WorldWideScience

Sample records for a resonances

  1. Resonance and Neck Length for a Spherical Resonator

    Directory of Open Access Journals (Sweden)

    Emily Corning

    2011-06-01

    Full Text Available The relationship between the neck length of a spherical resonator and its period of fundamental resonance was investigated. This was done by measuring the frequency of fundamental resonance of the resonator at 6 different neck lengths. It was found that its resonance resembled Helmholtz resonance but was not that of ideal Helmholtz resonance.

  2. Resonator having a selection circuit for selecting a resonance mode

    OpenAIRE

    Verhoeven, C.J.

    1998-01-01

    Resonator provided with a resonating device and with a selection circuit for selecting a resonance mode. The selection circuit is formed by a first-order oscillator which is provided with a synchronization input and whose output is connected to the excitation input of the resonating device, the output of the resonating device being connected to the synchronization input of the first-order oscillator in order to synchronize said oscillator and the output signal of the resonator being derived f...

  3. Resonance in a head massager

    Science.gov (United States)

    Ribeiro, Jair Lúcio Prados

    2015-04-01

    Mechanical structures such as pendula, bridges, or buildings always exhibit one (or more) natural oscillation frequency.1 If that structure is subjected to oscillatory forces of this same frequency, resonance occurs, with consequent increase of the structure oscillation amplitude. There is no shortage of simple experiments for demonstrating resonance in high school classes using a variety of materials, such as saw blades,2 guitars,3 pendulums,4 wine glasses,5 bottles,6 Ping-Pong balls,7 and pearl strings.8 We present here an experimental demonstration using only an inexpensive head (or scalp) massager, which can be purchased for less than a dollar.

  4. Helmholtz Resonance in a Water Bottle

    Directory of Open Access Journals (Sweden)

    Annirudh Balachandran

    2011-01-01

    Full Text Available The resonance that occurs when blowing across the top of a water bottle filled with different volumes of water was studied. It was shown that, contrary to popular belief, a water bottle is not an ideal Helmholtz resonator. Resonance in a water bottle with an extendable neck was then studied to determine how the length of the neck affects the resonance. The results showed that ideal Helmholtz resonance occurs when the neck length was in a middle range, while for no neck a standing wave resonance occurs. For a very long neck the results were inconclusive.

  5. A Broadband Dipolar Resonance in THz Metamaterials

    CERN Document Server

    Sangala, Bagvanth Reddy; Gopal, Achanta Venu; Prabhu, S S

    2014-01-01

    We demonstrate a THz metamaterial with broadband dipole resonance originating due to the hybridization of LC resonances. The structure optimized by finite element method simulations is fabricated by electron beam lithography and characterized by terahertz time-domain spectroscopy. Numerically, we found that when two LC metamaterial resonators are brought together, an electric dipole resonance arises in addition to the LC resonances. We observed a strong dependence of the width of these resonances on the separation between the resonators. This dependence can be explained based on series and parallel RLC circuit analogies. The broadband dipole resonance appears when both the resonators are fused together. The metamaterial has a stopband with FWHM of 0.47 THz centered at 1.12 THz. The experimentally measured band features are in reasonable agreement with the simulated ones. The experimental power extinction ratio of THz in the stopbands is found to be 15 dB.

  6. Traces of a triboson resonance

    CERN Document Server

    Aguilar-Saavedra, J A; Lombardo, S

    2016-01-01

    We show that the relatively small but coincident excesses observed around 2 TeV in the ATLAS Run 1 and Run 2 hadronic diboson searches --- when a cut on the number of tracks in the fat jets is not applied --- and the null results of all remaining high-mass diboson searches are compatible with the decay of a triboson resonance $R$ into $WZ$ plus an extra particle $X$. These decays can take place via new neutral ($Y^0$) or charged ($Y^\\pm$) particles, namely $R \\to Y^0 \\, W$, with $Y^0 \\to Z X$, or $R \\to Y^\\pm Z$, with $Y^\\pm \\to W X$. An obvious candidate for such intermediate particle is a neutral one $Y^0$, given a $3.9\\sigma$ excess found at 650 GeV by the CMS Collaboration in searches for intermediate mass diboson resonances decaying to $ZV$, with $V=W,Z$. We discuss discovery strategies for triboson resonances with small modifications of existing hadronic searches.

  7. Traces of a triboson resonance

    Science.gov (United States)

    Aguilar-Saavedra, J. A.; Collins, J. H.; Lombardo, S.

    2016-09-01

    We show that the relatively small but coincident excesses observed around 2 TeV in the ATLAS Run 1 and Run 2 hadronic diboson searches — when a cut on the number of tracks in the fat jets is not applied — and the null results of all remaining high-mass diboson searches are compatible with the decay of a triboson resonance R into WZ plus an extra particle X. These decays can take place via new neutral ( Y 0) or charged ( Y ±) particles, namely R → Y 0 W, with Y 0 → ZX, or R → Y ± Z, with Y ± → WX. An obvious candidate for such intermediate particle is a neutral one Y 0, given a 3 .9 σ excess found at 650 GeV by the CMS Collaboration in searches for intermediate mass diboson resonances decaying to ZV, with V = W, Z. We discuss discovery strategies for triboson resonances with small modifications of existing hadronic searches.

  8. A Family of Resonant Vibration Control Formats

    DEFF Research Database (Denmark)

    Krenk, Steen; Høgsberg, Jan Becker

    Resonant control makes use of a controller with a resonance frequency and an equivalent damping ratio. A simple explicit calibration procedure is presented for a family of resonant controllers in which the frequency is tuned to the natural frequency of the targeted mode in such a way that the two...

  9. Controlling a diatomic shape resonance with non-resonant light

    CERN Document Server

    Aganoglu, Ruzin; Friedrich, Bretislav; González-Férez, Rosario; Koch, Christiane P

    2011-01-01

    A (diatomic) shape resonance is a metastable state of a pair of colliding atoms quasi-bound by the centrifugal barrier imposed by the angular momentum involved in the collision. The temporary trapping of the atoms' scattering wavefunction corresponds to an enhanced atom pair density at low interatomic separations. This leads to larger overlap of the wavefunctions involved in a molecule formation process such as photoassociation, rendering the process more efficient. However, for an ensemble of atoms, the atom pair density will only be enhanced if the energy of the resonance comes close to the temperature of the atomic ensemble. Herein we explore the possibility of controlling the energy of a shape resonance by shifting it toward the temperature of atoms confined in a trap. The shifts are imparted by the interaction of non-resonant light with the anisotropic polarizability of the atom pair, which affects both the centrifugal barrier and the pair's rotational and vibrational levels. We find that at laser intens...

  10. A new Fano resonance in measurement processes

    Science.gov (United States)

    Martínez-Argüello, A. M.; Martínez-Mares, M.; Cobián-Suárez, M.; Báez, G.; Méndez-Sánchez, R. A.

    2015-06-01

    In a wave resonant scattering process the interference of the continuous scattering amplitude with a discrete resonant state, both of the same undulatory nature, gives rise to a Fano resonance profile. We report experimental evidence of a new kind of Fano resonance, in which the continuous amplitude is of a different nature than that of the resonant wave. The continuous amplitude, of a electromagnetic nature, comes from the measurement process and induces a new type of prompt, or rapid, response of the system which we describe theoretically including this response as a direct process.

  11. Electron Shell as a Resonator

    International Nuclear Information System (INIS)

    Main principles of the resonance effect arising in the electron shells in interaction of the nuclei with electromagnetic radiation are analyzed and presented in the historical aspect. Principles of NEET are considered from a more general position, as compared to how this is usually presented. Characteristic features of NEET and its reverse, TEEN, as internal conversion processes are analyzed, and ways are offered of inducing them by laser radiation. The ambivalent role of the Pauli exclusion principles in NEET and TEEN processes is investigated.

  12. Observation of a hybrid spin resonance

    Science.gov (United States)

    Bai; Allgower; Ahrens; Alessi; Brown; Bunce; Cameron; Chu; Courant; Glenn; Huang; Jeon; Kponou; Krueger; Luccio; Makdisi; Lee; Ratner; Reece; Roser; Spinka; Syphers; Tsoupas; Underwood; van Asselt W; Williams

    2000-02-01

    A new type of spin depolarization resonance has been observed at the Brookhaven Alternating Gradient Synchrotron (AGS). This spin resonance is identified as a strong closed-orbit sideband around the dominant intrinsic spin resonance. The strength of the resonance was proportional to the 9th harmonic component of the horizontal closed orbit and proportional to the vertical betatron oscillation amplitude. This "hybrid" spin resonance cannot be overcome by the partial snake at the AGS, but it can be corrected by the harmonic orbit correctors. PMID:11017474

  13. Transmission resonance in a composite plasmonic structure

    CERN Document Server

    Yin, Xiao-gang; Wang, Qian-jin; Zhang, Chao; Zhu, Yong-yuan

    2009-01-01

    The design, fabrication, and optical properties of a composite plasmonic structure, a two-dimentional array of split-ring resonators inserted into periodic square holes of a metal film, have been reported. A new type of transmission resonance, which makes a significant difference from the conventional peaks, has been suggested both theoretically and experimentally. To understand this effect, a mechanism of ring- resonance induced dipole emission is proposed.

  14. A resonance mechanism of earthquakes

    CERN Document Server

    Flambaum, V V

    2015-01-01

    It had been observed in [1] that there are periodic 4-6 hours pulses of ? 200 ?Hz seismogravita- tional oscillations ( SGO ) before 95 % of powerful earthquakes. We explain this by beating between an oscillation eigenmode of a whole tectonic plate and a local eigenmode of an active zone which tranfers the oscillation energy from the tectonic plate to the active zone causing the eathrquake. Oscillation frequencies of the plate and ones of the active zone are tuned to a resonance by an additional pressure applied to the active zone due to collision of neighboring plates or convection in the upper mantia (plume). Corresponding theory may be used for short-term prediction of the earthquakes and tsunami.

  15. Coherence of magnetic resonators in a metamaterial

    Directory of Open Access Journals (Sweden)

    Yumin Hou

    2013-12-01

    Full Text Available The coherence of periodic magnetic resonators (MRs under oblique incidence is studied using simulations. The correlated phase of interaction including both the retardation effect and relative phase difference between two MRs is defined, and it plays a key role in the MR interaction. The correlated phase is anisotropic, as is the coherence condition. The coherence condition is the same as the Wood's anomaly and verified by the Fano resonance. This study shows that the applications of the Fano resonance of periodic MRs will become widespread owing to achieving the Fano resonance simply by tuning the incident angle.

  16. A novel resonant pressure sensor with boron diffused silicon resonator

    Science.gov (United States)

    Wang, Junbo; Shi, Xiaojing; Liu, Lei; Wu, Zhengwei; Chen, Deyong; Zhao, Jinmin; Li, Shourong

    2008-12-01

    To improve the performance of the micro-machined resonant pressure sensor and simplify its fabrication process, a novel structure is proposed in which the boron diffused silicon (up to 15um thickness) and the bulk silicon are used as the resonant beam and pressure membrane respectively. The structural parameters were optimized through FEM to achieve the better sensitivity, and the relationships between the structural parameters and the sensitivity were established. Moreover, the fabrication processes were discussed to increase the product rate and the pressure sensor with the optimal structural parameters was fabricated by the bulk silicon MEMS processes. In order to enhance the signal of the sensor and make the closed-looped control of the sensor easily, electromagnetic excitation and detection was applied. However there is so high noise coming from the distributing capacitances between the diffused silicon layer and electrodes that reduce the signal to noise ratio of the sensor. Through the analysis of the micro-structure of the sensor, the asymmetrical excitation circuit was used to reduce the noise and then the detection circuit was designed for this sensor. The resonator of the sensor was packaged in the low vacuum condition so that the high quality factor (Q) with about 10000 can be achieved. Experimental tests were carried out for the sensor over the range of -80kPa to 100kPa, the results show that the sensitivity of the sensor is about 20kHz/100kPa, the sensitivity is 0.01%F.S. and the nonlinearity is about 1.8%.

  17. Suprathreshold Stochastic Resonance in a Single Comparator

    Institute of Scientific and Technical Information of China (English)

    WANG Ren-Guo; LONG Zhang-Cai

    2007-01-01

    @@ Stochastic resonance usually appears when stimulus is too weak to overcome barriers in a nonlinear system.Unusually, we demonstrate that in a simple comparator as a prototype model, stochastic resonance can still occur when the stimulus is predominantly suprathreshold. This result provides new knowledge for understanding of mechanism underlying information process in biological systems and also finds applications in signal processing.

  18. A High-Q Microwave MEMS Resonator

    CERN Document Server

    Jian, Z; Yong, Z; Chen, Chen; Shixing, J

    2008-01-01

    A High-Q microwave (K band) MEMS resonator is presented, which empolys substrate integrated waveguide (SIW) and micromachined via-hole arrays by ICP process. Nonradiation dielectric waveguide (NRD) is formed by metal filled via-hole arrays and grounded planes. The three dimensional (3D) high resistivity silicon substrate filled cavity resonator is fed by current probes using CPW line. This monolithic resonator results in low cost, high performance and easy integration with planar cicuits. The measured quality factor is beyond 180 and the resonance frequency is 21GHz.It shows a good agreement with the simulation results. The chip size is only 4.7mm x 4.6mm x 0.5mm. Finally, as an example of applications, a filter using two SIW resonators is designed.

  19. Membrane metamaterial resonators with a sharp resonance: A comprehensive study towards practical terahertz filters and sensors

    Directory of Open Access Journals (Sweden)

    Yongyao Chen

    2012-06-01

    Full Text Available We investigate the resonant properties of high quality-factor membrane-based metamaterial resonators functioning in the terahertz regime. A number of factors, including the resonator geometry, dielectric loss, and most importantly the membrane thickness are found to extensively influence the resonance strength and quality factor of the sharp resonance. Further studies on the membrane thickness-dependent-sensitivity for sensing applications reveal that high quality-factor membrane metamaterials with a moderate thickness ranging from 10 to 50 μm are the most promising option towards developing realistic integrated terahertz filters and sensors.

  20. Resonance in a Cone-Topped Tube

    Directory of Open Access Journals (Sweden)

    Angus Cheng-Huan Chia

    2011-06-01

    Full Text Available The relationship between ratio of the upper opening diameter of a cone-topped cylinder to the cylinder diameter,and the ratio of the length of the air column to resonant period was examined. Plastic cones with upper openings ranging from 1.3 cm to 3.6 cm and tuning forks with frequencies ranging from 261.6 Hz to 523.3 Hz were used. The transition from a standing wave in a cylindrical column to a Helmholtz-type resonance in a resonant cavity with a narrow opening was observed.

  1. Kepler-16b: a resonant survivor

    CERN Document Server

    Popova, E A

    2012-01-01

    The planet Kepler-16b is known to follow a circumbinary orbit around a double system of two main-sequence stars. We construct stability diagrams in the "pericentric distance - eccentricity" plane, which show that Kepler-16b is in a hazardous vicinity to the chaos domain - just between the instability "teeth" in the space of orbital parameters. Kepler-16b survives, because it is close to the half-integer 11/2 orbital resonance with the central binary. The neighbouring resonance cells are vacant, because they are "purged" by Kepler-16b, due to overlap of first-order resonances with the planet.

  2. Prediction for a four-neutron resonance

    CERN Document Server

    Shirokov, A M; Mazur, A I; Mazur, I A; Roth, R; Vary, J P

    2016-01-01

    We utilize various {\\em ab initio} approaches to search for a low-lying resonance in the four-neutron ($4n$) system using the JISP16 realistic $NN$ interaction. Our most accurate prediction is obtained using a $J$-matrix extension of the No-Core Shell Model and suggests a $4n$ resonant state at an energy near $E_r = 0.8$ MeV with a width of approximately $\\Gamma = 1.4$ MeV.

  3. Fano resonances in a plasmonic waveguide system composed of stub coupled with a square cavity resonator

    International Nuclear Information System (INIS)

    A coupled plasmonic waveguide resonator system which can produce sharp and asymmetric Fano resonances was proposed and analyzed. Two Fano resonances are induced by the interactions between the narrow discrete whispering gallery modes in a plasmonic square cavity resonator and the broad spectrum of the metal–insulator–metal stub resonator. The relative peak amplitudes between the 1st and 2nd order Fano resonances can be adjusted by changing the structure parameters, such as the square cavity size, the stub size and the center-to-center distance between the square cavity and the stub resonators. And the 1st order Fano resonant peak, which is a standing-wave mode, will split into two resonant peaks (one standing-wave mode and one traveling-wave mode) when it couples with the 2nd Fano resonance. Also, the potential of the proposed Fano system as an integrated slow-light device and refractive index sensor was investigated. The results show that a maximum group index of about 100 can be realized, and a linear refractive index sensitivity of 938 nm/RIU with a figure of merit of about 1.35 × 104 can be obtained. (paper)

  4. Magnetic Resonance Imaging with a Dielectric Lens

    OpenAIRE

    Vazquez, F.; Marrufo, O.; MARTIN,R; Rodriguez, A. O.

    2009-01-01

    Recently, metamaterials have been introduced to improve the signal-to-noise ratio (SNR) of magnetic resonance images with very promising results. However, the use polymers in the generation of high quality images in magnetic resonance imaging has not been fully been investigated. These investigations explored the use of a dielectric periodical array as a lens to improve the image SNR generated with single surface coils. Commercial polycarbonate glazing sheets were used together with a circula...

  5. Double Fano resonances in a composite metamaterial possessing tripod plasmonic resonances

    OpenAIRE

    Lee, Y.U.; Choi, E. Y.; Kim, E S; Woo, J.H.; KANG, B.; Kim, J.; Park, Byung Cheol; Hong, T. Y.; Kim, Jae Hoon; Wu, J W

    2013-01-01

    By embedding four-rod resonators inside double-split ring resonators superlattice, a planar composite metamaterial possessing tripod plasmonic resonances is fabricated. Double Fano resonances are observed where a common subradiant driven oscillator is coupled with two superradiant oscillators. As a classical analogue of four-level tripod atomic system, the transmission spectrum of the composite metamaterial exhibits a double Fano-based coherent effect. Transfer of absorbed power between two s...

  6. Stochastic resonance during a polymer translocation process.

    Science.gov (United States)

    Mondal, Debasish; Muthukumar, M

    2016-04-14

    We have studied the occurrence of stochastic resonance when a flexible polymer chain undergoes a single-file translocation through a nano-pore separating two spherical cavities, under a time-periodic external driving force. The translocation of the chain is controlled by a free energy barrier determined by chain length, pore length, pore-polymer interaction, and confinement inside the donor and receiver cavities. The external driving force is characterized by a frequency and amplitude. By combining the Fokker-Planck formalism for polymer translocation and a two-state model for stochastic resonance, we have derived analytical formulas for criteria for emergence of stochastic resonance during polymer translocation. We show that no stochastic resonance is possible if the free energy barrier for polymer translocation is purely entropic in nature. The polymer chain exhibits stochastic resonance only in the presence of an energy threshold in terms of polymer-pore interactions. Once stochastic resonance is feasible, the chain entropy controls the optimal synchronization conditions significantly. PMID:27083746

  7. A transmission calibration method for superconducting resonators

    CERN Document Server

    Cataldo, Giuseppe; Barrentine, Emily M; Brown, Ari D; Moseley, Samuel H; U-Yen, Kongpop

    2014-01-01

    A method is proposed and experimentally explored for \\textit{in-situ} calibration of complex transmission data for superconducting microwave resonators. This cryogenic calibration method accounts for the instrumental transmission response between the vector network analyzer reference plane and the device calibration plane. Once calibrated, the observed resonator response was modeled in detail by two approaches. The first, a phenomenological model based on physically realizable rational functions, enables the extraction of multiple resonance frequencies and widths for coupled resonators without explicit specification of the circuit network. In the second, an ABCD-matrix representation for the distributed transmission line circuit is used to model the observed response from the characteristic impedance and propagation constant. When used in conjunction with electromagnetic simulations, the kinetic inductance fraction can be determined with this method with an accuracy of 2%. Datasets for superconducting microst...

  8. Stochastic resonance in a financial model

    Institute of Scientific and Technical Information of China (English)

    毛晓明; 孙锴; 欧阳颀

    2002-01-01

    We report on our model study of stochastic resonance in the stock market using numerical simulation and analysis.In the model, we take the interest rate as the external signal, the randomness of traders' behaviour as the noise, andthe stock price as the output. With computer simulations, we find that the system demonstrates a characteristic ofstochastic resonance as noise intensity varies. An analytical explanation is proposed.

  9. Tunable Fano resonance in a single-ring-resonator-based add/drop interferometer.

    Science.gov (United States)

    Wang, Kaiyang; Liu, Xiaoqi; Yu, Changqiu; Zhang, Yundong

    2013-07-10

    We theoretically study a single-ring-resonator-based add/drop interferometer to achieve tunable Fano resonance. The Fano resonance results from the interference of two resonant beams propagating in the ring resonator. The line shapes of the Fano resonance are tunable by controlling the coupling coefficients between the waveguide and ring resonator. The spectra of the drop port and through port of the add/drop interferometer are horizontally mirror-symmetric. A box-like spectral response can be produced with the proper coupling coefficient owing to the double resonances. When the phase difference between the two light inputs to the add/drop interferometer is compensated, a doubled free spectral range can be obtained. PMID:23852203

  10. Fano resonances in a multimode waveguide coupled to a high-Q silicon nitride ring resonator.

    Science.gov (United States)

    Ding, Dapeng; de Dood, Michiel J A; Bauters, Jared F; Heck, Martijn J R; Bowers, John E; Bouwmeester, Dirk

    2014-03-24

    Silicon nitride (Si3N4) optical ring resonators provide exceptional opportunities for low-loss integrated optics. Here we study the transmission through a multimode waveguide coupled to a Si3N4 ring resonator. By coupling single-mode fibers to both input and output ports of the waveguide we selectively excite and probe combinations of modes in the waveguide. Strong asymmetric Fano resonances are observed and the degree of asymmetry can be tuned through the positions of the input and output fibers. The Fano resonance results from the interference between modes of the waveguide and light that couples resonantly to the ring resonator. We develop a theoretical model based on the coupled mode theory to describe the experimental results. The large extension of the optical modes out of the Si3N4 core makes this system promising for sensing applications. PMID:24664026

  11. A mechanical memory with a dc modulation of nonlinear resonance

    Science.gov (United States)

    Noh, Hyunho; Shim, Seung-Bo; Jung, Minkyung; Khim, Zheong G.; Kim, Jinhee

    2010-07-01

    We present a mechanical memory device based on dynamic motion of a nanoelectromechanical (NEM) resonator. The NEM resonator exhibits clear nonlinear resonance characteristics which can be controlled by the dc bias voltage. For memory operations, the NEM resonator is driven to the nonlinear resonance region, and binary values are assigned to the two allowed states on the bifurcation branch. The transition between memory states is achieved by modulating the nonlinear resonance characteristics with dc bias voltage. Our device works at room temperature and modest vacuum conditions with a maximum operation frequency of about 5 kHz.

  12. Double Fano resonances in a composite metamaterial possessing tripod plasmonic resonances

    International Nuclear Information System (INIS)

    By embedding four-rod resonators inside a double-split ring resonator superlattice, a planar composite metamaterial possessing tripod plasmonic resonances is fabricated. Double Fano resonances are observed where a common subradiant driven oscillator is coupled with two superradiant oscillators. As a classical analogue of a four-level tripod atomic system, the extinction spectrum of the composite metamaterial exhibits a coherent effect based on double Fano resonances. Transfer of the absorbed power between two orthogonal superradiant oscillators is shown to be mediated by the common subradiant oscillator. (paper)

  13. A Diphoton Resonance from Bulk RS

    CERN Document Server

    Csaki, Csaba

    2016-01-01

    Recent LHC data hints at a 750 GeV mass resonance that decays into two photons. A significant feature of this resonance is that its decays to Higges and to any other Standard Model particles are so far too low to be detected. Such a state has a compelling explanation in terms of a scalar or a pseudoscalar that is strongly coupled to vector states charged under the Standard Model gauge groups. We argue that if the state is a scalar, some form of sequestering is likely to be necessary to naturally explain the suppressed scalar-Higgs interactions. Such a scenario is readily accommodated in bulk RS with a scalar localized in the bulk away from the Higgs. Turning this around, we argue that a good way to find the elusive bulk RS model might be the search for a resonance with prominent couplings to gauge bosons.

  14. Pyknometric volume measurement of a quasispherical resonator

    Science.gov (United States)

    Underwood, R.; Davidson, S.; Perkin, M.; Morantz, P.; Sutton, G.; de Podesta, M.

    2012-06-01

    We have measured the internal volume of a 1 litre, diamond-turned copper quasispherical resonator with a fractional uncertainty of approximately 1 part in 106 using two independent techniques. This is in response to the need for a uniquely accurate measurement of resonator volume, for the purpose of measuring the Boltzmann constant in pursuit of the redefinition of the kelvin. The first technique is a pyknometric measurement using water as a liquid of known density. We describe the development of a procedure that results in stable, reproducible volume measurements. We provide a detailed discussion of the factors that affect the water density, such as dissolved gases. The second technique is microwave resonance spectroscopy. Here, we measure the resonant frequencies of the TM1n modes and relate them to the dimensions of the resonator. We evaluate the frequency perturbations that arise from the coupling waveguides and the electrical resistivity of the copper surface. The results of the microwave measurements show evidence of a dielectric coating on the surface. We propose that this is an oxide layer and estimate its thickness from the microwave data. Finally, we compare the volume estimates from the two methods, and find that the difference is within the combined uncertainty.

  15. A diphoton resonance from bulk RS

    Science.gov (United States)

    Csáki, Csaba; Randall, Lisa

    2016-07-01

    Recent LHC data hinted at a 750 GeV mass resonance that decays into two photons. A significant feature of this resonance is that its decays to any other Standard Model particles would be too low to be detected so far. Such a state has a compelling explanation in terms of a scalar or a pseudoscalar that is strongly coupled to vector states charged under the Standard Model gauge groups. Such a scenario is readily accommodated in bulk RS with a scalar localized in the bulk away from but close to the Higgs. Turning this around, we argue that a good way to find the elusive bulk RS model might be the search for a resonance with prominent couplings to gauge bosons.

  16. A general model of resonance capture in planetary systems: First and second order resonances

    CERN Document Server

    Mustill, Alexander J

    2010-01-01

    Mean motion resonances are a common feature of both our own Solar System and of extrasolar planetary systems. Bodies can be trapped in resonance when their orbital semi-major axes change, for instance when they migrate through a protoplanetary disc. We use a Hamiltonian model to thoroughly investigate the capture behaviour for first and second order resonances. Using this method, all resonances of the same order can be described by one equation, with applications to specific resonances by appropriate scaling. We focus on the limit where one body is a massless test particle and the other a massive planet. We quantify how the the probability of capture into a resonance depends on the relative migration rate of the planet and particle, and the particle's eccentricity. Resonant capture fails for high migration rates, and has decreasing probability for higher eccentricities. More massive planets can capture particles at higher eccentricities and migration rates. We also calculate libration amplitudes and the offse...

  17. Lateral acoustic wave resonator comprising a suspended membrane of low damping resonator material

    Science.gov (United States)

    Olsson, Roy H.; El-Kady; , Ihab F.; Ziaei-Moayyed, Maryam; Branch; , Darren W.; Su; Mehmet F.,; Reinke; Charles M.,

    2013-09-03

    A very high-Q, low insertion loss resonator can be achieved by storing many overtone cycles of a lateral acoustic wave (i.e., Lamb wave) in a lithographically defined suspended membrane comprising a low damping resonator material, such as silicon carbide. The high-Q resonator can sets up a Fabry-Perot cavity in a low-damping resonator material using high-reflectivity acoustic end mirrors, which can comprise phononic crystals. The lateral overtone acoustic wave resonator can be electrically transduced by piezoelectric couplers. The resonator Q can be increased without increasing the impedance or insertion loss by storing many cycles or wavelengths in the high-Q resonator material, with much lower damping than the piezoelectric transducer material.

  18. A sound absorbing metasurface with coupled resonators

    Science.gov (United States)

    Li, Junfei; Wang, Wenqi; Xie, Yangbo; Popa, Bogdan-Ioan; Cummer, Steven A.

    2016-08-01

    An impedance matched surface is able, in principle, to totally absorb the incident sound and yield no reflection, and this is desired in many acoustic applications. Here we demonstrate a design of impedance matched sound absorbing surface with a simple construction. By coupling different resonators and generating a hybrid resonance mode, we designed and fabricated a metasurface that is impedance-matched to airborne sound at tunable frequencies with subwavelength scale unit cells. With careful design of the coupled resonators, over 99% energy absorption at central frequency of 511 Hz with a 50% absorption bandwidth of 140 Hz is achieved experimentally. The proposed design can be easily fabricated, and is mechanically stable. The proposed metasurface can be used in many sound absorption applications such as loudspeaker design and architectural acoustics.

  19. Basic dynamics at a multiple resonance

    International Nuclear Information System (INIS)

    The problem of multiple resonance is dealt with as it occurs in Celestial Mechanics and in non-linear Mechanics. In perturbation theory small divisors occur as a consequence of the fact that the flows in the phase space of the real system and the flows in the phase space of the so-called undisturbed system are not homeomorphic at all. Whatever the perturbation technique we adopt, the first step is to correct the topology of the undisturbed flows. It is shown that at a multiple resonance we are led to dynamical systems that are generally non-integrable. The basic representatives of these systems are the n-pendulums theta sup(:) sub(k) = σ sub(j)A sub(jk) sin theta sub(j). Multiple resonances are classified as syndetic or asyndetic following the eigenvalues of a quadratic form. Some degenerate cases are also presented. (Author)

  20. A bulk niobium superconducting quarter wave resonator

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Zvi, I. (Brookhaven National Lab., Upton, NY (United States)); Chiaveri, E. (European Organization for Nuclear Research, Geneva (Switzerland)); Elkonin, B.V. (Weizmann Inst. of Science, Rehovoth (Israel)); Facco, A.; Sokolowski, J.S. (Istituto Nazionale di Fisica Nucleare, Legnaro (Italy). Lab. Nazionale di Legnaro)

    1990-01-01

    A bath-cooled all-niobium 160 MHz quarter wave resonator prototype was constructed and tested. The objective of this research has been the development of a high performance accelerating element with {beta}{sub opt} {approx equal} 0.11 for the ALPI linac at the Laboratori Nazionali di Legnaro. The design of this resonator was based upon a previous 150 MHz model, with minor changes due to the different frequency and to modified welding procedure. An accelerating field of 5 MV/m was achieved at a power dissipation of 10 W and the low power Q was 2.4 {times} 10{sup 8}. The resonator could dissipate 70 W of power without thermal breakdown. 16 refs., 2 figs., 1 tab.

  1. Magnetic Resonance Imaging with a Dielectric Lens

    CERN Document Server

    Vazquez, F; Martin, R; Rodriguez, A O

    2009-01-01

    Recently, metamaterials have been introduced to improve the signal-to-noise ratio (SNR) of magnetic resonance images with very promising results. However, the use polymers in the generation of high quality images in magnetic resonance imaging has not been fully been investigated. These investigations explored the use of a dielectric periodical array as a lens to improve the image SNR generated with single surface coils. Commercial polycarbonate glazing sheets were used together with a circular coil to generate phantom images at 3 Tesla on a clinical MR imager.

  2. Nonlinearity and nonclassicality in a nanomechanical resonator

    Energy Technology Data Exchange (ETDEWEB)

    Teklu, Berihu [Clermont Universite, Blaise Pascal University, CNRS, PHOTON-N2, Institut Pascal, Aubiere Cedex (France); Universita degli Studi di Milano, Dipartimento di Fisica, Milano (Italy); Ferraro, Alessandro; Paternostro, Mauro [Queen' s University, Centre for Theoretical Atomic, Molecular, and Optical Physics, School of Mathematics and Physics, Belfast (United Kingdom); Paris, Matteo G.A. [Universita degli Studi di Milano, Dipartimento di Fisica, Milano (Italy)

    2015-12-15

    We address quantitatively the relationship between the nonlinearity of a mechanical resonator and the nonclassicality of its ground state. In particular, we analyze the nonclassical properties of the nonlinear Duffing oscillator (being driven or not) as a paradigmatic example of a nonlinear nanomechanical resonator. We first discuss how to quantify the nonlinearity of this system and then show that the nonclassicality of the ground state, as measured by the volume occupied by the negative part of the Wigner function, monotonically increases with the nonlinearity in all the working regimes addressed in our study. Our results show quantitatively that nonlinearity is a resource to create nonclassical states in mechanical systems. (orig.)

  3. A seismic metamaterial: The resonant metawedge

    Science.gov (United States)

    Colombi, Andrea; Colquitt, Daniel; Roux, Philippe; Guenneau, Sebastien; Craster, Richard V.

    2016-06-01

    Critical concepts from three different fields, elasticity, plasmonics and metamaterials, are brought together to design a metasurface at the geophysical scale, the resonant metawedge, to control seismic Rayleigh waves. Made of spatially graded vertical subwavelength resonators on an elastic substrate, the metawedge can either mode convert incident surface Rayleigh waves into bulk elastic shear waves or reflect the Rayleigh waves creating a “seismic rainbow” effect analogous to the optical rainbow for electromagnetic metasurfaces. Time-domain spectral element simulations demonstrate the broadband efficacy of the metawedge in mode conversion while an analytical model is developed to accurately describe and predict the seismic rainbow effect; allowing the metawedge to be designed without the need for extensive parametric studies and simulations. The efficiency of the resonant metawedge shows that large-scale mechanical metamaterials are feasible, will have application, and that the time is ripe for considering many optical devices in the seismic and geophysical context.

  4. A Mechanical Resonance Apparatus for Undergraduate Laboratories.

    Science.gov (United States)

    Jones, Christopher C.

    1995-01-01

    Reports the use of a heavy duty hacksaw blade and a 1000 turn pick-up coil to form the basis of a mechanical oscillator for a laboratory exercise in mechanical resonance designed for either the elementary undergraduate course or in association with an upper level mechanics course. (LZ)

  5. A superheterodyne spectrometer for electronic paramagnetic. Resonance

    International Nuclear Information System (INIS)

    After a few generalities about electron paramagnetic resonance, a consideration of different experimental techniques authorises the choice of a particular type of apparatus. An EPR superheterodyne spectrometer built in the laboratory and having a novel circuit is described in detail. With this apparatus, many experimental results have been obtained and some of these are described as example. (author)

  6. A microwave resonator for limiting depth sensitivity for electron paramagnetic resonance spectroscopy of surfaces

    OpenAIRE

    Sidabras, Jason W.; Varanasi, Shiv K.; Mett, Richard R.; Swarts, Steven G.; Swartz, Harold M.; Hyde, James S.

    2014-01-01

    A microwave Surface Resonator Array (SRA) structure is described for use in Electron Paramagnetic Resonance (EPR) spectroscopy. The SRA has a series of anti-parallel transmission line modes that provides a region of sensitivity equal to the cross-sectional area times its depth sensitivity, which is approximately half the distance between the transmission line centers. It is shown that the quarter-wave twin-lead transmission line can be a useful element for design of microwave resonators at fr...

  7. Resonant tunneling in a pulsed phonon field

    DEFF Research Database (Denmark)

    Kral, P.; Jauho, Antti-Pekka

    1999-01-01

    We theoretically investigate resonant tunneling through a single level assisted by short LO phonon pulses. The analysis is based on the recently developed nonequilibrium linked-cluster expansion [P. Kral, Phys. Rev. B 56, 7293 (1997)], extended in this work to transient situations, The nonequilib...

  8. Resonance fluorescence of a cold atom in a high-finesse resonator

    CERN Document Server

    Bienert, M; Torres, J M; Zippilli, S; Bienert, Marc; Morigi, Giovanna; Zippilli, Stefano

    2007-01-01

    We study the spectra of emission of a system composed by an atom, tightly confined inside a high-finesse resonator, when the atom is driven by a laser and is at steady state of the cooling dynamics induced by laser and cavity field. In general, the spectrum of resonance fluorescence and the spectrum at the cavity output contain complementary information about the dynamics undergone by the system. In certain parameter regimes, quantum interference effects between the scattering processes induced by cavity and laser field lead to the selective suppression of features of the resonance fluorescence spectrum, which are otherwise visible in the spectrum of laser-cooled atoms in free space.

  9. Resonance-spacing tuning over whole free spectral range in a single microring resonator

    Science.gov (United States)

    Gao, Ge; Yuan, Shuai; Li, Danping; Xia, Jinsong

    2016-03-01

    In this paper, we present a single microring resonator structure formed by incorporating a reflectivity-tunable loop mirror for the tuning of resonance spacing. Based on the optical mode-splitting in the resonator structure, spacing between two adjacent resonances can be tuned from zero to one whole free spectral range (FSR) by controlling the coupling strength between the two counter-propagating degenerate modes in the microring resonator. In experiment, by integrating metallic microheater, the resonance-spacing tuning over the whole FSR (1.17 nm) is achieved within 9.82 mW heating power dissipation. The device is expected to have potential applications in reconfigurable optical filtering and microwave photonics.

  10. Stochastic resonance and chaotic resonance in bimodal maps: A case study

    Indian Academy of Sciences (India)

    G Ambika; N V Sujatha; K P Harikrishnan

    2002-09-01

    We present the results of an extensive numerical study on the phenomenon of stochastic resonance in a bimodal cubic map. Both Gaussian random noise as well as deterministic chaos are used as input to drive the system between the basins. Our main result is that when two identical systems capable of stochastic resonance are coupled, the SNR of either system is enhanced at an optimum coupling strength. Our results may be relevant for the study of stochastic resonance in biological systems.

  11. A resonant dc-dc power converter assembly

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a resonant DC-DC power converter assembly comprising a first resonant DC-DC power converter and a second resonant DC-DC power converter having identical circuit topologies. A first inductor of the first resonant DC-DC power converter and a second inductor...... of the second resonant DC-DC power converter are configured for magnetically coupling the first and second resonant DC-DC power converters to each other to forcing substantially 180 degrees phase shift, or forcing substantially 0 degree phase shift, between corresponding resonant voltage waveforms of the first...... and second resonant DC-DC power converters. The first and second inductors are corresponding components of the first and second resonant DC-DC power converters....

  12. A Field of Resonant Learning

    DEFF Research Database (Denmark)

    Lindvang, Charlotte

    A mixed methods investigation og student esperiences and professionals' evaluation of their own competencies......A mixed methods investigation og student esperiences and professionals' evaluation of their own competencies...

  13. Direct measurement of the intrinsic linewidth of a resonant state

    Science.gov (United States)

    Kobos, Zachary; Reed, Mark

    2015-03-01

    We have applied inelastic electron tunneling spectroscopy (IETS) techniques to a resonantly-coupled system to determine quantitative differences in resonant versus non-resonant IETS. We use as a model system a set of GaAs-AlGaAs resonant tunneling diodes (RTDs)(footnote: with different barrier widths to tune resonant state linewidths and transmission coefficients. Modulation-broadening studies confirm theoretical predictions; however, the thermal dependence is markedly different than expected from classical IETS theory. An analysis of resonance shut-off reveals that the thermal dependence reflects the thermal broadening of the injector and resonant state density of states. Using this analysis, we show that one can extract both the transmission coefficient and the intrinsic linewidth of the resonant state. This is compared for RTDs of different tunneling barrier widths, and we observe the expected increase in resonance width for thinner barriers. This work was supported by the National Science Foundation.

  14. Simulation of a resonant inverter

    OpenAIRE

    Breda, David Pedro

    2015-01-01

    Mostly developed since the Industrial Revolution, the automation of systems and equipment around us is responsible for a technological progress and economic growth without precedents, but also by a relentless energy dependence. Currently, fossil fuels still tend to come as the main energy source, even in developed countries, due to the ease in its extraction and the mastery of the technology needed for its use. However, the perception of its ending availability, as well a...

  15. Controllable strong coupling between individual spin qubits and a transmission line resonator via nanomechanical resonators

    International Nuclear Information System (INIS)

    We investigate a hybrid quantum system where an individual electronic spin qubit (EQ) and a transmission line resonator (TLR) are connected by a nanomechanical resonator (NAMR). We analyze the possibility of realizing a strong coupling between the EQ and the TLR. Compared with a direct coupling between an EQ and a TLR, the achieved coupling can be stronger and controllable. The proposal might be used to implement a high-fidelity quantum state transfer between the spin qubit and the TLR, and is scalable to involve several individual EQ-NAMR coupled systems with a TLR. -- Highlights: ► Strong coupling of a spin qubit to a transmission line resonator is achieved. ► The coupling is mediated by a nanomechanical resonator. ► The coupling is controllable and stronger than the direct spin-resonator coupling.

  16. Resonance and Transcendence of a Bodily Presence

    DEFF Research Database (Denmark)

    Petersen, Rikke Munck; Farsø, Mads

    2016-01-01

    This article elucidates how film may offer itself as ‘resonance tool’ for both representation and conception of space that can strengthen an alternative, phenomenological and haptic position of transcendence in architecture, a position from which landscapes and cities are thought, planned...... films the article points to the film media as a sensory amplifier and its ability to present a subject’s awareness of its bodily presence and a ”feeling into” space based on Gernot Bohme’s Den Raum leiblicher Anwesenheit (Böhme 2006) and Giuliana Bruno’s concept of resonance (Bruno 2014). How film...... and its sound – if being integrated as design studio tool – comes to amplify sensory dimensions. The studio films illustrate how the surface of the film´s picture frame almost become like a skin, and with its surface and sound, projecting both a site and near sensual experience, the film media reflects...

  17. A microwave resonance dew-point hygrometer

    Science.gov (United States)

    Underwood, R. J.; Cuccaro, R.; Bell, S.; Gavioso, R. M.; Madonna Ripa, D.; Stevens, M.; de Podesta, M.

    2012-08-01

    We report the first measurements of a quasi-spherical microwave resonator used as a dew-point hygrometer. In conventional dew-point hygrometers, the condensation of water from humid gas flowing over a mirror is detected optically, and the mirror surface is then temperature-controlled to yield a stable condensed layer. In our experiments we flowed moist air from a humidity generator through a quasi-spherical resonator and detected the onset of condensation by measuring the frequency ratio of selected microwave modes. We verified the basic operation of the device over the dew-point range 9.5-13.5 °C by comparison with calibrated chilled-mirror hygrometers. These tests indicate that the microwave method may allow a quantitative estimation of the volume and thickness of the water layer which is condensed on the inner surface of the resonator. The experiments reported here are preliminary due to the limited time available for the work, but show the potential of the method for detecting not only water but a variety of other liquid or solid condensates. The robust all-metal construction should make the device appropriate for use in industrial applications over a wide range of temperatures and pressures.

  18. Resonance fluorescence in a waveguide geometry

    OpenAIRE

    Kocabaş, Şukrü Ekin; Rephaeli, Eden; Fan, Shanhui

    2011-01-01

    PHYSICAL REVIEW A 85, 023817 (2012) Resonance fluorescence in a waveguide geometry S¸ ¨ukr¨u Ekin Kocabas¸,1,* Eden Rephaeli,2,† and Shanhui Fan3,‡ 1Department of Electrical & Electronics Engineering, Koc¸ University, Rumeli Feneri Yolu TR-34450 Sarıyer, ˙Istanbul, Turkey 2Department of Applied Physics, Stanford University, Stanford, California 94305, USA 3Ginzton Laboratory, Department of Electrical Engineering, Stanford University, Stanford, California 94305, USA (Received...

  19. A New Observable for Identifying Dijet Resonances

    CERN Document Server

    Izaguirre, Eder; Yavin, Itay

    2014-01-01

    The development of techniques for identifying hadronic signals from the overwhelming multi-jet backgrounds is an important part of the Large Hadron Collider (LHC) program. Of prime importance are resonances decaying into a pair of partons, such as the Higgs and $\\rm W$/$\\rm Z$ bosons, as well as hypothetical new particles. We present a simple observable to help discriminate a dijet resonance from background that is effective even when the decaying resonance is not strongly boosted. We find consistent performance of the observable over a variety of processes and degree of boosts, and show that it leads to a reduction of the background by a factor of $3-5$ relative to signal at the price of $10-20\\%$ signal efficiency. This approach represents a significant increase in sensitivity for Standard Model (SM) measurements and searches for new physics that are dominated by systematic uncertainties, which is true of many analyses involving jets - particularly in the high-luminosity running of the LHC.

  20. A MEMS square Chladni plate resonator

    Science.gov (United States)

    Pala, Sedat; Azgın, Kıvanç

    2016-10-01

    This paper presents the design, fabrication and tests of a micro-fabricated MEMS ‘Chladni’ plate resonator. The proposed MEMS resonator has a square plate geometry having a side length of 1400 µm and a height of 35 µm. Its geometry and electrode layout are designed to analyze and test as many modes as possible. The MEMS plate is fabricated using a silicon-on-insulator process with a 35 µm thick text{1} \\text{1} \\text{1}> silicon layer on a glass substrate. Transverse vibration of the plate is investigated to obtain closed form natural frequencies and mode shapes, which are derived using the Rayleigh-Ritz energy method, with an electrostatic softening effect included. Closed form equations for the calculation of effective stiffness’, masses and natural frequencies of the two modes (mode (1,1) and mode (2,0)-(0,2)) are presented, with and without electrostatic softening. The analytical model is verified for those modes by finite-element simulations, frequency response tests in vacuum and laser Doppler vibrometer (LDV) experiments. The derived model deviates from the finite-element analysis by 3.35% for mode (1,1) and 6.15% for mode (2,0)-(0,2). For verification, the frequency responses of the plates are measured with both electrostatic excitation-detection at around 20 mTorr vacuum ambient and LDV at around 0.364 mTorr vacuum ambient. The resonance frequency and Q-factor of mode (1,1) are measured to be 104.2 kHz and 14 300, respectively. For mode (2,0)-(0,2), the measured resonance frequency and Q-factor are 156.68 kHz and 10 700, respectively. The presented LDV results also support both natural frequencies of interest and corresponding mode shapes of the plate structure.

  1. Cardiovascular magnetic resonance imaging - a pictorial review

    OpenAIRE

    Vijay Dahya; Spottiswoode, Bruce S.

    2010-01-01

    Cardiovascular magnetic resonance imaging (CMR) is a powerful problem-solving tool and arguably offers the most comprehensive assessment of cardiac morphology and function, as well as the opportunity of rebuilding the bridge between cardiologists and radiologists. The role of CMR-trained imaging physicists is also valuable, and many CMR centres harmoniously incorporate these three sub-specialty fields. This paper comprises an overview of several CMR techniques, outlining both the strengths...

  2. Cardiovascular magnetic resonance imaging - a pictorial review

    Directory of Open Access Journals (Sweden)

    Vijay Dahya

    2010-12-01

    Full Text Available Cardiovascular magnetic resonance imaging (CMR is a powerful problem-solving tool and arguably offers the most comprehensive assessment of cardiac morphology and function, as well as the opportunity of rebuilding the bridge between cardiologists and radiologists. The role of CMR-trained imaging physicists is also valuable, and many CMR centres harmoniously incorporate these three sub-specialty fields. This paper comprises an overview of several CMR techniques, outlining both the strengths and limitations of the modality.

  3. A Technique for Adjusting Eigenfrequencies of WGM Resonators

    Science.gov (United States)

    Strekalov, Dmitry; Savchenkov, Anatoliy; Maleki, Lute; Matsko, Andrey; Iltchenko, Vladimir; Martin, Jan

    2009-01-01

    A simple technique has been devised for making small, permanent changes in the eigenfrequencies (resonance frequencies) of whispering-gallery-mode (WGM) dielectric optical resonators that have high values of the resonance quality factor (Q). The essence of the technique is to coat the resonator with a thin layer of a transparent polymer having an index of refraction close to that of the resonator material. Successive small frequency adjustments can be made by applying successive coats. The technique was demonstrated on a calcium fluoride resonator to which successive coats of a polymer were applied by use of a hand-made wooden brush. To prevent temperature- related frequency shifts that could interfere with the verification of the effectiveness of this technique, the temperature of the resonator was stabilized by means of a three-stage thermoelectric cooler. Measurements of the resonator spectrum showed the frequency shifts caused by the successive coating layers.

  4. Cavity optomechanics on a microfluidic resonator

    CERN Document Server

    Kim, Kyu Hyun; Lee, Wonsuk; Liu, Jing; Tomes, Matthew; Fan, Xudong; Carmon, Tal

    2012-01-01

    Light pressure is known to excite or cool vibrations in microresonators for sensing quantum-optomechanical effects and we now show that it can be explored for investigations with liquids. Currently, optical resonances are utilized to detect analytes in liquids. However, optomechanical oscillations have never been excited when devices were immersed in liquid. This is because replacing the surrounding air with water inherently increases the acoustical impedance and the associated acoustical-radiation losses. Here we fabricate a hollow optomechanical bubble resonator with water inside, and use light pressure to excite 8 MHz - 140 MHz vibrations with 1 mW optical-threshold power and >2000 mechanical Q, constituting the first time that any microfluidic system is optomechanically actuated. Bridging between optomechanics and microfluidics will enable recently developed capillaries and on-chip bubbles to vibrate via optical excitation; and allow optomechanics with non-solid material phases including bio-analytes, sup...

  5. Nanodiamond graphitization: a magnetic resonance study

    International Nuclear Information System (INIS)

    We report on the first nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) study of the high-temperature nanodiamond-to-onion transformation. 1H, 13C NMR and EPR spectra of the initial nanodiamond samples and those annealed at 600, 700, 800 and 1800 ° C were measured. For the samples annealed at 600 to 800 ° C, our NMR data reveal the early stages of the surface modification, as well as a progressive increase in sp2 carbon content with increased annealing temperature. Such quantitative experimental data were recorded for the first time. These findings correlate with EPR data on the sensitivity of the dangling bond EPR line width to air content, progressing with rising annealing temperature, that evidences consequent graphitization of the external layers of the diamond core. The sample annealed at 1800 ° C shows complete conversion of nanodiamond particles into carbon onions. (paper)

  6. Direct Visualization of a Polariton Resonator in the THz Regime.

    Science.gov (United States)

    Stoyanov, Nikolay; Feurer, T; Ward, David; Statz, Eric; Nelson, Keith

    2004-05-31

    We report fabrication of a THz phonon-polariton resonator in a single crystal of LiNbO3 using femtosecond laser machining with high energy pulses. Fundamental and overtone resonator modes are excited selectively and monitored through spatiotemporal imaging. The resonator is integrated into a single solid-state platform that can include THz generation, manipulation, readout and other functionalities. PMID:19475075

  7. Resonance decay effect on conserved number fluctuations in a hadron resonance gas model

    CERN Document Server

    Mishra, D K; Netrakanti, P K; Mohanty, A K

    2016-01-01

    We study the effect of charged secondaries coming from resonance decay on the net-baryon, net-charge and net-strangeness fluctuations in high energy heavy-ion collisions within the hadron resonance gas (HRG) model. We emphasize the importance of including weak decays along with other resonance decays in the HRG, while comparing with the experimental observables. The effect of kinematic cuts on resonances and primordial particles on the conserved number fluctuations are also studied. The HRG model calculations with the inclusion of resonance decays and kinematical cuts are compared with the recent experimental data from STAR and PHENIX experiments. We find a good agreement between our model calculations and the experimental measurements for both net-proton and net-charge distributions.

