WorldWideScience

Sample records for cross phase modulation

  1. Large conditional single-photon cross-phase modulation

    Science.gov (United States)

    Hosseini, Mahdi; Duan, Yiheng; Vuletić, Vladan

    2016-01-01

    Deterministic optical quantum logic requires a nonlinear quantum process that alters the phase of a quantum optical state by π through interaction with only one photon. Here, we demonstrate a large conditional cross-phase modulation between a signal field, stored inside an atomic quantum memory, and a control photon that traverses a high-finesse optical cavity containing the atomic memory. This approach avoids fundamental limitations associated with multimode effects for traveling optical photons. We measure a conditional cross-phase shift of π/6 (and up to π/3 by postselection on photons that remain in the system longer than average) between the retrieved signal and control photons, and confirm deterministic entanglement between the signal and control modes by extracting a positive concurrence. By upgrading to a state-of-the-art cavity, our system can reach a coherent phase shift of π at low loss, enabling deterministic and universal photonic quantum logic. PMID:27519798

  2. Terahertz cross-phase modulation of an optical mode

    DEFF Research Database (Denmark)

    Lavrinenko, Andrei; Novitsky, Andrey; Zalkovskij, Maksim

    2013-01-01

    We discuss an optical scheme which facilitates modulation of an optical waveguide mode by metallic-nanoslit-enhanced THz radiation. The waveguide mode acquires an additional phase shift due to THz nonlinearity with fields reachable in experiments.......We discuss an optical scheme which facilitates modulation of an optical waveguide mode by metallic-nanoslit-enhanced THz radiation. The waveguide mode acquires an additional phase shift due to THz nonlinearity with fields reachable in experiments....

  3. All-optical wavelength converter based on fiber cross-phase modulation and fiber Bragg grating

    Czech Academy of Sciences Publication Activity Database

    Honzátko, Pavel

    2010-01-01

    Roč. 283, č. 9 (2010), s. 1744-1749 ISSN 0030-4018 R&D Projects: GA AV ČR 1ET300670502 Institutional research plan: CEZ:AV0Z20670512 Keywords : Wavelength conversion * Fiber cross phase modulation * Fiber Bragg grating Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.517, year: 2010

  4. Development of Femtosecond Stimulated Raman Spectroscopy: Stimulated Raman Gain via Elimination of Cross Phase Modulation

    International Nuclear Information System (INIS)

    Jin, Seung Min; Lee, Young Jong; Yu, Jong Wan; Kim, Seong Keun

    2004-01-01

    We have developed a new femtosecond probe technique by using stimulated Raman spectroscopy. The cross phase modulation in femtosecond time scale associated with off-resonant interaction was shown to be eliminated by integrating the transient gain/loss signal over the time delay between the Raman pump pulse and the continuum pulse. The stimulated Raman gain of neat cyclohexane was obtained to demonstrate the feasibility of the technique. Spectral and temporal widths of stimulated Raman spectra were controlled by using a narrow band pass filter. Femtosecond stimulated Raman spectroscopy was proposed as a highly useful probe in time-resolved vibrational spectroscopy

  5. All-Optical 40 Gbit/s Regenerative Wavelength Conversion Based on Cross-Phase Modulation in a Silicon Nanowire

    DEFF Research Database (Denmark)

    Jensen, Asger Sellerup; Hu, Hao; Ji, Hua

    2013-01-01

    We successfully demonstrate all-optical regeneration of a 40 Gbit/s signal based on cross-phase modulation in a silicon nanowire. Bit-error-rate measurements show an average of 1.7dB improvement in receiver sensitivity after the regeneration.......We successfully demonstrate all-optical regeneration of a 40 Gbit/s signal based on cross-phase modulation in a silicon nanowire. Bit-error-rate measurements show an average of 1.7dB improvement in receiver sensitivity after the regeneration....

  6. Optical wavelength conversion by cross-phase modulation of data signals up to 640 Gb/s

    DEFF Research Database (Denmark)

    Galili, Michael; Oxenløwe, Leif Katsuo; Mulvad, Hans Christian Hansen

    2008-01-01

    In this paper, all-optical wavelength conversion by cross-phase modulation in a highly nonlinear fiber is investigated. Regenerative properties of the wavelength converter are demonstrated, and the effect of adding Raman gain to enhance the performance of the wavelength converter is shown. The wa....... The wavelength conversion scheme is demonstrated at the record-high bit rate of 640 Gb/s.......In this paper, all-optical wavelength conversion by cross-phase modulation in a highly nonlinear fiber is investigated. Regenerative properties of the wavelength converter are demonstrated, and the effect of adding Raman gain to enhance the performance of the wavelength converter is shown...

  7. Deterministic reshaping of single-photon spectra using cross-phase modulation.

    Science.gov (United States)

    Matsuda, Nobuyuki

    2016-03-01

    The frequency conversion of light has proved to be a crucial technology for communication, spectroscopy, imaging, and signal processing. In the quantum regime, it also offers great potential for realizing quantum networks incorporating disparate physical systems and quantum-enhanced information processing over a large computational space. The frequency conversion of quantum light, such as single photons, has been extensively investigated for the last two decades using all-optical frequency mixing, with the ultimate goal of realizing lossless and noiseless conversion. I demonstrate another route to this target using frequency conversion induced by cross-phase modulation in a dispersion-managed photonic crystal fiber. Owing to the deterministic and all-optical nature of the process, the lossless and low-noise spectral reshaping of a single-photon wave packet in the telecommunication band has been readily achieved with a modulation bandwidth as large as 0.4 THz. I further demonstrate that the scheme is applicable to manipulations of a nonclassical frequency correlation, wave packet interference, and entanglement between two photons. This approach presents a new coherent frequency interface for photons for quantum information processing.

  8. Measurement of pulse amplitude and phase using cross-phase modulation in microstructure fiber

    Czech Academy of Sciences Publication Activity Database

    Honzátko, Pavel; Kaňka, Jiří; Vraný, Boleslav

    2005-01-01

    Roč. 30, č. 14 (2005), s. 1821-1823 ISSN 0146-9592 R&D Projects: GA ČR(CZ) GA102/05/0995; GA AV ČR(CZ) IAA1067301 Institutional research plan: CEZ:AV0Z20670512 Keywords : pulse measurement * phase measurement * nonlinear optics Subject RIV: BH - Optics, Masers, Lasers Impact factor: 3.599, year: 2005

  9. Integrable high order UWB pulse photonic generator based on cross phase modulation in a SOA-MZI.

    Science.gov (United States)

    Moreno, Vanessa; Rius, Manuel; Mora, José; Muriel, Miguel A; Capmany, José

    2013-09-23

    We propose and experimentally demonstrate a potentially integrable optical scheme to generate high order UWB pulses. The technique is based on exploiting the cross phase modulation generated in an InGaAsP Mach-Zehnder interferometer containing integrated semiconductor optical amplifiers, and is also adaptable to different pulse modulation formats through an optical processing unit which allows to control of the amplitude, polarity and time delay of the generated taps.

  10. EIT-based all-optical switching and cross-phase modulation under the influence of four-wave mixing.

    Science.gov (United States)

    Lee, Meng-Jung; Chen, Yi-Hsin; Wang, I-Chung; Yu, Ite A

    2012-05-07

    All-optical switching (AOS) or cross-phase modulation (XPM) based on the effect of electromagnetically induced transparency (EIT) makes one photon switched or phase-modulated by another possible. The existence of four-wave mixing (FWM) process greatly diminishes the switching or phase-modulation efficiency and hinders the single-photon operation. We proposed and experimentally demonstrated an idea that with an optimum detuning the EIT-based AOS can be completely intact even under the influence of FWM. The results of the work can be directly applied to the EIT-based XPM. Our work makes the AOS and XPM schemes more flexible and the single-photon operation possible in FWM-allowed systems.

  11. Crossed modules of racks

    OpenAIRE

    Crans, Alissa S.; Wagemann, Friedrich

    2014-01-01

    We generalize the notion of a crossed module of groups to that of a crossed module of racks. We investigate the relation to categorified racks, namely strict 2-racks, and trunk-like objects in the category of racks, generalizing the relation between crossed modules of groups and strict 2-groups. Then we explore topological applications. We show that by applying the rack-space functor, a crossed module of racks gives rise to a covering. Our main result shows how the fundamental racks associate...

  12. All-optical short pulse translation through cross-phase modulation in a VO₂ thin film.

    Science.gov (United States)

    Fardad, Shima; Das, Susobhan; Salandrino, Alessandro; Breckenfeld, Eric; Kim, Heungsoo; Wu, Judy; Hui, Rongqing

    2016-01-15

    VO2 is a promising material for reconfigurable photonic devices due to the ultrafast changes in electronic and optical properties associated with its dielectric-to-metal phase transition. Based on a fiber-optic, pump-probe setup at 1550 nm wavelength window, and by varying the pump-pulse duration, we show that the material phase transition is primarily caused by the pump-pulse energy. For the first time, we demonstrate that the instantaneous optical phase modulation of probe during pump leading edge can be utilized to create short optical pulses at probe wavelength, through optical frequency discrimination. This circumvents the impact of long recovery time well known for the phase transition of VO2.

  13. Enhanced Cross-Phase Modulation Based on a Double Electromagnetically Induced Transparency in a Four-Level Tripod Atomic System

    International Nuclear Information System (INIS)

    Li Shujing; Yang Xudong; Cao Xuemin; Zhang Chunhong; Xie Changde; Wang Hai

    2008-01-01

    We report experimental observations on the simultaneous electromagnetically induced transparency (EIT) effects for probe and trigger fields (double EIT) as well as the enhanced cross-phase modulation (XPM) between the two fields in a four-level tripod EIT system of the D1 line of 87 Rb atoms. The XPM coefficients (larger than 2x10 -5 cm 2 /W) and the accompanying transmissions (higher than 60%) are measured at a slight detuning of the probe field from the exact EIT-resonance condition. The system and enhanced cross-Kerr nonlinearities presented here can be applied to quantum information processes

  14. Simultaneous all-optical demultiplexing and regeneration based on self-phase and cross-phase modulation in a dispersion shifted fiber

    DEFF Research Database (Denmark)

    Yu, Jianjun; Jeppesen, Palle

    2001-01-01

    Simultaneous demultiplexing and regeneration of 40-Gb/s optical time division multiplexed (OTDM) signal based on self-phase and cross-phase modulation in a dispersion shifted fiber is numerically and experimentally investigated. The optimal walkoff time between the control pulse and OTDM signal...... is obtained by numerical simulation. Our experiment also shows that it is an effective method for realizing simultaneous demultiplexing and regeneration when used in the middle of a system or in the receiver with a proper walkoff time....

  15. INFLUENCE OF POLARIZATION MODE DISPERSION ON THE EFFECT OF CROSS-PHASE MODULATION IN INTENSITY MODULATION-DIRECT DETECTION WDM TRANSMISSION SYSTEM

    Directory of Open Access Journals (Sweden)

    M S Islam

    2010-03-01

    Full Text Available Cross-phase modulation (XPM changes the state-of-polarization (SOP of the channels through nonlinear polarization rotation and induces nonlinear time dependent phase shift for polarization components that leads to amplitude modulation of the propagating waves in a wavelength division multiplexing (WDM system. Due to the presence of birefringence, the angle between the SOP changes randomly and as a result polarization mode dispersion (PMD causes XPM modulation amplitude fluctuation random in the perturbed channel. In this paper we analytically determine the probability density function of the random angle between the SOP of pump and probe, and evaluate the impact of polarization mode dispersion on XPM in terms of bit error rate, channel spacing etc for a two channel intensity modulation-direct detection WDM system at 10 Gb/s. It is found that the XPM induced crosstalk is polarization independent for channel spacing greater than 3 nm or PMD coefficient larger than 2 ps/√km. We also investigate the dependence of SOP variance on PMD coefficient and channel spacing.

  16. Validation of Friction Models in MARS-MultiD Module with Two-Phase Cross Flow Experiment

    International Nuclear Information System (INIS)

    Choi, Chi-Jin; Yang, Jin-Hwa; Cho, Hyoung-Kyu; Park, Goon-Cher; Euh, Dong-Jin

    2015-01-01

    In the downcomer of Advanced Power Reactor 1400 (APR1400) which has direct vessel injection (DVI) lines as an emergency core cooling system, multidimensional two-phase flow may occur due to the Loss-of-Coolant-Accident (LOCA). The accurate prediction about that is high relevance to evaluation of the integrity of the reactor core. For this reason, Yang performed an experiment that was to investigate the two-dimensional film flow which simulated the two-phase cross flow in the upper downcomer, and obtained the local liquid film velocity and thickness data. From these data, it could be possible to validate the multidimensional modules of system analysis codes. In this study, MARS-MultiD was used to simulate the Yang's experiment, and obtained the local variables. Then, the friction models used in MARS-MultiD were validated by comparing the two-phase flow experimental results with the calculated local variables. In this study, the two-phase cross flow experiment was modeled by the MARS-MultiD. Compared with the experimental results, the calculated results by the code properly presented mass conservation which could be known from the relation between the liquid film velocity and thickness at the same flow rate. The magnitude and direction of the liquid film, however, did not follow well with experimental results. According to the results of Case-2, wall friction should be increased, and interfacial friction should be decreased in MARS-MultiD. These results show that it is needed to modify the friction models in the MARS-MultiD to simulate the two-phase cross flow

  17. Cross-phase modulation instability in optical fibres with exponential saturable nonlinearity and high-order dispersion

    International Nuclear Information System (INIS)

    Xian-Qiong, Zhong; An-Ping, Xiang

    2010-01-01

    Utilizing the linear-stability analysis, this paper analytically investigates and calculates the condition and gain spectra of cross-phase modulation instability in optical fibres in the case of exponential saturable nonlinearity and high-order dispersion. The results show that, the modulation instability characteristics here are similar to those of conventional saturable nonlinearity and Kerr nonlinearity. That is to say, when the fourth-order dispersion has the same sign as that of the second-order one, a new gain spectral region called the second one which is far away from the zero point may appear. The existence of the exponential saturable nonlinearity will make the spectral width as well as the peak gain of every spectral region increase with the input powers before decrease. Namely, for every spectral regime, this may lead to a unique value of peak gain and spectral width for two different input powers. In comparison with the case of conventional saturable nonlinearity, however, when the other parameters are the same, the variations of the spectral width and the peak gain with the input powers will be faster in case of exponential saturable nonlinearity. (classical areas of phenomenology)

  18. Cross polarization with phase and amplitude modulation of radio frequency fields in NMR-experiments with sample rotation at magic angle

    International Nuclear Information System (INIS)

    Dvinskij, S.V.; Chizhik, V.I.

    2006-01-01

    One analyzes cross polarization of nuclei within a rotating system of coordinates as applied to the NMR-experiments with a specimen rotation under the magic angle. One worded a concept of simultaneous phase and amplitude modulation according to which the Hamiltonian form of the restored dipole interaction persisted if inversion of difference of radiofrequency field amplitudes occurred simultaneously with phase inversion. One presents a theoretical substantiation in terms of the average Hamiltonian theory. The concept is demonstrated both experimentally and by means of numerical analysis for a number of special cases. Phase periodic inversion in cross polarized experiments is shown to result into practically important advantage of suppression of interactions of chemical shift and influence of effects of coarse adjustment of radiofrequency field parameters [ru

  19. Graphene based terahertz phase modulators

    Science.gov (United States)

    Kakenov, N.; Ergoktas, M. S.; Balci, O.; Kocabas, C.

    2018-07-01

    Electrical control of amplitude and phase of terahertz radiation (THz) is the key technological challenge for high resolution and noninvasive THz imaging. The lack of active materials and devices hinders the realization of these imaging systems. Here, we demonstrate an efficient terahertz phase and amplitude modulation using electrically tunable graphene devices. Our device structure consists of electrolyte-gated graphene placed at quarter wavelength distance from a reflecting metallic surface. In this geometry, graphene operates as a tunable impedance surface which yields electrically controlled reflection phase. Terahertz time domain reflection spectroscopy reveals the voltage controlled phase modulation of π and the reflection modulation of 50 dB. To show the promises of our approach, we demonstrate a multipixel phase modulator array which operates as a gradient impedance surface.

  20. Cross-cultural development of a quality-of-life measure for patients with melanoma: phase 3 testing of an EORTC Melanoma Module.

    Science.gov (United States)

    Winstanley, Julie B; Young, Teresa E; Boyle, Frances M; Bergenmar, Mia; Bottomley, Andrew; Burmeister, Bryan; Campana, Luca G; Garioch, Jennifer J; King, Madeleine; Nikolic, Dejan V; van de Poll-Franse, Lonneke V; Saw, Robyn; Thompson, John F; White, Edward G

    2015-02-01

    Melanoma is an increasingly common skin cancer worldwide. Recent treatment advances have provided patients and healthcare professionals (HCPs) with choices where quality of life (QoL) and toxicity are important considerations. A melanoma-specific QoL questionnaire is being developed in a cross-cultural setting using a four phase process developed by the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Group. In phase 1, a literature search identified a list of pertinent QoL issues; this was shown to HCPs and patients in eight countries and rated for importance and relevance. Questions were constructed for the highest-rated issues (phase 2) and piloted in another patient sample (phase 3). Using EORTC Quality of Life Group criteria and sequential use of factor and Rasch analysis, scales were hypothesized for field testing (phase 4). Seven QoL domains (disease symptoms, treatment issues, financial issues, access/quality of information, satisfaction with care, psychosocial issues and support), comprising 73 QoL issues, were rated by 46 HCPs and 78 patients. Fifty-six issues were rephrased as questions and piloted with 132 patients. A 38-item questionnaire (QLQ-MEL38) is available for field testing in conjunction with the EORTC QLQ-C30. This study has shown that melanoma patients have important QoL issues that have been incorporated into a new cross-culturally validated instrument. Future testing of this EORTC module is planned and will be an important step forward in providing reliable QoL data to aid future decision-making in the management and clinical trials of this complex group of patients.

  1. Optimization of genetic algorithm for reconstruction of cross-phase modulation frequency-resolved optical gating data

    Czech Academy of Sciences Publication Activity Database

    Vraný, Boleslav; Honzátko, Pavel; Kaňka, Jiří

    2011-01-01

    Roč. 24, č. 5 (2011), 448-456 ISSN 0894-3370 R&D Projects: GA MŠk OE08021 Institutional research plan: CEZ:AV0Z20670512 Keywords : frequency resolved optical gating, FROG * amplitude and phase retrieval * genetic algorithm, GA Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.600, year: 2011

  2. Wavelength conversion, time demultiplexing and multicasting based on cross-phase modulation and four-wave mixing in dispersion-flattened highly nonlinear photonic crystal fiber

    International Nuclear Information System (INIS)

    Hui, Zhan-Qiang; Zhang, Jian-Guo

    2012-01-01

    We propose the use of cross-phase modulation (XPM) and four-wave mixing (FWM) in dispersion-flattened highly nonlinear photonic crystal fibers (HNL-PCFs) to implement the functionalities of wavelength conversion, simultaneous time demultiplexing and wavelength multicasting in optical time-division multiplexing (OTDM) systems. The experiments on wavelength conversion at 80 Gbit s −1 and OTDM demultiplexing from 80 to 10 Gbit s −1 with wavelength multicasting of two channels are successfully demonstrated to validate the proposed scheme, which are carried out by using two segments of dispersion-flattened HNL-PCFs with lengths of 100 and 50 m, respectively. Moreover, the bit error rate (BER) performance is also measured. The results show that our designed system can achieve a power penalty of less than 4.6 dB for two multicasting channels with a 24 nm wavelength span at the BER of 10 −9 when compared with the 10 Gbit/s back-to-back measurement. The proposed system is transparent to bit rate since only an ultrafast third-order nonlinear effect is used. The resulting configuration is compact, robust and reliable, benefiting from the use of dispersion-flattened HNL-PCFs with short lengths. This also makes the proposed system more flexible in the operational wavelengths than those based on dispersion-shifted fibers and traditional highly nonlinear fibers. (paper)

  3. Widely tunable broadband deep-ultraviolet to visible wavelength generation by the cross phase modulation in a hollow-core photonic crystal fiber cladding

    International Nuclear Information System (INIS)

    Yuan, J H; Sang, X Z; Wu, Q; Yu, C X; Shen, X W; Wang, K R; Yan, B B; Teng, Y L; Farrell, G; Zhou, G Y; Xia, C M; Han, Y; Li, S G; Hou, L T

    2013-01-01

    The deep-ultraviolet (UV) to visible wavelengths are efficiently generated for the first time by the cross phase modulation (XPM) between the red-shifted solitons and the blue-shifted dispersive waves (DWs) in the fundamental guided mode of the multi-knots of a hollow-core photonic crystal fiber cladding (HC-PCFC). When the femtosecond pulses with a wavelength of 850 nm and average power of 300 mW are coupled into the knots 1–3, the conversion efficiency η uv−v of 11% and bandwidth B uv−v of 100 nm in the deep-UV region are experimentally obtained. The multi-milliwatt ultrashort pulses are tunable over the deep-UV (below 200 nm) to visible spectral region by adjusting the wavelengths of the pump pulses in different knots. It is expected that these widely tunable broadband ultrashort deep-UV–visible pulse sources could have important applications in ultrafast photonics, femtochemisty, photobiology, and UV–visible resonant Raman scattering. (letter)

  4. Cavity Voltage Phase Modulation MD

    CERN Document Server

    Mastoridis, Themistoklis; Molendijk, John; Timko, Helga; CERN. Geneva. ATS Department

    2016-01-01

    The LHC RF/LLRF system is currently configured for extremely stable RF voltage to minimize transient beam loading effects. The present scheme cannot be extended beyond nominal beam current since the demanded power would exceed the peak klystron power and lead to saturation. A new scheme has therefore been proposed: for beam currents above nominal (and possibly earlier), the cavity phase modulation by the beam will not be corrected (transient beam loading), but the strong RF feedback and One-Turn Delay feedback will still be active for loop and beam stability in physics. To achieve this, the voltage set point will be adapted for each bunch. The goal of this MD was to test a new algorithm that would adjust the voltage set point to achieve the cavity phase modulation that would minimize klystron forward power.

  5. Frequency-Diversity Reception for Phase Modulation

    Science.gov (United States)

    Brockman, M. H.

    1984-01-01

    Signal-to-noise ratio improved. System receives phase modulation transmitted simultaneously on different carrier frequencies. Used for carriers received through different antennas or through same antenna.

  6. Mutually-modulated cross-gain modulation and slow light

    International Nuclear Information System (INIS)

    Sternklar, Shmuel; Sarid, Eyal; Wart, Maxim; Granot, Er'el

    2010-01-01

    The interaction of pump and Stokes light in a Brillouin medium, where both beams are modulated, can be utilized for controlling the group velocity of the amplified Stokes (or depleted pump). The dependence of the group velocity for this mutually-modulated cross-gain modulation (MMXGM) technique on the Brillouin gain parameter is studied. A sharp transition to slow light occurs in the G 1 α/β≈1 regime, where G 1 is the Brillouin gain parameter, and α and β are the pump and Stokes modulation indices, respectively. A comparison of MMXGM slow light to the Brillouin dispersion-based slow-light technique reveals the fundamental differences between them. The formation of higher harmonics of the modulation frequency is also discussed. The theoretical predictions are experimentally corroborated and potential applications in fiber-based sensing and interferometry are discussed

  7. Computing optimal interfacial structure of modulated phases

    OpenAIRE

    Xu, Jie; Wang, Chu; Shi, An-Chang; Zhang, Pingwen

    2016-01-01

    We propose a general framework of computing interfacial structures between two modulated phases. Specifically we propose to use a computational box consisting of two half spaces, each occupied by a modulated phase with given position and orientation. The boundary conditions and basis functions are chosen to be commensurate with the bulk structures. It is observed that the ordered nature of modulated structures stabilizes the interface, which enables us to obtain optimal interfacial structures...

  8. Polarization-insensitive all-optical dual pump-phase transmultiplexing from 2 x 10-GBd OOKs to 10-GBd RZ-QPSK using cross-phase modulation in a passive nonlinear birefringent photonic crystal fiber

    Science.gov (United States)

    Mahmood, Tanvir

    Considering the network size, bit rate, spectral and channel capacity limitations, different modulation formats may be selectively used in future optical networks. Although the traditional metropolitan area networks (MANs) still uses the non-return-to-zero on-off keying (NRZ-OOK) modulation format due to its technical simplicity and therefore low cost, QPSK format is more advantageous in spectrally efficient long-haul fiber optic transmission systems because of its constant power envelope, and robustness to various transmission impairments. Consequently, an important problem may arise, in particular how to route the OOK-data streams from MANs to long-haul backbone networks when the state of polarization (SOP) of the remotely generated OOK is unpredictable. Hence, the focus of this dissertation was to investigate a polarization insensitive (PI) all-optical nonlinear optical signal processing (NOSP) method that can be implemented at the network cross-connect (X-connect) to transfer data from a remotely and a locally generated OOK data simultaneously to more effectual QPSK format for long-haul transmission. By utilizing cross-phase modulation (XPM) and inherent birefringence of the device, the work demonstrated, for the first time, PI all-optical data transfer utilizing dual pump-phase transmultiplexing (DPTM) from 2 x 10-GBd OOKs to 10-GBd RZ-QPSK in a passive nonlinear birefringent photonic crystal fiber (PCF). Polarization insensitivity was achieved by scrambling the SOP of the remotely generated OOK pump and launching the locally generated OOK pump and the probe off-axis. To mitigate polarization induced power fluctuations and detrimental effects due to nearby partially degenerate and non-degenerate four wave mixings, an optimum pump-probe detuning was also utilized. The PI DPTM RZ-QPSK demonstrated a pre-amplified receiver sensitivity penalty < 5.5 dB at 10--9 bit-error-rate (BER), relative to relative to the FPGA-precoded RZ-DQPSK baseline in ASE

  9. Components of cross-frequency modulation in health and disease

    Directory of Open Access Journals (Sweden)

    Elena A Allen

    2011-07-01

    Full Text Available The cognitive deficits associated with schizophrenia are commonly believed to arise from the abnormal temporal integration of information, however a quantitative approach to assess network coordination is lacking. Here, we propose to use cross-frequency modulation, the dependence of local high-frequency activity on the phase of widespread low-frequency oscillations, as an indicator of network coordination and functional integration. In an exploratory analysis based on pre-existing data, we measured cross-frequency modulation from multi-channel EEG recordings acquired while schizophrenia patients (n = 47 and healthy controls (n = 130 performed an auditory oddball task. Novel application of independent component analysis (ICA to modulation data delineated components with specific spatial and spectral profiles, the weights of which showed co-variation with diagnosis. Global cross-frequency modulation was significantly greater in healthy controls (F1,175=9.25, P<0.005, while modulation at fronto-temporal electrodes was greater in patients (F1,175 =17.5, P<0.0001. We further found that the weights of schizophrenia-relevant components were associated with genetic polymorphisms at previously identified risk loci. Global cross-frequency modulation decreased with copies of 957C allele in the gene for the dopamine D2 receptor (r = −0.20, P < 0.01 across all subjects. Additionally, greater ‘aberrant’ fronto-temporal modulation in schizophrenia patients was correlated with several polymorphisms in the gene for the α2-subunit of the GABAA receptor (GABRA2 as well as the total number of risk alleles in GABRA2 (r = 0.45, P < 0.01. Overall, our results indicate great promise for this approach in establishing patterns of cross-frequency modulation in health and disease and elucidating the roles of oscillatory interactions in functional connectivity.

  10. Towards a Unified Understanding of Event-Related Changes in the EEG: The Firefly Model of Synchronization through Cross-Frequency Phase Modulation

    Science.gov (United States)

    Burgess, Adrian P.

    2012-01-01

    Although event-related potentials (ERPs) are widely used to study sensory, perceptual and cognitive processes, it remains unknown whether they are phase-locked signals superimposed upon the ongoing electroencephalogram (EEG) or result from phase-alignment of the EEG. Previous attempts to discriminate between these hypotheses have been unsuccessful but here a new test is presented based on the prediction that ERPs generated by phase-alignment will be associated with event-related changes in frequency whereas evoked-ERPs will not. Using empirical mode decomposition (EMD), which allows measurement of narrow-band changes in the EEG without predefining frequency bands, evidence was found for transient frequency slowing in recognition memory ERPs but not in simulated data derived from the evoked model. Furthermore, the timing of phase-alignment was frequency dependent with the earliest alignment occurring at high frequencies. Based on these findings, the Firefly model was developed, which proposes that both evoked and induced power changes derive from frequency-dependent phase-alignment of the ongoing EEG. Simulated data derived from the Firefly model provided a close match with empirical data and the model was able to account for i) the shape and timing of ERPs at different scalp sites, ii) the event-related desynchronization in alpha and synchronization in theta, and iii) changes in the power density spectrum from the pre-stimulus baseline to the post-stimulus period. The Firefly Model, therefore, provides not only a unifying account of event-related changes in the EEG but also a possible mechanism for cross-frequency information processing. PMID:23049827

  11. Phase ramping and modulation of reflectometer signals

    International Nuclear Information System (INIS)

    Conway, G.D.; Bartlett, D.V.; Stoff, P.E.

    1999-01-01

    The phase and amplitude signals of JET heterodyne reflectometers show varying levels of high frequency turbulence superimposed on a slow changing mean. The phase signal also shows multi-radian (> 1 fringe) variations with two quite different time scales (2-10 ms and sub-ms). In both cases the mean reflected power, together with turbulent phase and amplitude fluctuation levels, are modulated synchronously with the are modulated synchronously with the phase fringes. The slow fringes appear to result radial movement of the cutoff layer with the amplitude modulation possibly due to multiple reflection between plasma and wall. The fast fringes occur in intermittent bursts and appear to be phase runaway resulting from antenna misalignment. Using a 2-D physical optics simulation code it is possible to replicate the fast bursts of phase runaway from steady-state turbulence and misaligned antennas. This offers a possible alternative explanation for some of the observations of bursting turbulence seen in reflectometer signals. (authors)

  12. Phase-Modulated Optical Communication Systems

    CERN Document Server

    Ho, Keang-Po

    2005-01-01

    Fiber-optic communication systems have revolutionized our telecommunication infrastructures – currently, almost all telephone land-line, cellular, and internet communications must travel via some form of optical fibers. In these transmission systems, neither the phase nor frequency of the optical signal carries information – only the intensity of the signal is used. To transmit more information in a single optical carrier, the phase of the optical carrier must be explored. As a result, there is renewed interest in phase-modulated optical communications, mainly in direct-detection DPSK signals for long-haul optical communication systems. When optical amplifiers are used to maintain certain signal level among the fiber link, the system is limited by amplifier noises and fiber nonlinearities. Phase-Modulated Optical Communication Systems surveys this newly popular area, covering the following topics: The transmitter and receiver for phase-modulated coherent lightwave systems Method for performance analysis o...

  13. Anomalous cross-modulation between microwave beams

    Science.gov (United States)

    Ranfagni, Anedio; Mugnai, Daniela; Petrucci, Andrea; Mignani, Roberto; Cacciari, Ilaria

    2018-06-01

    An anomalous effect in the near field of crossing microwave beams, which consists of an unexpected transfer of modulation from one beam to the other, has found a plausible interpretation within the framework of a locally broken Lorentz invariance. A theoretical approach of this kind deserves to be reconsidered also in the light of further experimental work, including a counter-check of the phenomenon.

  14. Geometric phase modulation for stellar interferometry

    International Nuclear Information System (INIS)

    Roy, M.; Boschung, B.; Tango, W.J.; Davis, J.

    2002-01-01

    Full text: In a long baseline optical interferometer, the fringe visibility is normally measured by modulation of the optical path difference between the two arms of the instruments. To obtain accurate measurements, the spectral bandwidth must be narrow, limiting the sensitivity of the technique. The application of geometric phase modulation technique to stellar interferometry has been proposed by Tango and Davis. Modulation of the geometric phase has the potential for improving the sensitivity of optical interferometers, and specially the Sydney University Stellar Interferometer (SUSI), by allowing broad band modulation of the light signals. This is because a modulator that changes the geometric phase of the signal is, in principle, achromatic. Another advantage of using such a phase modulator is that it can be placed in the common path traversed by the two orthogonally polarized beams emerging from the beam combiner in a stellar interferometer. Thus the optical components of the modulator do not have to be interferometric quality and could be relatively easily introduced into SUSI. We have investigated the proposed application in a laboratory-based experiment using a Mach-Zehnder interferometer with white-light source. This can be seen as a small model of an amplitude stellar interferometer where the light source takes the place of the distant star and two corner mirrors replaces the entrance pupils of the stellar interferometer

  15. Amplitude and phase modulation with waveguide optics

    International Nuclear Information System (INIS)

    Burkhart, S.C.; Wilcox, R.B.; Browning, D.; Penko, F.A.

    1996-01-01

    We have developed amplitude and phase modulation systems for glass lasers using integrated electro-optic modulators and solid state high-speed electronics. The present and future generation of lasers for Inertial Confinement Fusion require laser beams with complex temporal and phase shaping to compensate for laser gain saturation, mitigate parametric processes such as transverse stimulated Brillouin scattering in optics, and to provide specialized drive to the fusion targets. These functions can be performed using bulk optoelectronic modulators, however using high-speed electronics to drive low voltage integrated optical modulators has many practical advantages. In particular, we utilize microwave GaAs transistors to perform precision, 250 ps resolution temporal shaping. Optical bandwidth is generated using a microwave oscillator at 3 GHz amplified by a solid state amplifier. This drives an integrated electrooptic modulator to achieve laser bandwidths exceeding 30 GHz

  16. Modulational instability of nematic phase

    Indian Academy of Sciences (India)

    2014-02-08

    Feb 8, 2014 ... all phases show MI, but at the same time it has also been found that for antiferro- magnetic phase, MI depends on the relative .... with wave functions, time and spatial coordinates are measured in the units of. (¯h/2mωz)−3/2, ω−1 ... The manipulation of the resulting matrix gives eigenvalues. From the form of ...

  17. Symmetry, phase modulation and nonlinear waves

    CERN Document Server

    Bridges, Thomas J

    2017-01-01

    Nonlinear waves are pervasive in nature, but are often elusive when they are modelled and analysed. This book develops a natural approach to the problem based on phase modulation. It is both an elaboration of the use of phase modulation for the study of nonlinear waves and a compendium of background results in mathematics, such as Hamiltonian systems, symplectic geometry, conservation laws, Noether theory, Lagrangian field theory and analysis, all of which combine to generate the new theory of phase modulation. While the build-up of theory can be intensive, the resulting emergent partial differential equations are relatively simple. A key outcome of the theory is that the coefficients in the emergent modulation equations are universal and easy to calculate. This book gives several examples of the implications in the theory of fluid mechanics and points to a wide range of new applications.

  18. Phase multistability of self-modulated oscillations

    DEFF Research Database (Denmark)

    Sosnovtseva, Olga; Postnov, D.E.; Nekrasov, A.M.

    2002-01-01

    The paper examines the type of multistability that one can observe in the synchronization of two oscillators when the systems individually display self-modulation or other types of multicrest wave forms. The investigation is based on a phase reduction method and on the calculation of phase maps...... nonlinearity and a biologically motivated model of nephron autoregulation are presented....

  19. Phase ramping and modulation of reflectometer signals

    International Nuclear Information System (INIS)

    Conway, G.; Bartlett, D.; Stott, P.

    1999-06-01

    The phase and amplitude signals of JET heterodyne reflectometers show varying levels of high frequency turbulence superimposed on a slow changing mean. The phase signal also shows multi-radian (>1 fringe) variations with two quite different time scales (2-10ms and sub-ms). In both cases the mean reflected power, together with turbulent phase and amplitude fluctuation levels, are modulated synchronously with the phase fringes. The slow fringes appear to result from radial movement of the cutoff layer with the amplitude modulation possibly due to multiple reflection between plasma and wall. The fast fringes occur in intermittent bursts and appear to be phase runaway resulting from antenna misalignment. Using a 2D physical optics simulation code it is possible to replicate the fast bursts of phase runaway from steady-state turbulence and misaligned antennas. This offers a possible alternative explanation for some of the observations of bursting turbulence seen in reflectometer signals. (author)

  20. Crossed Module Bundle Gerbes; Classification, String Group and Differential Geometry

    OpenAIRE

    Jurco, Branislav

    2005-01-01

    We discuss nonabelian bundle gerbes and their differential geometry using simplicial methods. Associated to any crossed module there is a simplicial group NC, the nerve of the 1-category defined by the crossed module and its geometric realization |NC|. Equivalence classes of principal bundles with structure group |NC| are shown to be one-to-one with stable equivalence classes of what we call crossed module gerbes bundle gerbes. We can also associate to a crossed module a 2-category C'. Then t...

  1. SSD with generalized phase modulation

    International Nuclear Information System (INIS)

    Rothenberg, J.

    1996-01-01

    Smoothing by spectral dispersion (SSD) with standard frequency modulation (FM), although simple to implement, has the disadvantage that low spatial frequencies present in the spectrum of the target illumination are not smoothed as effectively as with a more general smoothing method (eg, induced spatial incoherence method). The reduced smoothing performance of standard FM-SSD can result in spectral power of the speckle noise at these low spatial frequencies as much as one order of magnitude larger than that achieved with a more general method. In fact, at small integration times FM-SSD has no smoothing effect at all for a broad band of low spatial frequencies. This effect may have important implications for both direct and indirect drive ICF

  2. Chromaticity tracking using a phase modulation technique

    International Nuclear Information System (INIS)

    Tan, C.Y.; Fermilab

    2007-01-01

    In the classical chromaticity measurement technique, chromaticity is measured by measuring the change in betatron tune as the RF frequency is varied. This paper will describe a novel way of measuring chromaticity: we will phase modulate the RF with a known sine wave and then phase demodulate the betatron frequency. The result is a line in Fourier space which corresponds to the frequency of our sine wave modulation. The peak of this sine wave is proportional to chromaticity. For this technique to work, a tune tracker PLL system is required because it supplies the betatron carrier frequency. This method has been tested in the Tevatron and we will show the results here

  3. Phase-Modulation Laser Interference Microscopy

    DEFF Research Database (Denmark)

    Brazhe, Alexey; Brazhe, Nadezda; Maximov, G. V.

    2008-01-01

    We describe how phase-modulation laser interference microscopy and wavelet analysis can be applied to noninvasive nonstained visualization and study of the structural and dynamical properties of living cells. We show how phase images of erythrocytes can reveal the difference between various...... erythrocyte forms and stages of hemolysis and how phase images of neurons reveal their complex intracellular structure. Temporal variations of the refractive index are analyzed to detect cellular rhythmic activity on different time scales as well as to uncover interactions between the cellular processes....

  4. Stable Optical Phase Modulation With Micromirrors

    Science.gov (United States)

    2012-01-27

    to a voltage signal using a transimpedance amplifier with tranimpedance gain of Rf = 2 kΩ. The detected photocurrent of Iph = 0.6mA from 1.5mW of...the interferometer phase noise of δφmax = 4πrlδθmax/λ , which is then converted to the voltage noise at the output of the transimpedance amplifier by...The depth of modulation for a micromirror driven at mechanical resonance is amplified by the quality factor Q, enabling significant modulation with

  5. Components of cross-frequency modulation in health and disease.

    Science.gov (United States)

    Allen, Elena A; Liu, Jingyu; Kiehl, Kent A; Gelernter, Joel; Pearlson, Godfrey D; Perrone-Bizzozero, Nora I; Calhoun, Vince D

    2011-01-01

    The cognitive deficits associated with schizophrenia are commonly believed to arise from the abnormal temporal integration of information, however a quantitative approach to assess network coordination is lacking. Here, we propose to use cross-frequency modulation (cfM), the dependence of local high-frequency activity on the phase of widespread low-frequency oscillations, as an indicator of network coordination and functional integration. In an exploratory analysis based on pre-existing data, we measured cfM from multi-channel EEG recordings acquired while schizophrenia patients (n = 47) and healthy controls (n = 130) performed an auditory oddball task. Novel application of independent component analysis (ICA) to modulation data delineated components with specific spatial and spectral profiles, the weights of which showed covariation with diagnosis. Global cfM was significantly greater in healthy controls (F(1,175) = 9.25, P modulation at fronto-temporal electrodes was greater in patients (F(1,175) = 17.5, P modulation in schizophrenia patients was correlated with several polymorphisms in the gene for the α2-subunit of the GABA(A) receptor (GABRA2) as well as the total number of risk alleles in GABRA2 (r = 0.45, P < 0.01). Overall, our results indicate great promise for this approach in establishing patterns of cfM in health and disease and elucidating the roles of oscillatory interactions in functional connectivity.

  6. Time domain spectral phase encoding/DPSK data modulation using single phase modulator for OCDMA application.

    Science.gov (United States)

    Wang, Xu; Gao, Zhensen; Kataoka, Nobuyuki; Wada, Naoya

    2010-05-10

    A novel scheme using single phase modulator for simultaneous time domain spectral phase encoding (SPE) signal generation and DPSK data modulation is proposed and experimentally demonstrated. Array- Waveguide-Grating and Variable-Bandwidth-Spectrum-Shaper based devices can be used for decoding the signal directly in spectral domain. The effects of fiber dispersion, light pulse width and timing error on the coding performance have been investigated by simulation and verified in experiment. In the experiment, SPE signal with 8-chip, 20GHz/chip optical code patterns has been generated and modulated with 2.5 Gbps DPSK data using single modulator. Transmission of the 2.5 Gbps data over 34km fiber with BEROCDMA) and secure optical communication applications. (c) 2010 Optical Society of America.

  7. Dynamic Modeling of Phase Crossings in Two-Phase Flow

    DEFF Research Database (Denmark)

    Madsen, Søren; Veje, Christian; Willatzen, Morten

    2012-01-01

    by a high resolution finite difference scheme due to Kurganov and Tadmore. The homogeneous formulation requires a set of thermodynamic relations to cover the entire range from liquid to gas state. This leads a number of numerical challenges since these relations introduce discontinuities in the derivative...... of the variables and are usually very slow to evaluate. To overcome these challenges, we use an interpolation scheme with local refinement. The simulations show that the method handles crossing of the saturation lines for both liquid to two-phase and two-phase to gas regions. Furthermore, a novel result obtained...

  8. Auditory sensitivity to spectral modulation phase reversal as a function of modulation depth.

    Science.gov (United States)

    Buss, Emily; Grose, John

    2018-01-01

    The present study evaluated auditory sensitivity to spectral modulation by determining the modulation depth required to detect modulation phase reversal. This approach may be preferable to spectral modulation detection with a spectrally flat standard, since listeners appear unable to perform the task based on the detection of temporal modulation. While phase reversal thresholds are often evaluated by holding modulation depth constant and adjusting modulation rate, holding rate constant and adjusting modulation depth supports rate-specific assessment of modulation processing. Stimuli were pink noise samples, filtered into seven octave-wide bands (0.125-8 kHz) and spectrally modulated in dB. Experiment 1 measured performance as a function of modulation depth to determine appropriate units for adaptive threshold estimation. Experiment 2 compared thresholds in dB for modulation detection with a flat standard and modulation phase reversal; results supported the idea that temporal cues were available at high rates for the former but not the latter. Experiment 3 evaluated spectral modulation phase reversal thresholds for modulation that was restricted to either one or two neighboring bands. Flanking bands of unmodulated noise had a larger detrimental effect on one-band than two-band targets. Thresholds for high-rate modulation improved with increasing carrier frequency up to 2 kHz, whereas low-rate modulation appeared more consistent across frequency, particularly in the two-band condition. Experiment 4 measured spectral weights for spectral modulation phase reversal detection and found higher weights for bands in the spectral center of the stimulus than for the lowest (0.125 kHz) or highest (8 kHz) band. Experiment 5 compared performance for highly practiced and relatively naïve listeners, and found weak evidence of a larger practice effect at high than low spectral modulation rates. These results provide preliminary data for a task that may provide a better estimate of

  9. XPM-induced degradation of multilevel phase modulated channel caused by neighboring NRZ modulated channels

    DEFF Research Database (Denmark)

    Jensen, Jesper Bevensee; Schiellerup, G.; Peucheret, Christophe

    2008-01-01

    The impact of XPM from NRZ modulated channels on an 8-level phase modulated channel in a WDM system was investigated. Requirements on launch power are found. 400 km transmission was achieved with negligible penalty.......The impact of XPM from NRZ modulated channels on an 8-level phase modulated channel in a WDM system was investigated. Requirements on launch power are found. 400 km transmission was achieved with negligible penalty....

  10. WDM Phase-Modulated Millimeter-Wave Fiber Systems

    DEFF Research Database (Denmark)

    Yu, Xianbin; Prince, Kamau; Gibbon, Timothy Braidwood

    2012-01-01

    This chapter presents a computer simulation case study of two typical WDM phase-modulated millimeter-wave systems. The phase-modulated 60 GHz fiber multi-channel transmission systems employ single sideband (SSB) and double sideband subcarrier modulation (DSB-SC) schemes and present one of the lat......This chapter presents a computer simulation case study of two typical WDM phase-modulated millimeter-wave systems. The phase-modulated 60 GHz fiber multi-channel transmission systems employ single sideband (SSB) and double sideband subcarrier modulation (DSB-SC) schemes and present one...... of the latest research efforts in the rapidly emerging Radio-over-Fiber (RoF) application space for in-house access networks....

  11. Crystal structure of the commensurately modulated ζ phase of PAMC

    DEFF Research Database (Denmark)

    Harris, P.; Larsen, F.K.; Lebech, B.

    1994-01-01

    phase, indicating a 'lock-in' and phase shift between adjacent modulated layers. The modulation waves do not change much from the values of the epsilon phase, which confirms the lock-in of the modulation vector; only some components of the modulations of the propylammonium chains appear......The commensurately modulated zeta low-temperature phase of bis(propylammonium) tetrachloromanganate(II), [NH3(C3H7)]2MnCl4, has been determined at 8 K. a = 7.437 (5), b = 7.082 (5), c = 13.096 (8) Angstrom, alpha = 105.59 (1)degrees. Superspace group P2(1)/b(0 beta 0)(1) over bar s, with beta = 1...... to be significantly different, these chains appear to be responsible for the phase shift across the layers....

  12. Compact Energy Conversion Module, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This STTR project delivers a compact vibration-based Energy Conversion Module (ECM) that powers sensors for purposes such as structural health monitoring (SHM). NASA...

  13. Compact energy conversion module, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This STTR project delivers a compact vibration-based Energy Conversion Module (ECM) that powers sensors for purposes like structural health monitoring (SHM). NASA...

  14. Open-Loop Wide-Bandwidth Phase Modulation Techniques

    Directory of Open Access Journals (Sweden)

    Nitin Nidhi

    2011-01-01

    Full Text Available The ever-increasing growth in the bandwidth of wireless communication channels requires the transmitter to be wide-bandwidth and power-efficient. Polar and outphasing transmitter topologies are two promising candidates for such applications, in future. Both these architectures require a wide-bandwidth phase modulator. Open-loop phase modulation presents a viable solution for achieving wide-bandwidth operation. An overview of prior art and recent approaches for phase modulation is presented in this paper. Phase quantization noise cancellation was recently introduced to lower the out-of-band noise in a digital phase modulator. A detailed analysis on the impact of timing and quantization of the cancellation signal is presented. Noise generated by the transmitter in the receive band frequency poses another challenge for wide-bandwidth transmitter design. Addition of a noise transfer function notch, in a digital phase modulator, to reduce the noise in the receive band during phase modulation is described in this paper.

  15. All-optical phase modulation for integrated interferometric biosensors.

    Science.gov (United States)

    Dante, Stefania; Duval, Daphné; Sepúlveda, Borja; González-Guerrero, Ana Belen; Sendra, José Ramón; Lechuga, Laura M

    2012-03-26

    We present the theoretical and the experimental implementation of an all-optical phase modulation system in integrated Mach-Zehnder Interferometers to solve the drawbacks related to the periodic nature of the interferometric signal. Sensor phase is tuned by modulating the emission wavelength of low-cost commercial laser diodes by changing their output power. FFT deconvolution of the signal allows for direct phase readout, immune to sensitivity variations and to light intensity fluctuations. This simple phase modulation scheme increases the signal-to-noise ratio of the measurements in one order of magnitude, rendering in a sensor with a detection limit of 1.9·10⁻⁷ RIU. The viability of the all-optical modulation approach is demonstrated with an immunoassay detection as a biosensing proof of concept.

  16. Measuring high-frequency responses of an electro-optic phase modulator based on dispersion induced phase modulation to intensity modulation conversion

    Science.gov (United States)

    Zhang, Shangjian; Wang, Heng; Wang, Yani; Zou, Xinhai; Zhang, Yali; Liu, Shuang; Liu, Yong

    2014-11-01

    We investigate the phase modulation to intensity modulation conversion in dispersive fibers for measuring frequency responses of electro-optic phase modulators, and demonstrate two typical measurements with cascade path and fold-back path. The measured results achieve an uncertainty of less than 2.8% within 20 GHz. Our measurements show stable and repeatable results because the optical carrier and its phase-modulated sidebands are affected by the same fiber impairments. The proposed method requires only dispersive fibers and works without any small-signal assumption, which is applicable for swept frequency measurement at different driving levels and operating wavelengths.

  17. Considerations of digital phase modulation for narrowband satellite mobile communication

    Science.gov (United States)

    Grythe, Knut

    1990-01-01

    The Inmarsat-M system for mobile satellite communication is specified as a frequency division multiple access (FDMA) system, applying Offset Quadrature Phase Shift Keying (QPSK) for transmitting 8 kbit/sec in 10 kHz user channel bandwidth. We consider Digital Phase Modulation (DPM) as an alternative modulation format for INMARSAT-M. DPM is similar to Continuous Phase Modulation (CPM) except that DPM has a finite memory in the premodular filter with a continuous varying modulation index. It is shown that DPM with 64 states in the VA obtains a lower bit error rate (BER). Results for a 5 kHz system, with the same 8 kbit/sec transmitted bitstream, is also presented.

  18. Full Electroresistance Modulation in a Mixed-Phase Metallic Alloy

    Science.gov (United States)

    Liu, Z. Q.; Li, L.; Gai, Z.; Clarkson, J. D.; Hsu, S. L.; Wong, A. T.; Fan, L. S.; Lin, M.-W.; Rouleau, C. M.; Ward, T. Z.; Lee, H. N.; Sefat, A. S.; Christen, H. M.; Ramesh, R.

    2016-03-01

    We report a giant, ˜22 %, electroresistance modulation for a metallic alloy above room temperature. It is achieved by a small electric field of 2 kV /cm via piezoelectric strain-mediated magnetoelectric coupling and the resulting magnetic phase transition in epitaxial FeRh /BaTiO3 heterostructures. This work presents detailed experimental evidence for an isothermal magnetic phase transition driven by tetragonality modulation in FeRh thin films, which is in contrast to the large volume expansion in the conventional temperature-driven magnetic phase transition in FeRh. Moreover, all the experimental results in this work illustrate FeRh as a mixed-phase model system well similar to phase-separated colossal magnetoresistance systems with phase instability therein.

  19. Cross connecting absorber module inlets of multiple boiler units

    International Nuclear Information System (INIS)

    Cirillo, A.J.; Sperber, P.K.; Belavadi, V.N.; Mukherji, A.

    1991-01-01

    The retrofitting of scrubbers downstream of existing balanced draft boilers is often accomplished by the addition of induced draft (ID) booster fans. By creating a common plenum between the ID fans and the ID booster fans of two or more boiler-absorber trains, absorber module capacity may be shared among multiple boiler units. At Harrison Power Station, three (3) 4,900,000 lb/hour boilers (640 MWe Gross) will be linked through a common plenum. This sharing capability precludes the need to add standby module capacity, thereby saving capital dollars and keeping project critical path schedules, which typically run through absorber procurement and construction, to a minimum. Through damper placement in the ductwork cross connections, unitized boiler-absorber module operation or common plenum operation may be obtained, thus providing both operational flexibility and reliability. Additionally, open plenum operation allows the removal of an absorber unit from service, while keeping its associated boiler on line, thereby precluding 'cold starts' and maintaining overall unit availabilities. As either unitized or common plenum operation is possible with the cross connection, the furnace draft control systems of each boiler must be examined for varying load operation and trip conditions. This paper addresses the means by which to analyze such cross connection operational scenarios while maintaining compliance with furnace flame out safety guidelines, and will discuss the physical design considerations, ramifications and benefits of same, with select emphasis on what is being implemented at the Harrison Power Station

  20. Detector Modules for the CMS Pixel Phase 1 Upgrade

    CERN Document Server

    Zhu, De Hua; Berger, Pirmin; Meinhard, Maren Tabea; Starodumov, Andrey; Tavolaro, Vittorio Raoul

    2017-01-01

    The CMS Pixel phase 1 upgrade detector consists of 1184 modules with new design. An important part of the production is the module qualification and calibration, ensuring their proper functionality within the detector. This paper summarizes the qualification and calibration results of modules used in the innermost two detector layers with focus on methods using module-internal calibration signals. Extended characterizations on pixel level such as electronic noise and bump bond connectivity, optimization of operational parameters, sensor quality and thermal stress resistance were performed using a customized setup with controlled environment. It could be shown that the selected modules have on average $0.55 \\mathrm{ {}^{0\\!}\\!/\\!_{00} }\\, \\pm \\, 0.01 \\mathrm{ {}^{0\\!}\\!/\\!_{00} }\\,$ defective pixels and that all performance parameters stay within their specifications.

  1. Phase modulation mode of scanning ion conductance microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Li, Peng; Zhang, Changlin [State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Liu, Lianqing, E-mail: lqliu@sia.cn, E-mail: gli@engr.pitt.edu; Wang, Yuechao; Yang, Yang [State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016 (China); Li, Guangyong, E-mail: lqliu@sia.cn, E-mail: gli@engr.pitt.edu [Department of Electrical and Computer Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261 (United States)

    2014-08-04

    This Letter reports a phase modulation (PM) mode of scanning ion conductance microscopy. In this mode, an AC current is directly generated by an AC voltage between the electrodes. The portion of the AC current in phase with the AC voltage, which is the current through the resistance path, is modulated by the tip-sample distance. It can be used as the input of feedback control to drive the scanner in Z direction. The PM mode, taking the advantages of both DC mode and traditional AC mode, is less prone to electronic noise and DC drift but maintains high scanning speed. The effectiveness of the PM mode has been proven by experiments.

  2. Characterization of polarization-independent phase modulation method for practical plug and play quantum cryptography

    International Nuclear Information System (INIS)

    Kwon, Osung; Lee, Min-Soo; Woo, Min Ki; Park, Byung Kwon; Kim, Il Young; Kim, Yong-Su; Han, Sang-Wook; Moon, Sung

    2015-01-01

    We characterized a polarization-independent phase modulation method, called double phase modulation, for a practical plug and play quantum key distribution (QKD) system. Following investigation of theoretical backgrounds, we applied the method to the practical QKD system and characterized the performance through comparing single phase modulation (SPM) and double phase modulation. Consequently, we obtained repeatable and accurate phase modulation confirmed by high visibility single photon interference even for input signals with arbitrary polarization. Further, the results show that only 80% of the bias voltage required in the case of single phase modulation is needed to obtain the target amount of phase modulation. (paper)

  3. Mechanical modulation method for ultrasensitive phase measurements in photonics biosensing.

    Science.gov (United States)

    Patskovsky, S; Maisonneuve, M; Meunier, M; Kabashin, A V

    2008-12-22

    A novel polarimetry methodology for phase-sensitive measurements in single reflection geometry is proposed for applications in optical transduction-based biological sensing. The methodology uses altering step-like chopper-based mechanical phase modulation for orthogonal s- and p- polarizations of light reflected from the sensing interface and the extraction of phase information at different harmonics of the modulation. We show that even under a relatively simple experimental arrangement, the methodology provides the resolution of phase measurements as low as 0.007 deg. We also examine the proposed approach using Total Internal Reflection (TIR) and Surface Plasmon Resonance (SPR) geometries. For TIR geometry, the response appears to be strongly dependent on the prism material with the best values for high refractive index Si. The detection limit for Si-based TIR is estimated as 10(-5) in terms Refractive Index Units (RIU) change. SPR geometry offers much stronger phase response due to a much sharper phase characteristics. With the detection limit of 3.2*10(-7) RIU, the proposed methodology provides one of best sensitivities for phase-sensitive SPR devices. Advantages of the proposed method include high sensitivity, simplicity of experimental setup and noise immunity as a result of a high stability modulation.

  4. Code-modulated interferometric imaging system using phased arrays

    Science.gov (United States)

    Chauhan, Vikas; Greene, Kevin; Floyd, Brian

    2016-05-01

    Millimeter-wave (mm-wave) imaging provides compelling capabilities for security screening, navigation, and bio- medical applications. Traditional scanned or focal-plane mm-wave imagers are bulky and costly. In contrast, phased-array hardware developed for mass-market wireless communications and automotive radar promise to be extremely low cost. In this work, we present techniques which can allow low-cost phased-array receivers to be reconfigured or re-purposed as interferometric imagers, removing the need for custom hardware and thereby reducing cost. Since traditional phased arrays power combine incoming signals prior to digitization, orthogonal code-modulation is applied to each incoming signal using phase shifters within each front-end and two-bit codes. These code-modulated signals can then be combined and processed coherently through a shared hardware path. Once digitized, visibility functions can be recovered through squaring and code-demultiplexing operations. Pro- vided that codes are selected such that the product of two orthogonal codes is a third unique and orthogonal code, it is possible to demultiplex complex visibility functions directly. As such, the proposed system modulates incoming signals but demodulates desired correlations. In this work, we present the operation of the system, a validation of its operation using behavioral models of a traditional phased array, and a benchmarking of the code-modulated interferometer against traditional interferometer and focal-plane arrays.

  5. Preliminary Studies Of A Phase Modulation Technique For Measuring Chromaticity

    International Nuclear Information System (INIS)

    Tan, C.-Y.

    2006-01-01

    The classical method for measuring chromaticity is to slowly modulate the RF frequency and then measure the betatron tune excursion. The technique that is discussed in this paper instead modulates the phase of the RF and then the chromaticity is obtained by phase demodulating the betatron tune. This technique requires knowledge of the betatron frequency in real time in order for the phase to be demodulated. Fortunately, the Tevatron has a tune tracker based on the phase locked loop principle which fits this requirement. A preliminary study with this technique has showed that it is a promising method for doing continuous chromaticity measurement and raises the possibility of doing successful chromaticity feedback with it

  6. Phase transitions in spin systems with modulated order

    International Nuclear Information System (INIS)

    Coutinho Filho, M.D.

    1984-01-01

    Spin systems which may display modulated structures are treated. A layered Ising model with competing interactions between nearest and next-nearest layers in the presence of a magnetic field is studied. In the context of a mean-field approximation, the high-temperature region of the phase diagram is studied analytically. The Λ surface, separating the paramagnetic and the modulated phases, is bounded by two lines of tricritical points which join smoothly at the Lifshitz point and terminate at multicritical points, beyond which lines of critical and double critical end points are expected to appear. The low-temperature region is studied numerically. T-H phase diagrams, which exhibit a variety of modulated phases, for various values of the ratio of the strength of the competing interactions are constructed. A theoretical interpretation for the occurrence of a Lifshitz point in the field-temperature phase diagram of MnP is presented. These results, which are based on a X-Y localized spin Hamiltonian, are in qualitative agreement with recently reported experiments. In particular, asymptotic expressions are obtained for the phase boundaries, which meet tangentially at the Lifshitz point, and for some other thermodynamic quantities of interest, such as the longitudinal and transverse susceptibilities. (Author) [pt

  7. Modulated phase matching and high-order harmonic enhancement mediated by the carrier-envelope phase

    International Nuclear Information System (INIS)

    Faccio, Daniele; Serrat, Carles; Cela, Jose M.; Farres, Albert; Di Trapani, Paolo; Biegert, Jens

    2010-01-01

    The process of high-order harmonic generation in gases is numerically investigated in the presence of a few-cycle pulsed-Bessel-beam pump, featuring a periodic modulation in the peak intensity due to large carrier-envelope-phase mismatch. A two-decade enhancement in the conversion efficiency is observed and interpreted as the consequence of a mechanism known as a nonlinearly induced modulation in the phase mismatch.

  8. Charge modulation as fingerprints of phase-string triggered interference

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Zheng; Tian, Chushun; Jiang, Hong-Chen; Qi, Yang; Weng, Zheng-Yu; Zaanen, Jan

    2015-07-07

    Charge order appears to be an ubiquitous phenomenon in doped Mott insulators, which is currently under intense experimental and theoretical investigations particularly in the high T c cuprates. This phenomenon is conventionally understood in terms of Hartree-Fock-type mean-field theory. Here we demonstrate a mechanism for charge modulation which is rooted in the many-particle quantum physics arising in the strong coupling limit. Specifically, we consider the problem of a single hole in a bipartite t - J ladder. As a remnant of the fermion signs, the hopping hole picks up subtle phases pending the fluctuating spins, the so-called phase-string effect. We demonstrate the presence of charge modulations in the density matrix renormalization group solutions which disappear when the phase strings are switched off. This form of charge modulation can be understood analytically in a path-integral language with a mean-field-like approximation adopted, showing that the phase strings give rise to constructive interferences leading to self-localization. When the latter occurs, left- and right-moving propagating modes emerge inside the localization volume and their interference is responsible for the real space charge modulation.

  9. Longitudinal tracking with phase and amplitude modulated rf

    International Nuclear Information System (INIS)

    Caussyn, D.D.; Ball, M.; Brabson, B.

    1993-06-01

    Synchrotron motion was induced by phase shifting the rf of the Indiana University Cyclotron Facility (IUCF) cooler-synchrotron. The resulting coherent-bunch motion was tracked in longitudinal phase space for as many as 700,000 turns, or for over 350 synchrotron oscillations. Results of recent experimental studies of longitudinal motion in which the rf phase and amplitude were harmonically modulated are also presented. Comparisons of experimental data with numerical simulations, assuming independent particle motion, are made. Observed multiparticle effects are also discussed

  10. Phase-modulated radio over fiber multimode links.

    Science.gov (United States)

    Gasulla, Ivana; Capmany, José

    2012-05-21

    We present the first experimental demonstration of a phase-modulated MMF link implementing high-frequency digital transmission in a cost-effective solution based on direct detection. Successful subcarrier transmission of QPSK, 16-QAM and 64-QAM data channels for bit rates up to 120 Mb/s through a 5 km MMF link is achieved over the microwave region comprised between 6 and 20 GHz. The overall capacity of the proposed approach can be further increased by properly accommodating more passband channels in the operative frequency range determined by the phase-to-intensity conversion process provided by the dispersive nature of the optical fiber. In this sense, our results show the possibility of achieving an aggregate bit rate per length product of 144 Gb/s · km and confirm, in consequence, the possibility of broadband phase-modulated radio over fiber transmission through MMF links suitable for multichannel SCM signal distribution.

