corrected. It is the theoretical ideal in field balancing. However, in the real world of machinery maintained for years by reacting to immediate problems, the classic vibration signature for unbalance is rarely seen. Maintenance personnel make most of their decisions with limited information. The decision to balance or not to balance is usually made the same way. This paper will demonstrate significant results of field balancing in the presence of multiple problems. By examining the data available and analyzing the probabilities, a reasonable chance for success can be assured.

  7. Ecological, biological balances and conservation

    International Nuclear Information System (INIS)

    The scientific work within the activity ''ecological/biological balances and conservation'' is summarised in this report. The aims of the activity during its existence between 1992 and 1994 have been to: (i) arrange a workshop and publish the presentations on the environmental aspects of energy forest cultivations, (ii) perform joint scientific work together with the activity group on ''biological disposal of wastewaters and sludges'', that is closely related to environmental problems, and (iii) produce ecological guidelines concerning energy forestry, suitable for advisers and farmers dealing with bioenergy problems. The most important results from the workshop were the environmental benefits from energy forestry when compared with intensive agriculture and forestry. Energy forestry has positive influence on the carbon balances, nutrient recycling, and soil sustainability. The effects are also positive on the natural flora and fauna, which in most cases are enriched when compared with agricultural crops. From the joint efforts of the two activities the main result was a study tour, conference and workshop, concentrating on biological purification systems. The most promising system seems to be the vegetation filters of short rotation coppice. The report on ecological guidelines contains a number of ideas and recommendations for establishment, management, and harvesting of energy forests in an environmentally acceptable way. It also gives advice on how to locate the stands to minimise the risk of nutrient leakage from arable land. (Author)

  8. Differential force balances during levitation

    Science.gov (United States)

    Todd, Paul

    The simplest arithmetic of inertial, buoyant, magnetic and electrokinetic levitation is explored in the context of a model living system with “acceleration-sensitive structures” in which motion, if allowed, produces a biological effect. The simple model is a finite-sized object enclosed within another finite-sized object suspended in an outer fluid (liquid or vapor) medium. The inner object has density and electrical and magnetic properties quantitatively different from those of the outer object and the medium. In inertial levitation (“weightlessness”) inertial accelerations are balanced, and the forces due to them are canceled in accordance with Newton’s third law. In the presence of inertial acceleration (gravity, centrifugal) motionlessness depends on a balance between the levitating force and the inertial force. If the inner and outer objects differ in density one or the other will be subjected to an unbalanced force when one object is levitated by any other force (buoyant, magnetic, electrokinetic). The requirements for motionlessness of the internal object in the presence of a levitating force are equality of density in the case of buoyant levitation, equality of magnetic susceptibility in the case of magnetic levitation, and equality of zeta potential and dielectric constant in the case of electrokinetic levitation. Examples of internal “acceleration-sensitive structures” are cellular organelles and the organs of advanced plants and animals. For these structures fundamental physical data are important in the interpretation of the effects of forces used for levitation.

  9. Mass balance assessment using GPS

    Science.gov (United States)

    Hulbe, Christina L.

    1993-01-01

    Mass balance is an integral part of any comprehensive glaciological investigation. Unfortunately, it is hard to determine at remote locations where there is no fixed reference. The Global Positioning System (GPS) offers a solution. Simultaneous GPS observations at a known location and the remote field site, processed differentially, will accurately position the camp site. From there, a monument planted in the firn atop the ice can also be accurately positioned. Change in the monument's vertical position is a direct indicator of ice thickness change. Because the monument is not connected to the ice, its motion is due to both mass balance change and to the settling of firn as it densifies into ice. Observations of relative position change between the monument and anchors at various depths within the firn are used to remove the settling effect. An experiment to test this method has begun at Byrd Station on the West Antarctic Ice Sheet and the first epoch of observations was made. Analysis indicates that positioning errors will be very small. It appears likely that the largest errors involved with this technique will arise from ancillary data needed to determine firn settling.

  10. Detection of the Water Reservoir in a Forming Planetary System

    CERN Document Server

    Hogerheijde, Michiel R; Brinch, Christian; Cleeves, L Ilsedore; Fogel, Jeffrey K J; Blake, Geoffrey A; Dominik, Carsten; Lis, Dariusz C; Melnick, Gary; Neufeld, David; Panic, Olja; Pearson, John C; Kristensen, Lars; Yildiz, Umut A; van Dishoeck, Ewine F

    2011-01-01

    Icy bodies may have delivered the oceans to the early Earth, yet little is known about water in the ice-dominated regions of extra-solar planet-forming disks. The Heterodyne Instrument for the Far-Infrared on-board the Herschel Space Observatory has detected emission from both spin isomers of cold water vapor from the disk around the young star TW Hydrae. This water vapor likely originates from ice-coated solids near the disk surface hinting at a water ice reservoir equivalent to several thousand Earth Oceans in mass. The water's ortho-to-para ratio falls well below that of Solar System comets, suggesting that comets contain heterogeneous ice mixtures collected across the entire solar nebula during the early stages of planetary birth.