  8. Internal Resonance in a Vibrating Beam: A Zoo of Nonlinear Resonance Peaks

    Science.gov (United States)

    Mangussi, Franco

    2016-01-01

    In oscillating mechanical systems, nonlinearity is responsible for the departure from proportionality between the forces that sustain their motion and the resulting vibration amplitude. Such effect may have both beneficial and harmful effects in a broad class of technological applications, ranging from microelectromechanical devices to edifice structures. The dependence of the oscillation frequency on the amplitude, in particular, jeopardizes the use of nonlinear oscillators in the design of time-keeping electronic components. Nonlinearity, however, can itself counteract this adverse response by triggering a resonant interaction between different oscillation modes, which transfers the excess of energy in the main oscillation to higher harmonics, and thus stabilizes its frequency. In this paper, we examine a model for internal resonance in a vibrating elastic beam clamped at its two ends. In this case, nonlinearity occurs in the form of a restoring force proportional to the cube of the oscillation amplitude, which induces resonance between modes whose frequencies are in a ratio close to 1:3. The model is based on a representation of the resonant modes as two Duffing oscillators, coupled through cubic interactions. Our focus is put on illustrating the diversity of behavior that internal resonance brings about in the dynamical response of the system, depending on the detailed form of the coupling forces. The mathematical treatment of the model is developed at several approximation levels. A qualitative comparison of our results with previous experiments and numerical calculations on elastic beams is outlined. PMID:27648829

  9. Internal Resonance in a Vibrating Beam: A Zoo of Nonlinear Resonance Peaks.

    Science.gov (United States)

    Mangussi, Franco; Zanette, Damián H

    2016-01-01

    In oscillating mechanical systems, nonlinearity is responsible for the departure from proportionality between the forces that sustain their motion and the resulting vibration amplitude. Such effect may have both beneficial and harmful effects in a broad class of technological applications, ranging from microelectromechanical devices to edifice structures. The dependence of the oscillation frequency on the amplitude, in particular, jeopardizes the use of nonlinear oscillators in the design of time-keeping electronic components. Nonlinearity, however, can itself counteract this adverse response by triggering a resonant interaction between different oscillation modes, which transfers the excess of energy in the main oscillation to higher harmonics, and thus stabilizes its frequency. In this paper, we examine a model for internal resonance in a vibrating elastic beam clamped at its two ends. In this case, nonlinearity occurs in the form of a restoring force proportional to the cube of the oscillation amplitude, which induces resonance between modes whose frequencies are in a ratio close to 1:3. The model is based on a representation of the resonant modes as two Duffing oscillators, coupled through cubic interactions. Our focus is put on illustrating the diversity of behavior that internal resonance brings about in the dynamical response of the system, depending on the detailed form of the coupling forces. The mathematical treatment of the model is developed at several approximation levels. A qualitative comparison of our results with previous experiments and numerical calculations on elastic beams is outlined. PMID:27648829

  10. Resonant-tunnelling diode oscillator using a slot-coupled quasioptical open resonator

    Science.gov (United States)

    Stephan, K. D.; Brown, E. R.; Parker, C. D.; Goodhue, W. D.; Chen, C. L.

    1991-01-01

    A resonant-tunneling diode has oscillated at X-band frequencies in a microwave circuit consisting of a slot antenna coupled to a semiconfocal open resonator. Coupling between the open resonator and the slot oscillator improves the noise-to-carrier ratio by about 36 dB relative to that of the slot oscillator alone in the 100-200 kHz range. A circuit operating near 10 GHz has been designed as a scale model for millimeter- and submillimeter-wave applications.

  11. Cyclotron resonance in a cathode ray tube

    International Nuclear Information System (INIS)

    Absorption of the RF energy by the electron beam in a cathode ray tube due to the cyclotron resonance is described. The cathode ray tube is placed within a Helmholtz coils system supplied by a sawtooth current generator. In order to generate RF field and to detect RF absorption a gate dip-meter equipped with a FET transistor is used. The bias voltage variations of the FET transistors as a function of the magnetic field are recorded. The operating point of the cathode ray tube has been chosen so that the relaxation oscillations of the detection system can be observed. (authors)

  12. Tunable cavity resonator including a plurality of MEMS beams

    Energy Technology Data Exchange (ETDEWEB)

    Peroulis, Dimitrios; Fruehling, Adam; Small, Joshua Azariah; Liu, Xiaoguang; Irshad, Wasim; Arif, Muhammad Shoaib

    2015-10-20

    A tunable cavity resonator includes a substrate, a cap structure, and a tuning assembly. The cap structure extends from the substrate, and at least one of the substrate and the cap structure defines a resonator cavity. The tuning assembly is positioned at least partially within the resonator cavity. The tuning assembly includes a plurality of fixed-fixed MEMS beams configured for controllable movement relative to the substrate between an activated position and a deactivated position in order to tune a resonant frequency of the tunable cavity resonator.

  13. A study of trapped mode resonances in asymmetric X-shape resonator for frequency selective surface

    Science.gov (United States)

    Chen, Kejian; Liu, Hong; Wang, Yiqi; Zhu, Yiming

    2013-08-01

    FSS is a two-dimensional periodic array of resonating metallic-dielectric structures, When FSS device steps into Terahertz range from microwave range, it is studied as THz functional components (such as Terahertz filter, Terahertz biochemical sensor, etc.) to promote the functionality of the THz spectroscopy/imaging system. When the device requires a narrow band transmission window for frequency selecting or a high electric field concentration in certain area to improve its sensitivity for sensing, normally, a high quality (Q) resonant structure can give helps. Recently, high-Q resonance induced by trapped mode resonance i studied widely in FSS research areas. To induce trapped mode resonance, one can simply break the symmetric of the unit structure of FSS. In this paper, several asymmetric X-shaped resonators for FSS working in terahertz range have been studied numerically. To compare the behaviour of X-shape resonator under different conditions (with additional part: Heart lines, Shoulder lines, Wrap or Shoes squares), a common platform (θ=60, θis angle of X shape) which is suitable for most of cases was used to make the study more meaningful. As the field enhancement behaviour is related to the trapped mode introduced by the asymmetric structure, we propose such kind of device to be used as a high quality filter or as a sensing element for biochemical samples.

  14. Resonator quantum electrodynamics on a microtrap chip; Resonator-Quantenelektrodynamik auf einem Mikrofallenchip

    Energy Technology Data Exchange (ETDEWEB)

    Steinmetz, Tilo

    2008-04-29

    In the present dissertation experiments on resonator quantum electrodynamics on a microtrap chip are described. Thereby for the first time single atoms catched in a chip trap could be detected. For this in the framework of this thesis a novel optical microresonator was developed, which can because of its miniaturization be combined with the microtrap technique introduced in our working group for the manipulation of ultracold atoms. For this resonator glass-fiber ends are used as mirror substrates, between which a standing light wave is formed. With such a fiber Fabry-Perot resonator we obtain a finess of up to {approx}37,000. Because of the small mode volumina in spite of moderate resonator quality the coherent interaction between an atom and a photon can be made so large that the regime of the strong atom-resonator coupling is reached. For the one-atom-one-photon coupling rate and the one-atom-one-photon cooperativity thereby record values of g{sub 0}=2{pi}.300 MHz respectively C{sub 0}=210 are reached. Just so for the first time the strong coupling regime between a Bose-Einstein condensate (BEC) and the field of a high-quality resonator could be reached. The BEC was thereby by means of the magnetic microtrap potentials deterministically brought to a position within the resonator and totally transformed in a well defined antinode of an additionally optical standing-wave trap. The spectrum of the coupled atom-resonator system was measured for different atomic numbers and atom-resonator detunings, whereby a collective vacuum Rabi splitting of more than 20 GHz could be reached. [German] In der vorliegenden Dissertation werden Experimente zur Resonator-Quantenelektrodynamik auf einem Mikrofallenchip beschrieben. Dabei konnte u. a. erstmals einzelne, in einer Chipfalle gefangene Atome detektiert werden. Hier fuer wurde im Rahmen dieser Arbeit ein neuartiger optischer Mikroresonator entwickelt, der sich dank seiner Miniaturisierung mit der in unserer Arbeitsgruppe

  15. Exponential decay and resonances in a driven system

    CERN Document Server

    Briet, Philippe

    2012-01-01

    We study the resonance phenomena for time periodic perturbations of a Hamiltonian $H$ on the Hilbert space $L^2(\\mathbb R ^d)$. Here, resonances are characterized in terms of time behavior of the survival probability. Our approach uses the Floquet-Howland formalism combined with the results of L. Cattaneo, J.M. Graf and W. Hunziker on resonances for time independent perturbations.

  16. Phonon blockade in a nanomechanical resonator resonantly coupled to a qubit

    CERN Document Server

    Xu, Xun-Wei; Liu, Yu-xi

    2016-01-01

    We study phonon statistics in a nanomechanical resonator (NAMR) which is resonantly coupled to a qubit. We find that there are two different mechanisms for phonon blockade in such a resonantly coupled NAMR-qubit system. One is due to the strong anharmonicity of the NAMR-qubit system with large coupling strength; the other one is due to the destructive interference between different paths for two-phonon excitation in the NAMR-qubit system with a moderate coupling strength. In order to enlarge the mean phonon number for strong phonon antibunching with a moderate NAMR-qubit coupling strength, we assume that two external driving fields are applied to the NAMR and qubit, respectively. In this case, we find that the phonon blockades under two mechanisms can appear at the same frequency regime by optimizing the strength ratio and phase difference of the two external driving fields.

  17. A one-kilogram quartz resonator as a mass standard.

    Science.gov (United States)

    Vig, John; Howe, David

    2013-02-01

    The SI unit of mass, the kilogram, is defined by a single artifact, the International Prototype Kilogram. This artifact, the primary mass standard, suffers from long-term instabilities that are neither well understood nor easily monitored. A secondary mass standard consisting of a 1-kg quartz resonator in ultrahigh vacuum is proposed. The frequency stability of such a resonator is likely to be far higher than the mass stability of the primary mass standard. Moreover, the resonator would provide a link to the SI time-interval unit. When compared with a laboratory-grade atomic frequency standard or GPS time, the frequency of the resonator could be monitored, on a continuous basis, with 10(-15) precision in only a few days of averaging. It could also be coordinated, worldwide, with other resonator mass standards without the need to transport the standards.

  18. A microwave resonator integrated on a polymer microfluidic chip

    Science.gov (United States)

    Kiss, S. Z.; Rostas, A. M.; Heidinger, L.; Spengler, N.; Meissner, M. V.; MacKinnon, N.; Schleicher, E.; Weber, S.; Korvink, J. G.

    2016-09-01

    We describe a novel stacked split-ring type microwave (MW) resonator that is integrated into a 10 mm by 10 mm sized microfluidic chip. A straightforward and scalable batch fabrication process renders the chip suitable for single-use applications. The resonator volume can be conveniently loaded with liquid sample via microfluidic channels patterned into the mid layer of the chip. The proposed MW resonator offers an alternative solution for compact in-field measurements, such as low-field magnetic resonance (MR) experiments requiring convenient sample exchange. A microstrip line was used to inductively couple MWs into the resonator. We characterised the proposed resonator topology by electromagnetic (EM) field simulations, a field perturbation method, as well as by return loss measurements. Electron paramagnetic resonance (EPR) spectra at X-band frequencies were recorded, revealing an electron-spin sensitivity of 3.7 ·1011spins ·Hz - 1 / 2G-1 for a single EPR transition. Preliminary time-resolved EPR experiments on light-induced triplet states in pentacene were performed to estimate the MW conversion efficiency of the resonator.

  19. Resonant activation: a strategy against bacterial persistence

    International Nuclear Information System (INIS)

    A bacterial colony may develop a small number of cells genetically identical to, but phenotypically different from, other normally growing bacteria. These so-called persister cells keep themselves in a dormant state and thus are insensitive to antibiotic treatment, resulting in serious problems of drug resistance. In this paper, we proposed a novel strategy to 'kill' persister cells by triggering them to switch, in a fast and synchronized way, into normally growing cells that are susceptible to antibiotics. The strategy is based on resonant activation (RA), a well-studied phenomenon in physics where the internal noise of a system can constructively facilitate fast and synchronized barrier crossings. Through stochastic Gilliespie simulation with a generic toggle switch model, we demonstrated that RA exists in the phenotypic switching of a single bacterium. Further, by coupling single cell level and population level simulations, we showed that with RA, one can greatly reduce the time and total amount of antibiotics needed to sterilize a bacterial population. We suggest that resonant activation is a general phenomenon in phenotypic transition, and can find other applications such as cancer therapy

  20. Electrodynamics of a ring-shaped spiral resonator

    Science.gov (United States)

    Maleeva, N.; Fistul, M. V.; Karpov, A.; Zhuravel, A. P.; Averkin, A.; Jung, P.; Ustinov, A. V.

    2014-02-01

    We present analytical, numerical, and experimental investigations of electromagnetic resonant modes of a compact monofilar Archimedean spiral resonator shaped in a ring, with no central part. Planar spiral resonators are interesting as components of metamaterials for their compact deep-subwavelength size. Such resonators couple primarily to the magnetic field component of the incident electromagnetic wave, offering properties suitable for magnetic meta-atoms. Surprisingly, the relative frequencies of the resonant modes follow the sequence of the odd numbers as f1:f2:f3:f4… = 1:3:5:7…, despite the nearly identical boundary conditions for electromagnetic fields at the extremities of the resonator. In order to explain the observed spectrum of resonant modes, we show that the current distribution inside the spiral satisfies a particular Carleman type singular integral equation. By solving this equation, we obtain a set of resonant frequencies. The analytically calculated resonance frequencies and the current distributions are in good agreement with experimental data and the results of numerical simulations. By using low-temperature laser scanning microscopy of a superconducting spiral resonator, we compare the experimentally visualized ac current distributions over the spiral with the calculated ones. Theory and experiment agree well with each other. Our analytical model allows for calculation of a detailed three-dimensional magnetic field structure of the resonators.

  1. Raman Scattering at Resonant or Near-Resonant Conditions: A Generalized Short-Time Approximation

    Institute of Scientific and Technical Information of China (English)

    Abdelsalam Mohammed; Yu-Ping Sun; Quan Miao; Hans (A)gren; Faris Gel'mukhanov

    2012-01-01

    We investigate the dynamics of resonant Raman scattering in the course of the frequency detuning.The dephasing in the time domain makes the scattering fast when the photon energy is tuned from the absorption resonance.This makes frequency detuning to act as a camera shutter with a regulated scattering duration and provides a practical tool of controlling the scattering time in ordinary stationary measurements.The theory is applied to resonant Raman spectra of a couple of few-mode model systems and to trans-1,3,5-hexatriene and guanine-cytosine (G-C) Watson-Crick base pairs (DNA) molecules.Besides some particular physical effects,the regime of fast scattering leads to a simplification of the spectrum as well as to the scattering theory itself.Strong overtones appear in the Raman spectra when the photon frequency is tuned in the resonant region,while in the mode of fast scattering,the overtones are gradually quenched when the photon frequency is tuned more than one vibrational quantum below the first absorption resonance.The detuning from the resonant region thus leads to a strong purification of the Raman spectrum from the contamination by higher overtones and soft modes and purifies the spectrum also in terms of avoidance of dissociation and interfering fluorescence decay of the resonant state.This makes frequency detuning a very useful practical tool in the analysis of the resonant Raman spectra of complex systems and considerably improves the prospects for using the Raman effect for detection of foreign substances at ultra-low concentrations.

  2. Off-resonance energy absorption in a linear Paul trap due to mass selective resonant quenching

    Energy Technology Data Exchange (ETDEWEB)

    Sivarajah, I.; Goodman, D. S.; Wells, J. E.; Smith, W. W. [Department of Physics, University of Connecticut, Storrs, Connecticut 06269 (United States); Narducci, F. A. [Naval Air Systems Command, EO Sensors Division, Bldg 2187, Suite 3190 Patuxent River, Maryland 20670 (United States)

    2013-11-15

    Linear Paul traps (LPT) are used in many experimental studies such as mass spectrometry, atom-ion collisions, and ion-molecule reactions. Mass selective resonant quenching (MSRQ) is implemented in LPT either to identify a charged particle's mass or to remove unwanted ions from a controlled experimental environment. In the latter case, MSRQ can introduce undesired heating to co-trapped ions of different mass, whose secular motion is off resonance with the quenching ac field, which we call off-resonance energy absorption (OREA). We present simulations and experimental evidence that show that the OREA increases exponentially with the number of ions loaded into the trap and with the amplitude of the off-resonance external ac field.

  3. Off-resonance energy absorption in a linear Paul trap due to mass selective resonant quenching.

    Science.gov (United States)

    Sivarajah, I; Goodman, D S; Wells, J E; Narducci, F A; Smith, W W

    2013-11-01

    Linear Paul traps (LPT) are used in many experimental studies such as mass spectrometry, atom-ion collisions, and ion-molecule reactions. Mass selective resonant quenching (MSRQ) is implemented in LPT either to identify a charged particle's mass or to remove unwanted ions from a controlled experimental environment. In the latter case, MSRQ can introduce undesired heating to co-trapped ions of different mass, whose secular motion is off resonance with the quenching ac field, which we call off-resonance energy absorption (OREA). We present simulations and experimental evidence that show that the OREA increases exponentially with the number of ions loaded into the trap and with the amplitude of the off-resonance external ac field. PMID:24289382

  4. Off-resonance energy absorption in a linear Paul trap due to mass selective resonant quenching

    CERN Document Server

    Sivarajah, I; Wells, J E; Narducci, F A; Smith, W W

    2013-01-01

    Linear Paul r.f. ion traps (LPT) are used in many experimental studies such as mass spectrometry, atom-ion collisions and ion-molecule reactions. Mass selective resonant quenching (MSRQ) is implemented in LPT either to identify a charged particle's mass or to remove unwanted ions from a controlled experimental environment. In the latter case, MSRQ can introduce undesired heating to co-trapped ions of different mass, whose secular motion is off resonance with the quenching ac field, which we call off-resonance energy absorption (OREA). We present simulations and experimental evidence that show that the OREA increases exponentially with the number of ions loaded into the trap and with the amplitude of the off-resonance external ac field.

  5. A new nucleon resonance in eta photoproduction

    CERN Document Server

    Choi, Ki-Seok; Hosaka, Atsushi; Kim, Hyun-Chul

    2007-01-01

    We present in this talk recent investigations on the nucleon-like resonance N*(1675) newly found in eta photoproduction by the GRAAL, Tohoku LNS-gamma and CB-ELSA collaborations. We focus on the production mechanism of the N*(1675), examining its spin and parity theoretically within the framework of the effective Lagrangian method. We expliucitly consider D_{13}(1520), S_{11}(1535), S_{11}(1650), D_{15}(1675), P_{11}(1710), P_{13}(1720) as well as possible background contributions. We calculate the differential cross sections and beam asymmetries for the neutron and proton targets. It turns out that there is manifest isospin asymmetry in eta photoproduction, which can be explained by the asymmetry in the transition magnetic moments: mu_{gamma p p*} =resonance may be identified as a non-strangeness member of the baryon antidecuplet.

  6. A hyperpolarized equilibrium for magnetic resonance

    Science.gov (United States)

    Hövener, Jan-Bernd; Schwaderlapp, Niels; Lickert, Thomas; Duckett, Simon B.; Mewis, Ryan E.; Highton, Louise A. R.; Kenny, Stephen M.; Green, Gary G. R.; Leibfritz, Dieter; Korvink, Jan G.; Hennig, Jürgen; von Elverfeldt, Dominik

    2013-12-01

    Nuclear magnetic resonance spectroscopy and imaging (MRI) play an indispensable role in science and healthcare but use only a tiny fraction of their potential. No more than ≈10 p.p.m. of all 1H nuclei are effectively detected in a 3-Tesla clinical MRI system. Thus, a vast array of new applications lays dormant, awaiting improved sensitivity. Here we demonstrate the continuous polarization of small molecules in solution to a level that cannot be achieved in a viable magnet. The magnetization does not decay and is effectively reinitialized within seconds after being measured. This effect depends on the long-lived, entangled spin-order of parahydrogen and an exchange reaction in a low magnetic field of 10-3 Tesla. We demonstrate the potential of this method by fast MRI and envision the catalysis of new applications such as cancer screening or indeed low-field MRI for routine use and remote application.

  7. A search for resonant Z pair production

    Energy Technology Data Exchange (ETDEWEB)

    Boveia, Antonio [Univ. of California, Santa Barbara, CA (United States)

    2008-12-01

    I describe a search for anomalous production of Z pairs through a new massive resonance X in 2.5-2.9 fb-1 of p$\\bar{p}$ collisions at √s = 1.96 TeV using the CDFII Detector at the Fermilab Tevatron. I reconstruct Z pairs through their decays to electrons, muons, and quarks. To achieve perhaps the most efficient lepton reconstruction ever used at CDF, I apply a thorough understanding of the detector and new reconstruction software heavily revised for this purpose. In particular, I have designed and employ new general-purpose algorithms for tracking at large η in order to increase muon acceptance. Upon analyzing the unblinded signal samples, I observe no X → ZZ candidates and set upper limits on the production cross section using a Kaluza-Klein graviton-like acceptance.

  8. Tunable Geometric Fano Resonances in a Metal/Insulator Stack

    CERN Document Server

    Grotewohl, Herbert

    2014-01-01

    A metal-insulator-metal-insulator stack is shown to have a Fano resonance in the angular domain. The metal/insulator stack consists of two interacting subsystems, a metallic waveguide mode and a surface plasmon mode, coupled by a finite layer metal film. The two modes in close spatial proximity interfere destructively resulting in level repulsion of two metal/insulator stack modes. By adding a coupling prism to momentum match the input EM field, the reflected field exhibits a geometric Fano resonance. Changes to the waveguide insulator permittivity and thickness are shown to tune the geometric Fano resonance. The geometric Fano resonance is also tuned by variations of the exterior insulator permittivity. At a given frequency, the geometric Fano resonance can be tuned to desired lineshape. In addition, this tunability allows for a geometric Fano resonance for any frequency in the visible range.

  9. Chest magnetic resonance imaging: a protocol suggestion

    Directory of Open Access Journals (Sweden)

    Bruno Hochhegger

    2015-12-01

    Full Text Available Abstract In the recent years, with the development of ultrafast sequences, magnetic resonance imaging (MRI has been established as a valuable diagnostic modality in body imaging. Because of improvements in speed and image quality, MRI is now ready for routine clinical use also in the study of pulmonary diseases. The main advantage of MRI of the lungs is its unique combination of morphological and functional assessment in a single imaging session. In this article, the authors review most technical aspects and suggest a protocol for performing chest MRI. The authors also describe the three major clinical indications for MRI of the lungs: staging of lung tumors; evaluation of pulmonary vascular diseases; and investigation of pulmonary abnormalities in patients who should not be exposed to radiation.

  10. Flow-excited acoustic resonance of a Helmholtz resonator: Discrete vortex model compared to experiments

    International Nuclear Information System (INIS)

    The acoustic resonance in a Helmholtz resonator excited by a low Mach number grazing flow is studied theoretically. The nonlinear numerical model is established by coupling the vortical motion at the cavity opening with the cavity acoustic mode through an explicit force balancing relation between the two sides of the opening. The vortical motion is modeled in the potential flow framework, in which the oscillating motion of the thin shear layer is described by an array of convected point vortices, and the unsteady vortex shedding is determined by the Kutta condition. The cavity acoustic mode is obtained from the one-dimensional acoustic propagation model, the time-domain equivalent of which is given by means of a broadband time-domain impedance model. The acoustic resistances due to radiation and viscous loss at the opening are also taken into account. The physical processes of the self-excited oscillations, at both resonance and off-resonance states, are simulated directly in the time domain. Results show that the shear layer exhibits a weak flapping motion at the off-resonance state, whereas it rolls up into large-scale vortex cores when resonances occur. Single and dual-vortex patterns are observed corresponding to the first and second hydrodynamic modes. The simulation also reveals different trajectories of the two vortices across the opening when the first and second hydrodynamic modes co-exist. The strong modulation of the shed vorticity by the acoustic feedback at the resonance state is demonstrated. The model overestimates the pressure pulsation amplitude by a factor 2, which is expected to be due to the turbulence of the flow which is not taken into account. The model neglects vortex shedding at the downstream and side edges of the cavity. This will also result in an overestimation of the pulsation amplitude

  11. Flow-excited acoustic resonance of a Helmholtz resonator: Discrete vortex model compared to experiments

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Xiwen; Jing, Xiaodong, E-mail: jingxd@buaa.edu.cn; Sun, Xiaofeng [School of Energy and Power Engineering, Beihang University, Beijing 100191 (China)

    2015-05-15

    The acoustic resonance in a Helmholtz resonator excited by a low Mach number grazing flow is studied theoretically. The nonlinear numerical model is established by coupling the vortical motion at the cavity opening with the cavity acoustic mode through an explicit force balancing relation between the two sides of the opening. The vortical motion is modeled in the potential flow framework, in which the oscillating motion of the thin shear layer is described by an array of convected point vortices, and the unsteady vortex shedding is determined by the Kutta condition. The cavity acoustic mode is obtained from the one-dimensional acoustic propagation model, the time-domain equivalent of which is given by means of a broadband time-domain impedance model. The acoustic resistances due to radiation and viscous loss at the opening are also taken into account. The physical processes of the self-excited oscillations, at both resonance and off-resonance states, are simulated directly in the time domain. Results show that the shear layer exhibits a weak flapping motion at the off-resonance state, whereas it rolls up into large-scale vortex cores when resonances occur. Single and dual-vortex patterns are observed corresponding to the first and second hydrodynamic modes. The simulation also reveals different trajectories of the two vortices across the opening when the first and second hydrodynamic modes co-exist. The strong modulation of the shed vorticity by the acoustic feedback at the resonance state is demonstrated. The model overestimates the pressure pulsation amplitude by a factor 2, which is expected to be due to the turbulence of the flow which is not taken into account. The model neglects vortex shedding at the downstream and side edges of the cavity. This will also result in an overestimation of the pulsation amplitude.

  12. On Resonance: A Critical Pluralistic Inquiry into Advertising Rhetoric.

    OpenAIRE

    Edward F. McQuarrie; Mick, David Glen

    1992-01-01

    Print ads exhibit resonance when they combine wordplay with a relevant picture to create ambiguity and incongruity. This article uses multiple perspectives and methods within a framework of critical pluralism to investigate advertising resonance. Semiotic text analyses, a content analysis of contemporary magazine ads, two experiments, and phenomenological interviews combine to yield insights into the operation, prevalence, impact and experience of resonance. Specifically, the two experiments ...

  13. A XOR Threshold Logic Implementation Through Resonant Tunneling Diode

    OpenAIRE

    Nitesh Kumar Dixit; Vinod Kumari

    2012-01-01

    Resonant tunneling diodes (RTDs) have functional versatility and high speed switching capability. The integration of resonant tunneling diodes and MOS transistor makes threshold gates and logics. The design and fabrication of linear threshold gates will be presented based on a mono stable bis table transition logic element. Each of its input terminals consist out of a resonant tunnelling diode merged with a transistor device. The circuit models of RTD and MOSFET are simulated in HSPICE. Two i...

  14. Electromagnetically induced absorption in a three-resonator metasurface system.

    Science.gov (United States)

    Zhang, Xueqian; Xu, Ningning; Qu, Kenan; Tian, Zhen; Singh, Ranjan; Han, Jiaguang; Agarwal, Girish S; Zhang, Weili

    2015-01-01

    Mimicking the quantum phenomena in metamaterials through coupled classical resonators has attracted enormous interest. Metamaterial analogs of electromagnetically induced transparency (EIT) enable promising applications in telecommunications, light storage, slow light and sensing. Although the EIT effect has been studied extensively in coupled metamaterial systems, excitation of electromagnetically induced absorption (EIA) through near-field coupling in these systems has only been sparsely explored. Here we present the observation of the EIA analog due to constructive interference in a vertically coupled three-resonator metamaterial system that consists of two bright and one dark resonator. The absorption resonance is one of the collective modes of the tripartite unit cell. Theoretical analysis shows that the absorption arises from a magnetic resonance induced by the near-field coupling of the three resonators within the unit cell. A classical analog of EIA opens up opportunities for designing novel photonic devices for narrow-band filtering, absorptive switching, optical modulation, and absorber applications. PMID:26023061

  15. A Magnetic Resonance Measurement Technique for Rapidly Switched Gradient Magnetic Fields in a Magnetic Resonance Tomograph

    Directory of Open Access Journals (Sweden)

    K. Bartušek

    2003-01-01

    Full Text Available This paper describes a method for measuring of the gradient magnetic field in Nuclear Magnetic Resonance (NMR tomography, which is one of the modern medical diagnostic methods. A very important prerequisite for high quality imaging is a gradient magnetic field in the instrument with exactly defined properties. Nuclear magnetic resonance enables us to measure the pulse gradient magnetic field characteristics with high accuracy. These interesting precise methods were designed, realised, and tested at the Institute of Scientific Instruments (ISI of the Academy of Sciences of the Czech Republic. The first of them was the Instantaneous Frequency (IF method, which was developed into the Instantaneous Frequency of Spin Echo (IFSE and the Instantaneous Frequency of Spin Echo Series (IFSES methods. The above named methods are described in this paper and their a comparison is also presented.

  16. Design of a superconducting low beta niobium resonator

    Indian Academy of Sciences (India)

    Prakash Potukuchi; Amit Roy

    2012-04-01

    The proposed high current injector for the superconducting Linac at the InterUniversity Accelerator Centre will have several accelerating structures, including a superconducting module which will contain low beta niobium resonators. A prototype resonator for the low beta module has been designed. The resonator has been carefully modelled to optimize the electromagnetic parameters. In order to validate them, a room-temperature copper model has been built and tested. In this paper we present details of the electromagnetic design of the low beta resonator, briefly discuss the mechanical and engineering design, and present results from the measurements on the room-temperature copper model.

  17. Fluctuation Reduction in a Si Micromechanical Resonator Tuned to Nonlinear Internal Resonance

    Science.gov (United States)

    Strachan, B. Scott; Czaplewski, David; Chen, Changyao; Dykman, Mark; Lopez, Daniel; Shaw, Steven

    2015-03-01

    We describe experimental and theoretical results on an unusual behavior of fluctuations when the system exhibits internal resonance. We study the fundamental flexural mode (FFM) of a Si microbeam. The FFM is electrically actuated and detected. It is resonantly nonlinearly coupled to another mode, which is not directly accessible and has a frequency nearly three times the FFM frequency. Both the FFM and the passive mode have long lifetimes. We find that the passive mode can be a ``sink'' for fluctuations of the FFM. This explains the recently observed dramatic decrease of these fluctuations at nonlinear resonance. The re-distribution of the vibration amplitudes and the fluctuations is reminiscent of what happens at level anti-crossing in quantum mechanics. However, here it is different because of interplay of the dependence of the vibration frequency of the FFM on its amplitude due to internal nonlinearity and the nonlinear resonance with the passive mode. We study both the response of the system to external resonant driving and also the behavior of the system in the presence of a feedback loop. The experimental and theoretical results are in good agreement.

  18. Electroproduction of Roper Resonance in a Meson Cloud Model

    Institute of Scientific and Technical Information of China (English)

    CHEN Dian-Yong; DONG Yu-Bing

    2008-01-01

    The Q2 dependencies of Roper resonance (N* (1440)) helicity amplitudes have been discussed based on two assumptions:(I) the Roper resonance is an excitation of one of the three quarks,and (ii) the quarks are surrounded by a pion-meson cloud.Our study shows that the mixing of the ground state in the Roper wavefunction caused by the pion meson cloud together with the pion meson cloud itself is crucial for the predictions of the photoproduction amplitudes of the Roper resonance.It is found that our model can give a good description for the helicity amplitudes of the Roper resonance comparing with the experimental measurement.

  19. Lineshape Engineering in an All-Pass Ring Resonator with Backreflection Coupled to a Symmetrical Fabry-Perot Resonator

    KAUST Repository

    Melnikov, Vasily A.

    2012-11-10

    We derive transfer functions for an all-pass ring resonator with internal backreflection coupled to a symmetrical Fabry-Perot resonator and demonstrate electromagnetically induced transparency-like and Fano-like lineshapes tunable by backreflection in the ring resonator.

  20. Bragg Resonator Cyclotron Resonance Maser Experiments Driven by a Microsecond, Intense Electron Beam Accelerator

    Science.gov (United States)

    Choi, Jin Joo

    The cyclotron resonance maser (CRM) has proven to be attractive for many high power microwave applications such as fusion plasma heating, radar/communications, and high gradient RF accelerators. Most of the previous CRM experiments with MV electron beams have been conducted with short (gyrotron modes. Considerably less power from the TE_{11} gyro -BWO was observed for the Bragg resonator with ripples fully -outward. The microwave emission from the TE_ {21} absolute instability in the Bragg resonator with ripples fully-outward was successfully suppressed by lowering the cavity magnetic field. These three undesired oscillations, (TE _{21} absolute instability, TE _{11} gyro-BWO, TE _{51} second and third harmonic), were the most serious competing modes in the present Bragg resonator CRM experiments, apparently suppressing the TE _{31} CARM oscillation. For the Bragg resonator with ripples half-inward, we have performed gyrotron experiments with a high current electron beam. In these experiments, we have observed mode competition between the TE_{21 } absolute instability and the TE_ {11} gyro-BWO interaction by the use of frequency measurements and gas breakdown diagnostics.

  1. Impact of resonance regeneration and decay on the net proton fluctuations in a hadron resonance gas

    Energy Technology Data Exchange (ETDEWEB)

    Nahrgang, Marlene, E-mail: marlene.nahrgang@phy.duke.edu [Department of Physics, Duke University, 27708-0305, Durham, NC (United States); Frankfurt Institute for Advanced Studies (FIAS), Ruth-Moufang-Str. 1, 60438, Frankfurt am Main (Germany); Bluhm, Marcus [Department of Physics, North Carolina State University, 27695, Raleigh, NC (United States); Alba, Paolo [Dipartimento di Fisica, Università degli Studi di Torino and INFN, Sezione di Torino, via Pietro Giuria 1, 10125, Turin (Italy); Bellwied, Rene; Ratti, Claudia [Department of Physics, University of Houston, 77204, Houston, TX (United States)

    2015-12-01

    We investigate net proton fluctuations as important observables measured in heavy-ion collisions within the hadron resonance gas (HRG) model. Special emphasis is given to effects which are a priori not inherent in a thermally and chemically equilibrated HRG approach. In particular, we point out the importance of taking into account the successive regeneration and decay of resonances after the chemical freeze-out, which lead to a randomization of the isospin of nucleons and thus to additional fluctuations in the net proton number. We find good agreement between our model results and the recent STAR measurements of the higher-order moments of the net proton distribution.

  2. Impact of resonance regeneration and decay on the net proton fluctuations in a hadron resonance gas

    Energy Technology Data Exchange (ETDEWEB)

    Nahrgang, Marlene [Duke University, Department of Physics, Durham, NC (United States); Frankfurt Institute for Advanced Studies (FIAS), Frankfurt am Main (Germany); Bluhm, Marcus [North Carolina State University, Department of Physics, Raleigh, NC (United States); Alba, Paolo [Universita degli Studi di Torino, Dipartimento di Fisica, Turin (Italy); INFN, Turin (Italy); Bellwied, Rene; Ratti, Claudia [University of Houston, Department of Physics, Houston, TX (United States)

    2015-12-15

    We investigate net proton fluctuations as important observables measured in heavy-ion collisions within the hadron resonance gas (HRG) model. Special emphasis is given to effects which are a priori not inherent in a thermally and chemically equilibrated HRG approach. In particular, we point out the importance of taking into account the successive regeneration and decay of resonances after the chemical freeze-out, which lead to a randomization of the isospin of nucleons and thus to additional fluctuations in the net proton number. We find good agreement between our model results and the recent STAR measurements of the higher-order moments of the net proton distribution. (orig.)

  3. Study of Nonpolaritons in a Kerr Nonlinear Optical Resonator

    Institute of Scientific and Technical Information of China (English)

    WAN Jin-Yin; CHENG Ze

    2006-01-01

    We find that in a Kerr nonlinear optical resonator, the photon system possesses a new kind of quasiparticle,the nonpolariton. The existence of nonpolaritons should be testified by observing the energy density dependence of the velocity and squeezing of nonpolaritons. As we have investigated, the transition energy density of a Kerr nonlinear optical resonator is larger than that of a normal state.

  4. Effect of energy and momentum conservation on fluid resonances for resonant magnetic perturbations in a tokamak

    International Nuclear Information System (INIS)

    In this paper, the impact of momentum and energy conservation of the collision operator in the kinetic description for Resonant Magnetic Perturbations (RMPs) in a tokamak is studied. The particle conserving differential collision operator of Ornstein-Uhlenbeck type is supplemented with integral parts such that energy and momentum are conserved. The application to RMP penetration in a tokamak shows that energy conservation in the electron collision operator is important for the quantitative description of plasma shielding effects at the resonant surface. On the other hand, momentum conservation in the ion collision operator does not significantly change the results

  5. Magnetic resonance imaging of a brain abscess

    International Nuclear Information System (INIS)

    Magnetic resonance imaging (MRI) was performed on 13 patients with brain abscesses, and the alternation of MRI findings, as correlated with the progression of brain-abscess formation, was reviewed. In the cerebritis stage, spin-echo images showed a high intensity, and inversion-recovery images, a low intensity, due to inflammation and edema. The spin-echo images were very sensitive in delineating the brain edema; however, it was difficult to distinguish the inflammation from the surrounding edema. In the capsule stage, due to the accumulation of purulent material, the central necrotic area was demonstrated as a low-intensity area, while the capsule of the abscess was revealed as an iso-intensity ring on the inversion-recovery images. The central necrotic area also decreased in intensity on spin-echo images in the later period of this stage. With contrast enhancement (Gd-DTPA), the SR image showed the capsule as a high-intensity ring. MRI was found to be a useful method for estimating the process of the formation of a brain abscess. (author)

  6. Magnetic resonance imaging of a brain abscess

    Energy Technology Data Exchange (ETDEWEB)

    Oikawa, Akihiro; Kagawa, Mizuo; Yatoh, Seiji; Izawa, Masahiro; Ujiie, Hiroshi; Sakaguchi, Jun; Onda, Hideaki; Kitamura, Kohichi

    1988-06-01

    Magnetic resonance imaging (MRI) was performed on 13 patients with brain abscesses, and the alternation of MRI findings, as correlated with the progression of brain-abscess formation, was reviewed. In the cerebritis stage, spin-echo images showed a high intensity, and inversion-recovery images, a low intensity, due to inflammation and edema. The spin-echo images were very sensitive in delineating the brain edema; however, it was difficult to distinguish the inflammation from the surrounding edema. In the capsule stage, due to the accumulation of purulent material, the central necrotic area was demonstrated as a low-intensity area, while the capsule of the abscess was revealed as an iso-intensity ring on the inversion-recovery images. The central necrotic area also decreased in intensity on spin-echo images in the later period of this stage. With contrast enhancement (Gd-DTPA), the SR image showed the capsule as a high-intensity ring. MRI was found to be a useful method for estimating the process of the formation of a brain abscess.

  7. Modelling a singly resonant, intracavity ring optical parametric oscillator

    DEFF Research Database (Denmark)

    Buchhave, Preben; Tidemand-Lichtenberg, Peter; Wei, Hou;

    2003-01-01

    We study theoretically and experimentally the dynamics of a single-frequency, unidirectional ring laser with an intracavity nonlinear singly resonant OPO-crystal in a coupled resonator. We find for a range of operating conditions good agreement between model results and measurements of the laser ...

  8. Eigenvalue study of a chaotic resonator

    International Nuclear Information System (INIS)

    The field of quantum chaos comprises the study of the manifestations of classical chaos in the properties of the corresponding quantum systems. Within this work, we compute the eigenfrequencies that are needed for the level spacing analysis of a microwave resonator with chaotic characteristics. The major challenges posed by our work are: first, the ability of the approaches to tackle the large scale eigenvalue problem and second, the capability to extract many, i.e. order of thousands, eigenfrequencies for the considered cavity. The first proposed approach for an accurate eigenfrequency extraction takes into consideration the evaluated electric field computations in time domain of a superconducting cavity and by means of signal-processing techniques extracts the eigenfrequencies. The second approach is based on the finite element method with curvilinear elements, which transforms the continuous eigenvalue problem to a discrete generalized eigenvalue problem. Afterwards, the Lanczos algorithm is used for the solution of the generalized eigenvalue problem. In the poster, a summary of the applied algorithms, as well as, critical implementation details together with the simulation results are provided.

  9. A time domain based method for the accurate measurement of Q-factor and resonance frequency of microwave resonators

    International Nuclear Information System (INIS)

    We present a novel method to determine the resonant frequency and quality factor of microwave resonators which is faster, more stable, and conceptually simpler than the yet existing techniques. The microwave resonator is pumped with the microwave radiation at a frequency away from its resonance. It then emits an exponentially decaying radiation at its eigen-frequency when the excitation is rapidly switched off. The emitted microwave signal is down-converted with a microwave mixer, digitized, and its Fourier transformation (FT) directly yields the resonance curve in a single shot. Being a FT based method, this technique possesses the Fellgett (multiplex) and Connes (accuracy) advantages and it conceptually mimics that of pulsed nuclear magnetic resonance. We also establish a novel benchmark to compare accuracy of the different approaches of microwave resonator measurements. This shows that the present method has similar accuracy to the existing ones, which are based on sweeping or modulating the frequency of the microwave radiation

  10. A time domain based method for the accurate measurement of Q-factor and resonance frequency of microwave resonators

    Energy Technology Data Exchange (ETDEWEB)

    Gyüre, B.; Márkus, B. G.; Bernáth, B.; Simon, F., E-mail: ferenc.simon@univie.ac.at [Department of Physics, Budapest University of Technology and Economics and MTA-BME Lendület Spintronics Research Group (PROSPIN), P.O. Box 91, H-1521 Budapest (Hungary); Murányi, F. [Foundation for Research on Information Technologies in Society (IT’IS), Zeughausstrasse 43, 8004 Zurich (Switzerland)

    2015-09-15

    We present a novel method to determine the resonant frequency and quality factor of microwave resonators which is faster, more stable, and conceptually simpler than the yet existing techniques. The microwave resonator is pumped with the microwave radiation at a frequency away from its resonance. It then emits an exponentially decaying radiation at its eigen-frequency when the excitation is rapidly switched off. The emitted microwave signal is down-converted with a microwave mixer, digitized, and its Fourier transformation (FT) directly yields the resonance curve in a single shot. Being a FT based method, this technique possesses the Fellgett (multiplex) and Connes (accuracy) advantages and it conceptually mimics that of pulsed nuclear magnetic resonance. We also establish a novel benchmark to compare accuracy of the different approaches of microwave resonator measurements. This shows that the present method has similar accuracy to the existing ones, which are based on sweeping or modulating the frequency of the microwave radiation.

  11. Collective resonant modes of a meta-surface

    OpenAIRE

    Felbacq, Didier; Rousseau, Emmanuel; Kling, Emmanuel

    2013-01-01

    A periodic layer of resonant scatterers is considered in the dipolar approximation. An asymptotic expression for the field diffracted is given in terms of an impedance operator. It is shown that surface Bloch modes appear as a collective effect due to the resonances of the scatterers.

  12. A model for ferrite-loaded transversely biased coaxial resonators

    DEFF Research Database (Denmark)

    Acar, Öncel; Zhurbenko, Vitaliy; Johansen, Tom Keinicke

    2013-01-01

    This work describes a simple model for shortened coaxial cavity resonators with transversely biased ferrite elements. The ferrite allows the resonance frequency to be tuned, and the presented model provides a method of approximately calculating these frequencies to generate the tuning curve...

  13. Diphoton resonance from a warped extra dimension

    Science.gov (United States)

    Bauer, Martin; Hörner, Clara; Neubert, Matthias

    2016-07-01

    We argue that extensions of the Standard Model (SM) with a warped extra dimension, which successfully address the hierarchy and flavor problems of elementary particle physics, can provide an elegant explanation of the 750 GeV diphoton excess recently reported by ATLAS and CMS. A gauge-singlet bulk scalar with {O} (1) couplings to fermions is identified as the new resonance S, and the vector-like Kaluza-Klein excitations of the SM quarks and leptons mediate its loop-induced couplings to photons and gluons. The electroweak gauge symmetry almost unambiguously dictates the bulk matter content and hence the hierarchies of the Sto γ γ, W W,ZZ,Zγ, toverline{t} and dijet decay rates. We find that the S → Zγ decay mode is strongly suppressed, such that Br( S → Zγ) /Br( S → γγ) boson is solved in analogy with the Higgs boson by localizing it near the infrared brane. The infinite sums over the Kaluza-Klein towers of fermion states converge and can be calculated in closed form with a remarkably simple result. Reproducing the observed pp → S → γγ signal requires Kaluza-Klein masses in the multi-TeV range, consistent with bounds from flavor physics and electroweak precision observables.

  14. Diphoton resonance from a warped extra dimension

    Science.gov (United States)

    Bauer, Martin; Hörner, Clara; Neubert, Matthias

    2016-07-01

    We argue that extensions of the Standard Model (SM) with a warped extra dimension, which successfully address the hierarchy and flavor problems of elementary particle physics, can provide an elegant explanation of the 750 GeV diphoton excess recently reported by ATLAS and CMS. A gauge-singlet bulk scalar with {O} (1) couplings to fermions is identified as the new resonance S, and the vector-like Kaluza-Klein excitations of the SM quarks and leptons mediate its loop-induced couplings to photons and gluons. The electroweak gauge symmetry almost unambiguously dictates the bulk matter content and hence the hierarchies of the Sto γ γ, W W,ZZ,Zγ, toverline{t} and dijet decay rates. We find that the S → Zγ decay mode is strongly suppressed, such that Br( S → Zγ) /Br( S → γγ) Kaluza-Klein towers of fermion states converge and can be calculated in closed form with a remarkably simple result. Reproducing the observed pp → S → γγ signal requires Kaluza-Klein masses in the multi-TeV range, consistent with bounds from flavor physics and electroweak precision observables.

  15. A census of transient orbital resonances encountered during binary inspiral

    CERN Document Server

    Ruangsri, Uchupol

    2013-01-01

    Transient orbital resonances have recently been identified as potentially important to the inspiral of small bodies into large black holes. These resonances occur as the inspiral evolves through moments in which two fundamental orbital frequencies, $\\Omega_\\theta$ and $\\Omega_r$, are in a small integer ratio to one another. Previous work has demonstrated that a binary's parameters are "kicked" each time the inspiral passes through a resonance, changing the orbit's characteristics relative to a model that neglects resonant effects. In this paper, we use exact Kerr geodesics coupled to an accurate but approximate model of inspiral to survey orbital parameter space and estimate how commonly one encounters long-lived orbital resonances. We find that the most important resonances last for a few hundred orbital cycles at mass ratio $10^{-6}$, and that resonances are almost certain to occur during the time that a large mass ratio binary would be a target of gravitational-wave observations. Resonances appear to be ub...

  16. A loop-gap resonator for chirality-sensitive nuclear magneto-electric resonance (NMER)

    Science.gov (United States)

    Garbacz, Piotr; Fischer, Peer; Krämer, Steffen

    2016-09-01

    Direct detection of molecular chirality is practically impossible by methods of standard nuclear magnetic resonance (NMR) that is based on interactions involving magnetic-dipole and magnetic-field operators. However, theoretical studies provide a possible direct probe of chirality by exploiting an enantiomer selective additional coupling involving magnetic-dipole, magnetic-field, and electric field operators. This offers a way for direct experimental detection of chirality by nuclear magneto-electric resonance (NMER). This method uses both resonant magnetic and electric radiofrequency (RF) fields. The weakness of the chiral interaction though requires a large electric RF field and a small transverse RF magnetic field over the sample volume, which is a non-trivial constraint. In this study, we present a detailed study of the NMER concept and a possible experimental realization based on a loop-gap resonator. For this original device, the basic principle and numerical studies as well as fabrication and measurements of the frequency dependence of the scattering parameter are reported. By simulating the NMER spin dynamics for our device and taking the 19F NMER signal of enantiomer-pure 1,1,1-trifluoropropan-2-ol, we predict a chirality induced NMER signal that accounts for 1%-5% of the standard achiral NMR signal.

  17. Electromagnetic coupling in a planar periodic configuration of resonators

    Directory of Open Access Journals (Sweden)

    C. Jouvaud

    2012-10-01

    Full Text Available We are studying arrays composed of a periodic arrangement of sub-wavelength resonators. An analytical model is developed inside an array of 4 by 4 multi-gap split ring resonators. To describe the frequency splitting of the single fundamental resonance, we propose a simple model based on the approximation of each resonator as an electrical dipole and a magnetic dipole that are driven by the same complex amplitude. We show that the relative strength of the two dipoles strongly depends on cell symmetry. With this approximation, the dispersion relation can be obtained for an infinite size array. A simple matrix diagonalization provides a powerful way to deduce the resonant frequencies for finite size array. These results are comforted by numerical simulations. Finally, an experimental demonstration of a tunable antenna based on this study is presented.

  18. Tuning Fano resonances with a nano-chamber of air.

    Science.gov (United States)

    Chen, Jianjun; He, Keke; Sun, Chengwei; Wang, Yujia; Li, Hongyun; Gong, Qihuang

    2016-05-15

    By designing a polymer-film-coated asymmetric metallic slit structure that only contains one nanocavity side-coupled with a subwavelength plasmonic waveguide, the Fano resonance is realized in the experiment. The Fano resonance originates from the interference between the narrow resonant spectra of the radiative light from the nanocavity and the broad nonresonant spectra of the directly transmitted light from the slit. The lateral dimension of the asymmetric slit is only 825 nm. Due to the presence of the soft polymer film, a nano-chamber of air is constructed. Based on the opto-thermal effect, the air volume in the nano-chamber is expanded by a laser beam, which blueshifts the Fano resonance. This tunable Fano resonance in such a submicron slit structure with a nano-chamber is of importance in the highly integrated plasmonic circuits. PMID:27176948

  19. Diphoton Resonance from a Warped Extra Dimension

    CERN Document Server

    Bauer, Martin; Neubert, Matthias

    2016-01-01

    We argue that extensions of the Standard Model (SM) with a warped extra dimension, which successfully address the hierarchy and flavor problems of elementary particle physics, can provide an elegant explanation of the 750 GeV diphoton excess recently reported by ATLAS and CMS. A gauge-singlet bulk scalar with O(1) couplings to fermions is identified as the new resonance S, and the vector-like Kaluza-Klein excitations of the SM quarks and leptons mediate its loop-induced couplings to photons and gluons. The electroweak gauge symmetry almost unambiguously dictates the bulk matter content and hence the hierarchies of the S->\\gamma\\gamma, WW, ZZ, Z\\gamma, t\\bar t and dijet decay rates. We find that the S->Z\\gamma decay mode is strongly suppressed, such that Br(S->Z\\gamma)Br(S->\\gamma\\gamma)S->\\gamma\\gamma signal requires Kaluza-Klein masses in the multi-TeV range, in perfect agreement with bounds from flavor physics and electroweak precision observables.