  11. Phase matching of high order harmonic generation using dynamic phase modulation caused by a non-collinear modulation pulse

    Science.gov (United States)

    Cohen, Oren; Kapteyn, Henry C.; Mumane, Margaret M.

    2010-02-16

    Phase matching high harmonic generation (HHG) uses a single, long duration non-collinear modulating pulse intersecting the driving pulse. A femtosecond driving pulse is focused into an HHG medium (such as a noble gas) to cause high-harmonic generation (HHG), for example in the X-ray region of the spectrum, via electrons separating from and recombining with gas atoms. A non-collinear pulse intersects the driving pulse within the gas, and modulates the field seen by the electrons while separated from their atoms. The modulating pulse is low power and long duration, and its frequency and amplitude is chosen to improve HHG phase matching by increasing the areas of constructive interference between the driving pulse and the HHG, relative to the areas of destructive interference.

  12. Spectral decomposition of single-tone-driven quantum phase modulation

    International Nuclear Information System (INIS)

    Capmany, Jose; Fernandez-Pousa, Carlos R

    2011-01-01

    Electro-optic phase modulators driven by a single radio-frequency tone Ω can be described at the quantum level as scattering devices where input single-mode radiation undergoes energy changes in multiples of ℎΩ. In this paper, we study the spectral representation of the unitary, multimode scattering operator describing these devices. The eigenvalue equation, phase modulation being a process preserving the photon number, is solved at each subspace with definite number of photons. In the one-photon subspace F 1 , the problem is equivalent to the computation of the continuous spectrum of the Susskind-Glogower cosine operator of the harmonic oscillator. Using this analogy, the spectral decomposition in F 1 is constructed and shown to be equivalent to the usual Fock-space representation. The result is then generalized to arbitrary N-photon subspaces, where eigenvectors are symmetrized combinations of N one-photon eigenvectors and the continuous spectrum spans the entire unit circle. Approximate normalizable one-photon eigenstates are constructed in terms of London phase states truncated to optical bands. Finally, we show that synchronous ultrashort pulse trains represent classical field configurations with the same structure as these approximate eigenstates, and that they can be considered as approximate eigenvectors of the classical formulation of phase modulation.

  13. Spectral decomposition of single-tone-driven quantum phase modulation

    Energy Technology Data Exchange (ETDEWEB)

    Capmany, Jose [ITEAM Research Institute, Univ. Politecnica de Valencia, 46022 Valencia (Spain); Fernandez-Pousa, Carlos R, E-mail: c.pousa@umh.es [Signal Theory and Communications, Department of Physics and Computer Science, Univ. Miguel Hernandez, 03202 Elche (Spain)

    2011-02-14

    Electro-optic phase modulators driven by a single radio-frequency tone {Omega} can be described at the quantum level as scattering devices where input single-mode radiation undergoes energy changes in multiples of {h_bar}{Omega}. In this paper, we study the spectral representation of the unitary, multimode scattering operator describing these devices. The eigenvalue equation, phase modulation being a process preserving the photon number, is solved at each subspace with definite number of photons. In the one-photon subspace F{sub 1}, the problem is equivalent to the computation of the continuous spectrum of the Susskind-Glogower cosine operator of the harmonic oscillator. Using this analogy, the spectral decomposition in F{sub 1} is constructed and shown to be equivalent to the usual Fock-space representation. The result is then generalized to arbitrary N-photon subspaces, where eigenvectors are symmetrized combinations of N one-photon eigenvectors and the continuous spectrum spans the entire unit circle. Approximate normalizable one-photon eigenstates are constructed in terms of London phase states truncated to optical bands. Finally, we show that synchronous ultrashort pulse trains represent classical field configurations with the same structure as these approximate eigenstates, and that they can be considered as approximate eigenvectors of the classical formulation of phase modulation.

  14. Dynamic modulation of epileptic high frequency oscillations by the phase of slower cortical rhythms.

    Science.gov (United States)

    Ibrahim, George M; Wong, Simeon M; Anderson, Ryan A; Singh-Cadieux, Gabrielle; Akiyama, Tomoyuki; Ochi, Ayako; Otsubo, Hiroshi; Okanishi, Tohru; Valiante, Taufik A; Donner, Elizabeth; Rutka, James T; Snead, O Carter; Doesburg, Sam M

    2014-01-01

    Pathological high frequency oscillations (pHFOs) have been proposed to be robust markers of epileptic cortex. Oscillatory activity below this frequency range has been shown to be modulated by phase of lower frequency oscillations. Here, we tested the hypothesis that dynamic cross-frequency interactions involving pHFOs are concentrated within the epileptogenic cortex. Intracranial electroencephalographic recordings from 17 children with medically-intractable epilepsy secondary to focal cortical dysplasia were obtained. A time-resolved analysis was performed to determine topographic concentrations and dynamic changes in cross-frequency amplitude-to-phase coupling (CFC). CFC between pHFOs and the phase of theta and alpha rhythms was found to be significantly elevated in the seizure-onset zone compared to non-epileptic regions (pfrequency oscillations at which pHFO amplitudes were maximal was inconsistent at seizure initiation, yet consistently at the trough of the low frequency rhythm at seizure termination. Amplitudes of pHFOs were most significantly modulated by the phase of alpha-band oscillations (p<0.01). These results suggest that increased CFC between pHFO amplitude and alpha phase may constitute a marker of epileptogenic brain areas and may be relevant for understanding seizure dynamics. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. Phase ambiguity resolution for offset QPSK modulation systems

    Science.gov (United States)

    Nguyen, Tien M. (Inventor)

    1991-01-01

    A demodulator for Offset Quaternary Phase Shift Keyed (OQPSK) signals modulated with two words resolves eight possible combinations of phase ambiguity which may produce data error by first processing received I(sub R) and Q(sub R) data in an integrated carrier loop/symbol synchronizer using a digital Costas loop with matched filters for correcting four of eight possible phase lock errors, and then the remaining four using a phase ambiguity resolver which detects the words to not only reverse the received I(sub R) and Q(sub R) data channels, but to also invert (complement) the I(sub R) and/or Q(sub R) data, or to at least complement the I(sub R) and Q(sub R) data for systems using nontransparent codes that do not have rotation direction ambiguity.

  16. Cavity Voltage Phase Modulation MD blocks 3 and 4

    CERN Document Server

    Mastoridis, T; Butterworth, A; Molendijk, J; Tuckmantel, J

    2013-01-01

    The LHC RF/LLRF system is currently setup for extremely stable RF voltage to minimize transient beam loading effects. The present scheme cannot be extended beyond nominal beam current since the demanded power would push the klystrons to saturation. For beam currents above nominal (and possibly earlier), the cavity phase modulation by the beam (transient beam loading) will not be corrected, but the strong RF feedback and One-Turn Delay feedback will still be active for RF loop and beam stability in physics. To achieve this, the voltage set point should be adapted for each bunch. The goal of these MDs was to test thefirmware version of an iterative algorithm that adjusts the voltage set point to achieve the optimal phase modulation for klystron forward power considerations.

  17. An amplitude and phase hybrid modulation Fresnel diffractive optical element

    Science.gov (United States)

    Li, Fei; Cheng, Jiangao; Wang, Mengyu; Jin, Xueying; Wang, Keyi

    2018-04-01

    An Amplitude and Phase Hybrid Modulation Fresnel Diffractive Optical Element (APHMFDOE) is proposed here. We have studied the theory of APHMFDOE and simulated the focusing properties of it along the optical axis, which show that the focus can be blazed to other positions with changing the quadratic phase factor. Moreover, we design a Composite Fresnel Diffraction Optical Element (CFDOE) based on the characteristics of APHMFDOE. It greatly increases the outermost zone width without changing the F-number, which brings a lot of benefits to the design and processing of diffraction device. More importantly, the diffraction efficiency of the CFDOE is almost unchanged compared with AFZP at the same focus.

  18. Modulated phases of phospholipid bilayers induced by tocopherols.

    Science.gov (United States)

    Kamal, Md Arif; Raghunathan, V A

    2012-11-01

    The influence of α-, γ- and δ-tocopherols on the structure and phase behavior of dipalmitoyl phosphatidylcholine (DPPC) bilayers has been determined from X-ray diffraction studies on oriented multilayers. In all the three cases the main-transition temperature (T(m)) of DPPC was found to decrease with increasing tocopherol concentration up to around 25 mol%. Beyond this the main transition is suppressed in the case of γ-tocopherol, whereas T(m) becomes insensitive to composition in the other two cases. The pre-transition is found to be suppressed over a narrow tocopherol concentration range between 7.5 and 10 mol% in DPPC-γ-tocopherol and DPPC-δ-tocopherol bilayers, and the ripple phase occurs down to the lowest temperature studied. In all the three cases a modulated phase is observed above a tocopherol concentration of about 10 mol%, which is similar to the P(β) phase reported in DPPC-cholesterol bilayers. This phase is found to occur even in excess water conditions at lower tocopherol concentrations, and consists of bilayers with periodic height modulation. These results indicate the ability of tocopherols to induce local curvature in membranes, which could be important for some of their biological functions. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Transport reduction via shear flow modification of the cross phase

    International Nuclear Information System (INIS)

    Ware, A.S.; Terry, P.W.; Diamond, P.H.; Carreras, B.A.

    1996-01-01

    As a model example of the effect of E x B shear flow on the cross phase between electrostatic potential and pressure fluctuations, a nonlinear theory of resistive pressure gradient driven turbulence (RPGDT) in a shear flow is presented. This work builds on numerical studies of RPGDT, which have shown that both flow shear and curvature can affect the cross phase as well as the fluctuation levels. In this work, we show that the effect of shear flow on transport can be expressed through the temporal response of pressure to potential. It is shown heuristically that even in the case where the fluctuation levels are not modified, the flow shear still acts to reduce the phase angle between potential and pressure fluctuations, thereby suppressing transport. The scaling of the cross phase with flow shear and flow curvature is presented. (author)

  20. Phase modulated 2D HSQC-TOCSY for unambiguous assignment of overlapping spin systems

    Science.gov (United States)

    Singh, Amrinder; Dubey, Abhinav; Adiga, Satish K.; Atreya, Hanudatta S.

    2018-01-01

    We present a new method that allows one to unambiguously resolve overlapping spin systems often encountered in biomolecular systems such as peptides and proteins or in samples containing a mixture of different molecules such as in metabolomics. We address this problem using the recently proposed phase modulation approach. By evolving the 1H chemical shifts in a conventional two dimensional (2D) HSQC-TOCSY experiment for a fixed delay period, the phase/intensity of set of cross peaks belonging to one spin system are modulated differentially relative to those of its overlapping counterpart, resulting in their discrimination and recognition. The method thus accelerates the process of identification and resonance assignment of individual compounds in complex mixtures. This approach facilitated the assignment of molecules in the embryo culture medium used in human assisted reproductive technology.

  1. The dressed atom as binary phase modulator: towards attojoule/edge optical phase-shift keying.

    Science.gov (United States)

    Kerckhoff, Joseph; Armen, Michael A; Pavlichin, Dmitri S; Mabuchi, Hideo

    2011-03-28

    We use a single 133Cs atom strongly coupled to an optical resonator to induce random binary phase modulation of a near infra-red, ∼ 500 pW laser beam, with each modulation edge caused by the dissipation of a single photon (≈ 0.23 aJ) by the atom. While our ability to deterministically induce phase edges with an additional optical control beam is limited thus far, theoretical analysis of an analogous, solid-state system indicates that efficient external control should be achievable in demonstrated nanophotonic systems.

  2. A Method and an Apparatus for Generating a Phase-Modulated Wave Front of Electromagnetic Radiation

    DEFF Research Database (Denmark)

    2002-01-01

    The present invention provides a method and a system for generating a phase-modulated wave front. According to the present invention, the spatial phase-modulation is not performed on the different parts of the wave front individually as in known POSLMs. Rather, the spatial phase-modulation of the...

  3. Optical phase conjugation for time-domain undoing of dispersive self-phase-modulation effects

    International Nuclear Information System (INIS)

    Fisher, R.A.; Suydam, B.R.; Yevick, D.

    1983-01-01

    We show that the temporal distortion and spectral broadening of a pulse generated by the combined effects of group-velocity dispersion and self-phase modulation is removed by reflection of a cw-pumped, broadband, unity-reflecting Kerr-like optical phase conjugator followed by retraversal of the nonlinear medium. We also examine numerically the effects of finite linear loss in the material, of nonunity conjugate reflectivity, and of finite conjugator thickness

  4. Particle separation by phase modulated surface acoustic waves.

    Science.gov (United States)

    Simon, Gergely; Andrade, Marco A B; Reboud, Julien; Marques-Hueso, Jose; Desmulliez, Marc P Y; Cooper, Jonathan M; Riehle, Mathis O; Bernassau, Anne L

    2017-09-01

    High efficiency isolation of cells or particles from a heterogeneous mixture is a critical processing step in lab-on-a-chip devices. Acoustic techniques offer contactless and label-free manipulation, preserve viability of biological cells, and provide versatility as the applied electrical signal can be adapted to various scenarios. Conventional acoustic separation methods use time-of-flight and achieve separation up to distances of quarter wavelength with limited separation power due to slow gradients in the force. The method proposed here allows separation by half of the wavelength and can be extended by repeating the modulation pattern and can ensure maximum force acting on the particles. In this work, we propose an optimised phase modulation scheme for particle separation in a surface acoustic wave microfluidic device. An expression for the acoustic radiation force arising from the interaction between acoustic waves in the fluid was derived. We demonstrated, for the first time, that the expression of the acoustic radiation force differs in surface acoustic wave and bulk devices, due to the presence of a geometric scaling factor. Two phase modulation schemes are investigated theoretically and experimentally. Theoretical findings were experimentally validated for different mixtures of polystyrene particles confirming that the method offers high selectivity. A Monte-Carlo simulation enabled us to assess performance in real situations, including the effects of particle size variation and non-uniform acoustic field on sorting efficiency and purity, validating the ability to separate particles with high purity and high resolution.

  5. Phase-modulation interferometer for ICF-target characterization

    International Nuclear Information System (INIS)

    Cooper, D.E.

    1981-01-01

    Characterization requirements for high gain laser fusion targets are severe. We are required to detect defects on the surfaces of opaque and transparent shells with an amplitude resolution of +- 5 nm and a spatial resolution of 1 to 10 μm. To achieve this we have developed a laser-illuminated phase-modulation interferometer. This instrument is based on a photoelastic polarization modulation technique which allows one to convert phase information into an intensity modulation which can be easily and sensitively measured using ac signal processing techniques. This interferometer has detected path length changes as small as 1 nm and the required spatial resolution is assured by using a microscope objective to focus the probe laser beam down to a small (approx. 1 μm) spot on the surface of a microballoon. The interferometer will soon be coupled to an LSI-11 controlled 4π sphere manipulator which will allow us to automatically inspect the entire surface area of a target sphere

  6. Effects of signal modulation and coloured cross-correlation of coloured noises on the diffusion of a harmonic oscillator

    Institute of Scientific and Technical Information of China (English)

    Liu Li; Zhang Liang-Ying; Cao Li

    2009-01-01

    The diffusion in a harmonic oscillator driven by coloured noises ζ(t) and η(t) with coloured cross-correlation in which one of the noises is modulated by a biased periodic signal is investigated. The exact expression of diffusion coefficient d as a function of noise parameter, signal parameter, and oscillator frequency is derived. The findings in this paper are as follows. 1) The curves of d versus noise intensity D and d versus noises cross-correlation time τ_3 exist as two different phases. The transition between the two phases arises from the change of the cross-correlation coefficient λ of the two Orustein-Uhlenbeck (O-U) noises. 2) Changing the value of τ3, the curves of d versus Q, the intensity of colored noise that is modulated by the signal, can transform from a phase having a minimum to a monotonic phase. 3)Changing the value of signal amplitude A, d versus Q curves can transform from a phase having a minimum to a monotonic phase. The above-mentioned results demonstrate that a like noise-induced transition appears in the model.

  7. Effects of signal modulation and coloured cross-correlation of coloured noises on the diffusion of a harmonic oscillator

    International Nuclear Information System (INIS)

    Li, Liu; Li, Cao; Liang-Ying, Zhang

    2009-01-01

    The diffusion in a harmonic oscillator driven by coloured noises ζ(t) and η(t) with coloured cross-correlation in which one of the noises is modulated by a biased periodic signal is investigated. The exact expression of diffusion coefficient d as a function of noise parameter, signal parameter, and oscillator frequency is derived. The findings in this paper are as follows. 1) The curves of d versus noise intensity D and d versus noises cross-correlation time τ 3 exist as two different phases. The transition between the two phases arises from the change of the cross-correlation coefficient λ of the two Ornstein–Uhlenbeck (O-U) noises. 2) Changing the value of τ 3 , the curves of d versus Q, the intensity of colored noise that is modulated by the signal, can transform from a phase having a minimum to a monotonic phase. 3) Changing the value of signal amplitude A, d versus Q curves can transform from a phase having a minimum to a monotonic phase. The above-mentioned results demonstrate that a like noise-induced transition appears in the model. (general)

  8. Modulating patterns of two-phase flow with electric fields.

    Science.gov (United States)

    Liu, Dingsheng; Hakimi, Bejan; Volny, Michael; Rolfs, Joelle; Anand, Robbyn K; Turecek, Frantisek; Chiu, Daniel T

    2014-07-01

    This paper describes the use of electro-hydrodynamic actuation to control the transition between three major flow patterns of an aqueous-oil Newtonian flow in a microchannel: droplets, beads-on-a-string (BOAS), and multi-stream laminar flow. We observed interesting transitional flow patterns between droplets and BOAS as the electric field was modulated. The ability to control flow patterns of a two-phase fluid in a microchannel adds to the microfluidic tool box and improves our understanding of this interesting fluid behavior.

  9. Method of phase space beam dilution utilizing bounded chaos generated by rf phase modulation

    Directory of Open Access Journals (Sweden)

    Alfonse N. Pham

    2015-12-01

    Full Text Available This paper explores the physics of chaos in a localized phase-space region produced by rf phase modulation applied to a double rf system. The study can be exploited to produce rapid particle bunch broadening exhibiting longitudinal particle distribution uniformity. Hamiltonian models and particle-tracking simulations are introduced to understand the mechanism and applicability of controlled particle diffusion. When phase modulation is applied to the double rf system, regions of localized chaos are produced through the disruption and overlapping of parametric resonant islands and configured to be bounded by well-behaved invariant tori to prevent particle loss. The condition of chaoticity and the degree of particle dilution can be controlled by the rf parameters. The method has applications in alleviating adverse space-charge effects in high-intensity beams, particle bunch distribution uniformization, and industrial radiation-effects experiments.

  10. Detection and characterization of single nanoparticles by interferometric phase modulated ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Barroso, F.; Bosch, S.; Tort, N.; Arteaga, O. [Universitat de Barcelona, IN2UB, Dep. Fisica Aplicada i Optica, c/Marti i Franques 1, 08028 (Spain); Sancho-Parramon, J. [Rudjer Boskovic Institute, Bijenicka c. 54, Zagreb 10002 (Croatia); Jover, E.; Bertran, E. [Universitat de Barcelona, IN2UB, Dep. Fisica Aplicada i Optica, c/Marti i Franques 1, 08028 (Spain); Canillas, A., E-mail: acanillas@ub.ed [Universitat de Barcelona, IN2UB, Dep. Fisica Aplicada i Optica, c/Marti i Franques 1, 08028 (Spain)

    2011-02-28

    We introduce a new measurement system called Nanopolar interferometer devoted to monitor and characterize single nanoparticles which is based on the interferometric phase modulated ellipsometry technique. The system collects the backscattered light by the particles in the solid angle subtended by a microscope objective and then analyses its frequency components. The results for the detection of 2 {mu}m and 50 nm particles are explained in terms of a cross polarization effect of the polarization vectors when the beam converts from divergent to parallel in the microscope objective. This explanation is supported with the results of the optical modelling using the exact Mie theory for the light scattered by the particles.

  11. Detection and characterization of single nanoparticles by interferometric phase modulated ellipsometry

    International Nuclear Information System (INIS)

    Barroso, F.; Bosch, S.; Tort, N.; Arteaga, O.; Sancho-Parramon, J.; Jover, E.; Bertran, E.; Canillas, A.

    2011-01-01

    We introduce a new measurement system called Nanopolar interferometer devoted to monitor and characterize single nanoparticles which is based on the interferometric phase modulated ellipsometry technique. The system collects the backscattered light by the particles in the solid angle subtended by a microscope objective and then analyses its frequency components. The results for the detection of 2 μm and 50 nm particles are explained in terms of a cross polarization effect of the polarization vectors when the beam converts from divergent to parallel in the microscope objective. This explanation is supported with the results of the optical modelling using the exact Mie theory for the light scattered by the particles.

  12. Broadband homonuclear TOCSY with amplitude and phase-modulated RF mixing schemes

    International Nuclear Information System (INIS)

    Kirschstein, Anika; Herbst, Christian; Riedel, Kerstin; Carella, Michela; Leppert, Joerg; Ohlenschlaeger, Oliver; Goerlach, Matthias; Ramachandran, Ramadurai

    2008-01-01

    We have explored the design of broadband scalar coupling mediated 13 C- 13 C and cross-relaxation suppressed 1 H- 1 H TOCSY sequences employing phase/amplitude modulated inversion pulses. Considering a variety of supercycles, pulsewidths and a RF field strength of 10 kHz, the Fourier coefficients defining the amplitude and phase modulation profiles of the 180 deg. pulses were optimised numerically so as to obtain efficient magnetisation transfer within the desired range of resonance offsets. The coherence transfer characteristics of the mixing schemes were assessed via numerical simulations and experimental measurements and were compared with commonly used sequences based on rectangular RF pulses. The efficacies of the clean 1 H- 1 H TOCSY sequences were also examined via numerical simulations for application to weakly oriented systems and sequences with efficient, broadband and clean dipolar transfer characteristics were identified. In general, the amplitude and phase modulated TOCSY sequences presented here have moderately better performance characteristics than the sequences currently employed in biomolecular NMR spectroscopy

  13. A Phase 1 Human Immunodeficiency Virus Vaccine Trial for Cross-Profiling the Kinetics of Serum and Mucosal Antibody Responses to CN54gp140 Modulated by Two Homologous Prime-Boost Vaccine Regimens

    Directory of Open Access Journals (Sweden)

    Sven Kratochvil

    2017-05-01

    Full Text Available A key aspect to finding an efficacious human immunodeficiency virus (HIV vaccine is the optimization of vaccine schedules that can mediate the efficient maturation of protective immune responses. In the present study, we investigated the effect of alternate booster regimens on the immune responses to a candidate HIV-1 clade C CN54gp140 envelope protein, which was coadministered with the TLR4-agonist glucopyranosyl lipid A-aqueous formulation. Twelve study participants received a common three-dose intramuscular priming series followed by a final booster at either 6 or 12 months. The two homologous prime-boost regimens were well tolerated and induced CN54gp140-specific responses that were observed in both the systemic and mucosal compartments. Levels of vaccine-induced IgG-subclass antibodies correlated significantly with FcγR engagement, and both vaccine regimens were associated with strikingly similar patterns in antibody titer and FcγR-binding profiles. In both groups, identical changes in the antigen (Ag-specific IgG-subclass fingerprint, leading to a decrease in IgG1 and an increase in IgG4 levels, were modulated by booster injections. Here, the dissection of immune profiles further supports the notion that prime-boost strategies are essential for the induction of diverse Ag-specific HIV-1 responses. The results reported here clearly demonstrate that identical responses were effectively and safely induced by both vaccine regimens, indicating that an accelerated 6-month regimen could be employed for the rapid induction of immune responses against CN54gp140 with no apparent impact on the overall quality of the induced immune response. (This study has been registered at http://ClinicalTrials.gov under registration no. NCT01966900.

  14. Phase Modulation Method for Control Systems of Rotary Machine Parameters

    Directory of Open Access Journals (Sweden)

    V. V. Sychev

    2014-01-01

    Full Text Available Traditionally, vibration-based diagnostics takes the main place in a large complex of technical control means of rotary machine operation. It allows us to control the onset of extreme limit states of operating construction and its elements. However, vibration-based diagnostics is incapable to provide differentiated information about the condition of particular units, type of fault and point of its occurrence.From the practical experience of optoelectronic sensors development, methods of phase coding information about the behavior of the investigated object are known. They allow us to overcome the abovementioned disadvantage of vibration-based diagnostics through the modulation of the reflected radiation from the object. This phase modulation is performed with the image analyzers, in which the modulating raster (alternating transparent and nontransparent sectors is designed so, that the carrier frequency of oscillations is absent (suppressed in frequency spectrum, and all useful information can be found in the side frequencies.Carrier frequency suppression appears for two complete turns of the modulating raster. Each time during this process oscillations have a 180° phase shift (hop relatively to the initial oscillation on the boundary of each turn. It leads to a substantial increase in signal/noise ratio and possibility to conduct high-accuracy diagnostics.The principle of the pseudo inversion is used for measurements to suppress an adverse effect of various factors in dynamic control system. For this principle the leaving and returned beams practically go on the same way with small spatial shift. This shift occurs then the leaving beam reflects from a basic surface and the reflected – from the measured surface of the object. Therefore the measurements become insensitive to any other errors of system, except relative position of system «model-object».The main advantages of such measurements are the following:- system steadiness to error

  15. Characterisation of thin films by phase modulated spectroscopic ellipsometry

    International Nuclear Information System (INIS)

    Bhattacharyya, D.; Das, N.C.

    1998-07-01

    A wide variety of thin film coatings, deposited by different techniques and with potential applications in various important areas, have been characterised by the Phase Modulated Spectroscopic Ellipsometer, installed recently in the Spectroscopy Division, B.A.R.C. The Phase Modulated technique provides a faster and more accurate data acquisition process than the conventional ellipsometry. The measured Ellipsometry spectra are fitted with theoretical spectra generated assuming an appropriate model regarding the sample. The fittings have been done objectively by minimising the squared difference (χ 2 ) between the measured and calculated values of the ellipsometric parameters and thus accurate information have been derived regarding the thickness and optical constants (viz, the refractive index and extinction coefficient) of the different layers, the surface roughness and the inhomogeneities present in the layers. Measurements have been done on (i) ion-implanted Si-wafers to investigate the formation of SiC layers, (ii) phenyl- silane coating on glass to investigate the surface modifications achieved for better adsorption of rhodamine dye on glass, (iii) GaN films on quartz to investigate the formation of high quality GaN layers by sputtering of GaAs targets, (iv) Diamond-like-coating (DLC) samples prepared by Chemical Vapour Deposition (CVD) to investigate the optical properties which would ultimately lead to an accurate estimation of the ratio of sp 3 and sp 2 bonded carbon atoms in the films and (v) SS 304 under different surface treatments to investigate the growth of different passive films. (author)

  16. Current Status of the Pixel Phase I Upgrade in CMS: Barrel Module Production

    CERN Document Server

    Bartek, Rachel

    2016-01-01

    The silicon pixel detector is the innermost component of the CMS tracking system, providing high precision space point measurements of charged particle trajectories. Before 2018 the instantaneous luminosity of the LHC is expected to reach about 2~x~$10^{34}~\\rm{cm}^{-2}\\rm{s}^{-1}$, which will significantly increase the number of interactions per bunch crossing. To maintain a high tracking efficiency, CMS has planned to replace the current pixel system during phase I by a new lightweight detector, equipped with an additional 4th layer in the barrel, and one additional forward/backward disk. The present status of barrel modules production will be presented, including preliminary results from tests on the first production pixel modules of the new pixel tracker.

  17. Cross-Modulation Interference with Lateralization of Mixed-Modulated Waveforms

    Science.gov (United States)

    Hsieh, I-Hui; Petrosyan, Agavni; Goncalves, Oscar F.; Hickok, Gregory; Saberi, Kourosh

    2010-01-01

    Purpose: This study investigated the ability to use spatial information in mixed-modulated (MM) sounds containing concurrent frequency-modulated (FM) and amplitude-modulated (AM) sounds by exploring patterns of interference when different modulation types originated from different loci as may occur in a multisource acoustic field. Method:…

  18. Observation of modulation speed enhancement, frequency modulation suppression, and phase noise reduction by detuned loading in a coupled-cavity semiconductor laser

    OpenAIRE

    Vahala, Kerry; Paslaski, Joel; Yariv, Amnon

    1985-01-01

    Simultaneous direct modulation response enhancement, phase noise (linewidth) reduction, and frequency modulation suppression are produced in a coupled-cavity semiconductor laser by the detuned loading mechanism.

  19. Fully interferometric controllable anomalous refraction efficiency using cross modulation with plasmonic metasurfaces.

    Science.gov (United States)

    Liu, Zhaocheng; Chen, Shuqi; Li, Jianxiong; Cheng, Hua; Li, Zhancheng; Liu, Wenwei; Yu, Ping; Xia, Ji; Tian, Jianguo

    2014-12-01

    We present a method of fully interferometric, controllable anomalous refraction efficiency by introducing cross-modulated incident light based on plasmonic metasurfaces. Theoretical analyses and numerical simulations indicate that the anomalous and ordinary refracted beams generated from two opposite-helicity incident beams and following the generalized Snell's law will have a superposition for certain incident angles, and the anomalous refraction efficiency can be dynamically controlled by changing the relative phase of the incident sources. As the incident wavelength nears the resonant wavelength of the plasmonic metasurfaces, two equal-amplitude incident beams with opposite helicity can be used to control the anomalous refraction efficiency. Otherwise, two unequal-amplitude incident beams with opposite helicity can be used to fully control the anomalous refraction efficiency. This Letter may offer a further step in the development of controllable anomalous refraction.

  20. Fluid-elastic vibration in two-phase cross flow

    International Nuclear Information System (INIS)

    Sasakawa, T.; Serizawa, A.; Kawara, Z.

    2003-01-01

    The present work aims at clarifying the mechanisms of fluid elastic vibration of tube bundles in two-phase cross flow. The experiment is conducted using air-water two-phase flow under atmospheric pressure. The test section is a 1.03m long transparent acrylic square duct with 128 x 128 mm 2 cross section, which consists of 3 rod-rows with 5 rods in each row. The rods are 125mm long aluminum rods with 22 mm in diameter (p/D=1.45). The natural frequency of rod vibration is about 30Hz. The result indicated a diversion of observed trend in vibration behavior depending on two-phase flow patterns either bubbly flow or churn flow. Specifically, in churn flow, the fluid elastic vibration has been observed to occur when the frequency in void fraction fluctuation approached to the natural frequency of the rods, but this was not the case in fluid elastic vibration in bubbly flow. This fact suggests the existence of mechanisms closely coupled with two-phase flow structures depending on the flow patterns, that is, static two-phase character-controlled mechanism in bubbly flow and dynamic character- controlled in churn flow

  1. QPSK Modulator with Continuous Phase and Fast Response Based on Phase-Locked Loop

    Directory of Open Access Journals (Sweden)

    L. Kirasamuthranon

    2017-06-01

    Full Text Available Among M-phase shift keying (M-PSK schemes, quadrature phase-shift keying (QPSK is used most often because of its efficient bandwidth consumption. However, in comparison with minimum-shift keying, which has continuous phase transitions, QPSK requires a higher bandwidth to transmit a signal. This article focuses on the phase transitions in QPSK signals, and a QPSK modulator based on a phase-locked loop (PLL is proposed. The PLL circuit in the proposed system differs from that of conventional PLL circuits because a three-input XOR gate and a summing circuit are used. With these additional components, the proposed PLL provides a continuous phase change in the QPSK signal. Consequently, the required bandwidth for transmitting the QPSK signal when using the proposed circuit is less than that for a conventional QPSK signal with a discontinuous phase. The analytical results for the proposed system in the time domain agree well with the experimental and simulation results of the circuit. Both the theoretical and experimental results thus confirm that the proposed technique can be realized in real-world applications.

  2. Coherent Detection of Wavelength Division Multiplexed Phase-Modulated Radio-over-Fibre Signals

    DEFF Research Database (Denmark)

    Zibar, Darko; Yu, Xianbin; Peucheret, Christophe

    2008-01-01

    A WDM phase-modulated Radio-over-Fibre link using digital coherent detection is experimentally demonstrated. 3 times 50 Mb/s WDM transmission of a BPSK modulated 5 GHz RF carrier is achieved over 25 km.......A WDM phase-modulated Radio-over-Fibre link using digital coherent detection is experimentally demonstrated. 3 times 50 Mb/s WDM transmission of a BPSK modulated 5 GHz RF carrier is achieved over 25 km....

  3. Cross-phase modulational instability in an elliptical birefringent fiber ...

    Indian Academy of Sciences (India)

    measured by a gain given byG = Imk where Imk denotes the imaginary part ofk. We next investigate the MI conditions for various regimes of pulse propagation. We now discuss the results obtained for the three different cases mentioned in Ü2. (i) MI condition governing the generation of ultrashort pulses in the femto second ...

  4. Phase modulated high density collinear holographic data storage system with phase-retrieval reference beam locking and orthogonal reference encoding.

    Science.gov (United States)

    Liu, Jinpeng; Horimai, Hideyoshi; Lin, Xiao; Huang, Yong; Tan, Xiaodi

    2018-02-19

    A novel phase modulation method for holographic data storage with phase-retrieval reference beam locking is proposed and incorporated into an amplitude-encoding collinear holographic storage system. Unlike the conventional phase retrieval method, the proposed method locks the data page and the corresponding phase-retrieval interference beam together at the same location with a sequential recording process, which eliminates piezoelectric elements, phase shift arrays and extra interference beams, making the system more compact and phase retrieval easier. To evaluate our proposed phase modulation method, we recorded and then recovered data pages with multilevel phase modulation using two spatial light modulators experimentally. For 4-level, 8-level, and 16-level phase modulation, we achieved the bit error rate (BER) of 0.3%, 1.5% and 6.6% respectively. To further improve data storage density, an orthogonal reference encoding multiplexing method at the same position of medium is also proposed and validated experimentally. We increased the code rate of pure 3/16 amplitude encoding method from 0.5 up to 1.0 and 1.5 using 4-level and 8-level phase modulation respectively.

  5. Fully reconfigurable 2x2 optical cross-connect using tunable wavelength switching modules

    DEFF Research Database (Denmark)

    Liu, Fenghai; Zheng, Xueyan; Pedersen, Rune Johan Skullerud

    2001-01-01

    A modular tunable wavelength switching module is proposed and used to construct 2x2 fully reconfigurable optical cross-connects. Large size optical switch is avoided in the OXC and it is easy to upgrade to more wavelength channels.......A modular tunable wavelength switching module is proposed and used to construct 2x2 fully reconfigurable optical cross-connects. Large size optical switch is avoided in the OXC and it is easy to upgrade to more wavelength channels....

  6. Ring resonator-based on-chip modulation transformer for high-performance phase-modulated microwave photonic links.

    Science.gov (United States)

    Zhuang, Leimeng; Taddei, Caterina; Hoekman, Marcel; Leinse, Arne; Heideman, René; van Dijk, Paulus; Roeloffzen, Chris

    2013-11-04

    In this paper, we propose and experimentally demonstrate a novel wideband on-chip photonic modulation transformer for phase-modulated microwave photonic links. The proposed device is able to transform phase-modulated optical signals into intensity-modulated versions (or vice versa) with nearly zero conversion of laser phase noise to intensity noise. It is constructed using waveguide-based ring resonators, which features simple architecture, stable operation, and easy reconfigurability. Beyond the stand-alone functionality, the proposed device can also be integrated with other functional building blocks of photonic integrated circuits (PICs) to create on-chip complex microwave photonic signal processors. As an application example, a PIC consisting of two such modulation transformers and a notch filter has been designed and realized in TriPleX(TM) waveguide technology. The realized device uses a 2 × 2 splitting circuit and 3 ring resonators with a free spectral range of 25 GHz, which are all equipped with continuous tuning elements. The device can perform phase-to-intensity modulation transform and carrier suppression simultaneously, which enables high-performance phase-modulated microwave photonics links (PM-MPLs). Associated with the bias-free and low-complexity advantages of the phase modulators, a single-fiber-span PM-MPL with a RF bandwidth of 12 GHz (3 dB-suppression band 6 to 18 GHz) has been demonstrated comprising the proposed PIC, where the achieved spurious-free dynamic range performance is comparable to that of Class-AB MPLs using low-biased Mach-Zehnder modulators.

  7. Electrochemically Modulated Gas/Liquid Separation Technology for In Situ Resource Utilization Process Streams, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — In this phase I program MicroCell Technologies, LLC (MCT) proposes to demonstrate the feasibility of an electrochemically modulated phase separator for in situ...

  8. On the (Frequency) Modulation of Coupled Oscillator Arrays in Phased Array Beam Control

    Science.gov (United States)

    Pogorzelski, R.; Acorn, J.; Zawadzki, M.

    2000-01-01

    It has been shown that arrays of voltage controlled oscillators coupled to nearest neighbors can be used to produce useful aperture phase distributions for phased array antennas. However, placing information of the transmitted signal requires that the oscillations be modulated.

  9. Efficient and Compact Semiconductor Laser Transmitter Modules, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Continue development of a Compact Transmitter Module (CTM). Modules will be voltage controlled to adjust wavlength using temperature and drive current settings. The...

  10. Zero Cross-Talk Regimes in Dually Modulated Mutually-Coupled Nano-lasers

    International Nuclear Information System (INIS)

    Han, H; Zhang, M J; Wang, Y C; Shore, K A

    2017-01-01

    The modulation properties of dually modulated mutually-coupled nano-lasers have been analyzed using rate equations which include the Purcell cavity-enhanced spontaneous emission factor F and the spontaneous emission coupling factor β . Analysis of the dynamical response of modulated mutually-coupled nano-lasers reveals the existence of regimes of zero cross-talk wherein the response of one nano-laser is not impacted by the dynamics of the other nano-laser. The availability of zero-cross talk regimes is seen to offer opportunities for exploitation in photonic integrated circuits. (paper)

  11. Methodology series module 3: Cross-sectional studies

    Directory of Open Access Journals (Sweden)

    Maninder Singh Setia

    2016-01-01

    Full Text Available Cross-sectional study design is a type of observational study design. In a cross-sectional study, the investigator measures the outcome and the exposures in the study participants at the same time. Unlike in case–control studies (participants selected based on the outcome status or cohort studies (participants selected based on the exposure status, the participants in a cross-sectional study are just selected based on the inclusion and exclusion criteria set for the study. Once the participants have been selected for the study, the investigator follows the study to assess the exposure and the outcomes. Cross-sectional designs are used for population-based surveys and to assess the prevalence of diseases in clinic-based samples. These studies can usually be conducted relatively faster and are inexpensive. They may be conducted either before planning a cohort study or a baseline in a cohort study. These types of designs will give us information about the prevalence of outcomes or exposures; this information will be useful for designing the cohort study. However, since this is a 1-time measurement of exposure and outcome, it is difficult to derive causal relationships from cross-sectional analysis. We can estimate the prevalence of disease in cross-sectional studies. Furthermore, we will also be able to estimate the odds ratios to study the association between exposure and the outcomes in this design.

  12. Methodology Series Module 3: Cross-sectional Studies.

    Science.gov (United States)

    Setia, Maninder Singh

    2016-01-01

    Cross-sectional study design is a type of observational study design. In a cross-sectional study, the investigator measures the outcome and the exposures in the study participants at the same time. Unlike in case-control studies (participants selected based on the outcome status) or cohort studies (participants selected based on the exposure status), the participants in a cross-sectional study are just selected based on the inclusion and exclusion criteria set for the study. Once the participants have been selected for the study, the investigator follows the study to assess the exposure and the outcomes. Cross-sectional designs are used for population-based surveys and to assess the prevalence of diseases in clinic-based samples. These studies can usually be conducted relatively faster and are inexpensive. They may be conducted either before planning a cohort study or a baseline in a cohort study. These types of designs will give us information about the prevalence of outcomes or exposures; this information will be useful for designing the cohort study. However, since this is a 1-time measurement of exposure and outcome, it is difficult to derive causal relationships from cross-sectional analysis. We can estimate the prevalence of disease in cross-sectional studies. Furthermore, we will also be able to estimate the odds ratios to study the association between exposure and the outcomes in this design.

  13. Cognitive digital receiver for burst mode phase modulated radio over fiber links

    DEFF Research Database (Denmark)

    Guerrero Gonzalez, Neil; Zibar, Darko; Tafur Monroy, Idelfonso

    2010-01-01

    A novel cognitive receiver for modulation format recognition with reconfigurable carrier recovery scheme is proposed and experimentally demonstrated for phase modulated radio-over-fibre links. Demodulation of burst-mode mixed modulation formats (PSK and QAM) is demonstrated after 40km...

  14. Self-phase modulation of laser light in laser produced plasma

    International Nuclear Information System (INIS)

    Yamanaka, C.; Yamanaka, T.; Mizui, J.; Yamaguchi, N.

    1975-02-01

    A spectrum broadening due to the self-phase modulation of a laser light was observed in the laser produced deuterium and hydrogen plasma. Qualitative treatments of the density modulation due to the self-focusing process and the modulational instability were discussed. The theoretical estimation of spectrum broadening fairly accorded with the experimental results. (auth.)

  15. Wire Bonding on 2S Modules of the Phase-2 CMS Detector

    CERN Document Server

    AUTHOR|(CDS)2226525; Pooth, Oliver

    The LHC will be upgraded to the HL-LHC in the Long Shutdown 3 starting 2024. This upgrade will increase the collision rate and the overall number of colliding particles requiring high precision particle detectors which are able to cope with much higher radiation doses and numbers of particle interactions per bunch crossing. To fulfill these technical requirements the CMS detector will be upgraded in the so-called Phase-2 Upgrade. Among others the silicon tracking system will be completely replaced by a new system providing a higher acceptance, an improved granularity and the feature to include its tracking information into the level-1 trigger. The new outer-tracker will consist of so called 2S modules consisting of two strip sensors and PS modules with a macro-pixel sensor and a strip sensor. The electrical connection between the strip sensors and the front-end electronics is realized by thin aluminum wire bonds. In this thesis the process of wire bonding is introduced and its implementation in the 2S module ...

  16. Measuring of nonlinearity of dye doped liquid crystals using of self phase modulation effect

    International Nuclear Information System (INIS)

    Abedi, M.; Jafari, A.; Tajalli, H.

    2007-01-01

    Self phase modulation in dye doped liquid crystals has investigated and the nonlinearity of dye doped liquid crystals is measured by this effect. The Self phase modulation effect can be used for producing optical micro rings that have many applications in photonics and laser industries.

  17. Affects of binary and continuous phase modulations on the structure of Bessel beams

    CSIR Research Space (South Africa)

    Dudley, Angela L

    2010-09-01

    Full Text Available The authors implement a novel technique to operate a phase-only spatial light modulator (SLM) in amplitude mode, allowing them to reproduce Durnin’s ring slit on a liquid crystal display (LCD). The affects of binary and continuous phase modulations...

  18. Polarization states encoded by phase modulation for high bit rate quantum key distribution

    International Nuclear Information System (INIS)

    Liu Xiaobao; Tang Zhilie; Liao Changjun; Lu Yiqun; Zhao Feng; Liu Songhao

    2006-01-01

    We present implementation of quantum cryptography with polarization code by wave-guide type phase modulator. At four different low input voltages of the phase modulator, coder encodes pulses into four different polarization states, 45 o , 135 o linearly polarized or right, left circle polarized, while the decoder serves as the complementary polarizers

  19. Understanding of phase modulation in two-level systems through inverse scattering

    International Nuclear Information System (INIS)

    Hasenfeld, A.; Hammes, S.L.; Warren, W.S.

    1988-01-01

    Analytical and numerical calculations describe the effects of shaped radiation pulses on two-level systems in terms of quantum-mechanical scattering. Previous results obtained in the reduced case of amplitude modulation are extended to the general case of simultaneous amplitude and phase modulation. We show that an infinite family of phase- and amplitude-modulated pulses all generate rectangular inversion profiles. Experimental measurements also verify the theoretical analysis

  20. Cross-flow filtration of yeast extract with multi-tubular membrane module and rotating-disk membrane module; Makukaitengata heibanmaku module to tankanjomaku module ni yoru kobo hasaieki no cross flow roka

    Energy Technology Data Exchange (ETDEWEB)

    Matsushita, K.; Shimizu, Y.; Watanabe, a. [Toto Ltd., Kitakyushu (Japan)

    1994-09-15

    A membrane separation experiment was made with multi-tubular membrane module and rotating-disk membrane module to study the cross-flow filtration of yeast extract. The membrane was an alumina precision filtration membrane with 0.15 micron m diameter pores. A multi-tubular membrane which was 19 in number of channels and 0.113{sup 2} in effective membrane area was fitted to the multi-tubular membrane module. A rotating-disk membrane which was 0.071m{sup 2} in effective membrane area was fitted to the rotating-disk membrane module. Judging from the concentration speed and factor, the rotating-disk type is more advantageous in concentrating the suspension than the multi-tubular type. The soluble high-molecular component was more easily filtrated through the rotating-disk type, which is judged attributable to its possible operation at a high flow rate on the membrane surface without necessitating a high-flow rate circulation pump. As compared with the conventional cross-filtration type, the rotating-disk type gives a high permeate flux even at a high concentration factor. 11 refs., 5 figs.

  1. Phase dynamics of a Josephson junction ladder driven by modulated currents

    International Nuclear Information System (INIS)

    Kawaguchi, T.

    2011-01-01

    Phase dynamics of disordered Josephson junction ladders (JJLs) driven by external currents which are spatially and temporally modulated is studied using a numerical simulation based on a random field XY model. This model is considered theoretically as an effective model of JJLs with structural disorder in a magnetic field. The spatiotemporal modulation of external currents causes peculiar dynamical effects of phases in the system under certain conditions, such as the directed motion of phases and the mode-locking in the absence of dc currents. We clarify the details of effects of the spatiotemporal modulation on the phase dynamics.

  2. Performance improvement of coherent free-space optical communication with quadrature phase-shift keying modulation using digital phase estimation.

    Science.gov (United States)

    Li, Xueliang; Geng, Tianwen; Ma, Shuang; Li, Yatian; Gao, Shijie; Wu, Zhiyong

    2017-06-01

    The performance of coherent free-space optical (CFSO) communication with phase modulation is limited by both phase fluctuations and intensity scintillations induced by atmospheric turbulence. To improve the system performance, one effective way is to use digital phase estimation. In this paper, a CFSO communication system with quadrature phase-shift keying modulation is studied. With consideration of the effects of log-normal amplitude fluctuations and Gauss phase fluctuations, a two-stage Mth power carrier phase estimation (CPE) scheme is proposed. The simulation results show that the phase noise can be suppressed greatly by this scheme, and the system symbol error rate performance with the two-stage Mth power CPE can be three orders lower than that of the single-stage Mth power CPE. Therefore, the two-stage CPE we proposed can contribute to the performance improvements of the CFSO communication system and has determinate guidance sense to its actual application.

  3. Phase extraction based on iterative algorithm using five-frame crossed fringes in phase measuring deflectometry

    Science.gov (United States)

    Jin, Chengying; Li, Dahai; Kewei, E.; Li, Mengyang; Chen, Pengyu; Wang, Ruiyang; Xiong, Zhao

    2018-06-01

    In phase measuring deflectometry, two orthogonal sinusoidal fringe patterns are separately projected on the test surface and the distorted fringes reflected by the surface are recorded, each with a sequential phase shift. Then the two components of the local surface gradients are obtained by triangulation. It usually involves some complicated and time-consuming procedures (fringe projection in the orthogonal directions). In addition, the digital light devices (e.g. LCD screen and CCD camera) are not error free. There are quantization errors for each pixel of both LCD and CCD. Therefore, to avoid the complex process and improve the reliability of the phase distribution, a phase extraction algorithm with five-frame crossed fringes is presented in this paper. It is based on a least-squares iterative process. Using the proposed algorithm, phase distributions and phase shift amounts in two orthogonal directions can be simultaneously and successfully determined through an iterative procedure. Both a numerical simulation and a preliminary experiment are conducted to verify the validity and performance of this algorithm. Experimental results obtained by our method are shown, and comparisons between our experimental results and those obtained by the traditional 16-step phase-shifting algorithm and between our experimental results and those measured by the Fizeau interferometer are made.

  4. Nonlinearity and Phase Noise Tolerant 75-110 GHz Signal over Fiber System Using Phase Modulation Technique

    DEFF Research Database (Denmark)

    Deng, Lei; Pang, Xiaodan; Zhang, Xu

    2013-01-01

    We report on the transmission of 8 Gb/s 0 dB PAPR 16QAM-OFDM W-band (75-110 GHz) signals over 22.8km SMF without phase noise compensation by using a phase modulator in the optical heterodyne up-convertor....

  5. Ultracompact electro-optic phase modulator based on III-V-on-silicon microdisk resonator.

    Science.gov (United States)

    Lloret, J; Kumar, R; Sales, S; Ramos, F; Morthier, G; Mechet, P; Spuesens, T; Van Thourhout, D; Olivier, N; Fédéli, J-M; Capmany, J

    2012-06-15

    A novel ultracompact electro-optic phase modulator based on a single 9 μm-diameter III-V microdisk resonator heterogeneously integrated on and coupled to a nanophotonic waveguide is presented. Modulation is enabled by effective index modification through carrier injection. Proof-of-concept implementation involving binary phase shift keying modulation format is assembled. A power imbalance of ∼0.6  dB between both symbols and a modulation rate up to 1.8 Gbps are demonstrated without using any special driving technique.

  6. Heterodyne technique for measuring the amplitude and phase transfer functions of an optical modulator

    DEFF Research Database (Denmark)

    Romstad, Francis Pascal; Birkedal, Dan; Mørk, Jesper

    2002-01-01

    In this letter, we propose a technique based on heterodyne detection for accurately and simultaneously measuring the amplitude and phase transfer functions of an optical modulator. The technique is used to characterize an InGaAsp multiple quantum-well electroabsorption modulator. From the measure...... the measurements we derive the small-signal alpha-parameter and the time-dependent chirp for different operation conditions.......In this letter, we propose a technique based on heterodyne detection for accurately and simultaneously measuring the amplitude and phase transfer functions of an optical modulator. The technique is used to characterize an InGaAsp multiple quantum-well electroabsorption modulator. From...

  7. Cross-layer combining of power control and adaptive modulation with truncated ARQ for cognitive radios

    Institute of Scientific and Technical Information of China (English)

    CHENG Shi-lun; YANG Zhen

    2008-01-01

    To maximize throughput and to satisfy users' requirements in cognitive radios, a cross-layer optimization problem combining adaptive modulation and power control at the physical layer and truncated automatic repeat request at the medium access control layer is proposed. Simulation results show the combination of power control, adaptive modulation, and truncated automatic repeat request can regulate transmitter powers and increase the total throughput effectively.

  8. Black hole in a waveguide: Hawking radiation or self-phase modulation?

    International Nuclear Information System (INIS)

    Smolyaninov, Igor I

    2015-01-01

    Recently it was suggested that Hawking radiation may be observed in a nonlinear electromagnetic waveguide upon propagation of an optical pulse. We show that the spectral characteristics of the Hawking effect in such a waveguide are indistinguishable from the well-known effect of frequency broadening of an optical pulse due to self-phase modulation. Furthermore, we derive an estimate on the critical optical power at which Hawking effect is dominated by the self-phase modulation. It appears that optical experiments reported so far are clearly dominated by self-phase modulation. (paper)

  9. Novel electro-optical phase modulator based on GaInAs/InP modulation-doped quantum-well structures

    DEFF Research Database (Denmark)

    Thirstrup, C.

    1992-01-01

    A novel electro-optical phase modulator working at 1.55 µm is analyzed and proposed. It is shown by a numerical model that in a GaInAs/InP pn-nin-pn multiple-quantum-well waveguide structure, large optical phase modulation can be obtained at small intensity modulation and with improved performance...

  10. Self-Assembling Wireless Autonomous Reconfigurable Modules (SWARM), Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Payload Systems Inc. and the MIT Space Systems Laboratory propose Self-assembling, Wireless, Autonomous, Reconfigurable Modules (SWARM) as an innovative approach to...

  11. LMM Holographic Optical Tweezers (HOT) Module, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to expand the capabilities of the LMM for colloidal and other research by developing a holographic optical tweezers (HOT) module, allowing solid-state...

  12. Discontinuous conduction mode analysis of phase-modulated series ...

    Indian Academy of Sciences (India)

    modulated dc–dc series resonant converter (SRC) operating in discontinuous conduction mode (DCM). The conventional fundamental harmonic approximation technique is extended for a non-ideal series resonant tank to clarify the limitations of ...

  13. Detection and processing of phase modulated optical signals at 40 Gbit/s and beyond

    DEFF Research Database (Denmark)

    Geng, Yan

    the amplitude regeneration capability based on FWM in a highly nonlinear fiber (HNLF). The first reported experimental demonstration of amplitude equalization of 40 Gbit/s RZ-DPSK signals using a 500 m long HNLF is presented. Using four possible phase levels to carry the information, DQPSK allows generation......This thesis addresses demodulation in direct detection systems and signal processing of high speed phase modulated signals in future all-optical wavelength division multiplexing (WDM) communication systems where differential phase shift keying (DPSK) or differential quadrature phase shift keying...... (DQPSK) are used to transport information. All-optical network functionalities -such as optical labeling, wavelength conversion and signal regeneration- are experimentally investigated. Direct detection of phase modulated signals requires phase-to-intensity modulation conversion in a demodulator...

  14. The generation of flat-top beams by complex amplitude modulation with a phase-only spatial light modulator

    CSIR Research Space (South Africa)

    Hendriks, A

    2012-08-01

    Full Text Available amplitude modulation of the light, i.e., in amplitude and phase. We outline the theoretical concept, and then illustrate its use with the example of the laser beam shaping of Gaussian beams into flat-top beams. We quantify the performance of this approach...

  15. Electrical power inverter having a phase modulated, twin-inverter, high frequency link and an energy storage module

    Science.gov (United States)

    Pitel, Ira J.

    1987-02-03

    The present invention provides an electrical power inverter method and apparatus, which includes a high frequency link, for converting DC power into AC power. Generally stated, the apparatus includes a first high frequency module which produces an AC voltage at a first output frequency, and a second high frequency inverter module which produces an AC voltage at a second output frequency that is substantially the same as the first output frequency. The second AC voltage is out of phase with the first AC voltage by a selected angular phase displacement. A mixer mixes the first and second output voltages to produce a high frequency carrier which has a selected base frequency impressed on the sidebands thereof. A rectifier rectifies the carrier, and a filter filters the rectified carrier. An output inverter inverts the filtered carrier to produce an AC line voltage at the selected base frequency. A phase modulator adjusts the relative angular phase displacement between the outputs of the first and second high frequency modules to control the base frequency and magnitude of the AC line voltage.

  16. Electrical power inverter having a phase modulated, twin-inverter, high frequency link and an energy storage module

    Science.gov (United States)

    Pitel, I.J.

    1987-02-03

    The present invention provides an electrical power inverter method and apparatus, which includes a high frequency link, for converting DC power into AC power. Generally stated, the apparatus includes a first high frequency module which produces an AC voltage at a first output frequency, and a second high frequency inverter module which produces an AC voltage at a second output frequency that is substantially the same as the first output frequency. The second AC voltage is out of phase with the first AC voltage by a selected angular phase displacement. A mixer mixes the first and second output voltages to produce a high frequency carrier which has a selected base frequency impressed on the sidebands thereof. A rectifier rectifies the carrier, and a filter filters the rectified carrier. An output inverter inverts the filtered carrier to produce an AC line voltage at the selected base frequency. A phase modulator adjusts the relative angular phase displacement between the outputs of the first and second high frequency modules to control the base frequency and magnitude of the AC line voltage. 19 figs.

  17. The Implications of Encoder/Modulator/ Phased Array Designs for Future Broadband LEO Communications

    Science.gov (United States)

    Vanderaar, Mark; Jensen, Chris A.; Terry, John D.

    1997-01-01

    In this paper we summarize the effects of modulation and channel coding on the design of wide angle scan, broadband, phased army antennas. In the paper we perform several trade studies. First, we investigate the amplifier back-off requirement as a function of variability of modulation envelope. Specifically, we contrast constant and non-constant envelope modulations, as well as single and multiple carrier schemes. Additionally, we address the issues an(f concerns of using pulse shaping filters with the above modulation types. Second, we quantify the effects of beam steering on the quality of data, recovery using selected modulation techniques. In particular, we show that the frequency response of the array introduces intersymbol interference for broadband signals and that the mode of operation for the beam steering controller may introduce additional burst or random errors. Finally, we show that the encoder/modulator design must be performed in conjunction with the phased array antenna design.

  18. Smoothing by spectral dispersion using random phase modulation for inertial confinement fusion

    International Nuclear Information System (INIS)

    Rothenberg, J.E.

    1995-01-01

    Numerical simulations of beam smoothing using random phase modulation and grating dispersion are presented. Spatial spectra of the target illumination show that significantly improved smoothing at low spatial frequency is achieved while maintaining uniform intensity in the laser amplifier

  19. Direct UV written Michelson interferometer for RZ signal generation using phase-to-intensity modulation conversion

    DEFF Research Database (Denmark)

    Peucheret, Christophe; Geng, Yan; Zsigri, Beata

    2005-01-01

    An integrated Michelson delay interferometer structure making use of waveguide gratings as reflective elements is proposed and fabricated by direct ultraviolet writing. Successful return-to-zero alternate-mark-inversion signal generation using phase-to-intensity modulation conversion...

  20. Fast nanoscale heat-flux modulation with phase-change materials

    OpenAIRE

    Van Zwol , Pieter; Joulain , Karl; Ben-Abdallah , Philippe; Greffet , Jean-Jacques; Chevrier , Joël

    2011-01-01

    International audience; We introduce a new concept for electrically controlled heat flux modulation. A flux contrast larger than 10 dB is expected with switching time on the order of tens of nanoseconds. Heat flux modulation is based on the interplay between radiative heat transfer at the nanoscale and phase change materials. Such large contrasts are not obtainable in solids, or in far field. As such this opens up new horizons for temperature modulation and actuation at the nanoscale.

  1. Microwave photonic filters with negative coefficients based on phase inversion in an electro-optic modulator.

    Science.gov (United States)

    Capmany, José; Pastor, Daniel; Martinez, Alfonso; Ortega, Beatriz; Sales, Salvador

    2003-08-15

    We report on a novel technical approach to the implementation of photonic rf filters that is based on the pi phase inversion that a rf modulating signal suffers in an electro-optic Mach-Zehnder modulator, which depends on whether the positive or the negative linear slope of the signal's modulation transfer function is employed. Experimental evidence is provided of the implementation of filters with negative coefficients that shows excellent agreement with results predicted by the theory.

  2. A Voltage Modulated DPC Approach for Three-Phase PWM Rectifier

    DEFF Research Database (Denmark)

    Gui, Yonghao; Li, Mingshen; Lu, Jinghang

    2018-01-01

    In this paper, a voltage modulated direct power control for three-phase pulse-width modulated rectifier is proposed. With the suggested method, the differential equations describing the rectifier dynamics are changing from a linear time-varying system into a linear time-invariant one. In this way...

  3. Phase Modulation for postcompensation of dispersion in 160-Gb/s systems

    DEFF Research Database (Denmark)

    Siahlo, Andrei; Clausen, A. T.; Oxenløwe, Leif Katsuo

    2005-01-01

    Tunable postcompensation of second-order dispersion by sinusoidal phase modulation is realized for a 160-Gb/s optical transmission system. Accumulated dispersions with magnitudes up to 4 ps/nm are compensated in the receiver end.......Tunable postcompensation of second-order dispersion by sinusoidal phase modulation is realized for a 160-Gb/s optical transmission system. Accumulated dispersions with magnitudes up to 4 ps/nm are compensated in the receiver end....

  4. Experimental Demonstration of Capacity-Achieving Phase-Shifted Superposition Modulation

    DEFF Research Database (Denmark)

    Estaran Tolosa, Jose Manuel; Zibar, Darko; Caballero Jambrina, Antonio

    2013-01-01

    We report on the first experimental demonstration of phase-shifted superposition modulation (PSM) for optical links. Successful demodulation and decoding is obtained after 240 km transmission for 16-, 32- and 64-PSM.......We report on the first experimental demonstration of phase-shifted superposition modulation (PSM) for optical links. Successful demodulation and decoding is obtained after 240 km transmission for 16-, 32- and 64-PSM....

  5. Brillouin suppression in a fiber optical parametric amplifier by combining temperature distribution and phase modulation

    DEFF Research Database (Denmark)

    Lorenzen, Michael Rodas; Noordegraaf, Danny; Nielsen, Carsten Vandel

    2008-01-01

    We demonstrate an increased gain in optical parametric amplier through suppression of stimulated Brillouin scattering by applying a temperature distribution along the fiber resulting in a reduction of the required phase modulation.......We demonstrate an increased gain in optical parametric amplier through suppression of stimulated Brillouin scattering by applying a temperature distribution along the fiber resulting in a reduction of the required phase modulation....

  6. Proposal and design of phase-modulated fiber gratings in transmission for pulse shaping.

    Science.gov (United States)

    Preciado, Miguel A; Shu, Xuewen; Sugden, Kate

    2013-01-01

    An approach to pulse shaping using a phase-modulated fiber Bragg grating (FBG) in transmission is proposed and designed. We show that phase-modulated FBGs can provide transmission responses suitable for pulse shaping applications, offering important technological feasibility benefits, since the coupling strength remains basically uniform in the grating. Moreover, this approach retains the substantial advantages of FBGs in transmission, such as optimum energy efficiency, no requirement for an optical circulator, and robustness against fabrication errors.

  7. Kinetic theory of cross-modulation in a weakly ionized plasma

    International Nuclear Information System (INIS)

    Garrett, A.J.M.