  11. Cell phone based balance trainer

    Directory of Open Access Journals (Sweden)

    Lee Beom-Chan

    2012-02-01

    Full Text Available Abstract Background In their current laboratory-based form, existing vibrotactile sensory augmentation technologies that provide cues of body motion are impractical for home-based rehabilitation use due to their size, weight, complexity, calibration procedures, cost, and fragility. Methods We have designed and developed a cell phone based vibrotactile feedback system for potential use in balance rehabilitation training in clinical and home environments. It comprises an iPhone with an embedded tri-axial linear accelerometer, custom software to estimate body tilt, a "tactor bud" accessory that plugs into the headphone jack to provide vibrotactile cues of body tilt, and a battery. Five young healthy subjects (24 ± 2.8 yrs, 3 females and 2 males and four subjects with vestibular deficits (42.25 ± 13.5 yrs, 2 females and 2 males participated in a proof-of-concept study to evaluate the effectiveness of the system. Healthy subjects used the system with eyes closed during Romberg, semi-tandem Romberg, and tandem Romberg stances. Subjects with vestibular deficits used the system with both eyes-open and eyes-closed conditions during semi-tandem Romberg stance. Vibrotactile feedback was provided when the subject exceeded either an anterior-posterior (A/P or a medial-lateral (M/L body tilt threshold. Subjects were instructed to move away from the vibration. Results The system was capable of providing real-time vibrotactile cues that informed corrective postural responses. When feedback was available, both healthy subjects and those with vestibular deficits significantly reduced their A/P or M/L RMS sway (depending on the direction of feedback, had significantly smaller elliptical area fits to their sway trajectory, spent a significantly greater mean percentage time within the no feedback zone, and showed a significantly greater A/P or M/L mean power frequency. Conclusion The results suggest that the real-time feedback provided by this system can be used

  12. Sensitivity of Local Dynamic Stability of Over-Ground Walking to Balance Impairment Due to Galvanic Vestibular Stimulation.

    OpenAIRE

    Sloot, L.H.; Schooten, van, H.A.; Bruijn, S. M.; Kingma, H; Pijnappels, M.A.G.M.; Dieen, van, J.H.

    2011-01-01

    Impaired balance control during gait can be detected by local dynamic stability measures. For clinical applications, the use of a treadmill may be limiting. Therefore, the aim of this study was to test sensitivity of these stability measures collected during short episodes of over-ground walking by comparing normal to impaired balance control. Galvanic vestibular stimulation (GVS) was used to impair balance control in 12 healthy adults, while walking up and down a 10 m hallway. Trunk kinemati...

  13. Single Switched Capacitor Battery Balancing System Enhancements

    Directory of Open Access Journals (Sweden)

    Joeri van Mierlo

    2013-04-01

    Full Text Available Battery management systems (BMS are a key element in electric vehicle energy storage systems. The BMS performs several functions concerning to the battery system, its key task being balancing the battery cells. Battery cell unbalancing hampers electric vehicles’ performance, with differing individual cell voltages decreasing the battery pack capacity and cell lifetime, leading to the eventual failure of the total battery system. Quite a lot of cell balancing topologies have been proposed, such as shunt resistor, shuttling capacitor, inductor/transformer based and DC energy converters. The shuttling capacitor balancing systems in particular have not been subject to much research efforts however, due to their perceived low balancing speed and high cost. This paper tries to fill this gap by briefly discussing the shuttling capacitor cell balancing topologies, focusing on the single switched capacitor (SSC cell balancing and proposing a novel procedure to improve the SSC balancing system performance. This leads to a new control strategy for the SSC system that can decrease the balancing system size, cost, balancing time and that can improve the SSC balancing system efficiency.

  14. Balance and injury in elite Australian footballers.

    Science.gov (United States)

    Hrysomallis, C; McLaughlin, P; Goodman, C

    2007-10-01

    This project measured pre-season balance ability and determined its relationship to knee and ankle ligament injuries during the season for professional Australian footballers. The balance test involved the players stepping onto a foam balance mat on top of a force plate and maintaining single limb balance. Throughout the playing season, injuries were monitored. The results from two hundred and ten players participating in this project were analysed. During the 2003 season, 8 % (17 out of 210) sustained a knee ligament injury and 10 % (21 out of 210) sustained an ankle ligament injury. Multivariate analysis revealed that pre-season balance ability was a significant independent predictor of ankle ligament injury. Players with low balance ability had at least twice as many ankle ligaments injuries as those with average or good balance ability. Balance ability was not a significant predictor of knee ligament injuries. The height of the players was the only significant independent predictor of knee ligament injuries. Low pre-season balance ability was associated with an increased risk of ankle ligament injury. A modifiable injury risk factor has been identified. Research is now required to determine the optimal training regime to enhance balance ability and whether this translates to a reduction in the incidence of ankle injuries. PMID:17373597

  15. Energy-balance climate models

    Science.gov (United States)

    North, G. R.; Cahalan, R. F.; Coakley, J. A., Jr.