  20. Classical decoherence in a nanomechanical resonator

    Science.gov (United States)

    Maillet, O.; Vavrek, F.; Fefferman, A. D.; Bourgeois, O.; Collin, E.

    2016-07-01

    Decoherence is an essential mechanism that defines the boundary between classical and quantum behaviours, while imposing technological bounds for quantum devices. Little is known about quantum coherence of mechanical systems, as opposed to electromagnetic degrees of freedom. But decoherence can also be thought of in a purely classical context, as the loss of phase coherence in the classical phase space. Indeed the bridge between quantum and classical physics is under intense investigation, using, in particular, classical nanomechanical analogues of quantum phenomena. In the present work, by separating pure dephasing from dissipation, we quantitatively model the classical decoherence of a mechanical resonator: through the experimental control of frequency fluctuations, we engineer artificial dephasing. Building on the fruitful analogy introduced between spins/quantum bits and nanomechanical modes, we report on the methods available to define pure dephasing in these systems, while demonstrating the intrinsic almost-ideal properties of silicon nitride beams. These experimental and theoretical results, at the boundary between classical nanomechanics and quantum information fields, are prerequisite in the understanding of decoherence processes in mechanical devices, both classical and quantum.

  1. Squeezing of light via reflection from a silicon micromechanical resonator

    CERN Document Server

    Safavi-Naeini, Amir H; Hill, Jeff T; Chan, Jasper; Aspelmeyer, Markus; Painter, Oskar

    2013-01-01

    We present the measurement of squeezed light generation using an engineered optomechanical system fabricated from a silicon microchip and composed of a micromechanical resonator coupled to a nanophotonic cavity. Laser light is used to measure the fluctuations in the position of the mechanical resonator at a measurement rate comparable to the free dynamics of the mechanical resonator, and greater than its thermal decoherence rate. By approaching the strong continuous measurement regime we observe, through homodyne detection, non-trivial modifications of the reflected light's vacuum fluctuation spectrum. In spite of the mechanical resonator's highly excited thermal state ($10,000$ phonons), we observe squeezing at the level of $4.5 \\pm 0.5%$ below that of shot-noise over a few MHz bandwidth around the mechanical resonance frequency of 28 MHz. This squeezing is interpreted as an unambiguous quantum signature of radiation pressure shot-noise.

  2. RCCS operation with a resonant frequency error in the KOMAC

    Science.gov (United States)

    Seo, Dong-Hyuk

    2015-10-01

    The resonance control cooling systems (RCCSs) of the Korea Multi-purpose Accelerator Complex have been operated for cooling the drift tubes (DT) and controlling the resonant frequency of the drift tube linac (DTL). The DTL should maintain a resonant frequency of 350 MHz during operation. A RCCS can control the temperature of the cooling water to within ±0.1 °C by using a 3-way valve opening and has a constant-cooling-water-temperature control mode and resonant-frequency-control mode. In the case of the resonant-frequency control, the error in the frequency is measured by using the low-level radio-frequency control system, and the RCCS uses a proportional-integral-derivative control algorithm to compensate for the error by controlling the temperature of the cooling water to the DT.

  3. Phase Matching of Diverse Modes in a WGM Resonator

    Science.gov (United States)

    Savchenkov, Anatoliy; Strekalov, Dmitry; Yu, Nan; Matsko, Andrey; Mohageg, Makan; Maleki, Lute

    2008-01-01

    Phase matching of diverse electromagnetic modes (specifically, coexisting optical and microwave modes) in a whispering-gallery-mode (WGM) resonator has been predicted theoretically and verified experimentally. Such phase matching is necessary for storage of microwave/terahertz and optical electromagnetic energy in the same resonator, as needed for exploitation of nonlinear optical phenomena. WGM resonators are used in research on nonlinear optical phenomena at low optical intensities and as a basis for design and fabrication of novel optical devices. Examples of nonlinear optical phenomena recently demonstrated in WGM resonators include low-threshold Raman lasing, optomechanical oscillations, frequency doubling, and hyperparametric oscillations. The present findings regarding phase matching were made in research on low-threshold, strongly nondegenerate parametric oscillations in lithium niobate WGM resonators. The principle of operation of such an oscillator is rooted in two previously observed phenomena: (1) stimulated Raman scattering by polaritons in lithium niobate and (2) phase matching of nonlinear optical processes via geometrical confinement of light. The oscillator is partly similar to terahertz oscillators based on lithium niobate crystals, the key difference being that a novel geometrical configuration of this oscillator supports oscillation in the regime. The high resonance quality factors (Q values) typical of WGM resonators make it possible to achieve oscillation at a threshold signal level much lower than that in a non-WGM-resonator lithium niobate crystal.

  4. Resonance Photon Generation in a Vibrating Cavity

    CERN Document Server

    Dodonov, V V

    1998-01-01

    The problem of photon creation from vacuum due to the nonstationary Casimir effect in an ideal one-dimensional Fabry--Perot cavity with vibrating walls is solved in the resonance case, when the frequency of vibrations is close to the frequency of some unperturbed electromagnetic mode: $\\omega_w=p(\\pi c/L_0)(1+\\delta)$, $|\\delta|\\ll 1$, (p=1,2,...). An explicit analytical expression for the total energy in all the modes shows an exponential growth if $|\\delta|$ is less than the dimensionless amplitude of vibrations $\\epsilon\\ll 1$, the increment being proportional to $p\\sqrt{\\epsilon^2-\\delta^2}$. The rate of photon generation from vacuum in the (j+ps)th mode goes asymptotically to a constant value $cp^2\\sin^2(\\pi j/p)\\sqrt{\\epsilon^2-\\delta^2}/[\\pi L_0 (j+ps)]$, the numbers of photons in the modes with indices p,2p,3p,... being the integrals of motion. The total number of photons in all the modes is proportional to $p^3(\\epsilon^2-\\delta^2) t^2$ in the short-time and in the long-time limits. In the case of st...

  5. Photonic crystal resonator integrated in a microfluidic system

    DEFF Research Database (Denmark)

    Rodrigues de Sousa Nunes, Pedro André; Mortensen, Niels Asger; Kutter, Jörg Peter;

    2008-01-01

    -free refractive index detection. The resonator was fabricated in a silicon oxynitride platform, to support electro-osmotic flow, and operated at =1.55 m. Different aqueous solutions of ethanol with refractive indices ranging from n1.3330 to 1.3616 were pumped into the column/resonator, and the transmission...

  6. A comparison of approaches to estimate the resonance energy

    NARCIS (Netherlands)

    Zielinski, Marcin; Havenith, Remco W. A.; Jenneskens, Leonardus W.; van Lenthe, Joop H.

    2010-01-01

    We discuss Ab Initio approaches to calculate the energy lowering (stabilisation) due to aromaticity. We compare the valence bond method and the block-localised wave function approaches to calculate the resonance energy. We conclude that the valence bond approach employs a Pauling-Wheland resonance e

  7. Optimized coplanar waveguide resonators for a superconductor-atom interface

    Science.gov (United States)

    Beck, M. A.; Isaacs, J. A.; Booth, D.; Pritchard, J. D.; Saffman, M.; McDermott, R.

    2016-08-01

    We describe the design and characterization of superconducting coplanar waveguide cavities tailored to facilitate strong coupling between superconducting quantum circuits and single trapped Rydberg atoms. For initial superconductor-atom experiments at 4.2 K, we show that resonator quality factors above 104 can be readily achieved. Furthermore, we demonstrate that the incorporation of thick-film copper electrodes at a voltage antinode of the resonator provides a route to enhance the zero-point electric fields of the resonator in a trapping region that is 40 μm above the chip surface, thereby minimizing chip heating from scattered trap light. The combination of high resonator quality factor and strong electric dipole coupling between the resonator and the atom should make it possible to achieve the strong coupling limit of cavity quantum electrodynamics with this system.

  8. Optimized Coplanar Waveguide Resonators for a Superconductor-Atom Interface

    CERN Document Server

    Beck, M A; Booth, D; Pritchard, J D; Saffman, M; McDermott, R

    2016-01-01

    We describe the design and characterization of superconducting coplanar waveguide cavities tailored to facilitate strong coupling between superconducting quantum circuits and single trapped Rydberg atoms. For initial superconductor-atom experiments at 4.2 K, we show that resonator quality factors above $10^4$ can be readily achieved. Furthermore, we demonstrate that the incorporation of thick-film copper electrodes at a voltage antinode of the resonator provides a route to enhance the zero-point electric fields of the resonator in a trapping region that is 40 $\\mu$m above the chip surface, thereby minimizing chip heating from scattered trap light. The combination of high resonator quality factor and strong electric dipole coupling between the resonator and the atom should make it possible to achieve the strong coupling limit of cavity quantum electrodynamics with this system.

  9. Dispersive Thermometry with a Josephson Junction Coupled to a Resonator

    Science.gov (United States)

    Saira, O.-P.; Zgirski, M.; Viisanen, K. L.; Golubev, D. S.; Pekola, J. P.

    2016-08-01

    We embed a small Josephson junction in a microwave resonator that allows simultaneous dc biasing and dispersive readout. Thermal fluctuations drive the junction into phase diffusion and induce a temperature-dependent shift in the resonance frequency. By sensing the thermal noise of a remote resistor in this manner, we demonstrate primary thermometry in the range of 300 mK to below 100 mK, and high-bandwidth (7.5 MHz) operation with a noise-equivalent temperature of better than 10 μ K /√{Hz } . At a finite bias voltage close to a Fiske resonance, amplification of the microwave probe signal is observed. We develop an accurate theoretical model of our device based on the theory of dynamical Coulomb blockade.

  10. Resonance frequencies of a cavity containing a compressible viscous fluid

    Science.gov (United States)

    Conca, C.; Planchard, J.; Vanninathan, M.

    1993-03-01

    The aim of this paper is to study the resonance spectrum of a cavity containing a compressible viscous fluid. This system admits a discrete infinite sequence of eigenvalues whose real parts are negative, which is interpreted as the damping effect introduced by viscosity. Only a finite number of them have non-zero imaginary parts and this number depends on viscosity; a simple criterion is given for their position in the complex plane. The case of a cavity containing an elastic mechanical system immersed in the fluid is also examined; from a qualitative point of view, the nature of the resonance spectrum remains unchanged.

  11. A microwave resonator for limiting depth sensitivity for electron paramagnetic resonance spectroscopy of surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Sidabras, Jason W.; Varanasi, Shiv K.; Hyde, James S. [Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin 53211 (United States); Mett, Richard R. [Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin 53211 (United States); Department of Physics and Chemistry, Milwaukee School of Engineering, Milwaukee, Wisconsin 53202 (United States); Swarts, Steven G. [Department of Radiation Oncology, University of Florida, Gainesville, Florida, 32610 (United States); Swartz, Harold M. [Department of Radiology, Geisel Medical School at Dartmouth, Hanover, New Hampshire 03755 (United States)

    2014-10-15

    A microwave Surface Resonator Array (SRA) structure is described for use in Electron Paramagnetic Resonance (EPR) spectroscopy. The SRA has a series of anti-parallel transmission line modes that provides a region of sensitivity equal to the cross-sectional area times its depth sensitivity, which is approximately half the distance between the transmission line centers. It is shown that the quarter-wave twin-lead transmission line can be a useful element for design of microwave resonators at frequencies as high as 10 GHz. The SRA geometry is presented as a novel resonator for use in surface spectroscopy where the region of interest is either surrounded by lossy material, or the spectroscopist wishes to minimize signal from surrounding materials. One such application is in vivo spectroscopy of human finger-nails at X-band (9.5 GHz) to measure ionizing radiation dosages. In order to reduce losses associated with tissues beneath the nail that yield no EPR signal, the SRA structure is designed to limit depth sensitivity to the thickness of the fingernail. Another application, due to the resonator geometry and limited depth penetration, is surface spectroscopy in coating or material science. To test this application, a spectrum of 1.44 μM of Mg{sup 2+} doped polystyrene 1.1 mm thick on an aluminum surface is obtained. Modeling, design, and simulations were performed using Wolfram Mathematica (Champaign, IL; v. 9.0) and Ansys High Frequency Structure Simulator (HFSS; Canonsburg, PA; v. 15.0). A micro-strip coupling circuit is designed to suppress unwanted modes and provide a balanced impedance transformation to a 50 Ω coaxial input. Agreement between simulated and experimental results is shown.

  12. A microwave resonator for limiting depth sensitivity for electron paramagnetic resonance spectroscopy of surfaces

    Science.gov (United States)

    Sidabras, Jason W.; Varanasi, Shiv K.; Mett, Richard R.; Swarts, Steven G.; Swartz, Harold M.; Hyde, James S.

    2014-10-01

    A microwave Surface Resonator Array (SRA) structure is described for use in Electron Paramagnetic Resonance (EPR) spectroscopy. The SRA has a series of anti-parallel transmission line modes that provides a region of sensitivity equal to the cross-sectional area times its depth sensitivity, which is approximately half the distance between the transmission line centers. It is shown that the quarter-wave twin-lead transmission line can be a useful element for design of microwave resonators at frequencies as high as 10 GHz. The SRA geometry is presented as a novel resonator for use in surface spectroscopy where the region of interest is either surrounded by lossy material, or the spectroscopist wishes to minimize signal from surrounding materials. One such application is in vivo spectroscopy of human finger-nails at X-band (9.5 GHz) to measure ionizing radiation dosages. In order to reduce losses associated with tissues beneath the nail that yield no EPR signal, the SRA structure is designed to limit depth sensitivity to the thickness of the fingernail. Another application, due to the resonator geometry and limited depth penetration, is surface spectroscopy in coating or material science. To test this application, a spectrum of 1.44 μM of Mg2+ doped polystyrene 1.1 mm thick on an aluminum surface is obtained. Modeling, design, and simulations were performed using Wolfram Mathematica (Champaign, IL; v. 9.0) and Ansys High Frequency Structure Simulator (HFSS; Canonsburg, PA; v. 15.0). A micro-strip coupling circuit is designed to suppress unwanted modes and provide a balanced impedance transformation to a 50 Ω coaxial input. Agreement between simulated and experimental results is shown.

  13. Tunable resonant transmission of electromagnetic waves through a magnetized plasma.

    Science.gov (United States)

    Kee, Chul-Sik; Li, Shou-Zhe; Kim, Kihong; Lim, H

    2003-03-01

    We theoretically investigate the resonant transmission of circularly polarized electromagnetic waves in the electromagnetic stop band of a magnetized plasma slab using the invariant embedding method. The frequency and quality factor of the resonant mode for the right-handed (left-handed) circularly polarized wave created by inserting a dielectric layer into the plasma increase (decrease) as the magnitude of the external magnetic field increases. These phenomena are compared with the characteristics of resonant modes in metallic and dielectric Fabry-Perot resonators to show that they are due to the change of plasma reflectivity. We also discuss the damping effect due to the collisions of the constituent particles of the plasma on the resonant transmission of circularly polarized waves. PMID:12689184

  14. Magnetic resonance spectroscopy as a diagnostic modality for carcinoma thyroid

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Nikhil [Department of Surgery, Maulana Azad Medical College, Lok Nayak Hospital, New Delhi (India)], E-mail: nikhil_ms26@yahoo.co.in; Kakar, Arun K. [Department of Surgery, Maulana Azad Medical College, Lok Nayak Hospital, New Delhi (India); Chowdhury, Veena [Department of Radiodiagnosis, Maulana Azad Medical College, Lok Nayak Hospital, New Delhi (India); Gulati, Praveen [MR Centre, A-23 Green Park, New Delhi (India); Shankar, L. Ravi [Department of Radioiodine Uptake and Imaging, Institute of Nucler Medicine and Allied Sciences (INMAS), Timarpur, New Delhi (India); Vindal, Anubhav [Department of Surgery, Maulana Azad Medical College, Lok Nayak Hospital, New Delhi (India)

    2007-12-15

    Aim: The aim of this study was to observe the findings of magnetic resonance spectroscopy of solitary thyroid nodules and its correlation with histopathology. Materials and methods: In this study, magnetic resonance spectroscopy was carried out on 26 patients having solitary thyroid nodules. Magnetic resonance spectroscopy (MRS) was performed on a 1.5 T super conductive system with gradient strength of 33 mTs. Fine needle aspiration cytology was done after MRS. All 26 patients underwent surgery either because of cytopathologically proven malignancy or because of cosmetic reasons. Findings of magnetic resonance spectroscopy were compared with histopathology of thyroid specimens. Results and conclusion: It was seen that presence or absence of choline peak correlates very well with presence or absence of malignant foci with in the nodule (sensitivity = 100%; specificity = 88.88%). These results indicate that magnetic resonance spectroscopy may prove to be an useful diagnostic modality for carcinoma thyroid.

  15. Two-resonator circuit QED: A superconducting quantum switch

    International Nuclear Information System (INIS)

    Coupling different kind of superconducting (sc) qubits to on-chip microwave resonators has strongly advanced the field of circuit QED. Regarding the application of circuit QED systems in quantum information processing it would be highly desirable to switch on and off the interaction between two resonators. We introduce a formalism for two-resonator circuit QED where two on-chip microwave resonators are simultaneously coupled to one sc qubit. In this three-circuit network, the qubit mediates a geometric and a dynamic second-order interaction between the two resonators. These two coupling strengths can be tuned to be equal by varying the qubit operation point, thus permitting to switch on and off the interaction between the resonators. We discuss the effect of the qubit on the dynamic second-order coupling and how it can be deliberately manipulated to realize a sc quantum switch. Finally, we present a realistic design for implementing a two-resonator circuit QED setup based on a flux qubit and show preliminary experimental results.

  16. Center mode of a doubly resonant optical periodic structure

    Science.gov (United States)

    Alagappan, G.; Png, C. E.

    2016-07-01

    An optical periodic structure with a single spatial resonance exhibits a stopband. When a second spatial resonance very close to the first one is added, the resulting doubly resonant structure exhibits a Gaussian enveloped, high quality factor transmission state right at the center of the original stopband. Using a slowly varying envelope approximation, we describe the optical characteristics of this transmission state analytically. The transmission state exists despite an optical structure of low refractive index contrast, and has potential applications in nano-optics, and photonics.

  17. Easy fabrication of a tunable high-pass birdcage resonator.

    Science.gov (United States)

    Xu, Y; Tang, P

    1997-07-01

    A practical design for a high-pass birdcage resonator is presented. Precision seamless telescoping tubes were used for easy tuning of resonant frequency by adjusting the length of the coils. Three probes, of 4.4, 5.0, and 25.0 cm in diameter, respectively, were constructed and tested. An empirical formula is given that can be used to calculate the capacitance needed for a given frequency when the desired physical dimension and the number of elements of the coll are specified. A simple three-step procedure is suggested for easy fabrication of resonators that are routinely tunable over tens of megahertz. PMID:9211393

  18. A NOTE ON THE NARROW OPEN CHANNEL RESONANCE

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A narrow open channel resonant phenomenon, newly found by the authors in corresponding numerical calculations, was proved to exist based on the method of matching asymptotic expansions for three different channel configurations. It is shown that the resonant wave number k emerges around kL=nπ, n=1,2,3,…∞ with a corresponding frequency shift, where L is the length of the channel. It is also clear that the resonance in a narrow open channel is an essential property of a channel as long as it is uniformly narrow.

  19. A resonant chain of four transiting, sub-Neptune planets.

    Science.gov (United States)

    Mills, Sean M; Fabrycky, Daniel C; Migaszewski, Cezary; Ford, Eric B; Petigura, Erik; Isaacson, Howard

    2016-05-26

    Surveys have revealed many multi-planet systems containing super-Earths and Neptunes in orbits of a few days to a few months. There is debate whether in situ assembly or inward migration is the dominant mechanism of the formation of such planetary systems. Simulations suggest that migration creates tightly packed systems with planets whose orbital periods may be expressed as ratios of small integers (resonances), often in a many-planet series (chain). In the hundreds of multi-planet systems of sub-Neptunes, more planet pairs are observed near resonances than would generally be expected, but no individual system has hitherto been identified that must have been formed by migration. Proximity to resonance enables the detection of planets perturbing each other. Here we report transit timing variations of the four planets in the Kepler-223 system, model these variations as resonant-angle librations, and compute the long-term stability of the resonant chain. The architecture of Kepler-223 is too finely tuned to have been formed by scattering, and our numerical simulations demonstrate that its properties are natural outcomes of the migration hypothesis. Similar systems could be destabilized by any of several mechanisms, contributing to the observed orbital-period distribution, where many planets are not in resonances. Planetesimal interactions in particular are thought to be responsible for establishing the current orbits of the four giant planets in the Solar System by disrupting a theoretical initial resonant chain similar to that observed in Kepler-223. PMID:27225123

  20. Resonant cancellation of off-resonant effects in a multilevel qubit

    CERN Document Server

    Tian, L; Tian, Lin; Lloyd, Seth

    2000-01-01

    Off-resonant effects are a significant source of error in quantumcomputation. This paper presents a group theoretic proof that off-resonanttransitions to the higher levels of a multilevel qubit can be completelyprevented in principle. This result can be generalized to prevent unwantedtransitions due to qubit-qubit interactions. A simple scheme exploiting dynamicpulse control techniques is presented that can cancel transitions to higherstates to arbitrary accuracy.

  1. Coherent stochastic resonance in the presence of a field

    Science.gov (United States)

    Gitterman, Moshe; Weiss, George H.

    1995-11-01

    A recent paper by Bulsara, Lowen, and Rees [Phys. Rev. E 49, 4989 (1994)] presents a perturbation analysis of coherent stochastic resonance in a half-space in the presence of a field. We believe that the analysis there was flawed due to an improper use of the method of images and that a correct version of a perturbation analysis can be given by using a transformation of the underlying equations. The result still exhibits stochastic resonance.

  2. Optical combs with a crystalline whispering gallery mode resonator

    CERN Document Server

    Savchenkov, Anatoliy A; Ilchenko, Vladimir S; Solomatine, Iouri; Seidel, David; Maleki, Lute

    2008-01-01

    We report on the experimental demonstration of a tunable monolithic optical frequency comb generator. The device is based on the four-wave mixing in a crystalline calcium fluoride whispering gallery mode resonator. The frequency spacing of the comb is given by an integer number of the free spectral range of the resonator. We select the desired number by tuning the pumping laser frequency with respect to the corresponding resonator mode. We also observe interacting optical combs and high-frequency hyperparametric oscillation, depending on the experimental conditions. A potential application of the comb for generating narrowband frequency microwave signals is demonstrated.

  3. Chemisorption-Induced Resonance Frequency Shift of a Microcantilever

    International Nuclear Information System (INIS)

    The autonomy and property of atoms/molecules adsorbed on the surface of a microcantilever can be probed by measuring its resonance frequency shift due to adsorption. The resonance frequency change of a cantilever induced by chemisorption is theoretically studied. Oxygen chemisorbed on the Si(100) surface is taken as a representative example. We demonstrate that the resonant response of the cantilever is mainly determined by the chemisorption-induced bending stiffness variation, which depends on the bond configurations formed by the adsorbed atoms and substrate atoms. This study is helpful for optimal design of microcantilever-based sensors for various applications. (condensed matter: structure, mechanical and thermal properties)

  4. A XOR Threshold Logic Implementation Through Resonant Tunneling Diode

    Directory of Open Access Journals (Sweden)

    Nitesh Kumar Dixit

    2012-10-01

    Full Text Available Resonant tunneling diodes (RTDs have functional versatility and high speed switching capability. The integration of resonant tunneling diodes and MOS transistor makes threshold gates and logics. The design and fabrication of linear threshold gates will be presented based on a mono stable bis table transition logic element. Each of its input terminals consist out of a resonant tunnelling diode merged with a transistor device. The circuit models of RTD and MOSFET are simulated in HSPICE. Two input XOR gate is designed and tested.

  5. A XOR Threshold Logic Implementation Through Resonant Tunneling Diode

    Directory of Open Access Journals (Sweden)

    Nitesh Kumar Dixit

    2012-11-01

    Full Text Available Resonant tunneling diodes (RTDs have functional versatility and high speed switching capability. The integration of resonant tunneling diodes and MOS transistor makes threshold gates and logics. The design and fabrication of linear threshold gates will be presented based on a monostable bistable transition logic element. Each of its input terminals consist out of a resonant tunnelling diode merged with a transistor device. The circuit models of RTD and MOSFET are simulated in HSPICE. Two input XOR gate is designed and tested.

  6. Simulation of pyroshock environments using a tunable resonant fixture

    Energy Technology Data Exchange (ETDEWEB)

    Davie, N.T.

    1993-09-30

    Disclosed are a method and apparatus for simulating pyrotechnic shock for the purpose of qualifying electronic components for use in weapons, satellite, and aerospace applications. According to the invention, a single resonant bar fixture has an adjustable resonant frequency in order to exhibit a desired shock response spectrum upon mechanical impact. The invention eliminates the need for availability of a large number of different fixtures, capable of exhibiting a range of shock response characteristics, in favor of a single tunable system.

  7. Simulation of pyroshock environments using a tunable resonant fixture

    Energy Technology Data Exchange (ETDEWEB)

    Davie, N.T.

    1996-10-15

    Disclosed are a method and apparatus for simulating pyrotechnic shock for the purpose of qualifying electronic components for use in weapons, satellite, and aerospace applications. According to the invention, a single resonant bar fixture has an adjustable resonant frequency in order to exhibit a desired shock response spectrum upon mechanical impact. The invention eliminates the need for availability of a large number of different fixtures, capable of exhibiting a range of shock response characteristics, in favor of a single tunable system. 32 figs.

  8. Simulation of pyroshock environments using a tunable resonant fixture

    Energy Technology Data Exchange (ETDEWEB)

    Davie, Neil T. (Cedar Crest, NM)

    1996-01-01

    Disclosed are a method and apparatus for simulating pyrotechnic shock for the purpose of qualifying electronic components for use in weapons, satellite, and aerospace applications. According to the invention, a single resonant bar fixture has an adjustable resonant frequency in order to exhibit a desired shock response spectrum upon mechanical impact. The invention eliminates the need for availability of a large number of different fixtures, capable of exhibiting a range of shock response characteristics, in favor of a single tunable system.

  9. A Search for ttbar Resonances with the ATLAS Detector

    CERN Multimedia

    Livermore, SSA

    2012-01-01

    A search for resonant production of ttbar pairs with data collected in 2011 by ATLAS. The analyses presented here concentrate on the lepton + jets and fully leptonic final states, with datasets corresponding to a total integrated luminosity of 2.05 and 1.04 fb-1 respectively. Limits are set on the production cross-section times branching ratio to top quark pairs of resonances predicted by key benchmark models. Prospects are also presented for an analysis tailored to the search for high mass resonances which decay to pairs of "boosted" top quarks with large transverse momenta.

  10. A Compact Dual Band Dielectric Resonator Antenna For Wireless Applications

    Directory of Open Access Journals (Sweden)

    A. Gharsallah

    2013-06-01

    Full Text Available This paper presents the design of a dual band rectangular Dielectric Resonator Antenna (DRAcoupled to narrow slot aperture that is fed by microstrip line. The fundamental TE111mode andhigher-order TE113mode are excited with their resonant frequencies respectively. Thesefrequencies can be controlled by changing the DRA dimensions. A dielectric resonator with highpermittivity is used to miniaturize the global structure. The proposed antenna is designed to havedual band operation suitable for both DCS (1710 - 1880 MHz and WLAN (2400 - 2484 MHzapplications. The return loss, radiation pattern and gain of the proposed antenna are evaluated.Reasonable agreement between simulation and experimental results is obtained.

  11. Optical Fiber Excitation of Fano Resonances in a Silicon Microsphere

    Science.gov (United States)

    Sabahattin Gökay, Ulaş; Zakwan, Muhammad; Demir, Abdullah; Serpengüzel, Ali

    2016-01-01

    In this article, Fano lineshape whispering gallery modes were observed in the light scattering spectrum of a silicon microsphere in near-infrared telecommunication wavelengths. A simple model is presented to explain the transition from Lorentzian lineshape to the Fano lineshape resonances with the coupled-mode theory of multiple whispering gallery modes. Polar mode spacing of 0.23 nm is observed in the spectra, which correlates well with the calculated value. The quality factor of the Lorentzian and Fano resonances are on the order of 105. By using an appropriate interface design for the microsphere coupling geometries, Fano lineshape optical resonances herald novel device applications for silicon volumetric lightwave circuits.

  12. Optical modulation in a resonant tunneling relaxation oscillator

    OpenAIRE

    Figueiredo, J.M.L.; Stanley, C.R.; Boyd, A.R.; Ironside, C. N.; McMeekin, S.G.; Leite, A. M. P.

    1999-01-01

    We report high-speed optical modulation in a resonant tunneling relaxation oscillator consisting of a resonant tunneling diode (RTD) integrated with a unipolar optical waveguide and incorporated in a package with a coplanar waveguide transmission line. When appropriately biased, the RTD can provide wide-bandwidth electrical gain. For wavelengths near the material band edge, small changes of the applied voltage give rise to large, high-speed electroabsorption modulation of the light. We have o...

  13. Optical modulation in a resonant tunneling relaxation oscillator

    OpenAIRE

    Figueiredo, J.M.L.; Stanley, C.R.; Boyd, A.R.; Ironside, C. N.

    2005-01-01

    We report high speed optical modulation in a resonant tunneling relaxation oscillator consisting of a resonant tunneling diode (RTD) integrated with a unipolar optical waveguide and incorporated in a package with a coplanar waveguide transmission line. When appropriately biased, the RTD can provide wide-bandwidth electrical gain. For wavelengths near the material band-edge, small changes of the applied voltage give rise to large, high-speed electro-absorption modulation of the light. We have ...

  14. Modeling of a Resonant Tunneling Diode Optical Modulator

    OpenAIRE

    Calado, J. J. N.; Figueiredo, J.M.L.; Ironside, C. N.

    2005-01-01

    The integration of a double barrier resonant tunneling diode within a unipolar optical waveguide provides electrical gain over a wide bandwidth. Due to the non-linearities introduced by the double barrier resonant tunneling diode an unipolar InGaAlAs/InP optical waveguide can be employed both as optical modulator and optical detector. The modeling results of a device operating as optical modulator agree with preliminary experimental data, foreseeing for an optimized device modulation depths u...

  15. Parameter-induced stochastic resonance with a periodic signal

    Institute of Scientific and Technical Information of China (English)

    Li Jian-Long; Xu Bo-Hou

    2006-01-01

    In this paper conventional stochastic resonance (CSR) is realized by adding the noise intensity. This demonstrates that tuning the system parameters with fixed noise can make the noise play a constructive role and realize parameterinduced stochastic resonance (PSR). PSR can be interpreted as changing the intrinsic characteristic of the dynamical system to yield the cooperative effect between the stochastic-subjected nonlinear system and the external periodic force. This can be realized at any noise intensity, which greatly differs from CSR that is realized under the condition of the initial noise intensity not greater than the resonance level. Moreover, it is proved that PSR is different from the optimization of system parameters.

  16. Analysis of a Precambrian resonance-stabilized day length

    Science.gov (United States)

    Bartlett, Benjamin C.; Stevenson, David J.

    2016-06-01

    During the Precambrian era, Earth's decelerating rotation would have passed a 21 h period that would have been resonant with the semidiurnal atmospheric thermal tide. Near this point, the atmospheric torque would have been maximized, being comparable in magnitude but opposite in direction to the lunar torque, halting Earth's rotational deceleration, maintaining a constant day length, as detailed by Zahnle and Walker (1987). We develop a computational model to determine necessary conditions for formation and breakage of this resonant effect. Our simulations show the resonance to be resilient to atmospheric thermal noise but suggest a sudden atmospheric temperature increase like the deglaciation period following a possible "snowball Earth" near the end of the Precambrian would break this resonance; the Marinoan and Sturtian glaciations seem the most likely candidates for this event. Our model provides a simulated day length over time that resembles existing paleorotational data, though further data are needed to verify this hypothesis.

  17. Experimental Verification of Predicted Oscillations Near a Spin Resonance

    Energy Technology Data Exchange (ETDEWEB)

    Morozov, V.S.; /Michigan U.; Chao, A.W.; /Michigan U. /SLAC; Krisch, A.D.; Leonova, M.A.; Raymond, R.S.; Sivers, D.W.; Wong, V.K.; /Michigan U.; Ganshvili, A.; /Julich, Forschungszentrum /Erlangen - Nuremberg U.; Gebel, R.; Lehrach, A.; Lorentz, B.; Maier, R.; Prasuhn, D.; Stockhorst, H.; Welsch, D.; /Julich, Forschungszentrum; Hinterberger, F.; Ulbrich, K.; /Bonn U., HISKP; Schnase, A.; /JAEA, Ibaraki; Stephenson, E.J.; /Indiana U., IUCF; Brantjes, N.P.M.; Onderwater, C.J.G.; /Groningen U.

    2011-12-06

    The Chao matrix formalism allows analytic calculations of a beam's polarization behavior inside a spin resonance. We recently tested its prediction of polarization oscillations occurring in a stored beam of polarized particles near a spin resonance. Using a 1.85?GeV/c polarized deuteron beam stored in COSY, we swept a new rf solenoid's frequency rather rapidly through 400 Hz during 100 ms, while varying the distance between the sweep's end frequency and the central frequency of an rf-induced spin resonance. Our measurements of the deuteron's polarization for sweeps ending near and inside the resonance agree with the Chao formalism's predicted oscillations.

  18. A Second Peak in Diphoton (or Diboson) Resonances

    CERN Document Server

    Carena, Marcela; Ismail, Ahmed; Low, Ian; Shah, Nausheen R; Wagner, Carlos E M

    2016-01-01

    A resonant diphoton peak can be explained by gluon fusion production of a new neutral scalar which subsequently decays into a pair of photons. Loop-induced couplings of the new scalar to gluons and photons should be mediated by particles carrying color and electric charge. We point out that, if the loop particles hadronize before decaying, their bound states will induce a second peak in the diphoton invariant mass spectrum near twice their mass. Using the recently reported 750 GeV excess as a benchmark, we discuss implications of this second peak for resonance searches at the LHC. The second peak could be present for resonances in the $gg$ and $Z\\gamma$ channels, or even in the $WW$ and $ZZ$ channels for a pseudo-scalar resonance, where the couplings are mediated by new loop particles.

  19. Single-electron Spin Resonance in a Quadruple Quantum Dot

    Science.gov (United States)

    Otsuka, Tomohiro; Nakajima, Takashi; Delbecq, Matthieu R.; Amaha, Shinichi; Yoneda, Jun; Takeda, Kenta; Allison, Giles; Ito, Takumi; Sugawara, Retsu; Noiri, Akito; Ludwig, Arne; Wieck, Andreas D.; Tarucha, Seigo

    2016-08-01

    Electron spins in semiconductor quantum dots are good candidates of quantum bits for quantum information processing. Basic operations of the qubit have been realized in recent years: initialization, manipulation of single spins, two qubit entanglement operations, and readout. Now it becomes crucial to demonstrate scalability of this architecture by conducting spin operations on a scaled up system. Here, we demonstrate single-electron spin resonance in a quadruple quantum dot. A few-electron quadruple quantum dot is formed within a magnetic field gradient created by a micro-magnet. We oscillate the wave functions of the electrons in the quantum dots by applying microwave voltages and this induces electron spin resonance. The resonance energies of the four quantum dots are slightly different because of the stray field created by the micro-magnet and therefore frequency-resolved addressable control of each electron spin resonance is possible.

  20. Magnetic resonance imaging appearance of hypertensive encephalopathy in a dog

    OpenAIRE

    Bowman, Chloe A; Witham, Adrian; Tyrrell, Dayle; Long, Sam N

    2015-01-01

    A 16-year-old female spayed English Staffordshire terrier was presented for evaluation of a 10-month history of intermittent myoclonic episodes, and a one weeks history of short episodes of altered mentation, ataxia and collapse. Magnetic resonance imaging identified subcortical oedema, predominately in the parietal and temporal lobes and multiple cerebral microbleeds. Serum biochemistry, indirect blood pressure measurements and magnetic resonance imaging abnormalities were consistent with hy...

  1. Tailoring Light-Matter Interaction with a Nanoscale Plasmon Resonator

    OpenAIRE

    de Leon, Nathalie Pulmones; Shields, Brendan John; Yu, Chun; Englund, Dirk E.; Akimov, Alexey; Lukin, Mikhail D.; Park, Hongkun

    2012-01-01

    We propose and demonstrate a new approach for achieving strong light-matter interactions with quantum emitters. Our approach makes use of a plasmon resonator composed of defect-free, highly crystalline silver nanowires surrounded by patterned dielectric distributed Bragg reflectors (DBRs). These resonators have an effective mode volume (Veff) two orders of magnitude below the diffraction limit and quality factor (Q) approaching 100, enabling enhancement of spontaneous emission rates by a fact...

  2. A comparison of approaches to estimate the resonance energy

    OpenAIRE

    Zielinski, M.L.; Havenith, R.W.A.; Jenneskens, L. W.; Lenthe, J.H. van

    2010-01-01

    We discuss Ab Initio approaches to calculate the energy lowering (stabilisation) due to aromaticity. We compare the valence bond method and the block-localised wave function approaches to calculate the resonance energy. We conclude that the valence bond approach employs a Pauling–Wheland resonance energy and that the block-localised approach employs a delocalisation criterion. The latter is shown to be more basis set dependent in a series of illustrative calculations.

  3. A silicon single-crystal cryogenic optical resonator

    CERN Document Server

    Wiens, Eugen; Ernsting, Ingo; Luckmann, Heiko; Rosowski, Ulrich; Nevsky, Alexander; Schiller, Stephan

    2014-01-01

    We report on the demonstration and characterization of a silicon optical resonator for laser frequency stabilization, operating in the deep cryogenic regime at temperatures as low as 1.5 K. Robust operation was achieved, with absolute frequency drift less than 20 Hz over 1 hour. This stability allowed sensitive measurements of the resonator thermal expansion coefficient ($\\alpha$). We found $\\alpha=4.6\\times10^{-13}$ ${\\rm K^{-1}}$ at 1.6 K. At 16.8 K $\\alpha$ vanishes, with a derivative equal to $-6\\times10^{-10}$ ${\\rm K}^{-2}$. The temperature of the resonator was stabilized to a level below 10 $\\mu$K for averaging times longer than 20 s. The sensitivity of the resonator frequency to a variation of the laser power was also studied. The corresponding sensitivities and the expected Brownian noise indicate that this system should enable frequency stabilization of lasers at the low-$10^{-17}$ level.

  4. Observation of optomechanical coupling in a microbottle resonator

    CERN Document Server

    Asano, Motoki; Chen, Weijian; Özdemir, Şahin Kaya; Ikuta, Rikizo; Imoto, Nobuyuki; Yang, Lan; Yamamoto, Takashi

    2016-01-01

    In this work, we report optomechanical coupling, resolved sidebands and phonon lasing in a solid-core microbottle resonator fabricated on a single mode optical fiber. Mechanical modes with quality factors (Q_m) as high as 1.57*10^4 and 1.45*10^4 were observed, respectively, at the mechanical frequencies f_m=33.7 MHz and f_m=58.9 MHz. The maximum f_m*Q_m~0.85*10^12 Hz is close to the theoretical lower bound of 6*10^12 Hz needed to overcome thermal decoherence for resolved-sideband cooling of mechanical motion at room temperature, suggesting microbottle resonators as a possible platform for this endeavor. In addition to optomechanical effects, scatter-induced mode splitting and ringing phenomena, which are typical for high-quality optical resonances, were also observed in a microbottle resonator.

  5. The localized surface plasmon resonances based on a Bragg reflector

    Science.gov (United States)

    Wang, Jie; Liu, Yumin; Yu, Zhongyuan; Ye, Chunwei; Lv, Hongbo; Shu, Changgan

    2014-09-01

    In this paper, we present the theoretical analysis on how the wavelength of the localized surface plasmon resonances of gold nanoparticle can lead shift for the resonance wavelength. In our results, we calculate the scattering cross-section, the absorption cross-section and the field enhancement due to the nanoparticle. Numerical simulation were done using the finite element method (FEM). The work that we do here is different from the previous work because we use the Bragg reflector as a substrate. The Bragg reflector has a property of high reflectivity in some certain frequency bandwidth because of its periodic structure. The coherence interference of the Bragg reflector contributes to the plasmon resonances and results in some special character for a wide variety application, from sensing to photovoltaic. The periodic number of the Bragg reflector substrate and shapes of the nanoparticles are also discussed that result in a shift of the resonance wavelength.

  6. Resonance fluorescence from a telecom-wavelength quantum dot

    CERN Document Server

    Al-Khuzheyri, R; Huwer, J; Santana, T S; Szymanska, J Skiba-; Felle, M; Ward, M B; Stevenson, R M; Farrer, I; Tanner, M G; Hadfield, R H; Ritchie, D A; Shields, A J; Gerardot, B D

    2016-01-01

    We report on resonance fluorescence from a single quantum dot emitting at telecom wavelengths. We perform high-resolution spectroscopy and observe the Mollow triplet in the Rabi regime--a hallmark of resonance fluorescence. The measured resonance-fluorescence spectra allow us to rule out pure dephasing as a significant decoherence mechanism in these quantum dots. Combined with numerical simulations, the experimental results provide robust characterisation of charge noise in the environment of the quantum dot. Resonant control of the quantum dot opens up new possibilities for on-demand generation of indistinguishable single photons at telecom wavelengths as well as quantum optics experiments and direct manipulation of solid-state qubits in telecom-wavelength quantum dots.

  7. A novel integrated synchronous rectifier for LLC resonant converter

    OpenAIRE

    Ho, Kwun-yuan, Godwin.; 賀觀元.

    2012-01-01

    There is ever-increasing demand in telecommunication system, data server and computer equipment for low voltage, high current power supply. LLC resonant converter is a good topology on primary side of the converter because it has soft switching and resonant conversion. However, the passive rectifier in the secondary side has high power dissipation. Synchronous rectifier is a popular method to reduce this rectification loss. Although there are many types of synchronous rectifier for PWM conve...

  8. A microprocessor-based multichannel subsensory stochastic resonance electrical stimulator.

    Science.gov (United States)

    Chang, Gwo-Ching

    2013-01-01

    Stochastic resonance electrical stimulation is a novel intervention which provides potential benefits for improving postural control ability in the elderly, those with diabetic neuropathy, and stroke patients. In this paper, a microprocessor-based subsensory white noise electrical stimulator for the applications of stochastic resonance stimulation is developed. The proposed stimulator provides four independent programmable stimulation channels with constant-current output, possesses linear voltage-to-current relationship, and has two types of stimulation modes, pulse amplitude and width modulation.

  9. Pluto and Charon: A Case of Precession-Orbit Resonance?

    Science.gov (United States)

    Rubincam, David Parry; Smith, David E. (Technical Monitor)

    2000-01-01

    Pluto may be the only known case of precession-orbit resonance in the solar system. The Pluto-Charon system orbits the Sun with a period of 1 Plutonian year, which is 250.8 Earth years. The observed parameters of the system are such that Charon may cause Pluto to precess with a period near 250.8 Earth years. This gives rise to two possible resonances, heretofore unrecognized. The first is due to Pluto's orbit being highly eccentric, giving solar torques on Charon with a period of 1 Plutonian year. Charon in turn drives Pluto near its precession period. Volatiles, which are expected to shuttle across Pluto's surface between equator and pole as Pluto's obliquity oscillates, might change the planet's dynamical flattening enough so that Pluto crosses the nearby resonance, forcing the planet's equatorial plane to depart from Charon's orbital plane. The mutual tilt can reach as much as 2 deg after integrating over 5.6 x 10(exp 6) years, depending upon how close Pluto is to the resonance and the supply of volatiles. The second resonance is due to the Sun's traveling above and below Charon's orbital plane; it has a period half that of the eccentricity resonance. Reaching this half-Plutonian year resonance requires a much larger but still theoretically possible amount of volatiles. In this case the departure of Charon from an equatorial orbit is about 1 deg after integrating for 5.6 x 10(exp 6) years. The calculations ignore libration and tidal friction. It is not presently known how large the mutual tilt can grow over the age of the solar system, but if it remains only a few degrees, then observing such small angles from a Pluto flyby mission would be difficult. It is not clear why the parameters of the Pluto-Charon system are so close to the eccentricity resonance.

  10. Symmetry Energy Constraints from Giant Resonances: A Theoretical Overview

    CERN Document Server

    Piekarewicz, J

    2013-01-01

    Giant resonances encapsulate the dynamic response of the nuclear ground state to external perturbations. As such, they offer a unique view of the nucleus that is often not accessible otherwise. Although interesting in their own right, giant resonances are also enormously valuable in providing stringent constraints on the equation of state of asymmetric matter. We this view in mind, we focus on two modes of excitation that are essential in reaching this goal: the isoscalar giant monopole resonance (GMR) and the isovector giant dipole resonance (GDR). GMR energies in heavy nuclei are sensitive to the symmetry energy because they probe the incompressibility of neutron-rich matter. Unfortunately, access to the symmetry energy is hindered by the relatively low neutron-proton asymmetry of stable nuclei. Thus, the measurement of GMR energies in exotic nuclei is strongly encouraged. In the case of the GDR, we find the electric dipole polarizability of paramount importance. Indeed, the electric dipole polarizability a...

  11. Signal amplification in a qubit-resonator system

    International Nuclear Information System (INIS)

    We study the dynamics of a qubit-resonator system, when the resonator is driven by two signals. The interaction of the qubit with the high-amplitude driving we consider in terms of the qubit dressed states. Interaction of the dressed qubit with the second probing signal can essentially change the amplitude of this signal. We calculate the transmission amplitude of the probe signal through the resonator as a function of the qubit energy and the driving frequency detuning. The regions of increase and attenuation of the transmitted signal are calculated and demonstrated graphically. We present the influence of the signal parameters on the value of the amplification, and discuss the values of the qubit-resonator system parameters for an optimal amplification and attenuation of the weak probe signal.

  12. Lifetime of resonant state in a spherical quantum dot

    Institute of Scientific and Technical Information of China (English)

    Li Chun-Lei; Xiao Jing-Lin

    2007-01-01

    This paper calculates the lifetime of resonant state and transmission probability of a single electron tunnelling in a spherical quantum dot (SQD) structure by using the transfer matrix technique. In the SQD, the electron is confined both transversally and longitudinally, the motion in the transverse and longitudinal directions is separated by using the adiabatic approximation theory. Meanwhile, the energy levels of the former are considered as the effective confining potential. The numerical calculations are carried out for the SQD consisting of GaAs/InAs material. The obtained results show that the bigger radius of the quantum dot not only leads significantly to the shifts of resonant peaks toward the low-energy region, but also causes the lengthening of the lifetime of resonant state. The lifetime of resonant state can be calculated from the uncertainty principle between the energy half width and lifetime.

  13. Measuring ac losses in superconducting cables using a resonant circuit:Resonant current experiment (RESCUE)

    DEFF Research Database (Denmark)

    Däumling, Manfred; Olsen, Søren Krüger; Rasmussen, Carsten;

    1998-01-01

    A simple way to obtain true ac losses with a resonant circuit containing a superconductor, using the decay of the circuit current, is described. For the measurement a capacitor is short circuited with a superconducting cable. Energy in the circuit is provided by either charging up the capacitors...... with a certain voltage, or letting a de flow in the superconductor. When the oscillations are started-either by opening a switch in case a de is flowing or by closing a switch to connect the charged capacitors with the superconductor-the current (via a Rogowski coil) or the voltage on the capacitor can...

  14. Resonantly Enhanced Emission from a Luminescent Nanostructured Waveguide

    Science.gov (United States)

    Inada, Yasuhisa; Hashiya, Akira; Nitta, Mitsuru; Tomita, Shogo; Tsujimoto, Akira; Suzuki, Masa-aki; Yamaki, Takeyuki; Hirasawa, Taku

    2016-01-01

    Controlling the characteristics of photon emission represents a significant challenge for both fundamental science and device technologies. Research on microcavities, photonic crystals, and plasmonic nanocavities has focused on controlling spontaneous emission by way of designing a resonant structure around the emitter to modify the local density of photonic states. In this work, we demonstrate resonantly enhanced emission using luminescent nanostructured waveguide resonance (LUNAR). Our concept is based on coupling between emitters in the luminescent waveguide and a resonant waveguide mode that interacts with a periodic nanostructure and hence outcouples via diffraction. We show that the enhancement of resonance emission can be controlled by tuning the design parameters. We also demonstrate that the enhanced emission is attributable to the accelerated spontaneous emission rate that increases the probability of photon emission in the resonant mode, accompanied by enhanced the local density of photonic states. This study demonstrates that nanostructured luminescent materials can be designed to exhibit functional and enhanced emission. We anticipate that our concept will be used to improve the performance of a variety of photonic and optical applications ranging from bio/chemical sensors to lighting, displays and projectors. PMID:27682993

  15. Investigation of a delayed feedback controller of MEMS resonators

    KAUST Repository

    Masri, Karim M.

    2013-08-04

    Controlling mechanical systems is an important branch of mechanical engineering. Several techniques have been used to control Microelectromechanical systems (MEMS) resonators. In this paper, we study the effect of a delayed feedback controller on stabilizing MEMS resonators. A delayed feedback velocity controller is implemented through modifying the parallel plate electrostatic force used to excite the resonator into motion. A nonlinear single degree of freedom model is used to simulate the resonator response. Long time integration is used first. Then, a finite deference technique to capture periodic motion combined with the Floquet theory is used to capture the stable and unstable periodic responses. We show that applying a suitable positive gain can stabilize the MEMS resonator near or inside the instability dynamic pull in band. We also study the stability of the resonator by tracking its basins of attraction while sweeping the controller gain and the frequency of excitations. For positive delayed gains, we notice significant enhancement in the safe area of the basins of attraction. Copyright © 2013 by ASME.