    1991-01-01

    Cross-modulation in plasma is an electromagnetic wave interaction in which the modulation of one 'disturbing' wave is imposed nonlinearly on the transport properties of the medium, and thence onto a second, 'wanted' wave propagating linearly through it. This analysis is restricted to weakly ionized plasma with allowance for ambient magnetic field, as in the lower ionosphere. A kinetic description is used, based on the Boltzmann equation for the electrons, with electron-molecule collisions described by Boltzmann's collision integral. Because of the small mass ratio this simplifies to a differential form. There is no cross-modulation if the collision frequency is independent of collision speed, when contributions from all parts of velocity space cancel. (author)

  8. Basis for calculating cross sections for nuclear magnetic resonance spin-modulated polarized neutron scattering.

    Science.gov (United States)

    Kotlarchyk, Michael; Thurston, George M

    2016-12-28

    In this work we study the potential for utilizing the scattering of polarized neutrons from nuclei whose spin has been modulated using nuclear magnetic resonance (NMR). From first principles, we present an in-depth development of the differential scattering cross sections that would arise in such measurements from a hypothetical target system containing nuclei with non-zero spins. In particular, we investigate the modulation of the polarized scattering cross sections following the application of radio frequency pulses that impart initial transverse rotations to selected sets of spin-1/2 nuclei. The long-term aim is to provide a foundational treatment of the scattering cross section associated with enhancing scattering signals from selected nuclei using NMR techniques, thus employing minimal chemical or isotopic alterations, so as to advance the knowledge of macromolecular or liquid structure.

  9. Verification of the cross-section and depletion chain processing module of DRAGON 3.06

    International Nuclear Information System (INIS)

    Chambon, R.; Marleau, G.; Zkiek, A.

    2008-01-01

    In this paper we present a verification of the module of the lattice code DRAGON 3.06 used for processing microscopic cross-section libraries, including their associated depletion chain. This verification is performed by reprogramming the capabilities of DRAGON in another language (MATLAB) and testing them on different problems typical of the CANDU reactor. The verification procedure consists in first programming MATLAB m-files to read the different cross section libraries in ASCII format and to compute the reference cross-sections and depletion chains. The same information is also recovered from the output files of DRAGON (using different m-files) and the resulting cross sections and depletion chain are compared with the reference library, the differences being evaluated and tabulated. The results show that the cross-section calculations and the depletion chains are correctly processed in version 3.06 of DRAGON. (author)

  10. A review of single-phase grid-connected inverters for photovoltaic modules

    DEFF Research Database (Denmark)

    Kjaer, Soren Baekhoej; Pedersen, John Kim; Blaabjerg, Frede

    2005-01-01

    -phase grid; 3) whether they utilizes a transformer (either line or high frequency) or not; and 4) the type of grid-connected power stage. Various inverter topologies are presented, compared, and evaluated against demands, lifetime, component ratings, and cost. Finally, some of the topologies are pointed out......This review focuses on inverter technologies for connecting photovoltaic (PV) modules to a single-phase grid. The inverters are categorized into four classifications: 1) the number of power processing stages in cascade; 2) the type of power decoupling between the PV module(s) and the single...

  11. Color image cryptosystem using Fresnel diffraction and phase modulation in an expanded fractional Fourier transform domain

    Science.gov (United States)

    Chen, Hang; Liu, Zhengjun; Chen, Qi; Blondel, Walter; Varis, Pierre

    2018-05-01

    In this letter, what we believe is a new technique for optical color image encryption by using Fresnel diffraction and a phase modulation in an extended fractional Fourier transform domain is proposed. Different from the RGB component separation based method, the color image is converted into one component by improved Chirikov mapping. The encryption system is addressed with Fresnel diffraction and phase modulation. A pair of lenses is placed into the fractional Fourier transform system for the modulation of beam propagation. The structure parameters of the optical system and parameters in Chirikov mapping serve as extra keys. Some numerical simulations are given to test the validity of the proposed cryptosystem.

  12. Invisible anti-cloak with elliptic cross section using phase complement

    International Nuclear Information System (INIS)

    Yang Yu-Qi; Zhang Min; Yue Jian-Xiang

    2011-01-01

    Based on the theory of phase complement, an anti-cloak with circular cross section can be made invisible to an object outside its domain. As the cloak with elliptic cross section is more effective to make objects invisible than that with circular cross section, a scaled coordinate system is proposed to design equivalent materials of invisible anti-cloak with elliptic cross section using phase complement. The cloaks with conventional dielectric and double negative parameters are both simulated with the geometrical transformations. The results show that the cloak with elliptic cross section through phase complement can effectively hide the outside objects. (classical areas of phenomenology)

  13. Phase-ambiguity resolution for QPSK modulation systems. Part 2: A method to resolve offset QPSK

    Science.gov (United States)

    Nguyen, Tien Manh

    1989-01-01

    Part 2 presents a new method to resolve the phase-ambiguity for Offset QPSK modulation systems. When an Offset Quaternary Phase-Shift-Keyed (OQPSK) communications link is utilized, the phase ambiguity of the reference carrier must be resolved. At the transmitter, two different unique words are separately modulated onto the quadrature carriers. At the receiver, the recovered carrier may have one of four possible phases, 0, 90, 180, or 270 degrees, referenced to the nominally correct phase. The IF portion of the channel may cause a phase-sense reversal, i.e., a reversal in the direction of phase rotation for a specified bit pattern. Hence, eight possible phase relationships (the so-called eight ambiguous phase conditions) between input and output of the demodulator must be resolved. Using the In-phase (I)/Quadrature (Q) channel reversal correcting property of an OQPSK Costas loop with integrated symbol synchronization, four ambiguous phase conditions are eliminated. Thus, only four possible ambiguous phase conditions remain. The errors caused by the remaining ambiguous phase conditions can be corrected by monitoring and detecting the polarity of the two unique words. The correction of the unique word polarities results in the complete phase-ambiguity resolution for the OQPSK system.

  14. Phase modulation due to crystal diffraction by ptychographic imaging

    Science.gov (United States)

    Civita, M.; Diaz, A.; Bean, R. J.; Shabalin, A. G.; Gorobtsov, O. Yu.; Vartanyants, I. A.; Robinson, I. K.

    2018-03-01

    Solving the phase problem in x-ray crystallography has occupied a considerable scientific effort in the 20th century and led to great advances in structural science. Here we use x-ray ptychography to demonstrate an interference method which measures the phase of the beam transmitted through a crystal, relative to the incoming beam, when diffraction takes place. The observed phase change of the direct beam through a small gold crystal is found to agree with both a quasikinematical model and full dynamical theories of diffraction. Our discovery of a diffraction contrast mechanism will enhance the interpretation of data obtained from crystalline samples using the ptychography method, which provides some of the most accurate x-ray phase-contrast images.

  15. Electrically and spatially controllable PDLC phase gratings for diffraction and modulation of laser beams

    Energy Technology Data Exchange (ETDEWEB)

    Hadjichristov, Georgi B., E-mail: georgibh@issp.bas.bg [Laboratory of Optics and Spectroscopy, Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd., BG-1784 Sofia (Bulgaria); Marinov, Yordan G.; Petrov, Alexander G. [Laboratory of Biomolecular Layers, Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd., BG-1784 Sofia, Bulgaria (Bulgaria)

    2016-03-25

    We present a study on electrically- and spatially-controllable laser beam diffraction, electrooptic (EO) phase modulation, as well as amplitude-frequency EO modulation by single-layer microscale polymer-dispersed liquid crystal (PDLC) phase gratings (PDLC SLPGs) of interest for device applications. PDLC SLPGs were produced from nematic liquid crystal (LC) E7 in photo-curable NOA65 polymer. The wedge-formed PDLC SLPGs have a continuously variable thickness (2–25 µm). They contain LC droplets of diameters twice as the layer thickness, with a linear-gradient size distribution along the wedge. By applying alternating-current (AC) electric field, the PDLC SLPGs produce efficient: (i) diffraction splitting of transmitted laser beams; (ii) spatial redistribution of diffracted light intensity; (iii) optical phase modulation; (iv) amplitude-frequency modulation, all controllable by the driven AC field and the droplet size gradient.

  16. Statistics of errors in fibre communication lines with a phase-modulation format and optical phase conjugation

    International Nuclear Information System (INIS)

    Shapiro, Elena G; Fedoruk, Mikhail P

    2011-01-01

    Analytical formulas are derived to approximate the probability density functions of 'zero' and 'one' bits in a linear communication channel with a binary format of optical signal phase modulation. Direct numerical simulation of the propagation of optical pulses in a communication line with optical phase conjugation is performed. The results of the numerical simulation are in good agreement with the analytical approximation. (fibreoptic communication lines)

  17. Iodine-frequency-stabilized laser diode and displacement-measuring interferometer based on sinusoidal phase modulation

    Science.gov (United States)

    Duong, Quang Anh; Vu, Thanh Tung; Higuchi, Masato; Wei, Dong; Aketagawa, Masato

    2018-06-01

    We propose a sinusoidal phase modulation method to achieve both the frequency stabilization of an external-cavity laser diode (ECLD) to an 127I2 saturated absorption transition near 633 nm and displacement measurement using a Mach–Zehnder interferometer. First, the frequency of the ECLD is stabilized to the b 21 hyperfine component of the P(33) 6-3 transition of 127I2 by combining sinusoidal phase modulation by an electro-optic modulator and frequency modulation spectroscopy by chopping the pump beam using an acousto-optic modulator. Even though a small modulation index of m  =  3.768 rad is utilized, a relative frequency stability of 10‑11 order is obtained over a sampling time of 400 s. Secondly, the frequency-stabilized ECLD is applied as a light source to a Mach–Zehnder interferometer. From the two consecutive modulation harmonics (second and third orders) involved in the interferometer signal, the displacement of the moving mirror is determined for four optical path differences (L 0  =  100, 200, 500, and 1000 mm). The measured modulation indexes for the four optical path differences coincide with the designated value (3.768 rad) within 0.5%. Compared with the sinusoidal frequency modulation Michelson interferometer (Vu et al 2016 Meas. Sci. Technol. 27 105201) which was demonstrated by some of the same authors of this paper, the phase modulation Mach–Zhender interferometer could fix the modulation index to a constant value for the four optical path differences. In this report, we discuss the measurement principle, experimental system, and results.

  18. Phase-ambiguity resolution for QPSK modulation systems. Part 1: A review

    Science.gov (United States)

    Nguyen, Tien Manh

    1989-01-01

    Part 1 reviews the current phase-ambiguity resolution techniques for QPSK coherent modulation systems. Here, those known and published methods of resolving phase ambiguity for QPSK with and without Forward-Error-Correcting (FEC) are discussed. The necessary background is provided for a complete understanding of the second part where a new technique will be discussed. An appropriate technique to the Consultative Committee for Space Data Systems (CCSDS) is recommended for consideration in future standards on phase-ambiguity resolution for QPSK coherent modulation systems.

  19. Large resistivity modulation in mixed-phase metallic systems.

    Science.gov (United States)

    Lee, Yeonbae; Liu, Z Q; Heron, J T; Clarkson, J D; Hong, J; Ko, C; Biegalski, M D; Aschauer, U; Hsu, S L; Nowakowski, M E; Wu, J; Christen, H M; Salahuddin, S; Bokor, J B; Spaldin, N A; Schlom, D G; Ramesh, R

    2015-01-07

    In numerous systems, giant physical responses have been discovered when two phases coexist; for example, near a phase transition. An intermetallic FeRh system undergoes a first-order antiferromagnetic to ferromagnetic transition above room temperature and shows two-phase coexistence near the transition. Here we have investigated the effect of an electric field to FeRh/PMN-PT heterostructures and report 8% change in the electrical resistivity of FeRh films. Such a 'giant' electroresistance (GER) response is striking in metallic systems, in which external electric fields are screened, and thus only weakly influence the carrier concentrations and mobilities. We show that our FeRh films comprise coexisting ferromagnetic and antiferromagnetic phases with different resistivities and the origin of the GER effect is the strain-mediated change in their relative proportions. The observed behaviour is reminiscent of colossal magnetoresistance in perovskite manganites and illustrates the role of mixed-phase coexistence in achieving large changes in physical properties with low-energy external perturbation.

  20. A dynamic plasmonic manipulation technique assisted by phase modulation of an incident optical vortex beam

    International Nuclear Information System (INIS)

    Yuan, G H; Wang, Q; Tan, P S; Lin, J; Yuan, X-C

    2012-01-01

    A novel phase modulation method for dynamic manipulation of surface plasmon polaritons (SPPs) with a phase engineered optical vortex (OV) beam illuminating on nanoslits is experimentally demonstrated. Because of the unique helical phase carried by an OV beam, dynamic control of SPP multiple focusing and standing wave generation is realized by changing the OV beam’s topological charge constituent with the help of a liquid-crystal spatial light modulator. Measurement of SPP distributions with near-field scanning optical microscopy showed an excellent agreement with numerical predictions. The proposed phase modulation technique for manipulating SPPs features has seemingly dynamic and reconfigurable advantages, with profound potential for development of SPP coupling, routing, multiplexing and high-resolution imaging devices on plasmonic chips. (paper)

  1. Pattern manipulation via on-chip phase modulation between orbital angular momentum beams

    International Nuclear Information System (INIS)

    Li, Huanlu; Strain, Michael J.; Meriggi, Laura; Sorel, Marc; Chen, Lifeng; Zhu, Jiangbo; Cicek, Kenan; Wang, Jianwei; Thompson, Mark G.; Cai, Xinlun; Yu, Siyuan

    2015-01-01

    An integrated approach to thermal modulation of relative phase between two optical vortices with opposite chirality has been demonstrated on a silicon-on-insulator substrate. The device consists of a silicon-integrated optical vortex emitter and a phase controlled 3 dB coupler. The relative phase between two optical vortices can be actively modulated on chip by applying a voltage on the integrated heater. The phase shift is shown to be linearly proportional to applied electrical power, and the rotation angle of the interference pattern is observed to be inversely proportional to topological charge. This scheme can be used in lab-on-chip, communications and sensing applications. It can be intentionally implemented with other modulation elements to achieve more complicated applications

  2. Pattern manipulation via on-chip phase modulation between orbital angular momentum beams

    Energy Technology Data Exchange (ETDEWEB)

    Li, Huanlu [Department of Electrical and Electronic Engineering, University of Bristol, University Walk, Bristol BS8 1TR (United Kingdom); School of Engineering, University of Glasgow, Rankine Building, Oakfield Avenue, Glasgow G12 8LP (United Kingdom); Strain, Michael J. [School of Engineering, University of Glasgow, Rankine Building, Oakfield Avenue, Glasgow G12 8LP (United Kingdom); Wolfson Centre, Institute of Photonics, University of Strathclyde, 106 Rottenrow East, Glasgow G4 0NW (United Kingdom); Meriggi, Laura; Sorel, Marc [School of Engineering, University of Glasgow, Rankine Building, Oakfield Avenue, Glasgow G12 8LP (United Kingdom); Chen, Lifeng; Zhu, Jiangbo; Cicek, Kenan [Department of Electrical and Electronic Engineering, University of Bristol, University Walk, Bristol BS8 1TR (United Kingdom); Wang, Jianwei; Thompson, Mark G. [Centre for Quantum Photonics, H. H. Wills Physics Laboratory and Department of Electrical and Electronic Engineering, University of Bristol, Bristol BS8 1UB (United Kingdom); Cai, Xinlun, E-mail: caixlun5@mail.sysu.edu.cn [Centre for Quantum Photonics, H. H. Wills Physics Laboratory and Department of Electrical and Electronic Engineering, University of Bristol, Bristol BS8 1UB (United Kingdom); State Key Laboratory of Optoelectronic Materials and Technologies and School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Yu, Siyuan, E-mail: s.yu@bristol.ac.uk [Department of Electrical and Electronic Engineering, University of Bristol, University Walk, Bristol BS8 1TR (United Kingdom); State Key Laboratory of Optoelectronic Materials and Technologies and School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China)

    2015-08-03

    An integrated approach to thermal modulation of relative phase between two optical vortices with opposite chirality has been demonstrated on a silicon-on-insulator substrate. The device consists of a silicon-integrated optical vortex emitter and a phase controlled 3 dB coupler. The relative phase between two optical vortices can be actively modulated on chip by applying a voltage on the integrated heater. The phase shift is shown to be linearly proportional to applied electrical power, and the rotation angle of the interference pattern is observed to be inversely proportional to topological charge. This scheme can be used in lab-on-chip, communications and sensing applications. It can be intentionally implemented with other modulation elements to achieve more complicated applications.

  3. Finding binaries from phase modulation of pulsating stars with Kepler

    Science.gov (United States)

    Shibahashi, Hiromoto; Murphy, Simon; Bedding, Tim

    2017-09-01

    Binary orbital motion causes a periodic variation in the path length travelled by light emitted from a star towards us. Hence, if the star is pulsating, the observed phase of the pulsation varies over the orbit. Conversely, once we have observed such phase variation, we can extract information about the binary orbit from photometry alone. Continuous and precise space-based photometry has made it possible to measure these light travel time effects on the pulsating stars in binary systems. This opens up a new way of finding unseen brown dwarfs, planets, or massive compact stellar remnants: neutron stars and black holes.

  4. Characteristics of phase-averaged equations for modulated wave groups

    NARCIS (Netherlands)

    Klopman, G.; Petit, H.A.H.; Battjes, J.A.

    2000-01-01

    The project concerns the influence of long waves on coastal morphology. The modelling of the combined motion of the long waves and short waves in the horizontal plane is done by phase-averaging over the short wave motion and using intra-wave modelling for the long waves, see e.g. Roelvink (1993).

  5. Spontaneous phase transitions in magnetic films with a modulated structure

    International Nuclear Information System (INIS)

    Arzamastseva, G. V.; Evtikhov, M. G.; Lisovskii, F. V.; Mansvetova, E. G.

    2011-01-01

    The influence of monoperiodic and biperiodic bias fields on the nucleation of domain structures in quasi-uniaxial magnetic films near the Curie point has been studied experimentally. The main types of observed nonuniform magnetic moment distributions have been established and chains of a devil’s staircase phase transitions are shown to be realized when the films are slowly cooled.

  6. Safety effects of exclusive and concurrent signal phasing for pedestrian crossing.

    Science.gov (United States)

    Zhang, Yaohua; Mamun, Sha A; Ivan, John N; Ravishanker, Nalini; Haque, Khademul

    2015-10-01

    This paper describes the estimation of pedestrian crash count and vehicle interaction severity prediction models for a sample of signalized intersections in Connecticut with either concurrent or exclusive pedestrian phasing. With concurrent phasing, pedestrians cross at the same time as motor vehicle traffic in the same direction receives a green phase, while with exclusive phasing, pedestrians cross during their own phase when all motor vehicle traffic on all approaches is stopped. Pedestrians crossing at each intersection were observed and classified according to the severity of interactions with motor vehicles. Observation intersections were selected to represent both types of signal phasing while controlling for other physical characteristics. In the nonlinear mixed models for interaction severity, pedestrians crossing on the walk signal at an exclusive signal experienced lower interaction severity compared to those crossing on the green light with concurrent phasing; however, pedestrians crossing on a green light where an exclusive phase was available experienced higher interaction severity. Intersections with concurrent phasing have fewer total pedestrian crashes than those with exclusive phasing but more crashes at higher severity levels. It is recommended that exclusive pedestrian phasing only be used at locations where pedestrians are more likely to comply. Copyright © 2015. Published by Elsevier Ltd.

  7. Multilevel photonic modules for millimeter-wave phased-array antennas

    Science.gov (United States)

    Paolella, Arthur C.; Bauerle, Athena; Joshi, Abhay M.; Wright, James G.; Coryell, Louis A.

    2000-09-01

    Millimeter wave phased array systems have antenna element sizes and spacings similar to MMIC chip dimensions by virtue of the operating wavelength. Designing modules in traditional planar packaing techniques are therefore difficult to implement. An advantageous way to maintain a small module footprint compatible with Ka-Band and high frequency systems is to take advantage of two leading edge technologies, opto- electronic integrated circuits (OEICs) and multilevel packaging technology. Under a Phase II SBIR these technologies are combined to form photonic modules for optically controlled millimeter wave phased array antennas. The proposed module, consisting of an OEIC integrated with a planar antenna array will operate on the 40GHz region. The OEIC consists of an InP based dual-depletion PIN photodetector and distributed amplifier. The multi-level module will be fabricated using an enhanced circuit processing thick film process. Since the modules are batch fabricated using an enhanced circuit processing thick film process. Since the modules are batch fabricated, using standard commercial processes, it has the potential to be low cost while maintaining high performance, impacting both military and commercial communications systems.

  8. POLIDENT: A Module for Generating Continuous-Energy Cross Sections from ENDF Resonance Data

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, M.E.; Greene, N.M.

    2000-12-01

    POLIDENT (Point Libraries of Data from ENDF/B Tapes) is an AMPX module that accesses the resonance parameters from File 2 of an ENDF/B library and constructs the continuous-energy cross sections in the resonance energy region. The cross sections in the resonance range are subsequently combined with the File 3 background data to construct the cross-section representation over the complete energy range. POLIDENT has the capability to process all resonance reactions that are identified in File 2 of the ENDF/B library. In addition, the code has the capability to process the single- and multi-level Breit-Wigner, Reich-Moore and Adler-Adler resonance formalisms that are identified in File 2. POLIDENT uses a robust energy-mesh-generation scheme that determines the minimum, maximum and points of inflection in the cross-section function in the resolved-resonance region. Furthermore, POLIDENT processes all continuous-energy cross-section reactions that are identified in File 3 of the ENDF/B library and outputs all reactions in an ENDF/B TAB1 format that can be accessed by other AMPX modules.

  9. Wind-forced modulations in crossing sea states over infinite depth water

    Science.gov (United States)

    Debsarma, Suma; Senapati, Sudipta; Das, K. P.

    2014-09-01

    The present work is motivated by the work of Leblanc ["Amplification of nonlinear surface waves by wind," Phys. Fluids 19, 101705 (2007)] which showed that Stokes waves grow super exponentially under fair wind as a result of modulational instability. Here, we have studied the effect of wind in a situation of crossing sea states characterized by two obliquely propagating wave systems in deep water. It is found that the wind-forced uniform wave solution in crossing seas grows explosively with a super-exponential growth rate even under a steady horizontal wind flow. This is an important piece of information in the context of the formation of freak waves.

  10. Development of sine/cosine coil based on cross-section modulation

    International Nuclear Information System (INIS)

    Harada, Takahiro; Kondoh, Junji; Tsuji-Iio, Shunji; Shimada, Ryuichi

    1996-01-01

    New type sine and cosine coils whose areas of cross sections vary as sine and cosine are proposed. The measurements of current position by the new coils showed their availability. Traditional sine or cosine coil is wound with a pitch which varies as sine or cosine. However these coils have a problem of manufacturing, i.e. it is not easy to wind wire exactly with a pitch of sine or cosine. This new modulation, i.e. varying cross section, provides handy and accurate measurements of the current position. (author)

  11. Fuzzy Logic Controlled Solar Module for Driving Three- Phase Induction Motor

    Science.gov (United States)

    Afiqah Zainal, Nurul; Sooi Tat, Chan; Ajisman

    2016-02-01

    Renewable energy produced by solar module gives advantages for generated three- phase induction motor in remote area. But, solar module's ou tput is uncertain and complex. Fuzzy logic controller is one of controllers that can handle non-linear system and maximum power of solar module. Fuzzy logic controller used for Maximum Power Point Tracking (MPPT) technique to control Pulse-Width Modulation (PWM) for switching power electronics circuit. DC-DC boost converter used to boost up photovoltaic voltage to desired output and supply voltage source inverter which controlled by three-phase PWM generated by microcontroller. IGBT switched Voltage source inverter (VSI) produced alternating current (AC) voltage from direct current (DC) source to control speed of three-phase induction motor from boost converter output. Results showed that, the output power of solar module is optimized and controlled by using fuzzy logic controller. Besides that, the three-phase induction motor can be drive and control using VSI switching by the PWM signal generated by the fuzzy logic controller. This concluded that the non-linear system can be controlled and used in driving three-phase induction motor.

  12. Fuzzy Logic Controlled Solar Module for Driving Three- Phase Induction Motor

    International Nuclear Information System (INIS)

    Zainal, Nurul Afiqah; Tat, Chan Sooi; Ajisman

    2016-01-01

    Renewable energy produced by solar module gives advantages for generated three- phase induction motor in remote area. But, solar module's output is uncertain and complex. Fuzzy logic controller is one of controllers that can handle non-linear system and maximum power of solar module. Fuzzy logic controller used for Maximum Power Point Tracking (MPPT) technique to control Pulse-Width Modulation (PWM) for switching power electronics circuit. DC-DC boost converter used to boost up photovoltaic voltage to desired output and supply voltage source inverter which controlled by three-phase PWM generated by microcontroller. IGBT switched Voltage source inverter (VSI) produced alternating current (AC) voltage from direct current (DC) source to control speed of three-phase induction motor from boost converter output. Results showed that, the output power of solar module is optimized and controlled by using fuzzy logic controller. Besides that, the three-phase induction motor can be drive and control using VSI switching by the PWM signal generated by the fuzzy logic controller. This concluded that the non-linear system can be controlled and used in driving three-phase induction motor. (paper)

  13. Clock domain crossing modules for OCP-style read/write interfaces

    DEFF Research Database (Denmark)

    Herlev, Mathias; Sparsø, Jens

    The open core protocol (OCP) is an openly licensed, configurable, and scalable interface protocol for on-chip subsystem communications. The protocol defines read and write transactions from a master towards a slave across a point-to-point connection and the protocol assumes a single common clock....... This paper presents the design of two OCP clock domain crossing interface modules, that can be used to construct systems with multiple clock domains. One module (called OCPio) supports a single word read-write interface and the other module (called OCPburst) supports a four word burst read-write interface......-style read-write transaction interfaces. An OCP interface typically has control signals related to both the master issuing a read or write request and the slave producing a response. If all these control signals are passed across the clock domain boundary and synchronized it may add significant latency...

  14. ANALYSIS OF SEEING-INDUCED POLARIZATION CROSS-TALK AND MODULATION SCHEME PERFORMANCE

    International Nuclear Information System (INIS)

    Casini, R.; De Wijn, A. G.; Judge, P. G.

    2012-01-01

    We analyze the generation of polarization cross-talk in Stokes polarimeters by atmospheric seeing, and its effects on the noise statistics of spectropolarimetric measurements for both single-beam and dual-beam instruments. We investigate the time evolution of seeing-induced correlations between different states of one modulation cycle and compare the response to these correlations of two popular polarization modulation schemes in a dual-beam system. Extension of the formalism to encompass an arbitrary number of modulation cycles enables us to compare our results with earlier work. Even though we discuss examples pertinent to solar physics, the general treatment of the subject and its fundamental results might be useful to a wider community.

  15. Experimental Results on the Level Crossing Intervals of the Phase of Sine Wave Plus Noise

    Science.gov (United States)

    Youssef, Neji; Munakata, Tsutomu; Mimaki, Tadashi

    1993-03-01

    Experimental study was made on the level crossing intervals of a phase process of a sine wave plus narrow-band Gaussian noise. Since successive level crossings of phase do not necessarily occur alternately in the upward and downward direction due to the phase jump beyond 2π, the usual definitions of the probability densities of the level crossing intervals for continuous random processes are not applicable in the case of the phase process. Therefore, the probability densities of level crossing intervals of phase process are newly defined. Measurements of these densities were performed for noise having lowpass spectra of Gaussian and 7th order Butterworth types. Results are given for various values of the signal-to-noise power ratio and of the crossing level, and compared with corresponding approximation developed under the assumption of quasi-independence. The validity of the assumption depends on the spectrum shape of the noise.

  16. Hybrid Modulation of Bidirectional Three-Phase Dual-Active-Bridge DC Converters for Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Yen-Ching Wang

    2016-06-01

    Full Text Available Bidirectional power converters for electric vehicles (EVs have received much attention recently, due to either grid-supporting requirements or emergent power supplies. This paper proposes a hybrid modulation of the three-phase dual-active bridge (3ΦDAB converter for EV charging systems. The designed hybrid modulation allows the converter to switch its modulation between phase-shifted and trapezoidal modes to increase the conversion efficiency, even under light-load conditions. The mode transition is realized in a real-time manner according to the charging or discharging current. The operation principle of the converter is analyzed in different modes and thus design considerations of the modulation are derived. A lab-scaled prototype circuit with a 48V/20Ah LiFePO4 battery is established to validate the feasibility and effectiveness.

  17. Chimera and modulated drift states in a ring of nonlocally coupled oscillators with heterogeneous phase lags

    Science.gov (United States)

    Choe, Chol-Ung; Kim, Ryong-Son; Ri, Ji-Song

    2017-09-01

    We consider a ring of phase oscillators with nonlocal coupling strength and heterogeneous phase lags. We analyze the effects of heterogeneity in the phase lags on the existence and stability of a variety of steady states. A nonlocal coupling with heterogeneous phase lags that allows the system to be solved analytically is suggested and the stability of solutions along the Ott-Antonsen invariant manifold is explored. We present a complete bifurcation diagram for stationary patterns including the uniform drift and modulated drift states as well as chimera state, which reveals that the stable modulated drift state and a continuum of metastable drift states could occur due to the heterogeneity of the phase lags. We verify our theoretical results using the direct numerical simulations of the model system.

  18. Effects of nonlinear phase modulation on Bragg scattering in the low-conversion regime

    DEFF Research Database (Denmark)

    Andersen, Lasse Mejling; Cargill, D. S.; McKinstrie, C. J.

    2012-01-01

    In this paper, we consider the effects of nonlinear phase modulation on frequency conversion by four-wave mixing (Bragg scattering) in the low-conversion regime. We derive the Green functions for this process using the time-domain collision method, for partial collisions, in which the four fields...... interact at the beginning or the end of the fiber, and complete collisions, in which the four fields interact at the midpoint of the fiber. If the Green function is separable, there is only one output Schmidt mode, which is free from temporal entanglement. We find that nonlinear phase modulation always...... chirps the input and output Schmidt modes and renders the Green function formally nonseparable. However, by pre-chirping the pumps, one can reduce the chirps of the Schmidt modes and enable approximate separability. Thus, even in the presence of nonlinear phase modulation, frequency conversion...

  19. A vector modulated three-phase four-quadrant rectifier - Application to a dc motor drive

    Energy Technology Data Exchange (ETDEWEB)

    Jussila, Matti; Salo, Mika; Kaehkoenen, Lauri; Tuusa, Heikki

    2004-07-01

    This paper introduces a theory for a space vector modulation of a three-phase four-quadrant PWM rectifier (FQR). The presented vector modulation method is simple to realize with a microcontroller and it replaces the conventional modulation methods based on the analog technology. The FQR may be used to supply directly a dc load, e.g. a dc machine. The vector modulated FQR is tested in simulations supplying a 4.5 kW dc motor. The simulations show the benefits of the vector modulated FQR against thyristor converters: the supply currents are sinusoidal and the displacement power factor of the supply can be controlled. Furthermore the load current is smooth. (author)

  20. A Compact QPSK Modulator with Low Amplitude and Phase Imbalance for Remote Sensing Applications

    KAUST Repository

    Ghaffar, Farhan Abdul

    2012-09-30

    A new, compact and wide-band Quadrature Phase Shift Keying (QPSK) modulator is presented for remote sensing applications. The microstrip-based modulator employs quadrature hybrid coupler, Wilkinson divider, rat race coupler and GaAs MESFET switches. It is designed to be part of an X band remote sensing transmitter with a center frequency of 8.25GHz. The fabricated module demonstrates the lowest reported amplitude and phase imbalances (0.1dB and 0.4° respectively) around its center frequency. The modulation, tested up to 160 Mbps data rate, displays carrier suppression greater than 30 dB. With negligible DC power consumption and low insertion loss, it operates for a wide bandwidth of 3 GHz (7-10 GHz). The effect of amplitude and phase imbalance is investigated on the performance of the modulator. Finally, a transmitter employing this modulator exhibits an excellent overall Error Vector Magnitude (EVM) of around 8 % that is considerably low as compared to the typically obtained values for such transmitters.

  1. A Compact QPSK Modulator with Low Amplitude and Phase Imbalance for Remote Sensing Applications

    KAUST Repository

    Ghaffar, Farhan Abdul; Al-Naffouri, Tareq Y.; Mobeen, M. Kashan; Salama, Khaled N.; Shamim, Atif

    2012-01-01

    A new, compact and wide-band Quadrature Phase Shift Keying (QPSK) modulator is presented for remote sensing applications. The microstrip-based modulator employs quadrature hybrid coupler, Wilkinson divider, rat race coupler and GaAs MESFET switches. It is designed to be part of an X band remote sensing transmitter with a center frequency of 8.25GHz. The fabricated module demonstrates the lowest reported amplitude and phase imbalances (0.1dB and 0.4° respectively) around its center frequency. The modulation, tested up to 160 Mbps data rate, displays carrier suppression greater than 30 dB. With negligible DC power consumption and low insertion loss, it operates for a wide bandwidth of 3 GHz (7-10 GHz). The effect of amplitude and phase imbalance is investigated on the performance of the modulator. Finally, a transmitter employing this modulator exhibits an excellent overall Error Vector Magnitude (EVM) of around 8 % that is considerably low as compared to the typically obtained values for such transmitters.

  2. Cross-reactive microbial peptides can modulate HIV-specific CD8+ T cell responses.

    Directory of Open Access Journals (Sweden)

    Christopher W Pohlmeyer

    Full Text Available Heterologous immunity is an important aspect of the adaptive immune response. We hypothesized that this process could modulate the HIV-1-specific CD8+ T cell response, which has been shown to play an important role in HIV-1 immunity and control. We found that stimulation of peripheral blood mononuclear cells (PBMCs from HIV-1-positive subjects with microbial peptides that were cross-reactive with immunodominant HIV-1 epitopes resulted in dramatic expansion of HIV-1-specific CD8+ T cells. Interestingly, the TCR repertoire of HIV-1-specific CD8+ T cells generated by ex vivo stimulation of PBMCs using HIV-1 peptide was different from that of cells stimulated with cross-reactive microbial peptides in some HIV-1-positive subjects. Despite these differences, CD8+ T cells stimulated with either HIV-1 or cross-reactive peptides effectively suppressed HIV-1 replication in autologous CD4+ T cells. These data suggest that exposure to cross-reactive microbial antigens can modulate HIV-1-specific immunity.

  3. Theory of coherent quantum phase slips in Josephson junction chains with periodic spatial modulations

    Science.gov (United States)

    Svetogorov, Aleksandr E.; Taguchi, Masahiko; Tokura, Yasuhiro; Basko, Denis M.; Hekking, Frank W. J.

    2018-03-01

    We study coherent quantum phase slips which lift the ground state degeneracy in a Josephson junction ring, pierced by a magnetic flux of the magnitude equal to half of a flux quantum. The quantum phase-slip amplitude is sensitive to the normal mode structure of superconducting phase oscillations in the ring (Mooij-Schön modes). These, in turn, are affected by spatial inhomogeneities in the ring. We analyze the case of weak periodic modulations of the system parameters and calculate the corresponding modification of the quantum phase-slip amplitude.

  4. Three-Phase Modulated Pole Machine Topologies Utilizing Mutual Flux Paths

    DEFF Research Database (Denmark)

    Washington, Jamie G.; Atkinson, Glynn J.; Baker, Nick J.

    2012-01-01

    This paper discusses three-phase topologies for modulated pole machines (MPMs). The authors introduce a new threephase topology, which takes advantage of mutual flux paths; this is analyzed using 3-D finite-element methods and compared to a three-phase topology using three single-phase units...... stacked axially. The results show that the new “combined-phase MPM” exhibits a greater torque density, while offering a reduction in the number of components. The results obtained from two prototypes are also presented to verify the concept; the results show that the “combined-phase” machine could provide...

  5. Characterization of ultrashort laser pulses employing self-phase modulation dispersion-scan technique

    Science.gov (United States)

    Sharba, A. B.; Chekhlov, O.; Wyatt, A. S.; Pattathil, R.; Borghesi, M.; Sarri, G.

    2018-03-01

    We present a new phase characterization technique for ultrashort laser pulses that employs self-phase modulation (SPM) in the dispersion scan approach. The method can be implemented by recording a set of nonlinearly modulated spectra generated with a set of known chirp values. The unknown phase of the pulse is retrieved by linking the recorded spectra to the initial spectrum of the pulse via a phase function guessed by a function minimization iterative algorithm. This technique has many advantages over the dispersion scan techniques that use frequency conversion processes. Mainly, the use of SPM cancels out the phase and group velocity mismatch errors and dramatically widens the spectral acceptance of the nonlinear medium and the range of working wavelength. The robustness of the technique is demonstrated with smooth and complex phase retrievals using numerical examples. The method is shown to be not affected by the spatial distribution of the beam or the presence of nonlinear absorption process. In addition, we present an efficient method for phase representation based on a summation of a set of Gaussian functions. The independence of the functions from each other prevents phase coupling of any kind and facilitates a flexible phase representation.

  6. Commensurate and incommensurate '5M' modulated crystal structures in Ni-Mn-Ga martensitic phases

    International Nuclear Information System (INIS)

    Righi, L.; Albertini, F.; Pareti, L.; Paoluzi, A.; Calestani, G.

    2007-01-01

    It is well known that the composition of ferromagnetic shape memory Ni-Mn-Ga Heusler alloys determines both temperature of martensitic transformations and the structure type of the product phase. In the present work we focused our attention on the structural study of the so-called '5M' modulated structure. In particular, the structure of Ni 1.95 Mn 1.19 Ga 0.86 martensitic phase is analysed by powder X-ray diffraction (PXRD) and compared with that of the stoichiometric Ni 2 MnGa martensite. The study of the diffraction data reveals the occurrence of commensurate (C) structural modulation in Ni 1.95 Mn 1.19 Ga 0.86 ; this contrasts with Ni 2 MnGa, where an incommensurate (IC) structural modulation was evident. The two phases also differ in the symmetry of the fundamental martensitic lattice. In fact, the incommensurate modulation is related to an orthorhombic basic structure, while the commensurate variant presents a monoclinic symmetry. The commensurate modulated structure has been investigated by using the superspace approach already adopted to solve the structure of Ni 2 MnGa martensite. The structure has been determined by Rietveld refinement of PXRD data

  7. Multilevel Modulation formats for Optical Communication

    DEFF Research Database (Denmark)

    Jensen, Jesper Bevensee

    2008-01-01

    This thesis studies the use of multilevel modulation formats for optical communication systems. Multilevel modulation is an attractive method of increasing the spectral efficiency of optical communication systems. Various modulation formats employing phase modulation, amplitude modulation...... or a combination of the two have been studied. The use of polarization multiplexing (PolMux) to double the bit rate has also been investigated. The impact of transmission impairments such as chromatic dispersion, self phase modulation and cross phase modulation has been investigated. The feasibility of multilevel...... modulation for network oriented scenarios has been demonstrated....

  8. Intrinsically stable phase-modulated polarization encoding system for quantum key distribution

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xiaobao [Laboratory of Photonic Information Technology, School for Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou 510006 (China); Liao Changjun [Laboratory of Photonic Information Technology, School for Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou 510006 (China)], E-mail: chliao@scnu.edu.cn; Mi Jinglong; Wang Jindong; Liu Songhao [Laboratory of Photonic Information Technology, School for Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou 510006 (China)

    2008-12-22

    We demonstrate experimentally an intrinsically stable polarization coding and decoding system composed of optical-fiber Sagnac interferometers with integrated phase modulators for quantum key distribution. An interference visibility of 98.35% can be kept longtime during the experiment without any efforts of active compensation for coding all four desired polarization states.

  9. Performance Evaluation of Digital Coherent Receivers for Phase-Modulated Radio-Over-Fiber Links

    DEFF Research Database (Denmark)

    Caballero Jambrina, Antonio; Zibar, Darko; Tafur Monroy, Idelfonso

    2011-01-01

    The performance of optical phase-modulated (PM) radio-over-fiber (RoF) links assisted with coherent detection and digital signal processing (PM-Coh) is analyzed and experimentally demonstrated for next-generation wireless-over-fiber systems. PM-Coh offers high linearity for transparent transport ...

  10. Multiband carrierless amplitude/phase modulation for ultra-wideband high data rate wireless communications

    DEFF Research Database (Denmark)

    Puerta Ramírez, Rafael; Rommel, Simon; Altabas, Jose A.

    2016-01-01

    We report on the first experimental demonstration of carrierless amplitude/phase modulation in a flexible multiband approach for ultrawideband high-data-rate wireless communications. An effective bitrate of 2 GB/s is achieved while complying with the restrictions on the effective radiated power...

  11. Double-Carrier Phase-Disposition Pulse Width Modulation Method for Modular Multilevel Converters

    DEFF Research Database (Denmark)

    Zhou, Fayun; Luo, An; Li, Yan

    2017-01-01

    Modular multilevel converters (MMCs) have become one of the most attractive topologies for high-voltage and high-power applications. A double-carrier phase disposition pulse width modulation (DCPDPWM) method for MMCs is proposed in this paper. Only double triangular carriers with displacement ang......, the proposed method and theoretical analysis are verified by simulation and experimental results. View Full-Text...

  12. Coherent Control of Photofragment Distributions Using Laser Phase Modulation in the Weak-Field Limit

    DEFF Research Database (Denmark)

    Garcia-Vela, Alberto; Henriksen, Niels Engholm

    2015-01-01

    The possibility of quantum interference control of the final state distributions of photodissociation fragments by means of pure phase modulation of the pump laser pulse in the weak-field regime is demonstrated theoretically for the first time. The specific application involves realistic wave pac...

  13. Microstrip linear phase low pass filter based on defected ground structures for partial response modulation

    DEFF Research Database (Denmark)

    Cimoli, Bruno; Johansen, Tom Keinicke; Olmos, Juan Jose Vegas

    2018-01-01

    We report a high performance linear phase low pass filter (LPF) designed for partial response (PR) modulations. For the implementation, we adopted microstrip technology and a variant of the standard stepped‐impedance technique. Defected ground structures (DGS) are used for increasing the characte......We report a high performance linear phase low pass filter (LPF) designed for partial response (PR) modulations. For the implementation, we adopted microstrip technology and a variant of the standard stepped‐impedance technique. Defected ground structures (DGS) are used for increasing...... the characteristic impedance of transmission lines. Experimental results prove that the proposed filter can successfully modulate a non‐return‐to‐zero (NRZ) signal into a five levels PR one....

  14. The optimal input optical pulse shape for the self-phase modulation based chirp generator

    Science.gov (United States)

    Zachinyaev, Yuriy; Rumyantsev, Konstantin

    2018-04-01

    The work is aimed to obtain the optimal shape of the input optical pulse for the proper functioning of the self-phase modulation based chirp generator allowing to achieve high values of chirp frequency deviation. During the research, the structure of the device based on self-phase modulation effect using has been analyzed. The influence of the input optical pulse shape of the transmitting optical module on the chirp frequency deviation has been studied. The relationship between the frequency deviation of the generated chirp and frequency linearity for the three options for implementation of the pulse shape has been also estimated. The results of research are related to the development of the theory of radio processors based on fiber-optic structures and can be used in radars, secure communications, geolocation and tomography.

  15. The ferroelectric phase transition and modulated valence electrons in the incommensurate phase of ammonium tetrafluoroberyllate

    Czech Academy of Sciences Publication Activity Database

    Palatinus, Lukáš; van Smaalen, S.

    2004-01-01

    Roč. 305, - (2004), s. 49-52 ISSN 0015-0193 Grant - others:DFG and FCI(DE) XX Institutional research plan: CEZ:AV0Z1010914 Keywords : Maximum Entropy Method * modulated structures * charge density Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.517, year: 2004

  16. Generation of sinusoidal fringes with a holographic phase grating and a phase-only spatial light modulator

    International Nuclear Information System (INIS)

    Berberova, Natalia; Stoykova, Elena; Sainov, Ventseslav

    2012-01-01

    A variety of pattern projection methods for the three-dimensional capture of objects is based on the generation of purely sinusoidal fringes. This is not an easy task, especially when a portable non-interferometric system for outdoor usage is required. The use of phase gratings with coherent illumination as a possible solution has the advantage of providing good stability and a large measurement volume. In this work, we analyze the quality of fringes projected with two sinusoidal phase gratings. The first grating is recorded on a silver-halide holographic plate by means of a Michelson interferometer. The spatial resolution of the silver-halide material used is greater than 6000 lines per millimeter, and the recorded grating is practically analogous to a smooth variation of the phase profile. The second grating is formed as a sinusoidal phase variation on a liquid crystal-on-silicon phase-only reflective display with a resolution of 1920×1080 pixels, a pixel pitch of 8 μm and 256 phase levels. The frequency content of the fringes projected with both gratings is analyzed and compared on the basis of the calculated Fresnel diffraction pattern, taking into account that the sinusoidal phase distribution in the case of a spatial light modulator is both sampled and quantized. Experimental fringe patterns projected using both gratings are also provided.

  17. Synchrotron phase transition crossing using an rf harmonic

    International Nuclear Information System (INIS)

    Griffin, J.E.

    1991-03-01

    This paper describes a new method of transition crossing in strong focusing proton or heavy ion synchrotrons. Such accelerators have the property that at some energy, frequently within the operating range of the machine, the rotation period of particles within the momentum acceptance range of the machine becomes independent of momentum. 19 refs., 10 figs

  18. Phase shifts as functions of the cross section

    NARCIS (Netherlands)

    Atkinson, D.; Kaekebeke, M.; de Roo, M.

    1975-01-01

    We show that an elastic scattering amplitute may be defined as an implicit function of the differential cross section. A practical method is given for a numerical investigation of this dependence, both in the elastic and in the inelastic regions. In particular, we consider the case of a polynomial

  19. Temperature Regulation of Photovoltaic Module Using Phase Change Material: A Numerical Analysis and Experimental Investigation

    Directory of Open Access Journals (Sweden)

    Hasan Mahamudul

    2016-01-01

    Full Text Available This work represents an effective design of a temperature regulated PV module by integrating phase change materials for Malaysian weather condition. Through the numerical analysis and experimental investigation it has been shown that if a PCM layer of width 0.02 m of RT 35 is used as a cooling arrangement with a PV module, the surface temperature of the module is reduced by 10°C, which remains constant for a period of 4–6 hours. This reduction of temperature implies the increase in conversion efficiency of the module. Experiment as well as investigation has been carried out considering typical Malaysian weather. Obtained result has been validated by using experimental prototype and comparative analysis.

  20. Thick-to-Thin Filament Surface Distance Modulates Cross-Bridge Kinetics in Drosophila Flight Muscle

    Energy Technology Data Exchange (ETDEWEB)

    Tanner, Bertrand C.W.; Farman, Gerrie P.; Irving, Thomas C.; Maughan, David W.; Palmer, Bradley M.; Miller, Mark S. (IIT); (Vermont); (BU)

    2012-09-19

    The demembranated (skinned) muscle fiber preparation is widely used to investigate muscle contraction because the intracellular ionic conditions can be precisely controlled. However, plasma membrane removal results in a loss of osmotic regulation, causing abnormal hydration of the myofilament lattice and its proteins. We investigated the structural and functional consequences of varied myofilament lattice spacing and protein hydration on cross-bridge rates of force development and detachment in Drosophila melanogaster indirect flight muscle, using x-ray diffraction to compare the lattice spacing of dissected, osmotically compressed skinned fibers to native muscle fibers in living flies. Osmolytes of different sizes and exclusion properties (Dextran T-500 and T-10) were used to differentially alter lattice spacing and protein hydration. At in vivo lattice spacing, cross-bridge attachment time (t{sub on}) increased with higher osmotic pressures, consistent with a reduced cross-bridge detachment rate as myofilament protein hydration decreased. In contrast, in the swollen lattice, t{sub on} decreased with higher osmotic pressures. These divergent responses were reconciled using a structural model that predicts t{sub on} varies inversely with thick-to-thin filament surface distance, suggesting that cross-bridge rates of force development and detachment are modulated more by myofilament lattice geometry than protein hydration. Generalizing these findings, our results suggest that cross-bridge cycling rates slow as thick-to-thin filament surface distance decreases with sarcomere lengthening, and likewise, cross-bridge cycling rates increase during sarcomere shortening. Together, these structural changes may provide a mechanism for altering cross-bridge performance throughout a contraction-relaxation cycle.

  1. Modified Dual Three-Pulse Modulation technique for single-phase inverter topology

    Science.gov (United States)

    Sree Harsha, N. R.; Anitha, G. S.; Sreedevi, A.

    2016-01-01

    In a recent paper, a new modulation technique called Dual Three Pulse Modulation (DTPM) was proposed to improve the efficiency of the power converters of the Electric/Hybrid/Fuel-cell vehicles. It was simulated in PSIM 9.0.4 and uses analog multiplexers to generate the modulating signals for the DC/DC converter and inverter. The circuit used is complex and many other simulation softwares do not support the analog multiplexers as well. Also, the DTPM technique produces modulating signals for the converter, which are essentially needed to produce the modulating signals for the inverter. Hence, it cannot be used efficiently to switch the valves of a stand-alone inverter. We propose a new method to generate the modulating signals to switch MOSFETs of a single phase Dual-Three pulse Modulation based stand-alone inverter. The circuits proposed are simulated in Multisim 12.0. We also show an alternate way to switch a DC/DC converter in a way depicted by DTPM technique both in simulation (MATLAB/Simulink) and hardware. The circuitry is relatively simple and can be used for the further investigations of DTPM technique.

  2. Universal holonomic single quantum gates over a geometric spin with phase-modulated polarized light.

    Science.gov (United States)

    Ishida, Naoki; Nakamura, Takaaki; Tanaka, Touta; Mishima, Shota; Kano, Hiroki; Kuroiwa, Ryota; Sekiguchi, Yuhei; Kosaka, Hideo

    2018-05-15

    We demonstrate universal non-adiabatic non-abelian holonomic single quantum gates over a geometric electron spin with phase-modulated polarized light and 93% average fidelity. This allows purely geometric rotation around an arbitrary axis by any angle defined by light polarization and phase using a degenerate three-level Λ-type system in a negatively charged nitrogen-vacancy center in diamond. Since the control light is completely resonant to the ancillary excited state, the demonstrated holonomic gate not only is fast with low power, but also is precise without the dynamical phase being subject to control error and environmental noise. It thus allows pulse shaping for further fidelity.

  3. Measurement of the amplitude and phase transfer functions of an optical modulator using a heterodyne technique

    DEFF Research Database (Denmark)

    Romstad, Francis Pascal; Birkedal, Dan; Mørk, Jesper

    2001-01-01

    We present a new technique that measures the full amplitude and phase transfer curves of the modulator as a function of the applied bias, from which the small signal α-parameter can be calculated. The technique measures the amplitude and phase transfer functions simultaneously and directly......, compared to techniques where a time-consuming data analysis is necessary to calculate the a-parameter and an additional measurement is necessary to estimate the phase. Additionally, the chirp profile for all operation points can be calculated....

  4. Experimental investigation of the cascadability of a cross-gain modulation wavelength converter

    DEFF Research Database (Denmark)

    Zheng, Xueyan; Liu, Fenghai; Kloch, Allan

    2000-01-01

    by adding a fiber grating-based optical add-drop multiplexer after the semiconductor optical amplifier (SOA) to enhance the high-frequency response of the wavelength converter. However, the low-frequency degradation of the signal together with amplified spontaneous emission (ASE) noise and jitter......The cascading characteristics of a wavelength converter based on cross-gain modulation (XGM) are studied experimentally using a recirculating loop at 10 Gb/s. The maximum cascaded number of the wavelength converter converting the signal to the same wavelength is improved from five to eight...

  5. Enhanced wavefront reconstruction by random phase modulation with a phase diffuser

    DEFF Research Database (Denmark)

    Almoro, Percival F; Pedrini, Giancarlo; Gundu, Phanindra Narayan

    2011-01-01

    propagation in free space. The presentation of this technique is carried out using two setups. In the first setup, a diffuser plate is placed at the image plane of a metallic test object. The benefit of randomizing the phase of the object wave is the enhanced intensity recording due to high dynamic range...... of the diffusely scattered beam. The use of demagnification optics will also allow the investigations of relatively large objects. In the second setup, a transparent object is illuminated using a wavefront with random phase and constant amplitude by positioning the phase diffuser close to the object. The benefit...

  6. Shifts of Gamma Phase across Primary Visual Cortical Sites Reflect Dynamic Stimulus-Modulated Information Transfer.

    Science.gov (United States)

    Besserve, Michel; Lowe, Scott C; Logothetis, Nikos K; Schölkopf, Bernhard; Panzeri, Stefano

    2015-01-01

    Distributed neural processing likely entails the capability of networks to reconfigure dynamically the directionality and strength of their functional connections. Yet, the neural mechanisms that may allow such dynamic routing of the information flow are not yet fully understood. We investigated the role of gamma band (50-80 Hz) oscillations in transient modulations of communication among neural populations by using measures of direction-specific causal information transfer. We found that the local phase of gamma-band rhythmic activity exerted a stimulus-modulated and spatially-asymmetric directed effect on the firing rate of spatially separated populations within the primary visual cortex. The relationships between gamma phases at different sites (phase shifts) could be described as a stimulus-modulated gamma-band wave propagating along the spatial directions with the largest information transfer. We observed transient stimulus-related changes in the spatial configuration of phases (compatible with changes in direction of gamma wave propagation) accompanied by a relative increase of the amount of information flowing along the instantaneous direction of the gamma wave. These effects were specific to the gamma-band and suggest that the time-varying relationships between gamma phases at different locations mark, and possibly causally mediate, the dynamic reconfiguration of functional connections.

  7. Two-harmonic complex spectral-domain optical coherence tomography using achromatic sinusoidal phase modulation

    Science.gov (United States)

    Lu, Sheng-Hua; Huang, Siang-Ru; Chou, Che-Chung

    2018-03-01

    We resolve the complex conjugate ambiguity in spectral-domain optical coherence tomography (SD-OCT) by using achromatic two-harmonic method. Unlike previous researches, the optical phase of the fiber interferometer is modulated by an achromatic phase shifter based on an optical delay line. The achromatic phase modulation leads to a wavelength-independent scaling coefficient for the two harmonics. Dividing the mean absolute value of the first harmonic by that of the second harmonic in a B-scan interferogram directly gives the scaling coefficient. It greatly simplifies the determination of the magnitude ratio between the two harmonics without the need of third harmonic and cumbersome iterative calculations. The inverse fast Fourier transform of the complex-valued interferogram constructed with the scaling coefficient, first and second harmonics yields a full-range OCT image. Experimental results confirm the effectiveness of the proposed achromatic two-harmonic technique for suppressing the mirror artifacts in SD-OCT images.

  8. Influence of modulation method on using LC-traps with single-phase voltage source converters

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Min, Huang; Bai, Haofeng

    2015-01-01

    The switching-frequency LC-trap filter has recently been employed with high-order passive filters for Voltage Source Inverters (VSIs). This paper investigates the influence of modulation method on using the LC-traps with single-phase VSIs. Two-level (bipolar) and three-level (unipolar) modulations...... that include phase distortion and alternative phase opposition distortion methods are analyzed. Harmonic filtering performances of four LC-trap-based filters with different locations of LC-traps are compared. It is shown that the use of parallel-LC-traps in series with filter inductors, either grid...... or converter side, has a worse harmonic filtering performance than using series-LC-trap in the shunt branch. Simulations and experimental results are presented for verifications....

  9. Spectral Phase Modulation and chirped pulse amplification in High Gain Harmonic Generation

    CERN Document Server

    Wu, Zilu; Krinsky, Sam; Loos, Henrik; Murphy, James; Shaftan, Timur; Sheehy, Brian; Shen, Yuzhen; Wang, Xijie; Yu Li Hua

    2004-01-01

    High Gain Harmonic Generation (HGHG), because it produces longitudinally coherent pulses derived from a coherent seed, presents remarkable possibilities for manipulating FEL pulses. If spectral phase modulation imposed on the seed modulates the spectral phase of the HGHG in a deterministic fashion, then chirped pulse amplification, pulse shaping, and coherent control experiments at short wavelengths become possible. In addition, the details of the transfer function will likely depend on electron beam and radiator dynamics and so prove to be a useful tool for studying these. Using the DUVFEL at the National Synchrotron Light Source at Brookhaven National Laboratory, we present spectral phase analyses of both coherent HGHG and incoherent SASE ultraviolet FEL radiation, applying Spectral Interferometry for Direct Electric Field Reconstruction (SPIDER), and assess the potential for employing compression and shaping techniques.

  10. 77 FR 35425 - Crystalline Silicon Photovoltaic Cells and Modules From China; Scheduling of the Final Phase of...

    Science.gov (United States)

    2012-06-13

    ... Silicon Photovoltaic Cells and Modules From China; Scheduling of the Final Phase of Countervailing Duty... silicon photovoltaic cells and modules, provided for in subheadings 8501.31.80, 8501.61.00, 8507.20.80... photovoltaic cells, and modules, laminates, and panels, consisting of crystalline silicon photovoltaic cells...

  11. Phase Resolved Angular Velocity Control of Cross Flow Turbines

    Science.gov (United States)

    Strom, Benjamin; Brunton, Steven; Polagye, Brian

    2015-11-01

    Cross flow turbines have a number of operational advantages for the conversion of kinetic energy in marine or fluvial currents, but they are often less efficient than axial flow devices. Here a control scheme is presented in which the angular velocity of a cross flow turbine with two straight blades is prescribed as a function of azimuthal blade position, altering the time-varying effective angle of attack. Flume experiments conducted with a scale model turbine show approximately an 80% increase in turbine efficiency versus optimal constant angular velocity and constant resistive torque control schemes. Torque, drag, and lateral forces on one- and two-bladed turbines are analyzed and interpreted with bubble flow visualization to develop a simple model that describes the hydrodynamics responsible for the observed increase in mean efficiency. Challenges associated with implementing this control scheme on commercial-scale devices are discussed. If solutions are found, the performance increase presented here may impact the future development of cross flow turbines.

  12. Nature of low dimensional structural modulations and relative phase stability in RexMo(W)1-xS2 transition metal dichalcogenide alloys

    KAUST Repository

    Sahu, R.

    2017-03-08

    We report on the various types of Peierls like two dimensional structural modulations and relative phase stability of 2H and 1T poly-types in the RexMo1-xS2 and RexW1-xS2 alloy system. Theoretical calculation predicts a polytype phase transition cross over at ∼50 at. % of Mo and W in ReS2 in both monolayer and bulk form, respectively. Experimentally, two different types of structural modulations at 50% and a modulation corresponding to trimerization at 75% alloy composition are observed for RexMo1-xS2 and only one type of modulation is observed at the 50% RexW1-xS2 alloy system. The 50% alloy system is found to be a suitable monolithic candidate for metal semiconductor transition with minute external perturbation. ReS2 is known to be in the 2D Peierls distorted 1Td structure and forms a chain like superstructure. Incorporation of Mo and W atoms into the ReS2 lattice modifies the metal-metal hybridization between the cations and influences the structural modulation and electronic properties of the system. The results offer yet another effective way to tune the electronic structure and poly-type phases of this class of materials other than intercalation, strain, and vertical stacking arrangement.

  13. On calculating phase shifts and performing fits to scattering cross sections or transport properties

    International Nuclear Information System (INIS)

    Hepburn, J.W.; Roy, R.J. Le

    1978-01-01

    Improved methods of calculating quantum mechanical phase shifts and for performing least-squares fits to scattering cross sections or transport properties, are described. Their use in a five-parameter fit to experimental differential cross sections reduces the computer time by a factor of 4-7. (Auth.)

  14. Performance analysis of variable speed multiphase induction motor with pole phase modulation

    Directory of Open Access Journals (Sweden)

    Liu Huijuan

    2016-09-01

    Full Text Available The pole phase modulation (PPM technique is an effective method to extend speed range and torque capabilities for an integrated starter and hybrid electric vehicles applications. In this paper, the five pole-phase combination types of a multiphase induction motor (IM with 36 stator slots and 36 stator conductors are presented and compared quantitatively by using the time-stepping finite element method (TS-FEM. The 36 stator conductors of the proposed multiphase IM are fed by a 36 leg inverter and the current phase angle and amplitude of each stator conductor can be controlled independently. This paper focuses on the winding connection, the PPM technique and the performance comparative analysis of each pole-phase combination types of the proposed multiphase IM. The flux distribution, air-gap flux density, output torque, core losses and efficiency of five pole-phase combination types have been investigated.

  15. Optimized logarithmic phase masks used to generate defocus invariant modulation transfer function for wavefront coding system.

    Science.gov (United States)

    Zhao, Hui; Li, Yingcai

    2010-08-01

    In a previous Letter [Opt. Lett. 33, 1171 (2008)], we proposed an improved logarithmic phase mask by making modifications to the original one designed by Sherif. However, further studies in another paper [Appl. Opt. 49, 229 (2010)] show that even when the Sherif mask and the improved one are optimized, their corresponding defocused modulation transfer functions (MTFs) are still not stable with respect to focus errors. So, by further modifying their phase profiles, we design another two logarithmic phase masks that exhibit more stable defocused MTF. However, with the defocus-induced phase effect considered, we find that the performance of the two masks proposed in this Letter is better than the Sherif mask, but worse than our previously proposed phase mask, according to the Hilbert space angle.

  16. Operators Manual and Technical Reference for the Z-Beamlet Phase Modulation Failsafe System: Version 1.

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, Darrell J.

    2014-09-01

    The need for pulse energies exceeding 4 kJ and pulse lengths [?] 2 ns in Sandia's Z-Beamlet laser (ZBL) requires that the single-frequency spectrum of its fiber-laser master oscillator be converted to a phase modulated spectrum with a modulation in dex [?] 5. Because accidental injection of single-frequency light into ZBL could result i n damage to optical materials from transverse stimulated Brillouin scattering, the presence of phase modulated (PM) light must be monitored by a reliable failsafe system that can stop a las er shot within of a few 10's of ns following a failure of the PM system. This requirement is met by combining optical heterodyne detection with high-speed electronics to indicate the pres ence or absence of phase modulated light. The transition time for the failsafe signal resultin g from a sudden failure using this technique is approximately 35 ns. This is sufficiently short to safely stop a single-frequency laser pulse from leaving ZBL's regenerative amplifier with a n approximately 35 ns margin of safety. This manual and technical reference contains detai led instructions for daily use of the PM failsafe system and provides enough additional informat ion for its maintenance and repair.

  17. Radio over fiber transceiver employing phase modulation of an optical broadband source.

    Science.gov (United States)

    Grassi, Fulvio; Mora, José; Ortega, Beatriz; Capmany, José

    2010-10-11

    This paper proposes a low-cost RoF transceiver for multichannel SCM/WDM signal distribution suitable for future broadband access networks. The transceiver is based on the phase modulation of an optical broadband source centered at third transmission window. Prior to phase modulation the optical broadband source output signal is launched into a Mach-Zehnder interferometer structure, as key device enabling radio signals propagation over the optical link. Furthermore, an optical CWDM is employed to create a multichannel scenario by performing the spectral slicing of the modulated optical signal into a number of channels each one conveying the information from the central office to different base stations. The operation range is up to 20 GHz with a modulation bandwidth around of 500 MHz. Experimental results of the transmission of SCM QPSK and 64-QAM data through 20 Km of SMF exhibit good EVM results in the operative range determined by the phase-to-intensity conversion process. The proposed approach shows a great suitability for WDM networks based on RoF signal transport and also represents a cost-effective solution for passive optical networks.