    1980-01-01

    An introductory survey of the global energy balance climate models is presented with an emphasis on analytical results. A sequence of increasingly complicated models involving ice cap and radiative feedback processes are solved and the solutions and parameter sensitivities are studied. The model parameterizations are examined critically in light of many current uncertainties. A simple seasonal model is used to study the effects of changes in orbital elements on the temperature field. A linear stability theorem and a complete nonlinear stability analysis for the models are developed. Analytical solutions are also obtained for the linearized models driven by stochastic forcing elements. In this context the relation between natural fluctuation statistics and climate sensitivity is stressed.

  16. A Generalized Detailed Balance Relation

    Science.gov (United States)

    Ruelle, David

    2016-08-01

    Given a system M in a thermal bath we obtain a generalized detailed balance relation for the ratio r=π _τ (K→ J)/π _τ (J→ K) of the transition probabilities M:J→ K and M:K→ J in time τ . We assume an active bath, containing solute molecules in metastable states. These molecules may react with M and the transition J→ K occurs through different channels α involving different reactions with the bath. We find that r=sum p^α r^α , where p^α is the probability that channel α occurs, and r^α depends on the amount of heat (more precisely enthalpy) released to the bath in channel α.

  17. Relevance of balance measurement tools and balance training for fall prevention in older adults

    Directory of Open Access Journals (Sweden)

    Majumi M. Noohu, MPTh

    2014-06-01

    Full Text Available Approximately one in three older people fall each year owing to gait/balance disorder/weakness, the second leading cause of falls in older adults. This review evaluates the capability of different balance measurement tools to predict falls in the elderly, which are used routinely for assessing balance impairment. Balance measurement tools reviewed are the Timed Up and Go test, Berg Balance Scale, Tinetti Performance Oriented Mobility Assessment, Functional Reach Test, Clinical Test of Sensory Integration for Balance, and the postural sway measurements or center of pressure. The effect of balance training on the postural control mechanism and its efficacy in fall prevention in older adults were also reviewed. The current evidence is not conclusive enough to favor existing balance measurement tools and balance training implemented for fall prevention in older adults.

  18. Milestones in gait, balance, and falling.

    Science.gov (United States)

    Nutt, John G; Horak, Fay B; Bloem, Bastiaan R

    2011-05-01

    Gait, balance, and falls have become increasingly common topics of published articles in the Movement Disorders journal since its launch in 1986. This growth represents an increasing awareness of the importance of mobility to patients' quality of life. New methods have become available that allow for accurate measurement of many aspects for gait and balance. This has led to new concepts of understanding gait and balance disorders. Neuroimaging has begun to reveal the neural circuitry underlying gait and balance. The physiology and pathophysiology of balance and gait are beginning to tease out the many processes involved in mobility and how they may be disrupted by disease processes. With these advances, the old therapeutic nihilism that characterized the clinician's approach to falls and gait disorders is disappearing, as innovative physiotherapy, exercise, drugs, and deep brain stimulation are being employed for gait and balance disorders. PMID:21626560

  19. Balance Systems and the Variational Bicomplex

    Science.gov (United States)

    Preston, Serge

    2011-07-01

    In this work we show that the systems of balance equations (balance systems) of continuum thermodynamics occupy a natural place in the variational bicomplex formalism. We apply the vertical homotopy decomposition to get a local splitting (in a convenient domain) of a general balance system as the sum of a Lagrangian part and a complemental ''pure non-Lagrangian'' balance system. In the case when derivatives of the dynamical fields do not enter the constitutive relations of the balance system, the ''pure non-Lagrangian'' systems coincide with the systems introduced by S. Godunov [Soviet Math. Dokl. 2 (1961), 947-948] and, later, asserted as the canonical hyperbolic form of balance systems in [Müller I., Ruggeri T., Rational extended thermodynamics, 2nd ed., Springer Tracts in Natural Philosophy, Vol. 37, Springer-Verlag, New York, 1998].

  20. Balance Systems and the Variational Bicomplex

    Directory of Open Access Journals (Sweden)

    Serge Preston

    2011-07-01

    Full Text Available In this work we show that the systems of balance equations (balance systems of continuum thermodynamics occupy a natural place in the variational bicomplex formalism. We apply the vertical homotopy decomposition to get a local splitting (in a convenient domain of a general balance system as the sum of a Lagrangian part and a complemental ''pure non-Lagrangian'' balance system. In the case when derivatives of the dynamical fields do not enter the constitutive relations of the balance system, the ''pure non-Lagrangian'' systems coincide with the systems introduced by S. Godunov [Soviet Math. Dokl. 2 (1961, 947-948] and, later, asserted as the canonical hyperbolic form of balance systems in [Müller I., Ruggeri T., Rational extended thermodynamics, 2nd ed., Springer Tracts in Natural Philosophy, Vol. 37, Springer-Verlag, New York, 1998].