  16. A walk along the steep neutron resonance data evaluation path

    Energy Technology Data Exchange (ETDEWEB)

    Bouland, O. [CEA Cadarache (DEN/CAD/DER/SPRC/LEPh), Physics Studies Lab., 13 - Saint-Paul-lez-Durance (France). Dept. d' Etudes des Reacteurs

    2008-07-01

    This paper goes through some major steps of a 'resonance evaluator' work and in particular on actual tricky questions: the nature of the experimental data base, the life without R-matrix approximations, the external level gambling, the influence of level structures in observables other than cross sections, the puzzling unresolved resonance range and the disused average sub-threshold fission cross sections. (authors)

  17. Experimental observation of the shear Alfven resonance in a tokamak

    International Nuclear Information System (INIS)

    Experiments in Tokapole II have demonstrated the shear Alfven resonance in a tokamak by direct probe measurement of the wave magnetic field within the plasma. The resonance is driven by external antennas and is identified as radially localized enhancements of the poloidal wave magnetic field. The radial location agrees with calculations which include toroidicity and noncircularity of the plasma cross-section. Other properties such as polarization, radial width, risetime, and wave enhancement also agree with MHD theory

  18. Longitudinal mode structure in a non-planar ring resonator

    Directory of Open Access Journals (Sweden)

    M Jaberi

    2013-09-01

    Full Text Available  The structure of longitudinal modes of a passively Q-switched, non-planar unidirectional ring-resonator,with Nd:YAG active medium is described in this article. Two different techniques are used to study the longitudinal mode structure of the laser resonator. At first, the fast-fourier transform technique is applied for analyzing the mode beating of the optical fields by intensity frequency structure of the laser pulses to determine the number of longitudinal modes. Then, an analyzer etalon is used to observe Fabry-Perot fringes to compute the numbers of the resonator longitudinal modes. The results of two techniques are in good agreement with each other. Under the proper conditions, a reliable single longitudinal mode of the non-planar ring-resonator can be achieved with a good spatial mode profile that originates from the unidirectional travelling optical field propagation in the resonator having a very low sensitivity of the non-planar ring resonator to the optical elements misalignment.

  19. Numerical Investigations of Resonant Layers in a Periodically—Driven Pendulum

    Institute of Scientific and Technical Information of China (English)

    AlbertC.L.LUO

    1999-01-01

    Numerical simulations of the presence of resonant layers formed near a resonant separatrix in a periodically driven pendulum are presented through an energy spectrum method.The analytical predictions are also presented.The resonant layers are illustrated through the Poincare mapping sections.For the strong excitation.The sub-resonance effects should be considered through the self-similarity of resonance in the resonant layers.

  20. Coupling a Transmon Qubit to a Superconducting Metamaterial Resonator

    Science.gov (United States)

    Wang, Haozhi; Hutchings, M.; Indrajeet, Sager; Rouxinol, Francisco; Lahaye, Matthew; Plourde, B. L. T.; Taketani, Bruno G.; Wilhelm, Frank K.

    Arrays of lumped circuit elements can be used to form metamaterial resonant structures that exhibit significantly different mode structures compared to resonators made from conventional distributed transmission lines. In particular, it is possible to produce a high density of modes in the microwave regime where a superconducting qubit can be operated and coupled to the various modes. We will present our low-temperature measurements of such a superconducting metamaterial resonator coupled to a tunable transmon qubit. By tuning the magnetic flux biasing the qubit, we observe vacuum Rabi splittings in the modes that the qubit transition passes through. We will also discuss our measurements of an interaction between neighboring modes of the metamaterial system that is mediated by the qubit. Because of the dispersive coupling of the qubit to the various modes of the system, driving a microwave tone near one mode of the system can have a significant influence on the transmission through another mode, with a strong dependence on the bias point of the qubit. We will compare these measurements with a theoretical model of the system.

  1. Pitchfork bifurcation and vibrational resonance in a fractional-order Duffing oscillator

    Indian Academy of Sciences (India)

    J H Yang; M A F Sanjuán; W Xiang; H Zhu

    2013-12-01

    The pitchfork bifurcation and vibrational resonance are studied in a fractional-order Duffing oscillator with delayed feedback and excited by two harmonic signals. Using an approximation method, the bifurcation behaviours and resonance patterns are predicted. Supercritical and subcritical pitchfork bifurcations can be induced by the fractional-order damping, the exciting highfrequency signal and the delayed time. The fractional-order damping mainly determines the pattern of the vibrational resonance. There is a bifurcation point of the fractional order which, in the case of double-well potential, transforms vibrational resonance pattern from a single resonance to a double resonance, while in the case of single-well potential, transforms vibrational resonance from no resonance to a single resonance. The delayed time influences the location of the vibrational resonance and the bifurcation point of the fractional order. Pitchfork bifurcation is the necessary condition for the double resonance. The theoretical predictions are in good agreement with the numerical simulations.

  2. The diphoton resonance as a gravity mediator of dark matter

    Directory of Open Access Journals (Sweden)

    Chengcheng Han

    2016-04-01

    Full Text Available We consider the possibility of interpreting the recently reported diphoton excess at 750 GeV as a spin-two massive particle (such as a Kaluza–Klein graviton in warped extra-dimensions which serves as a mediator to Dark Matter via its gravitational couplings to the dark sector and to the Standard Model (SM. We model non-universal couplings of the resonance to gauge bosons in the SM and to Dark Matter as a function on their localization in the extra dimension. We find that scalar, fermion or vector dark matter can saturate the dark matter relic density by the annihilation of dark matter into a pair of the SM particles or heavy resonances, in agreement with the diphoton resonance signal strength. We check the compatibility of our hypothesis with other searches for the KK graviton. We show that the invisible decay rate of the resonance into a pair of dark matter is subdominant in the region of the correct relic density, hence leading to no constraints from the mono-jet bound at 8 TeV via the gluon coupling. We also discuss the kinematic features of the decay products of a KK graviton to distinguish the KK graviton from the SM backgrounds or a scalar particle interpretation of the diphoton resonance.

  3. The diphoton resonance as a gravity mediator of dark matter

    Science.gov (United States)

    Han, Chengcheng; Lee, Hyun Min; Park, Myeonghun; Sanz, Verónica

    2016-04-01

    We consider the possibility of interpreting the recently reported diphoton excess at 750 GeV as a spin-two massive particle (such as a Kaluza-Klein graviton in warped extra-dimensions) which serves as a mediator to Dark Matter via its gravitational couplings to the dark sector and to the Standard Model (SM). We model non-universal couplings of the resonance to gauge bosons in the SM and to Dark Matter as a function on their localization in the extra dimension. We find that scalar, fermion or vector dark matter can saturate the dark matter relic density by the annihilation of dark matter into a pair of the SM particles or heavy resonances, in agreement with the diphoton resonance signal strength. We check the compatibility of our hypothesis with other searches for the KK graviton. We show that the invisible decay rate of the resonance into a pair of dark matter is subdominant in the region of the correct relic density, hence leading to no constraints from the mono-jet bound at 8 TeV via the gluon coupling. We also discuss the kinematic features of the decay products of a KK graviton to distinguish the KK graviton from the SM backgrounds or a scalar particle interpretation of the diphoton resonance.

  4. Matrix Formalism for Spin Dynamics Near a Single Depolarization Resonance

    Energy Technology Data Exchange (ETDEWEB)

    Chao, Alexander W.; /SLAC

    2005-10-26

    A matrix formalism is developed to describe the spin dynamics in a synchrotron near a single depolarization resonance as the particle energy (and therefore its spin precession frequency) is varied in a prescribed pattern as a function of time such as during acceleration. This formalism is first applied to the case of crossing the resonance with a constant crossing speed and a finite total step size, and then applied also to other more involved cases when the single resonance is crossed repeatedly in a prescribed manner consisting of linear ramping segments or sudden jumps. How repeated crossings produce an interference behavior is discussed using the results obtained. For a polarized beam with finite energy spread, a spin echo experiment is suggested to explore this interference effect.

  5. Parametric Resonance in the Early Universe - A Fitting Analysis

    CERN Document Server

    Figueroa, Daniel G

    2016-01-01

    Particle production via parametric resonance in the early Universe, is a non-perturbative, non-linear and out-of-equilibrium phenomenon. Although it is a well studied topic, whenever a new scenario exhibits parametric resonance, a full re-analysis is normally required. To avoid this tedious task, many works present often only a simplified linear treatment of the problem. In order to surpass this circumstance in the future, we provide a fitting analysis of parametric resonance through all its relevant stages: initial linear growth, non-linear evolution, and relaxation towards equilibrium. Using lattice simulations in an expanding grid in $3+1$ dimensions, we parametrise the dynamics' outcome scanning over the relevant ingredients: role of the oscillatory field, particle coupling strength, initial conditions, and background expansion rate. We emphasise the inaccuracy of the linear calculation of the decay time of the oscillatory field, and propose a more appropriate definition of this scale based on the subsequ...

  6. Resonance and propulsion performance of a heaving flexible wing

    CERN Document Server

    Michelin, S

    2009-01-01

    The influence of the bending rigidity of a flexible heaving wing on its propulsive performance in a two-dimensional imposed parallel flow is investigated in the inviscid limit. Potential flow theory is used to describe the flow over the flapping wing. The vortical wake of the wing is accounted for by the shedding of point vortices with unsteady intensity from the wing's trailing edge. The trailing-edge flapping amplitude is shown to be maximal for a discrete set of values of the rigidity, at which a resonance occurs between the forcing frequency and a natural frequency of the system. A quantitative comparison of the position of these resonances with linear stability analysis results is presented. Such resonances induce maximum values of the mean developed thrust and power input. The flapping efficiency is also shown to be greatly enhanced by flexibility.

  7. A planar left-handed metamaterial based on electric resonators

    Institute of Scientific and Technical Information of China (English)

    Chen Chun-Hui; Qu Shao-Bo; Wang Jia-Fu; Ma Hua; Wang Xin-Hua; Xu Zhuo

    2011-01-01

    A planar left-handed metamaterial(LHM) composed of electric resonator pairs is presented in this paper. Theoretical analysis, an equivalent circuit model and simulated results of a wedge sample show that this material exhibits a negative refraction pass-band around 9.6GHz under normal-incidence and is insensitive to a change in incidence angle. Furthermore, as the angle between the arm of the electric resonators and the strip connecting the arms increases, the frequency range of the pass-band shifts downwards. Consequently, this LHM guarantees a relatively stable torlerence of errors when it is practically fabricated. Moreover, it is a candidate for designing multi-band LHM through combining the resonator pairs with different angles.

  8. Two-resonator circuit quantum electrodynamics: A superconducting quantum switch

    Science.gov (United States)

    Mariantoni, Matteo; Deppe, Frank; Marx, A.; Gross, R.; Wilhelm, F. K.; Solano, E.

    2008-09-01

    We introduce a systematic formalism for two-resonator circuit QED, where two on-chip microwave resonators are simultaneously coupled to one superconducting qubit. Within this framework, we demonstrate that the qubit can function as a quantum switch between the two resonators, which are assumed to be originally independent. In this three-circuit network, the qubit mediates a geometric second-order circuit interaction between the otherwise decoupled resonators. In the dispersive regime, it also gives rise to a dynamic second-order perturbative interaction. The geometric and dynamic coupling strengths can be tuned to be equal, thus permitting to switch on and off the interaction between the two resonators via a qubit population inversion or a shifting of the qubit operation point. We also show that our quantum switch represents a flexible architecture for the manipulation and generation of nonclassical microwave field states as well as the creation of controlled multipartite entanglement in circuit QED. In addition, we clarify the role played by the geometric interaction, which constitutes a fundamental property characteristic of superconducting quantum circuits without a counterpart in quantum-optical systems. We develop a detailed theory of the geometric second-order coupling by means of circuit transformations for superconducting charge and flux qubits. Furthermore, we show the robustness of the quantum switch operation with respect to decoherence mechanisms. Finally, we propose a realistic design for a two-resonator circuit QED setup based on a flux qubit and estimate all the related parameters. In this manner, we show that this setup can be used to implement a superconducting quantum switch with available technology.

  9. Strong coupling of paramagnetic spins to a superconducting microwave resonator

    Energy Technology Data Exchange (ETDEWEB)

    Greifenstein, Moritz; Zollitsch, Christoph; Lotze, Johannes; Hocke, Fredrik; Goennenwein, Sebastian T.B.; Huebl, Hans [Walther-Meissner-Institut (WMI), Garching (Germany); Gross, Rudolf [Walther-Meissner-Institut (WMI), Garching (Germany); Physik-Department, TU Muenchen, Garching (Germany)

    2012-07-01

    Under application of an external magnetic field, non-interacting electron spins behave as an ensemble of identical two-level-systems with tuneable transition frequency. When such an ensemble collectively interacts with a single mode of an electromagnetic resonator, the entire system can be described as two coupled quantum harmonic oscillators. The criterion for the observation of the so-called strong coupling regime is that the collective coupling strength g exceeds both the loss rate of the resonator {kappa} and of the spin ensemble {gamma}. In our experiment we realize a coupled spin-photon-system by introducing the spin marker DPPH (2,2-diphenyl-1-picrylhydrazyl) into the mode volume of a superconducting coplanar microwave resonator and investigate the interaction at 2.5, 5.0 and 7.5 GHz. For tuning the resonance, we apply an in-plane magnetic field and observe interaction at around {+-}90, {+-}180 and {+-}270 mT. While the coupling with the fundamental mode and the first harmonic mode of the resonator is identified as weak, the second harmonic shows g=21 MHz, {kappa} = 6 MHz and {gamma} = 5 MHz, i.e. the strong coupling regime. We further investigate the dependence of g on temperature and on microwave input power.

  10. Ferromagnetic resonance and resonance modes in kagome lattices: From an open to a closed kagome structure

    Science.gov (United States)

    Dubowik, J.; Kuświk, P.; Matczak, M.; Bednarski, W.; Stobiecki, F.; Aleshkevych, P.; Szymczak, H.; Kisielewski, M.; Kisielewski, J.

    2016-06-01

    We present ferromagnetic resonance (FMR) investigations of 20 nm thick permalloy (Ni80Fe20 ) elements (width W =200 nm, length L =470 nm, period a =500 nm) arranged in open and closed artificial kagome lattices. The measurements were done at 9.4 and 34 GHz to ensure a saturated or near-saturated magnetic state of the kagome structures. The FMR data are analyzed in the framework of an analytical macrospin model which grasps the essential features of the bulk and edge modes at these microwave frequencies and is in agreement with the results of micromagnetic simulations. Polar plots of the resonance fields versus the field angle made by the direction of the magnetic field with respect to the main symmetry directions of the kagome lattice are compared with the results of the analytical model. The measured FMR spectra with a sixfold rotational symmetry qualitatively reproduce the structure expected from the theory. Magnetic dipolar interactions between the elements of the kagome lattices result in the mixing of edge and bulklike excitations at 9.4 GHz and in a systematic deviation from the model, especially for the closed kagome lattice.

  11. Resonances of the helium atom in a strong magnetic field

    DEFF Research Database (Denmark)

    Lühr, Armin Christian; Al-Hujaj, Omar-Alexander; Schmelcher, Peter

    2007-01-01

    We present an investigation of the resonances of a doubly excited helium atom in a strong magnetic field covering the regime B=0–100  a.u. A full-interaction approach which is based on an anisotropic Gaussian basis set of one-particle functions being nonlinearly optimized for each field strength...... is employed. Accurate results for a total of 17 resonances below the threshold consisting of He+ in the N=2 state are reported in this work. This includes states with total magnetic quantum numbers M=0,−1,−2 and even z parity. The corresponding binding energies are compared to approximate energies of two......-particle configurations consisting of two hydrogenlike electrons in the strong-field regime, thereby providing an understanding of the behavior of the energies of the resonances with varying field strength....

  12. Design and Analyses of a MEMS Based Resonant Magnetometer.

    Science.gov (United States)

    Ren, Dahai; Wu, Lingqi; Yan, Meizhi; Cui, Mingyang; You, Zheng; Hu, Muzhi

    2009-01-01

    A novel design of a MEMS torsional resonant magnetometer based on Lorentz force is presented and fabricated. The magnetometer consists of a silicon resonator, torsional beam, excitation coil, capacitance plates and glass substrate. Working in a resonant condition, the sensor's vibration amplitude is converted into the sensing capacitance change, which reflects the outside magnetic flux-density. Based on the simulation, the key structure parameters are optimized and the air damping effect is estimated. The test results of the prototype are in accordance with the simulation results of the designed model. The resolution of the magnetometer can reach 30 nT. The test results indicate its sensitivity of more than 400 mV/μT when operating in a 10 Pa vacuum environment. PMID:22399981

  13. Design and Analyses of a MEMS Based Resonant Magnetometer

    Directory of Open Access Journals (Sweden)

    Dahai Ren

    2009-09-01

    Full Text Available A novel design of a MEMS torsional resonant magnetometer based on Lorentz force is presented and fabricated. The magnetometer consists of a silicon resonator, torsional beam, excitation coil, capacitance plates and glass substrate. Working in a resonant condition, the sensor’s vibration amplitude is converted into the sensing capacitance change, which reflects the outside magnetic flux-density. Based on the simulation, the key structure parameters are optimized and the air damping effect is estimated. The test results of the prototype are in accordance with the simulation results of the designed model. The resolution of the magnetometer can reach 30 nT. The test results indicate its sensitivity of more than 400 mV/μT when operating in a 10 Pa vacuum environment.

  14. Cluster structure of a low-energy resonance in tetraneutron

    CERN Document Server

    Lashko, Y; Filippov, Gennady; Lashko, Yuliya

    2006-01-01

    We theoretically investigate the possibility for a tetraneutron to exist as a low-energy resonance state. We explore a microscopic model based on the assumption that the tetraneutron can be treated as a compound system where $^3$n+n and $^2$n+$^2$n coupled cluster configurations coexist. The influence of the Pauli principle on the kinetic energy of the relative motion of the neutron clusters is shown to result in their attraction. The strength of such attraction is high enough to ensure the existence of a low-energy resonance in the tetraneutron, provided that the oscillator length is large enough.

  15. Design and Implementation of a Micromechanical Silicon Resonant Accelerometer

    Directory of Open Access Journals (Sweden)

    Libin Huang

    2013-11-01

    Full Text Available The micromechanical silicon resonant accelerometer has attracted considerable attention in the research and development of high-precision MEMS accelerometers because of its output of quasi-digital signals, high sensitivity, high resolution, wide dynamic range, anti-interference capacity and good stability. Because of the mismatching thermal expansion coefficients of silicon and glass, the micromechanical silicon resonant accelerometer based on the Silicon on Glass (SOG technique is deeply affected by the temperature during the fabrication, packaging and use processes. The thermal stress caused by temperature changes directly affects the frequency output of the accelerometer. Based on the working principle of the micromechanical resonant accelerometer, a special accelerometer structure that reduces the temperature influence on the accelerometer is designed. The accelerometer can greatly reduce the thermal stress caused by high temperatures in the process of fabrication and packaging. Currently, the closed-loop drive circuit is devised based on a phase-locked loop. The unloaded resonant frequencies of the prototype of the micromechanical silicon resonant accelerometer are approximately 31.4 kHz and 31.5 kHz. The scale factor is 66.24003 Hz/g. The scale factor stability is 14.886 ppm, the scale factor repeatability is 23 ppm, the bias stability is 23 μg, the bias repeatability is 170 μg, and the bias temperature coefficient is 0.0734 Hz/°C.

  16. Head-Positioning Control Using Virtual Resonant Modes in a Hard Disk Drive

    Science.gov (United States)

    Atsumi, Takenori

    In conventional control systems in hard disk drives, it is difficult to compensate for disturbances above the primary mechanical resonance. In this paper, a design method that uses a virtual resonant mode in head-positioning systems of hard disk drives was developed. The virtual resonant mode is a digital filter that works like a mechanical resonant mode. Using the proposed method, stable resonant modes in a control system can be designed with a high degree of accuracy to compensate for disturbances whose frequencies are higher than that of the primary mechanical resonance. Application of this method to a hard disk drive showed that it significantly suppresses disturbances beyond the primary mechanical resonance.

  17. Analysis of a Precambrian resonance-stabilized day length

    CERN Document Server

    Bartlett, Benjamin C

    2015-01-01

    Stromatolite data suggest the day length throughout much of the Precambrian to be relatively constant near 21 hours; this period would have been resonant with the semidiurnal atmospheric tide. At this point, the atmospheric torque would have been nearly maximized, being comparable in magnitude but opposite in direction to the lunar torque, halting Earth's angular deceleration, as suggested by Zahnle and Walker [1987]. Computational simulations of this scenario indicate that, depending on the atmospheric $Q$-factor, a persistent increase in temperature larger than ~10K over a period of time less than $10^7$ years will break resonance, such as the deglaciation following a snowball event near the end of the Precambrian. The resonance was found to be relatively unaffected by other forms of climate fluctuation (thermal noise). Our model provides a simulated day length over time that matches existing records of day length, though further data is needed.

  18. Observation of decoherence in a carbon nanotube mechanical resonator

    Science.gov (United States)

    Schneider, Ben H.; Singh, Vibhor; Venstra, Warner J.; Meerwaldt, Harold B.; Steele, Gary A.

    2014-12-01

    In physical systems, decoherence can arise from both dissipative and dephasing processes. In mechanical resonators, the driven frequency response measures a combination of both, whereas time-domain techniques such as ringdown measurements can separate the two. Here we report the first observation of the mechanical ringdown of a carbon nanotube mechanical resonator. Comparing the mechanical quality factor obtained from frequency- and time-domain measurements, we find a spectral quality factor four times smaller than that measured in ringdown, demonstrating dephasing-induced decoherence of the nanomechanical motion. This decoherence is seen to arise at high driving amplitudes, pointing to a nonlinear dephasing mechanism. Our results highlight the importance of time-domain techniques for understanding dissipation in nanomechanical resonators, and the relevance of decoherence mechanisms in nanotube mechanics.

  19. Resonance spectrum of a bulk fermion on branes

    Science.gov (United States)

    Zhang, Yu-Peng; Du, Yun-Zhi; Guo, Wen-Di; Liu, Yu-Xiao

    2016-03-01

    It is known that there are two mechanisms for localizing a bulk fermion on a brane: one is the well-known Yukawa coupling, and the other is the new coupling proposed in [Phys. Rev. D 89, 086001 (2014)]. In this paper, we investigate the localization and resonance spectrum of a bulk fermion on the same branes with the two localization mechanisms. It is found that both of the two mechanisms can result in a volcano-like effective potential of the fermion Kaluza-Klein modes. The left-chiral fermion zero mode can be localized on the brane, and there exist some discrete massive-fermion Kaluza-Klein modes that quasilocalized on the branes (also called fermion resonances). The number of the fermion resonances increases linearly with the coupling parameter.

  20. Observation of decoherence in a carbon nanotube mechanical resonator.

    Science.gov (United States)

    Schneider, Ben H; Singh, Vibhor; Venstra, Warner J; Meerwaldt, Harold B; Steele, Gary A

    2014-12-19

    In physical systems, decoherence can arise from both dissipative and dephasing processes. In mechanical resonators, the driven frequency response measures a combination of both, whereas time-domain techniques such as ringdown measurements can separate the two. Here we report the first observation of the mechanical ringdown of a carbon nanotube mechanical resonator. Comparing the mechanical quality factor obtained from frequency- and time-domain measurements, we find a spectral quality factor four times smaller than that measured in ringdown, demonstrating dephasing-induced decoherence of the nanomechanical motion. This decoherence is seen to arise at high driving amplitudes, pointing to a nonlinear dephasing mechanism. Our results highlight the importance of time-domain techniques for understanding dissipation in nanomechanical resonators, and the relevance of decoherence mechanisms in nanotube mechanics.

  1. A Microring Resonator Based Negative Permeability Metamaterial Sensor

    Directory of Open Access Journals (Sweden)

    Yao-Zhong Lan

    2011-08-01

    Full Text Available Metamaterials are artificial multifunctional materials that acquire their material properties from their structure, rather than inheriting them directly from the materials they are composed of, and they may provide novel tools to significantly enhance the sensitivity and resolution of sensors. In this paper, we derive the dispersion relation of a cylindrical dielectric waveguide loaded on a negative permeability metamaterial (NPM layer, and compute the resonant frequencies and electric field distribution of the corresponding Whispering-Gallery-Modes (WGMs. The theoretical resonant frequency and electric field distribution results are in good agreement with the full wave simulation results. We show that the NPM sensor based on a microring resonator possesses higher sensitivity than the traditional microring sensor since with the evanescent wave amplification and the increase of NPM layer thickness, the sensitivity will be greatly increased. This may open a door for designing sensors with specified sensitivity.

  2. Resonance spectrum of a bulk fermion on branes

    CERN Document Server

    Zhang, Yu-Peng; Guo, Wen-Di; Liu, Yu-Xiao

    2016-01-01

    It is known that there are two mechanisms for localizing a bulk fermion on a brane, one is the well-known Yukawa coupling and the other is the new coupling proposed in [Phys. Rev. D 89, 086001 (2014)]. In this paper, we investigate localization and resonance spectrum of a bulk fermion on the same branes with the two localization mechanisms. It is found that both the two mechanisms can result in a volcano-like effective potential of the fermion Kaluza-Klein modes. The left-chiral fermion zero mode can be localized on the brane and there exist some discrete massive fermion Kaluza-Klein modes that quasilocalized on the brane (also called fermion resonances). The number of the fermion resonances increases linearly with the coupling parameter.

  3. Dynamic nuclear polarization in a magnetic resonance force microscope experiment.

    Science.gov (United States)

    Issac, Corinne E; Gleave, Christine M; Nasr, Paméla T; Nguyen, Hoang L; Curley, Elizabeth A; Yoder, Jonilyn L; Moore, Eric W; Chen, Lei; Marohn, John A

    2016-04-01

    We report achieving enhanced nuclear magnetization in a magnetic resonance force microscope experiment at 0.6 tesla and 4.2 kelvin using the dynamic nuclear polarization (DNP) effect. In our experiments a microwire coplanar waveguide delivered radiowaves to excite nuclear spins and microwaves to excite electron spins in a 250 nm thick nitroxide-doped polystyrene sample. Both electron and proton spin resonance were observed as a change in the mechanical resonance frequency of a nearby cantilever having a micron-scale nickel tip. NMR signal, not observable from Curie-law magnetization at 0.6 T, became observable when microwave irradiation was applied to saturate the electron spins. The resulting NMR signal's size, buildup time, dependence on microwave power, and dependence on irradiation frequency was consistent with a transfer of magnetization from electron spins to nuclear spins. Due to the presence of an inhomogeneous magnetic field introduced by the cantilever's magnetic tip, the electron spins in the sample were saturated in a microwave-resonant slice 10's of nm thick. The spatial distribution of the nuclear polarization enhancement factor ε was mapped by varying the frequency of the applied radiowaves. The observed enhancement factor was zero for spins in the center of the resonant slice, was ε = +10 to +20 for spins proximal to the magnet, and was ε = -10 to -20 for spins distal to the magnet. We show that this bipolar nuclear magnetization profile is consistent with cross-effect DNP in a ∼10(5) T m(-1) magnetic field gradient. Potential challenges associated with generating and using DNP-enhanced nuclear magnetization in a nanometer-resolution magnetic resonance imaging experiment are elucidated and discussed. PMID:26964007

  4. Dynamic nuclear polarization in a magnetic resonance force microscope experiment.

    Science.gov (United States)

    Issac, Corinne E; Gleave, Christine M; Nasr, Paméla T; Nguyen, Hoang L; Curley, Elizabeth A; Yoder, Jonilyn L; Moore, Eric W; Chen, Lei; Marohn, John A

    2016-04-01

    We report achieving enhanced nuclear magnetization in a magnetic resonance force microscope experiment at 0.6 tesla and 4.2 kelvin using the dynamic nuclear polarization (DNP) effect. In our experiments a microwire coplanar waveguide delivered radiowaves to excite nuclear spins and microwaves to excite electron spins in a 250 nm thick nitroxide-doped polystyrene sample. Both electron and proton spin resonance were observed as a change in the mechanical resonance frequency of a nearby cantilever having a micron-scale nickel tip. NMR signal, not observable from Curie-law magnetization at 0.6 T, became observable when microwave irradiation was applied to saturate the electron spins. The resulting NMR signal's size, buildup time, dependence on microwave power, and dependence on irradiation frequency was consistent with a transfer of magnetization from electron spins to nuclear spins. Due to the presence of an inhomogeneous magnetic field introduced by the cantilever's magnetic tip, the electron spins in the sample were saturated in a microwave-resonant slice 10's of nm thick. The spatial distribution of the nuclear polarization enhancement factor ε was mapped by varying the frequency of the applied radiowaves. The observed enhancement factor was zero for spins in the center of the resonant slice, was ε = +10 to +20 for spins proximal to the magnet, and was ε = -10 to -20 for spins distal to the magnet. We show that this bipolar nuclear magnetization profile is consistent with cross-effect DNP in a ∼10(5) T m(-1) magnetic field gradient. Potential challenges associated with generating and using DNP-enhanced nuclear magnetization in a nanometer-resolution magnetic resonance imaging experiment are elucidated and discussed.

  5. Analysis and experimental realization of locally resonant phononic plates carrying a periodic array of beam-like resonators

    International Nuclear Information System (INIS)

    We present theoretical examination and experimental demonstration of locally resonant (LR) phononic plates consisting of a periodic array of beam-like resonators attached to a thin homogeneous plate. Such phononic plates feature unique wave physics due to the coexistence of localized resonance and structural periodicity. We demonstrate that a low-frequency complete band gap for flexural plate waves can be created in the proposed structure owing to the interaction between the localized resonant modes of the beam-like resonators and the flexural wave modes of the host plate. We show that the location and width of the complete band gap can be dramatically tuned by changing the properties of the beam-like resonators. To understand the opening mechanism and evolution behaviour of the complete band gap, some approximate but explicit models are provided and discussed. We further perform experimental measurements of a specimen fabricated by an array of double-stacked aluminum beam-like resonators attached to a thin aluminum plate with 5 cm structure periodicity. The experimental results evidence a complete band gap extending from 465 to 860 Hz, matching well with our theoretical prediction. The LR phononic plates proposed in this work can find potential applications in attenuation of low-frequency mechanical vibrations and insulation of low-frequency audible sound. (paper)

  6. Josephson Plasma Resonance as a Structural Probe of Vortex Liquid

    International Nuclear Information System (INIS)

    Recent developments of the Josephson plasma resonance and transport c -axis measurements in layered high Tc superconductors allow one to probe Josephson coupling in a wide range of the vortex phase diagram. We derive a relation between the field dependent Josephson coupling energy and the density correlation function of the vortex liquid. This relation provides a unique opportunity to extract the density correlation function of pancake vortices from the dependence of the plasma resonance on the ab component of the magnetic field at a fixed c -axis component. copyright 1998 The American Physical Society

  7. Modeling of a Resonant Tunneling Diode Optical Modulator

    CERN Document Server

    Calado, J J N; Ironside, C N

    2005-01-01

    The integration of a double barrier resonant tunneling diode within a unipolar optical waveguide provides electrical gain over a wide bandwidth. Due to the non-linearities introduced by the double barrier resonant tunneling diode an unipolar InGaAlAs/InP optical waveguide can be employed both as optical modulator and optical detector. The modeling results of a device operating as optical modulator agree with preliminary experimental data, foreseeing for an optimized device modulation depths up to 23 dB with chirp parameter between -1 and 0 in the wavelength range analyzed (1520 nm - 1600 nm).

  8. Anthropogenic sources stimulate resonance of a natural rock bridge

    Science.gov (United States)

    Moore, Jeffrey R.; Thorne, Michael S.; Koper, Keith D.; Wood, John R.; Goddard, Kyler; Burlacu, Relu; Doyle, Sarah; Stanfield, Erik; White, Benjamin

    2016-09-01

    The natural modes of vibration of bedrock landforms, as well as the sources and effects of stimulated resonance remain poorly understood. Here we show that seismic energy created by an induced earthquake and an artificial reservoir has spectral content coincident with the natural modes of vibration of a prominent rock bridge. We measured the resonant frequencies of Rainbow Bridge, Utah using data from two broadband seismometers placed on the span, and identified eight distinct vibrational modes between 1 and 6 Hz. A distant, induced earthquake produced local ground motion rich in 1 Hz energy, stimulating a 20 dB increase in measured power at the bridge's fundamental mode. Moreover, we establish that wave action on Lake Powell, an artificial reservoir, generates microseismic energy with peak power ~1 Hz, also exciting resonance of Rainbow Bridge. These anthropogenic sources represent relatively new energy input for the bridge with unknown consequences for structural fatigue.

  9. Dynamical resonances and SSF singularities for a magnetic Schroedinger operator

    CERN Document Server

    Astaburuaga, Maria Angélica; Bruneau, Vincent; Fernandez, Claudio; Raikov, Georgi

    2007-01-01

    We consider the Hamiltonian $H$ of a 3D spinless non-relativistic quantum particle subject to parallel constant magnetic and non-constant electric field. The operator $H$ has infinitely many eigenvalues of infinite multiplicity embedded in its continuous spectrum. We perturb $H$ by appropriate scalar potentials $V$ and investigate the transformation of these embedded eigenvalues into resonances. First, we assume that the electric potentials are dilation-analytic with respect to the variable along the magnetic field, and obtain an asymptotic expansion of the resonances as the coupling constant $\\varkappa$ of the perturbation tends to zero. Further, under the assumption that the Fermi Golden Rule holds true, we deduce estimates for the time evolution of the resonance states with and without analyticity assumptions; in the second case we obtain these results as a corollary of suitable Mourre estimates and a recent article of Cattaneo, Graf and Hunziker \\cite{cgh}. Next, we describe sets of perturbations $V$ for ...

  10. A second generation of low thermal noise cryogenic silicon resonators

    Science.gov (United States)

    Matei, D. G.; Legero, T.; Grebing, Ch; Häfner, S.; Lisdat, Ch; Weyrich, R.; Zhang, W.; Sonderhouse, L.; Robinson, J. M.; Riehle, F.; Ye, J.; Sterr, U.

    2016-06-01

    We have set up an improved vertically mounted silicon cavity operating at the zero-crossing temperature of the coefficient of thermal expansion (CTE) near 123 K with estimated thermal noise limited instability of 4 x 10-17 in the modified Allan deviation. Owing to the anisotropic elasticity of single-crystal silicon, the vertical acceleration sensitivity was minimized in situ by axially rotating the resonator with respect to the mounting frame. The control of the resonator temperature is greatly improved by using a combination of two thermal shields, monitoring with several temperature sensors, and employing low-thermal conductivity materials. The instability of the resonator stabilized laser was characterized by comparing with another low-noise system based on a 48 cm long room temperature cavity of PTB's strontium lattice clock, resulting in a modified Allan deviation of 7 x 10-17 at 100 s.

  11. Analytic Solution of the Electromagnetic Eigenvalues Problem in a Cylindrical Resonator

    CERN Document Server

    Checchin, Mattia

    2016-01-01

    Resonant accelerating cavities are key components in modern particles accelerating facilities. These take advantage of electromagnetic fields resonating at microwave frequencies to accelerate charged particles. Particles gain finite energy at each passage through a cavity if in phase with the resonating field, reaching energies even of the order of $TeV$ when a cascade of accelerating resonators are present. In order to understand how a resonant accelerating cavity transfers energy to charged particles, it is important to determine how the electromagnetic modes are exited into such resonators. In this paper we present a complete analytical calculation of the resonating fields for a simple cylindrical-shaped cavity.

  12. Manipulating the conduction process of a molecular resonant tunneling diode

    International Nuclear Information System (INIS)

    In this work we propose two methods to manipulate the conduction process in a molecular resonant tunneling diode. In the first proposal we make use of the fact that by twisting the molecule along the long axis, we can generate a nonlinear coupling between the conduction electrons and the phonons. In the second proposal, we allow a light of appropriate frequency to pump the electrons from the ground state to the first excited state. This mechanism generates an additional current across the molecular resonant tunneling diode. (author)

  13. A Prototype-Based Resonance Model of Rhythm Categorization

    Directory of Open Access Journals (Sweden)

    Rasmus Bååth

    2014-10-01

    Full Text Available Categorization of rhythmic patterns is prevalent in musical practice, an example of this being the transcription of (possibly not strictly metrical music into musical notation. In this article we implement a dynamical systems' model of rhythm categorization based on the resonance theory of rhythm perception developed by Large (2010. This model is used to simulate the categorical choices of participants in two experiments of Desain and Honing (2003. The model accurately replicates the experimental data. Our results support resonance theory as a viable model of rhythm perception and show that by viewing rhythm perception as a dynamical system it is possible to model central properties of rhythm categorization.

  14. Magnetic resonance imaging as a tool for extravehicular activity analysis

    Science.gov (United States)

    Dickenson, R.; Lorenz, C.; Peterson, S.; Strauss, A.; Main, J.

    1992-01-01

    The purpose of this research is to examine the value of magnetic resonance imaging (MRI) as a means of conducting kinematic studies of the hand for the purpose of EVA capability enhancement. After imaging the subject hand using a magnetic resonance scanner, the resulting 2D slices were reconstructed into a 3D model of the proximal phalanx of the left hand. Using the coordinates of several landmark positions, one is then able to decompose the motion of the rigid body. MRI offers highly accurate measurements due to its tomographic nature without the problems associated with other imaging modalities for in vivo studies.

  15. Matter Neutrino Resonance Transitions above a Neutron Star Merger Remnant

    CERN Document Server

    Zhu, Yong-Lin; McLaughlin, Gail C

    2016-01-01

    The Matter-Neutrino Resonance (MNR) phenomenon has the potential to significantly alter the flavor content of neutrinos emitted from compact object mergers. We present the first calculations of MNR transitions using neutrino self interaction potentials and matter potentials generated selfconsistently from a dynamical model of a three-dimensional neutron star merger. In the context of the single angle approximation, we find that Symmetric and Standard MNR transitions occur in both normal and inverted hierarchy scenarios. We examine the spatial regions above the merger remnant where propagating neutrinos will encounter the matter neutrino resonance and find that a significant fraction of the neutrinos are likely to undergo MNR transitions.

  16. A graphene based tunable terahertz sensor with double Fano resonances

    Science.gov (United States)

    Zhang, Yuping; Li, Tongtong; Zeng, Beibei; Zhang, Huiyun; Lv, Huanhuan; Huang, Xiaoyan; Zhang, Weili; Azad, Abul K.

    2015-07-01

    We propose an ultrasensitive terahertz (THz) sensor consisting of a subwavelength graphene disk and an annular gold ring within a unit cell. The interference between the resonances arising from the graphene disk and the gold ring gives rise to Fano type resonances and enables ultrasensitive sensing. Our full wave electromagnetic simulations show frequency sensitivity as high as 1.9082 THz per refractive index unit (RIU) and a figure of merit (FOM) of 6.5662. Furthermore, the sensing range can be actively tuned by adjusting the Fermi level of graphene.

  17. A 10-GHz film-thickness-mode cavity optomechanical resonator

    Science.gov (United States)

    Han, Xu; Fong, King Y.; Tang, Hong X.

    2015-04-01

    We report on the advance of chip-scale cavity optomechanical resonators to beyond 10 GHz by exploiting the fundamental acoustic thickness mode of an aluminum nitride micro-disk. By engineering the mechanical anchor to minimize the acoustic loss, a quality factor of 1830 and hence a frequency-quality factor product of 1.9 × 1013 Hz are achieved in ambient air at room temperature. Actuated by strong piezo-electric force, the micro-disk resonator shows an excellent electro-optomechanical transduction efficiency. Our detailed analysis of the electro-optomechanical coupling allows identification and full quantification of various acoustic modes spanning from super-high to X-band microwave frequencies measured in the thin film resonator.

  18. Control of a resonant tunneling structure by intense laser fields

    Science.gov (United States)

    Aktas, S.; Kes, H.; Boz, F. K.; Okan, S. E.

    2016-10-01

    The intense laser field effects on a resonant tunneling structure were studied using computational methods. The considered structure was a GaAs/InxGa1-xAs/Al0.3Ga0.7As/InyGa1-yAs/AlAs/GaAs well-barrier system. In the presence of intense laser fields, the transmission coefficient and the dwell time of the structure were calculated depending on the depth and the width of InGaAs wells. It was shown that an intense laser field provides full control on the performance of the device as the geometrical restrictions on the resonant tunneling conditions overcome. Also, the choice of the resonant energy value becomes possible depending on the field strength.

  19. Resonance-like tunneling across a barrier with adjacent wells

    Indian Academy of Sciences (India)

    S Mahadevan; P Prema; S K Agarwalla; B Sahu; C S Shastry

    2006-09-01

    We examine the behavior of transmission coefficient across the rectangular barrier when attractive potential well is present on one or both sides and also the same is studied for a smoother barrier with smooth adjacent wells having Woods–Saxon shape. We find that presence of well with suitable width and depth can substantially alter at energies below the barrier height leading to resonant-like structures. In a sense, this work is complementary to the resonant tunneling of particles across two rectangular barriers, which is being studied in detail in recent years with possible applications in mind. We interpret our results as due to resonant-like positive energy states generated by the adjacent wells. We describe in detail the possible potential application of these results in electronic devices using n-type oxygen-doped gallium arsenide and silicon dioxide. It is envisaged that these results will have applications in the design of tunneling devices.

  20. Initial state dependence of a quantum-resonance ratchet

    CERN Document Server

    Ni, Jiating; Dadras, Siamak; Borunda, Mario F; Wimberger, Sandro; Summy, Gil S

    2016-01-01

    We demonstrate quantum resonance ratchets created with Bose-Einstein condensates exposed to pulses of an off-resonant standing light wave. We show how some of the basic properties of the ratchets are controllable through the creation of different initial states of the system. In particular, our results prove that through an appropriate choice of initial state it is possible to reduce the extent to which the ratchet state changes with respect to time. We develop a simple theory to explain our results and indicate how ratchets might be used as part of a matter wave interferometer or quantum-random walk experiment.

  1. Stochastic Resonance in Linear Regime of a Single- Mode Laser

    Institute of Scientific and Technical Information of China (English)

    ZHANG Liang-Ying; CAO Li; WU Da-Jin; WANG Jun

    2003-01-01

    We present an analytic investigation of the signal-to-noise ratio by studying the linear model of a single-mode laser driven by coloured pump noise (TI) and coloured quantum noise (TZ) with coloured cross-correlation (TS), and obtain an exact analytic expression of the signal-to-noise ratio. We detect that the stochastic resonance occurs when the noise correlation coefficient A < 0. Furthermore, we analyse the effect of TI , T2 and Ta on the signal-to-noise ratio, and derive the condition under which the stochastic resonance occurs.

  2. Properties of Nucleon Resonances by means of a Genetic Algorithm

    CERN Document Server

    Fernandez-Ramirez, C; Udias, A; Udias, J M

    2008-01-01

    We present an optimization scheme that employs a Genetic Algorithm (GA) to determine the properties of low-lying nucleon excitations within a realistic photo-pion production model based upon an effective Lagrangian. We show that with this modern optimization technique it is possible to reliably assess the parameters of the resonances and the associated error bars as well as to identify weaknesses in the models. To illustrate the problems the optimization process may encounter, we provide results obtained for the nucleon resonances $\\Delta$(1230) and $\\Delta$(1700). The former can be easily isolated and thus has been studied in depth, while the latter is not as well known experimentally.

  3. Nucleon-antinucleon resonance spectrum in a potential model

    Science.gov (United States)

    Lacombe, M.; Loiseau, B.; Moussallam, B.; Mau, R. Vinh

    1984-05-01

    We investigate the spectrum of antinucleon-nucleon resonances, using an optical potential we derived recently. An effective method to compute the S-matrix poles is presented. The corresponding phase shifts do not behave as ordinary resonances in the Argand diagram. We show, however, that the poles can be located by extrapolating the phase shifts with the aid of polynomial fits. The annihilation part of our potential is state and energy dependent and of short range. It yields a richer spectrum than that given by a longer ranged annihilation model.

  4. A Spectral-Scanning Magnetic Resonance Imaging (MRI) Integrated System

    OpenAIRE

    Hassibi, Arjang; Babakhani, Aydin; Hajimiri, Ali

    2008-01-01

    An integrated spectral-scanning magnetic resonance imaging (MRI) technique is implemented in a 0.12μm SiGe BiCMOS process. This system is designed for small-scale MRI applications with non-uniform and low magnetic fields. The system is capable of generating customized magnetic resonance (MR) excitation signals, and also recovering the MR response using a coherent direct conversion receiver. The operation frequency is tunable from DC to 37MHz for wide-band MRI and up to...

  5. Fast Resonance Raman Spectroscopy of a Free Radical

    DEFF Research Database (Denmark)

    Wilbrandt, Robert Walter; Pagsberg, Palle Bjørn; Hansen, K. B.;

    1975-01-01

    The resonance Raman spectrum of a 10−3 molar solution of the stable diphenyl-pikryl-hydrazyl radical in benzene was obtained using a single laser pulse of 10 mJ energy and 600 ns duration from a flashlamp pumped tunable dye laser. Spectra were recorded using an image intensifier coupled to a TV...

  6. Dynamics of a Josephson Array in a Resonant Cavity

    OpenAIRE

    Almaas, E.; Stroud, D.

    2001-01-01

    We derive dynamical equations for a Josephson array coupled to a resonant cavity by applying the Heisenberg equations of motion to a model Hamiltonian described by us earlier [Phys. Rev. B {\\bf 63}, 144522 (2001); Phys. Rev. B {\\bf 64}, 179902 (E)]. By means of a canonical transformation, we also show that, in the absence of an applied current and dissipation, our model reduces to one described by Shnirman {\\it et al} [Phys. Rev. Lett. {\\bf 79}, 2371 (1997)] for coupled qubits, and that it co...

  7. Study of nuclear giant resonances using a Fermi-liquid method

    CERN Document Server

    Sun, Bao-Xi

    2012-01-01

    The nuclear giant resonances are studied by using a Fermi-liquid method, and the nuclear collective excitation energies of different values of $l$ are obtained, which are fitted with the centroid energies of the giant resonances of spherical nuclei, respectively. In addition, the relation between the isovector giant resonance and the corresponding isoscalar giant resonance is discussed.

  8. Harvesting energy from airflow with a michromachined piezoelectric harvester inside a Helmholtz resonator

    NARCIS (Netherlands)

    Matova, S.P.; Elfrink, R.; Vullers, R.J.M.; Schaijk, R. van

    2011-01-01

    In this paper we report an airflow energy harvester that combines a piezoelectric energy harvester with a Helmholtz resonator. The resonator converts airflow energy to air oscillations which in turn are converted into electrical energy by a piezoelectric harvester. Two Helmholtz resonators with adju

  9. Entanglement and decoherence of a micromechanical resonator via coupling to a Cooper box

    OpenAIRE

    Armour, A. D.; Blencowe, M. P.; Schwab, K. C.

    2001-01-01

    We analyse the quantum dynamics of a micromechanical resonator capacitively coupled to a Cooper box. With appropriate quantum state control of the Cooper box, the resonator can be driven into a superposition of spatially separated states. The Cooper box can also be used to probe the environmentally-induced decoherence of the resonator superposition state.

  10. Dual-Resonator Speed Meter for a Free Test Mass

    CERN Document Server

    Braginsky, V B; Khalili, F Ya; Thorne, K S; Braginsky, Vladimir B.; Gorodetsky, Mikhail L.; Khalili, Farid Ya.; Thorne, Kip S.

    2000-01-01

    A description and analysis are given of a ``speed meter'' for monitoring a classical force that acts on a test mass. This speed meter is based on two microwave resonators (``dual resonators''), one of which couples evanescently to the position of the test mass. The sloshing of the resulting signal between the resonators, and a wise choice of where to place the resonators' output waveguide, produce a signal in the waveguide that (for sufficiently low frequencies) is proportional to the test-mass velocity (speed) rather than its position. This permits the speed meter to achieve force-measurement sensitivities better than the standard quantum limit (SQL), both when operating in a narrow-band mode and a wide-band mode. A scrutiny of experimental issues shows that it is feasible, with current technology, to construct a demonstration speed meter that beats the wide-band SQL by a factor 2. A concept is sketched for an adaptation of this speed meter to optical frequencies; this adaptation forms the basis for a possib...

  11. Recommended formulae and formats for a resonance parameter library

    International Nuclear Information System (INIS)

    It is proposed that a library of neutron resonance parameters be set up, on punched cards and magnetic tape, which will complement the cross section data in the present U.K. Nuclear Data Library. This report gives parametric formulae for the resolved resonance region, based on:- (i) the Breit-Wigner approximation, (ii) other approximations of R-matrix theory and (iii) the formulae of Adler and Adler. In addition, the statistical distributions of the parameters are given. The final section of the report contains the recommended formats for the parameters of the various formulae. (author)

  12. Coherence-Resonance Chimeras in a Network of Excitable Elements

    Science.gov (United States)

    Semenova, Nadezhda; Zakharova, Anna; Anishchenko, Vadim; Schöll, Eckehard

    2016-07-01

    We demonstrate that chimera behavior can be observed in nonlocally coupled networks of excitable systems in the presence of noise. This phenomenon is distinct from classical chimeras, which occur in deterministic oscillatory systems, and it combines temporal features of coherence resonance, i.e., the constructive role of noise, and spatial properties of chimera states, i.e., the coexistence of spatially coherent and incoherent domains in a network of identical elements. Coherence-resonance chimeras are associated with alternating switching of the location of coherent and incoherent domains, which might be relevant in neuronal networks.

  13. An absolute nuclear magnetic resonance magnetometer; Magnetometre absolu a resonance magnetique nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Salvi, A. [Commisariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1961-10-15

    After an introduction in which the various work undertaken since the discovery of nuclear magnetic resonance is rapidly reviewed, the author describes briefly In the first chapter three types of NMR magnetometers, giving the advantages and disadvantages of each of them and deducing from this the design of the apparatus having the greatest number of qualities Chapter II is devoted to the crossed coil nuclear oscillator which operates continuously over a wide range (800 gamma). To avoid an error due to a carrying over the frequency, the measurement is carried out using bands of 1000 {gamma}. Chapter III deals with frequency measurements. The author describes an original arrangement which makes possible the frequency-field conversion with an accuracy of {+-} 5 x 10{sup -6}, and the differential measurement between two nuclear oscillators. The report finishes with a conclusion and a few recordings. (author) [French] Apres une introduction rappelant les divers travaux effectues en resonance magnetique nucleaire depuis sa mise en evidence, l'auteur decrit sommairement dans le premier chapitre trois types de magnetometre a R.M.N. enumerant les avantages et les inconvenients de chacun a partir desquels il projet, l'appareillage reunissant le maximum de qualites. Le chapitre II est consacre a l'oscillateur nucleaire a bobines croisees permettant un fonctionnement continu dons une large plage (800 gamma). Pour eviter une erreur due a l'entrainement de frequence, la mesure s'effectue par bandes de 1000 {gamma} chacune. Le chapitre III traite la mesure de frequence. L'auteur expose un montage original permettant la traduction frequence-champ avec une precision egale a {+-} 5.10{sup -6}, et la mesure differentielle entre deux oscillateurs nucleaires. Une conclusion et quelques enregistrements terminent ce travail. (auteur)

  14. Effect of resonance decay on conserved number fluctuations in a hadron resonance gas model

    Science.gov (United States)

    Mishra, D. K.; Garg, P.; Netrakanti, P. K.; Mohanty, A. K.