  18. Selectivity enhancement in photoacoustic gas analysis via phase-sensitive detection at high modulation frequency

    Science.gov (United States)

    Kosterev, Anatoliy (Inventor)

    2010-01-01

    A method for detecting a target fluid in a fluid sample comprising a first fluid and the target fluid using photoacoustic spectroscopy (PAS), comprises a) providing a light source configured to introduce an optical signal having at least one wavelength into the fluid sample; b) modulating the optical signal at a desired modulation frequency such that the optical signal generates an acoustic signal in the fluid sample; c) measuring the acoustic signal in a resonant acoustic detector; and d) using the phase of the acoustic signal to detect the presence of the target fluid.

  19. Magnetic field modulated microwave spectroscopy across phase transitions and the search for new superconductors

    International Nuclear Information System (INIS)

    Ramírez, Juan Gabriel; Basaran, Ali C; De la Venta, J; Pereiro, Juan; Schuller, Ivan K

    2014-01-01

    This article introduces magnetic field modulated microwave spectroscopy (MFMMS) as a unique and high-sensitivity technique for use in the search for new superconductors. MFMMS measures reflected microwave power as a function of temperature. The modulation induced by the external ac magnetic field enables the use of phase locked detection with the consequent sensitivity enhancement. The MFMMS signal across several prototypical structural, magnetic, and electronic transitions is investigated. A literature review on microwave absorption across superconducting transitions is included. We show that MFMMS can be used to detect superconducting transitions selectively with very high sensitivity. (report on progress)

  20. All-optical microwave signal processing based on optical phase modulation

    Science.gov (United States)

    Zeng, Fei

    This thesis presents a theoretical and experimental study of optical phase modulation and its applications in all-optical microwave signal processing, which include all-optical microwave filtering, all-optical microwave mixing, optical code-division multiple-access (CDMA) coding, and ultrawideband (UWB) signal generation. All-optical microwave signal processing can be considered as the use of opto-electronic devices and systems to process microwave signals in the optical domain, which provides several significant advantages such as low loss, low dispersion, light weight, high time bandwidth products, and immunity to electromagnetic interference. In conventional approaches, the intensity of an optical carrier is modulated by a microwave signal based on direct modulation or external modulation. The intensity-modulated optical signal is then fed to a photonic circuit or system to achieve specific signal processing functionalities. The microwave signal being processed is usually obtained based on direct detection, i.e., an opto-electronic conversion by use of a photodiode. In this thesis, the research efforts are focused on the optical phase modulation and its applications in all-optical microwave signal processing. To avoid using coherent detection which is complicated and costly, simple and effective phase modulation to intensity modulation (PM-IM) conversion schemes are pursued. Based on a theoretical study of optical phase modulation, two approaches to achieving PM-IM conversions are proposed. In the first approach, the use of chromatic dispersion induced by a dispersive device to alter the phase relationships among the sidebands and the optical carrier of a phase-modulated optical signal to realize PM-IM conversion is investigated. In the second approach, instead of using a dispersive device, the PM-IM conversion is realized based on optical frequency discrimination implemented using an optical filter. We show that the proposed PM-IM conversion schemes can be

  1. Refractive index modulation of Sb70Te30 phase-change thin films by multiple femtosecond laser pulses

    International Nuclear Information System (INIS)

    Lei, Kai; Wang, Yang; Jiang, Minghui; Wu, Yiqun

    2016-01-01

    In this study, the controllable effective refractive index modulation of Sb 70 Te 30 phase-change thin films between amorphous and crystalline states was achieved experimentally by multiple femtosecond laser pulses. The modulation mechanism was analyzed comprehensively by a spectral ellipsometer measurement, surface morphology observation, and two-temperature model calculations. We numerically demonstrate the application of the optically modulated refractive index of the phase-change thin films in a precisely adjustable color display. These results may provide further insights into ultrafast phase-transition mechanics and are useful in the design of programmable photonic and opto-electrical devices based on phase-change memory materials.

  2. Experimental investigation of turbulence modulation in particle-laden coaxial jets by Phase Doppler Anemometry

    Energy Technology Data Exchange (ETDEWEB)

    Mergheni, M.A. [CORIA UMR 6614 CNRS, Universite et INSA de ROUEN, Avenue de l' Universite, BP 12, 76801 Saint Etienne du Rouvray, Cedex (France)]|[LESTE Ecole Nationale d' Ingenieurs de Monastir, 5019 Monastir (Tunisia); Sautet, J.C.; Godard, G. [CORIA UMR 6614 CNRS, Universite et INSA de ROUEN, Avenue de l' Universite, BP 12, 76801 Saint Etienne du Rouvray, Cedex (France); Ben Ticha, H.; Ben Nasrallah, S. [LESTE Ecole Nationale d' Ingenieurs de Monastir, 5019 Monastir (Tunisia)

    2009-03-15

    The effect of solid particles on the flow characteristics of axisymmetric turbulent coaxial jets for two flow conditions was studied. Simultaneous measurements of size and velocity distributions of continuous and dispersed phases in a two-phase flow are presented using a Phase Doppler Anemometry (PDA) technique. Spherical glass particles with a particle diameter range from 102 to 212 {mu}m were used in this two-phase flow, the experimental results indicate a significant influence of the solid particles and the Re on the flow characteristics. The data show that the gas phase has lower mean velocity in the near-injector region and a higher mean velocity at the developed region. Near the injector at low Reynolds number (Re = 2839) the presence of the particles dampens the gas-phase turbulence, while at higher Reynolds number (Re = 11 893) the gas-phase turbulence and the velocity fluctuation of particle-laden jets are increased. The particle velocity at higher Reynolds number (Re = 11 893) and is lower at lower Reynolds number (Re = 2839). The slip velocity between particles and gas phase existed over the flow domain was examined. More importantly, the present experiment results suggest that, consideration of the gas characteristic length scales is insufficient to predict gas-phase turbulence modulation in gas-particle flows. (author)

  3. Design and assembly of the optical modules for phase-2 of the NEMO project

    Energy Technology Data Exchange (ETDEWEB)

    Leonora, E., E-mail: emanuele.leonora@ct.infn.it; Aiello, S.

    2013-10-11

    The NEMO collaboration team has undertaken a Phase-2 project, which aims at the realization and installation of a new infrastructure at the Capo Passero (Italy) deep-sea site at a depth of 3500 m. With this objective in mind, a fully equipped tower with 8-storey hosting two optical modules at each end is under construction. Following a well established procedure, 32 optical modules have been assembled. The optical module consists of a large area photomultiplier tube enclosed in a pressure resistant glass sphere with a diameter of 13 in. The photomultiplier is a R7081 type, produced by Hamamatsu, with a photocathode area with a diameter of 10 in. and 10 dynodes. Mechanical and optical contacts between the front of the photomultiplier tube and the glass surface are ensured by an optical bi-component silicone gel. A mu-metal cage is used to shield the photomultiplier against the influence of the Earth's magnetic field.

  4. Optical signal processing techniques and applications of optical phase modulation in high-speed communication systems

    Science.gov (United States)

    Deng, Ning

    In recent years, optical phase modulation has attracted much research attention in the field of fiber optic communications. Compared with the traditional optical intensity-modulated signal, one of the main merits of the optical phase-modulated signal is the better transmission performance. For optical phase modulation, in spite of the comprehensive study of its transmission performance, only a little research has been carried out in terms of its functions, applications and signal processing for future optical networks. These issues are systematically investigated in this thesis. The research findings suggest that optical phase modulation and its signal processing can greatly facilitate flexible network functions and high bandwidth which can be enjoyed by end users. In the thesis, the most important physical-layer technology, signal processing and multiplexing, are investigated with optical phase-modulated signals. Novel and advantageous signal processing and multiplexing approaches are proposed and studied. Experimental investigations are also reported and discussed in the thesis. Optical time-division multiplexing and demultiplexing. With the ever-increasing demand on communication bandwidth, optical time division multiplexing (OTDM) is an effective approach to upgrade the capacity of each wavelength channel in current optical systems. OTDM multiplexing can be simply realized, however, the demultiplexing requires relatively complicated signal processing and stringent timing control, and thus hinders its practicability. To tackle this problem, in this thesis a new OTDM scheme with hybrid DPSK and OOK signals is proposed. Experimental investigation shows this scheme can greatly enhance the demultiplexing timing misalignment and improve the demultiplexing performance, and thus make OTDM more practical and cost effective. All-optical signal processing. In current and future optical communication systems and networks, the data rate per wavelength has been approaching

  5. Phase structure of generalized Cross-Neveu models

    International Nuclear Information System (INIS)

    Klimenko, K.G.

    1987-01-01

    A phase structure of models with n spinor multiplets has been considered in the space-time of dimension D=2,3. In the case when n=2 and D=3 there may occur vaccums | +> violating chiral invariance, as well as |-> violating P,T symmetry of the model. At D,n=2 depending on the sign of the constant g 12 there also exist two different vacua. It is shown here, that at sufficiently small g 12 the description of the model with the help of the leading order of 1/N expansion is incorrect (there appear tachyons). The properties of Gross-Neveu model have been dealt with at D=3, n=1 and the temperature and chemical potential not equal to zero

  6. Coherent x-ray diffraction imaging of paint pigment particles by scanning a phase plate modulator

    International Nuclear Information System (INIS)

    Chu, Y.S.; Chen, B.; Zhang, F.; Berenguer, F.; Bean, R.; Kewish, C.; Vila-Comamala, J.; Rodenburg, J.; Robinson, I.

    2011-01-01

    We have implemented a coherent x-ray diffraction imaging technique that scans a phase plate to modulate wave-fronts of the x-ray beam transmitted by samples. The method was applied to measure a decorative alkyd paint containing iron oxide red pigment particles. By employing an iterative algorithm for wave-front modulation phase retrieval, we obtained an image of the paint sample that shows the distribution of the pigment particles and is consistent with the result obtained from a transmission x-ray microscope. The technique has been experimentally proven to be a feasible coherent x-ray imaging method with about 120 nm spatial resolution and was shown to work well with industrially relevant specimens.

  7. On The Use of A Phase Modulation Method for Decorrelation in Acoustic Feedback Cancellation

    DEFF Research Database (Denmark)

    Guo, Meng; Jensen, Søren Holdt; Jensen, Jesper

    2012-01-01

    A major problem in using an adaptive filter in acoustic feedback cancellation systems is that the loudspeaker signal is correlated with the signals entering the microphones of the audio system, leading to biased filter estimates. One possible solution for reducing this problem is by means...... of decorrelation. In this work, we study a subband phase modulation method, which was originally proposed for decorrelation in multichannel acoustic echo cancellation systems. We determine if this method is effective for decorrelation in acoustic feedback cancellation systems by comparing it to a structurally...... similar frequency shifting decorrelation method. We show that the phase modulation method is suitable for decorrelation in a hearing aid acoustic feedback cancellation system, although the frequency shifting method is in general slightly more effective....

  8. Modulation of task-related cortical connectivity in the acute and subacute phase after stroke

    DEFF Research Database (Denmark)

    Larsen, Lisbeth H.; Zibrandtsen, Ivan C.; Wienecke, Troels

    2018-01-01

    The functional relevance of cortical reorganization post-stroke is still not well understood. In this study, we investigated task-specific modulation of cortical connectivity between neural oscillations in key motor regions during the early phase after stroke. EEG and EMG recordings were examined...... from 15 patients and 18 controls during a precision grip task using the affected hand. Each patient attended two sessions in the acute and subacute phase (median of 3 and 34 days) post-stroke. Dynamic causal modelling (DCM) for induced responses was used to investigate task-specific modulations...... of oscillatory couplings in a bilateral network comprising supplementary motor area (SMA), dorsal premotor cortex (PMd) and primary motor cortex (M1). Fourteen models were constructed for each subject, and the input induced by the experimental manipulation (task) was set to inferior parietal lobule (IPL...

  9. Single phase-change analysis of two different PCMs filled in a heat transfer module

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong Gyu; Kang, Chae Dong [Chonbuk National University, Jeonju (Korea, Republic of); Kim, Hyung Kuk [Hyundai Heavy Industries Co., Ulsan (Korea, Republic of)

    2014-07-15

    Phase change material(PCM) is tried to secondary heat source in solar heat pump system. A numerical study of the phase change dominant heat transfer is done with a heat transfer module, which consists of a water path(BRINE), heat transfer plates(HTP), and PCM layers of high-temperature one(HPCM, 78-79 .deg. C) and low-temperature one(LPCM, 28-29 .deg. C). There are five arrangements consisting of BRINE, HTP, HPCM, and LPCM layers in the heat transfer module. The time and heat transfer rate for PCM melting/solidification are compared between arrangements. And the numerical time without convection is compared to the experimental one for melting/solidification. From the numerical analysis, the time for melting/solidification is different to 10 hours, depending on the arrangement.

  10. Half-metal phases in a quantum wire with modulated spin-orbit interaction

    Science.gov (United States)

    Cabra, D. C.; Rossini, G. L.; Ferraz, A.; Japaridze, G. I.; Johannesson, H.

    2017-11-01

    We propose a spin filter device based on the interplay of a modulated spin-orbit interaction and a uniform external magnetic field acting on a quantum wire. Half-metal phases, where electrons with only a selected spin polarization exhibit ballistic conductance, can be tuned by varying the magnetic field. These half-metal phases are proven to be robust against electron-electron repulsive interactions. Our results arise from a combination of explicit band diagonalization, bosonization techniques, and extensive density matrix renormalization group computations.

  11. Fabricating and Characterizing the Microfluidic Solid Phase Extraction Module Coupling with Integrated ESI Emitters

    Directory of Open Access Journals (Sweden)

    Hangbin Tang

    2018-05-01

    Full Text Available Microfluidic chips coupling with mass spectrometry (MS will be of great significance to the development of relevant instruments involving chemical and bio-chemical analysis, drug detection, food and environmental applications and so on. In our previous works, we proposed two types of microfluidic electrospray ionization (ESI chip coupling with MS: the two-phase flow focusing (FF ESI microfluidic chip and the corner-integrated ESI emitter, respectively. However the pretreatment module integrated with these ESI emitters is still a challenging problem. In this paper, we concentrated on integrating the solid phase micro-extraction (SPME module with our previous proposed on-chip ESI emitters; the fabrication processes of such SPME module are fully compatible with our previous proposed ESI emitters based on the multi-layer soft lithography. We optimized the structure of the integrated chip and characterized its performance using standard samples. Furthermore, we verified its abilities of salt removal, extraction of multiple analytes and separation through on-chip elution using mimic biological urine spiked with different drugs. The results indicated that our proposed integrated module with ESI emitters is practical and effective for real biological sample pretreatment and MS detection.

  12. A simple image-reject mixer based on two parallel phase modulators

    Science.gov (United States)

    Hu, Dapeng; Zhao, Shanghong; Zhu, Zihang; Li, Xuan; Qu, Kun; Lin, Tao; Zhang, Kun

    2018-02-01

    A simple photonic microwave image-reject mixer (IRM) using two parallel phase modulators is proposed. First, a photonic microwave mixer with phase shift ability is achieved using two parallel phase modulators (PMs), an optical bandpass filter, three polarization controllers, three polarization beam splitters and two balanced photodetectors. At the output of the mixer, two frequency downconverted signals with tunable frequency difference can be obtained. By adjusting the phase difference as 90° and utilizing an electrical 90° hybrid, the useless components can be eliminated, and the image reject operation is realized. The key advantage of the proposed scheme is the usage of PM, which avoid the DC bias shifting problem and make the system simple and stable. A simulation is performed to verify the proposed scheme, a relative - 90° or 90° phase shift can be obtained between the two output ports of the photonic microwave mixer, at the output of the IRM, 60 dB image-reject ratio is obtained.

  13. Wave packet interferometry and quantum state reconstruction by acousto-optic phase modulation

    International Nuclear Information System (INIS)

    Tekavec, Patrick F.; Dyke, Thomas R.; Marcus, Andrew H.

    2006-01-01

    Studies of wave packet dynamics often involve phase-selective measurements of coherent optical signals generated from sequences of ultrashort laser pulses. In wave packet interferometry (WPI), the separation between the temporal envelopes of the pulses must be precisely monitored or maintained. Here we introduce a new (and easy to implement) experimental scheme for phase-selective measurements that combines acousto-optic phase modulation with ultrashort laser excitation to produce an intensity-modulated fluorescence signal. Synchronous detection, with respect to an appropriately constructed reference, allows the signal to be simultaneously measured at two phases differing by 90 deg. Our method effectively decouples the relative temporal phase from the pulse envelopes of a collinear train of optical pulse pairs. We thus achieve a robust and high signal-to-noise scheme for WPI applications, such as quantum state reconstruction and electronic spectroscopy. The validity of the method is demonstrated, and state reconstruction is performed, on a model quantum system - atomic Rb vapor. Moreover, we show that our measurements recover the correct separation between the absorptive and dispersive contributions to the system susceptibility

  14. Injection of a Phase Modulated Source into the Z-Beamlet Laser for Increased Energy Extraction.

    Energy Technology Data Exchange (ETDEWEB)

    Rambo, Patrick K.; Armstrong, Darrell J.; Schwarz, Jens; Smith, Ian C; Shores, Jonathon; Speas, Christopher; Porter, John L.

    2014-11-01

    The Z-Beamlet laser has been operating at Sandia National Laboratories since 2001 to provide a source of laser-generated x-rays for radiography of events on the Z-Accelerator. Changes in desired operational scope have necessitated the increase in pulse duration and energy available from the laser system. This is enabled via the addition of a phase modulated seed laser as an alternative front-end. The practical aspects of deployment are discussed here.

  15. On the application of neural networks to the classification of phase modulated waveforms

    Science.gov (United States)

    Buchenroth, Anthony; Yim, Joong Gon; Nowak, Michael; Chakravarthy, Vasu

    2017-04-01

    Accurate classification of phase modulated radar waveforms is a well-known problem in spectrum sensing. Identification of such waveforms aids situational awareness enabling radar and communications spectrum sharing. While various feature extraction and engineering approaches have sought to address this problem, the use of a machine learning algorithm that best utilizes these features is becomes foremost. In this effort, a comparison of a standard shallow and a deep learning approach are explored. Experiments provide insights into classifier architecture, training procedure, and performance.

  16. Photon-counting 1.0 GHz-phase-modulation fluorometer

    Energy Technology Data Exchange (ETDEWEB)

    Mizuno, T.; Nakao, S.; Mizutani, Y.; Iwata, T., E-mail: iwata@tokushima-u.ac.jp [Division of Energy System, Institute of Technology and Science, Tokushima University, 2-1 Minami-Jyosanjima, Tokushima 770-8506 (Japan)

    2015-04-15

    We have constructed an improved version of a photon-counting phase-modulation fluorometer (PC-PMF) with a maximum modulation frequency of 1.0 GHz, where a phase domain measurement is conducted with a time-correlated single-photon-counting electronics. While the basic concept of the PC-PMF has been reported previously by one of the authors, little attention has been paid to its significance, other than its weak fluorescence measurement capability. Recently, we have recognized the importance of the PC-PMF and its potential for fluorescence lifetime measurements. One important aspect of the PC-PMF is that it enables us to perform high-speed measurements that exceed the frequency bandwidths of the photomultiplier tubes that are commonly used as fluorescence detectors. We describe the advantages of the PC-PMF and demonstrate its usefulness based on fundamental performance tests. In our new version of the PC-PMF, we have used a laser diode (LD) as an excitation light source rather than the light-emitting diode that was used in the primary version. We have also designed a simple and stable LD driver to modulate the device. Additionally, we have obtained a sinusoidal histogram waveform that has multiple cycles within a time span to be measured, which is indispensable for precise phase measurements. With focus on the fluorescence intensity and the resolution time, we have compared the performance of the PC-PMF with that of a conventional PMF using the analogue light detection method.

  17. Photon-counting 1.0 GHz-phase-modulation fluorometer

    International Nuclear Information System (INIS)

    Mizuno, T.; Nakao, S.; Mizutani, Y.; Iwata, T.

    2015-01-01

    We have constructed an improved version of a photon-counting phase-modulation fluorometer (PC-PMF) with a maximum modulation frequency of 1.0 GHz, where a phase domain measurement is conducted with a time-correlated single-photon-counting electronics. While the basic concept of the PC-PMF has been reported previously by one of the authors, little attention has been paid to its significance, other than its weak fluorescence measurement capability. Recently, we have recognized the importance of the PC-PMF and its potential for fluorescence lifetime measurements. One important aspect of the PC-PMF is that it enables us to perform high-speed measurements that exceed the frequency bandwidths of the photomultiplier tubes that are commonly used as fluorescence detectors. We describe the advantages of the PC-PMF and demonstrate its usefulness based on fundamental performance tests. In our new version of the PC-PMF, we have used a laser diode (LD) as an excitation light source rather than the light-emitting diode that was used in the primary version. We have also designed a simple and stable LD driver to modulate the device. Additionally, we have obtained a sinusoidal histogram waveform that has multiple cycles within a time span to be measured, which is indispensable for precise phase measurements. With focus on the fluorescence intensity and the resolution time, we have compared the performance of the PC-PMF with that of a conventional PMF using the analogue light detection method

  18. Audiovisual Modulation in Mouse Primary Visual Cortex Depends on Cross-Modal Stimulus Configuration and Congruency.

    Science.gov (United States)

    Meijer, Guido T; Montijn, Jorrit S; Pennartz, Cyriel M A; Lansink, Carien S

    2017-09-06

    The sensory neocortex is a highly connected associative network that integrates information from multiple senses, even at the level of the primary sensory areas. Although a growing body of empirical evidence supports this view, the neural mechanisms of cross-modal integration in primary sensory areas, such as the primary visual cortex (V1), are still largely unknown. Using two-photon calcium imaging in awake mice, we show that the encoding of audiovisual stimuli in V1 neuronal populations is highly dependent on the features of the stimulus constituents. When the visual and auditory stimulus features were modulated at the same rate (i.e., temporally congruent), neurons responded with either an enhancement or suppression compared with unisensory visual stimuli, and their prevalence was balanced. Temporally incongruent tones or white-noise bursts included in audiovisual stimulus pairs resulted in predominant response suppression across the neuronal population. Visual contrast did not influence multisensory processing when the audiovisual stimulus pairs were congruent; however, when white-noise bursts were used, neurons generally showed response suppression when the visual stimulus contrast was high whereas this effect was absent when the visual contrast was low. Furthermore, a small fraction of V1 neurons, predominantly those located near the lateral border of V1, responded to sound alone. These results show that V1 is involved in the encoding of cross-modal interactions in a more versatile way than previously thought. SIGNIFICANCE STATEMENT The neural substrate of cross-modal integration is not limited to specialized cortical association areas but extends to primary sensory areas. Using two-photon imaging of large groups of neurons, we show that multisensory modulation of V1 populations is strongly determined by the individual and shared features of cross-modal stimulus constituents, such as contrast, frequency, congruency, and temporal structure. Congruent

  19. EDITAR: a module for reaction rate editing and cross-section averaging within the AUS neutronics code system

    International Nuclear Information System (INIS)

    Robinson, G.S.

    1986-03-01

    The EDITAR module of the AUS neutronics code system edits one and two-dimensional flux data pools produced by other AUS modules to form reaction rates for materials and their constituent nuclides, and to average cross sections over space and energy. The module includes a Bsub(L) flux calculation for application to cell leakage. The STATUS data pool of the AUS system is used to enable the 'unsmearing' of fluxes and nuclide editing with minimal user input. The module distinguishes between neutron and photon groups, and printed reaction rates are formed accordingly. Bilinear weighting may be used to obtain material reactivity worths and to average cross sections. Bilinear weighting is at present restricted to diffusion theory leakage estimates made using mesh-average fluxes

  20. Verification of KARMA GEOM/TRPT Module with Given Multi-group Cross Sections

    International Nuclear Information System (INIS)

    Koo, Bon Seung; Hong, Ser Gi; Song, Jae Seung

    2009-01-01

    KAERI has developed a two-dimensional multigroup transport theory code KARMA (Kernel Analyzer by Ray-tracing Method for Fuel Assembly). KARMA uses CMFD (Coarse Mesh Finite Difference) accelerated MOC (Method of Characteristics) method for burnup calculation on a single fuel pin, a fuel assembly and a core consisting of rectangular array of fuel pins. KARMA code intends to be employed as a nuclear design tool for the Korean commercial pressurizer water reactor. Prior to the application to actual assembly designs, the code has to be approved by regularity agency. Therefore, it is essential that the reliability of KARMA code should be sufficiently evaluated against well-defined benchmark problems. In this paper, verification of GEOM/TRPT modules of KARMA was performed to confirm a reliability of the KARMA transport solution via comparisons with Monte Carlo calculations by using a consistent set of multi-group macroscopic cross-sections

  1. Dependence of optical phase modulation on anchoring strength of dielectric shield wall surfaces in small liquid crystal pixels

    Science.gov (United States)

    Isomae, Yoshitomo; Shibata, Yosei; Ishinabe, Takahiro; Fujikake, Hideo

    2018-03-01

    We demonstrated that the uniform phase modulation in a pixel can be realized by optimizing the anchoring strength on the walls and the wall width in the dielectric shield wall structure, which is the needed pixel structure for realizing a 1-µm-pitch optical phase modulator. The anchoring force degrades the uniformity of the phase modulation in ON-state pixels, but it also keeps liquid crystals from rotating against the leakage of an electric field. We clarified that the optimal wall width and anchoring strength are 250 nm and less than 10-4 J/m2, respectively.

  2. Nanoscale phase engineering of thermal transport with a Josephson heat modulator

    Science.gov (United States)

    Fornieri, Antonio; Blanc, Christophe; Bosisio, Riccardo; D'Ambrosio, Sophie; Giazotto, Francesco

    2016-03-01

    Macroscopic quantum phase coherence has one of its pivotal expressions in the Josephson effect, which manifests itself both in charge and energy transport. The ability to master the amount of heat transferred through two tunnel-coupled superconductors by tuning their phase difference is the core of coherent caloritronics, and is expected to be a key tool in a number of nanoscience fields, including solid-state cooling, thermal isolation, radiation detection, quantum information and thermal logic. Here, we show the realization of the first balanced Josephson heat modulator designed to offer full control at the nanoscale over the phase-coherent component of thermal currents. Our device provides magnetic-flux-dependent temperature modulations up to 40 mK in amplitude with a maximum of the flux-to-temperature transfer coefficient reaching 200 mK per flux quantum at a bath temperature of 25 mK. Foremost, it demonstrates the exact correspondence in the phase engineering of charge and heat currents, breaking ground for advanced caloritronic nanodevices such as thermal splitters, heat pumps and time-dependent electronic engines.

  3. Single-Carrier Modulation for Neutral-Point-Clamped Inverters in Three-Phase Transformerless Photovoltaic Systems

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; Cavalcanti, Marcelo C.; Farias, Alexandre M.

    2013-01-01

    Modulation strategy is one of the most important issues for three-level neutral-point-clamped inverters in three-phase transformerless photovoltaic systems. A challenge for modulation is how to keep the common-mode voltages constant to reduce the leakage currents. A single-carrier modulation...... strategy is proposed. It has a very simple structure, and the common-mode voltages can be kept constant with no need of complex space-vector modulation or multicarrier pulsewidth modulation. Experimental results verify the theoretical analysis and the effectiveness of the presented method....

  4. Role of a Modulator in the Synthesis of Phase-Pure NU-1000.

    Science.gov (United States)

    Webber, Thomas E; Liu, Wei-Guang; Desai, Sai Puneet; Lu, Connie C; Truhlar, Donald G; Penn, R Lee

    2017-11-15

    NU-1000 is a robust, mesoporous metal-organic framework (MOF) with hexazirconium nodes ([Zr 6 O 16 H 16 ] 8+ , referred to as oxo-Zr 6 nodes) that can be synthesized by combining a solution of ZrOCl 2 ·8H 2 O and a benzoic acid modulator in N,N-dimethylformamide with a solution of linker (1,3,6,8-tetrakis(p-benzoic acid)pyrene, referred to as H 4 TBAPy) and by aging at an elevated temperature. Typically, the resulting crystals are primarily composed of NU-1000 domains that crystallize with a more dense phase that shares structural similarity with NU-901, which is an MOF composed of the same linker molecules and nodes. Density differences between the two polymorphs arise from the differences in the node orientation: in NU-1000, the oxo-Zr 6 nodes rotate 120° from node to node, whereas in NU-901, all nodes are aligned in parallel. Considering this structural difference leads to the hypothesis that changing the modulator from benzoic acid to a larger and more rigid biphenyl-4-carboxylic acid might lead to a stronger steric interaction between the modulator coordinating on the oxo-Zr 6 node and misaligned nodes or linkers in the large pore and inhibit the growth of the more dense NU-901-like material, resulting in phase-pure NU-1000. Side-by-side reactions comparing the products of synthesis using benzoic acid or biphenyl-4-carboxylic acid as a modulator produce structurally heterogeneous crystals and phase-pure NU-1000 crystals. It can be concluded that the larger and more rigid biphenyl-4-carboxylate inhibits the incorporation of nodes with an alignment parallel to the neighboring nodes already residing in the crystal.

  5. Thermal hydraulics-II. 2. Benchmarking of the TRIO Two-Phase-Flow Module

    International Nuclear Information System (INIS)

    Helton, Donald; Kumbaro, Anela; Hassan, Yassin

    2001-01-01

    The Commissariat a l'Energie Atomique (CEA) is currently developing a two-phase-flow module for the Trio-U CFD computer program. Work in the area of advanced numerical technique application to two-phase flow is being carried out by the SYSCO division at the CEA Saclay center. Recently, this division implemented several advanced numerical solvers, including approximate Riemann solvers and flux vector splitting schemes. As a test of these new advances, several benchmark tests were executed. This paper describes the pertinent results of this study. The first benchmark problem was the Ransom faucet problem. This problem consists of a vertical column of water acting under the gravity force. The appeal of this problem is that it tests the program's handling of the body force term and it has an analytical solution. The Trio results [based on a two-fluid, two-dimensional (2-D) simulation] for this problem were very encouraging. The two-phase-flow module was able to reproduce the analytical velocity and void fraction profiles. A reasonable amount of numerical diffusion was observed, and the numerical solution converged to the analytical solution as the grid size was refined, as shown in Fig. 1. A second series of benchmark problems is concerned with the employment of a drag force term. In a first approach, we test the capability of the code to take account of this source term, using a flux scheme solution technique. For this test, a rectangular duct was utilized. As shown in Fig. 2, mesh refinement results in an approach to the analytical solution. Next, a convergent/divergent nozzle problem is proposed. The nozzle is characterized by a brief contraction section and a long expansion section. A two-phase, 2-D, non-condensing model is used in conjunction with the Rieman solver. Figure 3 shows a comparison of the pressure profile for the experimental case and for the values calculated by the TRIO U two-phase-flow module. Trio was able to handle the drag force term and

  6. Damping coherent phase oscillations by means of path-length modulation

    International Nuclear Information System (INIS)

    Rees, J.R.

    1978-06-01

    Multi-bunch storage rings and synchrotrons are typically plagued by a tendency for the bunches to indulge in unstable coherent phase oscillations engendered by their electromagnetic interactions with the vacuum chamber. In many machines feedback systems have been used successfully to damp these oscillations using a signal proportional to the coherent phase motion or the concomitant energy motion to control an auxiliary longitudinal electric field. The purpose of this note is to describe an alternative feedback system which, using the same kind of a signal, modulates the path length of the orbit of the reference particle (the synchronous particle in the absence of coherent phase oscillations) in such a way as to damp coherent oscillations. 2 refs., 1 fig

  7. Optical techniques to feed and control GaAs MMIC modules for phased array antenna applications

    Science.gov (United States)

    Bhasin, K. B.; Anzic, G.; Kunath, R. R.; Connolly, D. J.

    1986-01-01

    A complex signal distribution system is required to feed and control GaAs monolithic microwave integrated circuits (MMICs) for phased array antenna applications above 20 GHz. Each MMIC module will require one or more RF lines, one or more bias voltage lines, and digital lines to provide a minimum of 10 bits of combined phase and gain control information. In a closely spaced array, the routing of these multiple lines presents difficult topology problems as well as a high probability of signal interference. To overcome GaAs MMIC phased array signal distribution problems optical fibers interconnected to monolithically integrated optical components with GaAs MMIC array elements are proposed as a solution. System architecture considerations using optical fibers are described. The analog and digital optical links to respectively feed and control MMIC elements are analyzed. It is concluded that a fiber optic network will reduce weight and complexity, and increase reliability and performance, but higher power will be required.

  8. Basis calculation of phase cross section library in a low power fast reactor neutronic simulation

    International Nuclear Information System (INIS)

    Jachic, J.

    1993-09-01

    In order to implement the utilization of the efficient multidimensional cubic SPLINE interpolation, we determine the phase library bases for net like relevant state components. A generic cubic surface and a weighted plane pertinent alternative interpolating methods used capable to generate cross sections values for fixed coordinates from cell code calculated data points is used. It is verified that the phase library bases increases or decrease smoothly and monotonically with the spectrum asymmetry and total flux buckling. This justifies its use in cross section updating avoiding cell calculations. (author)

  9. Cross-layer combining of adaptive modulation and truncated ARQ under cognitive radio resource requirements

    KAUST Repository

    Yang, Yuli; Ma, Hao; Aï ssa, Sonia

    2012-01-01

    In addressing the issue of taking full advantage of the shared spectrum under imposed limitations in a cognitive radio (CR) network, we exploit a cross-layer design for the communications of secondary users (SUs), which combines adaptive modulation and coding (AMC) at the physical layer with truncated automatic repeat request (ARQ) protocol at the data link layer. To achieve high spectral efficiency (SE) while maintaining a target packet loss probability (PLP), switching among different transmission modes is performed to match the time-varying propagation conditions pertaining to the secondary link. Herein, by minimizing the SU's packet error rate (PER) with each transmission mode subject to the spectrum-sharing constraints, we obtain the optimal power allocation at the secondary transmitter (ST) and then derive the probability density function (pdf) of the received SNR at the secondary receiver (SR). Based on these statistics, the SU's packet loss rate and average SE are obtained in closed form, considering transmissions over block-fading channels with different distributions. Our results quantify the relation between the performance of a secondary link exploiting the cross-layer-designed adaptive transmission and the interference inflicted on the primary user (PU) in CR networks. © 1967-2012 IEEE.

  10. Cross-layer combining of adaptive modulation and truncated ARQ under cognitive radio resource requirements

    KAUST Repository

    Yang, Yuli

    2012-11-01

    In addressing the issue of taking full advantage of the shared spectrum under imposed limitations in a cognitive radio (CR) network, we exploit a cross-layer design for the communications of secondary users (SUs), which combines adaptive modulation and coding (AMC) at the physical layer with truncated automatic repeat request (ARQ) protocol at the data link layer. To achieve high spectral efficiency (SE) while maintaining a target packet loss probability (PLP), switching among different transmission modes is performed to match the time-varying propagation conditions pertaining to the secondary link. Herein, by minimizing the SU\\'s packet error rate (PER) with each transmission mode subject to the spectrum-sharing constraints, we obtain the optimal power allocation at the secondary transmitter (ST) and then derive the probability density function (pdf) of the received SNR at the secondary receiver (SR). Based on these statistics, the SU\\'s packet loss rate and average SE are obtained in closed form, considering transmissions over block-fading channels with different distributions. Our results quantify the relation between the performance of a secondary link exploiting the cross-layer-designed adaptive transmission and the interference inflicted on the primary user (PU) in CR networks. © 1967-2012 IEEE.

  11. MIRANDA - a module based on multiregion resonance theory for generating cross sections within the AUS neutronics code system

    International Nuclear Information System (INIS)

    Robinson, G.S.

    1985-12-01

    MIRANDA is the cross-section generation module of the AUS neutronics code system used to prepare multigroup cross-section data which are pertinent to a particular study from a general purpose multigroup library of cross sections. Libraries have been prepared from ENDF/B which are suitable for thermal and fast fission reactors and for fusion blanket studies. The libraries include temperature dependent data, resonance cross sections represented by subgroup parameters and may contain photon as well as neutron data. The MIRANDA module includes a multiregion resonance calculation in slab, cylinder or cluster geometry, a homogeneous B L flux solution, and a group condensation facility. This report documents the modifications to an earlier version of MIRANDA and provides a complete user's manual

  12. Amplification of a bi-phase shift-key modulated signal by a mm-wave FEL

    International Nuclear Information System (INIS)

    Prosnitz, D.; Scharlemann, E.T.; Sheaffer, M.K.

    1991-10-01

    Bi-phase shift keying (BPSK) is a modulation scheme used in communications and radar in which the phase of a transmitted rf signal is switched in a coded pattern between discrete values differing by π radians. The transmitted information rate (in communications) or resolution (in imaging radar) depends on the rate at which the transmitted signal can be modulated. Modulation rates of greater than 1 GHz are generally desired. Although the instantaneous gain bandwidth of a mm-wave FEL amplifier can be much greater than 10 GHz, slippage may limit the BPSK modulation rate that can be amplified. Qualitative slippage arguments would limit the modulation rate to relatively low values; nevertheless, simulations with a time-dependent FEL code (GINGER) indicate that rates of 2 GHz or more are amplified without much loss in modulation integrity. In this paper we describe the effects of slippage in the simulations and discuss the limits of simple arguments

  13. Combined analysis of the radar cross-section modulation due to the long ocean waves around 14° and 34° incidence: Implication for the hydrodynamic modulation

    Science.gov (United States)

    Hauser, DanièLe; Caudal, GéRard

    1996-11-01

    The analysis of synthetic aperture radar observations over the ocean to derive the directional spectra of the waves is based upon a complex transfer function which is the sum of three terms: tilt modulation, hydrodynamic modulation, and velocity bunching effect. Both the hydrodynamic and the velocity bunching terms are still poorly known. Here we focus on the hydrodynamic part of the transfer function, from an experimental point of view. In this paper a new method is proposed to estimate the hydrodynamic modulation. The approach consists in analyzing observations obtained with an airborne real-aperture radar (called RESSAC). This radar (C band, HH polarized, broad beam of 14° × 3°) was used during the SEMAPHORE experiment, in two different modes. From the first mode (incidence angles from 7° to 21°) the directional spectra of the long waves are deduced under the assumption that the hydrodynamic modulation can be neglected (small incidence angles) and validated against in situ measurements. From the second mode (incidence angle from 27° to 41°) the amplitude and phase of the hydrodynamic modulation are deduced by combining the measured signal modulation spectrum at a mean incidence angle of 34° and the directional wave spectrum obtained from the first mode. The results, obtained in four different wind-wave cases of the SEMAPHORE experiment, show that the modulus of the hydrodynamic modulation is larger than that of the tilt modulation. Furthermore, we find that the modulus of the hydrodynamic transfer function is several times larger (by a factor 2-12) than the theoretical value proposed in previous works and 1.5-2.5 larger than experimental values reported in recent papers. The phase of the hydrodynamic modulation is found to be close to zero for waves propagating at an angle from the wind direction and between -20° and -40° for waves propagating along the wind direction. This indicates a significant influence of the wind-wave angle on the phase of the

  14. A Comparison of Phase-Shift Self- Oscillating and Carrier-based PWM Modulation for Embedded Audio Amplifiers

    OpenAIRE

    Huffenus , Alexandre; Pillonnet , Gaël; Abouchi , Nacer; Goutti , Frédéric

    2010-01-01

    International audience; This paper compares two modulation schemes for Class-D amplifiers: Phase-Shift Self-Oscillating (PSSO) and Carrier-Based Pulse Width Modulation (PWM). Theoretical analysis (modulation, frequency of oscillation, bandwidth…), design procedure, and IC silicon evaluation will be shown for mono and stereo operation (on the same silicon die) on both structures. The design of both architectures will use as many identical building blocks as possible, to provide a fair, "all el...

  15. On network coding and modulation mapping for three-phase bidirectional relaying

    KAUST Repository

    Chang, Ronald Y.; Lin, Sian Jheng; Chung, Wei-Ho

    2015-01-01

    © 2015 IEEE. In this paper, we consider the network coding (NC) enabled three-phase protocol for information exchange between two users in a wireless two-way (bidirectional) relay network. Modulo-based (nonbinary) and XOR-based (binary) NC schemes are considered as information mixture schemes at the relay while all transmissions adopt pulse amplitude modulation (PAM). We first obtain the optimal constellation mapping at the relay that maximizes the decoding performance at the users for each NC scheme. Then, we compare the two NC schemes, each in conjunction with the optimal constellation mapping at the relay, in different conditions. Our results demonstrate that, in the low SNR regime, binary NC outperforms nonbinary NC with 4-PAM, while they have mixed performance with 8-PAM. This observation applies to quadrature amplitude modulation (QAM) composed of two parallel PAMs.

  16. On network coding and modulation mapping for three-phase bidirectional relaying

    KAUST Repository

    Chang, Ronald Y.

    2015-12-03

    © 2015 IEEE. In this paper, we consider the network coding (NC) enabled three-phase protocol for information exchange between two users in a wireless two-way (bidirectional) relay network. Modulo-based (nonbinary) and XOR-based (binary) NC schemes are considered as information mixture schemes at the relay while all transmissions adopt pulse amplitude modulation (PAM). We first obtain the optimal constellation mapping at the relay that maximizes the decoding performance at the users for each NC scheme. Then, we compare the two NC schemes, each in conjunction with the optimal constellation mapping at the relay, in different conditions. Our results demonstrate that, in the low SNR regime, binary NC outperforms nonbinary NC with 4-PAM, while they have mixed performance with 8-PAM. This observation applies to quadrature amplitude modulation (QAM) composed of two parallel PAMs.

  17. From quantum physics to digital communication: Single sideband continuous phase modulation

    Science.gov (United States)

    Farès, Haïfa; Christian Glattli, D.; Louët, Yves; Palicot, Jacques; Moy, Christophe; Roulleau, Preden

    2018-01-01

    In the present paper, we propose a new frequency-shift keying continuous phase modulation (FSK-CPM) scheme having, by essence, the interesting feature of single-sideband (SSB) spectrum providing a very compact frequency occupation. First, the original principle, inspired from quantum physics (levitons), is presented. Besides, we address the problem of low-complexity coherent detection of this new waveform, based on orthonormal wave functions used to perform matched filtering for efficient demodulation. Consequently, this shows that the proposed modulation can operate using existing digital communication technology, since only well-known operations are performed (e.g., filtering, integration). This SSB property can be exploited to allow large bit rates transmissions at low carrier frequency without caring about image frequency degradation effects typical of ordinary double-sideband signals. xml:lang="fr"

  18. Ultrafast optical phase modulation with metallic nanoparticles in ion-implanted bilayer silica

    Energy Technology Data Exchange (ETDEWEB)

    Torres-Torres, C [Seccion de Estudios de Posgrado e Investigacion, ESIME-Z, Instituto Politecnico Nacional, Mexico, DF, 07738 (Mexico); Tamayo-Rivera, L; Silva-Pereyra, H G; Reyes-Esqueda, J A; Rodriguez-Fernandez, L; Crespo-Sosa, A; Cheang-Wong, J C; Oliver, A [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, 04510, Mexico, DF (Mexico); Rangel-Rojo, R [Departamento de Optica, Centro de Investigacion Cientifica y de Educacion Superior de Ensenada Apartado Postal 360, Ensenada, BC, 22860 (Mexico); Torres-Martinez, R, E-mail: crstorres@yahoo.com.mx [Centro de Investigacion en Ciencia Aplicada y TecnologIa Avanzada Unidad Queretaro, Instituto Politecnico Nacional, Santiago de Queretaro, Queretaro, 76090 (Mexico)

    2011-09-02

    The nonlinear optical response of metallic-nanoparticle-containing composites was studied with picosecond and femtosecond pulses. Two different types of nanocomposites were prepared by an ion-implantation process, one containing Au nanoparticles (NPs) and the other Ag NPs. In order to measure the optical nonlinearities, we used a picosecond self-diffraction experiment and the femtosecond time-resolved optical Kerr gate technique. In both cases, electronic polarization and saturated absorption were identified as the physical mechanisms responsible for the picosecond third-order nonlinear response for a near-resonant 532 nm excitation. In contrast, a purely electronic nonlinearity was detected at 830 nm with non-resonant 80 fs pulses. Regarding the nonlinear optical refractive behavior, the Au nanocomposite presented a self-defocusing effect, while the Ag one presented the opposite, that is, a self-focusing response. But, when evaluating the simultaneous contributions when the samples are tested as a multilayer sample (silica-Au NPs-silica-Ag NPs-silica), we were able to obtain optical phase modulation of ultra-short laser pulses, as a result of a significant optical Kerr effect present in these nanocomposites. This allowed us to implement an ultrafast all-optical phase modulator device by using a combination of two different metallic ion-implanted silica samples. This control of the optical phase is a consequence of the separate excitation of the nonlinear refracting phenomena exhibited by the separate Au and Ag nanocomposites.

  19. Threshold-voltage modulated phase change heterojunction for application of high density memory

    International Nuclear Information System (INIS)

    Yan, Baihan; Tong, Hao; Qian, Hang; Miao, Xiangshui

    2015-01-01

    Phase change random access memory is one of the most important candidates for the next generation non-volatile memory technology. However, the ability to reduce its memory size is compromised by the fundamental limitations inherent in the CMOS technology. While 0T1R configuration without any additional access transistor shows great advantages in improving the storage density, the leakage current and small operation window limit its application in large-scale arrays. In this work, phase change heterojunction based on GeTe and n-Si is fabricated to address those problems. The relationship between threshold voltage and doping concentration is investigated, and energy band diagrams and X-ray photoelectron spectroscopy measurements are provided to explain the results. The threshold voltage is modulated to provide a large operational window based on this relationship. The switching performance of the heterojunction is also tested, showing a good reverse characteristic, which could effectively decrease the leakage current. Furthermore, a reliable read-write-erase function is achieved during the tests. Phase change heterojunction is proposed for high-density memory, showing some notable advantages, such as modulated threshold voltage, large operational window, and low leakage current

  20. Threshold-voltage modulated phase change heterojunction for application of high density memory

    Science.gov (United States)

    Yan, Baihan; Tong, Hao; Qian, Hang; Miao, Xiangshui

    2015-09-01

    Phase change random access memory is one of the most important candidates for the next generation non-volatile memory technology. However, the ability to reduce its memory size is compromised by the fundamental limitations inherent in the CMOS technology. While 0T1R configuration without any additional access transistor shows great advantages in improving the storage density, the leakage current and small operation window limit its application in large-scale arrays. In this work, phase change heterojunction based on GeTe and n-Si is fabricated to address those problems. The relationship between threshold voltage and doping concentration is investigated, and energy band diagrams and X-ray photoelectron spectroscopy measurements are provided to explain the results. The threshold voltage is modulated to provide a large operational window based on this relationship. The switching performance of the heterojunction is also tested, showing a good reverse characteristic, which could effectively decrease the leakage current. Furthermore, a reliable read-write-erase function is achieved during the tests. Phase change heterojunction is proposed for high-density memory, showing some notable advantages, such as modulated threshold voltage, large operational window, and low leakage current.

  1. Quantum coherent optical phase modulation in an ultrafast transmission electron microscope.

    Science.gov (United States)

    Feist, Armin; Echternkamp, Katharina E; Schauss, Jakob; Yalunin, Sergey V; Schäfer, Sascha; Ropers, Claus

    2015-05-14

    Coherent manipulation of quantum systems with light is expected to be a cornerstone of future information and communication technology, including quantum computation and cryptography. The transfer of an optical phase onto a quantum wavefunction is a defining aspect of coherent interactions and forms the basis of quantum state preparation, synchronization and metrology. Light-phase-modulated electron states near atoms and molecules are essential for the techniques of attosecond science, including the generation of extreme-ultraviolet pulses and orbital tomography. In contrast, the quantum-coherent phase-modulation of energetic free-electron beams has not been demonstrated, although it promises direct access to ultrafast imaging and spectroscopy with tailored electron pulses on the attosecond scale. Here we demonstrate the coherent quantum state manipulation of free-electron populations in an electron microscope beam. We employ the interaction of ultrashort electron pulses with optical near-fields to induce Rabi oscillations in the populations of electron momentum states, observed as a function of the optical driving field. Excellent agreement with the scaling of an equal-Rabi multilevel quantum ladder is obtained, representing the observation of a light-driven 'quantum walk' coherently reshaping electron density in momentum space. We note that, after the interaction, the optically generated superposition of momentum states evolves into a train of attosecond electron pulses. Our results reveal the potential of quantum control for the precision structuring of electron densities, with possible applications ranging from ultrafast electron spectroscopy and microscopy to accelerator science and free-electron lasers.

  2. Modulational-instability gain bands in quasi-phase-matched materials

    International Nuclear Information System (INIS)

    Corney, J.F.; Bang, O.

    2002-01-01

    Full text: Quadratically nonlinear materials are of significant technological interest in optics because of their strong and fast cascaded nonlinearities, which are accessed most efficiently with quasi-phase-matching (QPM) techniques. We study the gain spectra of modulational instabilities (Ml) in quadratic materials where the linear and nonlinear properties are modulated with QPM gratings. The periods and intensity-dependence of the Ml can now be measured in the laboratory. Using an exact Floquet theory, we find that novel low- and high-frequency bands appear in the gain spectrum (gain versus transverse spatial frequency). The high-frequency gain bands are a general feature of gain spectra for QPM gratings. They form part of an extensive series of bands that correspond to Ml in the non-phase-matched, quickly varying components of the fields. The low-frequency bands correspond to Ml in the phase-matched DC components of the fields and are accurately predicted by a simple average theory. This theory includes the effect of the quickly varying components as induced cubic terms, which can be strong enough to suppress the low-frequency bands, in which case dark solitons and other broad beams may be effectively stable, since the high-frequency bands are typically small

  3. Programming Nanoparticles in Multiscale: Optically Modulated Assembly and Phase Switching of Silicon Nanoparticle Array.

    Science.gov (United States)

    Wang, Letian; Rho, Yoonsoo; Shou, Wan; Hong, Sukjoon; Kato, Kimihiko; Eliceiri, Matthew; Shi, Meng; Grigoropoulos, Costas P; Pan, Heng; Carraro, Carlo; Qi, Dongfeng

    2018-03-27

    Manipulating and tuning nanoparticles by means of optical field interactions is of key interest for nanoscience and applications in electronics and photonics. We report scalable, direct, and optically modulated writing of nanoparticle patterns (size, number, and location) of high precision using a pulsed nanosecond laser. The complex nanoparticle arrangement is modulated by the laser pulse energy and polarization with the particle size ranging from 60 to 330 nm. Furthermore, we report fast cooling-rate induced phase switching of crystalline Si nanoparticles to the amorphous state. Such phase switching has usually been observed in compound phase change materials like GeSbTe. The ensuing modification of atomic structure leads to dielectric constant switching. Based on these effects, a multiscale laser-assisted method of fabricating Mie resonator arrays is proposed. The number of Mie resonators, as well as the resonance peaks and dielectric constants of selected resonators, can be programmed. The programmable light-matter interaction serves as a mechanism to fabricate optical metasurfaces, structural color, and multidimensional optical storage devices.

  4. Ultrafast optical phase modulation with metallic nanoparticles in ion-implanted bilayer silica

    International Nuclear Information System (INIS)

    Torres-Torres, C; Tamayo-Rivera, L; Silva-Pereyra, H G; Reyes-Esqueda, J A; Rodriguez-Fernandez, L; Crespo-Sosa, A; Cheang-Wong, J C; Oliver, A; Rangel-Rojo, R; Torres-Martinez, R

    2011-01-01

    The nonlinear optical response of metallic-nanoparticle-containing composites was studied with picosecond and femtosecond pulses. Two different types of nanocomposites were prepared by an ion-implantation process, one containing Au nanoparticles (NPs) and the other Ag NPs. In order to measure the optical nonlinearities, we used a picosecond self-diffraction experiment and the femtosecond time-resolved optical Kerr gate technique. In both cases, electronic polarization and saturated absorption were identified as the physical mechanisms responsible for the picosecond third-order nonlinear response for a near-resonant 532 nm excitation. In contrast, a purely electronic nonlinearity was detected at 830 nm with non-resonant 80 fs pulses. Regarding the nonlinear optical refractive behavior, the Au nanocomposite presented a self-defocusing effect, while the Ag one presented the opposite, that is, a self-focusing response. But, when evaluating the simultaneous contributions when the samples are tested as a multilayer sample (silica-Au NPs-silica-Ag NPs-silica), we were able to obtain optical phase modulation of ultra-short laser pulses, as a result of a significant optical Kerr effect present in these nanocomposites. This allowed us to implement an ultrafast all-optical phase modulator device by using a combination of two different metallic ion-implanted silica samples. This control of the optical phase is a consequence of the separate excitation of the nonlinear refracting phenomena exhibited by the separate Au and Ag nanocomposites.

  5. Cross-correlation of instantaneous phase increments in pressure-flow fluctuations: Applications to cerebral autoregulation

    Science.gov (United States)

    Chen, Zhi; Hu, Kun; Stanley, H. Eugene; Novak, Vera; Ivanov, Plamen Ch.

    2006-03-01

    We investigate the relationship between the blood flow velocities (BFV) in the middle cerebral arteries and beat-to-beat blood pressure (BP) recorded from a finger in healthy and post-stroke subjects during the quasisteady state after perturbation for four different physiologic conditions: supine rest, head-up tilt, hyperventilation, and CO2 rebreathing in upright position. To evaluate whether instantaneous BP changes in the steady state are coupled with instantaneous changes in the BFV, we compare dynamical patterns in the instantaneous phases of these signals, obtained from the Hilbert transform, as a function of time. We find that in post-stroke subjects the instantaneous phase increments of BP and BFV exhibit well-pronounced patterns that remain stable in time for all four physiologic conditions, while in healthy subjects these patterns are different, less pronounced, and more variable. We propose an approach based on the cross-correlation of the instantaneous phase increments to quantify the coupling between BP and BFV signals. We find that the maximum correlation strength is different for the two groups and for the different conditions. For healthy subjects the amplitude of the cross-correlation between the instantaneous phase increments of BP and BFV is small and attenuates within 3-5 heartbeats. In contrast, for post-stroke subjects, this amplitude is significantly larger and cross-correlations persist up to 20 heartbeats. Further, we show that the instantaneous phase increments of BP and BFV are cross-correlated even within a single heartbeat cycle. We compare the results of our approach with three complementary methods: direct BP-BFV cross-correlation, transfer function analysis, and phase synchronization analysis. Our findings provide insight into the mechanism of cerebral vascular control in healthy subjects, suggesting that this control mechanism may involve rapid adjustments (within a heartbeat) of the cerebral vessels, so that BFV remains steady in

  6. A new phase modulated binomial-like selective-inversion sequence for solvent signal suppression in NMR.

    Science.gov (United States)

    Chen, Johnny; Zheng, Gang; Price, William S

    2017-02-01

    A new 8-pulse Phase Modulated binomial-like selective inversion pulse sequence, dubbed '8PM', was developed by optimizing the nutation and phase angles of the constituent radio-frequency pulses so that the inversion profile resembled a target profile. Suppression profiles were obtained for both the 8PM and W5 based excitation sculpting sequences with equal inter-pulse delays. Significant distortions were observed in both profiles because of the offset effect of the radio frequency pulses. These distortions were successfully reduced by adjusting the inter-pulse delays. With adjusted inter-pulse delays, the 8PM and W5 based excitation sculpting sequences were tested on an aqueous lysozyme solution. The 8 PM based sequence provided higher suppression selectivity than the W5 based sequence. Two-dimensional nuclear Overhauser effect spectroscopy experiments were also performed on the lysozyme sample with 8PM and W5 based water signal suppression. The 8PM based suppression provided a spectrum with significantly increased (~ doubled) cross-peak intensity around the suppressed water resonance compared to the W5 based suppression. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  7. Probing exotic phases of interacting two-dimensional carriers using one-dimensional density modulation

    Science.gov (United States)

    Mueed, M. A.

    nature of the interacting bilayer system at nu=1 and 1/2. Finally, we focus on the half filling of a higher Landau level, namely nu=7/2, where B|| induces an anisotropic stripe phase. We show that a minute external density modulation is sufficient to cause a reorientation of the stripe phase if its wavelength is comparable to the external modulation period.

  8. PHASE QUANTIZATION STUDY OF SPATIAL LIGHT MODULATOR FOR EXTREME HIGH-CONTRAST IMAGING

    Energy Technology Data Exchange (ETDEWEB)

    Dou, Jiangpei; Ren, Deqing, E-mail: jpdou@niaot.ac.cn, E-mail: jiangpeidou@gmail.com [Physics and Astronomy Department, California State University Northridge, 18111 Nordhoff Street, Northridge, CA 91330 (United States)

    2016-11-20

    Direct imaging of exoplanets by reflected starlight is extremely challenging due to the large luminosity ratio to the primary star. Wave-front control is a critical technique to attenuate the speckle noise in order to achieve an extremely high contrast. We present a phase quantization study of a spatial light modulator (SLM) for wave-front control to meet the contrast requirement of detection of a terrestrial planet in the habitable zone of a solar-type star. We perform the numerical simulation by employing the SLM with different phase accuracy and actuator numbers, which are related to the achievable contrast. We use an optimization algorithm to solve the quantization problems that is matched to the controllable phase step of the SLM. Two optical configurations are discussed with the SLM located before and after the coronagraph focal plane mask. The simulation result has constrained the specification for SLM phase accuracy in the above two optical configurations, which gives us a phase accuracy of 0.4/1000 and 1/1000 waves to achieve a contrast of 10{sup -10}. Finally, we have demonstrated that an SLM with more actuators can deliver a competitive contrast performance on the order of 10{sup -10} in comparison to that by using a deformable mirror.

  9. Smectic-like phase for modulated XY spins in two dimensions

    International Nuclear Information System (INIS)

    Benakli, M.; Gabay, M.; Saslow, W.M.

    1997-09-01

    The row model for frustrated XY spins on a triangular lattice in 2D is used to study incommensurate (IC) and commensurate (C) phases, in the regime where a (C)-(IC) transition may be observed. Thermodynamic quantities for the (IC) state are computed analytically by means of the NSCHA, a new variational method appropriate for frustrated systems. On the commensurate side of the (C)-(IC) boundary, NSCHA predicts an instability of the (C) phase suggesting that this state is in fact spatially inhomogeneous. Detailed Monte-Carlo (MC) simulations using fluctuating boundary conditions and specific histogram techniques show that in this regime the configuration consists of stripes of (C) and (IC) phases alternating in space. This state, which resembles the smectic-A phase of liquid crystals, exists because of the strong coupling between chiral and phase (spin angle) variables. As a result, the transition between the (IC) and the (C) states can only occur at zero temperature T so that the Lifshitz point is at T = 0 for modulated XY spins in 2D. (author)

  10. Gas-phase photoemission with soft x-rays: cross sections and angular distributions

    International Nuclear Information System (INIS)

    Shirley, D.A.; Kobrin, P.H.; Truesdale, C.M.; Lindle, D.W.; Ferrett, T.A.; Heimann, P.A.; Becker, U.; Kerkhoff, H.G.; Southworth, S.H.

    1983-09-01

    A summary is presented of typical gas-phase photoemission studies based on synchrotron radiation in the 50-5000 eV range, using beam lines at the Stanford Synchrotron Radiation Laboratory. Three topics are addressed: atomic inner-shell photoelectron cross sections and asymmetries, correlation peaks in rare gases, and core-level shape resonances in molecules

  11. Crossing the Gap between Indigenous Worldview and Western Science: Millet Festival as a Bridge in the Teaching Module

    Science.gov (United States)

    Chiang, Chia-Ling; Lee, Huei

    2015-01-01

    The worldview within indigenous people's traditional knowledge and western science can be a world of difference. In order to help indigenous students cross the gap and develop a sense of cultural identification. Taking Bunun, one of the Taiwanese indigenous tribes, as our subject, this study aims to develop a teaching module through Bunun's Millet…

  12. Phase modulation spectroscopy of space-charge wave resonances in Bi12SiO20

    DEFF Research Database (Denmark)

    Vasnetsov, M.; Buchhave, Preben; Lyuksyutov, S.

    1997-01-01

    A new experimental method for the study of resonance effects and space-charge wave excitation in photorefractive Bi12SiO20 crystals by using a combination of frequency detuning and phase modulation technique has been developed. The accuracy of the method allows a detection of resonance peaks...... of diffraction efficiency within 0.5 Hz. Numerical simulations of the nonlinear differential equations describing the behaviour of the space-charge waves in photorefractive crystals have been performed and found to be in a good agreement with experiment. We have measured the photocurrent through the crystal...

  13. Self-phase modulation of a single-cycle THz pulse

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hvam, Jørn Märcher; Hoffmann, M. C.

    2013-01-01

    We demonstrate self-phase modulation (SPM) of a single-cycle THz pulse in a semiconductor, using bulk n-GaAs as a model system. The SPM arises from the heating of free electrons in the electric field of the THz pulse. Electron heating leads to an ultrafast reduction of the plasma frequency, which...... results in a strong modification of the THz-range dielectric function of the material. THz SPM is observed directly in the time domain as a characteristic reshaping of single-cycle THz pulse. In the frequency domain, it corresponds to a strong frequency-dependent refractive index nonlinearity of n...

  14. Input-dependent frequency modulation of cortical gamma oscillations shapes spatial synchronization and enables phase coding.

    Science.gov (United States)

    Lowet, Eric; Roberts, Mark; Hadjipapas, Avgis; Peter, Alina; van der Eerden, Jan; De Weerd, Peter

    2015-02-01

    Fine-scale temporal organization of cortical activity in the gamma range (∼25-80Hz) may play a significant role in information processing, for example by neural grouping ('binding') and phase coding. Recent experimental studies have shown that the precise frequency of gamma oscillations varies with input drive (e.g. visual contrast) and that it can differ among nearby cortical locations. This has challenged theories assuming widespread gamma synchronization at a fixed common frequency. In the present study, we investigated which principles govern gamma synchronization in the presence of input-dependent frequency modulations and whether they are detrimental for meaningful input-dependent gamma-mediated temporal organization. To this aim, we constructed a biophysically realistic excitatory-inhibitory network able to express different oscillation frequencies at nearby spatial locations. Similarly to cortical networks, the model was topographically organized with spatially local connectivity and spatially-varying input drive. We analyzed gamma synchronization with respect to phase-locking, phase-relations and frequency differences, and quantified the stimulus-related information represented by gamma phase and frequency. By stepwise simplification of our models, we found that the gamma-mediated temporal organization could be reduced to basic synchronization principles of weakly coupled oscillators, where input drive determines the intrinsic (natural) frequency of oscillators. The gamma phase-locking, the precise phase relation and the emergent (measurable) frequencies were determined by two principal factors: the detuning (intrinsic frequency difference, i.e. local input difference) and the coupling strength. In addition to frequency coding, gamma phase contained complementary stimulus information. Crucially, the phase code reflected input differences, but not the absolute input level. This property of relative input-to-phase conversion, contrasting with latency codes

  15. Two-Phase Gas-Liquid Flow Structure Characteristics under Periodic Cross Forces Action

    Directory of Open Access Journals (Sweden)

    V. V. Perevezentsev

    2015-01-01

    Full Text Available The article presents a study of two-phase gas-liquid flow under the action of periodic cross forces. The work objective is to obtain experimental data for further analysis and have structure characteristics of the two-phase flow movement. For research, to obtain data without disturbing effect on the flow were used optic PIV (Particle Image Visualization methods because of their noninvasiveness. The cross forces influence was provided by an experimental stand design to change the angular amplitudes and the periods of channel movement cycle with two-phase flow. In the range of volume gas rates was shown a water flow rate versus the inclination angle of immovable riser section and the characteristic angular amplitudes and periods of riser section inclination cycle under periodic cross forces. Data on distribution of average water velocity in twophase flow in abovementioned cases were also obtained. These data allowed us to draw a conclusion that a velocity distribution depends on the angular amplitude and on the period of the riser section roll cycle. This article belongs to publications, which study two-phase flows with no disturbing effect on them. Obtained data give an insight into understanding a pattern of twophase gas-liquid flow under the action of periodic cross forces and can be used to verify the mathematical models of the CFD thermo-hydraulic codes. In the future, the work development expects taking measurements with more frequent interval in the ranges of angular amplitudes and periods of the channel movement cycle and create a mathematical model to show the action of periodic cross forces on two-phase gas-liquid flow.

  16. Two benchmark cases for the trio two-phase flow module

    Energy Technology Data Exchange (ETDEWEB)

    Helton, D.; Hassan, Y. [Texas A and M University, Nuclear Engineering Dept., College Station, Texas (United States); Kumbaro, A. [CEA Saclay, 91 - Gif-sur-Yvette (France). Dept. de Mecanique et de Technologie

    2001-07-01

    This report presents a series of problems that were studied in order to assess the new implementations recently made to the two-phase flow module. Each problem is designed to give insight into a particular area of the code refinement. As such, each problem, and its corresponding results will be discussed individually, with comparisons made to experimental or analytical results whenever possible. TrioU is a thermal hydraulics program created by CEA. It is currently evolving in to a multi-dimensional, multi-fluid, multi-phase program. The purpose of TrioU is to provide a platform for testing of new numerical methods and physical models that are developed by the Nuclear Reactor Division of CEA. TrioU is written in an object-oriented programming language, and maintained by a version-controllable environment, for ease in parallelization and multiple-site development. (author)

  17. Two benchmark cases for the trio two-phase flow module

    International Nuclear Information System (INIS)

    Helton, D.; Hassan, Y.; Kumbaro, A.

    2001-01-01

    This report presents a series of problems that were studied in order to assess the new implementations recently made to the two-phase flow module. Each problem is designed to give insight into a particular area of the code refinement. As such, each problem, and its corresponding results will be discussed individually, with comparisons made to experimental or analytical results whenever possible. TrioU is a thermal hydraulics program created by CEA. It is currently evolving in to a multi-dimensional, multi-fluid, multi-phase program. The purpose of TrioU is to provide a platform for testing of new numerical methods and physical models that are developed by the Nuclear Reactor Division of CEA. TrioU is written in an object-oriented programming language, and maintained by a version-controllable environment, for ease in parallelization and multiple-site development. (author)

  18. Phase-sensitive detection of optical resonances by using an acousto-optic modulator in the Raman - Nath diffraction mode

    International Nuclear Information System (INIS)

    Baryshev, V N; Domnin, Yu S; Kopylov, L N

    2007-01-01

    A new method for frequency control of an external cavity diode laser without direct modulation of the injection current is proposed. The Pound - Drever optical heterodyne technique or the method of frequency control by frequency-modulated sidebands, in which an acousto-optic modulator operating in the Raman - Nath diffraction mode is used as an external phase modulator, can be employed to obtain error signals upon automatic frequency locking of the diode laser to the saturated absorption resonances within the D 2 line of cesium atoms or to the optical cavity resonances. (control of laser radiation parameters)

  19. Development of OCDMA system based on Flexible Cross Correlation (FCC) code with OFDM modulation

    Science.gov (United States)

    Aldhaibani, A. O.; Aljunid, S. A.; Anuar, M. S.; Arief, A. R.; Rashidi, C. B. M.

    2015-03-01

    The performance of the OCDMA systems is governed by numerous quantitative parameters such as the data rate, simultaneous number of users, the powers of transmitter and receiver, and the type of codes. This paper analyzes the performance of the OCDMA system using OFDM technique to enhance the channel data rate, to save power and increase the number of user of OSCDMA systems compared with previous hybrid subcarrier multiplexing/optical spectrum code division multiplexing (SCM/OSCDM) system. The average received signal to noise ratio (SNR) with the nonlinearity of subcarriers is derived. The theoretical results have been evaluated based on BER and number of users as well as amount of power saved. The proposed system gave better performance and save around -6 dBm of the power as well as increase the number of users twice compare to SCM/OCDMA system. In addition it is robust against interference and much more spectrally efficient than SCM/OCDMA system. The system was designed based on Flexible Cross Correlation (FCC) code which is easier construction, less complexity of encoder/decoder design and flexible in-phase cross-correlation for uncomplicated to implement using Fiber Bragg Gratings (FBGs) for the OCDMA systems for any number of users and weights. The OCDMA-FCC_OFDM improves the number of users (cardinality) 108% compare to SCM/ODCMA-FCC system.

  20. Optical-wireless-optical full link for polarization multiplexing quadrature amplitude/phase modulation signal transmission.

    Science.gov (United States)

    Li, Xinying; Yu, Jianjun; Chi, Nan; Zhang, Junwen

    2013-11-15

    We propose and experimentally demonstrate an optical wireless integration system at the Q-band, in which up to 40 Gb/s polarization multiplexing multilevel quadrature amplitude/phase modulation (PM-QAM) signal can be first transmitted over 20 km single-mode fiber-28 (SMF-28), then delivered over a 2 m 2 × 2 multiple-input multiple-output wireless link, and finally transmitted over another 20 km SMF-28. The PM-QAM modulated wireless millimeter-wave (mm-wave) signal at 40 GHz is generated based on the remote heterodyning technique, and demodulated by the radio-frequency transparent photonic technique based on homodyne coherent detection and baseband digital signal processing. The classic constant modulus algorithm equalization is used at the receiver to realize polarization demultiplexing of the PM-QAM signal. For the first time, to the best of our knowledge, we realize the conversion of the PM-QAM modulated wireless mm-wave signal to the optical signal as well as 20 km fiber transmission of the converted optical signal.

  1. Using Real-Worldness and Cultural Difference to Enhance Student Learning in a Foundation Phase Life Skills Module

    Science.gov (United States)

    Koen, Mariette; Ebrahim, Hasina Banu

    2013-01-01

    Our aim was to explore how real-world experience, inclusive of engagement with cultural differences, influences the quality of students' learning in a Life Skills module in pre-service Foundation Phase teacher education. The study was conducted with 147 students in their final year of the Bachelor of Education (Foundation Phase specialisation), at…

  2. Utilization of a liquid crystal spatial light modulator in a gray scale detour phase method for Fourier holograms.

    Science.gov (United States)

    Makey, Ghaith; El-Daher, Moustafa Sayem; Al-Shufi, Kanj

    2012-11-10

    This paper introduces a new modification for the well-known binary detour phase method, which is largely used to represent Fourier holograms; the modification utilizes gray scale level control provided by a liquid crystal spatial light modulator to improve the traditional binary detour phase. Results are shown by both simulation and experiment.

  3. Brazilian cross-cultural adaptation of the DocCom online module: communication for teamwork 1

    Science.gov (United States)

    Borges, Tatiane Angélica Phelipini; Vannuchi, Marli Terezinha Oliveira; Grosseman, Suely; González, Alberto Durán

    2017-01-01

    ABSTRACT Objective: to carry out the cross-cultural adaptation of DocCom online module 38, which deals with teamwork communication into Portuguese for the Brazilian contexto. Method: the transcultural translation and adaptation were accomplished through initial translations, synthesis of the translations, evaluation and synthesis by a committee of experts, analysis by translators and back translation, pre-test with nurses and undergraduate students in Nursing, and analysis of the translators to obtain the final material. Results: in evaluation and synthesis of the translated version with the original version by the expert committee, the items obtained higher than 80% agreement. Few modifications were suggested according to the analysis by pretest participants. The final version was adequate to the proposed context and its purpose. Conclusion: it is believed that by making this new teaching-learning strategy of communication skills and competencies for teamwork available, it can be used systematically in undergraduate and postgraduate courses in the health area in Brazil in order to contribute to training professionals, and also towards making advances in this field.

  4. Brazilian cross-cultural adaptation of the DocCom online module: communication for teamwork

    Directory of Open Access Journals (Sweden)

    Tatiane Angélica Phelipini Borges

    2017-09-01

    Full Text Available ABSTRACT Objective: to carry out the cross-cultural adaptation of DocCom online module 38, which deals with teamwork communication into Portuguese for the Brazilian contexto. Method: the transcultural translation and adaptation were accomplished through initial translations, synthesis of the translations, evaluation and synthesis by a committee of experts, analysis by translators and back translation, pre-test with nurses and undergraduate students in Nursing, and analysis of the translators to obtain the final material. Results: in evaluation and synthesis of the translated version with the original version by the expert committee, the items obtained higher than 80% agreement. Few modifications were suggested according to the analysis by pretest participants. The final version was adequate to the proposed context and its purpose. Conclusion: it is believed that by making this new teaching-learning strategy of communication skills and competencies for teamwork available, it can be used systematically in undergraduate and postgraduate courses in the health area in Brazil in order to contribute to training professionals, and also towards making advances in this field.

  5. Perceptual complexity of faces and voices modulates cross-modal behavioral facilitation effects

    Directory of Open Access Journals (Sweden)

    Frédéric Joassin

    2018-04-01

    Full Text Available Joassin et al. (Neuroscience Letters, 2004,369,132-137 observed that the recognition of face-voice associations led to an interference effect, i.e. to decreased performances relative to the recognition of faces presented in isolation. In the present experiment, we tested the hypothesis that this interference effect could be due to the fact that voices were more difficult to recognize than faces. For this purpose, we modified some faces by morphing to make them as difficult to recognize as the voices. Twenty one healthy volunteers performed a recogniton task of previously learned face-voice associations in 5 conditions: voices (A, natural faces (V, morphed faces (V30, voice-natural face associations (AV and voice-morphed faces associations (AV30. As expected, AV led to interference, as it was less well and slower performed than V. However, when faces were as difficult to recognize as voices, their simultaneous presentation produced a clear facilitation, AV30 being significantly better and faster performed than A and V30. These results demonstrate that matching or not the perceptual complexity of the unimodal stimuli modulates the potential cross-modal gains of the bimodal situations.

  6. Resource Availability Modulates the Cooperative and Competitive Nature of a Microbial Cross-Feeding Mutualism.

    Directory of Open Access Journals (Sweden)

    Tim A Hoek

    2016-08-01

    Full Text Available Mutualisms between species play an important role in ecosystem function and stability. However, in some environments, the competitive aspects of an interaction may dominate the mutualistic aspects. Although these transitions could have far-reaching implications, it has been difficult to study the causes and consequences of this mutualistic-competitive transition in experimentally tractable systems. Here, we study a microbial cross-feeding mutualism in which each yeast strain supplies an essential amino acid for its partner strain. We find that, depending upon the amount of freely available amino acid in the environment, this pair of strains can exhibit an obligatory mutualism, facultative mutualism, competition, parasitism, competitive exclusion, or failed mutualism leading to extinction of the population. A simple model capturing the essential features of this interaction explains how resource availability modulates the interaction and predicts that changes in the dynamics of the mutualism in deteriorating environments can provide advance warning that collapse of the mutualism is imminent. We confirm this prediction experimentally by showing that, in the high nutrient competitive regime, the strains rapidly reach a common carrying capacity before slowly reaching the equilibrium ratio between the strains. However, in the low nutrient regime, before collapse of the obligate mutualism, we find that the ratio rapidly reaches its equilibrium and it is the total abundance that is slow to reach equilibrium. Our results provide a general framework for how mutualisms may transition between qualitatively different regimes of interaction in response to changes in nutrient availability in the environment.

  7. Phase Clustering Based Modulation Classification Algorithm for PSK Signal over Wireless Environment

    Directory of Open Access Journals (Sweden)

    Qi An

    2016-01-01

    Full Text Available Promptitude and accuracy of signals’ non-data-aided (NDA identification is one of the key technology demands in noncooperative wireless communication network, especially in information monitoring and other electronic warfare. Based on this background, this paper proposes a new signal classifier for phase shift keying (PSK signals. The periodicity of signal’s phase is utilized as the assorted character, with which a fractional function is constituted for phase clustering. Classification and the modulation order of intercepted signals can be achieved through its Fast Fourier Transform (FFT of the phase clustering function. Frequency offset is also considered for practical conditions. The accuracy of frequency offset estimation has a direct impact on its correction. Thus, a feasible solution is supplied. In this paper, an advanced estimator is proposed for estimating the frequency offset and balancing estimation accuracy and range under low signal-to-noise ratio (SNR conditions. The influence on estimation range brought by the maximum correlation interval is removed through the differential operation of the autocorrelation of the normalized baseband signal raised to the power of Q. Then, a weighted summation is adopted for an effective frequency estimation. Details of equations and relevant simulations are subsequently presented. The estimator proposed can reach an estimation accuracy of 10-4 even when the SNR is as low as -15 dB. Analytical formulas are expressed, and the corresponding simulations illustrate that the classifier proposed is more efficient than its counterparts even at low SNRs.

  8. Characterisation of different single and multilayer films using phase modulated spectroscopic ellipsometry

    International Nuclear Information System (INIS)

    Das, N.C.; Bhattacharyya, D.; Thakur, S.

    1998-06-01

    Different single layers and multilayer coatings deposited by e-beam evaporation and r.f. sputtering techniques have been characterised by the Phase Modulated Spectroscopic Ellipsometer, installed recently in the Spectroscopy Division, B.A.R.C. The Phase Modulated technique provides a faster and more accurate data acquisition process than the conventional ellipsometry. Measurements have been done on single layers of Cu, Si and ZrO 2 films and on multilayer thin films devices e.g., high reflectivity mirror, beam combiner, beam splitter, narrow band filter etc. consisting of several bilayers of TiO 2 /SiO 2 . The measured Ellipsometry spectra is then fitted with a theoretical spectra generated assuming an appropriate model regarding the sample. The layer thickness and composition have been used as fitting parameters. The optical constants of the substrates have been supplied and a trial dispersion relation have been used for the layers. In case of inhomogeneous layers, trial compositions have been given for the individual components for each layer. The roughness of the layers has been taken into account by assuming the film to be an inhomogeneous mixture of material and voids. The fittings have been done objectively by minimising the squared difference (χ 2 ) between the measured and calculated values of the ellipsometric parameters and thus accurate information have been derived regarding the thickness and optical constants (viz, the refractive index and extinction coefficient) of the different layers, the surface roughness and the inhomogeneities present in the layers. (author)

  9. Modulating the amplitude and phase of the complex spectral degree of coherence with plasmonic interferometry

    Science.gov (United States)

    Li, Dongfang; Pacifici, Domenico

    The spectral degree of coherence describes the correlation of electromagnetic fields, which plays a key role in many applications, including free-space optical communications and speckle-free bioimaging. Recently, plasmonic interferometry, i.e. optical interferometry that employs surface plasmon polaritons (SPPs), has enabled enhanced light transmission and high-sensitivity biosensing, among other applications. It offers new ways to characterize and engineer electromagnetic fields using nano-structured thin metal films. Here, we employ plasmonic interferometry to demonstrate full control of spatial coherence at length scales comparable to the wavelength of the incident light. Specifically, by measuring the diffraction pattern of several double-slit plasmonic structures etched on a metal film, the amplitude and phase of the degree of spatial coherence is determined as a function of slit-slit separation distance and incident wavelength. When the SPP contribution is turned on (i.e., by changing the polarization of the incident light from TE to TM illumination mode), strong modulation of both amplitude and phase of the spatial coherence is observed. These findings may help design compact modulators of optical spatial coherence and other optical elements to shape the light intensity in the far-field.

  10. Sequential attack with intensity modulation on the differential-phase-shift quantum-key-distribution protocol

    International Nuclear Information System (INIS)

    Tsurumaru, Toyohiro

    2007-01-01

    In this paper, we discuss the security of the differential-phase-shift quantum-key-distribution (DPSQKD) protocol by introducing an improved version of the so-called sequential attack, which was originally discussed by Waks et al. [Phys. Rev. A 73, 012344 (2006)]. Our attack differs from the original form of the sequential attack in that the attacker Eve modulates not only the phases but also the amplitude in the superposition of the single-photon states which she sends to the receiver. Concentrating especially on the 'discretized Gaussian' intensity modulation, we show that our attack is more effective than the individual attack, which had been the best attack up to present. As a result of this, the recent experiment with communication distance of 100 km reported by Diamanti et al. [Opt. Express 14, 13073 (2006)] turns out to be insecure. Moreover, it can be shown that in a practical experimental setup which is commonly used today, the communication distance achievable by the DPSQKD protocol is less than 95 km

  11. Aerosol absorption measurement with a sinusoidal phase modulating fiber optic photo thermal interferometer

    Science.gov (United States)

    Li, Shuwang; Shao, Shiyong; Mei, Haiping; Rao, Ruizhong

    2016-10-01

    Aerosol light absorption plays an important role in the earth's atmosphere direct and semi-direct radiate forcing, simultaneously, it also has a huge influence on the visibility impairment and laser engineering application. Although various methods have been developed for measuring aerosol light absorption, huge challenge still remains in precision, accuracy and temporal resolution. The main reason is that, as a part of aerosol light extinction, aerosol light absorption always generates synchronously with aerosol light scattering, and unfortunately aerosol light scattering is much stronger in most cases. Here, a novel photo-thermal interferometry is proposed only for aerosol absorption measurement without disturbance from aerosol scattering. The photo-thermal interferometry consists of a sinusoidal phase-modulating single mode fiber-optic interferometer. The thermal dissipation, caused by aerosol energy from photo-thermal conversion when irritated by pump laser through interferometer, is detected. This approach is completely insensitive to aerosol scattering, and the single mode fiber-optic interferometer is compact, low-cost and insensitive to the polarization shading. The theory of this technique is illustrated, followed by the basic structure of the sinusoidal phase-modulating fiber-optic interferometer and demodulation algorithms. Qualitative and quantitative analysis results show that the new photo-thermal interference is a potential approach for aerosol absorption detection and environmental pollution detection.

  12. Double closed-loop resonant micro optic gyro using hybrid digital phase modulation.

    Science.gov (United States)

    Ma, Huilian; Zhang, Jianjie; Wang, Linglan; Jin, Zhonghe

    2015-06-15

    It is well-known that the closed-loop operation in optical gyros offers wider dynamic range and better linearity. By adding a stair-like digital serrodyne wave to a phase modulator can be used as a frequency shifter. The width of one stair in this stair-like digital serrodyne wave should be set equal to the optical transmission time in the resonator, which is relaxed in the hybrid digital phase modulation (HDPM) scheme. The physical mechanism for this relaxation is firstly indicated in this paper. Detailed theoretical and experimental investigations are presented for the HDPM. Simulation and experimental results show that the width of one stair is not restricted by the optical transmission time, however, it should be optimized according to the rise time of the output of the digital-to-analogue converter. Based on the optimum parameters of the HDPM, a bias stability of 0.05°/s for the integration time of 400 seconds in 1 h has been carried out in an RMOG with a waveguide ring resonator with a length of 7.9 cm and a diameter of 2.5 cm.

  13. Emerging technologies and approaches to minimize discharges into Lake Michigan Phase 2, Module 3 report.

    Energy Technology Data Exchange (ETDEWEB)

    Negri, M. C.; Gillenwater, P.; Urgun Demirtas, M. (Energy Systems)

    2011-05-11

    Purdue University Calumet (Purdue) and Argonne National Laboratory (Argonne) have conducted an independent study to identify deployable technologies that could help the BP Whiting Refinery, and other petroleum refineries, meet future wastewater discharge limits. This study has been funded by BP. Each organization tested a subset of the target technologies and retains sole responsibility for its respective test design and implementation, quality assurance and control, test results obtained from each of the technologies, and corresponding conclusions and recommendations. This project was divided in two phases and modules. This report summarizes the work conducted by Argonne in Phase II Module 3 (Bench Scale Testing). Other Modules are discussed elsewhere (Emerging Technologies and Approaches to Minimize Discharges into Lake Michigan, Phase 2, Modules 1-3 Report, April 2011, prepared for BP Americas by the Argonne - Purdue Task Force). The goal of this project was to identify and assess available and emerging wastewater treatment technologies for removing mercury and vanadium from the Whiting Refinery wastewater and to conduct bench-scale tests to provide comparable, transparent, and uniform results across the broad range of technologies tested. After the bench-scale testing phase, a previously developed decision matrix was refined and applied by Argonne to process and review test data to estimate and compare the preliminary performance, engineering configuration, preliminary cost, energy usage, and waste generation of technologies that were shown to be able to remove Hg and/or V to below the target limit at the bench scale. The data were used as the basis to identify the best candidates for further testing at the bench or pilot scale on a slip stream of effluent to lake (ETL) or clarifier effluent (CE) at the Whiting Refinery to determine whether future limits could be met and to generate other pertinent data for scale-up and sustainability evaluation. As a result of

  14. Batching alternatives for Phase I retrieval wastes to be processed in WRAP Module 1

    International Nuclear Information System (INIS)

    Mayancsik, B.A.

    1994-01-01

    During the next two decades, the transuranic (TRU) waste now stored in the 200 Area burial trenches and storage buildings is to be retrieved, processed in the Waste Receiving and Processing (WRAP) Module 1 facility, and shipped to a final disposal facility. The purpose of this document is to identify the criteria that can be used to batch suspect TRU waste, currently in retrievable storage, for processing through the WRAP Module 1 facility. These criteria are then used to generate a batch plan for Phase 1 Retrieval operations, which will retrieve the waste located in Trench 4C-04 of the 200 West Area burial ground. The reasons for batching wastes for processing in WRAP Module 1 include reducing the exposure of workers and the environment to hazardous material and ionizing radiation; maximizing the efficiency of the retrieval, processing, and disposal processes by reducing costs, time, and space throughout the process; reducing analytical sampling and analysis; and reducing the amount of cleanup and decontamination between process runs. The criteria selected for batching the drums of retrieved waste entering WRAP Module 1 are based on the available records for the wastes sent to storage as well as knowledge of the processes that generated these wastes. The batching criteria identified in this document include the following: waste generator; type of process used to generate or package the waste; physical waste form; content of hazardous/dangerous chemicals in the waste; radiochemical type and quantity of waste; drum weight; and special waste types. These criteria were applied to the waste drums currently stored in Trench 4C-04. At least one batching scheme is shown for each of the criteria listed above

  15. Investigation of the impact of mechanical stress on the properties of silicon sensor modules for the ATLAS Phase II upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Stegler, Martin; Polay, Luise; Spehrlich, Dennis; Bloch, Ingo [DESY, Zeuthen (Germany)

    2016-07-01

    The new ATLAS tracker for phase II will be composed of silicon pixel and strip sensor modules. Such a module consists of silicon sensors, boards and readout chips. In a currently ongoing study new adhesives to connect the modular components thermally and mechanically are examined. It was shown that the silicon sensor is exposed to mechanical stress when part of a module. Mechanical stress can cause damage to a sensor and can change the tensors of electrical properties. The study of the effects of mechanical stress on characteristics of the silicon sensor modules are the focus in this presentation. The thermal induced tensile stress near to the surface of a silicon sensor build in a module was simulated. A four point bending setup was used to measure the maximum tensile stress of silicon and to verify the piezoresistive effect on ATLAS07 sensors. The results of the electrical measurements and simulations of stressed silicon sensor modules are shown in the presentation.

  16. Fluid-elastic force measurements acting on a tube bundle in two-phase cross flow

    International Nuclear Information System (INIS)

    Inada, Fumio; Kawamura, Koji; Yasuo, Akira

    1996-01-01

    Fluid-elastic force acting on a square tube bundle of P/D = 1.47 in air-water two-phase cross flow was measured to investigate the characteristics and to clarify whether the fluid elastic vibration characteristics could be expressed using two-phase mixture characteristics. Measured fluid elastic forces were separated into fluid-elastic force coefficients such as added mass, added stiffness, and added damping coefficient. The added damping coefficient was separated into a two-phase damping and a flow-dependent component as in previous research (Carlucci, 1981 and 1983; Pettigrew, 1994). These coefficients were nondimensionalized with two-phase mixture characteristics such as void fraction, mixture density and mixture velocity, which were obtained using the drift-flux model with consideration given to the model. The result was compared with the result obtained with the homogeneous model. It was found that fluid-elastic force coefficients could be expressed with two-phase flow mixture characteristics very well in the experimental result, and that better result can be derived using the slip model as compared to the homogeneous model. Added two-phase flow, which could be expressed as a function of void fraction, where two-phase damping was nondimensionalized with the relative velocity between the gas and liquid phases used as a reference velocity. Using these, the added stiffness coefficient and flow-dependent component of damping could be expressed very well as a function of nondimensional mixture velocity

  17. Two-receiver measurements of phase velocity: cross-validation of ambient-noise and earthquake-based observations

    NARCIS (Netherlands)

    Kästle, Emanuel D.; Soomro, Riaz; Weemstra, C.; Boschi, Lapo; Meier, Thomas

    2016-01-01

    Phase velocities derived from ambient-noise cross-correlation are compared with phase velocities calculated from cross-correlations of waveform recordings of teleseismic earthquakes whose epicentres are approximately on the station–station great circle. The comparison is conducted both for Rayleigh

  18. Effect of realistic astrophysical inputs on the phase and shape of the weakly interacting massive particles annual modulation signal

    International Nuclear Information System (INIS)

    Green, Anne M.

    2003-01-01

    The orbit of the Earth about the Sun produces an annual modulation in the weakly interacting massive particles (WIMP) direct detection rate. If the local WIMP velocity distribution is isotropic then the modulation is roughly sinusoidal with maximum in June; however, if the velocity distribution is anisotropic the phase and shape of the signal can change. Motivated by conflicting claims about the effect of uncertainties in the local velocity distribution on the interpretation of the DAMA annual modulation signal (and the possibility that the form of the modulation could be used to probe the structure of the Milky Way halo), we study the dependence of the annual modulation on various astrophysical inputs. We first examine the approximations used for the Earth's motion about the Sun and the Sun's velocity with respect to the Galactic rest frame. We find that overly simplistic assumptions lead to errors of up to ten days in the phase and up to tens of percent in the shape of the signal, even if the velocity distribution is isotropic. Crucially, if the components of the Earth's velocity perpendicular to the motion of the Sun are neglected, then the change in the phase which occurs for anisotropic velocity distributions is missed. We then examine how the annual modulation signal varies for physically and observationally well-motivated velocity distributions. We find that the phase of the signal changes by up to 20 days and the mean value and amplitude change by up to tens of percent

  19. Dopamine Modulates Delta-Gamma Phase-Amplitude Coupling in the Prefrontal Cortex of Behaving Rats

    Science.gov (United States)

    Andino-Pavlovsky, Victoria; Souza, Annie C.; Scheffer-Teixeira, Robson; Tort, Adriano B. L.; Etchenique, Roberto; Ribeiro, Sidarta

    2017-01-01

    Dopamine release and phase-amplitude cross-frequency coupling (CFC) have independently been implicated in prefrontal cortex (PFC) functioning. To causally investigate whether dopamine release affects phase-amplitude comodulation between different frequencies in local field potentials (LFP) recorded from the medial PFC (mPFC) of behaving rats, we used RuBiDopa, a light-sensitive caged compound that releases the neurotransmitter dopamine when irradiated with visible light. LFP power did not change in any frequency band after the application of light-uncaged dopamine, but significantly strengthened phase-amplitude comodulation between delta and gamma oscillations. Saline did not exert significant changes, while injections of dopamine and RuBiDopa produced a slow increase in comodulation for several minutes after the injection. The results show that dopamine release in the medial PFC shifts phase-amplitude comodulation from theta-gamma to delta-gamma. Although being preliminary results due to the limitation of the low number of animals present in this study, our findings suggest that dopamine-mediated modification of the frequencies involved in comodulation could be a mechanism by which this neurotransmitter regulates functioning in mPFC. PMID:28536507

  20. Reducing mechanical cross-coupling in phased array transducers using stop band material as backing

    Science.gov (United States)

    Henneberg, J.; Gerlach, A.; Storck, H.; Cebulla, H.; Marburg, S.

    2018-06-01

    Phased array transducers are widely used for acoustic imaging and surround sensing applications. A major design challenge is the achievement of low mechanical cross-coupling between the single transducer elements. Cross-coupling induces a loss of imaging resolution. In this work, the mechanical cross-coupling between acoustic transducers is investigated for a generic model. The model contains a common backing with two bending elements bonded on top. The dimensions of the backing are small; thus, wave reflections on the backing edges have to be considered. This is different to other researches. The operating frequency in the generic model is set to a low kHz range. Low operating frequencies are typical for surround sensing applications. The influence of the backing on cross-coupling is investigated numerically. In order to reduce mechanical cross-coupling a stop band material is designed. It is shown numerically that a reduction in mechanical cross-coupling can be achieved by using stop band material as backing. The effect is validated with experimental testing.

  1. All-gas-phase synthesis of UiO-66 through modulated atomic layer deposition

    Science.gov (United States)

    Lausund, Kristian Blindheim; Nilsen, Ola

    2016-11-01

    Thin films of stable metal-organic frameworks (MOFs) such as UiO-66 have enormous application potential, for instance in microelectronics. However, all-gas-phase deposition techniques are currently not available for such MOFs. We here report on thin-film deposition of the thermally and chemically stable UiO-66 in an all-gas-phase process by the aid of atomic layer deposition (ALD). Sequential reactions of ZrCl4 and 1,4-benzenedicarboxylic acid produce amorphous organic-inorganic hybrid films that are subsequently crystallized to the UiO-66 structure by treatment in acetic acid vapour. We also introduce a new approach to control the stoichiometry between metal clusters and organic linkers by modulation of the ALD growth with additional acetic acid pulses. An all-gas-phase synthesis technique for UiO-66 could enable implementations in microelectronics that are not compatible with solvothermal synthesis. Since this technique is ALD-based, it could also give enhanced thickness control and the possibility to coat irregular substrates with high aspect ratios.

  2. Multi-kW coherent combining of fiber lasers seeded with pseudo random phase modulated light

    Science.gov (United States)

    Flores, Angel; Ehrehreich, Thomas; Holten, Roger; Anderson, Brian; Dajani, Iyad

    2016-03-01

    We report efficient coherent beam combining of five kilowatt-class fiber amplifiers with a diffractive optical element (DOE). Based on a master oscillator power amplifier (MOPA) configuration, the amplifiers were seeded with pseudo random phase modulated light. Each non-polarization maintaining fiber amplifier was optically path length matched and provides approximately 1.2 kW of near diffraction-limited output power (measured M2polarization control. A low power sample of the combined beam after the DOE provided an error signal for active phase locking which was performed via Locking of Optical Coherence by Single-Detector Electronic-Frequency Tagging (LOCSET). After phase stabilization, the beams were coherently combined via the 1x5 DOE. A total combined output power of 4.9 kW was achieved with 82% combining efficiency and excellent beam quality (M2splitter loss was 5%. Similarly, losses due in part to non-ideal polarization, ASE content, uncorrelated wavefront errors, and misalignment errors contributed to the efficiency reduction.

  3. Epileptic seizure detection from EEG signals with phase-amplitude cross-frequency coupling and support vector machine

    Science.gov (United States)

    Liu, Yang; Wang, Jiang; Cai, Lihui; Chen, Yingyuan; Qin, Yingmei

    2018-03-01

    As a pattern of cross-frequency coupling (CFC), phase-amplitude coupling (PAC) depicts the interaction between the phase and amplitude of distinct frequency bands from the same signal, and has been proved to be closely related to the brain’s cognitive and memory activities. This work utilized PAC and support vector machine (SVM) classifier to identify the epileptic seizures from electroencephalogram (EEG) data. The entropy-based modulation index (MI) matrixes are used to express the strength of PAC, from which we extracted features as the input for classifier. Based on the Bonn database, which contains five datasets of EEG segments obtained from healthy volunteers and epileptic subjects, a 100% classification accuracy is achieved for identifying seizure ictal from healthy data, and an accuracy of 97.67% is reached in the classification of ictal EEG signals from inter-ictal EEGs. Based on the CHB-MIT database which is a group of continuously recorded epileptic EEGs by scalp electrodes, a 97.50% classification accuracy is obtained and a raising sign of MI value is found at 6s before seizure onset. The classification performance in this work is effective, and PAC can be considered as a useful tool for detecting and predicting the epileptic seizures and providing reference for clinical diagnosis.

  4. Cross-Aldol condensation of isobutyraldehyde and formaldehyde using phase transfer catalyst

    Directory of Open Access Journals (Sweden)

    Azhar Hashmi

    2016-09-01

    Full Text Available The hydroxypivaldehyde (HPA precursor intermediate for the synthesis of neopentyl glycol (NPG is prepared by novel cross Aldol condensation of isobutyraldehyde and formaldehyde at 20 °C using benzyltrimethylammonium hydroxide, a basic phase transfer catalyst. A feed mole ratio of 1.1:1.0:0.04 (isobutyraldehyde:formaldehyde:benzyltrimethylammonium hydroxide afforded hydroxypivaldehyde as white solid in almost quantitative yield with ∼100% selectivity.

  5. Cross-Aldol condensation of isobutyraldehyde and formaldehyde using phase transfer catalyst

    OpenAIRE

    Azhar Hashmi

    2016-01-01

    The hydroxypivaldehyde (HPA) precursor intermediate for the synthesis of neopentyl glycol (NPG) is prepared by novel cross Aldol condensation of isobutyraldehyde and formaldehyde at 20 °C using benzyltrimethylammonium hydroxide, a basic phase transfer catalyst. A feed mole ratio of 1.1:1.0:0.04 (isobutyraldehyde:formaldehyde:benzyltrimethylammonium hydroxide) afforded hydroxypivaldehyde as white solid in almost quantitative yield with ∼100% selectivity.

  6. Approaching Pomeranchuk instabilities from ordered phase: A crossing-symmetric equation method

    International Nuclear Information System (INIS)

    Reidy, Kelly; Quader, Khandker; Bedell, Kevin

    2014-01-01

    We explore features of a 3D Fermi liquid near generalized Pomeranchuk instabilities using a tractable crossing-symmetric equation method. We approach the instabilities from the ordered ferromagnetic phase. We find “quantum multi-criticality” as approach to the ferromagnetic instability drives instability in other channel(s). It is found that a charge nematic instability precedes and is driven by Pomeranchuk instabilities in both the ℓ=0 spin and density channels

  7. 25 Gbit/s differential phase-shift-keying signal generation using directly modulated quantum-dot semiconductor optical amplifiers

    International Nuclear Information System (INIS)

    Zeghuzi, A.; Schmeckebier, H.; Stubenrauch, M.; Bimberg, D.; Meuer, C.; Schubert, C.; Bunge, C.-A.

    2015-01-01

    Error-free generation of 25-Gbit/s differential phase-shift keying (DPSK) signals via direct modulation of InAs quantum-dot (QD) based semiconductor optical amplifiers (SOAs) is experimentally demonstrated with an input power level of −5 dBm. The QD SOAs emit in the 1.3-μm wavelength range and provide a small-signal fiber-to-fiber gain of 8 dB. Furthermore, error-free DPSK modulation is achieved for constant optical input power levels from 3 dBm down to only −11 dBm for a bit rate of 20 Gbit/s. Direct phase modulation of QD SOAs via current changes is thus demonstrated to be much faster than direct gain modulation

  8. A 32-channel photon counting module with embedded auto/cross-correlators for real-time parallel fluorescence correlation spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gong, S.; Labanca, I.; Rech, I.; Ghioni, M. [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)

    2014-10-15

    Fluorescence correlation spectroscopy (FCS) is a well-established technique to study binding interactions or the diffusion of fluorescently labeled biomolecules in vitro and in vivo. Fast FCS experiments require parallel data acquisition and analysis which can be achieved by exploiting a multi-channel Single Photon Avalanche Diode (SPAD) array and a corresponding multi-input correlator. This paper reports a 32-channel FPGA based correlator able to perform 32 auto/cross-correlations simultaneously over a lag-time ranging from 10 ns up to 150 ms. The correlator is included in a 32 × 1 SPAD array module, providing a compact and flexible instrument for high throughput FCS experiments. However, some inherent features of SPAD arrays, namely afterpulsing and optical crosstalk effects, may introduce distortions in the measurement of auto- and cross-correlation functions. We investigated these limitations to assess their impact on the module and evaluate possible workarounds.

  9. A 32-channel photon counting module with embedded auto/cross-correlators for real-time parallel fluorescence correlation spectroscopy

    International Nuclear Information System (INIS)

    Gong, S.; Labanca, I.; Rech, I.; Ghioni, M.

    2014-01-01

    Fluorescence correlation spectroscopy (FCS) is a well-established technique to study binding interactions or the diffusion of fluorescently labeled biomolecules in vitro and in vivo. Fast FCS experiments require parallel data acquisition and analysis which can be achieved by exploiting a multi-channel Single Photon Avalanche Diode (SPAD) array and a corresponding multi-input correlator. This paper reports a 32-channel FPGA based correlator able to perform 32 auto/cross-correlations simultaneously over a lag-time ranging from 10 ns up to 150 ms. The correlator is included in a 32 × 1 SPAD array module, providing a compact and flexible instrument for high throughput FCS experiments. However, some inherent features of SPAD arrays, namely afterpulsing and optical crosstalk effects, may introduce distortions in the measurement of auto- and cross-correlation functions. We investigated these limitations to assess their impact on the module and evaluate possible workarounds

  10. Emerging technologies and approaches to minimize discharges into Lake Michigan, phase 2 module 4 report.

    Energy Technology Data Exchange (ETDEWEB)

    Negri, M.C.; Gillenwater, P.; Urgun-Demirtas, M.; Nnanna, G.; Yu, J.; Jannotta, I, (Energy Systems); (Purdue University Calumet)

    2012-04-19

    The Great Lakes Initiative (GLI) established the new water quality-based discharge criteria for mercury (Hg), thereby increasing the need for many municipal and industrial wastewater treatment plants in the region to lower the mercury in their effluents. Information on deployable technologies to satisfy these requirements for industrial and municipal dischargers in the Great lakes region is scarce. Therefore, BP funded Purdue University Calumet and Argonne to identify deployable Hg removal technologies to meet the GLI discharge criterion at its Whiting Refinery in Indiana. The joint PUC/Argonne project was divided into 2 phases. Results from Phase I and Phase II Modules 1-3 have been previously reported. This report summarizes the work done in Phase 3 Module 4, which consisted of the pilot scale testing of Hg removal technologies previously selected in Module 3. The pilot testing was an Argonne/PUC jointly directed project that was hosted at and funded by the BP refinery in Whiting, IN. As two organizations were involved in data analysis and interpretation, this report combines two independent sets of evaluations of the testing that was done, prepared respectively by Argonne and Purdue. Each organization retains sole responsibility for its respective analysis conclusions and recommendations. Based on Module 3 bench testing with pre-Effluent To Lake (pre-ETL) and clarifier effluent (CE) samples from the Whiting refinery, three different technologies were chosen for pilot testing: (1) Ultrafiltration (using GE ZeeWeed(reg sign) Technology, 0.04 {mu}m pore size and made up of PVDF) for particulate mercury removal; (2) Adsorption using Mersorb(reg sign) LW, a sulfur-impregnated activated carbon, for dissolved mercury removal if present and (3) The Blue PRO(reg sign) reactive filtration process for both particulate and dissolved (if present) mercury removal. The ultrafiltration and the Blue PRO(reg sign) reactive filtration pilot studies were done simultaneously at the

  11. Predictive Pulse Pattern Current Modulation Scheme for Harmonic Reduction in Three-Phase Multidrive Systems

    DEFF Research Database (Denmark)

    Davari, Pooya; Yang, Yongheng; Zare, Firuz

    2016-01-01

    at the rectification stage to synthesize sinusoidal input currents. The input voltage sensing is avoided in order to minimize the number of required sensors, and the grid synchronization also has been implemented based on a common Phase-Locked-Loop (PLL) using the DC-link capacitor voltage ripple. Experimental results......The majority of the industrial motor drive systems are equipped with the conventional line-commutated front-end rectifiers, and being one of the main sources of harmonics in the power line. While a parallel combination of these drive units elevates current quality issues, a proper arrangement...... of them can lead to the cancellation of specific harmonics. This paper proposes a new cost-effective harmonic mitigation solution for multi-drive systems using a predictive pulse pattern current modulation control strategy. The proposed technique applies suitable interaction among parallel drive units...

  12. PSB beam longitudinal blow-up by phase modulation with the digital LLRF prototype system

    CERN Document Server

    Angoletta, M E; Butterworth, A; Findlay, A; Jaussi, M; Leinonen, P; Molendijk, J; Sanchez-Quesada, J

    2014-01-01

    The PSB will be upgraded to a new, Digital Low-Level RF (DLLRF) system in 2014 at the injectors’ restart after LS1. This DLLRF is an evolution of that successfully deployed in LEIR and comprises new hardware, software and implementation strategies. Machine development studies have been carried out in the PSB over recent years with the existing LEIR-style hardware installed in PSB ring four. These studies have allowed testing approaches and validating implementation strategies. This note focuses on a series of MDs carried out during the 2011 run where a new implementation of the longitudinal beam blow-up obtained by phase modulation was tested. Test results and effects on the beam are show for a CNGS-type beam. Finally, an overview is given of the final longitudinal blow-up implementation planned with the new hardware, which will be operationally deployed in 2014.

  13. Phase-Modulated Nonresonant Laser Pulses Can Selectively Convert Enantiomers in a Racemic Mixture

    DEFF Research Database (Denmark)

    Thomas, Esben Folger; Henriksen, Niels Engholm

    2017-01-01

    -modulated, nonresonant, linearly polarized Gaussian laser pulses that can selectively deracemize a racemic mixture of 3D-oriented, 3,5-difluoro-3',5'-dibromobiphenyl (F2H3C6-C6H3Br2) molecules, the laser-induced dynamics of which are well studied experimentally. These results strongly suggest that designing a closed......Deracemization occurs when a racemic molecular mixture is transformed into a mixture containing an excess of a single enantiomer. Recent advances in ultrafast laser technology hint at the possibility of using shaped pulses to generate deracemization via selective enantiomeric conversion; however......, experimental implementation remains a challenge and has not yet been achieved. Here we suggest a simple, yet novel approach to laser-induced enantiomeric conversion based on dynamic Stark control. We demonstrate theoretically that current laser and optical technology can be used to generate a pair of phase...

  14. Resolving glass transition in Te-based phase-change materials by modulated differential scanning calorimetry

    Science.gov (United States)

    Chen, Yimin; Mu, Sen; Wang, Guoxiang; Shen, Xiang; Wang, Junqiang; Dai, Shixun; Xu, Tiefeng; Nie, Qiuhua; Wang, Rongping

    2017-10-01

    Glass transitions of Te-based phase-change materials (PCMs) were studied by modulated differential scanning calorimetry. It was found that both Ge2Sb2Te5 and GeTe are marginal glass formers with ΔT (= T x - T g) less than 2.1 °C when the heating rate is below 3 °C min-1. The fragilities of Ge2Sb2Te5 and GeTe can be estimated as 46.0 and 39.7, respectively, around the glass transition temperature, implying that a fragile-to-strong transition would be presented in such Te-based PCMs. The above results provide direct experimental evidence to support the investigation of crystallization kinetics in supercooled liquid PCMs.

  15. Environmental quality modulates the cooperative and competitive nature of a microbial cross-feeding mutualism

    Science.gov (United States)

    Hoek, Tim; Axelrod, Kevin; Yurtsev, Eugene; Gore, Jeff

    Mutualisms are essential for ecosystem function and stability. However, in some environments the competitive aspects of an interaction may dominate the mutualistic aspects. Although these transitions could have far-reaching implications, it has been difficult to study the causes and consequences of this mutualistic-competitive transition in experimentally tractable systems. Here we experimentally study a microbial cross-feeding mutualism in which each yeast strain supplies an essential amino acid for its partner strain. We find that, depending upon the amino acid concentration, this pair of strains can exhibit any of: obligatory mutualism, facultative mutualism, competition, parasitism, competitive exclusion, or failed mutualism leading to extinction of the population. A simple model capturing the essential features of this interaction predicts that environmental quality specifies the outcome and provides a ``phase diagram'' of net interactions in this mutualism. In addition, the model accurately predicts that changes in the dynamics of the mutualism in deteriorating environments can predict that population collapse is imminent. Our results provide a general framework for how mutualisms may transition between qualitatively different regimes of interaction.

  16. Qualification of barrel pixel detector modules for the Phase 1 Upgrade of the CMS vertex detector

    CERN Document Server

    Kudella, Simon

    2016-01-01

    To withstand the higher particle rates of LHC Runs 2 and 3, with expected luminosities of up to $2\\times 10^{34}\\,\\mathrm{cm^{-2}s^{-1}}$, the current CMS pixel detector at the LHC will be replaced as part of the CMS Phase I Upgrade during the extended winter shutdown in 2016/17. The new pixel detector features a new geometry with one additional detector layer in the barrel region~(BPIX) and one pair of additional disks in the forward region~(FPIX), new digital readout chips as well as a new CO$_{2}$-based cooling system for both the barrel and forward region. The BPIX detector module production is summarized, with special focus on the different stages of quality assurance. The quality tests as well as the calibrations which all produced modules undergo in a temperature and humidity controlled environment are described. Exemplarily, the KIT/Aachen production line and its subprocesses are presented together with its quality and yields.

  17. The Possibility of Phase Change Materials (PCM Usage to Increase Efficiency of the Photovoltaic Modules

    Directory of Open Access Journals (Sweden)

    Klugmann-Radziemska Ewa

    2014-01-01

    Full Text Available Solar energy is widely available, free and inexhaustible. Furthermore this source of energy is the most friendly to the environment. For direct conversion of solar energy into useful forms like of electricity and thermal energy, respectively photovoltaic cells and solar collectors are being used. Forecast indicate that the first one solution will soon have a significant part in meeting the global energy demand. Therefore it is highly important to increase their efficiency in the terms of providing better energy conversion conditions. It can be obtain by designing new devices or by modifications of existing ones. This article presents general issues of photovoltaic installations exposed to work in high temperatures and basic concepts about phase change materials (PCMs. The paper presents the possibility of PCM usage to receive heat from the photovoltaic module. Specially designed test stand, consisting of PV module covered with a layer of PCM has been build and tested. Current-voltage characteristics of the cell without PCM material and with a layer of PCM have been presented. Authors also describe the results of the electrical and thermal characteristic of a coupled PV-PCM system.

  18. Pressure distribution over tube surfaces of tube bundle subjected to two phase cross flow

    International Nuclear Information System (INIS)

    Sim, Woo Gun

    2013-01-01

    Two phase vapor liquid flows exist in many shell and tube heat exchangers such as condensers, evaporators and nuclear steam generators. To understand the fluid dynamic forces acting on a structure subjected to a two phase flow, it is essential to obtain detailed information about the characteristics of a two phase flow. The characteristics of a two phase flow and the flow parameters were introduced, and then, an experiment was performed to evaluate the pressure loss in the tube bundles and the fluid dynamic force acting on the cylinder owing to the pressure distribution. A two phase flow was pre mixed at the entrance of the test section, and the experiments were undertaken using a normal triangular array of cylinders subjected to a two phase cross flow. The pressure loss along the flow direction in the tube bundles was measured to calculate the two phase friction multiplier, and the multiplier was compared with the analytical value. Furthermore, the circular distributions of the pressure on the cylinders were measured. Based on the distribution and the fundamental theory of two phase flow, the effects of the void fraction and mass flux per unit area on the pressure coefficient and the drag coefficient were evaluated. The drag coefficient was calculated by integrating the measured pressure coefficient and the drag coefficient were evaluated. The drag coefficient was calculated by integrating the measured pressure on the tube by a numerical method. It was found that for low mass fluxes, the measured two phase friction multipliers agree well with the analytical results, and good agreement for the effect of the void fraction on the drag coefficients, as calculated by the measured pressure distributions, is shown qualitatively, as compared to the existing experimental results

  19. Cross-layer designed adaptive modulation algorithm with packet combining and truncated ARQ over MIMO Nakagami fading channels

    KAUST Repository

    Aniba, Ghassane

    2011-04-01

    This paper presents an optimal adaptive modulation (AM) algorithm designed using a cross-layer approach which combines truncated automatic repeat request (ARQ) protocol and packet combining. Transmissions are performed over multiple-input multiple-output (MIMO) Nakagami fading channels, and retransmitted packets are not necessarily modulated using the same modulation format as in the initial transmission. Compared to traditional approach, cross-layer design based on the coupling across the physical and link layers, has proven to yield better performance in wireless communications. However, there is a lack for the performance analysis and evaluation of such design when the ARQ protocol is used in conjunction with packet combining. Indeed, previous works addressed the link layer performance of AM with truncated ARQ but without packet combining. In addition, previously proposed AM algorithms are not optimal and can provide poor performance when packet combining is implemented. Herein, we first show that the packet loss rate (PLR) resulting from the combining of packets modulated with different constellations can be well approximated by an exponential function. This model is then used in the design of an optimal AM algorithm for systems employing packet combining, truncated ARQ and MIMO antenna configurations, considering transmission over Nakagami fading channels. Numerical results are provided for operation with or without packet combining, and show the enhanced performance and efficiency of the proposed algorithm in comparison with existing ones. © 2011 IEEE.

  20. Experimental observation of chaotic phase synchronization of a periodically pump-modulated multimode microchip Nd:YVO{sub 4} laser

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chien-Hui; Kuo, Chie-Tong [Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan, ROC (China); Hsu, Tzu-Fang, E-mail: tfhsu@mail.npue.edu.tw [Department of Applied Physics, National Pingtung University of Education, Pingtung 900, Taiwan, ROC (China); Jan, Hengtai; Han, Shiang-Yi [Department of Physics, National Kaohsiung Normal University, No. 62, Shenjhong Rd., Yanchao District, Kaohsiung City 824, Taiwan, ROC (China); Ho, Ming-Chung, E-mail: t1603@nknucc.nknu.edu.tw [Department of Physics, National Kaohsiung Normal University, No. 62, Shenjhong Rd., Yanchao District, Kaohsiung City 824, Taiwan, ROC (China); Jiang, I-Min [Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan, ROC (China)

    2012-03-12

    In this Letter we demonstrate the experimental observation of chaotic phase synchronization (CPS) in a periodically pump-modulated multimode microchip Nd:YVO{sub 4} laser. PS transition is displayed via the stroboscopic technique. We apply the recurrence probability and correlation probability of recurrence to estimate the degree of PS. The degree of PS is studied taking into account the modulation amplitude and modulation frequency. We also propose an experimental compatible numerical simulation to reflect the fact that the Arnold tongues are experimentally and numerically exhibited in the periodically pump-modulated multimode microchip Nd:YVO{sub 4} laser. -- Highlights: ► We show chaotic phase synchronization in a pump-modulated microchip Nd:YVO{sub 4} laser. ► Phase synchronization (PS) transition is displayed via the stroboscopic technique. ► The degree of PS is studied taking into account the modulation parameters. ► The Arnold tongues are experimentally and numerically exhibited in the laser.

  1. A DC-Link Modulation Scheme with Phase-Shifted Current Control for Harmonic Cancellations in Multidrive Applications

    DEFF Research Database (Denmark)

    Yang, Yongheng; Davari, Pooya; Zare, Firuz

    2016-01-01

    of a new DC link modulation scheme with a phase-shifted current control enabled by the SCR. The DC-link current modulation scheme is implemented by adding and subtracting specific modulation levels, which makes the total currents drawn from the grid “multi-level”, resulting in an improved current quality......This letter proposes a harmonic mitigation strategy to cancel out current harmonics induced by the front-end rectifiers in multi-drive systems, which consist of diode rectifiers, Silicon-Controlled Rectifiers (SCR), and boost converters in the DC-link. The proposed strategy is a combination...

  2. Broader color gamut of color-modulating optical coating display based on indium tin oxide and phase change materials.

    Science.gov (United States)

    Ni, Zhigang; Mou, Shenghong; Zhou, Tong; Cheng, Zhiyuan

    2018-05-01

    A color-modulating optical coating display based on phase change materials (PCM) and indium tin oxide (ITO) is fabricated and analyzed. We demonstrate that altering the thickness of top-ITO in this PCM-based display device can effectively change color. The significant role of the top-ITO layer in the thin-film interference in this multilayer system is confirmed by experiment as well as simulation. The ternary-color modulation of devices with only 5 nano thin layer of phase change material is achieved. Furthermore, simulation work demonstrates that a stirringly broader color gamut can be obtained by introducing the control of the top-ITO thickness.

  3. Does the placebo effect modulate drug bioavailability? Randomized cross-over studies of three drugs.

    Science.gov (United States)

    Hammami, Muhammad M; Yusuf, Ahmed; Shire, Faduma S; Hussein, Rajaa; Al-Swayeh, Reem

    2017-05-23

    Medication effect is the sum of its drug, placebo, and drug*placebo interaction effects. It is conceivable that the interaction effect involves modulating drug bioavailability; it was previously observed that being aware of caffeine ingestion may prolong caffeine plasma half-life. This study was set to evaluate such concept using different drugs. Balanced single-dose, two-period, two-group, cross-over design was used to compare the pharmacokinetics of oral cephalexin, ibuprofen, and paracetamol, each described by its name (overt) or as placebo (covert). Volunteers and study coordinators were deceived as to study aim. Drug concentrations were determined blindly by in-house, high performance liquid chromatography assays. Terminal-elimination half-life (t ½ ) (primary outcome), maximum concentration (C max ), C max first time (T max ), terminal-elimination-rate constant (λ), area-under-the-concentration-time-curve, to last measured concentration (AUC T ), extrapolated to infinity (AUC I ), or to T max of overt drug (AUC Overttmax ), and C max /AUC I were calculated blindly using standard non-compartmental method. Covert-vs-overt effect on drug pharmacokinetics was evaluated by analysis-of-variance (ANOVA, primary analysis), 90% confidence interval (CI) using the 80.00-125.00% bioequivalence range, and percentage of individual pharmacokinetic covert/overt ratios that are outside the +25% range. Fifty, 30, and 50 healthy volunteers (18%, 10%, and 6% females, mean (SD) age 30.8 (6.2), 31.4 (6.6), and 31.2 (5.4) years) participated in 3 studies on cephalexin, ibuprofen, and paracetamol, respectively. Withdrawal rate was 4%, 0%, and 4%, respectively. Eighteen blood samples were obtained over 6, 10, and 14 h in each study period of the three drugs, respectively. ANOVA showed no significant difference in any pharmacokinetic parameter for any of the drugs. The 90% CIs for AUC T , AUC I , C max , AUC Overttmax , and C max /AUC I were within the bioequivalence range, except

  4. Network statistics of genetically-driven gene co-expression modules in mouse crosses

    Directory of Open Access Journals (Sweden)

    Marie-Pier eScott-Boyer

    2013-12-01

    Full Text Available In biology, networks are used in different contexts as ways to represent relationships between entities, such as for instance interactions between genes, proteins or metabolites. Despite progress in the analysis of such networks and their potential to better understand the collective impact of genes on complex traits, one remaining challenge is to establish the biologic validity of gene co-expression networks and to determine what governs their organization. We used WGCNA to construct and analyze seven gene expression datasets from several tissues of mouse recombinant inbred strains (RIS. For six out of the 7 networks, we found that linkage to module QTLs (mQTLs could be established for 29.3% of gene co-expression modules detected in the several mouse RIS. For about 74.6% of such genetically-linked modules, the mQTL was on the same chromosome as the one contributing most genes to the module, with genes originating from that chromosome showing higher connectivity than other genes in the modules. Such modules (that we considered as genetically-driven had network statistic properties (density, centralization and heterogeneity that set them apart from other modules in the network. Altogether, a sizeable portion of gene co-expression modules detected in mouse RIS panels had genetic determinants as their main organizing principle. In addition to providing a biologic interpretation validation for these modules, these genetic determinants imparted on them particular properties that set them apart from other modules in the network, to the point that they can be predicted to a large extent on the basis of their network statistics.

  5. Spin Forming Aluminum Crew Module (CM) Metallic Aft Pressure Vessel Bulkhead (APVBH) - Phase II

    Science.gov (United States)

    Hoffman, Eric K.; Domack, Marcia S.; Torres, Pablo D.; McGill, Preston B.; Tayon, Wesley A.; Bennett, Jay E.; Murphy, Joseph T.

    2015-01-01

    The principal focus of this project was to assist the Multi-Purpose Crew Vehicle (MPCV) Program in developing a spin forming fabrication process for manufacture of the Orion crew module (CM) aft pressure vessel bulkhead. The spin forming process will enable a single piece aluminum (Al) alloy 2219 aft bulkhead resulting in the elimination of the current multiple piece welded construction, simplify CM fabrication, and lead to an enhanced design. Phase I (NASA TM-2014-218163 (1)) of this assessment explored spin forming the single-piece CM forward pressure vessel bulkhead. The Orion MPCV Program and Lockheed Martin (LM) recently made two critical decisions relative to the NESC Phase I work scope: (1) LM selected the spin forming process to manufacture a single-piece aft bulkhead for the Orion CM, and (2) the aft bulkhead will be manufactured from Al 2219. Based on the Program's new emphasis related to the spin forming process, the NESC was asked to conduct a Phase II assessment to assist in the LM manufacture of the aft bulkhead and to conduct a feasibility study into spin forming the Orion CM cone. This activity was approved on June 19, 2013. Dr. Robert Piascik, NASA Technical Fellow for Materials at the Langley Research Center (LaRC), was selected to lead this assessment. The project plan was approved by the NASA Engineering and Safety Center (NESC) Review Board (NRB) on July 18, 2013. The primary stakeholders for this assessment were the NASA and LM MPCV Program offices. Additional benefactors are commercial launch providers developing CM concepts.

  6. A Comparison of Two Objective Measures of Binaural Processing: The Interaural Phase Modulation Following Response and the Binaural Interaction Component.

    Science.gov (United States)

    Haywood, Nicholas R; Undurraga, Jaime A; Marquardt, Torsten; McAlpine, David

    2015-12-30

    There has been continued interest in clinical objective measures of binaural processing. One commonly proposed measure is the binaural interaction component (BIC), which is obtained typically by recording auditory brainstem responses (ABRs)-the BIC reflects the difference between the binaural ABR and the sum of the monaural ABRs (i.e., binaural - (left + right)). We have recently developed an alternative, direct measure of sensitivity to interaural time differences, namely, a following response to modulations in interaural phase difference (the interaural phase modulation following response; IPM-FR). To obtain this measure, an ongoing diotically amplitude-modulated signal is presented, and the interaural phase difference of the carrier is switched periodically at minima in the modulation cycle. Such periodic modulations to interaural phase difference can evoke a steady state following response. BIC and IPM-FR measurements were compared from 10 normal-hearing subjects using a 16-channel electroencephalographic system. Both ABRs and IPM-FRs were observed most clearly from similar electrode locations-differential recordings taken from electrodes near the ear (e.g., mastoid) in reference to a vertex electrode (Cz). Although all subjects displayed clear ABRs, the BIC was not reliably observed. In contrast, the IPM-FR typically elicited a robust and significant response. In addition, the IPM-FR measure required a considerably shorter recording session. As the IPM-FR magnitude varied with interaural phase difference modulation depth, it could potentially serve as a correlate of perceptual salience. Overall, the IPM-FR appears a more suitable clinical measure than the BIC. © The Author(s) 2015.

  7. Biomolecule-recognition gating membrane using biomolecular cross-linking and polymer phase transition.

    Science.gov (United States)

    Kuroki, Hidenori; Ito, Taichi; Ohashi, Hidenori; Tamaki, Takanori; Yamaguchi, Takeo

    2011-12-15

    We present for the first time a biomolecule-recognition gating system that responds to small signals of biomolecules by the cooperation of biorecognition cross-linking and polymer phase transition in nanosized pores. The biomolecule-recognition gating membrane immobilizes the stimuli-responsive polymer, including the biomolecule-recognition receptor, onto the pore surface of a porous membrane. The pore state (open/closed) of this gating membrane depends on the formation of specific biorecognition cross-linking in the pores: a specific biomolecule having multibinding sites can be recognized by several receptors and acts as the cross-linker of the grafted polymer, whereas a nonspecific molecule cannot. The pore state can be distinguished by a volume phase transition of the grafted polymer. In the present study, the principle of the proposed system is demonstrated using poly(N-isopropylacrylamide) as the stimuli-responsive polymer and avidin-biotin as a multibindable biomolecule-specific receptor. As a result of the selective response to the specific biomolecule, a clear permeability change of an order of magnitude was achieved. The principle is versatile and can be applied to many combinations of multibindable analyte-specific receptors, including antibody-antigen and lectin-sugar analogues. The new gating system can find wide application in the bioanalytical field and aid the design of novel biodevices.

  8. Simulation of Processes in Dual Three-Phase System on the Base of Four Inverters with Synchronized Modulation

    OpenAIRE

    Oleschuk, Valentin; Grandi, Gabriele; Sanjeevikumar, Padmanaban

    2011-01-01

    Novel method of space-vector-based pulse-width modulation (PWM) has been disseminated for synchronous control of four inverters feeding six-phase drive on the base of asymmetrical induction motor which has two sets of windings spatially shifted by 30 electrical degrees. Basic schemes of synchronized PWM, applied for control of four separate voltage-source inverters, allow both continuous phase voltages synchronization in the system and required power sharing between DC sources. Detailed MATLA...