    2016-07-01

    We study the effect of charged secondaries coming from resonance decay on the net-baryon, net-charge, and net-strangeness fluctuations in high-energy heavy-ion collisions within the hadron resonance gas (HRG) model. We emphasize the importance of including weak decays along with other resonance decays in the HRG, while comparing with the experimental observables. The effect of kinematic cuts on resonances and primordial particles on the conserved number fluctuations are also studied. The HRG model calculations with the inclusion of resonance decays and kinematical cuts are compared with the recent experimental data from STAR and PHENIX experiments. We find good agreement between our model calculations and the experimental measurements for both net-proton and net-charge distributions.

  15. Pyroshock simulation for satellite components using a tunable resonant fixture

    Science.gov (United States)

    Davie, N. T.; Bateman, V. I.

    Aerospace components are often subjected to pyroshock events during flight and deployment, and must be qualified to this frequently severe environment. Laboratory simulation of pyroshock using a mechanically excited resonant fixture, has gained favor at Sandia for testing small (less than 8 inch cube) satellite and weapon components. With this method, each different shock environment required a different resonant fixture that was designed such that it's response reached the environment. A new test method has been developed which eliminates the need to have a different resonant fixture for each test requirement. This is accomplished by means of a tunable resonant fixture that has a response which is adjustable over a wide frequency range. The adjustment of the fixture's response is done in a simple and deterministic way. This report covers the first phase of this research, which includes design conception through fabrication and evaluation of hardware capable of testing components with up to a 10 inch x 10 inch base. This method will ultimately allow the testing of much larger items, perhaps as large as entire small satellites.

  16. Pyroshock simulation for satellite components using a tunable resonant fixture

    Energy Technology Data Exchange (ETDEWEB)

    Davie, N.T.; Bateman, V.I.

    1992-12-31

    Aerospace components are often subjected to pyroshock events during flight and deployment, and must be qualified to this frequently severe environment. Laboratory simulation of pyroshock using a mechanically excited resonant fixture, has gained favor at Sandia for testing small (<8 inch cube) satellite and weapon components. With this method, each different shock environment required a different resonant fixture that was designed such that it`s response retched the environment A new test method has been developed which eliminates the need to have a different resonant fixture for each test requirement This is accomplished by means of a tunable resonant fixture that has a response which is adjustable over a wide frequency range. The adjustment of the fixture`s response is done in a simple and deterministic way. This report covers the first phase of this research, which includes design conception through fabrication and evaluation of hardware capable of testing components with up to a 10 inch {times} 10 inch base. This method will ultimately allow the testing of much larger items, perhaps as large as entire small satellites.

  17. Pyroshock simulation for satellite components using a tunable resonant fixture

    Energy Technology Data Exchange (ETDEWEB)

    Davie, N.T.; Bateman, V.I.

    1992-01-01

    Aerospace components are often subjected to pyroshock events during flight and deployment, and must be qualified to this frequently severe environment. Laboratory simulation of pyroshock using a mechanically excited resonant fixture, has gained favor at Sandia for testing small (<8 inch cube) satellite and weapon components. With this method, each different shock environment required a different resonant fixture that was designed such that it's response retched the environment A new test method has been developed which eliminates the need to have a different resonant fixture for each test requirement This is accomplished by means of a tunable resonant fixture that has a response which is adjustable over a wide frequency range. The adjustment of the fixture's response is done in a simple and deterministic way. This report covers the first phase of this research, which includes design conception through fabrication and evaluation of hardware capable of testing components with up to a 10 inch [times] 10 inch base. This method will ultimately allow the testing of much larger items, perhaps as large as entire small satellites.

  18. Temperature compensation of resonant cavities with a teflon post

    OpenAIRE

    Bará Temes, Francisco Javier

    1982-01-01

    The negative temperature coefficient of E for teflon is used to compensate the frequency drift of a metal cavity due to thermal expansion. An experimental X-band transmission resonator was compensated in this way with a 10 mm teflon post. The results are considered of great interest for the compensation of waveguide millimiter wave oscillators. Peer Reviewed

  19. A Surface Plasmon Resonance Immunobiosensor for Detection of Phytophthora infestans

    DEFF Research Database (Denmark)

    Skottrup, Peter; Frøkiær, Hanne; Hejgaard, Jørn;

    In this study we focused on the development of a Surface Plasmon Resonance (SPR) immunosensor for Phytophthora infestans detection. The fungus-like organism is the cause of potato late blight and is a major problem in potato growing regions of the world. Efficient control is dependent on early...

  20. Cardiovascular magnetic resonance findings in a case of Danon disease

    OpenAIRE

    Kosieradzka Agnieszka; Walczak Ewa; Kuch Marek; Kownacki Lukasz; Piotrowska-Kownacka Dorota; Fidzianska Anna; Krolicki Leszek

    2009-01-01

    Abstract Danon disease is a rare X-linked dominant lysosomal glycogen storage disease that can lead to severe ventricular hypertrophy and heart failure. We report a case of Danon disease with cardiac involvement evaluated with cardiovascular magnetic resonance, including late gadolinium enhancement and perfusion studies.

  1. Euclidean resonance and a new type of nuclear reactions

    CERN Document Server

    Ivlev, B I

    2003-01-01

    The extremely small probability of quantum tunneling through an almost classical potential barrier may become not small under the action of the specially adapted nonstationary field. The tunneling rate has a sharp peak as a function of the particle energy when it is close to the certain resonant value defined by the nonstationary field (Euclidean resonance). Alpha decay of nuclei has a small probability since the alpha particle should tunnel through a very nontransparent Coulomb barrier. The incident proton, due to the Coulomb interaction with the tunneling alpha particle, plays the role of a nonstationary field which may result in Euclidean resonance in tunneling of the alpha particle. At the resonant proton energy, which is of the order of 0.2 Mev, the alpha particle escapes the nucleus and goes to infinity with no influence of the nuclear Coulomb barrier. The process is inelastic since the alpha particle releases energy and the proton gains it. This stimulation of alpha decay by a proton constitutes a new ...

  2. Breakdown of Effective Field Theory for a Gluon Initiated Resonance

    CERN Document Server

    de la Puente, Alejandro

    2016-01-01

    Gauge invariance dictates that a resonance produced from initial state gluons must be produced through a non-renormalizable operator or a loop process. Should such a resonance be discovered, uncovering the dynamics that give rise to its couplings to gluons will be crucial to understanding the nature of the new state. Here we study how the production of this resonance at high transverse momentum in association with one (or more) jets can be used to directly measure the scale of the operator or the mass of the particles in the loop. We use a 750 GeV diphoton resonance as an example application, and we study how the non-renormalizable operator case can be described by a slowly converging effective field theory (EFT) expansion with operators of dimension five and seven. We show that with O(100) events, one can put strong constraints on the scale of the EFT, particularly in theories with strong coupling. We also compare the EFT analysis to that of a UV completion with vector-like quarks, and outline how the mass o...

  3. Stochastic resonance of vortices in a washboard pinning potential

    International Nuclear Information System (INIS)

    Highlights: • The dynamics of Abrikosov vortices in a cosine pinning potential is investigated. • The voltage responses are predicted to demonstrate stochastic resonance. • Experimental parameters for observing stochastic resonance are suggested. - Abstract: In a bistable potential at low temperatures, stochastic resonance can be characterized as a synchronization effect of the hopping mechanism induced by an external periodic stimulus, where synchronization attains a maximum by fine-tuning the forcing frequency close to the relevant switching rate. In this work, we theoretically investigate the nonlinear single-vortex dynamics in a tilted cosine (multistable) washboard pinning potential at nonzero temperature in the presence of dc and ac currents of arbitrary amplitudes and frequency. The conditions for stochastic resonance to appear are derived on the basis of the exact solution of the corresponding Langevin equation for non-interacting vortices in terms of a matrix continued fraction. The nonlinear ac voltage response is analyzed as a function of temperature, dc bias, ac amplitude and frequency, with particular focus on the amplification of the external harmonic signal and its conversion to the third harmonics of the input frequency

  4. Magnetic Resonance Imaging and Magnetic Resonance Spectroscopy Characterize a Rodent Model of Covert Stroke

    Science.gov (United States)

    Herrera, Sheryl Lyn

    Covert stroke (CS) comprises lesions in the brain often associated by risk factors such as a diet high in fat, salt, cholesterol and sugar (HFSCS). Developing a rodent model for CS incorporating these characteristics is useful for developing and testing interventions. The purpose of this thesis was to determine if magnetic resonance (MR) can detect brain abnormalities to confirm this model will have the desired anatomical effects. Ex vivo MR showed brain abnormalities for rats with the induced lesions and fed the HFSCS diet. Spectra acquired on the fixed livers had an average percent area under the fat peak relative to the water peak of (20+/-4)% for HFSCS and (2+/-2)% for control. In vivo MR images had significant differences between surgeries to induce the lesions (p=0.04). These results show that applying MR identified abnormalities in the rat model and therefore is important in the development of this CS rodent model.

  5. Analytical investigation into the resonance frequencies of a curling probe

    Science.gov (United States)

    Arshadi, Ali; Brinkmann, Ralf Peter

    2016-08-01

    The term ‘active plasma resonance spectroscopy’ (APRS) denotes a class of closely related plasma diagnostic methods which utilize the natural ability of plasmas to resonate on or near the electron plasma frequency {ω\\text{pe}} ; an electrical radio frequency signal (in the GHz range) is coupled into the plasma via an antenna or a probe, the spectral response is recorded and a mathematical model is employed to determine plasma parameters such as the plasma density and the electron temperature. The curling probe, recently invented by Liang et al (2011 Appl. Phys. Express 4 066101), is a novel realization of the APRS concept which has many practical advantages. In particular, it can be miniaturized and flatly embedded into the chamber wall, thus allowing the monitoring of plasma processes without contamination nor disturbance. Physically, the curling probe can be understood as a ‘coiled’ form of the hairpin probe (Stenzel 1976 Rev. Sci. Instrum. 47 603). Assuming that the spiralization of the probe has little electrical effect, this paper investigates the characteristcs of a ‘straightened’ curling probe by modeling it as an infinite slot-type resonator that is in direct contact with the plasma. The diffraction of an incident plane wave at the slot is calculated by solving the cold plasma model and Maxwell’s equations simultaneously. The resonance frequencies of the probe are derived and are found to be in good agreement with the numerical results of the probe inventors.

  6. The diphoton resonance as a gravity mediator of dark matter

    CERN Document Server

    Han, Chengcheng; Park, Myeonghun; Sanz, Veronica

    2015-01-01

    We consider the possibility of interpreting the recently reported diphoton excess at 750 GeV as a spin-two massive particle (such as a Kaluza-Klein graviton in warped extra-dimensions) which serves as a mediator to Dark Matter via its gravitational couplings to the dark sector and to the Standard Model (SM). We model non-universal couplings of the resonance to gauge bosons in the SM and to Dark Matter as a function on their localization in the extra dimension. We find that scalar, fermion or vector dark matter can saturate the dark matter relic density by the annihilation of dark matter into a pair of the SM particles or heavy resonances, in agreement with the diphoton resonance signal strength. We check the compatibility of our hypothesis with other searches for the KK graviton. We show that the invisible decay rate of the resonance into a pair of dark matter is subdominant in the region of the correct relic density, hence leading to no constraints from the mono-jet bound at 8 TeV via the gluon coupling. We ...

  7. Strong nonlinear harmonic generation in a PZT/Aluminum resonator

    Energy Technology Data Exchange (ETDEWEB)

    Parenthoine, D; Haumesser, L; Meulen, F Vander; Tran-Huu-Hue, L-P, E-mail: parenthoine@univ-tours.f [University Francois Rabelais of Tours, U 930 Imagerie et Cerveau, CNRS 2448, ENIVL, rue de la Chocolaterie, BP 3410, 41034 Blois (France)

    2009-11-01

    In this work, the extentional vibration mode of a coupled PZT/ Aluminum rod resonator is studied experimentally. Geometrical characteristics of the PZT are its 27 mm length and its 4x4 mm{sup 2} cross section area. The excitation voltage consists in sinusoidal bursts in the frequency range (20-80 kHz). Velocity measurements are performed at both ends of this system, using a laser probe. Strong harmonic distortions in the mechanical response (up to -20 dB with respect to the primary wave amplitude) have been observed. The corresponding input levels are far lower than those which are necessary to observe quadratic second harmonic generation in a free PZT resonator. The strong nonlinear effect can be explained as a super-harmonic resonance of the system due to a specific ratio between the eigen frequencies of the two parts of the resonator. Evolution of fundamental and harmonic responses are observed as a function of input levels, highlighting hysteretic behavior.

  8. Evaluation of toroidal torque by non-resonant magnetic perturbations in tokamaks for resonant transport regimes using a Hamiltonian approach

    CERN Document Server

    Albert, Christopher G; Kapper, Gernot; Kasilov, Sergei V; Kernbichler, Winfried; Martitsch, Andreas F

    2016-01-01

    Toroidal torque generated by neoclassical viscosity caused by external non-resonant, non-axisymmetric perturbations has a significant influence on toroidal plasma rotation in tokamaks. In this article, a derivation for the expressions of toroidal torque and radial transport in resonant regimes is provided within quasilinear theory in canonical action-angle variables. The proposed approach treats all low-collisional quasilinear resonant NTV regimes including superbanana plateau and drift-orbit resonances in a unified way and allows for magnetic drift in all regimes. It is valid for perturbations on toroidally symmetric flux surfaces of the unperturbed equilibrium without specific assumptions on geometry or aspect ratio. The resulting expressions are shown to match existing analytical results in the large aspect ratio limit. Numerical results from the newly developed code NEO-RT are compared to calculations by the quasilinear version of the code NEO-2 at low collisionalities. The importance of the magnetic shea...

  9. Towards a comprehensive model for a resonant nanoelectromechanical system

    International Nuclear Information System (INIS)

    The mass production and very large scale integration (VLSI) of micro/nanoelectromechanical systems (M/NEMS) requires the development and use of accurate models and simulations, which are capable of rapidly evaluating potential designs. Because of the large range of applications that have been proposed for M/NEMS, the most useful models are those that can accurately capture a system’s response under widely varying input and operating conditions. This allows the M/NEMS devices to be treated as well understood circuit components in simulation contexts. It is towards this end that a first-principles based model is proposed for a resonant nanosystem inclusive of an electrostatically-actuated fixed-fixed beam resonator, test equipment and system parasitics. By encoding the algebraic and differential equations which describe the system into circuit components using Verilog-A, an experimental test setup was simulated using Spectre and subsequently compared to experimental results for qualitative validation of the model. The simulation was then used to investigate the behavior of a representative device for a basic input configuration that more closely represents a final-use scenario for the nanoresonator. Discrepancies between the commonly-employed experimental methodology and the practical final-use scenario are discussed and used as a platform to encourage the development of improved experimental methodologies, while also emphasizing the need for robust and accurate system-level models. (paper)

  10. Analyzing a Vibrating Wire Transducer using Coupled Resonator Circuits

    Directory of Open Access Journals (Sweden)

    POP, S.

    2015-08-01

    Full Text Available This paper intends to be an approach on the vibrating wire transducer from the perspective of the necessary rules used for a correct measurement procedure. There are several studies which analyze the vibrating wire transducer as a mechanical system. However, a comparative time-domain analysis between the mechanical and the electrical model is lacking. The transducer analysis is based on a theoretical analysis of the equivalent circuit, on both excitation and response time intervals. The electrical model consists of two magnetic coupled resonating circuits. When connected to an excitation source, there will be an energy transfer from the coil to the wire. The maximum energy transfer will occur at the vibrating wire's frequency of resonance. Using the transient regime analysis, it has been proven that, in the response time interval - when the wire vibrates freely, the current through the circuit that models the wire describes the oscillating movement of the wire. A complex signal is obtained, that contains both coil's and wire's frequencies of resonance, strongly dependent with theirs parasitic elements. The mathematical analysis highlights the similarity between mechanical and electrical model and the procedures in order to determine the wire frequency of resonance from the output signal.

  11. Electron paramagnetic resonance: a powerful tool to support magnetic resonance imaging research.

    Science.gov (United States)

    Danhier, Pierre; Gallez, Bernard

    2015-01-01

    The purpose of this paper is to describe some of the areas where electron paramagnetic resonance (EPR) has provided unique information to MRI developments. The field of application mainly encompasses the EPR characterization of MRI paramagnetic contrast agents (gadolinium and manganese chelates, nitroxides) and superparamagnetic agents (iron oxide particles). The combined use of MRI and EPR has also been used to qualify or disqualify sources of contrast in MRI. Illustrative examples are presented with attempts to qualify oxygen sensitive contrast (i.e. T1 - and T2 *-based methods), redox status or melanin content in tissues. Other areas are likely to benefit from the combined EPR/MRI approach, namely cell tracking studies. Finally, the combination of EPR and MRI studies on the same models provides invaluable data regarding tissue oxygenation, hemodynamics and energetics. Our description will be illustrative rather than exhaustive to give to the readers a flavour of 'what EPR can do for MRI'.

  12. Electron paramagnetic resonance: A new method of quaternary dating

    International Nuclear Information System (INIS)

    Significant progress has occurred in the last years in quaternary geochronology. One of this is the emergence of a new dating approach, the Electron Spin Resonance Method. The aim of this paper is to briefly review the method and discuss some aspects of the work at CBPF. (Author)

  13. A few words about Resonances in the Electroweak Effective Lagrangian

    CERN Document Server

    Rosell, Ignasi; Santos, Joaquin; Sanz-Cillero, Juan Jose

    2015-01-01

    Contrary to a widely spread believe, we have demonstrated that strongly coupled electroweak models including both a light Higgs-like boson and massive spin-1 resonances are not in conflict with experimental constraints on the oblique S and T parameters. We use an effective Lagrangian implementing the chiral symmetry breaking SU(2)_L x SU(2)_R -> SU(2)_{L+R} that contains the Standard Model gauge bosons coupled to the electroweak Goldstones, one Higgs-like scalar state h with mass m_h=126 GeV and the lightest vector and axial-vector resonance multiplets V and A. We have considered the one-loop calculation of S and T in order to study the viability of these strongly-coupled scenarios, being short-distance constraints and dispersive relations the main ingredients of the calculation. Once we have constrained the resonance parameters, we do a first approach to the determination of the low energy constants of the electroweak effective theory at low energies (without resonances). We show this determination in the ca...

  14. Experimental Analysis of Stochastic Resonance in a Duffing System

    Institute of Scientific and Technical Information of China (English)

    WANG Fu-Zhong; CHEN Wei-Shi; QIN Guang-Rong; GUO De-Yong; LIU Jun-Ling

    2003-01-01

    An experimental circuit is used to study the stochastic resonance (SR) phenomena in a Duffing system. The characteristics ofSR are investigated from various aspects by varying all the possible parameters. The deviations between the experimental results and the adiabatic theory are presented.

  15. A Quantum Mechanical Review of Magnetic Resonance Imaging

    CERN Document Server

    Odaibo, Stephen G

    2012-01-01

    In this paper, we review the quantum mechanics of magnetic resonance imaging (MRI). We traverse its hierarchy of scales from the spin and orbital angular momentum of subatomic particles to the ensemble magnetization of tissue. And we review a number of modalities used in the assessment of acute ischemic stroke and traumatic brain injury.

  16. Alternative current harmonics on a resonant tunneling diode

    International Nuclear Information System (INIS)

    The harmonics of forced oscillations on a resonant tunneling diode have been analyzed in the paper. The amplitudes and phases of the harmonics have been obtained as functions of the bias voltage. The dependences of the amplitudes of the harmonics on the amplitude of the external signal have been also analyzed

  17. A few words about resonances in the electroweak effective Lagrangian

    Energy Technology Data Exchange (ETDEWEB)

    Rosell, Ignasi [Departamento de Ciencias Físicas, Matemáticas y de la Computación, Universidad CEU Cardenal Herrera, c/ Sant Bartomeu 55, 46115 Alfara del Patriarca, València (Spain); Pich, Antonio; Santos, Joaquín [Departament de Física Teòrica, IFIC, Universitat de València – CSIC, Apt. Correus 22085, 46071 València (Spain); Sanz-Cillero, Juan José [Departamento de Física Teórica and Instituto Física Teórica, IFT-UAM/CSIC, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid (Spain)

    2016-01-22

    Contrary to a widely spread believe, we have demonstrated that strongly coupled electroweak models including both a light Higgs-like boson and massive spin-1 resonances are not in conflict with experimental constraints on the oblique S and T parameters. We use an effective Lagrangian implementing the chiral symmetry breaking SU (2){sub L} ⊗ SU (2){sub R} → SU (2){sub L+R} that contains the Standard Model gauge bosons coupled to the electroweak Goldstones, one Higgs-like scalar state h with mass m{sub h} = 126 GeV and the lightest vector and axial-vector resonance multiplets V and A. We have considered the one-loop calculation of S and T in order to study the viability of these strongly-coupled scenarios, being short-distance constraints and dispersive relations the main ingredients of the calculation. Once we have constrained the resonance parameters, we do a first approach to the determination of the low energy constants of the electroweak effective theory at low energies (without resonances). We show this determination in the case of the purely Higgsless bosonic Lagrangian.

  18. Resonator design for a visible wavelength free-electron laser [*

    International Nuclear Information System (INIS)

    Design requirements for a visible wavelength free-electron laser being developed at the Accelerator Test Facility at Brookhaven National Laboratory are presented along with predictions of laser performance from 3-D numerical simulations. The design and construction of the optical resonator, its alignment and control systems are also described. 15 refs., 8 figs., 4 tabs

  19. Design of a loop resonator with a split-ring-resonator (SRR) for a human-body coil in 3 T MRI systems

    Science.gov (United States)

    Son, Hyeok Woo; Cho, Young Ki; Kim, Byung Mun; Back, Hyun Man; Yoo, Hyoungsuk

    2016-04-01

    A new radio-frequency (RF) resonator for Nuclear Magnetic Resonance (NMR) imaging at clinical magnetic resonance imaging (MRI) systems is proposed in this paper. An approach based on the effects of the properties of metamaterials in split-ring resonators (SRRs) is used to design a new loop resonator with a SRR for NMR imaging. This loop resonator with a SRR is designed for NMR imaging at 3 T MRI systems. The 3D electromagnetic simulation was used to optimize the design of the proposed RF resonator and analyze it's performance at 3 T MRI systems. The proposed RF resonator provides strong penetrating magnetic fields at the center of the human phantom model, approximately 10%, as compared to the traditional loop-type RF resonator used for NMR imaging at clinical MRI systems. We also designed an 8-channel body coil for human-body NMR imaging by using the proposed loop resonator with a SRR. This body coil also produces more homogeneous and highly penetrating magnetic fields into the human phantom model.

  20. Requirements for a new resonator structure at TRIUMF

    Energy Technology Data Exchange (ETDEWEB)

    Dohan, D.; Dutto, G.; Fong, K.; Laxdal, R.; Pacak, V.; Poirier, R.; Worsham, R.; Zach, M.

    1984-04-01

    The resonator cavity at TRIUMF is unique of its type with its large size (6 x 16 x 0.5 m/sup 3/) and its total containment within the magnetic field. Nine years of successful operation with RF fundamental at beam currents up to 150 ..mu..A have proven the validity of the concept. However, for greater reliability and third harmonic flat-topping a new resonator structure is being designed to incorporate improvements for reduced RF leakage into the beam gap, better alignment, and reduced dee vibration amplitudes. For separated turns at extraction, tolerances of +-80 ppM in voltage and +- 0.12/sup 0/ of third harmonic degrees in the phase jitter between fundamental and third harmonic have to be maintained. This imposes stringent requirements on the mechanical stability of the 3 m long cantilevered resonator panels and on the feedback systems for RF controls. New design criteria in terms of reduced leakage and mechanical stability have been derived from beam orbit calculations, RF cavity computer simulations, and 1:10 scale RF model measurements. The new requirements and the criteria will be discussed in relationship to the data from the present resonator system as measured through a system of voltage probes, RF leakage probes, induction coils and accelerometers.

  1. A double scale fast algorithm for the transient evolution of a resonant tunneling diode

    OpenAIRE

    Ben Abdallah, Naoufel; Faraj, Ali

    2015-01-01

    The simulation of the time-dependent evolution of the resonant tunneling diode is done by a multiscale algorithm exploiting the existence of resonant states. After revisiting and improving the algorithm developed in [N. Ben Abdallah, O. Pinaud, J. Comp. Phys. 213 (2006) 288-310] for the stationary case, the time-dependent problem is dealt with. The wave function is decomposed into a non resonant part and a resonant one. The projection method to compute the resonant part leads to an accurate a...

  2. A study of the main resonances outside the geostationary ring

    CERN Document Server

    Celletti, Alessandra

    2015-01-01

    We investigate the dynamics of satellites and space debris in external resonances, namely in the region outside the geostationary ring. Precisely, we focus on the 1:2, 1:3, 2:3 resonances, which are located at about 66 931.4 km, 87 705.0 km, 55 250.7 km, respectively. Some of these resonances have been already exploited in space missions, like XMM-Newton and Integral. Our study is mainly based on a Hamiltonian approach, which allows us to get fast and reliable information on the dynamics in the resonant regions. Significative results are obtained even by considering just the effect of the geopotential in the Hamiltonian formulation. For objects (typically space debris) with high area-to-mass ratio the Hamiltonian includes also the effect of the solar radiation pressure. In addition, we perform a comparison with the numerical integration in Cartesian variables, including the geopotential, the gravitational attraction of Sun and Moon, and the solar radiation pressure. We implement some simple mathematical tools...

  3. A random subsynchronous resonance in a turbine generator set

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, J.I.; Zhan, T.S. [Kao Yuan Univ., Kaohsiung, Taiwan (China). Dept. of Electronic Engineering; Wu, R.C. [I-Shou Univ., Kaohsiung, Taiwan (China). Dept. of Electrical Engineering

    2006-07-01

    The largest load in a power system can be attributed to the electrical arc furnace (EAF). This paper investigated the torsional vibrations in turbine-generator shafts and blades subject to real and reactive power variations from a large-scale EAF plant. The study was conducted since electromechanical interactions between electrical loads and turbine-generator are rarely examined. The torsional impact of electrical disturbances on turbine-generator shafts and blades impose considerably high stresses on turbine shafts and blades and even cause fatigue damage such as network fault. Most excitations are focused on large disturbances since small disturbances are not immediately noticed. However, the cumulative long-term fatigue damaging effect should not be ignored when the small disturbances are sustained and even resonant. The paper presented simulation results of these investigations in the form of typical time responses. The dynamic load fed by real and reactive power consumption data measured at metal-out-fit (MOF) of an EAF plant was conducted in order to precisely model the stochastic behavior of an EAF load. The load flow for the one-machine infinite-bus system incorporating such an EAF load was also conducted. It was concluded that the transient power fluctuation of the load was randomly dramatic and that most of the frequencies of the induced voltage flicker, generator delivering power and even electromagnetic torque were subsynchronous. Therefore, such a continued stochastic disturbance could impose random subsynchronous resonant stresses on turbine mechanisms. 8 refs., 4 tabs., 8 figs.

  4. Spoof surface plasmon Fabry-Perot open resonators in a surface-wave photonic crystal

    CERN Document Server

    Gao, Zhen; Xu, Hongyi; Zhang, Youming; Zhang, Baile

    2016-01-01

    We report on the proposal and experimental realization of a spoof surface plasmon Fabry-Perot (FP) open resonator in a surface-wave photonic crystal. This surface-wave FP open resonator is formed by introducing a finite line defect in a surface-wave photonic crystal. The resonance frequencies of the surface-wave FP open resonator lie exactly within the forbidden band gap of the surface-wave photonic crystal and the FP open resonator uses this complete forbidden band gap to concentrate surface waves within a subwavelength cavity. Due to the complete forbidden band gap of the surface-wave photonic crystal, a new FP plasmonic resonance mode that exhibits monopolar features which is missing in traditional FP resonators and plasmonic resonators is demonstrated. Near-field response spectra and mode profiles are presented in the microwave regime to characterize properties of the proposed FP open resonator for spoof surface plasmons.

  5. Interpreting the behavior of a quarter-wave transmission line resonator in a magnetized plasma

    International Nuclear Information System (INIS)

    The quarter wave resonator immersed in a strongly magnetized plasma displays two possible resonances occurring either below or above its resonance frequency in vacuum, fo. This fact was demonstrated in our recent articles [G. S. Gogna and S. K. Karkari, Appl. Phys. Lett. 96, 151503 (2010); S. K. Karkari, G. S. Gogna, D. Boilson, M. M. Turner, and A. Simonin, Contrib. Plasma Phys. 50(9), 903 (2010)], where the experiments were carried out over a limited range of magnetic fields at a constant electron density, ne. In this paper, we present the observation of dual resonances occurring over the frequency scan and find that ne calculated by considering the lower resonance frequency is 25%–30% smaller than that calculated using the upper resonance frequency with respect to fo. At a given magnetic field strength, the resonances tend to shift away from fo as the background density is increased. The lower resonance tends to saturate when its value approaches electron cyclotron frequency, fce. Interpretation of these resonance conditions are revisited by examining the behavior of the resonance frequency response as a function of ne. A qualitative discussion is presented which highlights the practical application of the hairpin resonator for interpreting ne in a strongly magnetized plasma

  6. Resonant tunneling in a Luttinger liquid for arbitrary barrier transmission

    OpenAIRE

    Huegle, S.; Egger, R.

    2003-01-01

    A numerically exact dynamical quantum Monte Carlo approach has been developed and applied to transport through a double barrier in a Luttinger liquid with arbitrary transmission. For strong transmission, we find broad Fabry-Perot Coulomb blockade peaks, with a lineshape parametrized by a single parameter, but at sufficiently low temperatures, non-Lorentzian universal lineshapes characteristic of coherent resonant tunneling emerge, even for strong interactions. For weak transmission, our data ...

  7. Circularly polarized dielectric resonator antenna excited by a conformal wire

    OpenAIRE

    Khamas, S.K.

    2008-01-01

    A conformal spiral wire has been used to feed a dielectric resonator antenna to obtain a circular polarization. The parameters of the spiral have been optimized numerically so that minimum axial ratio (AR) and return losses are achieved. The method of moments (MoM) has been used in the analysis and the results have been validated against those from a commercial software package with a good agreement.

  8. Fast Neutron Resonance Radiography in a Pulsed Neutron Beam

    OpenAIRE

    Dangendorf, V.; Laczko, G; Kersten, C.; Jagutzki, O.; Spillmann, U

    2003-01-01

    The feasibility of performing fast neutron resonance radiography at the PTB accelerator facility is studied. A neutron beam of a broad spectral distribution is produced by a pulsed 13 MeV deuterium beam hitting a thick Be target. The potential of 3 different neutron imaging detectors with time-of flight capability are investigated. The applied methods comprise wire chambers with hydrogenous converter layers and a fast plastic scintillator with different optical readout schemes. We present the...

  9. Implementation of a Biaxial Resonant Fatigue Test Method on a Large Wind Turbine Blade

    Energy Technology Data Exchange (ETDEWEB)

    Snowberg, D.; Dana, S.; Hughes, S.; Berling, P.

    2014-09-01

    A biaxial resonant test method was utilized to simultaneously fatigue test a wind turbine blade in the flap and edge (lead-lag) direction. Biaxial resonant blade fatigue testing is an accelerated life test method utilizing oscillating masses on the blade; each mass is independently oscillated at the respective flap and edge blade resonant frequency. The flap and edge resonant frequency were not controlled, nor were they constant for this demonstrated test method. This biaxial resonant test method presented surmountable challenges in test setup simulation, control and data processing. Biaxial resonant testing has the potential to complete test projects faster than single-axis testing. The load modulation during a biaxial resonant test may necessitate periodic load application above targets or higher applied test cycles.

  10. Vortex properties of a resonant superfluid

    International Nuclear Information System (INIS)

    The properties of a vortex in a rotating superfluid Fermi gas are studied in the unitary limit. A phenomenological approach based on Ginzburg-Landau theory is developed for this purpose. The density profiles, including those of the normal fluid and superfluid, are obtained at various temperatures and rotation frequencies. The superfluid and normal fluid densities can be identified from the angular momentum density. The total free energy and angular momentum of the vortex are also obtained

  11. Triadic instability of a non-resonant precessing fluid cylinder

    CERN Document Server

    Lagrange, R; Eloy, C

    2015-01-01

    Flows forced by a precessional motion can exhibit instabilities of crucial importance, whether they concern the fuel of a flying object or the liquid core of a telluric planet. So far, stability analyses of these flows have focused on the special case of a resonant forcing. Here, we address the instability of the flow inside a precessing cylinder in the general case. We first show that the base flow forced by the cylinder precession is a superposition of a vertical or horizontal shear flow and an infinite sum of forced modes. We then perform a linear stability analysis of this base flow by considering its triadic resonance with two free Kelvin modes. Finally, we derive the amplitude equations of the free Kelvin modes and obtain an expression of the instability threshold and growth rate.

  12. Validity - a matter of resonant experience

    DEFF Research Database (Denmark)

    Revsbæk, Line

    across researcher’s past experience from the case study and her own life. The autobiographic way of analyzing conventional interview material is exemplified with a case of a junior researcher researching newcomer innovation of others, drawing on her own experience of being newcomer in work community...

  13. A reflex resonance model of vocal vibrato

    Science.gov (United States)

    Titze, Ingo R.; Story, Brad; Smith, Marshall; Long, Russel

    2002-05-01

    A reflex mechanism with a long latency (>40 ms) is implicated as a plausible cause of vocal vibrato. At least one pair of agonist-antagonist muscles that can change vocal-fold length is needed, such as the cricothyroid muscle paired with the thyroarytenoid muscle, or the cricothyroid muscle paired with the lateral cricoarytenoid muscle or a strap muscle. Such an agonist-antagonist muscle pair can produce negative feedback instability in vocal-fold length with this long reflex latency, producing oscillations on the order of 5-7 Hz. It is shown that singers appear to increase the gain in the reflex loop to cultivate the vibrato, which grows out of a spectrum of 0-15-Hz physiologic tremors in raw form.

  14. Analysis of a Non-resonant Ultrasonic Levitation Device

    Science.gov (United States)

    Andrade, Marco A. B.; Pérez, Nicolás; Adamowski, Julio C.

    In this study, a non-resonant configuration of ultrasonic levitation device is presented, which is formed by a small diameter ultrasonic transducer and a concave reflector. The influence of different levitator parameters on the levitation performance is investigated by using a numerical model that combines the Gor'kov theory with a matrix method based on the Rayleigh integral. In contrast with traditional acoustic levitators, the non-resonant ultrasonic levitation device allows the separation distance between the transducer and the reflector to be adjusted continually, without requiring the separation distance to be set to a multiple of half-wavelength. It is also demonstrated, both numerically and experimentally, that the levitating particle can be manipulated by maintaining the transducer in a fixed position in space and moving the reflector in respect to the transducer.

  15. Magnetic resonance imaging of a phakomatous choristoma

    Energy Technology Data Exchange (ETDEWEB)

    Otto, Josephin; Sorge, Ina [Leipzig University Hospital, Department of Pediatric Radiology, Leipzig (Germany); Horn, Lars-Christian [Leipzig University Hospital, Institute of Pathology, Leipzig (Germany); Sterker, Ina [Leipzig University Hospital, Department of Ophthalmology, Leipzig (Germany)

    2015-10-15

    Phakomatous choristoma is a rare congenital benign tumour in the inferomedial eyelid or orbit that is thought to be of lenticular anlage origin. We describe the MRI findings in an infant boy with histopathologically confirmed phakomatous choristoma. (orig.)

  16. Magnetization reversal in a ferromagnetic circular dot under current induced resonant excitation

    International Nuclear Information System (INIS)

    A magnetic vortex core in a ferromagnetic circular dot can be resonantly excited by a spin-polarized AC current at the eigenfrequency determined by the confining potential. We studied the magnetic properties of the dot in its dynamical state with a vortex core on resonance as well as off resonance. Magnetoresistance measurements under the AC current revealed that the annihilation field of the vortex core is reduced in the resonance state compared to the off-resonance state. This may be due to the additional energy accompanying the resonant motion

  17. Magnetic Resonance Imaging of Benign Cardiac Masses: A Pictorial Essay

    Directory of Open Access Journals (Sweden)

    Thomas J Ward

    2013-01-01

    Full Text Available The differential diagnosis for a cardiac mass includes primary and metastatic neoplasms. While primary cardiac tumors are rare, metastatic disease to the heart is a common finding in cancer patients. Several "tumor-like" processes can mimic a true cardiac neoplasm with accurate diagnosis critical at guiding appropriate management. We present a pictorial essay of the most common benign cardiac masses and "mass-like" lesions with an emphasis on magnetic resonance imaging features.

  18. Magnetic Resonance Imaging (MRI) Simulation on a Grid Computing Architecture

    OpenAIRE

    Benoit-Cattin, Hugues; Bellet, Fabrice; Montagnat, Johan; Odet, Christophe

    2010-01-01

    In this paper, we present the implementation of a Magnetic Resonance Imaging (MRI) simulator on a GRID computing architecture. The simulation process is based on the resolution of Bloch equation [1] in a 3D space. The computation kernel of the simulator is distributed to the grid nodes using MPICH-G2 [2]. The results presented show that simulation of 3D MRI data is achieved with a reasonable cost which gives new perspectives to MRI simulations usage.

  19. Diphoton resonance from a new strong force

    Science.gov (United States)

    Georgi, Howard; Nakai, Yuichiro

    2016-10-01

    We explore a "partial unification" model that a new strong gauge group is combined with the ordinary color and hypercharge gauge groups. The VEV responsible for the combination is of the order of the S U (2 )×U (1 ) breaking scale, but the coupling of the new physics to standard model particles is suppressed by the strong interaction of the new gauge group. This simple extension of the standard model has a rich phenomenology, including composite particles of the new confining gauge interaction, a coloron and a Z' which are rather weakly coupled to standard model particles, and massive vector bosons charged under both the ordinary color and hypercharge gauge groups and the new strong gauge group. The new scalar glueball could be produced by gluon fusion and decay into two photons, both through loops of the new massive vector bosons. The simplest version of the model has some issues: the massive vector bosons are stable and the coloron and the Z' are strongly constrained by search data. An extension of the model to include additional fermions with the new gauge coupling, though not as simple and elegant, can address both issues and more. It allows the massive vector boson to decay into a colorless, neutral state that could be a candidate of the dark matter. And the coloron and Z' can decay dominantly into the new fermions, completely changing the search bounds. If the massive vector bosons are still long lived, they could form new bound states, "vector bosoniums" with additional interesting phenomenology. The model is an explicit example of how new physics at small scales could be hidden by strong interactions.

  20. A Wideband Circularly Polarized Pixelated Dielectric Resonator Antenna

    Science.gov (United States)

    Trinh-Van, Son; Yang, Youngoo; Lee, Kang-Yoon; Hwang, Keum Cheol

    2016-01-01

    The design of a wideband circularly polarized pixelated dielectric resonator antenna using a real-coded genetic algorithm (GA) is presented for far-field wireless power transfer applications. The antenna consists of a dielectric resonator (DR) which is discretized into 8 × 8 grid DR bars. The real-coded GA is utilized to estimate the optimal heights of the 64 DR bars to realize circular polarization. The proposed antenna is excited by a narrow rectangular slot etched on the ground plane. A prototype of the proposed antenna is fabricated and tested. The measured −10 dB reflection and 3 dB axial ratio bandwidths are 32.32% (2.62–3.63 GHz) and 14.63% (2.85–3.30 GHz), respectively. A measured peak gain of 6.13 dBic is achieved at 3.2 GHz. PMID:27563897

  1. Design and construction of a nuclear magnetic resonator circuit

    International Nuclear Information System (INIS)

    It is described the operation of a feedback circuit that it using the nuclear resonance phenomena and that covers a broad sweeping interval in frequency with a minimum adjustment of the circuit elements and it produces an appropriate nuclear absorption for a sign relation at reasonable noise. The circuit is an oscillator amplifier modulated that it is based its sensibility and stability in an inductive-capacitive arrangement in parallel and always operate in resonant condition, in such a way that the quality factor of Q arrangement has been very elevated. Thus when the nuclear absorption occurs it is producing a fall of Q effective. The oscillation amplitude is controllable and it maintains in a convenient value over the operation interval using control by feedback. The circuit uses a configuration 'Auto dyne Hop kin' that it suffers as a follower of inductive charge, which have the main characteristic of to cause a negative resistance that it appears through the tuning circuit. It is introduced a control for feedback via two trajectories, the first by differential pair for to maintain the amplitude level in RF and the second for to stability a band wide interval in the modulation condition. It is necessary since the RF signal value must have a value to excite the specimen nucleus without to carry to saturate it and that the permanence in the absorption region was appropriate. Between applications of the nuclear magnetic resonance phenomena we have the magnetic fields measurements, physicochemical molecular properties studies, training and medical instrumentation. (Author)

  2. Breathers in a locally resonant granular chain with precompression

    Science.gov (United States)

    Liu, Lifeng; James, Guillaume; Kevrekidis, Panayotis; Vainchtein, Anna

    2016-09-01

    We study a locally resonant granular material in the form of a precompressed Hertzian chain with linear internal resonators. Using an asymptotic reduction, we derive an effective nonlinear Schrödinger (NLS) modulation equation. This, in turn, leads us to provide analytical evidence, subsequently corroborated numerically, for the existence of two distinct types of discrete breathers related to acoustic or optical modes: (a) traveling bright breathers with a strain profile exponentially vanishing at infinity and (b) stationary and traveling dark breathers, exponentially localized, time-periodic states mounted on top of a non-vanishing background. The stability and bifurcation structure of numerically computed exact stationary dark breathers is also examined. Stationary bright breathers cannot be identified using the NLS equation, which is defocusing at the upper edges of the phonon bands and becomes linear at the lower edge of the optical band.

  3. Coupling a thermal atomic vapor to an integrated ring resonator

    CERN Document Server

    Ritter, Ralf; Pernice, Wolfram; Kübler, Harald; Pfau, Tilman; Löw, Robert

    2016-01-01

    Strongly interacting atom-cavity systems within a network with many nodes constitute a possible realization for a quantum internet which allows for quantum communication and computation on the same platform. To implement such large-scale quantum networks, nanophotonic resonators are promising candidates because they can be scalably fabricated and interconnected with waveguides and optical fibers. By integrating arrays of ring resonators into a vapor cell we show that thermal rubidium atoms above room temperature can be coupled to photonic cavities as building blocks for chip-scale hybrid circuits. Although strong coupling is not yet achieved in this first realization, our approach provides a key step towards miniaturization and scalability of atom-cavity systems.

  4. Correlations between resonances in a statistical scattering model

    CERN Document Server

    Gorin, T; Müller, M; Rotter, I; Seligman, T H

    1997-01-01

    The distortion of the regular motion in a quantum system by its coupling to the continuum of decay channels is investigated. The regular motion is described by means of a Poissonian ensemble. We focus on the case of only few channels K<10. The coupling to the continuum induces two main effects, due to which the distorted system differs from a chaotic system (described by a Gaussian ensemble): 1. The width distribution for large coupling becomes broader than the corresponding $\\chi^2_K$ distribution in the GOE case. 2. Due to the coupling to the continuum, correlations are induced not only between the positions of the resonances but also between positions and widths. These correlations remain even in the strong coupling limit. In order to explain these results, an asymptotic expression for the width distribution is derived for the one channel case. It relates the width of a trapped resonance state to the distance between its two neighboring levels.

  5. Correlations between resonances in a statistical scattering model

    Energy Technology Data Exchange (ETDEWEB)

    Gorin, T. [Technische Univ. Dresden (Germany). Inst. fuer Theoretische Physik]|[Forschungszentrum Rossendorf e.V. (FZR), Dresden (Germany). Inst. fuer Kern- und Hadronenphysik; Dittes, F.M. [Forschungszentrum Rossendorf e.V. (FZR), Dresden (Germany). Inst. fuer Kern- und Hadronenphysik; Mueller, M. [Centro Internacional de Ciencias, Cuernavaca (Mexico); Rotter, I. [Technische Univ. Dresden (Germany). Inst. fuer Theoretische Physik]|[Forschungszentrum Rossendorf e.V. (FZR), Dresden (Germany). Inst. fuer Kern- und Hadronenphysik; Seligman, T.H. [Centro Internacional de Ciencias, Cuernavaca (Mexico)

    1997-01-01

    The distortion of the regular motion in a quantum system by its coupling to the continuum of decay channels is investigated. The regular motion is described by means of a Poissonian ensemble. We focus on the case of only few channels K < 10. The coupling to the continuum induces two main effects, due to which the distorted system differs from a chaotic system (described by a Gaussian ensemble): 1. The width distribution for large coupling becomes broader than the corresponding {chi}{sup 2}{sub K} distribution in the GOE case. 2. Due to the coupling to the continuum, correlations are induced not only between the positions of the resonances but also between positions and widths. These correlations remain even in the strong coupling limit. In order to explain these results, an asymptotic expression for the width distribution is derived for the one channel case. It relates the width of a trapped resonance state to the distance between its two neighboring levels. (orig.)

  6. Optical modulation in a resonant tunneling relaxation oscillator

    CERN Document Server

    Figueiredo, J M L; Boyd, A R; Ironside, C N

    1999-01-01

    We report high speed optical modulation in a resonant tunneling relaxation oscillator consisting of a resonant tunneling diode (RTD) integrated with a unipolar optical waveguide and incorporated in a package with a coplanar waveguide transmission line. When appropriately biased, the RTD can provide wide-bandwidth electrical gain. For wavelengths near the material band-edge, small changes of the applied voltage give rise to large, high-speed electro-absorption modulation of the light. We have observed optical modulation at frequencies up to 14 GHz, associated with sub harmonic injection locking of the RTD oscillation at the fundamental mode of the coplanar transmission line, as well as generation of 33 ps optical pulses due to relaxation oscillation.

  7. Resonant X-ray emission with a standing wave excitation.

    Science.gov (United States)

    Ruotsalainen, Kari O; Honkanen, Ari-Pekka; Collins, Stephen P; Monaco, Giulio; Moretti Sala, Marco; Krisch, Michael; Hämäläinen, Keijo; Hakala, Mikko; Huotari, Simo

    2016-01-01

    The Borrmann effect is the anomalous transmission of x-rays in perfect crystals under diffraction conditions. It arises from the interference of the incident and diffracted waves, which creates a standing wave with nodes at strongly absorbing atoms. Dipolar absorption of x-rays is thus diminished, which makes the crystal nearly transparent for certain x-ray wave vectors. Indeed, a relative enhancement of electric quadrupole absorption via the Borrmann effect has been demonstrated recently. Here we show that the Borrmann effect has a significantly larger impact on resonant x-ray emission than is observable in x-ray absorption. Emission from a dipole forbidden intermediate state may even dominate the corresponding x-ray spectra. Our work extends the domain of x-ray standing wave methods to resonant x-ray emission spectroscopy and provides means for novel spectroscopic experiments in d- and f-electron systems.

  8. Spin injection in a ferromagnet/resonant tunneling diode heterostructure

    Institute of Scientific and Technical Information of China (English)

    Jin Bao; Fang Wan; Yu Wang; Xiaoguang Xu; Yong Jiang

    2008-01-01

    The spin transport property of a ferromagnet (FM)/insulator (I)/resonant tunneling diode (RTD) heterostructure was stud-ied. The transmission coefficient and spin polarization in a multilayered heterostructure was calculated by a Scbr(o)dinger wave equa-tion. An Airy function formalism approach was used to solve this equation. Based on the transfer matrix approach, the transmittivity of the structure was determined as a function of the Feimi energy and other parameters. The result shows that the spin polarization induced by the structure oscillates with the increasing Fermi energy of the FM layer. While the thickness of the RTD is reduced, the resonant peaks become broad. In the heterostructure, the spin polarization reaches as high as 40% and can be easily controlled by the external bias voltage.

  9. Resonant X-ray emission with a standing wave excitation

    Science.gov (United States)

    Ruotsalainen, Kari O.; Honkanen, Ari-Pekka; Collins, Stephen P.; Monaco, Giulio; Moretti Sala, Marco; Krisch, Michael; Hämäläinen, Keijo; Hakala, Mikko; Huotari, Simo

    2016-01-01

    The Borrmann effect is the anomalous transmission of x-rays in perfect crystals under diffraction conditions. It arises from the interference of the incident and diffracted waves, which creates a standing wave with nodes at strongly absorbing atoms. Dipolar absorption of x-rays is thus diminished, which makes the crystal nearly transparent for certain x-ray wave vectors. Indeed, a relative enhancement of electric quadrupole absorption via the Borrmann effect has been demonstrated recently. Here we show that the Borrmann effect has a significantly larger impact on resonant x-ray emission than is observable in x-ray absorption. Emission from a dipole forbidden intermediate state may even dominate the corresponding x-ray spectra. Our work extends the domain of x-ray standing wave methods to resonant x-ray emission spectroscopy and provides means for novel spectroscopic experiments in d- and f-electron systems. PMID:26935531

  10. A model realizing inverse seesaw and resonant leptogenesis

    CERN Document Server

    Aoki, Mayumi; Takahashi, Ryo

    2015-01-01

    We construct a model realizing the inverse seesaw mechanism. The model has two types of gauge singlet fermions in addition to right-handed neutrinos. A required Majorana mass scale (keV scale) for generating the light active neutrino mass in the conventional inverse seesaw can be naturally explained by a "seesaw" mechanism between the two singlet fermions in our model. We find that our model can decrease the magnitude of hierarchy among mass parameters by $\\mathcal{O}(10^4)$ from that in the conventional inverse seesaw model. We also show that a successful resonant leptogenesis occurs for generating the baryon asymmetry of the universe in our model. The desired mass degeneracy for the resonant leptogenesis can also be achieved by the "seesaw" between the two singlet fermions.

  11. Hodological resonance, hodological variance, psychosis and schizophrenia: A hypothetical model

    Directory of Open Access Journals (Sweden)

    Paul Brian eLawrie Birkett

    2011-07-01

    Full Text Available Schizophrenia is a disorder with a large number of clinical, neurobiological, and cognitive manifestations, none of which is invariably present. However it appears to be a single nosological entity. This article considers the likely characteristics of a pathology capable of such diverse consequences. It is argued that both deficit and psychotic symptoms can be manifestations of a single pathology. A general model of psychosis is proposed in which the informational sensitivity or responsivity of a network ("hodological resonance" becomes so high that it activates spontaneously, to produce a hallucination, if it is in sensory cortex, or another psychotic symptom if it is elsewhere. It is argued that this can come about because of high levels of modulation such as those assumed present in affective psychosis, or because of high levels of baseline resonance, such as those expected in deafferentation syndromes associated with hallucinations, for example, Charles Bonnet. It is further proposed that schizophrenia results from a process (probably neurodevelopmental causing widespread increases of variance in baseline resonance; consequently some networks possess high baseline resonance and become susceptible to spontaneous activation. Deficit symptoms might result from the presence of networks with increased activation thresholds. This hodological variance model is explored in terms of schizo-affective disorder, transient psychotic symptoms, diathesis-stress models, mechanisms of antipsychotic pharmacotherapy and persistence of genes predisposing to schizophrenia. Predictions and implications of the model are discussed. In particular it suggests a need for more research into psychotic states and for more single case-based studies in schizophrenia.