  9. Novel trigger-capable modules for the future CMS tracking detector and inclusive top quark pair production cross section at √(s)=13 TeV

    International Nuclear Information System (INIS)

    Harb, Ali

    2017-07-01

    This work covers two important aspects in the field of high-energy physics; detector development and physics data analysis. The first part of this thesis is devoted to the detector development activities for the Phase-II upgrade of the Compact Muon Solenoid (CMS) experiment's outer tracking detector. To cope with the increased luminosity during the high-luminosity era of the Large Hadron Collider (LHC), it is foreseen to replace the existing tracking system of CMS with an entirely new system. Owing to a novel module concept called the p_T-module, the upgraded tracking system will be able to provide first level trigger information by means of an on-board momentum discrimination logic. This will be achieved using a new readout chip, the so-called CMS Binary Chip (CBC). The very first test beam measurement using p_T-module prototypes, equipped with the CBC chip is presented and discussed. The obtained results serve as a proof-of-concept for such modules and shows that the CBC performs as expected. In the second part of this thesis, the measurement of the top quark pair production cross section is addressed. The measurement is performed using 2.2 fb"-"1 of data collected by the CMS detector at a center-of-mass energy of 13 TeV. Results are shown in the eμ di-lepton channel, and for the first time at such energy, in the ee and μμ channels. With an improved treatment of systematic uncertainties, the results in all three channels are found to be in agreement with the theoretical predictions.

  10. Novel trigger-capable modules for the future CMS tracking detector and inclusive top quark pair production cross section at √(s)=13 TeV

    Energy Technology Data Exchange (ETDEWEB)

    Harb, Ali

    2017-07-15

    This work covers two important aspects in the field of high-energy physics; detector development and physics data analysis. The first part of this thesis is devoted to the detector development activities for the Phase-II upgrade of the Compact Muon Solenoid (CMS) experiment's outer tracking detector. To cope with the increased luminosity during the high-luminosity era of the Large Hadron Collider (LHC), it is foreseen to replace the existing tracking system of CMS with an entirely new system. Owing to a novel module concept called the p{sub T}-module, the upgraded tracking system will be able to provide first level trigger information by means of an on-board momentum discrimination logic. This will be achieved using a new readout chip, the so-called CMS Binary Chip (CBC). The very first test beam measurement using p{sub T}-module prototypes, equipped with the CBC chip is presented and discussed. The obtained results serve as a proof-of-concept for such modules and shows that the CBC performs as expected. In the second part of this thesis, the measurement of the top quark pair production cross section is addressed. The measurement is performed using 2.2 fb{sup -1} of data collected by the CMS detector at a center-of-mass energy of 13 TeV. Results are shown in the eμ di-lepton channel, and for the first time at such energy, in the ee and μμ channels. With an improved treatment of systematic uncertainties, the results in all three channels are found to be in agreement with the theoretical predictions.

  11. Analysis and Minimization of Output Current Ripple for Discontinuous Pulse-Width Modulation Techniques in Three-Phase Inverters

    Directory of Open Access Journals (Sweden)

    Gabriele Grandi

    2016-05-01

    Full Text Available This paper gives the complete analysis of the output current ripple in three-phase voltage source inverters considering the different discontinuous pulse-width modulation (DPWM strategies. In particular, peak-to-peak current ripple amplitude is analytically evaluated over the fundamental period and compared among the most used DPWMs, including positive and negative clamped (DPWM+ and DPWM−, and the four possible combinations between them, usually named as DPWM0, DPWM1, DPWM2, and DPWM3. The maximum and the average values of peak-to-peak current ripple are estimated, and a simple method to correlate the ripple envelope with the ripple rms is proposed and verified. Furthermore, all the results obtained by DPWMs are compared to the centered pulse-width modulation (CPWM, equivalent to the space vector modulation to identify the optimal pulse-width modulation (PWM strategy as a function of the modulation index, taking into account the different average switching frequency. In this way, the PWM technique providing for the minimum output current ripple is identified over the whole modulation range. The analytical developments and the main results are experimentally verified by current ripple measurements with a three-phase PWM inverter prototype supplying an induction motor load.

  12. Pulse-width modulation for small heat pump installations - Phase 4; Pulsbreitenmodulation fuer Kleinwaermepumpenanlagen. Phase 4: Erweiterung der PBM-Regler fuer Kombianlagen

    Energy Technology Data Exchange (ETDEWEB)

    Bianchi, M.; Shafai, E. [Eidgenoessische Technische Hochschule (ETH), Institut fuer Mess- und Regeltechnik, Zuerich (Switzerland); Gabathuler, H.R.; Mayer, H. [Gabathuler AG, Beratende Ingenieure, Diessenhofen (Switzerland)

    2005-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) presents the results of the fourth phase of a project that investigated three types of pulse-width modulation (PWM) controllers that were developed during its first two phases. A third phase monitored the controllers when used in a simulated environment and for a real-life heat pump. The report discusses the fourth phase of the project, in which the controller was further developed and tested using the building emulation developed in the third phase. The functioning of the self-regulating controller and its use of meteorological data is described and the savings to be made in heating costs are discussed.

  13. Identifying the 'right' supplier for module developments-a cross-industrial case analysis

    NARCIS (Netherlands)

    Eggers, Justus Erich; Hofman, Erwin; Schiele, Holger; Holschbach, Elmar

    2017-01-01

    Relational view argues that buying companies should integrate supplier resources in new product development (NPD) projects to realise competitive advantages. Due to decoupling of modules and the associated opportunity to allocate development activities to upstream suppliers, modular product

  14. Behold the voice of wrath: Cross-modal modulation of visual attention by anger prosody

    OpenAIRE

    Brosch, Tobias; Grandjean, Didier Maurice; Sander, David; Scherer, Klaus R.

    2008-01-01

    Emotionally relevant stimuli are prioritized in human information processing. It has repeatedly been shown that selective spatial attention is modulated by the emotional content of a stimulus. Until now, studies investigating this phenomenon have only examined withinmodality effects, most frequently using pictures of emotional stimuli to modulate visual attention. In this study, we used simultaneously presented utterances with emotional and neutral prosody as cues for a visually presented tar...

  15. Laterally structured ripple and square phases with one and two dimensional thickness modulations in a model bilayer system.

    Science.gov (United States)

    Debnath, Ananya; Thakkar, Foram M; Maiti, Prabal K; Kumaran, V; Ayappa, K G

    2014-10-14

    Molecular dynamics simulations of bilayers in a surfactant/co-surfactant/water system with explicit solvent molecules show formation of topologically distinct gel phases depending upon the bilayer composition. At low temperatures, the bilayers transform from the tilted gel phase, Lβ', to the one dimensional (1D) rippled, Pβ' phase as the surfactant concentration is increased. More interestingly, we observe a two dimensional (2D) square phase at higher surfactant concentration which, upon heating, transforms to the gel Lβ' phase. The thickness modulations in the 1D rippled and square phases are asymmetric in two surfactant leaflets and the bilayer thickness varies by a factor of ∼2 between maximum and minimum. The 1D ripple consists of a thinner interdigitated region of smaller extent alternating with a thicker non-interdigitated region. The 2D ripple phase is made up of two superimposed square lattices of maximum and minimum thicknesses with molecules of high tilt forming a square lattice translated from the lattice formed with the thickness minima. Using Voronoi diagrams we analyze the intricate interplay between the area-per-head-group, height modulations and chain tilt for the different ripple symmetries. Our simulations indicate that composition plays an important role in controlling the formation of low temperature gel phase symmetries and rippling accommodates the increased area-per-head-group of the surfactant molecules.

  16. Suppression of Brillouin scattering in fibre-optical parametric amplifier by applying temperature control and phase modulation

    DEFF Research Database (Denmark)

    Lorenzen, Michael Rodas; Noordegraaf, Danny; Nielsen, Carsten Vandel

    2009-01-01

    An increased gain in a fibre-optical parametric amplifier through suppression of stimulated Brillouin scattering is demonstrated by applying a temperature distribution along the fibre for a fixed phase modulation of the pump. The temperature distribution slightly impacts the gain spectrum....

  17. Control strategy for Single-phase Transformerless Three-leg Unified Power Quality Conditioner Based on Space Vector Modulation

    DEFF Research Database (Denmark)

    Lu, Yong; Xiao, Guochun; Wang, Xiongfei

    2016-01-01

    The unified power quality conditioner (UPQC) is known as an effective compensation device to improve PQ for sensitive end-users. This paper investigates the operation and control of a single-phase three-leg UPQC (TL-UPQC), where a novel space vector modulation method is proposed for naturally...

  18. Nonorthogonal multiple access and carrierless amplitude phase modulation for flexible multiuser provisioning in 5G mobile networks

    NARCIS (Netherlands)

    Altabas, J.A.; Rommel, S.; Puerta, R.; Izquierdo, D.; Ignacio Garces, J.; Antonio Lazaro, J.; Vegas Olmos, J.J.; Tafur Monroy, I.

    2017-01-01

    In this paper, a combined nonorthogonal multiple access (NOMA) and multiband carrierless amplitude phase modulation (multiCAP) scheme is proposed for capacity enhancement of and flexible resource provisioning in 5G mobile networks. The proposed scheme is experimentally evaluated over a W-band

  19. Protection Of TEG Module at High Temperature Transient Boundary Condition Using Phase Change Materials, an Experimental Investigation

    DEFF Research Database (Denmark)

    Ahmadi Atouei,, Saeed; Rezaniakolaei, Alireza; Akbar Ranjbar, Ali

    2017-01-01

    phase change materials (PCM) in an aluminium box are placed between heat source and the thermoelectric module. The results show when the input heat flux is high, a fraction of the thermal energy is saved in the PCM during the melting process, and when the heat source is off, the saved energy in the PCM...

  20. Self-phase modulation of a single-cycle terahertz pulse by nonlinear free-carrier response in a semiconductor

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hvam, Jørn Märcher; Hoffmann, Matthias C.

    2012-01-01

    We investigate the self-phase modulation (SPM) of a single-cycle terahertz pulse in a semiconductor, using bulk n-GaAs as a model system. The SPM arises from the heating of free electrons in the electric field of the terahertz pulse, leading to an ultrafast reduction of the plasma frequency...

  1. Unravelling the role of quantum interference in the weak-field laser phase modulation control of photofragment distributions

    DEFF Research Database (Denmark)

    García-Vela, Alberto; Henriksen, Niels Engholm

    2016-01-01

    The role played by quantum interference in the laser phase modulation coherent control of photofragment distributions in the weak-field regime is investigated in detail in this work. The specific application involves realistic wave packet calculations of the transient vibrational populations of t...

  2. On the phase velocity of plasma waves in a self-modulated laser wake-field accelerator

    NARCIS (Netherlands)

    Andreev, N. E.; Kirsanov, V. I.; Sakharov, A. S.; van Amersfoort, P. W.; Goloviznin, V. V.

    1996-01-01

    The properties of the wake field excited by a flattop laser pulse with a sharp leading edge and a power below the critical one for relativistic self-focusing are studied analytically and numerically with emphasis on the phase velocity of the plasma wave. The paraxial model describing modulation of

  3. Contrast enhancement in an optical time-domain reflectometer via self-phase modulation compensation by chirped probe pulses

    International Nuclear Information System (INIS)

    Alekseev, A E; Potapov, V T; Vdovenko, V S; Simikin, D E; Gorshkov, B G

    2016-01-01

    In the present paper we propose a novel method for optical time-domain reflectometer (OTDR)–reflectogram contrast enhancement via compensation of nonlinear distortions of propagating probe pulse, which arise due to the self-phase modulation (SPM) effect in optical fiber. The compensation is performed via preliminary frequency modulation (chirp) of the initial probe pulse according to the specific law. As a result the OTDR contrast at some distant predefined fiber point is fully restored to the value of non-distorted probe pulse at the beginning of the fiber line. As a result, the performance of the phase OTDR increases. The point of full SPM compensation could be shifted to any other point of the fiber line via preliminary frequency modulation index change. The feasibility of the proposed method is theoretically proved and experimentally demonstrated. (paper)

  4. Switching Loss Reduction in the Three-Phase Quasi-Z-Source Inverters Utilizing Modified Space Vector Modulation Strategies

    DEFF Research Database (Denmark)

    Abdelhakim, Ahmed; Davari, Pooya; Blaabjerg, Frede

    2018-01-01

    Several single-stage topologies have been introduced since kicking off the three-phase Z-source inverter (ZSI), and among these topologies, the quasi-ZSI (qZSI) is the most common one due to its simple structure and continuous input current. Furthermore, different modulation strategies, utilizing...... multiple reference signals, have been developed as well. However, prior art modulation methods have some demerits, such as the complexity of generating the gate signals, the increased number of switch commutations with continuous commutation at high current level during the entire fundamental cycle...... the generation of the gate signals by utilizing only three reference signals, and achieving a single switch commutation at a time. These modulation strategies are analyzed and compared to the conventional ones, where a reduced-scale 1 kVA three-phase qZSI is designed and simulated using these different...

  5. Space Vector Pulse Width Modulation Strategy for Single-Phase Three-Level CIC T-source Inverter

    DEFF Research Database (Denmark)

    Shults, Tatiana E.; Husev, Oleksandr O.; Blaabjerg, Frede

    2016-01-01

    This paper presents a novel space vector pulse-width modulation strategy for a single-phase three-level buck-boost inverter based on an impedance-source network. The case study system is based on T-source inverter with continuous input current. To demonstrate the improved performance of the inver......This paper presents a novel space vector pulse-width modulation strategy for a single-phase three-level buck-boost inverter based on an impedance-source network. The case study system is based on T-source inverter with continuous input current. To demonstrate the improved performance...... of the inverter, the strategy was compared the traditional pulse-width modulation. It is shown that the approach proposed has fewer switching states and does not suffer from neutral point misbalance....

  6. Cascade photonic integrated circuit architecture for electro-optic in-phase quadrature/single sideband modulation or frequency conversion.

    Science.gov (United States)

    Hasan, Mehedi; Hall, Trevor

    2015-11-01

    A photonic integrated circuit architecture for implementing frequency upconversion is proposed. The circuit consists of a 1×2 splitter and 2×1 combiner interconnected by two stages of differentially driven phase modulators having 2×2 multimode interference coupler between the stages. A transfer matrix approach is used to model the operation of the architecture. The predictions of the model are validated by simulations performed using an industry standard software tool. The intrinsic conversion efficiency of the proposed design is improved by 6 dB over the alternative functionally equivalent circuit based on dual parallel Mach-Zehnder modulators known in the prior art. A two-tone analysis is presented to study the linearity of the proposed circuit, and a comparison is provided over the alternative. The proposed circuit is suitable for integration in any platform that offers linear electro-optic phase modulation such as LiNbO(3), silicon, III-V, or hybrid technology.

  7. Electrical system for pulse-width modulated control of a power inverter using phase-shifted carrier signals and related operating methods

    Science.gov (United States)

    Welchko, Brian A [Torrance, CA

    2012-02-14

    Systems and methods are provided for pulse-width modulated control of power inverter using phase-shifted carrier signals. An electrical system comprises an energy source and a motor. The motor has a first set of windings and a second set of windings, which are electrically isolated from each other. An inverter module is coupled between the energy source and the motor and comprises a first set of phase legs coupled to the first set of windings and a second set of phase legs coupled to the second set of windings. A controller is coupled to the inverter module and is configured to achieve a desired power flow between the energy source and the motor by modulating the first set of phase legs using a first carrier signal and modulating the second set of phase legs using a second carrier signal. The second carrier signal is phase-shifted relative to the first carrier signal.

  8. Absorption-Modulated Crossed-Optical Fiber-Sensor Platform for Measurements in Liquid Environments and Flow Streams

    Directory of Open Access Journals (Sweden)

    Paul E. Henning

    2017-01-01

    Full Text Available A new evanescent-wave fiber sensor is described that utilizes absorption-modulated luminescence (AML in combination with a crossed-fiber sensor platform. The luminescence signals of two crossed-fiber reference regions, placed on opposite sides of the stretch of fiber supporting the absorbance sensor, monitor the optical intensity in the fiber core. Evanescent absorption of the sensor reduces a portion of the excitation light and modulates the luminescence of the second reference region. The attenuation is determined from the luminescence intensity of both reference regions similar to the Beer-Lambert Law. The AML-Crossed-Fiber technique was demonstrated using the absorbance of the Zn(II-PAN2 complex at 555 nm. A linear response was obtained over a zinc(II concentration range of 0 to 20 μM (approximately 0 to 1.3 ppm. A nonlinear response was observed at higher zinc(II concentrations and was attributed to depletion of higher-order modes in the fiber. This was corroborated by the measured induced repopulation of these modes.

  9. Rad-hard Location and Attitude Module (R-LAM), Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — R-LAM (Rad-hard Location and Attitude Module), promises a new generation of both integrated navigation modules and stand-alone navigation subsystems including...

  10. Numerical modeling of optical coherent transient processes with complex configurations - II. Angled beams with arbitrary phase modulations

    International Nuclear Information System (INIS)

    Chang Tiejun; Tian Mingzhen; Barber, Zeb W.; Randall Babbitt, Wm.

    2004-01-01

    This work is a continuation of the development of the theoretical model for optical coherent transient (OCT) processes with complex configurations. A theoretical model for angled beams with arbitrary phase modulation has been developed based on the model presented in our previous work for the angled beam geometry. A numerical tool has been devised to simulate the OCT processes involving angled beams with the frequency detuning, chirped, and phase-modulated laser pulses. The simulations for pulse shaping and arbitrary waveform generation (AWG) using OCT processes have been performed. The theoretical analysis of programming and probe schemes for pulse shaper and AWG is also presented including the discussions on the rephasing condition and the phase compensation. The results from the analysis, the simulation, and the experiment show very good agreement

  11. Self-phase modulation enabled, wavelength-tunable ultrafast fiber laser sources: an energy scalable approach.

    Science.gov (United States)

    Liu, Wei; Li, Chen; Zhang, Zhigang; Kärtner, Franz X; Chang, Guoqing

    2016-07-11

    We propose and demonstrate a new approach to implement a wavelength-tunable ultrafast fiber laser source suitable for multiphoton microscopy. We employ fiber-optic nonlinearities to broaden a narrowband optical spectrum generated by an Yb-fiber laser system and then use optical bandpass filters to select the leftmost or rightmost spectral lobes from the broadened spectrum. Detailed numerical modeling shows that self-phase modulation dominates the spectral broadening, self-steepening tends to blue shift the broadened spectrum, and stimulated Raman scattering is minimal. We also find that optical wave breaking caused by fiber dispersion slows down the shift of the leftmost/rightmost spectral lobes and therefore limits the wavelength tuning range of the filtered spectra. We show both numerically and experimentally that shortening the fiber used for spectral broadening while increasing the input pulse energy can overcome this dispersion-induced limitation; as a result, the filtered spectral lobes have higher power, constituting a powerful and practical approach for energy scaling the resulting femtosecond sources. We use two commercially available photonic crystal fibers to verify the simulation results. More specific, use of 20-mm fiber NL-1050-ZERO-2 enables us to implement an Yb-fiber laser based ultrafast source, delivering femtosecond (70-120 fs) pulses tunable from 825 nm to 1210 nm with >1 nJ pulse energy.

  12. Integrated InP frequency discriminator for Phase-modulated microwave photonic links.

    Science.gov (United States)

    Fandiño, J S; Doménech, J D; Muñoz, P; Capmany, J

    2013-02-11

    We report the design, fabrication and characterization of an integrated frequency discriminator on InP technology for microwave photonic phase modulated links. The optical chip is, to the best of our knowledge, the first reported in an active platform and the first to include the optical detectors. The discriminator, designed as a linear filter in intensity, features preliminary SFDR values the range between 67 and 79 dB.Hz(2/3) for signal frequencies in the range of 5-9 GHz limited, in principle, by the high value of the optical losses arising from the use of several free space coupling devices in our experimental setup. As discussed, these losses can be readily reduced by the use of integrated spot-size converters improving the SFDR by 17.3 dB (84-96 dB.Hz(2/3)). Further increase up to a range of (104-116 dB.Hz(2/3)) is possible by reducing the system noise eliminating the EDFA employed in the setup and using a commercially available laser source providing higher output power and lower relative intensity noise. Other paths for improvement requiring a filter redesign to be linear in the optical field are also discussed.

  13. The EORTC module for quality of life in patients with thyroid cancer: phase III.

    Science.gov (United States)

    Singer, Susanne; Jordan, Susan; Locati, Laura D; Pinto, Monica; Tomaszewska, Iwona M; Araújo, Cláudia; Hammerlid, Eva; Vidhubala, E; Husson, Olga; Kiyota, Naomi; Brannan, Christine; Salem, Dina; Gamper, Eva M; Arraras, Juan Ignacio; Ioannidis, Georgios; Andry, Guy; Inhestern, Johanna; Grégoire, Vincent; Licitra, Lisa

    2017-04-01

    The purpose of the study was to pilot-test a questionnaire measuring health-related quality of life (QoL) in thyroid cancer patients to be used with the European Organisation for Research and Treatment of Cancer (EORTC) core questionnaire EORTC QLQ-C30. A provisional questionnaire with 47 items was administered to patients treated for thyroid cancer within the last 2 years. Patients were interviewed about time and help needed to complete the questionnaire, and whether they found the items understandable, confusing or annoying. Items were kept in the questionnaire if they fulfilled pre-defined criteria: relevant to the patients, easy to understand, not confusing, few missing values, neither floor nor ceiling effects, and high variance. A total of 182 thyroid cancer patients in 15 countries participated ( n  = 115 with papillary, n  = 31 with follicular, n  = 22 with medullary, n  = 6 with anaplastic, and n  = 8 with other types of thyroid cancer). Sixty-six percent of the patients needed 15 min or less to complete the questionnaire. Of the 47 items, 31 fulfilled the predefined criteria and were kept unchanged, 14 were removed, and 2 were changed. Shoulder dysfunction was mentioned by 5 patients as missing and an item covering this issue was added. To conclude, the EORTC quality of life module for thyroid cancer (EORTC QLQ-THY34) is ready for the final validation phase IV. © 2017 Society for Endocrinology.

  14. Isotonic force modulates force redevelopment rate of intact frog muscle fibres: evidence for cross-bridge induced thin filament activation

    Science.gov (United States)

    Vandenboom, Rene; Hannon, James D; Sieck, Gary C

    2002-01-01

    We tested the hypothesis that force-velocity history modulates thin filament activation, as assessed by the rate of force redevelopment after shortening (+dF/dtR). The influence of isotonic force on +dF/dtR was assessed by imposing uniform amplitude (2.55 to 2.15 μm sarcomere−1) but different speed releases to intact frog muscle fibres during fused tetani. Each release consisted of a contiguous ramp- and step-change in length. Ramp speed was changed from release to release to vary fibre shortening speed from 1.00 (2.76 ± 0.11 μm half-sarcomere−1 s−1) to 0.30 of maximum unloaded shortening velocity (Vu), thereby modulating isotonic force from 0 to 0.34 Fo, respectively. The step zeroed force and allowed the fibre to shorten unloaded for a brief period of time prior to force redevelopment. Although peak force redevelopment after different releases was similar, +dF/dtR increased by 81 ± 6% (P < 0.05) as fibre shortening speed was reduced from 1.00 Vu. The +dF/dtR after different releases was strongly correlated with the preceding isotonic force (r = 0.99, P < 0.001). Results from additional experiments showed that the slope of slack test plots produced by systematically increasing the step size that followed each ramp were similar. Thus, isotonic force did not influence Vu (mean: 2.84 ± 0.10 μm half-sarcomere−1 s−1, P < 0.05). We conclude that isotonic force modulates +dF/dtR independent of change in Vu, an outcome consistent with a cooperative influence of attached cross-bridges on thin filament activation that increases cross-bridge attachment rate without alteration to cross-bridge detachment rate. PMID:12205189

  15. Micelle size modulation and phase behavior in MEGA-10/Triton X-100 mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Naous, M., E-mail: elzahraadz@yahoo.fr; Molina-Bolívar, J.A.; Ruiz, C. Carnero, E-mail: ccarnero@uma.es

    2014-12-20

    Highlights: • The size of micelles was studied as a function of the micellar composition, NaCl addition and temperature. • Cloud point can be modulated by changing both micellar composition and NaCl addition. • The energetic quantities at the cloud point were evaluated and discussed. - Abstract: This paper reports the effect of temperature and NaCl addition on micelle size and phase behavior in mixtures of N-decanoyl-N-methylglucamide (MEGA-10) and p-tert-octyl-phenoxy polyethylene (9.5) ether (Triton X-100 or TX100). The size of mixed micelles, as determined by dynamic light scattering (DLS), was found to increase with temperature but to be less pronounced at higher proportions of MEGA-10 in the solution. The cloud point was found to increase with an initial increase in the percentage of sugar-based surfactant in the mixture. This phase separation was sensitive to the presence of NaCl in the micellar solution, which induced a cloud point depression, thereby suggesting that the presence of electrolyte produces a marked alteration of the hydration layer of micelles. A thermodynamic analysis was performed assuming the clouding phenomenon to be a liquid–liquid phase-separation process. The resulting ΔG{sub CP}{sup 0} values were positive for all solutions. The cloud point process was exothermic in nature for the mixed micellar system, as proven by the negative value of ΔH{sub CP}{sup 0}. The process was more exothermic as the proportion of sugar-based surfactant in the mixed micelle increased (with and without NaCl in the solution). Furthermore, the negative values of ΔS{sub CP}{sup 0} indicate that the association of micelles in the clouding phenomenon is entropically unfavorable. It was observed from the enthalpy–temperature plots that the change in heat capacity is negative, thus indicating the important role played by dehydration in this thermodynamic process. This study found that the enthalpy–entropy compensation relationship holds for this

  16. Theoretical investigation of the energy performance of a novel MPCM (Microencapsulated Phase Change Material) slurry based PV/T module

    International Nuclear Information System (INIS)

    Qiu, Zhongzhu; Zhao, Xudong; Li, Peng; Zhang, Xingxing; Ali, Samira; Tan, Junyi

    2015-01-01

    Aim of the paper is to present a theoretical investigation into the energy performance of a novel PV/T module that employs the MPCM (Micro-encapsulated Phase Change Material) slurry as the working fluid. This involved (1) development of a dedicated mathematical model and computer program; (2) validation of the model by using the published data; (3) prediction of the energy performance of the MPCM (Microencapsulated Phase Change Material) slurry based PV/T module; and (4) investigation of the impacts of the slurry flow state, concentration ratio, Reynolds number and slurry serpentine size onto the energy performance of the PV/T module. It was found that the established model, based on the Hottel–Whillier assumption, is able to predict the energy performance of the MPCM slurry based PV/T system at a very good accuracy, with 0.3–0.4% difference compared to a validated model. Analyses of the simulation results indicated that laminar flow is not a favorite flow state in terms of the energy efficiency of the PV/T module. Instead, turbulent flow is a desired flow state that has potential to enhance the energy performance of PV/T module. Under the turbulent flow condition, increasing the slurry concentration ratio led to the reduced PV cells' temperature and increased thermal, electrical and overall efficiency of the PV/T module, as well as increased flow resistance. As a result, the net efficiency of the PV/T module reached the peak level at the concentration ratio of 5% at a specified Reynolds number of 3,350. Remaining all other parameters fixed, increasing the diameter of the serpentine piping led to the increased slurry mass flow rate, decreased PV cells' temperature and consequently, increased thermal, electrical, overall and net efficiencies of the PV/T module. In overall, the MPCM slurry based PV/T module is a new, highly efficient solar thermal and power configuration, which has potential to help reduce fossil fuel consumption and carbon emission to

  17. Behold the Voice of Wrath: Cross-Modal Modulation of Visual Attention by Anger Prosody

    Science.gov (United States)

    Brosch, Tobias; Grandjean, Didier; Sander, David; Scherer, Klaus R.

    2008-01-01

    Emotionally relevant stimuli are prioritized in human information processing. It has repeatedly been shown that selective spatial attention is modulated by the emotional content of a stimulus. Until now, studies investigating this phenomenon have only examined "within-modality" effects, most frequently using pictures of emotional stimuli to…

  18. Degradation of gas-phase trichloroethylene over thin-film TiO2 photocatalyst in multi-modules reactor

    International Nuclear Information System (INIS)

    Kim, Sang Bum; Lee, Jun Yub; Kim, Gyung Soo; Hong, Sung Chang

    2009-01-01

    The present paper examined the photocatalytic degradation (PCD) of gas-phase trichloroethylene (TCE) over thin-film TiO 2 . A large-scale treatment of TCE was carried out using scale-up continuous flow photo-reactor in which nine reactors were arranged in parallel and series. The parallel or serial arrangement is a significant factor to determine the special arrangement of whole reactor module as well as to compact the multi-modules in a continuous flow reactor. The conversion of TCE according to the space time was nearly same for parallel and serial connection of the reactors.

  19. Optical UWB pulse generator using an N tap microwave photonic filter and phase inversion adaptable to different pulse modulation formats.

    Science.gov (United States)

    Bolea, Mario; Mora, José; Ortega, Beatriz; Capmany, José

    2009-03-30

    We propose theoretically and demonstrate experimentally an optical architecture for flexible Ultra-Wideband pulse generation. It is based on an N-tap reconfigurable microwave photonic filter fed by a laser array by using phase inversion in a Mach-Zehnder modulator. Since a large number of positive and negative coefficients can be easily implemented, UWB pulses fitted to the FCC mask requirements can be generated. As an example, a four tap pulse generator is experimentally demonstrated which complies with the FCC regulation. The proposed pulse generator allows different pulse modulation formats since the amplitude, polarity and time delay of generated pulse is controlled.

  20. Remarks on nonlinear relation among phases and frequencies in modulational instabilities of parallel propagating Alfvén waves

    Directory of Open Access Journals (Sweden)

    Y. Nariyuki

    2006-01-01

    Full Text Available Nonlinear relations among frequencies and phases in modulational instability of circularly polarized Alfvén waves are discussed, within the context of one dimensional, dissipation-less, unforced fluid system. We show that generation of phase coherence is a natural consequence of the modulational instability of Alfvén waves. Furthermore, we quantitatively evaluate intensity of wave-wave interaction by using bi-coherence, and also by computing energy flow among wave modes, and demonstrate that the energy flow is directly related to the phase coherence generation. We first discuss the modulational instability within the derivative nonlinear Schrödinger (DNLS equation, which is a subset of the Hall-MHD system including the right- and left-hand polarized, nearly degenerate quasi-parallel Alfvén waves. The dominant nonlinear process within this model is the four wave interaction, in which a quartet of waves in resonance can exchange energy. By numerically time integrating the DNLS equation with periodic boundary conditions, and by evaluating relative phase among the quartet of waves, we show that the phase coherence is generated when the waves exchange energy among the quartet of waves. As a result, coherent structures (solitons appear in the real space, while in the phase space of the wave frequency and the wave number, the wave power is seen to be distributed around a straight line. The slope of the line corresponds to the propagation speed of the coherent structures. Numerical time integration of the Hall-MHD system with periodic boundary conditions reveals that, wave power of transverse modes and that of longitudinal modes are aligned with a single straight line in the dispersion relation phase space, suggesting that efficient exchange of energy among transverse and longitudinal wave modes is realized in the Hall-MHD. Generation of the longitudinal wave modes violates the assumptions employed in deriving the DNLS such as the quasi

  1. Compensation for the phase-type spatial periodic modulation of the near-field beam at 1053 nm

    Science.gov (United States)

    Gao, Yaru; Liu, Dean; Yang, Aihua; Tang, Ruyu; Zhu, Jianqiang

    2017-10-01

    A phase-only spatial light modulator is used to provide and compensate for the spatial periodic modulation (SPM) of the near-field beam at the near infrared at 1053nm wavelength with an improved iterative weight-based method. The transmission characteristics of the incident beam has been changed by a spatial light modulator (SLM) to shape the spatial intensity of the output beam. The propagation and reverse propagation of the light in free space are two important processes in the iterative process. The based theory is the beam angular spectrum transmit formula (ASTF) and the principle of the iterative weight-based method. We have made two improvements to the originally proposed iterative weight-based method. We select the appropriate parameter by choosing the minimum value of the output beam contrast degree and use the MATLAB built-in angle function to acquire the corresponding phase of the light wave function. The required phase that compensates for the intensity distribution of the incident SPM beam is iterated by this algorithm, which can decrease the magnitude of the SPM of the intensity on the observation plane. The experimental results show that the phase-type SPM of the near-field beam is subject to a certain restriction. We have also analyzed some factors that make the results imperfect. The experiment results verifies the possible applicability of this iterative weight-based method to compensate for the SPM of the near-field beam.

  2. Refractive index modulation of Sb{sub 70}Te{sub 30} phase-change thin films by multiple femtosecond laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Lei, Kai; Wang, Yang, E-mail: ywang@siom.ac.cn; Jiang, Minghui; Wu, Yiqun [Key Laboratory of High Power Laser Materials, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China)

    2016-05-07

    In this study, the controllable effective refractive index modulation of Sb{sub 70}Te{sub 30} phase-change thin films between amorphous and crystalline states was achieved experimentally by multiple femtosecond laser pulses. The modulation mechanism was analyzed comprehensively by a spectral ellipsometer measurement, surface morphology observation, and two-temperature model calculations. We numerically demonstrate the application of the optically modulated refractive index of the phase-change thin films in a precisely adjustable color display. These results may provide further insights into ultrafast phase-transition mechanics and are useful in the design of programmable photonic and opto-electrical devices based on phase-change memory materials.

  3. Analysis of two-phase flow velocity measurements by cross-correlation techniques and the applicability of the drift flux model for their interpretation

    International Nuclear Information System (INIS)

    Analytis, G.Th.; Luebbesmeyer, D.

    1982-11-01

    An extensive and detailed investigation of two-phase flow velocity measurements by cross-correlating noise signals of information carriers (neutrons, gammas, visible light) modulated by the two-phase flow and registered by two axially placed detectors outside the flow is pursued. To this end, a detailed analysis of velocity measurements in experimental loops and a large number of velocity measurements in a commercial BWR is undertaken, and the applicability and limitations of the drift flux model for their interpretation is investigated. On the basis of this extensive analysis, the authors propose a physically plausible explanation for the deviations in the upper part of the core, expound on why the drift flux model is, to a great extent, not suitable for interpreting two-phase flow velocity measurements by cross-correlation techniques reported in the present work, and conclude that due to the large number of uncertainties and the lack of detailed knowledge about the kind of microstructures of the flow which the detectors prefer to ''sample'', one can safely assume that at least in the lower half of the core the velocity measured can be well approximated by the velocity of the centre of volume, from which the mass fluxes can readily be computed. (Auth.)

  4. ANALYSIS OF PROCESSES IN AN INDEPENDENT GENERATOR WITH A NONCONTACT CASCADE THREE-PHASE MODULATED EXCITER VIA A STAR-CONNECTED CIRCUIT WITH A COMMON MODULATOR PHASE CONNECTION UNDER OPERATION TO AN INDUCTION MOTORS SITE

    Directory of Open Access Journals (Sweden)

    K.M. Vasyliv

    2013-04-01

    Full Text Available By means of a mathematical experiment, electromagnetic and electromechanical processes in an independent electric power supply system based on an asynchronized generator with a three-phase modulated exciter are investigated. The processes are analyzed to specify the working capacity of the power supply system during its operation to an induction motors site. Regularities of the electromagnetic and electromechanical processes behavior versus load intensity and the switch control system parameters are identified.

  5. Road crossing behavior under traffic light conflict: Modulating effects of green light duration and signal congruency.

    Science.gov (United States)

    Lange, Florian; Haiduk, Michael; Boos, Moritz; Tinschert, Peter; Schwarze, Anke; Eggert, Frank

    2016-10-01

    A large number of pedestrians and cyclists regularly ignore the traffic lights to cross the road illegally. In a recent analysis, illegal road crossing behavior has been shown to be enhanced in the presence of incongruent stimulus configurations. Pedestrians and cyclists are more likely to cross against a red light when exposed to an irrelevant conflicting green light. Here, we present experimental and observational data on the factors moderating the risk associated with incongruent traffic lights. In an observational study, we demonstrated that the conflict-related increase in illegal crossing rates is reduced when pedestrian and cyclist green light periods are long. In a laboratory experiment, we manipulated the color of the irrelevant signals to expose participants to different degrees of incongruency. Results revealed that individuals' performance gradually varied as a function of incongruency, suggesting that the negative impact of a conflicting green light can be reduced by slightly adjusting its color. Our findings highlight that the observation of real-world behavior at intersections and the experimental analysis of psychological processes under controlled laboratory conditions can complement each other in identifying risk factors of risky road crossing behavior. Based on this combination, our study elaborates on promising measures to improve safety at signalized intersections. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Broadband photonic single sideband frequency up-converter based on the cross polarization modulation effect in a semiconductor optical amplifier for radio-over-fiber systems.

    Science.gov (United States)

    Lee, Seung-Hun; Kim, Hyoung-Jun; Song, Jong-In

    2014-01-13

    A broadband photonic single sideband (SSB) frequency up-converter based on the cross polarization modulation (XPolM) effect in a semiconductor optical amplifier (SOA) is proposed and experimentally demonstrated. An optical radio frequency (RF) signal in the form of an optical single sideband (OSSB) is generated by the photonic SSB frequency up-converter to solve the power fading problem caused by fiber chromatic dispersion. The generated OSSB RF signal has almost identical optical carrier power and optical sideband power. This SSB frequency up-conversion scheme shows an almost flat electrical RF power response as a function of the RF frequency in a range from 31 GHz to 75 GHz after 40 km single mode fiber (SMF) transmission. The photonic SSB frequency up-conversion technique shows negligible phase noise degradation. The phase noise of the up-converted RF signal at 49 GHz for an offset of 10 kHz is -93.17 dBc/Hz. Linearity analysis shows that the photonic SSB frequency up-converter has a spurious free dynamic range (SFDR) value of 79.51 dB · Hz(2/3).

  7. Carrier phase synchronization system for improved amplitude modulation and television broadcast reception

    Science.gov (United States)

    Smith, Stephen F [Loudon, TN; Moore, James A [Powell, TN

    2009-09-08

    Systems and methods are described for carrier phase synchronization for improved AM and TV broadcast reception. A method includes synchronizing the phase of a carrier frequency of a broadcast signal with the phase of a remote reference frequency. An apparatus includes a receiver to detect the phase of a reference signal; a phase comparator coupled to the reference signal-phase receiver; a voltage controlled oscillator coupled to the phase comparator; and a phase-controlled radio frequency output coupled to the voltage controlled oscillator.

  8. Multiple-Symbol Noncoherent Decoding of Uncoded and Convolutionally Codes Continous Phase Modulation

    Science.gov (United States)

    Divsalar, D.; Raphaeli, D.

    2000-01-01

    Recently, a method for combined noncoherent detection and decoding of trellis-codes (noncoherent coded modulation) has been proposed, which can practically approach the performance of coherent detection.

  9. Interleukin-1 receptor antagonist modulates the early phase of liver regeneration after partial hepatectomy in mice.

    Directory of Open Access Journals (Sweden)

    Antonino Sgroi

    Full Text Available BACKGROUND: Cytokine administration is a potential therapy for acute liver failure by reducing inflammatory responses and favour hepatocyte regeneration. The aim of this study was to evaluate the role of interleukin-1 receptor antagonist (IL-1ra during liver regeneration and to study the effect of a recombinant human IL-1ra on liver regeneration. METHODS: We performed 70%-hepatectomy in wild type (WT mice, IL-1ra knock-out (KO mice and in WT mice treated by anakinra. We analyzed liver regeneration at regular intervals by measuring the blood levels of cytokines, the hepatocyte proliferation by bromodeoxyuridin (BrdU incorporation, proliferating cell nuclear antigen (PCNA and Cyclin D1 expression. The effect of anakinra on hepatocyte proliferation was also tested in vitro using human hepatocytes. RESULTS: At 24h and at 48 h after hepatectomy, IL-1ra KO mice had significantly higher levels of pro-inflammatory cytokines (IL-6, IL-1β and MCP-1 and a reduced and delayed hepatocyte proliferation measured by BrdU incorporation, PCNA and Cyclin D1 protein levels, when compared to WT mice. IGFBP-1 and C/EBPβ expression was significantly decreased in IL-1ra KO compared to WT mice. WT mice treated with anakinra showed significantly decreased levels of IL-6 and significantly higher hepatocyte proliferation at 24h compared to untreated WT mice. In vitro, primary human hepatocytes treated with anakinra showed significantly higher proliferation at 24h compared to hepatocytes without treatment. CONCLUSION: IL1ra modulates the early phase of liver regeneration by decreasing the inflammatory stress and accelerating the entry of hepatocytes in proliferation. IL1ra might be a therapeutic target to improve hepatocyte proliferation.

  10. The Boer-Mulders and Cahn effects. Azimuthal modulations in the spin-independent SIDIS cross section at HERMES

    Energy Technology Data Exchange (ETDEWEB)

    Lamb, Rebecca Mae

    2010-08-15

    The cos {phi}{sub h} and cos 2{phi}{sub h} modulations of the spin independent semi-inclusive deep inelastic scattering cross section were measured at Hermes. These modulations are sensitive to the polarization and transverse motion of quarks within the nucleon. The Cahn effect, which contributes at subleading twist (twist-3) to cos {phi}{sub h} and twist-4 to cos 2{phi}{sub h}, is sensitive to transverse motion of quarks. The Boer-Mulders effect, which contributes at subleading twist to cos {phi}{sub h} and leading twist to cos 2{phi}{sub h}, requires non-zero transverse quark motion and is sensitive to quark polarization, effectively measuring the quark spin-orbit correlation. These modulations were measured in a fully differential way, as a function of x, y, z, and P{sub h} {sub perpendicular} {sub to} for positive and negative pions, kaons, and unidentified-hadrons produced from hydrogen and deuterium targets at Hermes. This is the the most complete measurement to date, for the first time granting access to the flavor dependent distribution and fragmentation functions that generate these moments. These measurement would not have been possible without an improved hadron-type identification algorithm for the Ring Imaging Cherenkov (RICH) detector. The EVT event-level algorithm is presented and now is the primary method used at Hermes. (orig.)

  11. The Boer-Mulders and Cahn effects. Azimuthal modulations in the spin-independent SIDIS cross section at HERMES

    International Nuclear Information System (INIS)

    Lamb, Rebecca Mae

    2010-08-01

    The cos φ h and cos 2φ h modulations of the spin independent semi-inclusive deep inelastic scattering cross section were measured at Hermes. These modulations are sensitive to the polarization and transverse motion of quarks within the nucleon. The Cahn effect, which contributes at subleading twist (twist-3) to cos φ h and twist-4 to cos 2φ h , is sensitive to transverse motion of quarks. The Boer-Mulders effect, which contributes at subleading twist to cos φ h and leading twist to cos 2φ h , requires non-zero transverse quark motion and is sensitive to quark polarization, effectively measuring the quark spin-orbit correlation. These modulations were measured in a fully differential way, as a function of x, y, z, and P h perpendicular to for positive and negative pions, kaons, and unidentified-hadrons produced from hydrogen and deuterium targets at Hermes. This is the the most complete measurement to date, for the first time granting access to the flavor dependent distribution and fragmentation functions that generate these moments. These measurement would not have been possible without an improved hadron-type identification algorithm for the Ring Imaging Cherenkov (RICH) detector. The EVT event-level algorithm is presented and now is the primary method used at Hermes. (orig.)

  12. Combined effects of potassium chloride and ethanol as mobile phase modulators on hydrophobic interaction and reversed-phase chromatography of three insulin variants.

    Science.gov (United States)

    Johansson, Karolina; Frederiksen, Søren S; Degerman, Marcus; Breil, Martin P; Mollerup, Jørgen M; Nilsson, Bernt

    2015-02-13

    The two main chromatographic modes based on hydrophobicity, hydrophobic interaction chromatography (HIC) and reversed-phase chromatography (RPC), are widely used for both analytical and preparative chromatography of proteins in the pharmaceutical industry. Despite the extensive application of these separation methods, and the vast amount of studies performed on HIC and RPC over the decades, the underlying phenomena remain elusive. As part of a systematic study of the influence of mobile phase modulators in hydrophobicity-based chromatography, we have investigated the effects of both KCl and ethanol on the retention of three insulin variants on two HIC adsorbents and two RPC adsorbents. The focus was on the linear adsorption range, separating the modulator effects from the capacity effects, but some complementary experiments at higher load were included to further investigate observed phenomena. The results show that the modulators have the same effect on the two RPC adsorbents in the linear range, indicating that the modulator concentration only affects the activity of the solute in the mobile phase, and not that of the solute-ligand complex, or that of the ligand. Unfortunately, the HIC adsorbents did not show the same behavior. However, the insulin variants displayed a strong tendency toward self-association on both HIC adsorbents; on one in particular. Since this causes peak fronting, the retention is affected, and this could probably explain the lack of congruity. This conclusion was supported by the results from the non-linear range experiments which were indicative of double-layer adsorption on the HIC adsorbents, while the RPC adsorbents gave the anticipated increased tailing at higher load. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Intensity-Modulated Whole Abdominal Radiotherapy After Surgery and Carboplatin/Taxane Chemotherapy for Advanced Ovarian Cancer: Phase I Study

    International Nuclear Information System (INIS)

    Rochet, Nathalie; Sterzing, Florian; Jensen, Alexandra D.; Dinkel, Julien; Herfarth, Klaus K.; Schubert, Kai; Eichbaum, Michael H.; Schneeweiss, Andreas; Sohn, Christof; Debus, Juergen; Harms, Wolfgang

    2010-01-01

    Purpose: To assess the feasibility and toxicity of consolidative intensity-modulated whole abdominal radiotherapy (WAR) after surgery and chemotherapy in high-risk patients with advanced ovarian cancer. Methods and Materials: Ten patients with optimally debulked ovarian cancer International Federation of Gynecology and Obstetrics Stage IIIc were treated in a Phase I study with intensity-modulated WAR up to a total dose of 30 Gy in 1.5-Gy fractions as consolidation therapy after adjuvant carboplatin/taxane chemotherapy. Treatment was delivered using intensity-modulated radiotherapy in a step-and-shoot technique (n = 3) or a helical tomotherapy technique (n = 7). The planning target volume included the entire peritoneal cavity and the pelvic and para-aortal node regions. Organs at risk were kidneys, liver, heart, vertebral bodies, and pelvic bones. Results: Intensity-modulated WAR resulted in an excellent coverage of the planning target volume and an effective sparing of the organs at risk. The treatment was well tolerated, and no severe Grade 4 acute side effects occurred. Common Toxicity Criteria Grade III toxicities were as follows: diarrhea (n = 1), thrombocytopenia (n = 1), and leukopenia (n = 3). Radiotherapy could be completed by all the patients without any toxicity-related interruption. Median follow-up was 23 months, and 4 patients had tumor recurrence (intraperitoneal progression, n = 3; hepatic metastasis, n = 1). Small bowel obstruction caused by adhesions occurred in 3 patients. Conclusions: The results of this Phase I study showed for the first time, to our knowledge, the clinical feasibility of intensity-modulated whole abdominal radiotherapy, which could offer a new therapeutic option for consolidation treatment of advanced ovarian carcinoma after adjuvant chemotherapy in selected subgroups of patients. We initiated a Phase II study to further evaluate the toxicity of this intensive multimodal treatment.

  14. Intensity-modulated whole abdominal radiotherapy after surgery and carboplatin/taxane chemotherapy for advanced ovarian cancer: phase I study.

    Science.gov (United States)

    Rochet, Nathalie; Sterzing, Florian; Jensen, Alexandra D; Dinkel, Julien; Herfarth, Klaus K; Schubert, Kai; Eichbaum, Michael H; Schneeweiss, Andreas; Sohn, Christof; Debus, Juergen; Harms, Wolfgang

    2010-04-01

    To assess the feasibility and toxicity of consolidative intensity-modulated whole abdominal radiotherapy (WAR) after surgery and chemotherapy in high-risk patients with advanced ovarian cancer. Ten patients with optimally debulked ovarian cancer International Federation of Gynecology and Obstetrics Stage IIIc were treated in a Phase I study with intensity-modulated WAR up to a total dose of 30 Gy in 1.5-Gy fractions as consolidation therapy after adjuvant carboplatin/taxane chemotherapy. Treatment was delivered using intensity-modulated radiotherapy in a step-and-shoot technique (n = 3) or a helical tomotherapy technique (n = 7). The planning target volume included the entire peritoneal cavity and the pelvic and para-aortal node regions. Organs at risk were kidneys, liver, heart, vertebral bodies, and pelvic bones. Intensity-modulated WAR resulted in an excellent coverage of the planning target volume and an effective sparing of the organs at risk. The treatment was well tolerated, and no severe Grade 4 acute side effects occurred. Common Toxicity Criteria Grade III toxicities were as follows: diarrhea (n = 1), thrombocytopenia (n = 1), and leukopenia (n = 3). Radiotherapy could be completed by all the patients without any toxicity-related interruption. Median follow-up was 23 months, and 4 patients had tumor recurrence (intraperitoneal progression, n = 3; hepatic metastasis, n = 1). Small bowel obstruction caused by adhesions occurred in 3 patients. The results of this Phase I study showed for the first time, to our knowledge, the clinical feasibility of intensity-modulated whole abdominal radiotherapy, which could offer a new therapeutic option for consolidation treatment of advanced ovarian carcinoma after adjuvant chemotherapy in selected subgroups of patients. We initiated a Phase II study to further evaluate the toxicity of this intensive multimodal treatment.

  15. Proposal of experimental setup on boiling two-phase flow on-orbit experiments onboard Japanese experiment module "KIBO"

    Science.gov (United States)

    Baba, S.; Sakai, T.; Sawada, K.; Kubota, C.; Wada, Y.; Shinmoto, Y.; Ohta, H.; Asano, H.; Kawanami, O.; Suzuki, K.; Imai, R.; Kawasaki, H.; Fujii, K.; Takayanagi, M.; Yoda, S.

    2011-12-01

    Boiling is one of the efficient modes of heat transfer due to phase change, and is regarded as promising means to be applied for the thermal management systems handling a large amount of waste heat under high heat flux. However, gravity effects on the two-phase flow phenomena and corresponding heat transfer characteristics have not been clarified in detail. The experiments onboard Japanese Experiment Module "KIBO" in International Space Station on boiling two-phase flow under microgravity conditions are proposed to clarify both of heat transfer and flow characteristics under microgravity conditions. To verify the feasibility of ISS experiments on boiling two-phase flow, the Bread Board Model is assembled and its performance and the function of components installed in a test loop are examined.

  16. Damping and fluidelastic instability in two-phase cross-flow heat exchanger tube arrays

    Science.gov (United States)

    Moran, Joaquin E.

    An experimental study was conducted to investigate damping and fluidelastic instability in tube arrays subjected to two-phase cross-flow. The purpose of this research was to improve our understanding of these phenomena and how they are affected by void fraction and flow regime. The model tube bundle had 10 cantilevered tubes in a parallel-triangular configuration, with a pitch ratio of 1.49. The two-phase flow loop used in this research utilized Refrigerant 11 as the working fluid, which better models steam-water than air-water mixtures in terms of vapour-liquid mass ratio as well as permitting phase changes due to pressure fluctuations. The void fraction was measured using a gamma densitometer, introducing an improvement over the Homogeneous Equilibrium Model (HEM) in terms of void fraction, density and velocity predictions. Three different damping measurement methodologies were implemented and compared in order to obtain a more reliable damping estimate. The methods were the traditionally used half-power bandwidth, the logarithmic decrement and an exponential fitting to the tube decay response. The decay trace was obtained by "plucking" the monitored tube from outside the test section using a novel technique, in which a pair of electromagnets changed their polarity at the natural frequency of the tube to produce resonance. The experiments showed that the half-power bandwidth produces higher damping values than the other two methods. The primary difference between the methods is caused by tube frequency shifting, triggered by fluctuations in the added mass and coupling between the tubes, which depend on void fraction and flow regime. The exponential fitting proved to be the more consistent and reliable approach to estimating damping. In order to examine the relationship between the damping ratio and mass flux, the former was plotted as a function of void fraction and pitch mass flux in an iso-contour plot. The results showed that damping is not independent of mass

  17. Energy efficiency in Norway (1997). Cross Country Comparison on Energy Efficiency Indicators - Phase 5

    Energy Technology Data Exchange (ETDEWEB)

    Alm, Leif Kristian

    2000-02-01

    This is the national report for Norway in phase 5 of the SAVE project 'Cross country comparison of energy efficiency indicators'. The report deals with energy use and energy efficiency in Norway the last 20 years, with a special emphasis on the period after 1990. A detailed sector analysis has been done, applying Laspeyres indices to attribute changes in energy use to either activity, structure or intensity (efficiency). Aggregating sectors, we have found a total efficiency improvement of maximum 7-8 TWH from 1990 to 1997. This corresponds to a saving of 0.5% per year. In the same period, final energy use per Gross Domestic Product (GDP) was reduced by approx 2.4% per year. Thereby most of the reduction in final energy intensity can not be attributed to increased energy efficiency. Almost all data are taken from official Norwegian statistics (Statistics Norway). (author)

  18. Wideband radar cross section reduction using two-dimensional phase gradient metasurfaces

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yongfeng; Qu, Shaobo; Wang, Jiafu; Chen, Hongya [College of Science, Air Force Engineering University, Xi' an, Shaanxi 710051 (China); Zhang, Jieqiu [College of Science, Air Force Engineering University, Xi' an, Shaanxi 710051 (China); Electronic Materials Research Laboratory, Key Laboratory of Ministry of Education, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China); Xu, Zhuo [Electronic Materials Research Laboratory, Key Laboratory of Ministry of Education, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China); Zhang, Anxue [School of Electronics and Information Engineering, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China)

    2014-06-02

    Phase gradient metasurface (PGMs) are artificial surfaces that can provide pre-defined in-plane wave-vectors to manipulate the directions of refracted/reflected waves. In this Letter, we propose to achieve wideband radar cross section (RCS) reduction using two-dimensional (2D) PGMs. A 2D PGM was designed using a square combination of 49 split-ring sub-unit cells. The PGM can provide additional wave-vectors along the two in-plane directions simultaneously, leading to either surface wave conversion, deflected reflection, or diffuse reflection. Both the simulation and experiment results verified the wide-band, polarization-independent, high-efficiency RCS reduction induced by the 2D PGM.

  19. Vibration of heat exchange components in liquid and two-phase cross-flow

    International Nuclear Information System (INIS)

    Pettigrew, M.J.

    1978-05-01

    Heat exchange components must be analysed at the design stage to avoid flow-induced vibration problems. This paper presents information required to formulate flow-induced vibration excitation mechanisms in liquid and two-phase cross-flow. Three basic excitation mechanisms are considered, namely: 1) fluidelastic instability, 2) periodic wake shedding, and 3) response to random flow turbulence. The vibration excitation information is deduced from vibration response data for various types of tube bundles. Sources of information are: 1) fundamental studies on tube bundles, 2) model testing, 3) field measurements, and 4) operating experiences. Fluidelastic instability is formulated in terms of dimensionless flow velocity and dimensionless damping; periodic wake shedding in terms of Strouhal number and lift coefficient; and random turbulence excitation in terms of statistical parameters of random forces. Guidelines are recommended for design purposes. (author)

  20. Energy efficiency in Norway (1996). Cross Country Comparison on Energy Efficiency Indicators, Phase 4

    Energy Technology Data Exchange (ETDEWEB)

    Alm, Leif Kristian

    1998-12-01

    This is the national report for Norway in phase 4 of the SAVE project 'Cross country comparison of energy efficiency indicators'. The report deals with energy use and energy efficiency in Norway the last 20 years, with a special emphasis on the period after 1990. Final energy use per Gross Domestic Product (GDP) was reduced by approx 2.3% per year from 1990 to 1996. Doing detailed sector analysis we are applying Laspeyres indices to attribute changes in energy use to either activity, structure or intensity. Calculating an aggregate intensity index from the sector intensities gives an average intensity reduction of 0.4% per year. Thereby most of the reduction in final energy per unit GDP are due to structural changes, and not technical improvements. Almost all data are taken from official Norwegian statistics (Statistics Norway). (author)

  1. Wideband radar cross section reduction using two-dimensional phase gradient metasurfaces

    International Nuclear Information System (INIS)

    Li, Yongfeng; Qu, Shaobo; Wang, Jiafu; Chen, Hongya; Zhang, Jieqiu; Xu, Zhuo; Zhang, Anxue

    2014-01-01

    Phase gradient metasurface (PGMs) are artificial surfaces that can provide pre-defined in-plane wave-vectors to manipulate the directions of refracted/reflected waves. In this Letter, we propose to achieve wideband radar cross section (RCS) reduction using two-dimensional (2D) PGMs. A 2D PGM was designed using a square combination of 49 split-ring sub-unit cells. The PGM can provide additional wave-vectors along the two in-plane directions simultaneously, leading to either surface wave conversion, deflected reflection, or diffuse reflection. Both the simulation and experiment results verified the wide-band, polarization-independent, high-efficiency RCS reduction induced by the 2D PGM.

  2. Pulse Pattern-Modulated Strategy for Harmonic Current Components Reduction in Three-Phase AC–DC Converters

    DEFF Research Database (Denmark)

    Davari, Pooya; Zare, Firuz; Blaabjerg, Frede

    2016-01-01

    , which need to be considered in order to be competitive in the market. Therefore, having a flexibility to meet various requirements imposed by the standard recommendations or costumer needs is at most desirable. This makes the generated harmonic current mitigation a challenging task especially with three......-phase diode bridge rectifier, which still is preferred in many power electronic systems. This paper addresses a novel current modulation strategy using a single-switch boost three-phase diode bridge rectifier. The proposed method can selectively mitigate current harmonics, which makes it suitable...

  3. Pulse pattern modulated strategy for harmonic current components reduction in three-phase AC-DC converters

    DEFF Research Database (Denmark)

    Davari, Pooya; Zare, Firuz; Blaabjerg, Frede

    2015-01-01

    , which need to be considered in order to be competitive in the market. Therefore, having a flexibility to meet various requirements imposed by the standard recommendations or costumer needs is at most desirable. This makes the generated harmonic current mitigation a challenging task especially with three......-phase diode bridge rectifier, which still is preferred in many power electronic systems. This paper addresses a novel current modulation strategy using a single-switch boost three-phase diode bridge rectifier. The proposed method can selectively mitigate current harmonics, which makes it suitable...

  4. Phase correction of electromagnetic coupling effects in cross-borehole EIT measurements

    International Nuclear Information System (INIS)

    Zhao, Y; Zimmermann, E; Wolters, B; Van Waasen, S; Huisman, J A; Treichel, A; Kemna, A

    2015-01-01

    Borehole EIT measurements in a broad frequency range (mHz to kHz) are used to study subsurface geophysical properties. However, accurate measurements have long been difficult because the required long electric cables introduce undesired inductive and capacitive coupling effects. Recently, it has been shown that such effects can successfully be corrected in the case of single-borehole measurements. The aim of this paper is to extend the previously developed correction procedure for inductive coupling during EIT measurements in a single borehole to cross-borehole EIT measurements with multiple borehole electrode chains. In order to accelerate and simplify the previously developed correction procedure for inductive coupling, a pole–pole matrix of mutual inductances is defined. This consists of the inductances of each individual chain obtained from calibration measurements and the inductances between two chains calculated from the known cable positions using numerical modelling. The new correction procedure is successfully verified with measurements in a water-filled pool under controlled conditions where the errors introduced by capacitive coupling were well-defined and could be estimated by FEM forward modelling. In addition, EIT field measurements demonstrate that the correction methods increase the phase accuracy considerably. Overall, the phase accuracy of cross-hole EIT measurements after correction of inductive and capacitive coupling is improved to better than 1 mrad up to a frequency of 1 kHz, which substantially improves our ability to characterize the frequency-dependent complex electrical resistivity of weakly polarizable soils and sediments in situ. (paper)

  5. A dosimetric comparison of two-phase adaptive intensity-modulated radiotherapy for locally advanced nasopharyngeal cancer

    OpenAIRE

    Chitapanarux, Imjai; Chomprasert, Kittisak; Nobnaop, Wannapa; Wanwilairat, Somsak; Tharavichitkul, Ekasit; Jakrabhandu, Somvilai; Onchan, Wimrak; Traisathit, Patrinee; Van Gestel, Dirk

    2015-01-01

    The purpose of this investigation was to evaluate the potential dosimetric benefits of a two-phase adaptive intensity-modulated radiotherapy (IMRT) protocol for patients with locally advanced nasopharyngeal cancer (NPC). A total of 17 patients with locally advanced NPC treated with IMRT had a second computed tomography (CT) scan after 17 fractions in order to apply and continue the treatment with an adapted plan after 20 fractions. To simulate the situation without adaptation, a hybrid plan w...

  6. Two dimension MDW OCDMA code cross-correlation for reduction of phase induced intensity noise

    Science.gov (United States)

    Ahmed, Israa Sh.; Aljunid, Syed A.; Nordin, Junita M.; Dulaimi, Layth A. Khalil Al; Matem, Rima

    2017-11-01

    In this paper, we first review 2-D MDW code cross correlation equations and table to be improved significantly by using code correlation properties. These codes can be used in the synchronous optical CDMA systems for multi access interference cancellation and maximum suppress the phase induced intensity noise. Low Psr is due to the reduction of interference noise that is induced by the 2-D MDW code PIIN suppression. High data rate causes increases in BER, requires high effective power and severely deteriorates the system performance. The 2-D W/T MDW code has an excellent system performance where the value of PIIN is suppressed as low as possible at the optimum Psr with high data bit rate. The 2-D MDW code shows better tolerance to PIIN in comparison to others with enhanced system performance. We prove by numerical analysis that the PIIN maximally suppressed by MDW code through the minimizing property of cross correlation in comparison to 2-D PDC and 2-D MQC OCDMA code.scheme systems.

  7. Two dimension MDW OCDMA code cross-correlation for reduction of phase induced intensity noise

    Directory of Open Access Journals (Sweden)

    Sh. Ahmed Israa

    2017-01-01

    Full Text Available In this paper, we first review 2-D MDW code cross correlation equations and table to be improved significantly by using code correlation properties. These codes can be used in the synchronous optical CDMA systems for multi access interference cancellation and maximum suppress the phase induced intensity noise. Low Psr is due to the reduction of interference noise that is induced by the 2-D MDW code PIIN suppression. High data rate causes increases in BER, requires high effective power and severely deteriorates the system performance. The 2-D W/T MDW code has an excellent system performance where the value of PIIN is suppressed as low as possible at the optimum Psr with high data bit rate. The 2-D MDW code shows better tolerance to PIIN in comparison to others with enhanced system performance. We prove by numerical analysis that the PIIN maximally suppressed by MDW code through the minimizing property of cross correlation in comparison to 2-D PDC and 2-D MQC OCDMA code.scheme systems.

  8. Modulated crystal structures of VII and V phases in (NH4)3H(SO4)2. I. Neutron Laue diffraction

    International Nuclear Information System (INIS)

    McIntyre, G.; Smirnov, L.S.; Baranov, A.I.; Dolbinina, V.V.; Frontas'eva, M.V.; Pavlov, S.S.; Pankratova, Yu.S.

    2010-01-01

    The study of crystal structures of VII and V phases of (NH 4 ) 3 H(SO 4 ) 2 by means of neutron Laue diffraction is carried out at temperatures from 5 to 300 K. It is found that crystal structures of VII and V phases have incommensurate modulation with different periods, and phase transition from phase VII to phase V is transition of the first type

  9. Space Vector Modulation Technique to Reduce Leakage Current of a Transformerless Three-Phase Four-Leg Photovoltaic System

    Directory of Open Access Journals (Sweden)

    F. Hasanzad

    2017-06-01

    Full Text Available Photovoltaic systems integrated to the grid have received considerable attention around the world. They can be connected to the electrical grid via galvanic isolation (transformer or without it (transformerless. Despite making galvanic isolation, low frequency transformer increases size, cost and losses. On the other hand, transformerless PV systems increase the leakage current (common-mode current, (CMC through the parasitic capacitors of the PV array. Inverter topology and switching technique are the most important parameters the leakage current depends on. As there is no need to extra hardware for switching scheme modification, it's an economical method for reducing leakage current. This paper evaluates the effect of different space vector modulation techniques on leakage current for a two-level three-phase four-leg inverter used in PV system. It proposes an efficient space vector modulation method which decreases the leakage current to below the quantity specified in VDE-0126-1-1 standard. furthermore, some other characteristics of the space vector modulation schemes that have not been significantly discussed for four-leg inverter, are considered, such as, modulation index, switching actions per period, common-mode voltage (CMV, and total harmonic distortion (THD. An extend software simulation using MATLAB/Simulink is performed to verify the effectiveness of the modulation technique.

  10. Gas-phase photoemission with soft x-rays: Cross sections and angular distributions

    International Nuclear Information System (INIS)

    Shirley, D.A.; Kobrin, P.H.; Truesdale, C.M.; Lindle, D.W.; Ferrett, T.A.; Heimann, P.A.; Becker, U.; Kerkhoff, H.G.; Southworth, S.H.

    1983-01-01

    A summary is presented of typical gas-phase photoemission studies based on synchrotron radiation in the 50-5000 eV range, using beam lines at the Stanford Synchrotron Radiation Laboratory. Three topics are addressed: atomic inner-shell photoelectron cross sections and asymmetries, correlation peaks in rare gases, and core-level shape resonances in molecules. Photoelectron cross-section σ(n iota) and asymmetry-parameter β(n iota) studies in mercury vapor at photon energies up to 270 eV (up to 600 eV for β/sub 4f/) extend coverage of these parameters to n≤5 and iota≤3. Comparison with Dirac-Slater and relativistic random-phase approximation calculations reveals systematic discrepancies. For example, distinct Cooper minima in σ(n iota) are observed but not predicted, while predicted β(n iota) values are typically too high. Correlation satellites have been studied for the K shells of helium (hν = 68-90 eV), neon (hν = 870-960 eV) and argon (hν = 3200-3320 eV). In helium the n=2 satellite peak was shown to have mainly 2p character at threshold, and its asymmetry was measured through the autoionizing resonance region. Tentative evidence was obtained that the neon satellites are less intense near threshold than in the high-energy limit, and that their intensities stay constant or decrease with increasing energy near threshold. A new satellite was observed in argon at 24.6 eV which appears to increase in intensity with energy. Molecular core-level shape resonances were observed for the first time by photoemission, yielding σ(hν) and β(hν) for core levels from 180 eV binding energy (S 2p in SF/sub 6/ and OCS) through C 1s in CO, CO/sub 2/ and CF/sub 4/, N 1s in N/sub 2/ and NO, and O 1s in CO and CO/sub 2/ to 2490 eV (S 1s in SF/sub 6/). Several conclusions can be drawn about the photoelectron and Auger cross sections and asymmetry parameters

  11. Phase synchronization in a two-mode solid state laser: Periodic modulations with the second relaxation oscillation frequency of the laser output

    International Nuclear Information System (INIS)

    Hsu, Tzu-Fang; Jao, Kuan-Hsuan; Hung, Yao-Chen

    2014-01-01

    Phase synchronization (PS) in a periodically pump-modulated two-mode solid state laser is investigated. Although PS in the laser system has been demonstrated in response to a periodic modulation with the main relaxation oscillation (RO) frequency of the free-running laser, little is known about the case of modulation with minor RO frequencies. In this Letter, the empirical mode decomposition (EMD) method is utilized to decompose the laser time series into a set of orthogonal modes and to examine the intrinsic PS near the frequency of the second RO. The degree of PS is quantified by means of a histogram of phase differences and the analysis of Shannon entropy. - Highlights: • We study the intrinsic phase synchronization in a periodically pump-modulated two-mode solid state laser. • The empirical mode decomposition method is utilized to define the intrinsic phase synchronization. • The degree of phase synchronization is quantified by a proposed synchronization coefficient

  12. Spatial light modulators for full cross-connections in optical networks

    Science.gov (United States)

    Juday, Richard D. (Inventor)

    2004-01-01

    A polarization-independent optical switch is disclosed for switching at least one incoming beam from at least one input source to at least one output drain. The switch includes a polarizing beam splitter to split each of the at least one incoming beam into a first input beam and a second input beam, wherein the first input beam and the second input beams are independently polarized; a wave plate optically coupled to the second input beam for converting the polarization of the second input beam to an appropriately polarized second input beam; a beam combiner optically coupled to the first input beam and the modified second input beam, wherein the beam combiner accepts the first input beam and the modified second input beam to produce a combined beam; the combined beam is invariant to the polarization state of the input source's polarization; and a controllable spatial light modulator optically coupled to the combined beam, wherein the combined beam is diffracted by the controllable spatial light modulator to place light at a plurality of output locations.

  13. The role of phase synchronisation between low frequency amplitude modulations in child phonology and morphology speech tasks.

    Science.gov (United States)

    Flanagan, Sheila; Goswami, Usha

    2018-03-01

    Recent models of the neural encoding of speech suggest a core role for amplitude modulation (AM) structure, particularly regarding AM phase alignment. Accordingly, speech tasks that measure linguistic development in children may exhibit systematic properties regarding AM structure. Here, the acoustic structure of spoken items in child phonological and morphological tasks, phoneme deletion and plural elicitation, was investigated. The phase synchronisation index (PSI), reflecting the degree of phase alignment between pairs of AMs, was computed for 3 AM bands (delta, theta, beta/low gamma; 0.9-2.5 Hz, 2.5-12 Hz, 12-40 Hz, respectively), for five spectral bands covering 100-7250 Hz. For phoneme deletion, data from 94 child participants with and without dyslexia was used to relate AM structure to behavioural performance. Results revealed that a significant change in magnitude of the phase synchronisation index (ΔPSI) of slower AMs (delta-theta) systematically accompanied both phoneme deletion and plural elicitation. Further, children with dyslexia made more linguistic errors as the delta-theta ΔPSI increased. Accordingly, ΔPSI between slower temporal modulations in the speech signal systematically distinguished test items from accurate responses and predicted task performance. This may suggest that sensitivity to slower AM information in speech is a core aspect of phonological and morphological development.

  14. ATLAS ITk Short Strip Prototype Module with Integrated DCDC Powering and Control Phase II Upgrade of the ATLAS Inner Tracker detector at the HL - LHC

    CERN Document Server

    Greenall, Ashley; The ATLAS collaboration

    2017-01-01

    The prototype Barrel module design, for the Phase II upgrade of the of the new Inner Tracker (ITk) detector at the LHC, has adopted an integrated low mass assembly featuring single-sided flexible circuits, with readout ASICs, glued to the silicon strip sensor. Further integration has been achieved by the attachment of module DCDC powering, HV sensor biasing switch and autonomous monitoring and control to the sensor. This low mass, integrated module approach benefits further in a reduced width stave structure to which the modules are attached. The results of preliminary electrical tests of such an integrated module will be presented.

  15. Complete modulational-instability gain spectrum of nonlinear quasi-phase-matching gratings

    DEFF Research Database (Denmark)

    Corney, Joel F.; Bang, Ole

    2004-01-01

    We consider plane waves propagating in quadratic nonlinear slab waveguides with nonlinear quasi-phasematching gratings. We predict analytically and verify numerically the complete gain spectrum for transverse modulational instability, including hitherto undescribed higher-order gain bands....

  16. Universal Sample Preparation Module for Molecular Analysis in Space, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Lynntech proposes to develop and demonstrate the ability of a compact, light-weight, and automated universal sample preparation module (USPM) to process samples from...

  17. Behavior Tracking Software Enhancement and Integration of a Feedback Module, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This Company is proposing to adapt a behavioral tracking program and feedback module specifically developed for the U.S. Army Special Forces for NASA human space...

  18. Observation Platform for Dynamic Biomedical and Biotechnology Experiments using the ISS Light Microscopy Module, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed "Observation platform for dynamic biomedical and biotechnology experiments using the ISS Light Microscopy Module" consists of a platen sized to fit the...

  19. A numerical study of aerosol influence on mixed-phase stratiform clouds through modulation of the liquid phase

    Directory of Open Access Journals (Sweden)

    G. de Boer

    2013-02-01

    Full Text Available Numerical simulations were carried out in a high-resolution two-dimensional framework to increase our understanding of aerosol indirect effects in mixed-phase stratiform clouds. Aerosol characteristics explored include insoluble particle type, soluble mass fraction, influence of aerosol-induced freezing point depression and influence of aerosol number concentration. Simulations were analyzed with a focus on the processes related to liquid phase microphysics, and ice formation was limited to droplet freezing. Of the aerosol properties investigated, aerosol insoluble mass type and its associated freezing efficiency was found to be most relevant to cloud lifetime. Secondary effects from aerosol soluble mass fraction and number concentration also alter cloud characteristics and lifetime. These alterations occur via various mechanisms, including changes to the amount of nucleated ice, influence on liquid phase precipitation and ice riming rates, and changes to liquid droplet nucleation and growth rates. Alteration of the aerosol properties in simulations with identical initial and boundary conditions results in large variability in simulated cloud thickness and lifetime, ranging from rapid and complete glaciation of liquid to the production of long-lived, thick stratiform mixed-phase cloud.

  20. CMS Pixel Upgrade for the Phase I: Module Production and Qualification

    CERN Document Server

    AUTHOR|(CDS)2078028

    2016-01-01

    The present CMS pixel detector has been designed to be fully efficient up to a LHC luminosity of $10^{34}~\\mathrm{cm}^{-2}~\\mathrm{s}^{-1}$. However, the luminosity will increase by a factor of two in the coming years. Therefore it is planned to build and install a new detector in the extended year-end technical stop (YETS) in 2016-17. Barrel pixel modules are in production since Spring/Summer 2015 in five different centers. Module production requires bump bonding, wire bonding and gluing processes to finally assemble a full module. To have a uniform performance of all modules standard qualification procedures have been developed. All modules will be subjected to 10 termal cycles between +$17^{\\circ}$C and -$25^{\\circ }$C and then electrically tested. In addition, module performance will be verified under high rate X-rays, and internal calibrate signals used for electrical tests will be calibrated in units of electrons using well defined X-ray fluorescence lines from different target materials. The qualifica...

  1. PCB 126 toxicity is modulated by cross-talk between caveolae and Nrf2 signaling

    Energy Technology Data Exchange (ETDEWEB)

    Petriello, Michael C. [Graduate Center for Toxicology, College of Medicine, University of Kentucky, Lexington, KY 40536 (United States); University of Kentucky Superfund Research Center, Lexington, KY 40536 (United States); Han, Sung Gu [University of Kentucky Superfund Research Center, Lexington, KY 40536 (United States); Department of Food Science and Biotechnology of Animal Resources, College of Animal Bioscience and Technology, Konkuk University, Seoul 143-701 (Korea, Republic of); Newsome, Bradley J. [University of Kentucky Superfund Research Center, Lexington, KY 40536 (United States); Department of Chemistry, College of Arts and Sciences, University of Kentucky, Lexington, KY 40506 (United States); Hennig, Bernhard [Graduate Center for Toxicology, College of Medicine, University of Kentucky, Lexington, KY 40536 (United States); University of Kentucky Superfund Research Center, Lexington, KY 40536 (United States); Department of Animal and Food Sciences, College of Agriculture, Food and Environment, University of Kentucky, KY 40506 (United States)

    2014-06-01

    Environmental toxicants such as polychlorinated biphenyls (PCBs) have been implicated in the promotion of multiple inflammatory disorders including cardiovascular disease, but information regarding mechanisms of toxicity and cross-talk between relevant cell signaling pathways is lacking. To examine the hypothesis that cross-talk between membrane domains called caveolae and nuclear factor (erythroid-derived 2)-like 2 (Nrf2) pathways alters PCB-induced inflammation, caveolin-1 was silenced in vascular endothelial cells, resulting in a decreased PCB-induced inflammatory response. Cav-1 silencing (siRNA treatment) also increased levels of Nrf2-ARE transcriptional binding, resulting in higher mRNA levels of the antioxidant genes glutathione s-transferase and NADPH dehydrogenase quinone-1 in both vehicle and PCB-treated systems. Along with this upregulated antioxidant response, Cav-1 siRNA treated cells exhibited decreased mRNA levels of the Nrf2 inhibitory protein Keap1 in both vehicle and PCB-treated samples. Silencing Cav-1 also decreased protein levels of Nrf2 inhibitory proteins Keap1 and Fyn kinase, especially in PCB-treated cells. Further, endothelial cells from wildtype and Cav-1 −/− mice were isolated and treated with PCB to better elucidate the role of functional caveolae in PCB-induced endothelial inflammation. Cav-1 −/− endothelial cells were protected from PCB-induced cellular dysfunction as evidenced by decreased vascular cell adhesion molecule (VCAM-1) protein induction. Compared to wildtype cells, Cav-1 −/− endothelial cells also allowed for a more effective antioxidant response, as observed by higher levels of the antioxidant genes. These data demonstrate novel cross-talk mechanisms between Cav-1 and Nrf2 and implicate the reduction of Cav-1 as a protective mechanism for PCB-induced cellular dysfunction and inflammation. - Highlights: • Reduction of caveolin-1 protein protects against polychlorinated biphenyl toxicity. • Decreasing

  2. Generation of ultra-long pure magnetization needle and multiple spots by phase modulated doughnut Gaussian beam

    Science.gov (United States)

    Udhayakumar, M.; Prabakaran, K.; Rajesh, K. B.; Jaroszewicz, Z.; Belafhal, Abdelmajid; Velauthapillai, Dhayalan

    2018-06-01

    Based on vector diffraction theory and inverse Faraday effect (IFE), the light induced magnetization distribution of a tightly focused azimuthally polarized doughnut Gaussian beam superimposed with a helical phase and modulated by an optimized multi belt complex phase filter (MBCPF) is analysed numerically. It is noted that by adjusting the radii of different rings of the complex phase filter, one can achieve many novel magnetization focal distribution such as sub wavelength scale (0.29λ) and super long (52.2λ) longitudinal magnetic probe suitable for all optical magnetic recording and the formation of multiple magnetization chain with four, six and eight sub-wavelength spherical magnetization spots suitable for multiple trapping of magnetic particles are achieved.

  3. Controlling adsorption and passivation properties of bovine serum albumin on silica surfaces by ionic strength modulation and cross-linking.

    Science.gov (United States)

    Park, Jae Hyeon; Sut, Tun Naw; Jackman, Joshua A; Ferhan, Abdul Rahim; Yoon, Bo Kyeong; Cho, Nam-Joon

    2017-03-29

    Understanding the physicochemical factors that influence protein adsorption onto solid supports holds wide relevance for fundamental insights into protein structure and function as well as for applications such as surface passivation. Ionic strength is a key parameter that influences protein adsorption, although how its modulation might be utilized to prepare well-coated protein adlayers remains to be explored. Herein, we investigated how ionic strength can be utilized to control the adsorption and passivation properties of bovine serum albumin (BSA) on silica surfaces. As protein stability in solution can influence adsorption kinetics, the size distribution and secondary structure of proteins in solution were first characterized by dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), and circular dichroism (CD) spectroscopy. A non-monotonic correlation between ionic strength and protein aggregation was observed and attributed to colloidal agglomeration, while the primarily α-helical character of the protein in solution was maintained in all cases. Quartz crystal microbalance-dissipation (QCM-D) experiments were then conducted in order to track protein adsorption onto silica surfaces as a function of ionic strength, and the measurement responses indicated that total protein uptake at saturation coverage is lower with increasing ionic strength. In turn, the QCM-D data and the corresponding Voigt-Voinova model analysis support that the surface area per bound protein molecule is greater with increasing ionic strength. While higher protein uptake under lower ionic strengths by itself did not result in greater surface passivation under subsequent physiologically relevant conditions, the treatment of adsorbed protein layers with a gluteraldehyde cross-linking agent stabilized the bound protein in this case and significantly improved surface passivation. Collectively, our findings demonstrate that ionic strength modulation influences BSA adsorption

  4. Practical use of the amplitude and phase modulation of a high-power RF pulse via feed-forward control

    International Nuclear Information System (INIS)

    Kawase, Keigo; Kato, Ryukou; Irizawa, Akinori; Isoyama, Goro; Kashiwagi, Shigeru

    2013-01-01

    A new feed-forward control system to precisely control the amplitude and phase of the pulsed RF power in an electron linear accelerator (linac) is developed to make the accelerating field constant. Fast variations and ripples in the amplitude and phase in the RF pulses are compensated by modulating the amplitude and phase in the low-level system with a variable attenuator and phase shifter. The system is innovated the overdrive technique, which is commonly used in analog circuits, to speed up the slow response of the phase shifter, while the control signals are digitally processed; thus, the method is a hybrid of analog and digital techniques. By using the new control system, we find that the peak-to-peak variations in the amplitude and phase are reduced from 11.6% to 0.4% and from 6.1 degrees to 0.3 degrees, respectively, in 7.6-μs-long RF pulses for the L-band electron linac at Osaka University. (author)

  5. FPGA Implementation of an Amplitude-Modulated Continuous-Wave Ultrasonic Ranger Using Restructured Phase-Locking Scheme

    Directory of Open Access Journals (Sweden)

    P. Sumathi

    2010-01-01

    Full Text Available An accurate ultrasonic range finder employing Sliding Discrete Fourier Transform (SDFT based restructured phase-locked loop (RPLL, which is an improved version of the recently proposed integrated phase-locking scheme (IPLL, has been expounded. This range finder principally utilizes amplitude-modulated ultrasonic waves assisted by an infrared (IR pilot signal. The phase shift between the envelope of the reference IR pilot signal and that of the received ultrasonic signal is proportional to the range. The extracted envelopes are filtered by SDFT without introducing any additional phase shift. A new RPLL is described in which the phase error is driven to zero using the quadrature signal derived from the SDFT. Further, the quadrature signal is reinforced by another cosine signal derived from a lookup table (LUT. The pulse frequency of the numerically controlled oscillator (NCO is extremely accurate, enabling fine tuning of the SDFT and RPLL also improves the lock time for the 50 Hz input signal to 0.04 s. The percentage phase error for the range 0.6 m to 6 m is about 0.2%. The VHDL codes generated for the various signal processing steps were downloaded into a Cyclone FPGA chip around which the ultrasonic ranger had been built.

  6. Electron backscatter diffraction study of deformation and recrystallization textures of individual phases in a cross-rolled duplex steel

    Energy Technology Data Exchange (ETDEWEB)

    Zaid, Md; Bhattacharjee, P.P., E-mail: pinakib@iith.ac.in

    2014-10-15

    The evolution of microstructure and texture during cross-rolling and annealing was investigated by electron backscatter diffraction in a ferritic–austenitic duplex stainless steel. For this purpose an alloy with nearly equal volume fraction of the two phases was deformed by multi-pass cross-rolling process up to 90% reduction in thickness. The rolling and transverse directions were mutually interchanged in each pass by rotating the sample by 90° around the normal direction. In order to avoid deformation induced phase transformation and dynamic strain aging, the rolling was carried out at an optimized temperature of 898 K (625 °C) at the warm-deformation range. The microstructure after cross warm-rolling revealed a lamellar structure with alternate arrangement of the bands of two phases. Strong brass and rotated brass components were observed in austenite in the steel after processing by cross warm-rolling. The ferrite in the cross warm-rolling processed steel showed remarkably strong RD-fiber (RD//< 011 >) component (001)< 011 >. The development of texture in the two phases after processing by cross warm-rolling could be explained by the stability of the texture components. During isothermal annealing of the 90% cross warm-rolling processed material the lamellar morphology was retained before collapse of the lamellar structure to the mutual interpenetration of the phase bands. Ferrite showed recovery resulting in annealing texture similar to the deformation texture. In contrast, the austenite showed primary recrystallization without preferential orientation selection leading to the retention of deformation texture. The evolution of deformation and annealing texture in the two phases of the steel was independent of one another. - Highlights: • Effect of cross warm-rolling on texture formation is studied in duplex steel. • Brass texture in austenite and (001)<110 > in ferrite are developed. • Ferrite shows recovery during annealing retaining the (001

  7. Chronic headache and comorbidities: a two-phase, population-based, cross-sectional study.

    Science.gov (United States)

    da Silva, Ariovaldo; Costa, Esther Coelho; Gomes, João Bosco; Leite, Frederico Motta; Gomez, Rodrigo Santiago; Vasconcelos, Luiz Paulo; Krymchantowski, Abouch; Moreira, Pedro; Teixeira, Antonio Lucio

    2010-09-01

    Studies using resources of a public family health program to estimate the prevalence of chronic daily headaches (CDH) are lacking. To estimate the 1-year prevalence of CDH, as well as the presence of associated psychiatric and temporomandibular disorders (TMD) comorbidities, on the entire population of a city representative of the rural area of Brazil. This was a cross-sectional, population-based, 2-phase study. In the first phase, health agents interviewed all individuals older than 10 years, in a rural area of Brazil. In the second stage, all individuals who reported headaches on 4 or more days per week were then evaluated by a multidisciplinary team. CDH were classified according to the second edition of the International Classification of Headache Disorders (ICHD-2). Medication overuse headache was diagnosed, as per the ICHD-2, after detoxification trials. Psychiatric comorbidities and TMD were diagnosed based on the DSM-IV and on the Research Diagnostic Criteria for Temporomandibular Disorders criteria, respectively. A total of 1631 subjects participated in the direct interviews. Of them, 57 (3.6%) had CDH. Chronic migraine was the most common of the CDH (21, 36.8%). Chronic tension-type headache (10, 17.5%), medication overuse headache (13, 22.8%) and probable medication overuse headache (10, 17.5%) were also common. Psychiatric disorders were observed in 38 (67.3%) of the CDH subjects. TMD were seen in 33 (58.1)% of them. The prevalence of CDH in the rural area of Brazil is similar to what has been reported in previous studies. A significant proportion of them have psychiatric comorbidities and/or TMD. In this sample, comorbidities were as frequent as reported in convenience samples from tertiary headache centers.

  8. Rapid and Robust Cross-Correlation-Based Seismic Phase Identification Using an Approximate Nearest Neighbor Method

    Science.gov (United States)

    Tibi, R.; Young, C. J.; Gonzales, A.; Ballard, S.; Encarnacao, A. V.

    2016-12-01

    The matched filtering technique involving the cross-correlation of a waveform of interest with archived signals from a template library has proven to be a powerful tool for detecting events in regions with repeating seismicity. However, waveform correlation is computationally expensive, and therefore impractical for large template sets unless dedicated distributed computing hardware and software are used. In this study, we introduce an Approximate Nearest Neighbor (ANN) approach that enables the use of very large template libraries for waveform correlation without requiring a complex distributed computing system. Our method begins with a projection into a reduced dimensionality space based on correlation with a randomized subset of the full template archive. Searching for a specified number of nearest neighbors is accomplished by using randomized K-dimensional trees. We used the approach to search for matches to each of 2700 analyst-reviewed signal detections reported for May 2010 for the IMS station MKAR. The template library in this case consists of a dataset of more than 200,000 analyst-reviewed signal detections for the same station from 2002-2014 (excluding May 2010). Of these signal detections, 60% are teleseismic first P, and 15% regional phases (Pn, Pg, Sn, and Lg). The analyses performed on a standard desktop computer shows that the proposed approach performs the search of the large template libraries about 20 times faster than the standard full linear search, while achieving recall rates greater than 80%, with the recall rate increasing for higher correlation values. To decide whether to confirm a match, we use a hybrid method involving a cluster approach for queries with two or more matches, and correlation score for single matches. Of the signal detections that passed our confirmation process, 52% were teleseismic first P, and 30% were regional phases.

  9. System tests with silicon strip module prototypes for the Phase-2-upgrade of the CMS tracker

    Energy Technology Data Exchange (ETDEWEB)

    Feld, Lutz; Karpinski, Waclaw; Klein, Katja; Preuten, Marius [I. Physikalisches Institut B, RWTH Aachen University (Germany)

    2016-07-01

    To prepare the CMS experiment for the High Luminosity LHC and its instantaneous luminosity of 5 . 10{sup 34} cm{sup -2}s{sup -1}, in the Long Shutdown 3 (around 2024) the CMS Silicon Tracker will be replaced. The Silicon Strip Modules for the new Tracker will host two vertically stacked sensors. The combination of hit information from both sensors will allow the estimation of the transverse momentum (p{sub T}) of charged particles in the module front-end. This can be used to identify hits from potential interesting high-p{sub T} tracks (above 2 GeV) for the first trigger level. The CMS Binary Chip (CBC) provides the analogue readout of two sensors and a digital section, into which the momentum discrimination is integrated. The modules will host a new DC-DC converter chain, which will allow individual powering of each module. First measurements with early prototypes on the interplay between DC-DC powering and the read-out functions of the module are presented in this talk.

  10. Social modulation of decision-making: a cross-species review

    Science.gov (United States)

    van den Bos, Ruud; Jolles, Jolle W.; Homberg, Judith R.

    2013-01-01

    Taking decisions plays a pivotal role in daily life and comprises a complex process of assessing and weighing short-term and long-term costs and benefits of competing actions. Decision-making has been shown to be affected by factors such as sex, age, genotype, and personality. Importantly, also the social environment affects decisions, both via social interactions (e.g., social learning, cooperation and competition) and social stress effects. Although everyone is aware of this social modulating role on daily life decisions, this has thus far only scarcely been investigated in human and animal studies. Furthermore, neuroscientific studies rarely discuss social influence on decision-making from a functional perspective such as done in behavioral ecology studies. Therefore, the first aim of this article is to review the available data of the influence of the social context on decision-making both from a causal and functional perspective, drawing on animal and human studies. Also, there is currently still a gap between decision-making in real life where influences of the social environment are extensive, and decision-making as measured in the laboratory, which is often done without any (deliberate) social influences. However, methods are being developed to bridge this gap. Therefore, the second aim of this review is to discuss these methods and ways in which this gap can be increasingly narrowed. We end this review by formulating future research questions. PMID:23805092

  11. Social modulation of decision-making: a cross-species review

    Directory of Open Access Journals (Sweden)

    Ruud eVan Den Bos

    2013-06-01

    Full Text Available Taking decisions plays a pivotal role in daily life and comprises a complex process of assessing and weighing short-term and long-term costs and benefits of competing actions. Decision-making has been shown to be affected by factors such as sex, age, genotype and personality. Importantly, also the social environment affects decisions, both via social interactions (e.g. social learning, cooperation and competition and social stress effects. Although everyone is aware of this social modulating role on daily life decisions, this has thus far only scarcely been investigated in human and animal studies. Furthermore, neuroscientific studies rarely discuss social influence on decision-making from a functional perspective such as done in behavioural ecology studies. Therefore, the first aim of this article is to review the available data of the influence of the social context on decision-making both from a causal and functional perspective, drawing on animal and human studies. Also, there is currently still a gap between decision-making in real life where influences of the social environment are extensive, and decision-making as measured in the laboratory, which is often done without any (deliberate social influences. However, methods are being developed to bridge this gap. Therefore, the second aim of this review is to discuss these methods and ways in which this gap can be increasingly narrowed. We end this review by formulating future research questions.

  12. Measurement of Chromatic Dispersion using the Baseband Radio-Frequency Response of a Phase-Modulated Analog Optical Link Employing a Reference Fiber

    National Research Council Canada - National Science Library

    McKinney, Jason D; Diehl, John

    2007-01-01

    In this work we demonstrate a new technique for measuring the chromatic dispersion of an optical fiber using the baseband RF response of a phase-modulated analog optical link in concert with a well...

  13. Optical phase-modulated radio-over-fiber links with k-means algorithm for digital demodulation of 8PSK subcarrier multiplexed signals

    DEFF Research Database (Denmark)

    Guerrero Gonzalez, Neil; Zibar, Darko; Yu, Xianbin

    2010-01-01

    A k-means algorithm for phase recovery of three, 50 Mbaud, 8PSK subcarrier multiplexed signals at 5 GHz for optical phase-modulated radio-over-fiber is proposed and experimentally demonstrated after 40 km of single mode fiber transmission......A k-means algorithm for phase recovery of three, 50 Mbaud, 8PSK subcarrier multiplexed signals at 5 GHz for optical phase-modulated radio-over-fiber is proposed and experimentally demonstrated after 40 km of single mode fiber transmission...

  14. Multiband Carrierless Amplitude Phase Modulation for High Capacity Optical Data Links

    DEFF Research Database (Denmark)

    Iglesias Olmedo, Miguel; Zuo, Tianjian; Jensen, Jesper Bevensee

    2014-01-01

    . The reported experiment uses MultiCAP to achieve 102.4 Gb/s transmission, corresponding to a data payload of 95.2 Gb/s error free transmission by using a 7% forward error correction (FEC) code. The signal is successfully recovered after 15 km of standard single mode fiber (SSMF) in a system limited by a 3 d......Short range optical data links are experiencing bandwidth limitations making it very challenging to cope with the growing data transmission capacity demands. Parallel optics appears as a valid short-term solution. It is, however, not a viable solution in the long-term because of its complex optical...... packaging. Therefore, increasing effort is now put into the possibility of exploiting higher order modulation formats with increased spectral efficiency and reduced optical transceiver complexity. As these type of links are based on intensity modulation and direct detection, modulation formats relying...

  15. Modulation Schemes of Multi-phase Three-Level Z-Source Inverters

    DEFF Research Database (Denmark)

    Gao, F.; Loh, P.C.; Blaabjerg, Frede

    2007-01-01

    different modulation requirement and output performance. For clearly illustrating the detailed modulation process, time domain analysis instead of the traditional multi-dimensional space vector demonstration is assumed which reveals the right way to insert shoot-through durations in the switching sequence...... with minimal commutation count. Lastly, the theoretical findings are verified in Matlab/PLECS simulation and experimentally using constructed laboratory prototypes.......This paper investigates the modulation schemes of three-level multiphase Z-source inverters with either two Z-source networks or single Z-source network connected between the dc sources and inverter circuitry. With the proper offset added for achieving both desired four-leg operation and optimized...

  16. 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...

  17. Experimental 2.5 Gbit/s QPSK WDM coherent phase modulated radio-over-fibre link with digital demodulation by a K-means algorithm

    DEFF Research Database (Denmark)

    Guerrero Gonzalez, Neil; Caballero Jambrina, Antonio; Amaya Fernández, Ferney Orlando

    2009-01-01

    Highest reported bit rate of 2.5 Gbit/s for optically phase modulated radio-over-fibre link employing coherent detection is demonstrated. Demodulation of 3·2.5 Gbit/s QPSK modulated WDM channels, is achieved after 79km of transmission through deployed fiber....

  18. Research Leading to High Throughput Processing of Thin-Film CdTe PV Module: Phase I Annual Report, October 2003 (Revised)

    Energy Technology Data Exchange (ETDEWEB)

    Powell, R. C.; Meyers, P. V.

    2004-02-01

    Work under this subcontract contributes to the overall manufacturing operation. During Phase I, average module efficiency on the line was improved from 7.1% to 7.9%, due primarily to increased photocurrent resulting from a decrease in CdS thickness. At the same time, production volume for commercial sale increased from 1.5 to 2.5 MW/yr. First Solar is committed to commercializing CdTe-based thin-film photovoltaics. This commercialization effort includes a major addition of floor space and equipment, as well as process improvements to achieve higher efficiency and greater durability. This report presents the results of Phase I of the subcontract entitled''Research Leading to High Throughput Processing of Thin-Film CdTe PV Modules.'' The subcontract supports several important aspects needed to begin high-volume manufacturing, including further development of the semiconductor deposition reactor, advancement of accelerated life testing methods and understanding, and improvements to th e environmental, health, and safety programs. Progress in the development of the semiconductor deposition reactor was made in several areas. First, a new style of vapor transport deposition distributor with simpler operational behavior and the potential for improved cross-web uniformity was demonstrated. Second, an improved CdS feed system that will improve down-web uniformity was developed. Third, the core of a numerical model of fluid and heat flow within the distributor was developed, including flow in a 3-component gas system at high temperature and low pressure and particle sublimation.

  19. Common-Mode Voltage Reduction of Three-to-Five Phase Indirect Matrix Converters with Zero-Current Vector Modulation

    DEFF Research Database (Denmark)

    Zhang, Guanguan; Yang, Jian; Yang, Yongheng

    2017-01-01

    In order to reduce the Common-Mode Voltage (CMV) in three-to-five phase indirect matrix converters, three improved Space Vector Pulse Width Modulation (SVPWM) methods are proposed and discussed. The improved modulation schemes are achieved by reorganizing zero vectors from the inversion stage......) in the inversion stage, which results in a large amount of third-order harmonics in output currents. In addition, the method that utilizes two adjacent active current vectors (ACVs) and the method that uses two non-adjacent ACVs in the rectification stage have the same CMV peak value. By contrast, the latter...... achieves a lower Total Harmonic Distortion (THD) level of the output currents. Simulation results verify the effectiveness of the proposed methods....

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

    DEFF Research Database (Denmark)

    Behrouzian, Ehsan; Bongiorno, Massimo; Teodorescu, Remus

    2014-01-01

    to provide more uniform power distribution among the cells, two different methods called, a) carrier swapping and b) non-integer frequency modulation ratio are studied. In particular, it is shown that the selection of a non-integer frequency modulation ratio helps in providing a more uniform power......The purpose of this paper is to investigate the impact of switching harmonics on the instantaneous power that flows in the cells of a chain-link based STATCOM when using Phase-Shifted PWM. Two different cases are investigated for the converter cells: low, and high switching frequency. It is shown...... that any deviation from the ideal conditions lead to undesired harmonics, which will impact the charge of the dc capacitors. It is also shown that for low switching frequencies, cells voltage sideband harmonics interact with baseband harmonics of the current and causes extra source of unbalance. In order...

  1. Performance evaluation and optimization of multiband phase-modulated radio over IsOWC link with balanced coherent homodyne detection

    Science.gov (United States)

    Zong, Kang; Zhu, Jiang

    2018-04-01

    In this paper, we present a multiband phase-modulated (PM) radio over intersatellite optical wireless communication (IsOWC) link with balanced coherent homodyne detection. The proposed system can provide the transparent transport of multiband radio frequency (RF) signals with higher linearity and better receiver sensitivity than intensity modulated with direct detection (IM/DD) system. The expressions of RF gain, noise figure (NF) and third-order spurious-free dynamic range (SFDR) are derived considering the third-order intermodulation product and amplifier spontaneous emission (ASE) noise. The optimal power of local oscillator (LO) optical signal is also derived theoretically. Numerical results for RF gain, NF and third-order SFDR are given for demonstration. Results indicate that the gain of the optical preamplifier and the power of LO optical signal should be optimized to obtain the satisfactory performance.

  2. Quasi-Coherent Noise Jamming to LFM Radar Based on Pseudo-random Sequence Phase-modulation

    Directory of Open Access Journals (Sweden)

    N. Tai

    2015-12-01

    Full Text Available A novel quasi-coherent noise jamming method is proposed against linear frequency modulation (LFM signal and pulse compression radar. Based on the structure of digital radio frequency memory (DRFM, the jamming signal is acquired by the pseudo-random sequence phase-modulation of sampled radar signal. The characteristic of jamming signal in time domain and frequency domain is analyzed in detail. Results of ambiguity function indicate that the blanket jamming effect along the range direction will be formed when jamming signal passes through the matched filter. By flexible controlling the parameters of interrupted-sampling pulse and pseudo-random sequence, different covering distances and jamming effects will be achieved. When the jamming power is equivalent, this jamming obtains higher process gain compared with non-coherent jamming. The jamming signal enhances the detection threshold and the real target avoids being detected. Simulation results and circuit engineering implementation validate that the jamming signal covers real target effectively.

  3. Commensurately modulated 1/4 and 1/5 phases of deuterated betaine calcium chloride dihydrate: a neutron structural study

    International Nuclear Information System (INIS)

    Hernandez, O.; Cousson, A.; Kiat, J.M.; Ecole Centrale des Arts et Manufactures, 92 - Chatenay-Malabry; Paulus, W.; Technische Hochschule Aachen; Ezpeleta, J.M.; Zuniga, F.J.

    1999-01-01

    The structures of the commensurate 1/4 and 1/5 phases of the displacively modulated compound D-BCCD [deuterated betaine (trimethylammonioacetate) calcium chloride dihydrate, i.e. (CD 3 ) 3 NCD 2 COOCaCl 2 (D 2 O) 2 or CaCl 2 x C 5 D 11 NO 2 x 2D 2 O] have been determined by single-crystal neutron diffraction at 100 and 68 K, respectively. The structural model of the 1/4 phase is found to be quite different from that obtained previously from X-ray diffraction data of the hydrogenated compound. This discrepancy comes from the fact that X-ray irradiation induces in this compound an unusual time-dependent decrease of the intensity of high-order satellite diffraction peaks. As a consequence and due to the commensurate nature of the phases investigated, X-ray diffraction failed to detect the large anharmonicity of the structural modulation which is clearly present in the two structures determined by neutron diffraction. (orig.)

  4. Fringe counting method for synthetic phase with frequency-modulated laser diodes

    International Nuclear Information System (INIS)

    Onodera, Ribun; Sakuyama, Munechika; Ishii, Yukihiro

    2007-01-01

    Fringe counting method with laser diodes (LDs) for displacement measurement has been constructed. Two LDs are frequency modulated by mutually inverted sawtooth currents on an unbalanced two-beam interferometer. The mutually inverted sawtooth-current modulation of LDs produces interference fringe signals with opposite signs for respective wavelengths. The two fringe signals are fed to an electronic mixer to produce a synthetic fringe signal with a reduced sensitivity to the synthetic wavelength. Synthetic fringe pulses derived from the synthetic fringe signal make a fringe counting system possible for faster movement of the tested mirror

  5. Random excitation forces in tube bundles subjected to two-phase cross-flow

    International Nuclear Information System (INIS)

    Taylor, C.E.; Pettigrew, M.J.; Currie, I.G.

    1996-01-01

    Data from two experimental programs have been analyzed to determine the characteristics of the random excitation forces associated with two-phase cross-flow in tube bundles. Large-scale air-water flow loops in France and Canada were used to generate the data. Tests were carried out on cantilevered, clamped-pinned, and clamped-clamped tubes in normal-square, parallel-triangular, and normal-triangular configurations. Either strain gages or force transducers were used to measure the vibration response of a centrally located tube as the tue array was subjected to a wide range of void fractions and flow rates. Power spectra were analyzed to determine the effect of parameters such as tube diameter, frequency, flow rate, void fraction, and flow regime on the random excitation forces. Normalized expressions for the excitation force power spectra were found to be flow-regime dependent. In the churn flow regime, flow rate and void fraction had very little effect on the magnitude of the excitation forces. In the bubble-plug flow regime, the excitation forces increased rapidly with flow rate and void fraction

  6. Phase of the annual modulation as a tool for determining the mass of the weakly interacting massive particle

    International Nuclear Information System (INIS)

    Lewis, Matthew J.; Freese, Katherine

    2004-01-01

    The count rate of weakly interacting massive particle (WIMP) dark matter candidates in direct detection experiments experiences an annual modulation due to the Earth's motion around the Sun. In the standard isothermal halo model, the signal peaks near June 2nd at high recoil energies; however, the signal experiences a phase reversal and peaks in December at low energy recoils. We show that this phase reversal may be used to determine the WIMP mass. If an annual modulation were observed with the usual phase (i.e., peaking on June 2nd) in the lowest accessible energy recoil bins of the DAMA, CDMS-II, CRESST-II, EDELWEISS-II, GENIUS-TF, ZEPLIN-II, XENON, or ZEPLIN-IV detectors, one could immediately place upper bounds on the WIMP mass of 103, 48, 6, 97, 10, 52, 29, and 29 GeV, respectively. In addition, detectors with adequate energy resolution and sufficiently low recoil energy thresholds may determine the crossover recoil energy at which the phase reverses, thereby obtaining an independent measurement of the WIMP mass. We study the capabilities of various detectors, and find that CRESST-II, ZEPLIN-II, and GENIUS-TF should be able to observe the phase reversal in a few years of runtime, and can thus determine the mass of the WIMP if it is O(100 GeV). Xenon based detectors with 1000 kg (XENON and ZEPLIN-IV) and with energy recoil thresholds of a few keV require 25 kg yr exposure, which will be readily attained in upcoming experiments

  7. Feedforward and feedback control of locked mode phase and rotation in DIII-D with application to modulated ECCD experiments

    Science.gov (United States)

    Choi, W.; La Haye, R. J.; Lanctot, M. J.; Olofsson, K. E. J.; Strait, E. J.; Sweeney, R.; Volpe, F. A.; The DIII-D Team

    2018-03-01

    The toroidal phase and rotation of otherwise locked magnetic islands of toroidal mode number n  =  1 are controlled in the DIII-D tokamak by means of applied magnetic perturbations of n  =  1. Pre-emptive perturbations were applied in feedforward to ‘catch’ the mode as it slowed down and entrain it to the rotating field before complete locking, thus avoiding the associated major confinement degradation. Additionally, for the first time, the phase of the perturbation was optimized in real-time, in feedback with magnetic measurements, in order for the mode’s phase to closely match a prescribed phase, as a function of time. Experimental results confirm the capability to hold the mode in a given fixed-phase or to rotate it at up to 20 Hz with good uniformity. The control-coil currents utilized in the experiments agree with the requirements estimated by an electromechanical model. Moreover, controlled rotation at 20 Hz was combined with electron cyclotron current drive (ECCD) modulated at the same frequency. This is simpler than regulating the ECCD modulation in feedback with spontaneous mode rotation, and enables repetitive, reproducible ECCD deposition at or near the island O-point, X-point and locations in between, for careful studies of how this affects the island stability. Current drive was found to be radially misaligned relative to the island, and resulting growth and shrinkage of islands matched expectations of the modified Rutherford equation for some discharges presented here. Finally, simulations predict the as designed ITER 3D coils can entrain a small island at sub-10 Hz frequencies.

  8. Dynamic modulation of corticospinal excitability and short-latency afferent inhibition during onset and maintenance phase of selective finger movement.

    Science.gov (United States)

    Cho, Hyun Joo; Panyakaew, Pattamon; Thirugnanasambandam, Nivethida; Wu, Tianxia; Hallett, Mark

    2016-06-01

    During highly selective finger movement, corticospinal excitability is reduced in surrounding muscles at the onset of movement but this phenomenon has not been demonstrated during maintenance of movement. Sensorimotor integration may play an important role in selective movement. We sought to investigate how corticospinal excitability and short-latency afferent inhibition changes in active and surrounding muscles during onset and maintenance of selective finger movement. Using transcranial magnetic stimulation (TMS) and paired peripheral stimulation, input-output recruitment curve and short-latency afferent inhibition (SAI) were measured in the first dorsal interosseus and abductor digiti minimi muscles during selective index finger flexion. Motor surround inhibition was present only at the onset phase, but not at the maintenance phase of movement. SAI was reduced at onset but not at the maintenance phase of movement in both active and surrounding muscles. Our study showed dynamic changes in corticospinal excitability and sensorimotor modulation for active and surrounding muscles in different movement states. SAI does not appear to contribute to motor surround inhibition at the movement onset phase. Also, there seems to be different inhibitory circuit(s) other than SAI for the movement maintenance phase in order to delineate the motor output selectively when corticospinal excitability is increased in both active and surrounding muscles. This study enhances our knowledge of dynamic changes in corticospinal excitability and sensorimotor interaction in different movement states to understand normal and disordered movements. Published by Elsevier Ireland Ltd.

  9. Nonsymmorphic cubic Dirac point and crossed nodal rings across the ferroelectric phase transition in LiOsO3

    Science.gov (United States)

    Yu, Wing Chi; Zhou, Xiaoting; Chuang, Feng-Chuan; Yang, Shengyuan A.; Lin, Hsin; Bansil, Arun

    2018-05-01

    Crystalline symmetries can generate exotic band-crossing features, which can lead to unconventional fermionic excitations with interesting physical properties. We show how a cubic Dirac point—a fourfold-degenerate band-crossing point with cubic dispersion in a plane and a linear dispersion in the third direction—can be stabilized through the presence of a nonsymmorphic glide mirror symmetry in the space group of the crystal. Notably, the cubic Dirac point in our case appears on a threefold axis, even though it has been believed previously that such a point can only appear on a sixfold axis. We show that a cubic Dirac point involving a threefold axis can be realized close to the Fermi level in the nonferroelectric phase of LiOsO3. Upon lowering temperature, LiOsO3 has been shown experimentally to undergo a structural phase transition from the nonferroelectric phase to the ferroelectric phase with spontaneously broken inversion symmetry. Remarkably, we find that the broken symmetry transforms the cubic Dirac point into three mutually crossed nodal rings. There also exist several linear Dirac points in the low-energy band structure of LiOsO3, each of which is transformed into a single nodal ring across the phase transition.

  10. Afferent-mediated modulation of the soleus muscle activity during the stance phase of human walking

    DEFF Research Database (Denmark)

    Nazarena, Mazzaro; Grey, Michael James; do Nascimento, Omar Feix

    2006-01-01

    The aim of this study was to investigate the contribution of proprioceptive feedback to the amplitude modulation of the soleus muscle activity during human walking. We have previously shown that slow-velocity, small-amplitude ankle dorsiflexion enhancements and reductions applied during the stance...

  11. Properties of a novel radiophotoluminescent readout system using a cw modulated UV laser diode and phase-sensitive technique

    International Nuclear Information System (INIS)

    Zhao, C.; Kurobori, T.; Miyamoto, Y.; Yamamoto, T.

    2011-01-01

    We have proposed and constructed a novel readout system for measuring a dose-dependent radiophotoluminescence (RPL) signal of a silver-activated phosphate glass dosimeter. The present reader consists of a modulated continuous-wave (cw) ultraviolet (UV) laser diode at 375 nm as an excitation and a phase-sensitive technique using a lock-in amplifier. Preliminary results using a home-made reader are compared with those of the conventional technique based on a combination of a pulsed UV N 2 laser excitation at 337 nm and a photon counting system.

  12. 10Gb/s Ultra-Wideband Wireless Transmission Based on Multi-Band Carrierless Amplitude Phase Modulation

    DEFF Research Database (Denmark)

    Puerta Ramírez, Rafael; Rommel, Simon; Vegas Olmos, Juan José

    2016-01-01

    In this paper, for the first time, a record UWB transmission of 10Gb/s is experimentally demonstrated employing a multi-band approach of carrierless amplitude phase modulation (MultiCAP). The proposed solution complies with the restrictions on the effective radiated power established by both...... the United States Federal Communications Commission and the European Electronic Communications Committee, achieving a BER below the limit for a 7% overhead FEC of 3.8 · 10−3 up to respective wireless distances of 3.5m and 2m....

  13. Self-pulsing in a 2 km single-mode fiber with the seed source broadened via WNS phase modulation

    Science.gov (United States)

    Zha, Congwen; Sun, Yinhong; Wang, Yanshan; Li, Tenglong; Peng, Wanjing; Ma, Yi; Zhang, Kai

    2018-03-01

    The seed source with spectral linewidth broadening via phase modulation is potential to achieve the higher output power with effective SBS suppression. However, self-pulsing from the amplifier output is harmful. In this work, we study the self-pulsing characteristics in a long single-mode fiber with lower self-pulsing threshold instead of the high power amplifier. We provide a powerful experimental support for the self-pulsing mechanism in high-power narrow-linewidth fiber lasers, which is important for further output power scaling.

  14. Influence of cross-sectional geometry on the sensitivity and hysteresis of liquid-phase electronic pressure sensors

    Science.gov (United States)

    Park, Yong-Lae; Tepayotl-Ramirez, Daniel; Wood, Robert J.; Majidi, Carmel

    2012-11-01

    Cross-sectional geometry influences the pressure-controlled conductivity of liquid-phase metal channels embedded in an elastomer film. These soft microfluidic films may function as hyperelastic electric wiring or sensors that register the intensity of surface pressure. As pressure is applied to the elastomer, the cross-section of the embedded channel deforms, and the electrical resistance of the channel increases. In an effort to improve sensitivity and reduce sensor nonlinearity and hysteresis, we compare the electrical response of 0.25 mm2 channels with different cross-sectional geometries. We demonstrate that channels with a triangular or concave cross-section exhibit the least nonlinearity and hysteresis over pressures ranging from 0 to 70 kPa. These experimental results are in reasonable agreement with predictions made by theoretical calculations that we derive from elasticity and Ohm's Law.

  15. Simulated performance of an acoustic modem using phase-modulated signals in a time-varying, shallow-water environment

    DEFF Research Database (Denmark)

    Bjerrum-Niese, Christian; Jensen, Leif Bjørnø

    1996-01-01

    and dynamic multipath channel. Multipath arrivals at the receiver cause phase distortion and fading of the signal envelope. Yet, for extreme ratios of range to depth, the delays of multipath arrivals decrease, and the channel impulse response coherently contributes energy to the signal at short delays......Underwater acoustic modems using coherent modulation, such as phase-shift keying, have proven to efficiently exploit the bandlimited underwater acoustical communication channel. However, the performance of an acoustic modem, given as maximum range and data and error rate, is limited in the complex...... relative to the first arrival, while longer delays give rise to intersymbol interference. Following this, the signal-to-multipath ratio (SMR) is introduced. It is claimed that the SMR determines the performance rather than the signal-to-noise ratio (SNR). Using a ray model including temporal variations...

  16. Phase III study of the European Organisation for Research and Treatment of Cancer satisfaction with cancer care core questionnaire (EORTC PATSAT-C33) and specific complementary outpatient module (EORTC OUT-PATSAT7).

    Science.gov (United States)

    Brédart, A; Anota, A; Young, T; Tomaszewski, K A; Arraras, J I; Moura De Albuquerque Melo, H; Schmidt, H; Friend, E; Bergenmar, M; Costantini, A; Vassiliou, V; Hureaux, J; Marchal, F; Tomaszewska, I M; Chie, W-C; Ramage, J; Beaudeau, A; Conroy, T; Bleiker, E; Kulis, D; Bonnetain, F; Aaronson, N K

    2018-01-01

    Advances in cancer care delivery require revision and further development of questionnaires assessing patients' perceived quality of care. This study pre-tested the revised EORTC satisfaction with cancer care core questionnaire applicable in both the cancer inpatient and outpatient settings, and its new, outpatient-specific complementary module. The process of revision, development of the extended application, and pre-testing of these questionnaires was based on phases I to III of the "EORTC Quality of Life Group Module Development Guidelines." In phase III, patients in 11 countries in four European regions, South America and Asia completed provisional versions of the questionnaires. Fifty-seven relevant issues selected from literature reviews and input from experts were operationalized into provisional items, and subsequently translated into ten languages. Assessment of understanding, acceptability, redundancy and relevance by patients (n = 151) from oncology inpatient wards, and outpatient chemotherapy, radiotherapy and consultation settings, led to retention of, deletion of and merging of 40, 14 and 6 items respectively. Cronbach's alpha coefficients for hypothesized questionnaire scales were above 0.80. Our results provide preliminary support for the 33-item EORTC Satisfaction with cancer care core questionnaire and the 7-item complementary module specific for the outpatient care setting. A large scale phase IV cross-cultural psychometric study is now underway. © 2017 John Wiley & Sons Ltd.

  17. Cross-Language Modulation of Visual Attention Span: An Arabic-French-Spanish Comparison in Skilled Adult Readers.

    Science.gov (United States)

    Awadh, Faris H R; Phénix, Thierry; Antzaka, Alexia; Lallier, Marie; Carreiras, Manuel; Valdois, Sylviane

    2016-01-01

    In delineating the amount of orthographic information that can be processed in parallel during a single fixation, the visual attention (VA) span acts as a key component of the reading system. Previous studies focused on the contribution of VA span to normal and pathological reading in monolingual and bilingual children from different European languages, without direct cross-language comparison. In the current paper, we explored modulations of VA span abilities in three languages -French, Spanish, and Arabic- that differ in transparency, reading direction and writing systems. The participants were skilled adult readers who were native speakers of French, Spanish or Arabic. They were administered tasks of global and partial letter report, single letter identification and text reading. Their VA span abilities were assessed using tasks that require the processing of briefly presented five consonant strings (e.g., R S H F T). All five consonants had to be reported in global report but a single cued letter in partial report. Results showed that VA span was reduced in Arabic readers as compared to French or Spanish readers who otherwise show a similar high performance in the two report tasks. The analysis of VA span response patterns in global report showed a left-right asymmetry in all three languages. A leftward letter advantage was found in French and Spanish but a rightward advantage in Arabic. The response patterns were symmetric in partial report, regardless of the language. Last, a significant relationship was found between VA span abilities and reading speed but only for French. The overall findings suggest that the size of VA span, the shape of VA span response patterns and the VA Span-reading relationship are modulated by language-specific features.

  18. Cross-language modulation of visual attention span: An Arabic-French-Spanish comparison in adult skilled readers.

    Directory of Open Access Journals (Sweden)

    Faris Haroon Rasheed Awadh

    2016-03-01

    Full Text Available In delineating the amount of orthographic information that can be processed in parallel during a single fixation, the visual attention (VA span acts as a key component of the reading system. Previous studies focused on the contribution of VA span to normal and pathological reading in monolingual and bilingual children from different European languages, without direct cross-language comparison. In the current paper, we explored modulations of VA span abilities in three languages --French, Spanish and Arabic-- that differ in transparency, reading direction and writing systems. The participants were adult skilled readers who were native speakers of French, Spanish or Arabic. They were administered tasks of global and partial letter report, single letter identification and text reading. Their VA span abilities were assessed using tasks that require the processing of briefly presented 5 consonant strings (e.g., R S H F T. All five consonants had to be reported in global report but a single cued letter in partial report. Results showed that the VA span was reduced in Arabic readers as compared to French or Spanish readers who otherwise show a similar high performance in the two report tasks. The analysis of VA span response patterns in global report showed a left-right asymmetry in all three languages. A leftward letter advantage was found in French and Spanish but a rightward advantage in Arabic. The response patterns were symmetric in partial report, regardless of the language. Last, a significant relationship was found between visual attention span abilities and reading speed but only for French. The overall findings suggest that the size of VA span, the shape of VA span response patterns and the VA Span-reading relationship are modulated by language-specific features.

  19. Laser frequency stabilisation by the Pound - Drever - Hall method using an acousto-optic phase modulator operating in the pure Raman - Nath diffraction regime

    International Nuclear Information System (INIS)

    Baryshev, Vyacheslav N

    2012-01-01

    Frequency stabilisation of diode laser radiation has been implemented by the Pound - Drever - Hall method using a new acousto-optic phase modulator, operating in the pure Raman - Nath diffraction regime. It is experimentally shown that, as in the case of saturated-absorption spectroscopy in atomic vapour, the spatial divergence of the frequency-modulated output spectrum of this modulator does not interfere with obtaining error signals by means of heterodyne frequency-modulation spectroscopy with a frequency discriminator based on a high-Q Fabry - Perot cavity with finesse of several tens of thousands.

  20. Suitability of an MRMCE (multi-resolution minimum cross entropy) algorithm for online monitoring of a two-phase flow

    International Nuclear Information System (INIS)

    Wang, Qi; Wang, Huaxiang; Xin, Shan

    2011-01-01

    The flow regimes are important characteristics to describe two-phase flows, and measurement of two-phase flow parameters is becoming increasingly important in many industrial processes. Computerized tomography (CT) has been applied to two-phase/multi-phase flow measurement in recent years. Image reconstruction of CT often involves repeatedly solving large-dimensional matrix equations, which are computationally expensive, especially for the case of online flow regime identification. In this paper, minimum cross entropy reconstruction based on multi-resolution processing (MRMCE) is presented for oil–gas two-phase flow regime identification. A regularized MCE solution is obtained using the simultaneous multiplicative algebraic reconstruction technique (SMART) at a coarse resolution level, where important information on the reconstructed image is contained. Then, the solution in the finest resolution is obtained by inverse fast wavelet transformation. Both computer simulation and static/dynamic experiments were carried out for typical flow regimes. Results obtained indicate that the proposed method can dramatically reduce the computational time and improve the quality of the reconstructed image with suitable decomposition levels compared with the single-resolution maximum likelihood expectation maximization (MLEM), alternating minimization (AM), Landweber, iterative least square technique (ILST) and minimum cross entropy (MCE) methods. Therefore, the MRMCE method is suitable for identification of dynamic two-phase flow regimes

  1. Advanced Nongray Radiation Module in the LOCI Framework for Combustion CFD, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Radiative heat fluxes are important in the design of launch vehicles for Project Constellation. In this Phase II STTR, CFDRC and its partner Mississippi State...

  2. Silicon-Carbide (SIC) Multichip Power Modules (MCPMS) For Power Building Block Applications, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase I project seeks to prove the feasibility of developing high power density modular power electronic building blocks...

  3. Module Production and Qualification for the Phase I Upgrade of the CMS Pixel Detector

    CERN Document Server

    AUTHOR|(CDS)2086689

    2015-01-01

    After consolidation of the LHC in 2013/14 its centre-of-mass energy will increase to 13TeV and the luminosity will reach $2 \\cdot 10^{34}\\, \\textnormal{cm}^{-2} \\textnormal{s}^{-1}$, which is twice the design luminosity. The latter will result in more simultaneous particle collisions, which would significantly increase the dead time of the current readout chip of the CMS pixel detector. Therefore the entire CMS pixel detector is replaced in 2016/17 and a new digital readout with larger buffers will be used to handle increasing pixel hit rates. An additional fourth barrel-layer provides more space points to improve track reconstruction. Half of the required modules for layer four is being produced at Karlsruhe Institute of Technology (KIT). This poster deals with the smallest discrete subunit of the pixel detector, the module and its assembly process. Moreover first production experience will be shown.

  4. Light modulation in phase change disordered metamaterial - A smart cermet concept

    OpenAIRE

    Kumar , Sunil; Maury , Francis; Bahlawane , Naoufal

    2017-01-01

    International audience; Cermet coatings are popular solar selective absorbers as they allow capturing most of the solar energywhile minimising radiative losses. Embedded metallic nanoparticles in dielectric matrices promotemultiple internal reflection of light and provide an overall low emissivity. VO2 in the metamaterial stateis regarded in this study as a responsive mixed phase comprising metallic rutile VO2 inclusions insemiconducting monoclinic VO2 phase mimicking cermet. The smart cermet...

  5. Detection of microcalcifications by characteristic magnetic susceptibility effects using MR phase image cross-correlation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Baheza, Richard A. [Department of Biomedical Engineering and Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee 37232-2310 (United States); Welch, E. Brian [Institute of Imaging Science and Departments of Radiology and Radiological Sciences and Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37232-2310 (United States); Gochberg, Daniel F. [Institute of Imaging Science and Departments of Radiology and Radiological Sciences, and Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37232-2310 (United States); Sanders, Melinda [Department of Pathology, Vanderbilt University, Nashville, Tennessee 37232-2310 (United States); Harvey, Sara [Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee 37232-2310 (United States); Gore, John C. [Institute of Imaging Science and Departments of Biomedical Engineering, Radiology and Radiological Sciences, Physics and Astronomy, and Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37232-2310 (United States); Yankeelov, Thomas E., E-mail: thomas.yankeelov@vanderbilt.edu [Institute of Imaging Science and Departments of Radiology and Radiological Sciences, Biomedical Engineering, Physics and Astronomy, and Cancer Biology, Vanderbilt University, Nashville, Tennessee 37232-2310 (United States)

    2015-03-15

    Purpose: To develop and evaluate a new method for detecting calcium deposits using their characteristic magnetic susceptibility effects on magnetic resonance (MR) images at high fields and demonstrate its potential in practice for detecting breast microcalcifications. Methods: Characteristic dipole signatures of calcium deposits were detected in magnetic resonance phase images by computing the cross-correlation between the acquired data and a library of templates containing simulated phase patterns of spherical deposits. The influence of signal-to-noise ratio and various other MR parameters on the results were assessed using simulations and validated experimentally. The method was tested experimentally for detection of calcium fragments within gel phantoms and calcium-like inhomogeneities within chicken tissue at 7 T with optimized MR acquisition parameters. The method was also evaluated for detection of simulated microcalcifications, modeled from biopsy samples of malignant breast cancer, inserted in silico into breast magnetic resonance imaging (MRIs) of healthy subjects at 7 T. For both assessments of calcium fragments in phantoms and biopsy-based simulated microcalcifications in breast MRIs, receiver operator characteristic curve analyses were performed to determine the cross-correlation index cutoff, for achieving optimal sensitivity and specificity, and the area under the curve (AUC), for measuring the method’s performance. Results: The method detected calcium fragments with sizes of 0.14–0.79 mm, 1 mm calcium-like deposits, and simulated microcalcifications with sizes of 0.4–1.0 mm in images with voxel sizes between (0.2 mm){sup 3} and (0.6 mm){sup 3}. In images acquired at 7 T with voxel sizes of (0.2 mm){sup 3}–(0.4 mm){sup 3}, calcium fragments (size 0.3–0.4 mm) were detected with a sensitivity, specificity, and AUC of 78%–90%, 51%–68%, and 0.77%–0.88%, respectively. In images acquired with a human 7 T scanner, acquisition times below 12

  6. Performance of the modules for layer 1 of the CMS phase 1 pixel detector upgrade

    CERN Document Server

    Meinhard, Maren Tabea; Berger, Pirmin; Starodumov, Andrey

    2017-01-01

    The instantaneous luminosity of the Large Hadron Collider will increase to up to 2x10$^{34}$\\;cm$^{-2}$s$^{-1}$ by 2023. In order to cope with such luminosities, the pixel detector of the CMS experiment has been replaced in January 2017. The upgraded detector features four sensitive layers in the barrel part. A designated readout chip (PROC600V2) is used for layer 1, which is closest to the interaction point and therefore has to handle larger particle fluxes. An irradiation campaign has been performed with PROC600V2 to verify its radiation tolerance up to the maximum expected dose for 2017 of 0.2\\;MGy. Modules for layer 1 have been built with PROC600V2 for the detector production. The quality of every inserted module was assessed in a number of tests, some of which were performed using X-radiation. The characteristics of the modules used in the detector as well as the main failure modes will be presented.