  12. A broad 750 GeV diphoton resonance? Not alone

    CERN Document Server

    Roig, P

    2016-01-01

    The existence of a possible resonance in the diphoton channel with mass of 750 GeV is still under study and will be hopefully clarified this summer. If confirmed with a large width, it will be difficult to accommodate within weakly interacting beyond Standard Model theories, hinting a composite scenario. By means of forward sum-rules for $\\gamma\\gamma$ and $gg$ scattering we show that a spin-0 resonance with mass of the order of the TeV and a sizable $\\gamma\\gamma$ or $gg$ partial width -of the order of a few GeV- must be accompanied by higher spin resonances with $J_R\\geq 2$ with similar properties, as expected in strongly coupled extensions of the Standard Model or, alternatively, in higher dimensional deconstructed duals. Furthermore, independently of whether the 750 GeV candidate is a scalar or a tensor, the large contribution to the forward sum-rules in the referred scenario implies the presence of states in the spectrum with $J_R\\geq 2$, being these high spin particles a manifestation of new extra-dimen...

  13. Active plasma resonance spectroscopy: a functional analytic description

    Science.gov (United States)

    Lapke, M.; Oberrath, J.; Mussenbrock, T.; Brinkmann, R. P.

    2013-04-01

    The term ‘active plasma resonance spectroscopy’ denotes a class of diagnostic methods which employ the ability of plasmas to resonate on or near the plasma frequency. The basic idea dates back to the early days of discharge physics: a signal in the GHz range is coupled to the plasma via an electrical probe; the spectral response is recorded, and then evaluated with a mathematical model to obtain information on the electron density and other plasma parameters. In recent years, the concept has found renewed interest as a basis of industry compatible plasma diagnostics. This paper analyzes the diagnostic technique in terms of a general description based on functional analytic (or Hilbert Space) methods which hold for arbitrary probe geometries. It is shown that the response function of the plasma-probe system can be expressed as a matrix element of the resolvent of an appropriately defined dynamical operator. A specialization of the formalism to a symmetric probe design is given, as well as an interpretation in terms of a lumped circuit model consisting of series resonance circuits. We present ideas for an optimized probe design based on geometric and electrical symmetry.

  14. Magnetic resonance force microscopy and a solid state quantum computer.

    Energy Technology Data Exchange (ETDEWEB)

    Pelekhov, D. V. (Denis V.); Martin, I. (Ivar); Suter, A. (Andreas); Reagor, D. W. (David W.); Hammel, P. C. (P. Chris)

    2001-01-01

    A Quantum Computer (QC) is a device that utilizes the principles of Quantum Mechanics to perform computations. Such a machine would be capable of accomplishing tasks not achievable by means of any conventional digital computer, for instance factoring large numbers. Currently it appears that the QC architecture based on an array of spin quantum bits (qubits) embedded in a solid-state matrix is one of the most promising approaches to fabrication of a scalable QC. However, the fabrication and operation of a Solid State Quantum Computer (SSQC) presents very formidable challenges; primary amongst these are: (1) the characterization and control of the fabrication process of the device during its construction and (2) the readout of the computational result. Magnetic Resonance Force Microscopy (MRFM)--a novel scanning probe technique based on mechanical detection of magnetic resonance-provides an attractive means of addressing these requirements. The sensitivity of the MRFM significantly exceeds that of conventional magnetic resonance measurement methods, and it has the potential for single electron spin detection. Moreover, the MRFM is capable of true 3D subsurface imaging. These features will make MRFM an invaluable tool for the implementation of a spin-based QC. Here we present the general principles of MRFM operation, the current status of its development and indicate future directions for its improvement.

  15. The multipole resonance probe: characterization of a prototype

    Energy Technology Data Exchange (ETDEWEB)

    Lapke, Martin; Oberrath, Jens; Brinkmann, Ralf Peter; Mussenbrock, Thomas [Lehrstuhl fuer Theoretische Elektrotechnik, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); Schulz, Christian; Rolfes, Ilona [Lehrstuhl fuer Hochfrequenzsysteme, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); Storch, Robert; Musch, Thomas [Lehrstuhl fuer Elektronische Schaltungstechnik, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); Styrnoll, Tim; Awakowicz, Peter [Lehrstuhl fuer Allgemeine Elektrotechnik und Plasmatechnik, Ruhr Universitaet Bochum, D-44780 Bochum (Germany); Zietz, Christian [Institut fuer Hochfrequenztechnik und Funksysteme, Leibniz Universitaet Hannover, D-30167 Hannover (Germany)

    2011-08-15

    The multipole resonance probe (MRP) was recently proposed as an economical and industry compatible plasma diagnostic device (Lapke et al 2008 Appl. Phys. Lett. 93 051502). This communication reports the experimental characterization of a first MRP prototype in an inductively coupled argon/nitrogen plasma at 10 Pa. The behavior of the device follows the predictions of both an analytical model and a numerical simulation. The obtained electron densities are in excellent agreement with the results of Langmuir probe measurements. (brief communication)

  16. Angular characteristics of a multimode fiber surface plasmon resonance sensor

    CERN Document Server

    Tan, Zhixin; Li, Xuejin; Chen, Yuzhi; Hong, Xueming; Fan, Ping

    2015-01-01

    In this paper the angular characteristics of a multimode fiber SPR sensor are investigated theoretically. By separating the contributions of beams incident at different angles, a compact model is presented to predict the shift of the resonance wavelength with respect to the angle and the environmental refractive index. The result suggests that the performance of conventional fiber SPR sensors can be substantially improved by optimizing the incident angle.

  17. Clinical applications of nuclear magnetic resonance spectroscopy: a review

    International Nuclear Information System (INIS)

    The advantages and present limitations of the clinical applications of nuclear magnetic resonance spectroscopy are reviewed in outline, with passing references to skeletal muscular studies, in particular a group of children with advanced Duchenne dystrophy, and the applications to the study of cerebral metabolism of neonates, excised kidneys, biopsy studies of breast and axillary lymph node samples, and NMR spectroscopy performed during chemotherapy of a secondary rhabdomyosarcoma in the skin. (U.K.)

  18. Magnetic resonance imaging of patients wearing a surgical traction halo.

    Science.gov (United States)

    Hua, J; Fox, R A

    1996-01-01

    Magnetic resonance images of patients wearing a surgical halo may have unacceptable artifacts if the halo has a conductive loop structure. This study shows that the observed artifacts are predominantly due to eddy currents generated in the halo by switching field gradients, and that these artifacts can be substantially reduced by adjusting the phase encoding direction in MRI sequences so that it is parallel to the axis of the halo. PMID:8851441

  19. Electric field switching in a resonant tunneling diode electroabsorption modulator

    OpenAIRE

    Figueiredo, J.M.L.; Ironside, C. N.; Stanley, C.R.

    2005-01-01

    The basic mechanism underlying electric field switching produced by a resonant tunnelling diode (RTD) is analysed and the theory compared with experimental results; agreement to within 12% is achieved. The electro-absorption modulator (EAM) device potential of this effect is explored in an optical waveguide configuration. It is shown that a RTD-EAM can provide significant absorption coefficient change, via the Franz-Keldysh effect, at appropriate optical communication wavelengths around 1550 ...

  20. Coralling a distant planet with extreme resonant Kuiper belt objects

    CERN Document Server

    Malhotra, Renu; Wang, Xianyu

    2016-01-01

    The four longest period Kuiper belt objects have orbital periods close to small integer ratios with each other. A hypothetical planet with orbital period $\\sim$17,117 years, semimajor axis $\\sim$665 AU, would have N/1 and N/2 period ratios with these four objects. The orbital geometries and dynamics of resonant orbits constrain the orbital plane, the orbital eccentricity and the mass of such a planet, as well as its current location in its orbital path.

  1. A Search for Heavy Resonances in the Dilepton Channel

    Directory of Open Access Journals (Sweden)

    Hayden Daniel

    2012-06-01

    Full Text Available There are many extensions to the Standard Model of particle physics which predict the addition of a U(1 symmetry, and/or extra spatial dimensions, which give rise to new high mass resonances such as the Z′ and Randall-Sundrum graviton. The LHC provides a unique opportunity to explore the TeV scale where these phenomena may become apparent, and can be searched for using the precision tracking and high energy resolution calorimetry of the ATLAS detector. This poster presents the search for high mass resonances in the dilepton channel, and was conducted with an integrated luminosity of 1.08/1.21 fb−1 in the dielectron/dimuon channel respectively, at a centre of mass energy √s = 7 TeV.

  2. A resonant ionization laser ion source at ORNL

    Science.gov (United States)

    Liu, Y.; Stracener, D. W.

    2016-06-01

    Multi-step resonance laser ionization has become an essential tool for the production of isobarically pure radioactive ion beams at the isotope separator on-line (ISOL) facilities around the world. A resonant ionization laser ion source (RILIS) has been developed for the former Holifield Radioactive Ion Beam Facility (HRIBF) of Oak Ridge National Laboratory. The RILIS employs a hot-cavity ion source and a laser system featuring three grating-tuned and individually pumped Ti:Sapphire lasers, especially designed for stable and simple operation. The RILIS has been installed at the second ISOL production platform of former HRIBF and has successfully provided beams of exotic neutron-rich Ga isotopes for beta decay studies. This paper reports the features, advantages, limitations, and on-line and off-line performance of the RILIS.

  3. Fabrication of a Resonant Photoacoustic Cell for Samples Study

    Directory of Open Access Journals (Sweden)

    J.C. Kapil

    2004-04-01

    Full Text Available Nondestructive treatment of a sample in photoacoustic spectroscopy is helpful in the study of thermal and optical properties of ice and snow. In the present study, a  low-temperature resonant photoacoustic cell, based on Helmholtz resonator model, has been designed and fabricated for the study of samples like ice or snow. Its performance has also been studied using carbon black as a standard sample and various other samples like water, ice, glass, plexi-glass, polycarbonate, etc. Thermal diffusivity of ice, water, and many other transparent materials has been determined by varying chopping frequency and recording corresponding phase changes in the photoacoustic signal. The results obtained are in good agreement with those predicted by Rosencwaig-Gersho (R-G' theory.

  4. Novel kinematics from a custodially protected diphoton resonance

    Science.gov (United States)

    Collins, Jack H.; Csáki, Csaba; Dror, Jeff A.; Lombardo, Salvator

    2016-06-01

    We study a simple, well-motivated model based on a custodial symmetry which describes the tree-level production of a 750 GeV diphoton resonance from a decay of a singly produced vector-like quark. The model has several novel features. The identification of the resonance as an SU(2 ) R triplet provides a symmetry explanation for suppression of its decays to h h , W W , and g g . Moreover, the ratio of the 13 TeV to 8 TeV cross sections can be larger than single production of a 750 GeV resonance, reaching ratios of up to 7 for TeV scale vectorlike quark masses. This eliminates any tension between the results from Run I and Run II diphoton searches. Lastly, we study the kinematics of our signal and conclude that the new production mechanism is consistent with available experimental distributions in large regions of parameter space but, depending on the mass of the new vectorlike quarks, can be differentiated from the background with more statistics.

  5. Quantum resonance catastrophe for conductance through a periodically driven barrier

    Science.gov (United States)

    Thuberg, Daniel; Reyes, Sebastián A.; Eggert, Sebastian

    2016-05-01

    We consider the quantum conductance in a tight-binding chain with a locally applied potential which is oscillating in time. The steady state for such a driven impurity can be calculated exactly for any energy and applied potential using the Floquet formalism. The resulting transmission has a nontrivial, nonmonotonic behavior depending on incoming momentum, driving frequency, and the strength of the applied periodic potential. Hence there is an abundance of tuning possibilities, which allows finding the resonances of total reflection for any choice of incoming momentum and periodic potential. Remarkably, this implies that even for an arbitrarily small infinitesimal impurity potential it is always possible to find a resonance frequency at which there is a catastrophic breakdown of the transmission T =0 . The points of zero transmission are closely related to the phenomenon of Fano resonances at dynamically created bound states in the continuum. The results are relevant for a variety of one-dimensional systems where local AC driving is possible, such as quantum nanodot arrays, ultracold gases in optical lattices, photonic crystals, or molecular electronics.

  6. Optically tunable Fano resonance in a grating-based Fabry-Perot cavity-coupled microring resonator on a silicon chip.

    Science.gov (United States)

    Zhang, Weifeng; Li, Wangzhe; Yao, Jianping

    2016-06-01

    A grating-based Fabry-Perot (FP) cavity-coupled microring resonator on a silicon chip is reported to demonstrate an all-optically tunable Fano resonance. In the device, an add-drop microring resonator (MRR) is employed, and one of the two bus waveguides is replaced by an FP cavity consisting of two sidewall Bragg gratings. By choosing the parameters of the gratings, the resonant mode of the FP cavity is coupled to one of the resonant modes of the MRR. Due to the coupling between the resonant modes, a Fano resonance with an asymmetric line shape resulted. Measurement results show a Fano resonance with an extinction ratio of 22.54 dB, and a slope rate of 250.4 dB/nm is achieved. A further study of the effect of the coupling on the Fano resonance is performed numerically and experimentally. Thanks to the strong light-confinement capacity of the MRR and the FP cavity, a strong two-photon absorption induced nonlinear thermal-optic effect resulted, which is used to tune the Fano resonance optically.

  7. A possible proton pygmy resonance in 17Ne

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The low-lying electric dipole strengths in proton-rich nuclei 17F and 17Ne, which can be produced at HIRFL-CSR in Lanzhou, are investigated. In the framework of the covariant density functional theory the self-consistent relativistic Hartree Bogoliubov model and the relativistic quasiparticle random phase approximation with the NL3 parameter set and Gogny pairing interaction are adopted in the calculations. A pronounced dipole peak appears below 10 MeV in17Ne, but does not occur in 17F. The prop erties of this low-lying E1 excitation in 17Ne are studied, which may correspond to a proton pygmy resonance with different characteristics from those of giant dipole resonance.

  8. Fano resonance and persistent current of a quantum ring

    International Nuclear Information System (INIS)

    We investigate electron transport and persistent current of a quantum ring weakly attached to current leads. Assuming there is direct coupling (weakly or strongly) between two leads, electrons can transmit by the inter-lead coupling or tunneling through the quantum ring. The interference between the two paths yields asymmetric Fano line shape for conductance. In presence of interior magnetic flux, there is persistent current along the ring with narrow resonance peaks. The positions of the conductance resonances and the persistent current peaks correspond to the quasibound levels of the closed ring. This feature is helpful to determine the energy spectrum of the quantum ring. Our results show that the proposed setup provides a tunable Fano system

  9. Evaluation of toroidal torque by non-resonant magnetic perturbations in tokamaks for resonant transport regimes using a Hamiltonian approach

    Science.gov (United States)

    Albert, Christopher G.; Heyn, Martin F.; Kapper, Gernot; Kasilov, Sergei V.; Kernbichler, Winfried; Martitsch, Andreas F.

    2016-08-01

    Toroidal torque generated by neoclassical viscosity caused by external non-resonant, non-axisymmetric perturbations has a significant influence on toroidal plasma rotation in tokamaks. In this article, a derivation for the expressions of toroidal torque and radial transport in resonant regimes is provided within quasilinear theory in canonical action-angle variables. The proposed approach treats all low-collisional quasilinear resonant neoclassical toroidal viscosity regimes including superbanana-plateau and drift-orbit resonances in a unified way and allows for magnetic drift in all regimes. It is valid for perturbations on toroidally symmetric flux surfaces of the unperturbed equilibrium without specific assumptions on geometry or aspect ratio. The resulting expressions are shown to match the existing analytical results in the large aspect ratio limit. Numerical results from the newly developed code NEO-RT are compared to calculations by the quasilinear version of the code NEO-2 at low collisionalities. The importance of the magnetic shear term in the magnetic drift frequency and a significant effect of the magnetic drift on drift-orbit resonances are demonstrated.

  10. Magnetic Resonance Imaging: A Wealth of Cardiovascular Information

    OpenAIRE

    Shah, Sangeeta; Chryssos, Emanuel D.; Parker, Hugh

    2009-01-01

    Cardiac magnetic resonance imaging is a relatively new noninvasive imaging modality that provides insight into multiple facets of the human myocardium not available by other imaging modalities. This one test allows for the assessment of ventricular and valvular function, ischemic and nonischemic cardiomyopathies, congenital heart disease, and cardiac tumors. It has been coined by many as “one-stop shopping.” As with any imaging modality, it is important to understand not only the indications ...

  11. Visualization of subsurface nanoparticles in a polymer matrix using resonance tracking atomic force acoustic microscopy and contact resonance spectroscopy

    Science.gov (United States)

    Kimura, Kuniko; Kobayashi, Kei; Yao, Atsushi; Yamada, Hirofumi

    2016-10-01

    A visualization technique of subsurface features with a nanometer-scale spatial resolution is strongly demanded. Some research groups have demonstrated the visualization of subsurface features using various techniques based on atomic force microscopy. However, the imaging mechanisms have not yet been fully understood. In this study, we demonstrated the visualization of subsurface Au nanoparticles buried in a polymer matrix 900 nm from the surface using two techniques; i.e., resonance tracking atomic force acoustic microscopy and contact resonance spectroscopy. It was clarified that the subsurface features were visualized by the two techniques as the area with a higher contact resonance frequency and a higher Q-factor than those in the surrounding area, which suggests that the visualization is realized by the variation of the contact stiffness and damping of the polymer matrix due to the existence of the buried nanoparticles.

  12. Resonance control for a cw [continuous wave] accelerator

    International Nuclear Information System (INIS)

    A resonance-control technique is described that has been successfully applied to several cw accelerating structures built by the Los Alamos National Laboratory for the National Bureau of Standards and for the University of Illinois. The technique involves sensing the rf fields in an accelerating structure as well as the rf power feeding into the cavity and, then, using the measurement to control the resonant frequency of the structure by altering the temperature of the structure. The temperature of the structure is altered by adjusting the temperature of the circulating cooling water. The technique has been applied to continuous wave (cw) side-coupled cavities only but should have applications with most high-average-power accelerator structures. Some additional effort would be required for pulsed systems

  13. QND Measurements in a Resonant Cavity-QED System

    Science.gov (United States)

    Chen, Zilong; Bohnet, Justin G.; Dai; Thompson, James K.

    2010-03-01

    We demonstrate QND measurements on an ensemble of 10^6 ^87Rb atoms. Quantum state-dependent populations are determined at the projection noise level by measurements of the collective Vacuum Rabi Splitting for the resonantly coupled atom-cavity system. The splitting is measured by simultaneously scanning the frequency of two probes across the two transmission resonances and phase coherently detecting the full IQ response of the reflected electric fields. Measurement back-action imposes AC Stark shifts on the atoms, resulting in a reduction of the Ramsey fringe contrast due to inhomogeneity in the probe-atom coupling. We show that the spin-echo sequences that will be needed to achieve atomic spin-squeezing on the Rb clock transition also strongly suppress these AC stark shifts. The remaining probe-induced decoherence is close to the fundamental limit imposed by free space scattering of the probe photons.

  14. Resonance Recombination Model: A Dynamical Framework for Hadronization

    CERN Document Server

    Ravagli, L; Rapp, R

    2008-01-01

    We investigate the consequences of space-momentum correlations in quark phase-space distributions for coalescence processes at the hadronization transition. Thus far it has been proved difficult to reconcile such correlations with the empirically observed constituent quark number scaling (CQNS) at the Relativistic Heavy-Ion Collider (RHIC). To address this problem we combine our earlier developed quark recombination model with quark phase-space distributions computed from relativistic Langevin simulations in an expanding Quark-Gluon Plasma (QGP). Hadronization is based on resonance formation within a Boltzmann equation which recovers thermal equilibrium and obeys energy conservation in the quark coalescence process, while the fireball background is adjusted to hydrodynamic simulations of semi-central Au-Au collisions at RHIC. The interactions of quarks in the QGP are modeled using leading-order perturbative QCD augmented by effective Lagrangians with resonances which smoothly merge into hadronic states formed...

  15. The resonant interaction of a submarine's wake with a stratified fluid

    OpenAIRE

    Kowalewski, Joseph A.

    1993-01-01

    Approved for public release; distribution is unlimited Through the use of asymptotic and perturbation methods, this thesis presents a theoretical study of the flow of a stratified fluid over variable topography as a model of the resonant interaction of a submarine's wake with a stratified fluid. Such resonant interactions may be able to produce significant upstream disturbances. The long time solution obtained in our model exhibits growth in time for the resonant case, indicating that perh...

  16. Partial Averaging and Resonance Trapping in a Restricted Three-Body System

    OpenAIRE

    Haghighipour, Nader

    2001-01-01

    Based on the value of the orbital eccentricity of a particle and also its proximity to the exact resonant orbit in a three-body system, the Pendulum Approximation (Dermott & Murray 1983) or the Second Fundamental Model of Resonance (Andoyer 1903; Henrard & Lemaitre 1983) are commonly used to study the motion of that particle near its resonance state. In this paper, we present the method of partial averaging as an analytical approach to study the dynamical evolution of a body near a resonance....

  17. Combining synaptic and cellular resonance in a feed-forward neuronal network

    OpenAIRE

    Jonathan D Drover; Tohidi, Vahid; Bose, Amitabha; Nadim, Farzan

    2007-01-01

    We derive a mathematical theory to explain the subthreshold resonance response of a neuron to synaptic input. The theory shows how a neuron combines information from its intrinsic resonant properties with those of the synapse to determine the neuron’s generalized resonance response. Our results show that the maximal response of a postsynaptic neuron can lie between the preferred intrinsic frequency of the neuron and the synaptic resonance frequency. We compare our theoretical results to paral...

  18. Electron cyclotron resonance heating in a short cylindrical plasma system

    Indian Academy of Sciences (India)

    Vipin K Yadav; D Bora

    2004-09-01

    Electron cyclotron resonance (ECR) plasma is produced and studied in a small cylindrical system. Microwave power is delivered by a CW magnetron at 2.45 GHz in TE10 mode and launched radially to have extraordinary (X) wave in plasma. The axial magnetic field required for ECR in the system is such that the first two ECR surfaces ( = 875.0 G and = 437.5 G) reside in the system. ECR plasma is produced with hydrogen with typical plasma density e as 3.2 × 1010 cm-3 and plasma temperature e between 9 and 15 eV. Various cut-off and resonance positions are identified in the plasma system. ECR heating (ECRH) of the plasma is observed experimentally. This heating is because of the mode conversion of X-wave to electron Bernstein wave (EBW) at the upper hybrid resonance (UHR) layer. The power mode conversion efficiency is estimated to be 0.85 for this system. The experimental results are presented in this paper.

  19. Resonance fluorescence of a trapped three-level atom

    CERN Document Server

    Bienert, M; Morigi, G; Bienert, Marc; Merkel, Wolfgang; Morigi, Giovanna

    2003-01-01

    We investigate theoretically the spectrum of resonance fluorescence of a harmonically trapped atom, whose internal transitions are $\\Lambda$--shaped and driven at two-photon resonance by a pair of lasers, which cool the center--of--mass motion. For this configuration, photons are scattered only due to the mechanical effects of the quantum interaction between light and atom. We study the spectrum of emission in the final stage of laser--cooling, when the atomic center-of-mass dynamics is quantum mechanical and the size of the wave packet is much smaller than the laser wavelength (Lamb--Dicke limit). We use the spectral decomposition of the Liouville operator of the master equation for the atomic density matrix and apply second order perturbation theory. We find that the spectrum of resonance fluorescence is composed by two narrow sidebands -- the Stokes and anti-Stokes components of the scattered light -- while all other signals are in general orders of magnitude smaller. For very low temperatures, however, th...

  20. A coupling model for amplified spontaneous emission in laser resonators

    International Nuclear Information System (INIS)

    The competition between amplified spontaneous emission (ASE) and main laser in solid-state laser resonators is investigated both theoretically and experimentally. A coupled model using the spatial volume integral instead of the Monte Carlo type raytrace technique is proposed to depict ASE in the laser resonators. This model is able to evaluate all possible reflections at both the polishing surface and the diffusive side, to calculate ASE for an inhomogeneous gain distribution, and to include the spectral correction. An experiment is carefully designed to verify the theoretical model and to investigate the distinct physical properties caused by the coupling between ASE and the laser oscillations. The experimental data exhibit an excellent agreement with the theoretical predictions. According to that model, we confirm that ASE in thin-disk lasers can be characterized approximately by the product of the threshold gain of the resonator and the diameter of the disks, as laser modes are highly overlapped with the pumping beam. Theoretical evaluation shows that the scattering characteristic of the disk side impacts on ASE significantly. Furthermore, we point out that ASE decreases output laser power by affecting threshold pumping power, while slope efficiency is not changed by ASE. This observation provides us with a simple way to estimate the decrease of the optical efficiency by ASE. (paper)

  1. The dynamic mechanical characteristics of a resonating microbridge mass-flow sensor

    NARCIS (Netherlands)

    Geijselaers, H.J.M.; Tijdeman, H.

    1991-01-01

    This paper gives an explanation of the dynamic mechanical behaviour of a resonating microbridge mass-flow sensor. A rise in the average temperature of the bridge initially results in a reduction of the resonance frequency. Upon further temperature rise, a reversal occurs and the resonance frequency

  2. Tunability of resonance frequencies in a superconducting microwave resonator by using SrTiO sub 3 ferroelectric films

    CERN Document Server

    Sok, J; Lee, E H

    1998-01-01

    An applied dc voltage varies the dielectric constant of ferroelectric SrTiO sub 3 films. A tuning mechanism for superconducting microwave resonators was realized by using the variation in the dielectric constant of SrTiO sub 3 films. In order to estimate the values of the capacitance, C, and the loss tangent, tan delta, of SrTiO sub 3 ferroelectric capacitors, we used high-temperature superconducting microwave resonators which were composed of two ports, two poles, and dc bias circuits at the zero-field points. SrTiO sub 3 ferroelectric capacitors successfully controlled the resonant frequency of the resonator. Resonant frequencies of 3.98 GHz and 4.20 GHz were measured at bias voltages of 0 V and 50 V which correspond to capacitance values of 0.94 pF and 0.7pF, respectively. The values of the loss tangent, tan delta sub e sub f sub f , obtained in this measurements, were about 0.01.

  3. Encapsulation of a fiber taper coupled microtoroid resonator in a polymer matrix

    OpenAIRE

    Monifi, Faraz; Ozdemir, Sahin Kaya; Friedlein, Jacob; Yang, Lan

    2013-01-01

    We encapsulated a high-quality (Q) factor optical whispering gallery mode (WGM) microtoroid resonator together with its side coupled fiber taper inside a low refractive index polymer, achieving a final Q higher than 10^7. Packaging provides stable resonator-fiber taper coupling, long-term maintenance of high-Q, a protective layer against contaminants, and portability to microtoroid resonator based devices. We tested the robustness of the packaged device under various conditions and demonstrat...

  4. Encapsulation of a fiber taper coupled microtoroid resonator in a polymer matrix

    CERN Document Server

    Monifi, Faraz; Friedlein, Jacob; Yang, Lan

    2013-01-01

    We encapsulated a high-quality (Q) factor optical whispering gallery mode (WGM) microtoroid resonator together with its side coupled fiber taper inside a low refractive index polymer, achieving a final Q higher than 10^7. Packaging provides stable resonator-fiber taper coupling, long-term maintenance of high-Q, a protective layer against contaminants, and portability to microtoroid resonator based devices. We tested the robustness of the packaged device under various conditions and demonstrated its capability for thermal sensing.

  5. Creating a zero-order resonator using an optical surface transformation

    CERN Document Server

    Sun, F; He, S

    2015-01-01

    A novel zero-order resonator has been designed by an optical surface transformation (OST) method. The resonator proposed here has many novel features. Firstly, the mode volume can be very small (e.g. in the subwavelength scale). Secondly, the resonator is open (no reflecting walls are utilized) and resonant effects can be found in a continuous spectrum (i.e. a continuum of eigenmodes). Thirdly, we only need one homogenous medium to realize the proposed resonator. The shape of the resonator can be a ring structure of arbitrary shape. In addition to the natural applications (e.g. optical storage) of an optical resonator, we also suggest some other applications of our novel optical open resonator (e.g. power combination, squeezing electromagnetic energy in the free space).

  6. Fano resonance in a normal metal/ferromagnet-quantum dot-superconductor device

    Science.gov (United States)

    Li, Lin; Cao, Zhan; Luo, Hong-Gang; Zhang, Fu-Chun; Chen, Wei-Qiang

    2015-11-01

    We investigate theoretically the Andreev transport through a quantum dot strongly coupled with a normal metal/ferromagnet and a superconductor (N/F-QD-S), in which the interplay between the Kondo resonance and the Andreev bound states (ABSs) has not been clearly clarified yet. Here we show that the interference between the Kondo resonance and the ABSs modifies seriously the line shape of the Kondo resonance, which manifests as a Fano resonance. The ferromagnetic lead with spin polarization induces an effective field, which leads to splitting of both the Kondo resonance and the ABSs. The spin polarization together with the magnetic field applied provides an alternative way to tune the line shape of the Kondo resonances, which is dependent of the relative positions of the Kondo resonance and the ABSs. These results indicate that the interplay between the Kondo resonance and the ABSs can significantly affect the Andreev transport, which could be tested by experiments.

  7. A Generalized Approach for the Steady-State Analysis of Dual-Bridge Resonant Converters

    OpenAIRE

    Gao-Yuan Hu; Xiaodong Li; Bo-Yue Luan

    2014-01-01

    In this paper, a dual-bridge DC/DC resonant converter with a generalized series and parallel resonant tank is analyzed. A general approach based on Fundamental Harmonic Approximation is used to find the universal steady-state solutions. The analysis results for particular resonant tank configurations are exemplified with several typical resonant tank configurations respectively. The corresponded soft-switching conditions are discussed too. To illustrate the usefulness of the generalized appro...

  8. Phase transitions in trajectories of a superconducting single-electron transistor coupled to a resonator.

    Science.gov (United States)

    Genway, Sam; Garrahan, Juan P; Lesanovsky, Igor; Armour, Andrew D

    2012-05-01

    Recent progress in the study of dynamical phase transitions has been made with a large-deviation approach to study trajectories of stochastic jumps using a thermodynamic formalism. We study this method applied to an open quantum system consisting of a superconducting single-electron transistor, near the Josephson quasiparticle resonance, coupled to a resonator. We find that the dynamical behavior shown in rare trajectories can be rich even when the mean dynamical activity is small, and thus the formalism gives insights into the form of fluctuations. The structure of the dynamical phase diagram found from the quantum-jump trajectories of the resonator is studied, and we see that sharp transitions in the dynamical activity may be related to the appearance and disappearance of bistabilities in the state of the resonator as system parameters are changed. We also demonstrate that for a fast resonator, the trajectories of quasiparticles are similar to the resonator trajectories. PMID:23004718

  9. Engineering a resonant nanocoating for an optical refractive index sensor

    Science.gov (United States)

    Bialiayeu, A.; Ianoul, A.; Albert, J.

    2014-03-01

    We proposing to boost the performance of refractive index sensors based on the tilted fiber Bragg grating (TFBG) structure by resonant coupling of small spherical nanoparticles to the TFBG resonances. The optimal choice of nanoparticle parameters is discussed.

  10. Squeezing of Quantum Noise of Motion in a Micromechanical Resonator.

    Science.gov (United States)

    Pirkkalainen, J-M; Damskägg, E; Brandt, M; Massel, F; Sillanpää, M A

    2015-12-11

    A pair of conjugate observables, such as the quadrature amplitudes of harmonic motion, have fundamental fluctuations that are bound by the Heisenberg uncertainty relation. However, in a squeezed quantum state, fluctuations of a quantity can be reduced below the standard quantum limit, at the cost of increased fluctuations of the conjugate variable. Here we prepare a nearly macroscopic moving body, realized as a micromechanical resonator, in a squeezed quantum state. We obtain squeezing of one quadrature amplitude 1.1±0.4  dB below the standard quantum limit, thus achieving a long-standing goal of obtaining motional squeezing in a macroscopic object. PMID:26705631

  11. All-optical 10 Gb/s AND logic gate in a silicon microring resonator

    DEFF Research Database (Denmark)

    Xiong, Meng; Lei, Lei; Ding, Yunhong;

    2013-01-01

    An all-optical AND logic gate in a single silicon microring resonator is experimentally demonstrated at 10 Gb/s with 50% RZ-OOK signals. By setting the wavelengths of two intensity-modulated input pumps on the resonances of the microring resonator, field-enhanced four-wave mixing with a total input...

  12. Linewidth broadening and emission saturation of a resonantly excited quantum dot monitored via an off-resonant cavity mode

    DEFF Research Database (Denmark)

    Ulhaq, A.; Ates, Serkan; Weiler, S.;

    2010-01-01

    We report on the robustness of a detuned mode channel for reading out the relevant s-shell properties of a resonantly excited coupled quantum dot (QD) in a pillar microcavity. The line broadening of the QD s-shell is “monitored” by the mode signal with high conformity to the directly measured QD ...

  13. Particle manipulation by a non-resonant acoustic levitator

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Marco A. B., E-mail: marcobrizzotti@gmail.com [Institute of Physics, University of São Paulo, CP 66318, 05314-970 São Paulo (Brazil); Pérez, Nicolás [Centro Universitario de Paysandú, Universidad de la República, Ruta 3 km 363, 60000 Paysandú (Uruguay); Adamowski, Julio C. [Department of Mechatronics and Mechanical Systems Engineering, Escola Politécnica, University of São Paulo, Av. Mello Moraes, 2231, 05508-030 São Paulo (Brazil)

    2015-01-05

    We present the analysis of a non-resonant acoustic levitator, formed by an ultrasonic transducer and a concave reflector. In contrast to traditional levitators, the geometry presented herein does not require the separation distance between the transducer and the reflector to be a multiple of half wavelength. The levitator behavior is numerically predicted by applying a numerical model to calculate the acoustic pressure distribution and the Gor'kov theory to obtain the potential of the acoustic radiation force that acts on a levitated particle. We also demonstrate that levitating particles can be manipulated by controlling the reflector position while maintaining the transducer in a fixed position.

  14. Particle manipulation by a non-resonant acoustic levitator

    Science.gov (United States)

    Andrade, Marco A. B.; Pérez, Nicolás; Adamowski, Julio C.

    2015-01-01

    We present the analysis of a non-resonant acoustic levitator, formed by an ultrasonic transducer and a concave reflector. In contrast to traditional levitators, the geometry presented herein does not require the separation distance between the transducer and the reflector to be a multiple of half wavelength. The levitator behavior is numerically predicted by applying a numerical model to calculate the acoustic pressure distribution and the Gor'kov theory to obtain the potential of the acoustic radiation force that acts on a levitated particle. We also demonstrate that levitating particles can be manipulated by controlling the reflector position while maintaining the transducer in a fixed position.

  15. Electron Transport Through a Quantum Wire with a Side-Coupled Quantum Dot:Fano Resonance

    Institute of Scientific and Technical Information of China (English)

    熊永建; 贺舟波

    2004-01-01

    The Fano resonance of a quantum wire (QW) with a side-coupled quantum dot (QD) is investigated. The QD has multilevel and is in the Coulomb blockade regime. We show that there are two aspects in contribution to asymmetric Fano dip line shape of conductance: (1) the quantum interference between the resonant level and non-resonant levels, (2) the asymmetric electron occupation of levels in the two sides of a resonant level in the QD. The smearing of the asymmetry of the dip structure with the increasing temperature is partially attributed to fluctuation of electron state in the QD.

  16. Method of fabricating a whispering gallery mode resonator

    Science.gov (United States)

    Savchenkov, Anatoliy A. (Inventor); Matkso, Andrey B. (Inventor); Iltchenko, Vladimir S. (Inventor); Maleki, Lute (Inventor)

    2011-01-01

    A method of fabricating a whispering gallery mode resonator (WGMR) is provided. The WGMR can be fabricated from a particular material, annealed, and then polished. The WGMR can be repeatedly annealed and then polished. The repeated polishing of the WGMR can be carried out using an abrasive slurry. The abrasive slurry can have a predetermined, constant grain size. Each subsequent polishing of the WGMR can use an abrasive slurry having a grain size that is smaller than the grain size of the abrasive slurry of the previous polishing iteration.

  17. Fast Neutron Resonance Radiography in a Pulsed Neutron Beam

    CERN Document Server

    Dangendorf, V; Kersten, C; Jagutzki, O; Spillmann, U

    2003-01-01

    The feasibility of performing fast neutron resonance radiography at the PTB accelerator facility is studied. A neutron beam of a broad spectral distribution is produced by a pulsed 13 MeV deuterium beam hitting a thick Be target. The potential of 3 different neutron imaging detectors with time-of flight capability are investigated. The applied methods comprise wire chambers with hydrogenous converter layers and a fast plastic scintillator with different optical readout schemes. We present the neutron facility, the imaging methods employed and results obtained. in beam experiments where samples of carbon rods with various length and diameter were imaged to study resolution and sensitivity of the method.

  18. Brillouin Lasing with a CaF_2 Whispering Gallery Mode Resonator

    CERN Document Server

    Grudinin, Ivan S; Maleki, Lute

    2008-01-01

    Stimulated Brillouin scattering with both pump and Stokes beams in resonance with whispering gallery modes of an ultra high Q CaF_2 resonator is demonstrated for the first time. The resonator is pumped with 1064 nm light and has a Brillouin lasing threshold of 3.5 microwatt. Potential applications include optical generation of microwaves and sensitive gyros.

  19. Teaching the Concept of Resonance with the Help of a Classical Guitar

    Science.gov (United States)

    Kasar, M. Kaan; Yurumezoglu, Kemal; Sengoren, Serap Kaya

    2012-12-01

    Resonance refers to the vibrations of larger amplitude that are produced under the effect of a harmonic driving force. Although resonance is an essential concept behind many events happening in nature, students usually have difficulty in learning and explaining the phenomenon. Various demonstrations are carried out in physics classes to clarify the concept of resonance.2-6

  20. Observation of a high-confinement regime in a tokamak plasma with ion cyclotron resonance heating

    Science.gov (United States)

    Steinmetz, K.; Noterdaeme, J.-M.; Wagner, F.; Wesner, F.; Bäumler, J.; Becker, G.; Bosch, H. S.; Brambilla, M.; Braun, F.; Brocken, H.; Eberhagen, A.; Fritsch, R.; Fussmann, G.; Gehre, O.; Gernhardt, J.; v. Gierke, G.; Glock, E.; Gruber, O.; Haas, G.; Hofmann, J.; Hofmeister, F.; Izvozchikov, A.; Janeschitz, G.; Karger, F.; Keilhacker, M.; Klüber, O.; Kornherr, M.; Lackner, K.; Lisitano, G.; van Mark, E.; Mast, F.; Mayer, H. M.; McCormick, K.; Meisel, D.; Mertens, V.; Müller, E. R.; Murmann, H.; Niedermeyer, H.; Poschenrieder, W.; Puri, S.; Rapp, H.; Röhr, H.; Ryter, F.; Schmitter, K.-H.; Schneider, F.; Setzensack, C.; Siller, G.; Smeulders, P.; Söldner, F.; Speth, E.; Steuer, K.-H.; Vollmer, O.; Wedler, H.; Zasche, D.

    1987-01-01

    The H mode in ion cyclotron-resonance-heated plasmas has been investigated with and without additional neutral beam injection. Ion cyclotron-resonance heating can cause the transition into a high-confinement regime (H mode) in combination with beam heating. The H mode, however, has also been realized-for the first time-with ion cyclotron-resonance heating alone in the D (H)-hydrogen minority scheme at an absorbed rf power of 1.1 MW.

  1. Measurement of interaction energy near a Feshbach resonance in a 6Li Fermi gas

    OpenAIRE

    Bourdel, T; Cubizolles, J.; Khaykovich, L.; Magalhaes, K. M. F.; Kokkelmans, S. J. J. M. F.; G. V. Shlyapnikov; Salomon, C

    2003-01-01

    We investigate the strongly interacting regime in an optically trapped $^6$Li Fermi mixture near a Feshbach resonance. The resonance is found at $800(40) $G in good agreement with theory. Anisotropic expansion of the gas is interpreted by collisional hydrodynamics. We observe an unexpected and large shift ($80 $G) between the resonance peak and both the maximum of atom loss and the change of sign of the interaction energy.

  2. Baryon resonances from a novel fat-link fermion action

    CERN Document Server

    Melnitchouk, W; Bonnet, F D R; Coddington, P D; Leinweber, D B; Williams, A G; Zanotti, J M; Zhang, J B; Lee, F X

    2002-01-01

    We present first results for masses of positive and negative parity excited baryons in lattice QCD using an O(a^2) improved gluon action and a Fat Link Irrelevant Clover (FLIC) fermion action in which only the irrelevant operators are constructed with fat links. The results are in agreement with earlier calculations of N^* resonances using improved actions and exhibit a clear mass splitting between the nucleon and its chiral partner, even for the Wilson fermion action. The results also indicate a splitting between the lowest J^P = 1/2^- states for the two standard nucleon interpolating fields.

  3. STM-Induced Hydrogen Desorption via a Hole Resonance

    DEFF Research Database (Denmark)

    Stokbro, Kurt; Thirstrup, C.; Sakurai, M.;

    1998-01-01

    We report STM-induced desorption of H from Si(100)-H(2 X 1) at negative sample bias. The desorption rate exhibits a power-law dependence on current and a maximum desorption rate at -7 V. The desorption is explained by vibrational heating of H due to inelastic scattering of tunneling holes...... with the Si-H 5 sigma hole resonance. The dependence of desorption rate on current and bias is analyzed using a novel approach for calculating inelastic scattering, which includes the effect of the electric field between tip and sample. We show that the maximum desorption rate at -7 V is due to a maximum...

  4. Atomic force microscope characterization of a resonating nanocantilever

    DEFF Research Database (Denmark)

    Abadal, G.; Davis, Zachary James; Borrise, X.;

    2003-01-01

    An atomic force microscope (AFM) is used as a nanometer-scale resolution tool for the characterization of the electromechanical behaviour of a resonant cantilever-based mass sensor. The cantilever is actuated electrostatically by applying DC and AC voltages from a driver electrode placed closely ...... and of the oscillation amplitude on the frequency of the AC voltage is measured by this technique and the results are fitted by a simple non-linear electromechanical model. (C) 2003 Elsevier Science B.V. All rights reserved....

  5. Resonant cavity operation of a virtual cathode oscillator

    International Nuclear Information System (INIS)

    Gigawatt level virtual cathode sources have been proposed for several applications. These include microwave weapons and drivers for high-energy particle accelerators. Both of these require a microwave source with very high power output that is controllable in frequency and phase. A conventional virtual cathode oscillator will not meet these requirements. The addition of a resonant cavity surrounding the oscillating virtual cathode either alone or pumped with a low-power injection signal, causing it to operate as an amplifier, could greatly influence the performance of this type of source making it more practical for accelerator and weapon applications. The progress on an experiment to test these concepts will be discussed

  6. A New Wideband Circularly Polarized Dielectric Resonator Antenna

    OpenAIRE

    M Khalily; Kamarudin, M. R.; Mokayef, M.; Sh. Danesh; Ghahferokhi, S. E. A.

    2014-01-01

    A wideband and compact circularly polarized (CP) C-shaped dielectric resonator antenna (DRA) is presented. The proposed C-shaped DR is excited by a simple stripe line connected to a coplanar waveguide (CPW) feeding line. The C-shaped DRA is circularly polarized with 19% axial ratio (AR) bandwidth. It is found that the CP bandwidth can be expanded by using a narrow short circuit strip. The final design achieves CP with 50% AR bandwidth. The proposed circularly polarized DRA (CPDRA) with good r...

  7. Magnification of photonic crystal fluorescence enhancement via TM resonance excitation and TE resonance extraction on a dielectric nanorod surface

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Hsin-Yu; Cunningham, Brian T [Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, 1406 W Green Street, Urbana, IL 61801 (United States); Zhang Wei [Department of Material Science and Engineering, University of Illinois at Urbana-Champaign, 1304 W Green Street, Urbana, IL 61801 (United States); Mathias, Patrick C, E-mail: bcunning@illinois.edu [Department of Bioengineering, University of Illinois at Urbana-Champaign, 1304 W Springfield Avenue, Urbana, IL 61801 (United States)

    2010-03-26

    Using a one-dimensional grating surface photonic crystal (PC), we experimentally demonstrate that the detection of fluorescent molecules on a PC surface can be substantially magnified through the combined effects of resonance-enhanced excitation of the fluorescent dye, resonance-enhanced extraction of the fluorescence emission and a dielectric nanorod surface coating increasing the surface area available for fluorophore-PC interaction. Enhanced excitation is obtained by engineering a high-Q TM resonant mode to efficiently couple with an incident TM-polarized {lambda} = 633 nm laser for exciting Cyanine-5 (Cy5). Enhanced extraction results from a low-Q TE resonance designed to spectrally overlap the Cy5 emission spectrum for channeling TE-polarized emission towards the detection instrument. The entire PC surface is coated with a porous film of TiO{sub 2} nanorods that allows more fluorophores to penetrate into the region of enhanced near-electric fields. Experimental results reveal a 588-fold enhancement in fluorescence intensity relative to an unpatterned glass surface.

  8. Complications after liver transplantation: evaluation with magnetic resonance imaging, magnetic resonance cholangiography, and 3-dimensional contrast-enhanced magnetic resonance angiography in a single session

    International Nuclear Information System (INIS)

    To evaluate a comprehensive magnetic resonance imaging (MRI) protocol as noninvasive diagnostic modality for simultaneous detection of parenchymal, biliary, and vascular complications after liver transplantation. Fifty-two liver transplant recipients suspected to have parenchymal, biliary, and (or) vascular complications underwent our MRI protocol at 1.5T unit using a phased array coil. After preliminary acquisition of axial T1w and T2w sequences, magnetic resonance cholangiography (MRC) was performed through a breath-hold, thin- and thick-slab, single-shot T2w sequence in the coronal plane. Contrast-enhanced magnetic resonance angiography (CEMRA) was obtained using a 3-dimensional coronal spoiled gradient-echo sequence, which enabled acquisition of 32 partitions 2.0 mm thick. A fixed dose of 20 ml gadobenate dimeglumine was administered at 2 mL/s. A post-contrast T1w sequence was also performed. Two observers in conference reviewed source images and 3-dimensional reconstructions to determine the presence of parenchymal, biliary, and vascular complications. MRI findings were correlated with surgery, endoscopic retrograde cholangiography (ERC), biopsy, digital subtraction angiography (DSA), and imaging follow-up. MRI revealed abnormal findings in 32 out of 52 patients (61%), including biliary complications (anastomotic and nonanastomotic strictures, and lithiasis) in 31, vascular disease (hepatic artery stenosis and thrombosis) in 9, and evidence of hepatic abscess and hematoma in 2. ERC confirmed findings of MRC in 30 cases, but suggested disease underestimation in 2. DSA confirmed 7 magnetic resonance angiogram (MRA) findings, but suggested disease overestimation in 2. MRI combined with MRC and CEMRA can provide a comprehensive assessment of parenchymal, biliary, and vascular complications in most recipients of liver transplantation. (author)

  9. Complications after liver transplantation: evaluation with magnetic resonance imaging, magnetic resonance cholangiography, and 3-dimensional contrast-enhanced magnetic resonance angiography in a single session

    Energy Technology Data Exchange (ETDEWEB)

    Boraschi, P.; Donati, F.; Gigoni, R. [Pisa Univ. Hospital, Second Dept. of Radiology, Pisa (Italy)], E-mail: p.boraschi@do.med.unipi.it; Salemi, S. [Univ. of Pisa, Diagnostic and Interventional Radiology, Pisa (Italy); Urbani, L.; Filipponi, F. [Univ. of Pisa, Liver Transplant Unit of the Dept. of Oncology, Transplants and Advanced Technologies in Medicine, Pisa (Italy); Falaschi, F. [Pisa Univ. Hospital, Second Dept. of Radiology, Pisa (Italy); Bartolozzi, C. [Univ. of Pisa, Diagnostic and Interventional Radiology, Pisa (Italy)

    2008-12-15

    To evaluate a comprehensive magnetic resonance imaging (MRI) protocol as noninvasive diagnostic modality for simultaneous detection of parenchymal, biliary, and vascular complications after liver transplantation. Fifty-two liver transplant recipients suspected to have parenchymal, biliary, and (or) vascular complications underwent our MRI protocol at 1.5T unit using a phased array coil. After preliminary acquisition of axial T{sub 1}w and T{sub 2}w sequences, magnetic resonance cholangiography (MRC) was performed through a breath-hold, thin- and thick-slab, single-shot T{sub 2}w sequence in the coronal plane. Contrast-enhanced magnetic resonance angiography (CEMRA) was obtained using a 3-dimensional coronal spoiled gradient-echo sequence, which enabled acquisition of 32 partitions 2.0 mm thick. A fixed dose of 20 ml gadobenate dimeglumine was administered at 2 mL/s. A post-contrast T{sub 1}w sequence was also performed. Two observers in conference reviewed source images and 3-dimensional reconstructions to determine the presence of parenchymal, biliary, and vascular complications. MRI findings were correlated with surgery, endoscopic retrograde cholangiography (ERC), biopsy, digital subtraction angiography (DSA), and imaging follow-up. MRI revealed abnormal findings in 32 out of 52 patients (61%), including biliary complications (anastomotic and nonanastomotic strictures, and lithiasis) in 31, vascular disease (hepatic artery stenosis and thrombosis) in 9, and evidence of hepatic abscess and hematoma in 2. ERC confirmed findings of MRC in 30 cases, but suggested disease underestimation in 2. DSA confirmed 7 magnetic resonance angiogram (MRA) findings, but suggested disease overestimation in 2. MRI combined with MRC and CEMRA can provide a comprehensive assessment of parenchymal, biliary, and vascular complications in most recipients of liver transplantation. (author)

  10. Resonant Transmission Through Two Impurities in a Narrow Quantum Wire

    Institute of Scientific and Technical Information of China (English)

    宋小龙; 赵志云; 汪源; 施耀铭

    2003-01-01

    We study electron transmission through two impurities in a narrow quantum wire by solving Dyson's equations for single electron Green functions. We have verified that, for the delta-function potential of two impurities, the Green function can be factorized into a product of the ‘free' Green function and current transmission amplitude. Meanwhile Green function and current transmission amplitude obey Fisher-Lee's relation. An analytical expression of the electron transmission amplitude for intrasubband and intersubband is obtained as a function of Fermi energy and the distance between two impurities. The resonant behavior of the current transmission amplitude are detail discussed.