  7. High Performance ZVT with Bus Clamping Modulation Technique for Single Phase Full Bridge Inverters

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Yinglai; Ayyanar, Raja

    2016-03-20

    This paper proposes a topology based on bus clamping modulation and zero-voltage-transition (ZVT) technique to realize zero-voltage-switching (ZVS) for all the main switches of the full bridge inverters, and inherent ZVS and/or ZCS for the auxiliary switches. The advantages of the strategy include significant reduction in the turn-on loss of the ZVT auxiliary switches which typically account for a major part of the total loss in other ZVT circuits, and reduction in the voltage ratings of auxiliary switches. The modulation scheme and the commutation stages are analyzed in detail. Finally, a 1kW, 500 kHz switching frequency inverter of the proposed topology using SiC MOSFETs has been built to validate the theoretical analysis. The ZVT with bus clamping modulation technique of fixed timing and adaptive timing schemes are implemented in DSP TMS320F28335 resulting in full ZVS for the main switches in the full bridge inverter. The proposed scheme can save up to 33 % of the switching loss compared with no ZVT case.

  8. Readout architecture for the Pixel-Strip module of the CMS Outer Tracker Phase-2 upgrade

    CERN Document Server

    Caratelli, Alessandro; Jan Kaplon; Kloukinas, Konstantinos; Simone Scarfi

    2017-01-01

    The Outer Tracker upgrade of the Compact Muon Solenoid (CMS) experiment at CERN introduces new challenges for the front-end readout electronics. In particular, the capability of identifying particles with high transverse momentum using modules with double sensor layers requires high speed real time interconnects between readout ASICs. The Pixel-Strip module combines a pixelated silicon layer with a silicon-strip layer. Consequently, it needs two different readout ASICs, namely the Short Strip ASIC (SSA) for the strip sensor and the Macro Pixel ASIC (MPA) for the pixelated sensor. The architecture proposed in this paper allows for a total data flow between readout ASICs of $\\sim$100\\,Gbps and reduces the output data flow from 1.3\\,Tbps to 30\\,Gbps per module while limiting the total power density to below 100\\,mW/cm$^2$. In addition a system-level simulation framework of all the front-end readout ASICs is developed in order to verify the data processing algorithm and the hardware implementation allowing mult...

  9. Single-phase cross-mixing measurements in a 4 x 4 rod bundle

    International Nuclear Information System (INIS)

    Yloenen, Arto; Bissels, Wilhelm-Martin; Prasser, Horst-Michael

    2011-01-01

    Highlights: → The wire-mesh sensor technique has been successfully introduced into a fuel rod bundle geometry. → Quantitative information on the turbulent dispersion of the fluid was obtained. → In full spatial and temporal resolution, the data is interesting for the unsteady CFD validation. - Abstract: The wire-mesh sensor technique has been successfully introduced into a fuel rod bundle geometry for the first time. In this context, a dedicated test facility (SUBFLOW) has been designed and constructed at Paul Scherrer Institut (PSI) in a co-operation with the Swiss Federal Institute of Technology (ETH Zuerich). Two wire-mesh sensors designed and built in-house were installed in the upper part of the vertical test section of SUBFLOW, and single-phase experiments on the turbulent mass exchange between neighboring sub-channels were performed. For this purpose, salt tracer was injected locally in one of the sub-channels and conductivity distributions in the bundle measured by the wire-mesh sensor. Both flow rate and distance from the injection point were varied. The latter was achieved by using injection nozzles at different heights. In this way, the sensor located in the upper part of the channel could be used to characterize the progress of the mixing along the flow direction, and the degree of cross-mixing assessed using the quantity of tracer arriving in the neighboring sub-channels. Fluctuations of the tracer concentration in time were used for statistical evaluations, such as the calculation of standard deviations and two-point correlations.

  10. High efficiency H6 single-phase transformerless grid-tied PV inverter with proposed modulation for reactive power generation

    Science.gov (United States)

    Almasoudi, Fahad M.; Alatawi, Khaled S.; Matin, Mohammad

    2017-08-01

    Implementation of transformerless inverters in PV grid-tied system offer great benefits such as high efficiency, light weight, low cost, etc. Most of the proposed transformerless inverters in literature are verified for only real power application. Currently, international standards such as VDE-AR-N 4105 has demanded that PV grid-tied inverters should have the ability of controlling a specific amount of reactive power. Generation of reactive power cannot be accomplished in single phase transformerless inverter topologies because the existing modulation techniques are not adopted for a freewheeling path in the negative power region. This paper enhances a previous high efficiency proposed H6 trnasformerless inverter with SiC MOSFETs and demonstrates new operating modes for the generation of reactive power. A proposed pulse width modulation (PWM) technique is applied to achieve bidirectional current flow through freewheeling state. A comparison of the proposed H6 transformerless inverter using SiC MOSFETs and Si MOSFTEs is presented in terms of power losses and efficiency. The results show that reactive power control is attained without adding any additional active devices or modification to the inverter structure. Also, the proposed modulation maintains a constant common mode voltage (CM) during every operating mode and has low leakage current. The performance of the proposed system verifies its effectiveness in the next generation PV system.

  11. Nature of low dimensional structural modulations and relative phase stability in RexMo(W)1-xS2 transition metal dichalcogenide alloys

    KAUST Repository

    Sahu, R.; Bhat, U.; Batra, Nitin M; Sharona, H.; Vishal, B.; Sarkar, S.; Devi, Assa Aravindh Sasikala; Peter, S. C.; Roqan, Iman S.; Costa , P. M. F. J.; Datta, Ranjan

    2017-01-01

    We report on the various types of Peierls like two dimensional structural modulations and relative phase stability of 2H and 1T poly-types in the RexMo1-xS2 and RexW1-xS2 alloy system. Theoretical calculation predicts a polytype phase transition

  12. Characterization of Cr-rich Cr-Sb multilayer films: Syntheses of a new metastable phase using modulated elemental reactants

    International Nuclear Information System (INIS)

    Regus, Matthias; Mankovsky, Sergiy; Polesya, Svitlana; Kuhn, Gerhard; Ditto, Jeffrey; Schürmann, Ulrich; Jacquot, Alexandre; Bartholomé, Kilian; Näther, Christian; Winkler, Markus; König, Jan D.; Böttner, Harald; Kienle, Lorenz; Johnson, David C.; Ebert, Hubert; Bensch, Wolfgang

    2015-01-01

    The new metastable compound Cr 1+x Sb with x up to 0.6 has been prepared via a thin film approach using modulated elemental reactants and investigated by in-situ X-ray reflectivity, X-ray diffraction, differential scanning calorimetry, energy dispersive X-ray analysis as well as transmission electron microscopy and atomic force microscopy. The new Cr-rich antimonide crystallizes in a structure related to the Ni 2 In-type structure, where the crystallographic position (1/3, 2/3, 3/4) is partially occupied by excess Cr. The elemental layers of the pristine material interdiffused significantly before Cr 1+x Sb crystallized. A change in the activation energy was observed for the diffusion process when crystal growth starts. First-principles electronic structure calculations provide insight into the structural stability, magnetic properties and resistivity of Cr 1+x Sb. - Graphical abstract: 1 amorphous multilayered film 2 interdiffused amorphous film 3 metastable crystalline phase 4 thermodynamic stable phase (and by-product). - Highlights: • Interdiffusion of amorphous Cr and Sb occurs before crystallization. • Crystallization of a new metastable phase Cr 1.6 Sb in Ni 2 In-type structure. • The new Cr-rich phase shows half-metallic behavior

  13. Sub-threshold cross-modal sensory interaction in the thalamus: lemniscal auditory response in the medial geniculate nucleus is modulated by somatosensory stimulation.

    Science.gov (United States)

    Donishi, T; Kimura, A; Imbe, H; Yokoi, I; Kaneoke, Y

    2011-02-03

    Recent studies have highlighted cross-modal sensory modulations in the primary sensory areas in the cortex, suggesting that cross-modal sensory interactions occur at early stages in the hierarchy of sensory processing. Multi-modal sensory inputs from non-lemniscal thalamic nuclei and cortical inputs from the secondary sensory and association areas are considered responsible for the modulations. On the other hand, there is little evidence of cross-sensory modal sensitivities in lemniscal thalamic nuclei. In the present study, we were interested in a possibility that somatosensory stimulation may affect auditory response in the ventral division (MGV) of the medial geniculate nucleus (MG), a lemniscal thalamic nucleus that is considered to be dedicated to auditory uni-modal processing. Experiments were performed on anesthetized rats. Transcutaneous electrical stimulation of the hindpaw, which is thought to evoke nociception and seems unrelated to auditory processing, modulated unit discharges in response to auditory stimulation (noise bursts). The modulation was observed in the MGV and non-lemniscal auditory thalamic nuclei such as the dorsal and medial divisions of the MG. The major effect of somatosensory stimulation was suppression. The most robust suppression was induced by electrical stimuli given simultaneously with noise bursts or preceding noise bursts by 10 to 20 ms. The results indicate that the lemniscal (MGV) and non-lemniscal auditory nuclei are subject to somatosensory influence. In everyday experience intense somatosensory stimuli such as pain interrupt our ongoing hearing or interfere with clear recognition of sound. The modulation of lemniscal auditory response by somatosensory stimulation may underlie such cross-modal disturbance of auditory perception as a form of cross-modal switching of attention. Copyright © 2011 IBRO. Published by Elsevier Ltd. All rights reserved.

  14. Spectral broadening of 25 fs laser pulses via self-phase modulation in a neon filled hollow core fibre

    Energy Technology Data Exchange (ETDEWEB)

    Weichert, Stefan

    2017-05-15

    The goal of this work was the realisation of a setup for spectral broadening and subsequent compression of 25 fs laser pulses provided by a commercial Ti:Sapphire based CPA laser system by means of the hollow core fibre chirped mirror compressor technique. For the spectral broadening a vessel containing the hollow waveguide filled with a noble gas serving as the nonlinear medium was set up and an alignment procedure was developed. Neon was chosen as the nonlinear medium for the self-phase modulation of the pulses. With this setup spectral broadening, sufficient for supporting sub 5 fs pulses, was observed. The spectra at different input energies and neon gas pressures were measured and the stability of these and their respective Fourier transform-limited pulses determined in order to find an operating point. For the compression of the self-phase modulated pulses a chirped mirror compressor was designed and set up, but not tested yet. The layout of a single-shot intensity autocorrelator capable of estimating the pulse duration of sub 10 fs pulses was given.

  15. Method of optical coherence tomography with parallel depth-resolved signal reception and fibre-optic phase modulators

    Energy Technology Data Exchange (ETDEWEB)

    Morozov, A N; Turchin, I V [Institute of Applied Physics, Russian Academy of Sciences, Nizhnii Novgorod (Russian Federation)

    2013-12-31

    The method of optical coherence tomography with the scheme of parallel reception of the interference signal (P-OCT) is developed on the basis of spatial paralleling of the reference wave by means of a phase diffraction grating producing the appropriate time delay in the Mach–Zehnder interferometer. The absence of mechanical variation of the optical path difference in the interferometer essentially reduces the time required for 2D imaging of the object internal structure, as compared to the classical OCT that uses the time-domain method of the image construction, the sensitivity and the dynamic range being comparable in both approaches. For the resulting field of the interfering object and reference waves an analytical expression is derived that allows the calculation of the autocorrelation function in the plane of photodetectors. For the first time a method of linear phase modulation by 2π is proposed for P-OCT systems, which allows the use of compact high-frequency (a few hundred kHz) piezoelectric cell-based modulators. For the demonstration of the P-OCT method an experimental setup was created, using which the images of the inner structure of biological objects at the depth up to 1 mm with the axial spatial resolution of 12 μm were obtained. (optical coherence tomography)

  16. Spectral broadening of 25 fs laser pulses via self-phase modulation in a neon filled hollow core fibre

    International Nuclear Information System (INIS)

    Weichert, Stefan

    2017-05-01

    The goal of this work was the realisation of a setup for spectral broadening and subsequent compression of 25 fs laser pulses provided by a commercial Ti:Sapphire based CPA laser system by means of the hollow core fibre chirped mirror compressor technique. For the spectral broadening a vessel containing the hollow waveguide filled with a noble gas serving as the nonlinear medium was set up and an alignment procedure was developed. Neon was chosen as the nonlinear medium for the self-phase modulation of the pulses. With this setup spectral broadening, sufficient for supporting sub 5 fs pulses, was observed. The spectra at different input energies and neon gas pressures were measured and the stability of these and their respective Fourier transform-limited pulses determined in order to find an operating point. For the compression of the self-phase modulated pulses a chirped mirror compressor was designed and set up, but not tested yet. The layout of a single-shot intensity autocorrelator capable of estimating the pulse duration of sub 10 fs pulses was given.

  17. Schedule-selective biochemical modulation of 5-fluorouracil in advanced colorectal cancer – a phase II study

    Directory of Open Access Journals (Sweden)

    Savage Paul

    2002-05-01

    Full Text Available Abstract Background 5-fluorouracil remains the standard therapy for patients with advanced/metastatic colorectal cancer. Pre-clinical studies have demonstrated the biological modulation of 5-fluorouracil by methotrexate and leucovorin. This phase II study was initiated to determine the activity and toxicity of sequential methotrexate – leucovorin and 5-fluorouracil chemotherapy in patients with advanced colorectal cancer. Methods Ninety-seven patients with metastatic colorectal cancer were enrolled onto the study. Methotrexate – 30 mg/m2 was administered every 6 hours for 6 doses followed by a 2 hour infusion of LV – 500 mg/m2. Midway through the leucovorin infusion, patients received 5-fluorouracil – 600 mg/m2. This constituted a cycle of therapy and was repeated every 2 weeks until progression. Results The median age was 64 yrs (34–84 and the Eastern Cooperative Group Oncology performance score was 0 in 37%, 1 in 55% and 2 in 8% of patients. Partial and complete responses were seen in 31% of patients with a median duration of response of 6.4 months. The overall median survival was 13.0 months. The estimated 1-year survival was 53.7%. Grade III and IV toxic effects were modest and included mucositis, nausea and vomiting. Conclusions This phase II study supports previously reported data demonstrating the modest clinical benefit of 5-FU modulation utilizing methotrexate and leucovorin in patients with metastatic colorectal cancer. Ongoing studies evaluating 5-fluorouracil modulation with more novel agents (Irinotecan and/or oxaliplatin are in progress and may prove encouraging.

  18. Experimental 2.5-Gb/s QPSK WDM phase-modulated radio-over-fiber link with digital demodulation by a K-means algorithm

    DEFF Research Database (Denmark)

    Guerrero Gonzalez, Neil; Zibar, Darko; Caballero Jambrina, Antonio

    2010-01-01

    Highest reported bit rate of 2.5 Gb/s for optically phase modulated radio-over-fiber (RoF) link, employing digital coherent detection, is demonstrated. Demodulation of 3$,times,$ 2.5 Gb/s quadrature phase-shift keying modulated wavelength-division-multiplexed RoF channels is achieved after 79 km ...... of transmission through deployed fiber. Error-free performance (bit-error rate corresponding to $10^{{-}4}$) is achieved using a digital coherent receiver in combination with a $K$-means algorithm for radio-frequency phase recovery....

  19. Non-binary Colour Modulation for Display Device Based on Phase Change Materials

    Science.gov (United States)

    Ji, Hong-Kai; Tong, Hao; Qian, Hang; Hui, Ya-Juan; Liu, Nian; Yan, Peng; Miao, Xiang-Shui

    2016-12-01

    A reflective-type display device based on phase change materials is attractive because of its ultrafast response time and high resolution compared with a conventional display device. This paper proposes and demonstrates a unique display device in which multicolour changing can be achieved on a single device by the selective crystallization of double layer phase change materials. The optical contrast is optimized by the availability of a variety of film thicknesses of two phase change layers. The device exhibits a low sensitivity to the angle of incidence, which is important for display and colour consistency. The non-binary colour rendering on a single device is demonstrated for the first time using optical excitation. The device shows the potential for ultrafast display applications.

  20. Simulating the control of molecular reactions via modulated light fields: from gas phase to solution

    Science.gov (United States)

    Thallmair, Sebastian; Keefer, Daniel; Rott, Florian; de Vivie-Riedle, Regina

    2017-04-01

    Over the past few years quantum control has proven to be very successful in steering molecular processes. By combining theory with experiment, even highly complex control aims were realized in the gas phase. In this topical review, we illustrate the past achievements on several examples in the molecular context. The next step for the quantum control of chemical processes is to translate the fruitful interplay between theory and experiment to the condensed phase and thus to the regime where chemical synthesis can be supported. On the theory side, increased efforts to include solvent effects in quantum control simulations were made recently. We discuss two major concepts, namely an implicit description of the environment via the density matrix algorithm and an explicit inclusion of solvent molecules. By application to chemical reactions, both concepts conclude that despite environmental perturbations leading to more complex control tasks, efficient quantum control in the condensed phase is still feasible.

  1. Non-binary Colour Modulation for Display Device Based on Phase Change Materials.

    Science.gov (United States)

    Ji, Hong-Kai; Tong, Hao; Qian, Hang; Hui, Ya-Juan; Liu, Nian; Yan, Peng; Miao, Xiang-Shui

    2016-12-19

    A reflective-type display device based on phase change materials is attractive because of its ultrafast response time and high resolution compared with a conventional display device. This paper proposes and demonstrates a unique display device in which multicolour changing can be achieved on a single device by the selective crystallization of double layer phase change materials. The optical contrast is optimized by the availability of a variety of film thicknesses of two phase change layers. The device exhibits a low sensitivity to the angle of incidence, which is important for display and colour consistency. The non-binary colour rendering on a single device is demonstrated for the first time using optical excitation. The device shows the potential for ultrafast display applications.

  2. New catenated OFDM modulation scheme in zero cross correlation OCDMA at various number of user and effective power

    Directory of Open Access Journals (Sweden)

    Nawawi N. M.

    2017-01-01

    Full Text Available This paper proposes an integration of optical Code Division Multiple Access (OCDMA with new catenated Orthogonal Frequency Division Multiplexing (OFDM modulation scheme. This effective combination based on Zero Cross Correlation (ZCC code can enhanced the system capacity and increased spectral efficiency by fully utilizing the available electrical bandwidth. We investigate the performance of the proposed system for various number of user, number of weight and effective power. The performance assessment is carried out by means of the signal to noise ratio (SNR and bit error rate (BER for up to five catenated OFDM bands transmitted simultaneously through optical link at 622 Mbps. More specifically, mathematical expressions for SNR and BER performance are derived. The corresponding numerical results are presented and compared with traditional OCDMA-ZCC system to verified the feasibility of the proposed system. The results show that with OCDMA/catenated-OFDM based on ZCC code provides 86% more number of permissible user for SNR of 15 dB. In addition, this integration provides higher receiver sensitivity; an approximately –22.5 dBm for 20 number of user with 8 number of weight. It is also found that, to accommodate more user, the system requires higher effective power at the receiver.

  3. Optical implementation of neural learning algorithms based on cross-gain modulation in a semiconductor optical amplifier

    Science.gov (United States)

    Li, Qiang; Wang, Zhi; Le, Yansi; Sun, Chonghui; Song, Xiaojia; Wu, Chongqing

    2016-10-01

    Neuromorphic engineering has a wide range of applications in the fields of machine learning, pattern recognition, adaptive control, etc. Photonics, characterized by its high speed, wide bandwidth, low power consumption and massive parallelism, is an ideal way to realize ultrafast spiking neural networks (SNNs). Synaptic plasticity is believed to be critical for learning, memory and development in neural circuits. Experimental results have shown that changes of synapse are highly dependent on the relative timing of pre- and postsynaptic spikes. Synaptic plasticity in which presynaptic spikes preceding postsynaptic spikes results in strengthening, while the opposite timing results in weakening is called antisymmetric spike-timing-dependent plasticity (STDP) learning rule. And synaptic plasticity has the opposite effect under the same conditions is called antisymmetric anti-STDP learning rule. We proposed and experimentally demonstrated an optical implementation of neural learning algorithms, which can achieve both of antisymmetric STDP and anti-STDP learning rule, based on the cross-gain modulation (XGM) within a single semiconductor optical amplifier (SOA). The weight and height of the potentitation and depression window can be controlled by adjusting the injection current of the SOA, to mimic the biological antisymmetric STDP and anti-STDP learning rule more realistically. As the injection current increases, the width of depression and potentitation window decreases and height increases, due to the decreasing of recovery time and increasing of gain under a stronger injection current. Based on the demonstrated optical STDP circuit, ultrafast learning in optical SNNs can be realized.

  4. Candida albicans mannans mediate Streptococcus mutans exoenzyme GtfB binding to modulate cross-kingdom biofilm development in vivo.

    Science.gov (United States)

    Hwang, Geelsu; Liu, Yuan; Kim, Dongyeop; Li, Yong; Krysan, Damian J; Koo, Hyun

    2017-06-01

    Candida albicans is frequently detected with heavy infection by Streptococcus mutans in plaque-biofilms from children with early-childhood caries (ECC). This cross-kingdom biofilm contains an extensive matrix of extracellular α-glucans that is produced by an exoenzyme (GtfB) secreted by S. mutans. Here, we report that mannans located on the outer surface of C. albicans cell-wall mediates GtfB binding, enhancing glucan-matrix production and modulating bacterial-fungal association within biofilms formed in vivo. Using single-molecule atomic force microscopy, we determined that GtfB binds with remarkable affinity to mannans and to the C. albicans surface, forming a highly stable and strong bond (1-2 nN). However, GtfB binding properties to C. albicans was compromised in strains defective in O-mannan (pmt4ΔΔ) or N-mannan outer chain (och1ΔΔ). In particular, the binding strength of GtfB on och1ΔΔ strain was severely disrupted (>3-fold reduction vs. parental strain). In turn, the GtfB amount on the fungal surface was significantly reduced, and the ability of C. albicans mutant strains to develop mixed-species biofilms with S. mutans was impaired. This phenotype was independent of hyphae or established fungal-biofilm regulators (EFG1, BCR1). Notably, the mechanical stability of the defective biofilms was weakened, resulting in near complete biomass removal by shear forces. In addition, these in vitro findings were confirmed in vivo using a rodent biofilm model. Specifically, we observed that C. albicans och1ΔΔ was unable to form cross-kingdom biofilms on the tooth surface of rats co-infected with S. mutans. Likewise, co-infection with S. mutans defective in GtfB was also incapable of forming mixed-species biofilms. Taken together, the data support a mechanism whereby S. mutans-secreted GtfB binds to the mannan layer of C. albicans to promote extracellular matrix formation and their co-existence within biofilms. Enhanced understanding of GtfB-Candida interactions

  5. Linearized Optically Phase-Modulated Fiber Optic Links for Microwave Signal Transport

    Science.gov (United States)

    2009-03-03

    detectors (with internal 50- Ohm resistors) capable of 40-mA dc current per detector. With this link, the linearized SFDR would improve to 133 dB/Hz4/5...the IF) limitation on the signal. All calculations consider the 3dB power loss from the hybrid combiner and 6dB loss from parallel 50- Ohm resistors...283. [25] M. Nazarathy, J. Berger, A. Ley , I. Levi, and Y. Kagan, “Externally Modulated 80 Channel Am Catv Fiber-to-feeder Distribution System Over

  6. Acoustic analog computing based on a reflective metasurface with decoupled modulation of phase and amplitude

    Science.gov (United States)

    Zuo, Shu-Yu; Tian, Ye; Wei, Qi; Cheng, Ying; Liu, Xiao-Jun

    2018-03-01

    The use of metasurfaces has allowed the provision of a variety of functionalities by ultrathin structures, paving the way toward novel highly compact analog computing devices. Here, we conceptually realize analog computing using an acoustic reflective computational metasurface (RCM) that can independently manipulate the reflection phase and amplitude of an incident acoustic signal. This RCM is composed of coating unit cells and perforated panels, where the first can tune the transmission phase within the full range of 2π and the second can adjust the reflection amplitude in the range of 0-1. We show that this RCM can achieve arbitrary reflection phase and amplitude and can be used to realize a unique linear spatially invariant transfer function. Using the spatial Fourier transform (FT), an acoustic analog computing (AAC) system is proposed based on the RCM together with a focusing lens. Based on numerical simulations, we demonstrate that this AAC system can perform mathematical operations such as spatial differentiation, integration, and convolution on an incident acoustic signal. The proposed system has low complexity and reduced size because the RCM is able to individually adjust the reflection phase and amplitude and because only one block is involved in performing the spatial FT. Our work may offer a practical, efficient, and flexible approach to the design of compact devices for acoustic computing applications, signal processing, equation solving, and acoustic wave manipulations.

  7. Modulation of the acute phase response in feedlot steers supplemented with Saccharomyces cerevisiae

    Science.gov (United States)

    This study was designed to determine the effect of supplementing feedlot steers with Saccharomyces cerevisiae CNCM I-1079 (SC) on the acute phase response to a lipopolysaccharide (LPS) challenge. Steers (n = 18; 266 ± 4 kilograms body weight) were separated into three treatment groups (n = 6/treatm...

  8. A Smart Current Modulation Scheme for Harmonic Reduction in Three- Phase Motor Drive Applications

    DEFF Research Database (Denmark)

    Davari, Pooya; Zare, Firuz; Blaabjerg, Frede

    2015-01-01

    Electric motor-driven systems consume considerable amount of the global electricity. Majority of three-phase motor drives are equipped with conventional diode rectifier and passive harmonic mitigation, being witnessed as the main source in generating input current harmonics. While many active har...

  9. Dynamics of self-focusing and self-phase modulation of elliptic ...

    Indian Academy of Sciences (India)

    Using a direct variational technique involving elliptic Gaussian laser beam trial function, the combined effect of non-linearity and diffraction on wave propagation of optical beam in a homogeneous bulk Kerr-medium is presented. Particular emphasis is put on the variation of beam width and longitudinal phase delay with the ...

  10. A Multipulse Pattern Modulation Scheme for Harmonic Mitigation in Three-Phase Multimotor Drives

    DEFF Research Database (Denmark)

    Davari, Pooya; Yang, Yongheng; Zare, Firuz

    2016-01-01

    , which thus deteriorates the power grid quality and also lowers the conversion efficiency. Both degradations are apt to occur in motor drive applications. At present, many industrial drives are equipped with three-phase diode rectifiers and employ passive filtering techniques on the AC or DC side...

  11. Optical modulation in nematic phase of halogen substituted hydrogen bonded liquid crystals

    Science.gov (United States)

    Vijayakumar, V. N.; Madhu Mohan, M. L. N.

    2012-01-01

    A series of halogen-substituted hydrogen-bonded liquid crystalline complexes have been designed and synthesised. A successful attempt has been made to form complementary hydrogen bonding between the dodecyloxy benzoic acid (12BAO) and halogen-substituted benzoic acids and the physical properties exhibited by the individual complexes are studied. The complexes obtained are analysed by polarising optical microscope (POM), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and dielectric studies. The formation of complementary hydrogen bond is confirmed through FTIR spectra. An interesting feature of this series is the observation of a field-induced transition (FiT) in nematic phase. Another interesting phenomenon is the observation of a new smectic X phase (worm-like texture) in all the synthesised complexes. Dielectric relaxation studies in the smectic C phase of these hydrogen bonded complexes along with the Arrhenius and the Cole-Cole plots are discussed. Optical tilt angle in smectic C phase and the corresponding fitted data analysis concur with the Mean field theory prediction.

  12. Non-Interferometric Tomography of Phase Objects Using Spatial Light Modulators

    Directory of Open Access Journals (Sweden)

    Thanh Nguyen

    2016-10-01

    Full Text Available Quantitative 3D phase retrieval techniques are based on either interferometric techniques such as holography or noninterferometric intensity-based techniques such as the transport of intensity equation (TIE. Interferometric techniques are vibration-sensitive and often use a reference beam requiring complicated optical alignment. In this work we develop a simple, fast, and noninterferometric tomographic 3D phase retrieval technique based on the TIE which does not suffer from such drawbacks. The optical setup is a modified 4f TIE system which uses an SLM to replace the slow translation of the CCD required to record several diffraction patterns in a traditional TIE system. This novel TIE setup is suitable for dynamical events such as imaging biological processes. A rotating mechanical stage is constructed to obtain tomographic phase images of the object. The tomographic reconstruction algorithm is based on the Fourier slice theorem (backprojection algorithm which applies to objects with a small refractive index span. Simulation and experimental results are shown as part of this work. A graphical user interface is developed to perform the TIE tomographic reconstruction algorithm and to synchronize the captured intensities by the CCD, the phase patterns displayed on the SLM, and the Arduino controlled rotating stage assembly.

  13. Testbeam evaluation of silicon strip modules for ATLAS Phase - II Strip Tracker Upgrade

    CERN Document Server

    Blue, Andrew; The ATLAS collaboration; Ai, Xiaocong; Allport, Phillip; Arling, Jan-Hendrik; Atkin, Ryan Justin; Bruni, Lucrezia Stella; Carli, Ina; Casse, Gianluigi; Chen, Liejian; Chisholm, Andrew; Cormier, Kyle James Read; Cunningham, William Reilly; Dervan, Paul; Diez Cornell, Sergio; Dolezal, Zdenek; Dopke, Jens; Dreyer, Etienne; Dreyling-Eschweiler, Jan Linus Roderik; Escobar, Carlos; Fabiani, Veronica; Fadeyev, Vitaliy; Fernandez Tejero, Javier; Fleta Corral, Maria Celeste; Gallop, Bruce; Garcia-Argos, Carlos; Greenall, Ashley; Gregor, Ingrid-Maria; Greig, Graham George; Guescini, Francesco; Hara, Kazuhiko; Hauser, Marc Manuel; Huang, Yanping; Hunter, Robert Francis Holub; Keller, John; Klein, Christoph; Kodys, Peter; Koffas, Thomas; Kotek, Zdenek; Kroll, Jiri; Kuehn, Susanne; Lee, Steven Juhyung; Liu, Yi; Lohwasser, Kristin; Meszarosova, Lucia; Mikestikova, Marcela; Mi\\~nano Moya, Mercedes; Mori, Riccardo; Moser, Brian; Nikolopoulos, Konstantinos; Peschke, Richard; Pezzullo, Giuseppe; Phillips, Peter William; Poley, Anne-luise; Queitsch-Maitland, Michaela; Ravotti, Federico; Rodriguez Rodriguez, Daniel

    2018-01-01

    The planned HL-LHC (High Luminosity LHC) is being designed to maximise the physics potential of the LHC with 10 years of operation at instantaneous luminosities of \\mbox{$7.5\\times10^{34}\\;\\mathrm{cm}^{-2}\\mathrm{s}^{-1}$}. A consequence of this increased luminosity is the expected radiation damage requiring the tracking detectors to withstand hadron equivalences to over $1x10^{15}$ 1 MeV neutron equivalent per $cm^{2}$ in the ATLAS Strips system. The silicon strip tracker exploits the concept of modularity. Fast readout electronics, deploying 130nm CMOS front-end electronics are glued on top of a silicon sensor to make a module. The radiation hard n-in-p micro-strip sensors used have been developed by the ATLAS ITk Strip Sensor collaboration and produced by Hamamatsu Photonics. A series of tests were performed at the DESY-II test beam facility to investigate the detailed performance of a strip module with both 2.5cm and 5cm length strips before irradiation. The DURANTA telescope was used to obtain a pointing...

  14. Frequency modulation reveals the phasing of orbital eccentricity during Cretaceous Oceanic Anoxic Event II and the Eocene hyperthermals

    Science.gov (United States)

    Laurin, Jiří; Meyers, Stephen R.; Galeotti, Simone; Lanci, Luca

    2016-05-01

    Major advances in our understanding of paleoclimate change derive from a precise reconstruction of the periods, amplitudes and phases of the 'Milankovitch cycles' of precession, obliquity and eccentricity. While numerous quantitative approaches exist for the identification of these astronomical cycles in stratigraphic data, limitations in radioisotopic dating, and instability of the theoretical astronomical solutions beyond ∼50 Myr ago, can challenge identification of the phase relationships needed to constrain climate response and anchor floating astrochronologies. Here we demonstrate that interference patterns accompanying frequency modulation (FM) of short eccentricity provide a robust basis for identifying the phase of long eccentricity forcing in stratigraphic data. One- and two-dimensional models of sedimentary distortion of the astronomical signal are used to evaluate the veracity of the FM method, and indicate that pristine eccentricity FM can be readily distinguished in paleo-records. Apart from paleoclimatic implications, the FM approach provides a quantitative technique for testing and calibrating theoretical astronomical solutions, and for refining chronologies for the deep past. We present two case studies that use the FM approach to evaluate major carbon-cycle perturbations of the Eocene and Late Cretaceous. Interference patterns in the short-eccentricity band reveal that Eocene hyperthermals ETM2 ('Elmo'), H2, I1 and ETM3 (X; ∼52-54 Myr ago) were associated with maxima in the 405-kyr cycle of orbital eccentricity. The same eccentricity configuration favored regional anoxic episodes in the Mediterranean during the Middle and Late Cenomanian (∼94.5-97 Myr ago). The initial phase of the global Oceanic Anoxic Event II (OAE II; ∼93.9-94.5 Myr ago) coincides with maximum and falling 405-kyr eccentricity, and the recovery phase occurs during minimum and rising 405-kyr eccentricity. On a Myr scale, the event overlaps with a node in eccentricity

  15. Stationary-phase integrals in the cross correlation of ambient noise

    NARCIS (Netherlands)

    Boschi, L.; Weemstra, C.

    2015-01-01

    The cross correlation of ambient signal allows seismologists to collect data even in the absence of seismic events. “Seismic interferometry” shows that the cross correlation of simultaneous recordings of a random wavefield made at two locations is formally related to the impulse response between

  16. Plastic Change along the Intact Crossed Pathway in Acute Phase of Cerebral Ischemia Revealed by Optical Intrinsic Signal Imaging

    Directory of Open Access Journals (Sweden)

    Xiaoli Guo

    2016-01-01

    Full Text Available The intact crossed pathway via which the contralesional hemisphere responds to the ipsilesional somatosensory input has shown to be affected by unilateral stroke. The aim of this study was to investigate the plasticity of the intact crossed pathway in response to different intensities of stimulation in a rodent photothrombotic stroke model. Using optical intrinsic signal imaging, an overall increase of the contralesional cortical response was observed in the acute phase (≤48 hours after stroke. In particular, the contralesional hyperactivation is more prominent under weak stimulations, while a strong stimulation would even elicit a depressed response. The results suggest a distinct stimulation-response pattern along the intact crossed pathway after stroke. We speculate that the contralesional hyperactivation under weak stimulations was due to the reorganization for compensatory response to the weak ipsilateral somatosensory input.

  17. Characterization of the phase transformations in shape-memory alloys by modulated differential scanning calorimetry

    International Nuclear Information System (INIS)

    Wei, Z.G.; Sandstroem, R.

    1999-01-01

    Modulated differential scanning calorimetry (MDSC) is a recently developed calorimetric technique, which has demonstrated some significant advantages over the conventional differential scanning calorimetry (DSC). By separating the reversing quantity from the non-reversing component in the total thermal events, it provides some new information that can not be obtained from the conventional DSC. The technique has been applied to various polycrystalline and single crystalline shape-memory alloys, including Cu-Zn-Al, Cu-Al-Ni, Ti-Ni(Cu), Ni-Mn-Ga and Fe-Mn-Si, to characterize the martensitic transformations, bainitic transformation, chemical and magnetic ordering transitions, atomic reordering and other kinetic relaxation processes in the alloys. The preliminary results of the MDSC measurements are summarized and the interpretation of the MDSC results and some factors affecting the results are discussed. (orig.)

  18. Preliminary results of phase I/II study of simultaneous modulated accelerated (SMART) for nasopharyngeal carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jin Hong; Lee, Sang Wook; Back, Geum Mun [College of Medicine, University of Ulsan, Asan Medical Center, Seoul (Korea, Republic of)] (and others)

    2006-03-15

    To present preliminary results of intensity-modulated radiotherapy (IMRT) using the simultaneous modulated accelerated radiation therapy (SMART) boost technique in patients with nasopharyngeal carcinoma (NPC). Twenty patients who underwent IMRT for non-metastatic NPC at the Asan Medical Center between September 2001 and December 2003 were prospectively evaluated. IMRT was delivered using the 'step and shoot' SMART technique at prescribed doses of 72 Gy (2.4 Gy/day) to the gross tumor volume (GTV), 60 Gy (2 Gy/day) to the clinical target volume (CTV) and metastatic nodal station, and 46 Gy (2 Gy/day) to the clinically negative neck region. Eighteen patients also received concurrent chemotherapy using cisplatin once per week. The median follow-up period was 27 months. Nineteen patients completed the treatment without interruption; the remaining patient interrupted treatment for 2 weeks owing to severe pharyngitis and malnutrition. Five patients (25%) had RTOG grade 3 mucositis, whereas nine (45%) had grade 3 pharyngitis. Seven patients (35%) lost more than 10% of their pretreatment weight, whereas 11 (55%) required intravenous fluids and/or tube feeding. There was no grade 3 or 4 chronic xerostomia. All patients showed complete response. Two patients had distant metastases and loco-regional recurrence, respectively. IMRT using the SMART boost technique allows parotid sparing, as shown clinically and by dosimetry, and may also be more effective biologically. A larger population of patients and a longer follow-up period are needed to evaluate ultimate tumor control and late toxicity.

  19. Agmatine Modulates the Phenotype of Macrophage Acute Phase after Spinal Cord Injury in Rats.

    Science.gov (United States)

    Kim, Jae Hwan; Kim, Jae Young; Mun, Chin Hee; Suh, Minah; Lee, Jong Eun

    2017-10-01

    Agmatine is a decarboxylated arginine by arginine decarboxylase. Agmatine is known to be a neuroprotective agent. It has been reported that agmatine works as a NMDA receptor blocker or a competitive nitric oxide synthase inhibitor in CNS injuries. In spinal cord injury, agmatine showed reduction of neuropathic pain, improvement of locomotor function, and neuroprotection. Macrophage is a key cellular component in neuroinflammation, a major cause of impairment after spinal cord injury. Macrophage has subtypes, M1 and M2 macrophages. M1 macrophage induces a pro-inflammatory response, but M2 inspires an anti-inflammatory response. In this study, it was clarified whether the neuroprotective effect of agmatine is related with the modulation of macrophage subdivision after spinal cord injury. Spinal cord injury was induced in rats with contusion using MASCIS. Animals received agmatine (100 mg/kg, IP) daily for 6 days beginning the day after spinal cord injury. The proportion of M1 and M2 macrophages are confirmed with immunohistochemistry and FACS. CD206 + & ED1 + cells were counted as M2 macrophages. The systemic treatment of agmatine increased M2 macrophages caudal side to epicenter 1 week after spinal cord injury in immunohistochemistry. M2 macrophage related markers, Arginase-1 and CD206 mRNA, were increased in the agmatine treatment group and M2 macrophage expressing and stimulated cytokine, IL-10 mRNA, also was significantly overexpressed by agmatine injection. Among BMPs, BMP2/4/7, agmatine significantly increased only the expression of BMP2 known to reduce M1 macrophage under inflammatory status. These results suggest that agmatine reduces impairment after spinal cord injury through modulating the macrophage phenotype.

  20. Early cytokine modulation after the rapid induction phase of sublingual immunotherapy with mite monomeric allergoids.

    Science.gov (United States)

    Di Gioacchino, M; Perrone, A; Petrarca, C; Di Claudio, F; Mistrello, G; Falagiani, P; Dadorante, V; Verna, N; Braga, M; Ballone, E; Cavallucci, E

    2008-01-01

    The influence of different treatment schedules of sublingual immunotherapy (SLIT) in activating IL-10-producing T-cells, crucial in inducing allergen-specific tolerance, is not completely understood. The present work was designed to evaluate allergen driven interleukin release by mononuclear cells in the early phase of SLIT, after application of different induction schemes. Twenty mite-allergic patients were enrolled, 10 (group A) treated with a traditional 98 day induction scheme and 10 (group B) with a 16 day scheme with monomeric allergoid vaccine. At the end of the induction phase, the cumulative doses taken by group A and group B patients were equivalent to 50.5 and 50.3 microg of mite group 1 allergens, respectively. The release of Th1-, Th2- and Treg-related interleukins was assessed in culture supernatants of 5 microg/ml Der-p1-stimulated mononuclear cells, isolated before and after the induction phases. No relevant treatment-related side effects were observed. Interleukin release was similar in the two groups at the enrolment. Non-stimulated and Der p 1 stimulated release of studied cytokines was similar in the two groups at enrolment. Der p 1 stimulation significantly increased IL-10 release (pallergoids are utilized.

  1. Determination of the element-specific complex permittivity using a soft x-ray phase modulator

    Science.gov (United States)

    Kubota, Y.; Hirata, Y.; Miyawaki, J.; Yamamoto, S.; Akai, H.; Hobara, R.; Yamamoto, Sh.; Yamamoto, K.; Someya, T.; Takubo, K.; Yokoyama, Y.; Araki, M.; Taguchi, M.; Harada, Y.; Wadati, H.; Tsunoda, M.; Kinjo, R.; Kagamihata, A.; Seike, T.; Takeuchi, M.; Tanaka, T.; Shin, S.; Matsuda, I.

    2017-12-01

    We report on directly determining the complex permittivity tensor using a method combining a developed light source from a segmented cross undulator of synchrotron radiation and the magneto-optical Kerr effect. The empirical permittivity, which carries the electronic and magnetic information of a material, has element specificity and has perfect confirmation using the quantum-mechanical calculation for itinerant electrons systems. These results help in understanding the interaction of light and matter, and they provide an interesting approach to seek the best materials as optical elements, for example, in extended-ultraviolet lithographic technologies or in state-of-the-art laser technologies.

  2. Two-phase flow and cross-mixing measurements in a rod bundle

    International Nuclear Information System (INIS)

    Yloenen, A.; Prasser, H.-M.

    2011-01-01

    The wire-mesh sensor technique has been used for the first time to study two-phase flow and liquid mixing in a rod bundle. A dedicated test facility (SUBFLOW) was constructed at Paul Scherrer Institut (PSI) in a co-operation with the Swiss Federal Institute of Technology (ETH Zurich). Simultaneous injection of salt water as tracer and air bubbles can be used to quantify the enhancement of liquid mixing in two-phase flow when the results are compared with the single-phase mixing experiment with the same test parameters. The second aspect in the current experiments is the two-phase flow in bundle geometry. (author)

  3. Mission profile based multi-disciplinary analysis of power modules in single-phase transformerless photovoltaic inverters

    DEFF Research Database (Denmark)

    Yang, Yongheng; Wang, Huai; Blaabjerg, Frede

    2013-01-01

    years) has been set as a main target and an emerging demand from the customers, which imposes a new challenge on grid-connected transformerless inverters. In order to reduce maintenance cost, it is essential to predict the lifetime of the transformerless PV inverter and its components based......The popularity of transformerless photovoltaic (PV) inverters in Europe proves that these topologies can achieve higher efficiency (e.g., ≥ 98% has been reported). Along with the advanced power electronics technology and the booming development of PV power systems, a long service time (e.g. 25...... on the mission profiles — solar irradiance and ambient temperature. In this paper, a mission profile based analysis approach is proposed and it is demonstrated by three main single-phase transformerless PV inverters — Full-Bridge (FB) with bipolar modulation scheme, the FB inverter with DC bypass (FB...

  4. High-efficiency and flexible generation of vector vortex optical fields by a reflective phase-only spatial light modulator.

    Science.gov (United States)

    Cai, Meng-Qiang; Wang, Zhou-Xiang; Liang, Juan; Wang, Yan-Kun; Gao, Xu-Zhen; Li, Yongnan; Tu, Chenghou; Wang, Hui-Tian

    2017-08-01

    The scheme for generating vector optical fields should have not only high efficiency but also flexibility for satisfying the requirements of various applications. However, in general, high efficiency and flexibility are not compatible. Here we present and experimentally demonstrate a solution to directly, flexibly, and efficiently generate vector vortex optical fields (VVOFs) with a reflective phase-only liquid crystal spatial light modulator (LC-SLM) based on optical birefringence of liquid crystal molecules. To generate the VVOFs, this approach needs in principle only a half-wave plate, an LC-SLM, and a quarter-wave plate. This approach has some advantages, including a simple experimental setup, good flexibility, and high efficiency, making the approach very promising in some applications when higher power is need. This approach has a generation efficiency of 44.0%, which is much higher than the 1.1% of the common path interferometric approach.

  5. Electronic origin of spatial self-phase modulation: Evidenced by comparing graphite with C{sub 60} and graphene

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Y. L.; Zhu, L. L. [College of Electronic Information and Optical Engineering, Nankai University, Tianjin 300071 (China); Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Wu, Q.; Sun, F.; Wei, J. K.; Tian, Y. C.; Wang, W. L.; Bai, X. D.; Zhao, Jimin, E-mail: jmzhao@iphy.ac.cn, E-mail: xzuonku@outlook.com [Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Zuo, Xu, E-mail: jmzhao@iphy.ac.cn, E-mail: xzuonku@outlook.com [College of Electronic Information and Optical Engineering, Nankai University, Tianjin 300071 (China)

    2016-06-13

    We report unambiguous observation of spatial self-phase modulation (SSPM) in a dispersive suspension of graphite flakes. This coherent nonlinear optical effect in bulk graphite is found to be broadband and large, with a third-order nonlinear susceptibility χ{sup (3)} of 2.2 × 10{sup −9} esu (i.e., 3.1 × 10{sup −17} m{sup 2}/V{sup 2} in SI units) at 532 nm excitation. Comparison with other carbon allotropes shows that this value is 5 × 10{sup 7} times higher than that of C{sub 60} but ∼50 times lower than that of graphene, fully exhibiting the electronic origin of SSPM.

  6. High-speed photonically assisted analog-to-digital conversion using a continuous wave multiwavelength source and phase modulation.

    Science.gov (United States)

    Bortnik, Bartosz J; Fetterman, Harold R

    2008-10-01

    A more simple photonically assisted analog-to-digital conversion system utilizing a cw multiwavelength source and phase modulation instead of a mode-locked laser is presented. The output of the cw multiwavelength source is launched into a dispersive device (such as a single-mode fiber). This fiber creates a pulse train, where the central wavelength of each pulse corresponds to a spectral line of the optical source. The pulses can then be either dispersed again to perform discrete wavelength time stretching or demultiplexed for continuous time analog-to-digital conversion. We experimentally demonstrate the operation of both time stretched and interleaved systems at 38 GHz. The potential of integrating this type of system on a monolithic chip is discussed.

  7. Functional tests of 2S modules for the CMS Phase-2 Tracker Upgrade with a MicroTCA-based readout system

    CERN Document Server

    Preuten, Marius; Klein, Katja; Lipinski, Martin; Rauch, Max; Feld, Lutz

    2017-01-01

    First full size 2S module prototypes for the CMS Phase-2 Outer Tracker Upgrade have been assembled. With two sensors of realistic dimensions and 16 CBC2 readout ASICs on two front-end hybrids, the characteristics of these novel and complex objects can be studied.A MicroTCA based readout system was developed to test multiple front-end hybrids simultaneously. Therefore the concurrent information of the full module can be used for noise and signal studies.

  8. Database of Nucleon-Nucleon Scattering Cross Sections by Stochastic Simulation, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — A database of nucleon-nucleon elastic differential and total cross sections will be generated by stochastic simulation of the quantum Liouville equation in the...

  9. Experimental Investigation on Thermal Management of Electric Vehicle Battery Module with Paraffin/Expanded Graphite Composite Phase Change Material

    Directory of Open Access Journals (Sweden)

    Jiangyun Zhang

    2017-01-01

    Full Text Available The temperature has to be controlled adequately to maintain the electric vehicles (EVs within a safety range. Using paraffin as the heat dissipation source to control the temperature rise is developed. And the expanded graphite (EG is applied to improve the thermal conductivity. In this study, the paraffin and EG composite phase change material (PCM was prepared and characterized. And then, the composite PCM have been applied in the 42110 LiFePO4 battery module (48 V/10 Ah for experimental research. Different discharge rate and pulse experiments were carried out at various working conditions, including room temperature (25°C, high temperature (35°C, and low temperature (−20°C. Furthermore, in order to obtain the practical loading test data, a battery pack with the similar specifications by 2S∗2P with PCM-based modules were installed in the EVs for various practical road experiments including the flat ground, 5°, 10°, and 20° slope. Testing results indicated that the PCM cooling system can control the peak temperature under 42°C and balance the maximum temperature difference within 5°C. Even in extreme high-discharge pulse current process, peak temperature can be controlled within 50°C. The aforementioned results exhibit that PCM cooling in battery thermal management has promising advantages over traditional air cooling.

  10. Noninvasive focused ultrasound stimulation can modulate phase-amplitude coupling between neuronal oscillations in the rat hippocampus

    Directory of Open Access Journals (Sweden)

    Yi Yuan

    2016-07-01

    Full Text Available Noninvasive focused ultrasound stimulation (FUS can be used to modulate neural activity with high spatial resolution. Phase-amplitude coupling (PAC between neuronal oscillations is tightly associated with cognitive processes, including learning, attention and memory. In this study, we investigated the effect of FUS on PAC between neuronal oscillations and established the relationship between the PAC index and ultrasonic intensity. The rat hippocampus was stimulated using focused ultrasound at different spatial-average pulse-average ultrasonic intensities (3.9 W/cm2, 9.6 W/cm2, and 19.2 W/cm2. The local field potentials (LFPs in the rat hippocampus were recorded before and after FUS. Then, we analyzed PAC between neuronal oscillations using a PAC calculation algorithm. Our results showed that FUS significantly modulated PAC between the theta (4-8 Hz and gamma (30-80 Hz bands and between the alpha (9-13 Hz and ripple (81-200 Hz bands in the rat hippocampus, and PAC increased with incremental increases in ultrasonic intensity.

  11. Spin polarized and density modulated phases in symmetric electron-electron and electron-hole bilayers.

    Science.gov (United States)

    Kumar, Krishan; Moudgil, R K

    2012-10-17

    We have studied symmetric electron-electron and electron-hole bilayers to explore the stable homogeneous spin phase and the feasibility of inhomogeneous charge-/spin-density ground states. The former is resolved by comparing the ground-state energies in states of different spin polarizations, while the latter is resolved by searching for a divergence in the wavevector-dependent static charge/spin susceptibility. For this endeavour, we have used the dielectric approach within the self-consistent mean-field theory of Singwi et al. We find that the inter-layer interactions tend to change an abrupt spin-polarization transition of an isolated layer into a nearly gradual one, even though the partially spin-polarized phases are not clearly stable within the accuracy of our calculation. The transition density is seen to decrease with a reduction in layer spacing, implying a suppression of spin polarization by inter-layer interactions. Indeed, the suppression shows up distinctly in the spin susceptibility computed from the spin-polarization dependence of the ground-state energy. However, below a critical layer spacing, the unpolarized liquid becomes unstable against a charge-density-wave (CDW) ground state at a density preceding full spin polarization, with the transition density for the CDW state increasing on further reduction in the layer spacing. Due to attractive e-h correlations, the CDW state is found to be more pronounced in the e-h bilayer. On the other hand, the static spin susceptibility diverges only in the long-wavelength limit, which simply represents a transition to the homogeneous spin-polarized phase.

  12. Patient information in radiation oncology: a cross-sectional pilot study using the EORTC QLQ-INFO26 module

    International Nuclear Information System (INIS)

    Adler, Johannes; Paelecke-Habermann, Yvonne; Jahn, Patrick; Landenberger, Margarete; Leplow, Bernd; Vordermark, Dirk

    2009-01-01

    The availability of alternative sources of information, e. g. the internet, may influence the quantity and quality of information cancer patients receive regarding their disease and treatment. The purpose of the present study was to assess perception of information in cancer patients during radiotherapy as well as media preferences and specifically the utilization of the internet. In a cross-sectional, single-centre study 94 patients currently undergoing radiotherapy were asked to complete two questionnaires. The EORTC QLQ-INFO26 module was used to assess the quality and quantity of information received by patients in the areas disease, medical tests, treatment, other services, different places of care and how to help themselves, as well as qualitative aspects as helpfulness of and satisfaction with this information. The importance of different media, in particular the internet, was investigated by a nine-item questionnaire. The response rate was n = 72 patients (77%). Patients felt best informed concerning medical tests (mean ± SD score 79 ± 22, scale 0-100) followed by disease (68 ± 21). Treatment (52 ± 24) and different places of care and other services (30 ± 36 and 30 ± 30, respectively) ranked last. 37% of patients were very satisfied and 37% moderately satisfied with the amount of information received, 61% wished more information. Among eight media, brochures, television and internet were ranked as most important. 41% used the internet themselves or via friends or family, mostly for research of classic and alternative treatment options. Unavailability and the necessity of computer skills were most mentioned obstacles. In a single-center pilot study, radiotherapy patients indicated having received most information about medical tests and their disease. Patients very satisfied with their information had received the largest amount of information. Brochures, television and internet were the most important media. Individual patient needs should be

  13. A first-order spectral phase transition in a class of periodically modulated Hermitian Jacobi matrices

    Directory of Open Access Journals (Sweden)

    Irina Pchelintseva

    2008-01-01

    Full Text Available We consider self-adjoint unbounded Jacobi matrices with diagonal \\(q_n = b_{n}n\\ and off-diagonal entries \\(\\lambda_n = n\\, where \\(b_{n}\\ is a \\(2\\-periodical sequence of real numbers. The parameter space is decomposed into several separate regions, where the spectrum of the operator is either purely absolutely continuous or discrete. We study the situation where the spectral phase transition occurs, namely the case of \\(b_{1}b_{2} = 4\\. The main motive of the paper is the investigation of asymptotics of generalized eigenvectors of the Jacobi matrix. The pure point part of the spectrum is analyzed in detail.

  14. Thermal behavior and phase identification of Valsartan by standard and temperature-modulated differential scanning calorimetry.

    Science.gov (United States)

    Skotnicki, Marcin; Gaweł, Agnieszka; Cebe, Peggy; Pyda, Marek

    2013-10-01

    Thermal behavior of angiotensin II type 1 (AT1) receptor antagonist, Valsartan (VAL), was examined employing thermogravimetric analysis (TGA), standard differential scanning calorimetry (DSC) and temperature-modulated differential scanning calorimetry (TMDSC). The stability of VAL was measured by TGA from 25 to 600°C. Decomposition of Valsartan starts around 160°C. The DSC curve shows two endotherms, occurring around 80°C and 100°C, related to evaporation of water and enthalpy relaxation, respectively. Valsartan was identified by DSC as an amorphous material and it was confirmed by X-ray powder diffraction. The glass transition of fresh Valsartan appears around 76°C (fictive temperature). TMDSC allows separation of the total heat flow rate into reversing and nonreversing parts. The nonreversing curve corresponds to the enthalpy relaxation and the reversing curve shows changes of heat capacity around 94°C. In the second run, TMDSC curve shows the glass transition process occurring at around 74°C. Results from standard DSC and TMDSC of Valsartan were compared over the whole range of temperature.

  15. The use of phase modulation optimization for power lasers. Minimizing the FM-AM conversion while preserving spectral broadening functionalities required for fusion

    International Nuclear Information System (INIS)

    Hocquet, St.

    2009-11-01

    This research thesis deals with the problem of phase modulations in power lasers (such as the MegaJoule laser which is developed in France) and their impact of different physical phenomena like the suppression of the stimulated Brillouin scattering (which is necessary to avoid optics damage) and the optical smoothing which allows a spatial homogenisation of focal stains. The author deeply discusses the phase modulation counterparts, and more particularly the FM-AM conversion which is the source of unwanted intensity modulation and of energy loss. He reports the development of a comprehensive modelling of phenomena generating FM-AM conversion on a power laser chain. He theoretically and experimentally studies two methods allowing the FM-AM conversion to be reduced to a given spectral distortion: the compensation of transfer functions and the modification of the phase modulation signal to make it less sensitive to spectral distortion effects. For this last method, he determines the ideal spectrum shape for the phase modulation, and proposes a method to approach it. He shows the feasibility of such a method and reports experiments showing to which extent these solutions may improve performance of power lasers. Finally, he proposed optimised solutions for the MegaJoule Laser

  16. All-optical OR/NOR Bi-functional logic gate by using cross-gain modulation in semiconductor optical amplifiers

    International Nuclear Information System (INIS)

    Choi, Kyoung Sun; Byun, Young Tae; Lee, Seok; Jhon, Young Min

    2010-01-01

    An OR/NOR bi-functional all-optical logic gate has been experimentally demonstrated at 10 Gbit/s by using cross-gain modulation (XGM) in only 2 semiconductor optical amplifiers (SOAs). One SOA was used for NOR operation and the other SOA was used for inversion to obtain OR operation. Numerical simulation has also been performed, which coincided well with the experimental results.

  17. Silicon Carbide (SiC) Device and Module Reliability, Performance of a Loop Heat Pipe Subjected to a Phase-Coupled Heat Input to an Acceleration Field

    Science.gov (United States)

    2016-05-01

    AFRL-RQ-WP-TR-2016-0108 SILICON CARBIDE (SiC) DEVICE AND MODULE RELIABILITY Performance of a Loop Heat Pipe Subjected to a Phase-Coupled...CARBIDE (SiC) DEVICE AND MODULE RELIABILITY Performance of a Loop Heat Pipe Subjected to a Phase-Coupled Heat Input to an Acceleration Field 5a...Shukla, K., “Thermo-fluid dynamics of Loop Heat Pipe Operation,” International Communications in Heat and Mass Transfer , Vol. 35, No. 8, 2008, pp

  18. Dysprosium separation from aqueous phase by non-dispersive solvent extraction employing hollow fibre membrane module

    International Nuclear Information System (INIS)

    Yadav, Kartikey K.; Singh, D.K.; Kain, V.

    2017-01-01

    Rare earth elements (REEs) consist of fourteen lanthanides and three elements which are Sc, Y and La resulting in total 17 REEs. In the last decade, these rare earths elements which have unique physical and chemical properties have been highly in demand for their application in almost all walks of life. Various methods such as ion exchange, precipitation and solvent extraction have been used to recover these elements from aqueous solutions. These traditional methods have some inherent disadvantages like handling of hazardous organic chemicals, ineffectiveness to recover a very low concentration of contaminated source etc. In this regard, an important method i.e. liquid membrane offers separation scheme; which combines the characteristics, of solvent extraction and solid membrane separation, to overcome the disadvantages of conventional techniques. Various experiments were carried out to evaluate the effect of feed acidity, metal ion concentration, carrier concentration, feed composition, flow rates and phase ratio on the transport of rare earths metal ions across the membrane

  19. Lunar Phase Modulates Circadian Gene Expression Cycles in the Broadcast Spawning Coral Acropora millepora.

    Science.gov (United States)

    Brady, Aisling K; Willis, Bette L; Harder, Lawrence D; Vize, Peter D

    2016-04-01

    Many broadcast spawning corals in multiple reef regions release their gametes with incredible temporal precision just once per year, using the lunar cycle to set the night of spawning. Moonlight, rather than tides or other lunar-regulated processes, is thought to be the proximate factor responsible for linking the night of spawning to the phase of the Moon. We compared patterns of gene expression among colonies of the broadcast spawning coral Acropora millepora at different phases of the lunar cycle, and when they were maintained under one of three experimentally simulated lunar lighting treatments: i) lunar lighting conditions matching those on the reef, or lunar patterns mimicking either ii) constant full Moon conditions, or iii) constant new Moon conditions. Normal lunar illumination was found to shift both the level and timing of clock gene transcription cycles between new and full moons, with the peak hour of expression for a number of genes occurring earlier in the evening under a new Moon when compared to a full Moon. When the normal lunar cycle is replaced with nighttime patterns equivalent to either a full Moon or a new Moon every evening, the normal monthlong changes in the level of expression are destroyed for most genes. In combination, these results indicate that daily changes in moonlight that occur over the lunar cycle are essential for maintaining normal lunar periodicity of clock gene transcription, and this may play a role in regulating spawn timing. These data also show that low levels of light pollution may have an impact on coral biological clocks. © 2016 Marine Biological Laboratory.

  20. Phase I trial of the androgen receptor modulator CR1447 in breast cancer patients

    Directory of Open Access Journals (Sweden)

    Martin Zweifel

    2017-09-01

    Full Text Available CR1447 (4-hydroxytestosterone, 4-OHT binds to the androgen receptor and has antiproliferative activity in both ER-positive and ER-negative/AR-positive breast cancer cells in preclinical studies. The objective of this first-in man trial was to evaluate the safety and to determine the dose of CR1447, administered as an ointment, for Phase II. Escalating doses (100, 200, 400 mg of CR1447 were administered topically on a daily basis to patients with ER-positive/AR-positive/HER2-negative advanced breast cancer pretreated with several lines of therapy. 14 patients have been treated for a total of 42 cycles. Two patients, one at dose level 100 mg and one at dose level 200 mg, showed early tumour progression and were replaced. Related adverse events were all ≤ grade 2 and included fatigue, bone and joint pain, stiffness, dry skin and mouth, nausea, sweating, urinary tract infection, rash, headache and distress. No drug-related dose-limiting toxicities (DLTs were seen. Two patients (17% achieved stable disease at 3 months. Pharmacokinetic analysis confirmed dose-dependent transdermal uptake of CR1447. 4-OH-androstenedione (4-OHA, a key metabolite of 4-OHT, was undetectable in most of the plasma samples. Urine metabolites of 4-OHT and 4-OHA indicate high exposure of 4-OHT after topical administration. Oestradiol serum concentrations did not increase, confirming preclinical data that CR1447 is not converted to estrogens in vivo. In conclusion, CR1447 administered transdermally as an ointment is well tolerated and appears to have single-agent activity in heavily pretreated ER-positive/HER2-negative breast cancer patients. The recommended phase II dose is 400 mg/day.