  11. Resonances and Aerodynamic Damping of a Vertical Axis Wind Turbine

    OpenAIRE

    Ottermo, Fredric; Bernhoff, Hans

    2012-01-01

    The dynamics of a straight-bladed vertical axis wind turbine is investigated with respect to oscillations due to the elasticity of struts and shaft connecting to the hub. In particular, for the three-bladed turbine, a concept is proposed for dimensioning the turbine to maximize the size of the resonance free rpm range for operation. The effect of aerodynamic damping on the struts is also considered. The damping of these types of oscillations for a typical turbine is found to be good.

  12. A Quarter Ellipse Microstrip Resonator for Filters in Microwave Frequencies

    Directory of Open Access Journals (Sweden)

    Samuel Á. Jaramillo-Flórez

    2013-11-01

    Full Text Available This work describes the results of computational simulations and construction of quadrant elliptical resonators excited by coplanar slot line waveguide for designing microwave filters in RF communications systems. By means of the equation of optics, are explained the fundamentals of these geometry of resonators proposed. Are described the construction of quadrant elliptical resonators, one of microstrip and other two of cavity, of size different, and an array of four quadrant elliptical resonators in cascade. The results of the measures and the computational calculus of scattering S11 and S21 of elliptical resonators is made for to identify the resonant frequencies of the resonators studied, proving that these have performance in frequency as complete ellipses by the image effect due to their two mirror in both semiaxis, occupying less area, and the possible applications are discussed.

  13. Regenerative feedback resonant circuit

    Science.gov (United States)

    Jones, A. Mark; Kelly, James F.; McCloy, John S.; McMakin, Douglas L.

    2014-09-02

    A regenerative feedback resonant circuit for measuring a transient response in a loop is disclosed. The circuit includes an amplifier for generating a signal in the loop. The circuit further includes a resonator having a resonant cavity and a material located within the cavity. The signal sent into the resonator produces a resonant frequency. A variation of the resonant frequency due to perturbations in electromagnetic properties of the material is measured.

  14. Resonantly Enhanced Tunneling in a Double Layer Quantum Hall Ferromagnet

    Energy Technology Data Exchange (ETDEWEB)

    Spielman, I. B. [California Institute of Technology, Pasadena, California 91125 (United States); Eisenstein, J. P. [California Institute of Technology, Pasadena, California 91125 (United States); Pfeiffer, L. N. [Bell Laboratories, Lucent Technologies, Murray Hill, New Jersey 07974 (United States); West, K. W. [Bell Laboratories, Lucent Technologies, Murray Hill, New Jersey 07974 (United States)

    2000-06-19

    The tunneling conductance between two parallel 2D electron systems has been measured in a regime of strong interlayer Coulomb correlations. At total Landau level filling {nu}{sub T}=1 the tunnel spectrum changes qualitatively when the boundary separating the compressible phase from the ferromagnetic quantized Hall state is crossed. A huge resonant enhancement replaces the strongly suppressed equilibrium tunneling characteristic of weakly coupled layers. The possible relationship of this enhancement to the Goldstone mode of the broken symmetry ground state is discussed. (c) 2000 The American Physical Society.

  15. Baryon resonances without quarks: A chiral soliton perspective

    Energy Technology Data Exchange (ETDEWEB)

    Karliner, M.

    1987-03-01

    In many processes involving low momentum transfer it is fruitful to regard the nucleon as a soliton or ''monopole-like'' configuration of the pion field. In particular, within this framework it is possible to obtain detailed predictions for pion-nucleon scattering amplitudes and for properties of baryon resonances. One can also derive model-independent linear relations between scattering amplitudes, such as ..pi..N and anti KN. A short survey of some recent results is given, including comparison with experimental data.

  16. Two-band combined model of a resonant tunneling diode

    International Nuclear Information System (INIS)

    A two-band combined model of a resonant tunneling diode, based on the semiclassical and quantum mechanical (the wave function formalism) approaches is proposed. The main specific feature of this model is the possibility of taking into account the interaction between different classical or quantum mechanical device regions with simultaneous consideration of the Γ-X intervalley scattering. It is shown that this model gives satisfactory agreement with the experimental data on the current-voltage characteristics and allows explanation of the plateau region in these characteristics within the stationary model

  17. A Boost Test of Anomalous Diphoton Resonance at the LHC

    CERN Document Server

    Cao, Qing-Hong; Xie, Ke-Pan; Yan, Bin; Zhang, Dong-Ming

    2015-01-01

    The recent observed diphoton resonance around 750 GeV at the LHC Run-2 could be interpreted as a weak singlet scalar. Adapting the approach of effective field theory we argue that the scalar might also decay into $WW$ or $ZZ$ pairs, which are highly boosted and appear as two fat vector-jets in the detector. We demonstrate that the signature of two vector-jets provides a powerful tool to crosscheck the diphoton anomaly and should be explored in the LHC Run-II experiment.

  18. Predicting vibration-induced displacement for a resonant friction slider

    DEFF Research Database (Denmark)

    Fidlin, A.; Thomsen, Jon Juel

    2001-01-01

    A mathematical model is set up to quantify vibration-induced motions of a slider, sandwiched between friction layers with different coefficients of friction, and equipped with an imbedded resonator that oscillates at high frequency and small amplitude. This model is highly nonlinear, involving non......-smooth functions with strong harmonic excitation terms. The method of averaging is extended to hold for systems of this class, and used to derive approximate expressions for predicting average velocities of the slider. These expressions are shown to produce results that agree very well with numerical integration...... of the full equations of motion. The expressions are used to estimate and explain the influence of system parameters....

  19. Stellar dynamics around a massive black hole - II. Resonant relaxation

    Science.gov (United States)

    Sridhar, S.; Touma, Jihad R.

    2016-06-01

    We present a first-principles theory of resonant relaxation (RR) of a low-mass stellar system orbiting a more massive black hole (MBH). We first extend the kinetic theory of Gilbert to include the Keplerian field of a black hole of mass M•. Specializing to a Keplerian stellar system of mass M ≪ M•, we use the orbit-averaging method of Sridhar & Touma to derive a kinetic equation for RR. This describes the collisional evolution of a system of N ≫ 1 Gaussian rings in a reduced 5-dim space, under the combined actions of self-gravity, 1 post-Newtonian (PN) and 1.5 PN relativistic effects of the MBH and an arbitrary external potential. In general geometries, RR is driven by both apsidal and nodal resonances, so the distinction between scalar RR and vector RR disappears. The system passes through a sequence of quasi-steady secular collisionless equilibria, driven by irreversible two-ring correlations that accrue through gravitational interactions, both direct and collective. This correlation function is related to a `wake function', which is the linear response of the system to the perturbation of a chosen ring. The wake function is easier to appreciate, and satisfies a simpler equation, than the correlation function. We discuss general implications for the interplay of secular dynamics and non-equilibrium statistical mechanics in the evolution of Keplerian stellar systems towards secular thermodynamic equilibria, and set the stage for applications to the RR of axisymmetric discs in Paper III.

  20. Fano resonance control in a photonic crystal structure and its application to ultrafast switching

    CERN Document Server

    Yu, Yi; Hu, Hao; Xue, Weiqi; Peucheret, Christophe; Chen, Yaohui; Oxenløwe, Leif Katsuo; Yvind, Kresten; Mørk, Jesper

    2014-01-01

    Fano resonances appear in quantum mechanical as well as classical systems as a result of the interference between two paths: one involving a discrete resonance and the other a continuum. Compared to a conventional resonance, characterized by a Lorentzian spectral response, the characteristic asymmetric and sharp spectral response of a Fano resonance is suggested to enable photonic switches and sensors with superior characteristics. While experimental demonstrations of the appearance of Fano resonances have been made in both plasmonic and photonic-crystal structures, the control of these resonances is experimentally challenging, often involving the coupling of near-resonant cavities. Here, we experimentally demonstrate two simple structures that allow surprisingly robust control of the Fano spectrum. One structure relies on controlling the amplitude of one of the paths and the other uses symmetry breaking. Short-pulse dynamic measurements show that besides drastically increasing the switching contrast, the tra...

  1. Non-blinking quantum dot with a plasmonic nanoshell resonator.

    Science.gov (United States)

    Ji, Botao; Giovanelli, Emerson; Habert, Benjamin; Spinicelli, Piernicola; Nasilowski, Michel; Xu, Xiangzhen; Lequeux, Nicolas; Hugonin, Jean-Paul; Marquier, Francois; Greffet, Jean-Jacques; Dubertret, Benoit

    2015-02-01

    Colloidal semiconductor quantum dots are fluorescent nanocrystals exhibiting exceptional optical properties, but their emission intensity strongly depends on their charging state and local environment. This leads to blinking at the single-particle level or even complete fluorescence quenching, and limits the applications of quantum dots as fluorescent particles. Here, we show that a single quantum dot encapsulated in a silica shell coated with a continuous gold nanoshell provides a system with a stable and Poissonian emission at room temperature that is preserved regardless of drastic changes in the local environment. This novel hybrid quantum dot/silica/gold structure behaves as a plasmonic resonator with a strong Purcell factor, in very good agreement with simulations. The gold nanoshell also acts as a shield that protects the quantum dot fluorescence and enhances its resistance to high-power photoexcitation or high-energy electron beams. This plasmonic fluorescent resonator opens the way to a new family of plasmonic nanoemitters with robust optical properties. PMID:25581887

  2. Quantum Light from a Whispering-Gallery-Mode Disk Resonator

    DEFF Research Database (Denmark)

    Fürst, J. U.; Strekalov, D. V.; Elser, D.;

    2011-01-01

    Optical parametric down-conversion has proven to be a valuable source of nonclassical light. The process is inherently able to produce twin-beam correlations along with individual intensity squeezing of either parametric beam, when pumped far above threshold. Here, we present for the first time...... strong optical confinement and offer tunable coupling to an external optical field. This work exemplifies the potential of crystalline whispering-gallery-mode resonators for the generation of quantum light. The simplicity of this device makes the application of quantum light in various fields highly...

  3. Resonant Landau–Zener transitions in a helical magnetic field

    International Nuclear Information System (INIS)

    Spin-dependent electron transport has been studied in magnetic semiconductor waveguides (nanowires) in the helical magnetic field. We have shown that—apart from the well-known conductance dip located at the magnetic field equal to the helical-field amplitude Bh—the additional conductance dips (with zero conductance) appear at a magnetic field different from Bh. This effect occurring in the non-adiabatic regime is explained as resulting from the resonant Landau–Zener transitions between the spin-split subbands. (paper)

  4. A Small Signal Equivalent Circuit Model for Resonant Tunnelling Diode

    Institute of Scientific and Technical Information of China (English)

    MA Long; HUANG Ying-Long; ZHANG Yang; WANG Liang-Chen; YANG Fu-Hua; ZENG Yi-Ping

    2006-01-01

    @@ We report a resonant tunnelling diode (RTD) small signal equiwlent circuit model consisting of quantum capacitance and quantum inductance. The model is verified through the actual InAs/In0.53Ga0.47As/AlAs RTD fabricated on an InP substrate. Model parameters are extracted by fitting the equivalent circuit model with ac measurement data in three different regions of RTD current-voltage (Ⅰ-Ⅴ) characteristics. The electron lifetime,representing the average time that the carriers remain in the quasibound states during the tunnelling process, is also calculated to be 2.09ps.

  5. Magnetic resonance imaging for the ophthalmologist: A primer

    Directory of Open Access Journals (Sweden)

    Arathi Simha

    2012-01-01

    Full Text Available Magnetic resonance imaging (MRI and computerized tomography (CT have added a new dimension in the diagnosis and management of ocular and orbital diseases. Although CT is more widely used, MRI is the modality of choice in select conditions and can be complimentary to CT in certain situations. The diagnostic yield is best when the ophthalmologist and radiologist work together. Ophthalmologists should be able to interpret these complex imaging modalities as better clinical correlation is then possible. In this article, we attempt to describe the basic principles of MRI and its interpretation, avoiding confusing technical terms.

  6. Is there a giant monopole resonance in 12C

    International Nuclear Information System (INIS)

    Arguments that the 0+ (Esub(x)=20.3 MeV) state recently found in 12C can be interpreted as a giant resonance are given. The calculations of differential cross sections of the 0+ state excitation in elastic and inelastic scattering of 3He, 4He and 6Li on 12C and compared with experimental data. Using transition densities calculated in the hyperspherical function method it is shown that in the framework of the collective model this single state exhausts the monopole energy weighted sum rules

  7. Active plasma resonance spectroscopy: A functional analytic description

    CERN Document Server

    Lapke, Martin; Mussenbrock, Thomas; Brinkmann, Ralf Peter

    2012-01-01

    The term "Active Plasma Resonance Spectroscopy" refers to a class of diagnostic methods which employ the ability of plasmas to resonate on or near the plasma frequency. The basic idea dates back to the early days of discharge physics: An signal in the GHz range is coupled to the plasma via an electrical probe; the spectral response is recorded, and then evaluated with a mathematical model to obtain information on the electron density and other plasma parameters. In recent years, the concept has found renewed interest as a basis of industry compatible plasma diagnostics. This paper analyzes the diagnostics technique in terms of a general description based on functional analytic (or Hilbert Space) methods which hold for arbitrary probe geometries. It is shown that the response function of the plasma-probe system can be expressed as a matrix element of the resolvent of an appropriately defined dynamical operator. A specialization of the formalism for a symmetric probe desing is given, as well as an interpreation...

  8. Nonlinear resonances and antiresonances of a forced sonic vacuum

    Science.gov (United States)

    Pozharskiy, D.; Zhang, Y.; Williams, M. O.; McFarland, D. M.; Kevrekidis, P. G.; Vakakis, A. F.; Kevrekidis, I. G.

    2015-12-01

    We consider a harmonically driven acoustic medium in the form of a (finite length) highly nonlinear granular crystal with an amplitude- and frequency-dependent boundary drive. Despite the absence of a linear spectrum in the system, we identify resonant periodic propagation whereby the crystal responds at integer multiples of the drive period and observe that this can lead to local maxima of transmitted force at its fixed boundary. In addition, we identify and discuss minima of the transmitted force ("antiresonances") between these resonances. Representative one-parameter complex bifurcation diagrams involve period doublings and Neimark-Sacker bifurcations as well as multiple isolas (e.g., of period-3, -4, or -5 solutions entrained by the forcing). We combine them in a more detailed, two-parameter bifurcation diagram describing the stability of such responses to both frequency and amplitude variations of the drive. This picture supports a notion of a (purely) "nonlinear spectrum" in a system which allows no sound wave propagation (due to zero sound speed: the so-called sonic vacuum). We rationalize this behavior in terms of purely nonlinear building blocks: apparent traveling and standing nonlinear waves.

  9. Optomechanical THz detection with a sub-wavelength resonator

    CERN Document Server

    Belacel, Cherif; Barbieri, Stefano; Gacemi, Djamal; Favero, Ivan; Sirtori, Carlo

    2016-01-01

    The terahertz spectral domain offers a myriad of applications spanning chemical spectroscopy, medicine, security and imaging [1], it has also recently become a playground for fundamental studies of light-matter interactions [2-6]. Terahertz science and technology could benefit from optomechanical approaches, which harness the interaction of light with miniature mechanical resonators [7,8]. So far, optomechanics has mostly focused on the optical and microwave domains, leading to new types of quantum experiments [9-11] and to the development of optical-microwave converters [12-14]. Here we propose and validate the concept of terahertz optomechanics, by coupling far-infrared photons to the mechanical degrees of freedom of the flexible part of a sub-wavelength split-ring resonator [15]. The resulting mechanical signal is read-out optically, allowing our semiconductor/metal device to operate as a compact and efficient terahertz detector with a noise equivalent power of 8 nW/Hz^0.5 and a linear dynamics over five d...

  10. Liquid-body resonance while contacting a rotating superhydrophobic surface.

    Science.gov (United States)

    Chong, Matthew Lai Ho; Cheng, Michael; Katariya, Mayur; Muradoglu, Murat; Cheong, Brandon Huey-Ping; Zahidi, Alifa Afiah Ahmad; Yu, Yang; Liew, Oi Wah; Ng, Tuck Wah

    2015-11-01

    We advance a scheme in which a liquid body on a stationary tip in contact with a rotating superhydrophobic surface is able to maintain resonance primarily from stick-slip events. With tip-to-surface spacing in the range 2.73 ≤ h body was found to exhibit resonance independent of the speed of the drum. The mechanics were found to be due to a surface-tension-controlled vibration mode based on the natural frequency values determined. With spacing in the range 2.45 ≤ h body was found to vary with rotation of the SH drum. This was due to the stick-slip events being able to generate higher energy fluctuations causing the liquid-solid contact areas to vary since the almost oblate spheroid shape of the liquid body had intrinsically higher surface energies. This resulted in the natural frequency perturbations being frequency- and amplitude-modulated over a lower frequency carrier. These findings have positive implications for microfluidic sensing. PMID:26577818

  11. Detection of Carcinoembryonic Antigens Using a Surface Plasmon Resonance Biosensor

    Directory of Open Access Journals (Sweden)

    Shin-Ichiro Nishimura

    2008-07-01

    Full Text Available Carcinoembryonic antigen (CEA is an oncofoetal cell-surface glycoprotein that serves as an important tumor marker for colorectal and some other carcinomas. In this work, a CEA immunoassay using a surface plasmon resonance (SPR biosensor has been developed. SPR could provide label-free, real-time detection with high sensitivity, though its ability to detect CEA in human serum was highly dependent on the analytical conditions employed. We investigated the influences of various analytical conditions including immobilization methods for anti-CEA antibody and composition of sensor surface on the selective and sensitive detection of CEA. The results show that anti-CEA antibody immobilized via Protein A or Protein G caused a large increase in the resonance signal upon injection of human serum due to the interactions with IgGs in serum, while direct covalent immobilization of anti-CEA antibody could substantially reduce it. An optimized protocol based on further kinetic analysis and the use of 2nd and 3rd antibodies for the sandwich assay allowed detecting spiked CEA in human serum as low as 25 ng/mL. Furthermore, a self-assembled monolayer of mixed ethylene-glycol terminated alkanethiols on gold was found to have a comparable ability in detecting CEA as CM5 with thick dextran matrix and C1 with short flat layer on gold.

  12. External laser locking using a pressure-tunable microbubble resonator

    CERN Document Server

    Madugani, Ramgopal; Le, Vu H; Ward, Jonathan M; Chormaic, Síle Nic

    2015-01-01

    The tunability of an optical cavity is an essential requirement for many areas of research especially for the rapidly progressing field of photonics. In particular, low-cost laser tuning methods and miniaturization of the optical components are desirable. By applying aerostatic pressure to the interior surface of a microbubble resonator, optical mode shift rates of around $58$ GHz/MPa are achieved. The micobubble can measure pressure with a limit of detection of $2\\times 10^{-4}$ MPa. Here we use the Pound-Drever-Hall technique, whereby a laser is locked to a whispering gallery mode (WGM) of the microbubble resonator, to show that linear tuning of the WGM and the corresponding locked laser display almost zero hysteresis. The long-term frequency stability of this tuning method for different input pressures is measured. The frequency noise of the WGM, measured over 10 minutes, with a maximum input pressure of 0.5 MPa has a standard deviation of 36 MHz.

  13. Electrical conductivity of Jupiter's shallow interior and the formation of a resonant of a resonant planetary-ionospheric cavity

    Science.gov (United States)

    Sentman, D. D.

    1990-01-01

    The present consideration of hydrogenic atmospheric reactions on Jupiter, to a depth of 4000 km, notes the primary ion constituents at these depths to be both positive and negative ions of molecular hydrogen contributing less than 20 percent to total electrical conductivity by free electrons. An electrical surface defined by the boundary beneath which the interior is electrically conducting exists at depths which vary according to EM wave frequency, from 1100 km for 1 mHz to 3000 for 1 MHz. The presence of a lower electrical boundary within the shallow interior suggests that a planetary-ionosphere resonant cavity analogous to the earth-ionosphere cavity may exist.

  14. Electrical conductivity of Jupiter's shallow interior and the formation of a resonant of a resonant planetary-ionospheric cavity

    International Nuclear Information System (INIS)

    The present consideration of hydrogenic atmospheric reactions on Jupiter, to a depth of 4000 km, notes the primary ion constituents at these depths to be both positive and negative ions of molecular hydrogen contributing less than 20 percent to total electrical conductivity by free electrons. An electrical surface defined by the boundary beneath which the interior is electrically conducting exists at depths which vary according to EM wave frequency, from 1100 km for 1 mHz to 3000 for 1 MHz. The presence of a lower electrical boundary within the shallow interior suggests that a planetary-ionosphere resonant cavity analogous to the earth-ionosphere cavity may exist. 36 refs

  15. Observation of a surface lattice resonance in a fractal arrangement of gold nanoparticles

    CERN Document Server

    Chen, Ting Lee; Segerink, Frans B; Dikken, Dirk Jan; Herek, Jennifer L

    2015-01-01

    The collective response of closely spaced metal particles in non-periodic arrangements has the potential to provide a beneficial angular and frequency dependence in sensing applications. In this paper, we investigate the optical response of a Sierpinski fractal arrangement of gold nanoparticles and show that it supports a collective resonance similar to the surface lattice resonances that exist in periodic arrangements of plasmonic resonators. Using back focal plane microscopy, we observe the leakage of radiation out of a surface lattice resonance that is efficiently excited when the wavenumber of the incident light matches a strong Fourier component of the fractal structure. The efficient coupling between localized surface plasmons leads to a collective resonance and a Fano-like feature in the scattering spectrum. Our experimental observations are supported by numerical simulations based on the coupled-dipole approximation and finite-difference time-domain methods. This work presents a first step towards the...

  16. A piezoelectric cantilever with a Helmholtz resonator as a sound pressure sensor

    International Nuclear Information System (INIS)

    In this paper, a piezoelectric cantilever with a Helmholtz resonator (HR) is proposed as a sound pressure sensor that generates a sufficiently large output voltage at a specific frequency without a power supply to drive the sensing element. A Pb (Zr, Ti) O3 (PZT) cantilever with dimensions of 1500 µm × 1000 µm × 2 µm is designed so that its mechanical resonance frequency agrees with the target frequency. When sound pressure is applied at the target frequency, a large piezoelectric voltage can be obtained due to a high amplification ratio. Additionally, the PZT cantilever is combined with a HR whose resonant frequency is designed to be equal to that of the cantilever. This multiplication of two resonant vibration systems can generate detectable signals by sound pressures of several Pascals. The fabricated sensor generated a piezoelectric voltage of 13.4 mV Pa−1 at the resonant frequency of 2.6 kHz. Furthermore, the fabricated sensor performed as an electrical trigger switch when a sound pressure of 2 Pa was applied at the resonant frequency. (paper)

  17. A Controllability Approach for Resonant Compliant Systems: Applied to a Flapping Wing Micro Air Vehicle

    NARCIS (Netherlands)

    Peters, H.J.

    2016-01-01

    This thesis studies a controllability approach for general resonant compliant systems. These systems exploit resonance to obtain a specific dynamic response at relatively low actuation power. This type of systems is often lightweight, is scalable and minimizes frictional losses through the use of co

  18. Changing the colour of light in a silicon resonator

    Science.gov (United States)

    Preble, Stefan F.; Xu, Qianfan; Lipson, Michal

    2007-05-01

    As the demand for high bandwidths in microelectronic systems increases, optical interconnect architectures are now being considered that involve schemes commonly used in telecommunications, such as wavelength-division multiplexing (WDM) and wavelength conversion. In such on-chip architectures, the ability to perform wavelength conversion is required. So far wavelength conversion on a silicon chip has only been demonstrated using schemes that are fundamentally all-optical, making their integration on a microelectronic chip challenging. In contrast, we show wavelength conversion obtained by inducing ultrafast electro-optic tuning of a microcavity. It is well known that tuning the parameters of an optical cavity induces filtering of different colours of light. Here we demonstrate that it can also change the colour of light. This is an effect often observed in other disciplines, for example, in acoustics, where the sound generated by a resonating guitar string can be modified by changing the length of the strings (that is, the resonators). Here we show this same tuning effect in optics, enabling compact on-chip electrical wavelength conversion. We demonstrate a change in wavelength of up to 2.5 nm with up to 34% on-off conversion efficiency.

  19. A Map for a Group of Resonant Cases in a Quartic Galactic Hamiltonian

    Indian Academy of Sciences (India)

    N. D. Caranicolas

    2001-12-01

    We present a map for the study of resonant motion in a potential made up of two harmonic oscillators with quartic perturbing terms. This potential can be considered to describe motion in the central parts of non-rotating elliptical galaxies. The map is based on the averaged Hamiltonian. Adding on a semi-empirical basis suitable terms in the unperturbed averaged Hamiltonian, corresponding to the 1:1 resonant case, we are able to construct a map describing motion in several resonant cases. The map is used in order to find the - Poincare phase plane for each resonance. Comparing the results of the map, with those obtained by numerical integration of the equation of motion, we observe, that the map describes satisfactorily the broad features of orbits in all studied cases for regular motion. There are cases where the map describes satisfactorily the properties of the chaotic orbits as well.

  20. A Refined Analysis on the $X(3872)$ Resonance

    CERN Document Server

    Meng, Ce; Shi, Meng; Yao, De-Liang; Zheng, Han-Qing

    2014-01-01

    We study the property of the $X(3872)$ meson by analyzing the $B\\to K D\\bar D^*$ and $B\\to K J/\\psi \\pi^+\\pi^-$ decay processes. The competition between the rescattering mediated through a Breit-Wigner resonance and the rescattering generated from a local $D\\bar{D}^* \\to D\\bar{D}^*$ interaction is carefully studied through an effective lagrangian approach. Three different fits are performed: pure Breit-Wigner case, pure $D\\bar{D}^*$ molecule case with only local rescattering vertices (generated by the loop chain), and the mixed case. It is found that data supports the picture where X(3872) is mainly a ($\\bar cc$) Breit-Wigner resonance with a small contribution to the self-energy generated by $\\bar DD^*$ final state interaction. For our optimal fit, the pole mass and width are found to be: $M_X=3871.2\\pm0.7$MeV and $\\Gamma_X=6.5\\pm1.2$MeV.

  1. The preparation of a plasmonically resonant VO2 thermochromic pigment

    Science.gov (United States)

    Bai, Huaping; Cortie, Michael B.; Maaroof, Abbas I.; Dowd, Annette; Kealley, Catherine; Smith, Geoffrey B.

    2009-02-01

    Vanadium dioxide (VO2) undergoes a reversible metal-insulator transition, normally at ~68 °C. While the properties of continuous semi-transparent coatings of VO2 are well known, there is far less information available concerning the potential use of discrete VO2 nanoparticles as a thermochromic pigment in opaque coatings. Individual VO2 nanoparticles undergo a localized plasmon resonance with near-infrared light at about 1100 nm and this resonance can be switched on and off by simply varying the temperature of the system. Therefore, incorporation of VO2 nanoparticles into a coating system imbues the coating with the ability to self-adaptively modulate its own absorptive efficiency in the near-infrared. Here we examine the magnitude and control of this phenomenon. Prototype coatings are described, made using VO2 powder produced by an improved process. The materials are characterized using calorimetry, x-ray diffraction, high-resolution scanning electron microscopy, transmission electron microscopy, and by measurement of optical properties.

  2. Bioceramic Resonance Effect on Meridian Channels: A Pilot Study

    Directory of Open Access Journals (Sweden)

    Ting-Kai Leung

    2015-01-01

    Full Text Available Bioceramic is a kind of material which emits nonionizing radiation and luminescence, induced by visible light. Bioceramic also facilitates the breakup of large clusters of water molecules by weakening hydrogen bonds. Hydrogen bond weakening, which allows water molecules to act in diverse ways under different conditions, is one of the key mechanisms underlying the effects of Bioceramic on biophysical and physical-chemical processes. Herein, we used sound to amplify the effect of Bioceramic and further developed an experimental device for use in humans. Thirteen patients who suffered from various chronic and acute illnesses that severely affected their sleep patterns and life quality were enrolled in a trial of Bioceramic resonance (i.e., rhythmic 100-dB sound waves with frequency set at 10 Hz applied to the skin surface of the anterior chest. According to preliminary data, a “Propagated Sensation along Meridians” (PSM was experienced in all Bioceramic resonance-treated patients but not in any of the nine control patients. The device was believed to enhance microcirculation through a series of biomolecular and physiological processes and to subject the specific meridian channels of Traditional Chinese Medicine (TCM to coherent vibration. This noninvasive technique may offer an alternative to needle acupuncture and other traditional medical practices with clinical benefits.

  3. Jet activity as a probe of diphoton resonance production

    CERN Document Server

    Harland-Lang, L A; Ryskin, M G; Spannowsky, M

    2016-01-01

    We explore the method of using the measured jet activity associated with a high mass resonance state to determine the corresponding production modes. To demonstrate the potential of the approach, we concentrate on the scenario that the excess of diphoton events around 750 GeV observed by the ATLAS and CMS collaborations corresponds to a new scalar resonance. We perform a Monte Carlo study, and show that the $\\gamma\\gamma$, $gg$ and light and heavy $q\\overline{q}$ initiated cases lead to distinct predictions for the jet multiplicity distributions. We apply this result to the existing ATLAS data for the spin-0 selection, and demonstrate that a dominantly $gg$-initiated signal hypothesis is already mildly disfavoured, while the $\\gamma\\gamma$ and light quark cases give good descriptions within the limited statistics. We also comment on the $b\\overline{b}$ initial state, which can already be constrained by the measured $b$-jet multiplicity, and the $W$, $Z$ initial states, for which the diphoton transverse moment...

  4. Nonlinear resonances

    CERN Document Server

    Rajasekar, Shanmuganathan

    2016-01-01

    This introductory text presents the basic aspects and most important features of various types of resonances and anti-resonances in dynamical systems. In particular, for each resonance, it covers the theoretical concepts, illustrates them with case studies, and reviews the available information on mechanisms, characterization, numerical simulations, experimental realizations, possible quantum analogues, applications and significant advances made over the years. Resonances are one of the most fundamental phenomena exhibited by nonlinear systems and refer to specific realizations of maximum response of a system due to the ability of that system to store and transfer energy received from an external forcing source. Resonances are of particular importance in physical, engineering and biological systems - they can prove to be advantageous in many applications, while leading to instability and even disasters in others. The book is self-contained, providing the details of mathematical derivations and techniques invo...

  5. MRI (Magnetic Resonance Imaging)

    Science.gov (United States)

    ... Procedures Medical Imaging MRI (Magnetic Resonance Imaging) MRI (Magnetic Resonance Imaging) Share Tweet Linkedin Pin it More sharing options ... 8 MB) Also available in Other Language versions . Magnetic Resonance Imaging (MRI) is a medical imaging procedure for making ...

  6. Mie scattering as a cascade of Fano resonances.

    Science.gov (United States)

    Rybin, Mikhail V; Samusev, Kirill B; Sinev, Ivan S; Semouchkin, George; Semouchkina, Elena; Kivshar, Yuri S; Limonov, Mikhail F

    2013-12-01

    We reveal that the resonant Mie scattering by high-index dielectric nanoparticles can be presented through cascades of Fano resonances. We employ the exact solution of Maxwell's equations and demonstrate that the Lorenz-Mie coefficients of the Mie problem can be expressed generically as infinite series of Fano functions as they describe interference between the background radiation originated from an incident wave and narrow-spectrum Mie scattering modes that lead to Fano resonances. PMID:24514559

  7. A personal computer-based nuclear magnetic resonance spectrometer

    Science.gov (United States)

    Job, Constantin; Pearson, Robert M.; Brown, Michael F.

    1994-11-01

    Nuclear magnetic resonance (NMR) spectroscopy using personal computer-based hardware has the potential of enabling the application of NMR methods to fields where conventional state of the art equipment is either impractical or too costly. With such a strategy for data acquisition and processing, disciplines including civil engineering, agriculture, geology, archaeology, and others have the possibility of utilizing magnetic resonance techniques within the laboratory or conducting applications directly in the field. Another aspect is the possibility of utilizing existing NMR magnets which may be in good condition but unused because of outdated or nonrepairable electronics. Moreover, NMR applications based on personal computer technology may open up teaching possibilities at the college or even secondary school level. The goal of developing such a personal computer (PC)-based NMR standard is facilitated by existing technologies including logic cell arrays, direct digital frequency synthesis, use of PC-based electrical engineering software tools to fabricate electronic circuits, and the use of permanent magnets based on neodymium-iron-boron alloy. Utilizing such an approach, we have been able to place essentially an entire NMR spectrometer console on two printed circuit boards, with the exception of the receiver and radio frequency power amplifier. Future upgrades to include the deuterium lock and the decoupler unit are readily envisioned. The continued development of such PC-based NMR spectrometers is expected to benefit from the fast growing, practical, and low cost personal computer market.

  8. Performance optimization analysis of a thermoelectric refrigerator with two resonances

    Institute of Scientific and Technical Information of China (English)

    Luo Xiao-Guang; He Ji-Zhou

    2011-01-01

    Based on electron transport theory, the performance of kx and kr filtered thermoelectric refrigerators with two resonances are studied in this paper. The performance characteristic curves between the cooling rate and the coefficient of performance are plotted by numerical calculation. It is shown that the maximum cooling rate of the thermoelectric refrigerator with two resonances increases but the maximum coefficient of performance decreases compared with those with one resonance. No matter which resonance mechanism is used (kx or kr filtered), the cooling rate and the performance coefficient of the kr filtered refrigerator are much better than those of the kx filtered one.

  9. Single-Photon Transistor Using a Förster Resonance

    Science.gov (United States)

    Tiarks, Daniel; Baur, Simon; Schneider, Katharina; Duerr, Stephan; Rempe, Gerhard

    2015-05-01

    An all-optical transistor is a device in which a gate light pulse switches the transmission of a target light pulse with a gain above unity. The gain quantifies the change of the transmitted target photon number per incoming gate photon. We study the quantum limit of one incoming gate photon and observe a gain of 20. The gate pulse is stored as a Rydberg excitation in an ultracold gas. The transmission of the subsequent target pulse is suppressed by Rydberg blockade which is enhanced by a Förster resonance. The detected target photons reveal in a single shot with a fidelity above 0.86 whether a Rydberg excitation was created during the gate pulse. The gain offers the possibility to distribute the transistor output to the inputs of many transistors, thus making complex computational tasks possible.

  10. Ovenized microelectromechanical system (MEMS) resonator

    Science.gov (United States)

    Olsson, Roy H; Wojciechowski, Kenneth; Kim, Bongsang

    2014-03-11

    An ovenized micro-electro-mechanical system (MEMS) resonator including: a substantially thermally isolated mechanical resonator cavity; a mechanical oscillator coupled to the mechanical resonator cavity; and a heating element formed on the mechanical resonator cavity.

  11. Acoustic self-induced transparency for transverse waves in a system with resonant and quasi-resonant transitions

    Science.gov (United States)

    Sazonov, S. V.

    2009-07-01

    A theoretical analysis of acoustic self-induced transparency is presented for transverse elastic waves propagating perpendicular to an applied magnetic field through a crystal with spin-3/2 paramagnetic impurities. The interaction between an acoustic pulse and magnetic field is described by Maxwell-Bloch-type equations for a system with transitions inhomogeneously broadened because of a quadrupole Stark shift. If the pulse carrier frequency is resonant with one transition and quasi-resonant with another transition, then the evolution of a one-dimensional pulse is described by an integrable Konno-Kameyama-Sanuki (KKS) equation. The underlying physics of its soliton solution and the corresponding behavior of the medium are analyzed. Self-focusing and self-trapping conditions are found for a pulse of finite transverse size. In the latter regime, the pulse stretches along the propagation direction, transforming into a “hollow bullet,” while its transverse size remains constant.

  12. Power meter ratio method of stabilizing a resonant modulator

    Energy Technology Data Exchange (ETDEWEB)

    Lentine, Anthony L.; Cox, Jonathan Albert

    2016-10-11

    Methods and systems for stabilizing a resonant modulator include receiving pre-modulation and post-modulation portions of a carrier signal, determining the average power from these portions, comparing an average input power to the average output power, and operating a heater coupled to the modulator based on the comparison. One system includes a pair of input structures, one or more processing elements, a comparator, and a control element. The input structures are configured to extract pre-modulation and post-modulation portions of a carrier signal. The processing elements are configured to determine average powers from the extracted portions. The comparator is configured to compare the average input power and the average output power. The control element operates a heater coupled to the modulator based on the comparison.

  13. Rapid Driven Reset of a Qubit Readout Resonator

    Science.gov (United States)

    McClure, D. T.; Paik, Hanhee; Bishop, L. S.; Steffen, M.; Chow, Jerry M.; Gambetta, Jay M.

    2016-01-01

    Using a circuit QED device, we demonstrate a simple qubit-measurement pulse shape that yields fast ring-up and ring-down of the readout resonator regardless of the qubit state. The pulse differs from a square pulse only by the inclusion of additional constant-amplitude segments designed to effect a rapid transition from one steady-state population to another. Using a Ramsey experiment performed shortly after the measurement pulse to quantify the residual population, we find that compared to a square pulse followed by a delay, this pulse shape reduces the time scale for cavity ring-down by more than twice the cavity time constant. At low drive powers, this performance is achieved using pulse parameters calculated from a linear cavity model; at higher powers, empirical optimization of the pulse parameters leads to similar performance.

  14. Magnetic resonance angiography

    Science.gov (United States)

    MRA; Angiography - magnetic resonance ... Kwong RY. Cardiovascular Magnetic Resonance Imaging. In: Bonow RO, Mann DL, Zipes DP, Libby P, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine . ...

  15. Coupled channel study of a sub 0 resonances

    CERN Document Server

    Furman, A

    2002-01-01

    A coupled channel model of the a sub 0 (980) and a sub 0 (1450) resonances has been constructed using the separable pi eta and K(anti)K interactions. We have shown that two S-matrix poles corresponding to the a sub 0 (980) meson have significantly different widths in the complex energy plane. The K(anti)K to pi eta branching ratio, predicted in our model near the a sub 0 (1450) mass, is in agreement with the result of the Crystal Barrel Collaboration, The K(anti)K interaction in the S-wave isovector state is not sufficiently attractive to create a bound a sub 0 (980) meson.

  16. Hybrid polaritons in a resonant inorganic/organic semiconductor microcavity

    Energy Technology Data Exchange (ETDEWEB)

    Höfner, M., E-mail: mhoefner@physik.hu-berlin.de; Sadofev, S.; Henneberger, F. [Institut für Physik, Humboldt-Universität zu Berlin, Newtonstr.15, 12489 Berlin (Germany); Kobin, B.; Hecht, S. [Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin (Germany)

    2015-11-02

    We demonstrated the strong coupling regime in a hybrid inorganic-organic microcavity consisting of (Zn,Mg)O quantum wells and ladder-type oligo(p-phenylene) molecules embedded in a polymer matrix. A Fabry-Pérot cavity is formed by an epitaxially grown lower ZnMgO Bragg reflector and a dielectric mirror deposited atop of the organic layer. A clear anticrossing behavior of the polariton branches related to the Wannier-Mott and Frenkel excitons, and the cavity photon mode with a Rabi-splitting reaching 50 meV, is clearly identified by angular-dependent reflectivity measurements at low temperature. By tailoring the structural design, an equal mixing with weights of about 0.3 for all three resonances is achieved for the middle polariton branch at an incidence angle of about 35°.

  17. Photonic measurement of microwave frequency using a silicon microdisk resonator

    Science.gov (United States)

    Liu, Li; Jiang, Fan; Yan, Siqi; Min, Shucun; He, Mengying; Gao, Dingshan; Dong, Jianji

    2015-01-01

    A simple photonic approach to the measurement of microwave signal frequency with adjustable measurement range and resolution is proposed and demonstrated. In this approach, the unknown microwave signal is converted to an optical signal with single sideband modulation. Subsequently, a notch microwave photonic filter (MPF) is implemented by employing a high-Q silicon microdisk resonator (MDR). The MPF is tunable by changing the frequency interval between the optical carrier and the MDR notch so as to obtain different amplitude responses. A fixed frequency-to-power mapping is established by obtaining an amplitude comparison function (ACF) of the microwave power ratio and the microwave frequency. A proof-of-concept experiment demonstrates a frequency measurement range of 10 GHz, with measurement error of ±0.1 GHz. Different frequency measurement ranges and resolutions are also discussed.

  18. $\\Delta^{++}$ resonance measurements in a high multiplicity environment

    CERN Document Server

    El Chenawi, Karim

    1999-01-01

    The very large multiplicity of charged particles encountered in lead on lead collisions in the WA98 experiment at the CERN SPS provided new experimental challenges. Tracking detectors read out with high granularity were developed to achieve accurate position information in two dimensions, with the aim of reconstructing tracks with a minimum of combinatorial difficulties. A tracking system based on multi-step avalanche chambers equipped with a new electronic readout system was developed and implemented in the experiment during 1996. The different aspects of the tracking system and its performance are described. The extraction of the $\\Delta\\sp{++}$ resonance from high statistics, high multiplicity samples of FRITIOF events has been studied in order to find a reliable method to reconstruct the number of produced $\\Delta\\sp{++}$. The first measurement on $\\Delta\\sp{++}$ production in 158 A GeV Pb$+$Pb collisions, using the high resolution tracking system in WA98 is presented.

  19. Coupled mode parametric resonance in a vibrating screen model

    CERN Document Server

    Slepyan, Leonid I

    2013-01-01

    We consider a simple dynamic model of the vibrating screen operating in the parametric resonance (PR) mode. This model was used in the course of designing and setting of such a screen in LPMC. The PR-based screen compares favorably with conventional types of such machines, where the transverse oscillations are excited directly. It is characterized by larger values of the amplitude and by insensitivity to damping in a rather wide range. The model represents an initially strained system of two equal masses connected by a linearly elastic string. Self-equilibrated, longitudinal, harmonic forces act on the masses. Under certain conditions this results in transverse, finite-amplitude oscillations of the string. The problem is reduced to a system of two ordinary differential equations coupled by the geometric nonlinearity. Damping in both the transverse and longitudinal oscillations is taken into account. Free and forced oscillations of this mass-string system are examined analytically and numerically. The energy e...

  20. Resonant tunneling diode with a multiplication region for light detection

    Science.gov (United States)

    Dong, Yu; Wang, Guanglong; Ni, Haiqiao; Chen, Jianhui; Gao, Fengqi; Qiao, Zhongtao; Niu, Zhichuan

    2014-11-01

    A resonant tunneling diode (RTD) with a multiplication region is designed for light detection in this paper. Via adding a n+-i-p+ multiplication region, we focus on promoting the photocurrent and light sensitivity of the detector. Through the calculation of the multiplication factor, the thickness of the multiplication region is determined. The influence factors of the electric field and potential distribution of the detector are investigated, thereby the thickness and doping concentration of the doped layers besides the double-barrier structure (DBS) are decided. Detectors with and without a multiplication region are fabricated from semiconductor heterostructures grown by molecular beam epitaxy. The current-voltage (I-V) and light sensitivity tests show that the detector with a multiplication region has better performance in peak photocurrent and light sensitivity.

  1. Microtesla magnetic resonance imaging with a superconducting quantum interference device

    Energy Technology Data Exchange (ETDEWEB)

    McDermott, Robert; Lee, SeungKyun; ten Haken, Bennie; Trabesinger, Andreas H.; Pines, Alexander; Clarke, John

    2004-03-15

    We have constructed a magnetic resonance imaging (MRI) scanner based on a dc Superconducting QUantum Interference Device (SQUID) configured as a second-derivative gradiometer. The magnetic field sensitivity of the detector is independent of frequency; it is therefore possible to obtain high-resolution images by prepolarizing the nuclear spins in a field of 300 mT and detecting the signal at 132 fYT, corresponding to a proton Larmor frequency of 5.6 kHz. The reduction in the measurement field by a factor of 10,000 compared with conventional scanners eliminates inhomogeneous broadening of the nuclear magnetic resonance lines, even in fields with relatively poor homogeneity. The narrow linewidths result in enhanced signal-to-noise ratio and spatial resolution for a fixed strength of the magnetic field gradients used to encode the image. We present two-dimensional images of phantoms and pepper slices, obtained in typical magnetic field gradients of 100 fYT/m, with a spatial resolution of about 1mm. We further demonstrate a slice-selected image of an intact pepper. By varying the time delay between removal of the polarizing field and initiation of the spin echo sequence we acquire T1-weighted contrast images of water phantoms, some of which are doped with a paramagnetic salt; here, T1 is the nuclear spin-lattice relaxation time. The techniques presented here could readily be adapted to existing multichannel SQUID systems used for magnetic source imaging of brain signals. Further potential applications include low-cost systems for tumor screening and imaging peripheral regions of the body.

  2. A New Wideband Circularly Polarized Dielectric Resonator Antenna

    Directory of Open Access Journals (Sweden)

    M. Khalily

    2014-04-01

    Full Text Available A wideband and compact circularly polarized (CP C-shaped dielectric resonator antenna (DRA is presented. The proposed C-shaped DR is excited by a simple stripe line connected to a coplanar waveguide (CPW feeding line. The C-shaped DRA is circularly polarized with 19% axial ratio (AR bandwidth. It is found that the CP bandwidth can be expanded by using a narrow short circuit strip. The final design achieves CP with 50% AR bandwidth. The proposed circularly polarized DRA (CPDRA with good radiation characteristics offers an impedance bandwidth of 58% between 3.45 and 6.26 GHz for VSWR ≤ 2. The proposed DRA is fabricated and tested. Very good agreement between simulated and measured results is obtained.

  3. Searching sequences of resonant orbits between a spacecraft and Jupiter

    International Nuclear Information System (INIS)

    This research shows a study of the dynamical behavior of a spacecraft that performs a series of close approaches with the planet Jupiter. The main idea is to find a sequence of resonant orbits that allows the spacecraft to stay in the region of the space near the orbit of Jupiter around the Sun gaining energy from each passage by the planet. The dynamical model considers the existence of only two massive bodies in the systems, which are the Sun and Jupiter. They are assumed to be in circular orbits around their center of mass. Analytical equations are used to obtain the values of the parameters required to get this sequence of close approaches. Those equations are useful, because they show which orbits are physically possible when taking into account that the periapsis distances have to be above the surface of the Sun and that the closest approach distances during the passage by Jupiter have to be above its surface

  4. A resonance ionization imaging detector based on cesium atomic vapor

    International Nuclear Information System (INIS)

    A novel Cs resonance ionization imaging detector (RIID) has been developed and evaluated. The detector is capable of two-dimensional imaging with high spectral resolution, which is determined by the Doppler broadened atomic linewidth of Cs at given temperature. Ionization schemes of Cs have been investigated using dye and color center tunable lasers pumped by an excimer laser and by a Nd:YAG laser. It has been experimentally shown that the most efficient ionization scheme for Cs RIID should include a three-step excitation/ionization ladder, for example, with transitions at λ1=852.11 (852.113) nm, λ2=917.22 (917.2197) nm, and λ3=1064 nm. The imaging capabilities of the detector have been evaluated using a simpler two-step ionization scheme with wavelengths λ1=852.11 nm and λ2=508 nm

  5. A resonance ionization imaging detector based on cesium atomic vapor

    Science.gov (United States)

    Temirov, J. P.; Chigarev, N. V.; Matveev, O. I.; Omenetto, N.; Smith, B. W.; Winefordner, J. D.

    2004-05-01

    A novel Cs resonance ionization imaging detector (RIID) has been developed and evaluated. The detector is capable of two-dimensional imaging with high spectral resolution, which is determined by the Doppler broadened atomic linewidth of Cs at given temperature. Ionization schemes of Cs have been investigated using dye and color center tunable lasers pumped by an excimer laser and by a Nd:YAG laser. It has been experimentally shown that the most efficient ionization scheme for Cs RIID should include a three-step excitation/ionization ladder, for example, with transitions at λ1=852.11 (852.113) nm, λ2=917.22 (917.2197) nm, and λ3=1064 nm. The imaging capabilities of the detector have been evaluated using a simpler two-step ionization scheme with wavelengths λ1=852.11 nm and λ2=508 nm.

  6. Resonant tunnel magnetoresistance in a double magnetic tunnel junction

    KAUST Repository

    Useinov, Arthur

    2011-08-09

    We present quasi-classical approach to calculate a spin-dependent current and tunnel magnetoresistance (TMR) in double magnetic tunnel junctions (DMTJ) FML/I/FMW/I/FMR, where the magnetization of the middle ferromagnetic metal layer FMW can be aligned parallel or antiparallel with respect to the fixed magnetizations of the left FML and right FMR ferromagnetic electrodes. The transmission coefficients for components of the spin-dependent current, and TMR are calculated as a function of the applied voltage. As a result, we found a high resonant TMR. Thus, DMTJ can serve as highly effective magnetic nanosensor for biological applications, or as magnetic memory cells by switching the magnetization of the inner ferromagnetic layer FMW.© Springer Science+Business Media, LLC 2011.

  7. Experimental studies on perturbed acoustic resonant spectroscopy by a small rock sample in a cylindrical cavity

    Institute of Scientific and Technical Information of China (English)

    CHEN; Dehua; WANG; Xiuming; CONG; Jiansheng; XU; Delong; SONG; Yanjie; MA; Shuilong

    2006-01-01

    A measurement system for acoustic resonant spectroscopy (ARS) is established,and the effects of resonant cavity geometry,inner perturbation samples and environmental temperature on the ARS are investigated.The ARSs of the small samples with various sizes and acoustic properties are measured.The results show that at the normal pressure,the resonant frequency decreases gradually with the increase of liquid temperature in the cylindrical cavity,while the resonant amplitude increases.At certain pressure and temperature,both the resonant frequency and the amplitude decrease greatly when there exist air bubbles inside the cavity fluid.The ARS is apparently affected by the sample porosity and the sample location in the resonant cavity.At the middle of the cavity,the resonant frequencies reach their maximum values for all of the measurement samples.The resonant frequencies of the porous rock samples are smaller than those of the compacted samples if other acoustic parameters are the same.As the sample is moved from the top to the middle of the cavity along its axis,the resonant amplitude increases gradually for the compacted rocks while decreases for the unconsolidated rocks.Furthermore,the resonant amplitude increases firstly and then decreases if the porosity of the rock sample is relatively small.In addition,through the comparisons between the experimental and theoretical results,it is found that the effects of the acoustic parameters and sizes of the samples and the size of the cylindrical cavity on the laboratory results agree well with the theoretical ones qualitatively.These results may provide basic reference for the experiment study of rock acoustic properties in a low frequency using ARS.

  8. Cyclotron resonance maser experiments in a bifilar helical waveguide

    Science.gov (United States)

    Aharony; Drori; Jerby

    2000-11-01

    Oscillator and amplifier cyclotron-resonance-maser (CRM) experiments in a spiral bifilar waveguide are presented in this paper. The slow-wave CRM device employs a low-energy low-current electron beam (2-12 keV, approximately 0.5 A). The pitch angle of the helical waveguide is relatively small; hence, the phase velocity in this waveguide, V(ph) congruent with0.8c (where c is the speed of light), is much faster than the axial velocity of the electrons, V(ez)traveling-wave-tube-type interactions are eliminated in this device. According to the CRM theory, the dominant effect in this operating regime, V(ez)2%). The wide tunable range of this CRM device due to the nondispersive bifilar helix is discussed.

  9. Magnetic resonance imaging of spinal cord trauma: a pictorial essay

    Energy Technology Data Exchange (ETDEWEB)

    Demaerel, Philippe [University Hospitals Gasthuisberg, Department of Radiology, Leuven (Belgium)

    2006-04-15

    Assessing a patient with clinical signs of acute spinal cord trauma is an emergency. A radiological work-up is crucial in determining management, and magnetic resonance imaging (MRI) is the modality of choice. It should therefore be performed immediately, preferably within 3 hours, even when plain radiography does not show an abnormality. By choosing an appropriate imaging protocol, it is possible to assess the spinal cord, joints, muscles, ligaments and bone marrow of the spine. Moreover, early MRI findings assist in determining functional prognosis. A major limitation to early MRI is that the examination is usually restricted to stable trauma patients because of the difficulties in monitoring ventilated patients during scanning. However, when an anaesthesiologist with experience in MRI and MR-compatible monitoring equipment is available, even these patients can be safely examined. MRI is also indicated for the evaluation of patients with late complications and sequelae following spinal cord trauma, since many of these chronic lesions are potentially treatable. (orig.)

  10. Magnetic resonance imaging of spinal cord trauma: a pictorial essay

    International Nuclear Information System (INIS)

    Assessing a patient with clinical signs of acute spinal cord trauma is an emergency. A radiological work-up is crucial in determining management, and magnetic resonance imaging (MRI) is the modality of choice. It should therefore be performed immediately, preferably within 3 hours, even when plain radiography does not show an abnormality. By choosing an appropriate imaging protocol, it is possible to assess the spinal cord, joints, muscles, ligaments and bone marrow of the spine. Moreover, early MRI findings assist in determining functional prognosis. A major limitation to early MRI is that the examination is usually restricted to stable trauma patients because of the difficulties in monitoring ventilated patients during scanning. However, when an anaesthesiologist with experience in MRI and MR-compatible monitoring equipment is available, even these patients can be safely examined. MRI is also indicated for the evaluation of patients with late complications and sequelae following spinal cord trauma, since many of these chronic lesions are potentially treatable. (orig.)

  11. Electron cyclotron resonance breakdown studies in a linear plasma system

    Indian Academy of Sciences (India)

    Vipin K Yadav; K Sathyanarayana; D Bora

    2008-03-01

    Electron cyclotron resonance (ECR) plasma breakdown is studied in a small linear cylindrical system with four different gases - hydrogen, helium, argon and nitrogen. Microwave power in the experimental system is delivered by a magnetron at 2.45 ± 0.02 GHz in TE10 mode and launched radially to have extra-ordinary (X) wave in plasma. The axial magnetic field required for ECR in the system is such that the fundamental ECR surface ( = 875.0 G) resides at the geometrical centre of the plasma system. ECR breakdown parameters such as plasma delay time and plasma decay time from plasma density measurements are carried out at the centre using a Langmuir probe. The operating parameters such as working gas pressure (1 × 10-5 -1 × 10-2 mbar) and input microwave power (160{800 W) are varied and the corresponding effect on the breakdown parameters is studied. The experimental results obtained are presented in this paper.

  12. Power efficiency improvement of a multi-oscillated current resonant type DC-DC converter

    OpenAIRE

    Sato, Tadahiko; Matsuo, Hirofumi; Ota, Hiroyuki; Ishizuka, Yoichi; Higashi, Nobuhiro

    2009-01-01

    This paper deals with an improvement of a power efficiency of a multi-oscillated current resonant type DC-DC converter. The current resonant type converter employs generally the pulse frequency modulation and its magnetizing inductance is set relatively low. For this reason, the magnetizing current through the converter causes a power loss under a light load. In order to solve this problem, a multi-oscillated current resonant type DC-DC converter has been proposed, and revealed the advantage ...

  13. The dynamic mechanical characteristics of a resonating microbridge mass-flow sensor

    OpenAIRE

    Geijselaers, H.J.M.; Tijdeman, H.

    1991-01-01

    This paper gives an explanation of the dynamic mechanical behaviour of a resonating microbridge mass-flow sensor. A rise in the average temperature of the bridge initially results in a reduction of the resonance frequency. Upon further temperature rise, a reversal occurs and the resonance frequency starts rising too. The dynamic behaviour in this case is found to be governed by static buckling. This phenomenon is analysed, first using a finite-element model and then with an approximate analyt...

  14. Temperature compensation method for the resonant frequency of a differential vibrating accelerometer using electrostatic stiffness control

    Science.gov (United States)

    Lee, Jungshin; Rhim, Jaewook

    2012-09-01

    Differential vibrating accelerometer (DVA) is a resonant-type sensor which detects the change in the resonant frequency in the presence of acceleration input, i.e. inertial loading. However, the resonant frequency of micromachined silicon resonators is sensitive to the temperature change as well as the input acceleration. Therefore, to design a high-precision vibrating accelerometer, the temperature sensitivity of the resonant frequency has to be predicted and compensated accurately. In this study, a temperature compensation method for resonant frequency is proposed which controls the electrostatic stiffness of the dual-ended tuning fork (DETF) using the temperature-dependent dc voltage between the parallel plate electrodes. To do this, the electromechanical model is derived first to predict the change in the electrostatic stiffness and the resonant frequency resulting from the dc voltage between the resonator and the electrodes. Next, the temperature sensitivity of the resonant frequency is modeled, estimated and compared with the measured values. Then it is shown that the resonant frequency of the DETF can be kept constant in the operating temperature range by applying the temperature-dependent driving voltage to the parallel plate electrodes. The proposed method is validated through experiment.

  15. Temperature compensation method for the resonant frequency of a differential vibrating accelerometer using electrostatic stiffness control

    International Nuclear Information System (INIS)

    Differential vibrating accelerometer (DVA) is a resonant-type sensor which detects the change in the resonant frequency in the presence of acceleration input, i.e. inertial loading. However, the resonant frequency of micromachined silicon resonators is sensitive to the temperature change as well as the input acceleration. Therefore, to design a high-precision vibrating accelerometer, the temperature sensitivity of the resonant frequency has to be predicted and compensated accurately. In this study, a temperature compensation method for resonant frequency is proposed which controls the electrostatic stiffness of the dual-ended tuning fork (DETF) using the temperature-dependent dc voltage between the parallel plate electrodes. To do this, the electromechanical model is derived first to predict the change in the electrostatic stiffness and the resonant frequency resulting from the dc voltage between the resonator and the electrodes. Next, the temperature sensitivity of the resonant frequency is modeled, estimated and compared with the measured values. Then it is shown that the resonant frequency of the DETF can be kept constant in the operating temperature range by applying the temperature-dependent driving voltage to the parallel plate electrodes. The proposed method is validated through experiment. (paper)

  16. Quantum phase transition of light in a 1-D photon-hopping-controllable resonator array

    CERN Document Server

    Wu, Chun-Wang; Deng, Zhi-Jiao; Dai, Hong-Yi; Chen, Ping-Xing; Li, Cheng-Zu

    2011-01-01

    We give a concrete experimental scheme for engineering the insulator-superfluid transition of light in a one-dimensional (1-D) array of coupled superconducting stripline resonators. In our proposed architecture, the on-site interaction and the photon hopping rate can be tuned independently by adjusting the transition frequencies of the charge qubits inside the resonators and at the resonator junctions, respectively, which permits us to systematically study the quantum phase transition of light in a complete parameter space. By combining the techniques of photon-number-dependent qubit transition and fast read-out of the qubit state using a separate low-Q resonator mode, the statistical property of the excitations in each resonator can be obtained with a high efficiency. An analysis of the various decoherence sources and disorders shows that our scheme can serve as a guide to coming experiments involving a small number of coupled resonators.

  17. The slope effect of a capacitive resonator profile fabricated by a DRIE process on the performance of an MEMS disk resonator

    International Nuclear Information System (INIS)

    The thickness of a capacitive disk resonator can be increased by selecting a deep reactive ion etching (DRIE) process for reducing motional resistance. However, the DRIE process sometimes causes MEMS capacitive resonators to have a non-ideal profile. In this paper, the slope effect of a resonator profile fabricated by a DRIE process on the capacitance, electrostatic force, electrical stiffness, motional resistance and output current of the capacitive resonator is analyzed. The relation curves between these parameters and the sloped angle are obtained theoretically. The results show that the capacitance, electrostatic force, electrical stiffness and output current decrease as the sloped angle increases, but the motional resistance obviously increases. By capturing the electric field distribution of a capacitive resonator with different ratios of the gap to thickness by using FEM software ANSYS, the effects of slope angle and thickness on the natural frequency of the resonator are investigated. The analyzed results can provide the theoretical basis for designing high-performance MEMS disk resonators fabricated by the DRIE process. (paper)

  18. Diffusion magnetic resonance imaging for Brainnetome: A critical review

    Institute of Scientific and Technical Information of China (English)

    Nianming Zuo; Jian Cheng; Tianzi Jiang

    2012-01-01

    Increasing evidence shows that the human brain is a highly self-organized system that shows attributes of smallworldness,hierarchy and modularity.The "connectome" was conceived several years ago to identify the underpinning physical connectivities of brain networks.The need for an integration of multi-spatial and -temporal approaches is becoming apparent.Therefore,the "Brainnetome" (brain-net-ome) project was proposed.Diffusion magnetic resonance imaging (dMRI)is a non-invasive way to study the anatomy of brain networks.Here,we review the principles of dMRI,its methodologies,and some of its clinical applications for the Brainnetome.Future research in this field is discussed.

  19. Current at a distance and resonant transparency in Weyl semimetals

    Science.gov (United States)

    Stern, Ady; Baum, Yuval; Berg, Erez; Parameswaran, Siddharth

    Surface Fermi arcs are the most prominent manifestation of the topological nature of Weyl semimetals. In the presence of a static magnetic field oriented perpendicular to the sample surface, their existence leads to unique inter-surface cyclotron orbits. We propose two experiments which directly probe the Fermi arcs: a magnetic field dependent non-local DC voltage and sharp resonances in the transmission of electromagnetic waves at frequencies controlled by the field. We show that these experiments are insensitive to small momentum scattering and do not rely on quantum mechanical phase coherence, which renders them far more robust and experimentally accessible than quantum effects. We also comment on the applicability of these ideas to Dirac semimetals.

  20. A coupling method of subgroup and wavelet expansion for the resonance parameter calculation

    International Nuclear Information System (INIS)

    Owing to their geometric flexibility, subgroup method and wavelet expansion method have become attractive approaches to obtain effective self-shielding microscopic cross sections within resonance energy groups for geometrically complex problems. However, the subgroup method is good in the dense resonance range, while the wavelet expansion method is good in the sparse resonance range. In order to get the resonance parameter in the whole resonance energy range more accurately and effectively, this paper developed a new coupling resonance calculation model based on subgroup method and wavelet expansion method. In this coupling model, the subgroup method is employed to handle the higher resonance energy groups, and the wavelet expansion method is employed to handle the lower resonance energy groups. At the coupling interface, they are coupled by transferring scattering source. In order to verify the coupling model, a series of benchmark problems are calculated in this paper. It is demonstrated that compared with subgroup method and wavelet expansion method respectively, this coupling resonance model has the ability to provide more exactly self-shielding microscopic cross sections in the whole resonance energy range while keeping enough efficiency. (author)

  1. Air damping of micro bridge resonator vibrating close to a surface with a moderate distance

    International Nuclear Information System (INIS)

    The vibration of micro resonators is strongly influenced by the hydrodynamics of the surrounding fluid in the vicinity of a rigid wall. While most prior efforts to model this hydrodynamic loading have focused on squeeze film damping with very narrow gaps, in many practical applications, the resonators vibrate close to a surface with a moderate distance. Two recently developed models which deal with this problem are reviewed. Experiments by using a micro bridge resonator with a big range of gaps are performed at controlled gas pressures, and are compared with predictions from these theoretical models. The unsteady Navier–Stokes model yields the best agreement with experiments. (paper)

  2. Magnetotunneling spectroscopy of polarons in a quantum well of a resonant-tunneling diode

    International Nuclear Information System (INIS)

    Resonant tunneling of electrons is thoroughly studied in in-plane magnetic fields. Anticrossing is revealed in a spectrum of two-dimensional electrons at energies of optical phonons. The magnetic field changes the momentum of tunneling electrons and causes a voltage shift of a resonance in the tunnel spectra in accordance with the electron dispersion curve. Anticrossing is clearly observed in second derivative current-voltage characteristics of a resonant tunneling diode made of a double-barrier Al0.4Ga0.6As/GaAs heterostructure.

  3. Realization of a Double-Barrier Resonant Tunneling Diode for Cavity Polaritons

    OpenAIRE

    Nguyen, Hai Son; Vishnevsky, Dmitry; Sturm, Chris; Tanese, Dimitrii; Solnyshkov, Dmitry; Galopin, Elisabeth; Lemaître, Aristide; Sagnes, Isabelle; Amo, Alberto; Malpuech, Guillaume; Bloch, Jacqueline

    2013-01-01

    We report on the realization of a double barrier resonant tunneling diode for cavity polaritons, by lateral patterning of a one-dimensional cavity. Sharp transmission resonances are demonstrated when sending a polariton flow onto the device. We use a non-resonant beam can be used as an optical gate and control the device transmission. Finally we evidence distortion of the transmission profile when going to the high density regime, signature of polariton-polariton interactions.

  4. A novel RF resonator for human-body MRI at 3 T

    Science.gov (United States)

    Son, Hyeok-Woo; Cho, Young-Ki; Yoo, Hyoungsuk

    2014-03-01

    A square-slot-loaded (SSL) radio-frequency (RF) resonator using a microstrip transmission line (MTL) is designed for human-body magnetic resonance imaging (MRI) at 3 T MRI. The SSL RF resonator shows improved RF magnetic fields resulting in more homogenous fields near the center of the phantom than traditional RF resonators using MTL. A multichannel body coil using the SSL RF resonators is also simulated and provides improved parallel excitation performance. In addition, RF shimming for homogenization can be effectively controlled by adjusting the inputs to the eight resonators. Numerical results are obtained by using a spherical phantom and a realistic human-body model at 3 T to calculate the B {1/+} fields.

  5. Resonance and interference phenomena in the photoionisation of a hydrogen atom in a uniform electric field

    International Nuclear Information System (INIS)

    The photoionisation cross section for a hydrogen atom placed in a uniform electric field is investigated as a function of the light frequency. Analytical formulae are obtained describing the cross section structure in various regions of photon energy and field strength. The Fano parametrisation of resonance peak is generalised for the overlapping resonance case. When the photon energy is close to the ionisation potential the resonance peaks are strongly asymmetrical. A comparison is made with experiments where the structure is observed in the photoionisation of sodium and rubidium atoms. (author)

  6. Cooling of a micro-mechanical resonator by the back-action of Lorentz force

    Science.gov (United States)

    Wang, Ying-Dan; Semba, K.; Yamaguchi, H.

    2008-04-01

    Using a semi-classical approach, we describe an on-chip cooling protocol for a micro-mechanical resonator by employing a superconducting flux qubit. A Lorentz force, generated by the passive back-action of the resonator's displacement, can cool down the thermal motion of the mechanical resonator by applying an appropriate microwave drive to the qubit. We show that this on-chip cooling protocol, with well-controlled cooling power and a tunable response time of passive back-action, can be highly efficient. With feasible experimental parameters, the effective mode temperature of a resonator could be cooled down by several orders of magnitude.

  7. Regge trajectory of the f0(500) resonance from a dispersive connection to its pole

    Energy Technology Data Exchange (ETDEWEB)

    Nebreda, J. [Kyoto University, Kyoto, 606-8502, Japan; Londergan, J. Timothy [Indiana University , Bloomington, IN; Pelaez, Jose R. [Universidad Complutense de Madrid, 28040, Spain; Szczepaniak, Adam P. [Indiana University , Bloomington, IN

    2014-11-01

    We report here our results on how to obtain the Regge trajectory of a resonance from its pole in a scattering process by imposing analytic constraints in the complex angular momentum plane. The method, suited for resonances that dominate an elastic scattering amplitude, has been applied to the ρ (770) and the f0(500) resonances. Whereas for the former we obtain a linear Regge trajectory, characteristic of ordinary quark-antiquark states, for the latter we find a non-linear trajectory with a much smaller slope at the resonance mass. This provides a strong indication of the non-ordinary nature of the sigma meson.

  8. Extrafetal Findings on Fetal Magnetic Resonance Imaging: A Pictorial Essay.

    Science.gov (United States)

    Epelman, Monica; Merrow, Arnold C; Guimaraes, Carolina V; Victoria, Teresa; Calvo-Garcia, Maria A; Kline-Fath, Beth M

    2015-12-01

    Although US is the mainstay of fetal imaging, magnetic resonance imaging (MRI) has become an invaluable adjunct in recent years. MRI offers superb soft tissue contrast that allows for detailed evaluation of fetal organs, particularly the brain, which enhances understanding of disease severity. MRI can yield results that are similar to or even better than those of US, particularly in cases of marked oligohydramnios, maternal obesity, or adverse fetal positioning. Incidentally detected extrafetal MRI findings are not uncommon and may affect clinical care. Physicians interpreting fetal MRI studies should be aware of findings occurring outside the fetus, including those structures important for the pregnancy. A systematic approach is necessary in the reading of such studies. This helps to ensure that important findings are not missed, appropriate clinical management is implemented, and unnecessary follow-up examinations are avoided. In this pictorial essay, the most common extrafetal abnormalities are described and illustrated. PMID:26614136

  9. Analytical model of a giant magnetostrictive resonance transducer

    Science.gov (United States)

    Sheykholeslami, M.; Hojjat, Y.; Ansari, S.; Cinquemani, S.; Ghodsi, M.

    2016-04-01

    Resonance transducers have been widely developed and studied, as they can be profitably used in many application such as liquid atomizing and sonar technology. The active element of these devices can be a giant magnetostrictive material (GMM) that is known to have significant energy density and good performance at high frequencies. The paper introduces an analytical model of GMM transducers to describe their dynamics in different working conditions and to predict any change in their performance. The knowledge of the transducer behavior, especially in operating conditions different from the ideal ones, is helpful in the design and fabrication of highly efficient devices. This transducer is design to properly work in its second mode of vibration and its working frequency is around 8000 Hz. Most interesting parameters of the device, such as quality factor, bandwidth and output strain are obtained from theoretical analysis.

  10. Magnetic resonance imaging in schizophrenia: a morphometric study

    International Nuclear Information System (INIS)

    Thirty-three patients with chronic schizophrenia and 21 normal subjects were submitted to magnetic resonance imaging studies using a 1.5 T scanner. Axial and coronal T 2-weighted images were obtained. The volumes of the brain, intracranial, supratentorial, infratentorial and the total, ventricular and subarachnoid cerebrospinal fluid volumes were measured using semi-automated morphometric methods. The volumes of the amygdala-hippocampus complex, para hippocampal gyrus cortex, putamen, globus pallidus, temporal lobe, gray and white matter of temporal lobe were also measured. These volumes were normalized using the intracranial volume as reference. The most relevant findings observed were reduced brain volume and increased total, ventricular and subarachnoid cerebrospinal fluid volumes in patients with schizophrenia when compared to the controls. Patients with schizophrenia had also smaller amygdala-hippocampus complexes, temporal lobes and temporal lobe white matter than the controls, as well as increased putamen volumes. (author)

  11. Magnification of mantle resonance as a cause of tectonics

    CERN Document Server

    Omerbashich, M

    2006-01-01

    Variance spectral analysis of superconducting gravimeter (SG) decadal data (noise inclusive) suggests conceptually that the Earth tectonogenesis could in part be based on magnification of the mantle mechanical resonance, in addition to previously hypothesized causes. Aanalogously to the atmospheric tidal forcing of global high frequency free oscillation, I propose that the Moon synodically recurring pull could likewise drive the long-periodic (12 to 120 minutes) oscillation of the Earth. To demonstrate this, I show that the daily magnitudes of mass (gravity) oscillation, as a relative measure of the Earth kinetic energy, get synodically periodic while correlating up to 0.97 with seismic energies on the day of shallow and 3 days before deep earthquakes. The forced oscillator equations for the mantle usual viscosity and the Earth springtide and grave mode periods successfully model an identical 3 days phase. Finally, whereas reports on gravest earthquakes (of around M9.5) put the maximum coseismic displacement ...

  12. Stochastic resonance in a parallel array of linear elements

    Institute of Scientific and Technical Information of China (English)

    Dong Xiao-Juan

    2009-01-01

    This paper studies stochastic resonance (SR) phenomenon in a parallel array of linear elements with noise. Employing the signal-to-noise ratio (SNR) theory, it obtains the output SNR, and investigates the effects on the output SNR of the system with signal-independent noise and signal-dependent noise respectively. Numerical results show: the curve of the output SNR is monotone with signal-independent noise; whereas SR appears with signal-dependent noise. Moreover, the output SNR enhances rapidly with the increase of N which is the number of elements in this parallel array linear system. This result may provide smart array of simple linear sensors which are capable of acting as noise-aided amplifiers.

  13. Mapping the sensitivity of split ring resonators using a localized analyte

    OpenAIRE

    Sharp, Graham J.; Vilhena, Henrique; Lahiri, Basudev; McMeekin, Scott G.; De La Rue, Richard M.; Johnson, Nigel P.

    2016-01-01

    Split ring resonator (SRR) based metamaterials have frequently been demonstrated for use as optical sensors of organic materials. This is made possible by matching the wavelength of the SRR plasmonic resonance with a molecular resonance of a specific analyte, which is usually placed on top of the metal structure. However, systematic studies of SRRs that identify the regions that exhibit a high electric field strength are commonly performed using simulations. In this paper we demonstrate that ...

  14. Set up of a method for the adjustment of resonance parameters on integral experiments

    International Nuclear Information System (INIS)

    Resonance parameters for actinides play a significant role in the neutronic characteristics of all reactor types. All the major integral parameters strongly depend on the nuclear data of the isotopes in the resonance-energy regions.The author sets up a method for the adjustment of resonance parameters taking into account the self-shielding effects and restricting the cross section deconvolution problem to a limited energy region. (N.T.)

  15. A quasioptically stabilized resonant-tunneling-diode oscillator for the millimeter- and submillimeter-wave regions

    Science.gov (United States)

    Brown, Elliott R.; Parker, Christopher D.; Molvar, Karen M.; Stephan, Karl D.

    1992-01-01

    A semiconfocal open-cavity resonator has been used to stabilize a resonant-tunneling-diode waveguide oscillator at frequencies near 100 GHz. The high quality factor of the open cavity resulted in a linewidth of approximately 10 kHz at 10 dB below the peak, which is about 100 times narrower than the linewidth of an unstabilized waveguide oscillator. This technique is well suited for resonant-tunneling-diode oscillators in the submillimeter-wave region.

  16. Ultracompact resonator with high quality-factor based on a hybrid grating structure

    DEFF Research Database (Denmark)

    Taghizadeh, Alireza; Mørk, Jesper; Chung, Il-Sug

    2015-01-01

    We numerically investigate the properties of a hybrid grating structure acting as a resonator with ultrahigh quality factor. This reveals that the physical mechanism responsible for the resonance is quite different from the conventional guided mode resonance (GMR). The hybrid grating consists...... of a subwavelength grating layer and an un-patterned high-refractive-index cap layer, being surrounded by low index materials. Since the cap layer may include a gain region, an ultracompact laser can be realized based on the hybrid grating resonator, featuring many advantages over high-contrast-grating resonator...... lasers. The effect of fabrication errors and finite size of the structure is investigated to understand the feasibility of fabricating the proposed resonator....

  17. Realizing of plasmon Fano resonance with a metal nanowall moving along MIM waveguide

    Science.gov (United States)

    Chen, Fang; Yao, Duanzheng

    2016-06-01

    A larger number of complicated plasmonic nanostructures have been realized to exhibit Fano interference. In this paper, we demonstrate a simple nanostructure, side coupled waveguide resonator system with a metal nanowall located in the metal-insulator-metal waveguide (MIM), which can also achieve multiple plasmonic Fano resonance. In the proposed nanostructure, the asymmetric line shape originates from the interference between the slot resonator and the new resonator. Therefore, the Fano line shape can be actively controlled by the phase difference of the two resonators and the thickness of the metal nanowall. A scattering matrix method is used to calculate the transmission spectra. Results obtained by the scattering matrix theory are consistent with those from the finite-difference time-domain simulations (FDTD). Moreover, Fano resonances in the proposed structure show high sensitivity, which may have important application in plasmonic nanosensor and modulator.

  18. A Generalized Approach for the Steady-State Analysis of Dual-Bridge Resonant Converters

    Directory of Open Access Journals (Sweden)

    Gao-Yuan Hu

    2014-11-01

    Full Text Available In this paper, a dual-bridge DC/DC resonant converter with a generalized series and parallel resonant tank is analyzed. A general approach based on Fundamental Harmonic Approximation is used to find the universal steady-state solutions. The analysis results for particular resonant tank configurations are exemplified with several typical resonant tank configurations respectively. The corresponded soft-switching conditions are discussed too. To illustrate the usefulness of the generalized approach, a dual-bridge (LC(L-type resonant converter working in below resonance mode is designed based on the analysis results. Finally, simulation and experimental plots of the design example are included to evaluate the validity and the accuracy of the proposed analysis approach.

  19. Transient processes under dynamic excitation of a coherent population trapping resonance

    Science.gov (United States)

    Khripunov, S. A.; Radnatarov, D. A.; Kobtsev, S. M.; Yudin, V. I.; Taichenachev, A. V.; Basalaev, M. Yu; Balabas, M. V.; Andryushkov, V. A.; Popkov, I. D.

    2016-07-01

    It is shown for the first time that under dynamic excitation of a coherent population trapping resonance in Rb vapours at different bichromatic pump modulation frequencies from a few tens of hertz and higher, the resonance is dramatically deformed as a result of emerging intensity oscillations of radiation transmitted through an Rb vapour cell. A significant change in the shape of the resonance under its dynamic excitation is confirmed experimentally and theoretically. A possible impact of the identified changes in the shape of the coherent population trapping resonance on the stability of an atomic clock is qualitatively discussed.

  20. Design and fabrication of a phononic-crystal-based Love wave resonator in GHz range

    OpenAIRE

    Ting-Wei Liu; Yao-Chuan Tsai; Yu-Ching Lin; Takahito Ono; Shuji Tanaka; Tsung-Tsong Wu

    2014-01-01

    This paper presents a method for designing and fabricating a Love wave resonator utilizing the phononic crystal (PC) as the reflectors. The PCs were formed by depositing 2D, periodically etched silica film on a quartz substrate. We analyzed the PC structure, and within its partial bandgap we designed a one-port resonator that contained a set of inter-digital transducer (IDT) inside the resonant cavity bonded by two PC arrays. With sub-micrometer structures, the resonator was designed to opera...

  1. Laser Stabilization on a Fiber Ring Resonator and Application to RF Filtering

    OpenAIRE

    Merrer, Pierre-Henri; Llopis, Olivier; Cibiel, Gilles

    2008-01-01

    International audience The potential of optical fiber ring resonators for RF or microwave signals filtering on optical carriers is demonstrated on a short length high Q resonator. The problem of the frequency shift due to the resonator self heating with the optical power is solved thanks to a Pound-Drever feedback loop. A multi frequency RF filter is obtained, with a frequency step of 205 MHz between resonances, and a 3 dB bandwidth of 2.4 MHz. This corresponds to the computed optical reso...

  2. Ultrafast Reversal of a Fano Resonance in a Plasmon-Exciton System

    OpenAIRE

    Shah, Raman A.; Scherer, Norbert F.; Pelton, Matthew; Gray, Stephen K.

    2013-01-01

    When a two-level quantum dot and a plasmonic metal nanoantenna are resonantly coupled by the electromagnetic near field, the system can exhibit a Fano resonance, resulting in a transparency dip in the optical spectrum of the coupled system. We calculate the nonlinear response of such a system, for illumination both by continuous-wave and ultrafast pulsed lasers, using both a cavity quantum electrodynamics and a semiclassical coupled-oscillator model. For the experimentally relevant case of me...

  3. Directional dependence of vortex core resonance in a square-shaped ferromagnetic dot

    Science.gov (United States)

    Cui, Xiaomin; Yakata, Satoshi; Kimura, Takashi

    2016-01-01

    The resonant property of the magnetic vortex confined in a square-shaped ferromagnetic dot has been investigated. We showed that the field dependence of the resonant frequency has a unique directional dependence originating from a four-fold rotational symmetry of the square. The resonant frequency is found to be strongly modulated by the magnetic field along the diagonal direction although the magnetic field applied along the side of the square hardly modified the resonant frequency. The modulation ratio of the resonant frequency defined by the ratio between minimum and maximum frequencies for the vortex resonance was found to be tuned by the lateral dimension of the square. These unique frequency tunabilities controlled by the magnitude and the direction of the magnetic field may provide additional functions in the application of the magnetic vortex systems.

  4. A nonlinear plasmonic resonator for three-state all-optical switching

    KAUST Repository

    Amin, Muhammad

    2014-01-01

    A nonlinear plasmonic resonator design is proposed for three-state all-optical switching at frequencies including near infrared and lower red parts of the spectrum. The tri-stable response required for three-state operation is obtained by enhancing nonlinearities of a Kerr medium through multiple (higher order) plasmons excited on resonator\\'s metallic surfaces. Indeed, simulations demonstrate that exploitation of multiple plasmons equips the proposed resonator with a multi-band tri-stable response, which cannot be obtained using existing nonlinear plasmonic devices that make use of single mode Lorentzian resonances. Multi-band three-state optical switching that can be realized using the proposed resonator has potential applications in optical communications and computing. © 2014 Optical Society of America.

  5. Topological effects in anisotropy-induced nano-fano resonance of a cylinder.

    Science.gov (United States)

    Gao, Dongliang; Gao, Lei; Novitsky, Andrey; Chen, Hongli; Luk'yanchuk, Boris

    2015-09-01

    We demonstrate that optical Fano resonance can be induced by the anisotropy of a cylinder rather than frequency selection under the resonant condition. A tiny perturbation in anisotropy can result in a giant switch in the principal optic axis near plasmon resonance. Such anisotropy-induced Fano resonance shows fast reversion between forward and backward scattering at the lowest-energy interference. The near and far fields of the particle change dramatically around Fano resonance. The topology of optical singular points and the trajectory of energy flux distinctly reveal the interaction between the incident wave and the localized surface plasmons, which also determine the far-field scattering pattern. The anisotropy-induced Fano resonance and its high sensitivity open new perspectives on light-matter interactions and promise potential applications in biological sensors, optical switches, and optomechanics. PMID:26368737

  6. Three-Photon Resonant Nondegenerate Six-Wave Mixing in a Dressed Atomic System

    Institute of Scientific and Technical Information of China (English)

    SUN Jiang; FU Guang-Sheng; SU Hong-Xin; ZUO Zhan-Chun; WU Ling-An; FU Pan-Ming

    2008-01-01

    We report a three-photon resonant nondegenerate six-wave mixing (NSWM) in a dressed cascade five-level system.It has advantages that phase match condition is not stringent and NSWM signal is enhanced tremendously due to the multiple resonance with the atomic transition frequencies. In the presence of a strong coupling field,the threephoton resonant NSWM spectrum exhibits Autler-Townes splitting. This technique provides a spectroscopic tool for measuring not only the resonant frequency and dephasing rate but also the transition dipole moment between two highly excited atomic states.

  7. Disorder effect of resonant spin Hall effect in a tilted magnetic field

    OpenAIRE

    Shen, SQ; Zhang, FC; Jiang, ZF

    2009-01-01

    We study the disorder effect of resonant spin Hall effect in a two-dimensional electron system with Rashba coupling in the presence of a tilted magnetic field. The competition between the Rashba coupling and the Zeeman coupling leads to the energy crossing of the Landau levels, which gives rise to the resonant spin Hall effect. Utilizing the Streda's formula within the self-consistent Born approximation, we find that the impurity scattering broadens the energy levels and the resonant spin Hal...

  8. Nuclear Tuning and Detuning of the Electron Spin Resonance in a Quantum Dot: Theoretical Consideration

    OpenAIRE

    Danon, J.; Nazarov, Y. V.

    2008-01-01

    We study nuclear spin dynamics in a quantum dot close to the conditions of electron spin resonance. We show that at a small frequency mismatch, the nuclear field detunes the resonance. Remarkably, at larger frequency mismatch, its effect is opposite: The nuclear system is bistable, and in one of the stable states, the field accurately tunes the electron spin splitting to resonance. In this state, the nuclear field fluctuations are strongly suppressed, and nuclear spin relaxation is accelerated.

  9. A new type of resonant neutrino conversions induced by magnetic fields

    CERN Document Server

    Sahu, S; Valle, José W F

    1995-01-01

    We consider resonant neutrino conversions in magnetised matter, such as a degenerate electron gas. We show how magnetisation effects caused by axial vector interactions of neutrinos with the charged leptons in the medium can induce a new type of resonant neutrino conversion which may occur even in situations where the MSW effect does not occur, such as the case of degenerate or inverted neutrino mass spectra. Our new resonance may simultaneously affect anti-neutrino \\bar{\

  10. Applications and Methods of Operating a Three-dimensional Nano-electro-mechanical Resonator and Related Devices

    Science.gov (United States)

    Kaul, Anupama B. (Inventor); Epp, Larry W. (Inventor); Bagge, Leif (Inventor)

    2013-01-01

    Carbon nanofiber resonator devices, methods for use, and applications of said devices are disclosed. Carbon nanofiber resonator devices can be utilized in or as high Q resonators. Resonant frequency of these devices is a function of configuration of various conducting components within these devices. Such devices can find use, for example, in filtering and chemical detection.

  11. Nonlinear frequency mixing in a resonant cavity: numerical simulations in a bubbly liquid.

    Science.gov (United States)

    Vanhille, Christian; Campos-Pozuelo, Cleofé; Sinha, Dipen N

    2014-12-01

    The study of nonlinear frequency mixing for acoustic standing waves in a resonator cavity is presented. Two high frequencies are mixed in a highly nonlinear bubbly liquid filled cavity that is resonant at the difference frequency. The analysis is carried out through numerical experiments, and both linear and nonlinear regimes are compared. The results show highly efficient generation of the difference frequency at high excitation amplitude. The large acoustic nonlinearity of the bubbly liquid that is responsible for the strong difference-frequency resonance also induces significant enhancement of the parametric frequency mixing effect to generate second harmonic of the difference frequency. PMID:25064635

  12. Multiphoton resonant ionization of a hydrogen-like atom by a strong electromagnetic field

    International Nuclear Information System (INIS)

    One studies multiquantum resonant ionization in case when intermediate bound state is a two-fold degenerate one. One derived expressions for energy and angular distribution of photoelectrons and quasi-classical formula for the total rate of resonant ionization. It is shown that depending on ratios between parameters the ionization rate may be both higher and lower than the rate of ionization in the typical case. A situation when possibility of resonant ionization is strongly suppressed is possible. It is shown, as well, that in the near-the-threshold one observes weaker dependence of probability of photoelectron escape on the angle in contrast to the case of ionization through nondegenerate level

  13. Current-induced resonant depinning of a transverse magnetic domain wall in a spin valve nanostrip

    Science.gov (United States)

    Metaxas, P. J.; Anane, A.; Cros, V.; Grollier, J.; Deranlot, C.; Lemaître, Y.; Xavier, S.; Ulysse, C.; Faini, G.; Petroff, F.; Fert, A.

    2010-11-01

    We study the impact of rf and dc currents on domain wall depinning in the soft layer of a 120 nm wide Co/Cu/NiFe spin valve nanostrip. A strong resonant reduction in the depinning field (from ˜75 to 25 Oe) is observed for rf currents near 3.5 GHz. Notably, the features of the resonant depinning depend not only on the rf current but also on the simultaneously applied dc current. Consequently, we discuss both the role of the adiabatic spin torque at resonance and that of the current generated Oersted fields.

  14. Planar modes free piezoelectric resonators using a phononic crystal with holes.

    Science.gov (United States)

    Aragón, J L; Quintero-Torres, R; Domínguez-Juárez, J L; Iglesias, E; Ronda, S; Montero de Espinosa, F

    2016-09-01

    By using the principles behind phononic crystals, a periodic array of circular holes made along the polarization thickness direction of piezoceramic resonators are used to stop the planar resonances around the thickness mode band. In this way, a piezoceramic resonator adequate for operation in the thickness mode with an in phase vibration surface is obtained, independently of its lateral shape. Laser vibrometry, electric impedance tests and finite element models are used to corroborate the performances of different resonators made with this procedure. This method can be useful in power ultrasonic devices, physiotherapy and other external medical power ultrasound applications where piston-like vibration in a narrow band is required. PMID:27387418

  15. Design and fabrication of a high performance resonant MEMS temperature sensor

    International Nuclear Information System (INIS)

    This paper presents a high performance MEMS temperature sensor comprised of a double-ended-tuning-fork (DETF) resonator and strain-amplifying beam structure. The temperature detection is based on the ‘thermal strain induced frequency variations’ of the DETF resonator. The major source of thermal strain leading to the frequency shifts is the difference in thermal expansion coefficients of the substrate and the device layers of the fabricated structures. By selecting the substrate as glass and the device layers as single crystal silicon, i.e. materials with different thermal expansion coefficients, the tines of the resonators are exposed to axial load with the changing temperature, which causes a change in the resonance frequency of the resonators. This resonance frequency shift can be related with the changing temperature by taking the thermal strain relations into consideration, which enables utilization of the resonator as a highly sensitive temperature sensor. The resonators used in this study have been fabricated by utilizing the advanced MEMS process that incorporates the simple silicon-on-glass process with the wafer level vacuum packaging Torunbalci et al (2015 J. Microelectromech. Syst. 24 556–64). The fabricated resonators have been tested in a temperature-controlled oven between  −20 °C and 60 °C, and the results of two distinct designs are compared to be able to observe the effectiveness of the strain amplifying beam. Measurement results show that the design with the strain amplifying beam increases the temperature coefficient of frequency of the resonators by 33 times when compared to the one-end free DETF resonators. Minimum detectable temperature variations observed by the resonators used in this study is 0.0011 °C. This kind of very high resolution temperature sensing can be achieved by integrating this MEMS temperature sensor with any type of physical MEMS sensor where its fabrication process includes different materials for the

  16. Design and fabrication of a high performance resonant MEMS temperature sensor

    Science.gov (United States)

    Kose, Talha; Azgin, Kivanc; Akin, Tayfun

    2016-04-01

    This paper presents a high performance MEMS temperature sensor comprised of a double-ended-tuning-fork (DETF) resonator and strain-amplifying beam structure. The temperature detection is based on the ‘thermal strain induced frequency variations’ of the DETF resonator. The major source of thermal strain leading to the frequency shifts is the difference in thermal expansion coefficients of the substrate and the device layers of the fabricated structures. By selecting the substrate as glass and the device layers as single crystal silicon, i.e. materials with different thermal expansion coefficients, the tines of the resonators are exposed to axial load with the changing temperature, which causes a change in the resonance frequency of the resonators. This resonance frequency shift can be related with the changing temperature by taking the thermal strain relations into consideration, which enables utilization of the resonator as a highly sensitive temperature sensor. The resonators used in this study have been fabricated by utilizing the advanced MEMS process that incorporates the simple silicon-on-glass process with the wafer level vacuum packaging Torunbalci et al (2015 J. Microelectromech. Syst. 24 556-64). The fabricated resonators have been tested in a temperature-controlled oven between  -20 °C and 60 °C, and the results of two distinct designs are compared to be able to observe the effectiveness of the strain amplifying beam. Measurement results show that the design with the strain amplifying beam increases the temperature coefficient of frequency of the resonators by 33 times when compared to the one-end free DETF resonators. Minimum detectable temperature variations observed by the resonators used in this study is 0.0011 °C. This kind of very high resolution temperature sensing can be achieved by integrating this MEMS temperature sensor with any type of physical MEMS sensor where its fabrication process includes different materials for the substrate

  17. A Study of Electromagnetic Transition of △(1232) Resonance

    Institute of Scientific and Technical Information of China (English)

    DONG Yu-Bing; LIU Jian

    2004-01-01

    Point form relativistic dynamics of relativistic quantum mechanics is employed to estimate the photon and electroproduction amplitudes of △(1232) resonance. Results are compared with the non-relativistic work, and the differences between the two frame works are discussed.

  18. Nonlinear resonance phenomena of a doped fibre laser under cavity-loss modulation: Experimental demonstrations

    Indian Academy of Sciences (India)

    A Ghosh; B K Goswami; R Vijaya

    2010-11-01

    Our experiments with an erbium-doped fibre ring laser (CW, single transverse mode and multiaxial mode) with an intracavity LiNbO3 electro-optic modulator (EOM) display the characteristic features of a nonlinear oscillator (e.g., harmonic and period-2 sub-harmonic resonances) when the EOM driver voltage is modulated periodically. Harmonic resonance leads to period-1 bistability and hysteresis. Inside the period-2 sub-harmonic resonance region, the laser exhibits Feigenbaum sequence and generalized bistability.

  19. Nuclear Tuning and Detuning of the Electron Spin Resonance in a Quantum Dot

    OpenAIRE

    Danon, Jeroen; Nazarov, Yuli V.

    2007-01-01

    We study nuclear spin dynamics in a quantum dot close to the conditions of electron spin resonance. We show that at small frequency mismatch the nuclear field detunes the resonance. Remarkably, at larger frequency mismatch its effect is opposite: The nuclear system is bistable, and in one of the stable states the field accurately tunes the electron spin splitting to resonance. In this state the nuclear field fluctuations are strongly suppressed and nuclear spin relaxation is accelerated.

  20. A COMPUTER-AIDED UNIFIED APPROACH TO MODELING PWM AND RESONANT CONVERTERS

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    This letter puts forward a method of modeling for the steady-state and small signal dynamic analysis on PWM, quasi-resonant and series/(parallel) resonant switching converters based on pulse-waveform integral approach. As an example, PWM and quasi-resonant converters are used to discuss the principle of the approach. The results are compared with those in the relative literatures. Computer aided analysis are made to confirm the correctness.

  1. Photon antibunching and bunching in a ring-resonator waveguide quantum electrodynamics system.

    Science.gov (United States)

    Chen, Zihao; Zhou, Yao; Shen, Jung-Tsung

    2016-07-15

    We numerically investigate the photonic state generation and its nonclassical correlations in a ring-resonator waveguide quantum electrodynamics system. Specifically, we discuss photon antibunching and bunching in various scenarios, including the imperfect resonator with backscattering and dissipations. Our numerical results indicate that an imperfect ring resonator with backscattering can enhance the quality of antibunching. In addition, we also identify the quantum photonic halo phenomenon in the photon scattering dynamics and the shoulder effect in the second-order correlation function.

  2. Photon antibunching and bunching in a ring-resonator waveguide quantum electrodynamics system.

    Science.gov (United States)

    Chen, Zihao; Zhou, Yao; Shen, Jung-Tsung

    2016-07-15

    We numerically investigate the photonic state generation and its nonclassical correlations in a ring-resonator waveguide quantum electrodynamics system. Specifically, we discuss photon antibunching and bunching in various scenarios, including the imperfect resonator with backscattering and dissipations. Our numerical results indicate that an imperfect ring resonator with backscattering can enhance the quality of antibunching. In addition, we also identify the quantum photonic halo phenomenon in the photon scattering dynamics and the shoulder effect in the second-order correlation function. PMID:27420523

  3. Optimum design of a polymer electro-optic microring resonator switch

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Novel transfer functions are presented for a polymer electro-optic microring resonator switches. The resonating process of the light in the microring is simulated using the formulas. Then the optimization of the structural parameters is performed,and the characteristics are analyzed, such as the resonance time, output spectrum, operation voltage, insertion loss and crosstalk were analyzed. The simulation results show that the designed device exhibits favorable switching functions.

  4. Non-Bragg Resonance of Standing Acoustic Wave in a Cylindrical Waveguide with Sinusoidally Perturbed Walls

    Institute of Scientific and Technical Information of China (English)

    TAO Zhi-Yong; XIAO Yu-Meng; WANG Xin-Long

    2005-01-01

    @@ A novel type of acoustic resonance different from the well-known Bragg resonance is predicted theoretically in an acoustic cylindrical waveguide with sinusoidally perturbed hard walls. The resonance is caused by the interaction between the standing acoustic waves, i.e. transverse modes in the waveguide. It results in the frequency spectrum splitting and the appearance of forbidden bands. For small-perturbed wall corrugation, it is found that the shifts of resonant frequencies and the width of the forbidden gap can be as small as the wall amplitude. The appearance of the non-Bragg resonance depends highly on the wall period. When the period is greater than 2.319 times the average cylinder radius, all the non-Bragg resonances cut off. The smaller the wall period, the greater the transverse mode involvement.

  5. A new z-axis resonant micro-accelerometer based on electrostatic stiffness.

    Science.gov (United States)

    Yang, Bo; Wang, Xingjun; Dai, Bo; Liu, Xiaojun

    2015-01-05

    Presented in the paper is the design, the simulation, the fabrication and the experiment of a new z-axis resonant accelerometer based on the electrostatic stiffness. The new z-axis resonant micro-accelerometer, which consists of a torsional accelerometer and two plane resonators, decouples the sensing movement of the accelerometer from the oscillation of the plane resonators by electrostatic stiffness, which will improve the performance. The new structure and the sensitive theory of the acceleration are illuminated, and the equation of the scale factor is deduced under ideal conditions firstly. The Ansys simulation is implemented to verify the basic principle of the torsional accelerometer and the plane resonator individually. The structure simulation results prove that the effective frequency of the torsional accelerometer and the plane resonator are 0.66 kHz and 13.3 kHz, respectively. Then, the new structure is fabricated by the standard three-mask deep dry silicon on glass (DDSOG) process and encapsulated by parallel seam welding. Finally, the detecting and control circuits are designed to achieve the closed-loop self-oscillation, to trace the natural frequency of resonator and to measure the system frequency. Experimental results show that the new z-axis resonant accelerometer has a scale factor of 31.65 Hz/g, a bias stability of 727 µg and a dynamic range of over 10 g, which proves that the new z-axis resonant micro-accelerometer is practicable.

  6. A New Z-axis Resonant Micro-Accelerometer Based on Electrostatic Stiffness

    Directory of Open Access Journals (Sweden)

    Bo Yang

    2015-01-01

    Full Text Available Presented in the paper is the design, the simulation, the fabrication and the experiment of a new z-axis resonant accelerometer based on the electrostatic stiffness. The new z-axis resonant micro-accelerometer, which consists of a torsional accelerometer and two plane resonators, decouples the sensing movement of the accelerometer from the oscillation of the plane resonators by electrostatic stiffness, which will improve the performance. The new structure and the sensitive theory of the acceleration are illuminated, and the equation of the scale factor is deduced under ideal conditions firstly. The Ansys simulation is implemented to verify the basic principle of the torsional accelerometer and the plane resonator individually. The structure simulation results prove that the effective frequency of the torsional accelerometer and the plane resonator are 0.66 kHz and 13.3 kHz, respectively. Then, the new structure is fabricated by the standard three-mask deep dry silicon on glass (DDSOG process and encapsulated by parallel seam welding. Finally, the detecting and control circuits are designed to achieve the closed-loop self-oscillation, to trace the natural frequency of resonator and to measure the system frequency. Experimental results show that the new z-axis resonant accelerometer has a scale factor of 31.65 Hz/g, a bias stability of 727 µg and a dynamic range of over 10 g, which proves that the new z-axis resonant micro-accelerometer is practicable.

  7. Sweeping a molecular Bose-Einstein condensate across a Feshbach resonance

    OpenAIRE

    Haque, M.; Stoof, H. T. C.

    2007-01-01

    We consider the dissociation of a molecular Bose-Einstein condensate during a magnetic-field sweep through a Feshbach resonance that starts on the molecular side of the resonance and ends on the atomic side. In particular, we determine the energy distribution of the atoms produced after the sweep. We find that the shape of the energy distribution strongly depends on the rate of the magnetic-field sweep, in a manner that is in good agreement with recent experiments.

  8. A thickness-shear MEMS resonator employing electromechanical transduction through a coplanar waveguide

    OpenAIRE

    Johnson, W. L.; Wallis, T.M.; Kabos, P.; Rocas Cantenys, Eduard; Collado Gómez, Juan Carlos; Liew, L.A.; Ha, J.Y.; Davydov, A. V.; Plankis, A.; Heyliger, P.R.

    2012-01-01

    The design, modeling, fabrication, and characterization of a vibrationally trapped thickness-shear MEMS resonator is presented. This device is intended to avoid various limitations of flexural MEMS resonators, including nonlinearity, clamping losses, thermoelastic damping, and high damping in liquid. It includes a silicon bridge and a reference line on an SOI wafer, a coupled Au/Cr coplanar waveguide, Lorentz-force coupling, variations in waveguide thickness for vibration...

  9. Numerical simulation of a short RFQ resonator using the MAFIA codes

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H.; Ben-Zvi, I.; Jain, A.; Paul, P. (State Univ. of New York, Stony Brook, NY (United States). Dept. of Physics); Lombardi, A. (Istituto Nazionale di Fisica Nucleare, Legnaro (Italy). Lab. Nazionale di Legnaro)

    1991-01-01

    The electrical characteristics of a short (2{beta}{lambda}=0.4 m) resonator with large modulation (m=4) have been studied using the three dimensional codes, MAFIA. The complete resonator, including the modulated electrodes and a complex support structure, has been simulated using {approximately} 350,000 mesh points. Important characteristics studied include the resonant frequency, electric and magnetic fields distributions, quality factor and stored energy. The results of the numerical simulations are compared with the measurements of an actual resonator and analytical approximations. 7 refs., 3 figs., 1 tab.

  10. Baryon resonances in the mean field approach and a simple explanation of the Theta+ pentaquark

    CERN Document Server

    Diakonov, Dmitri

    2008-01-01

    We suggest to classify baryon resonances as single-quark states in a mean field, and/or as its collective excitations. Identifying the Roper resonance N(1440), the nucleon resonance N(1535), and the singlet hyperon Lambda(1405) as single-quark excitations, we find that there must be an exotic S=+1 baryon resonance Theta+ (the "pentaquark") with a mass about 1440+1535-1405=1570 MeV and spin-parity one-half-plus. We argue that Theta+ is an analog of the Gamov--Teller excitation long known in nuclear physics.

  11. Magnetic resonance imaging in entomology: a critical review

    OpenAIRE

    Hart, A.G.; Bowtell, R W; Köckenberger, W; Wenseleers, T.; Ratnieks, F.L.W.

    2005-01-01

    Magnetic resonance imaging (MRI) enables in vivo imaging of organisms. The recent development of the magnetic resonance microscope (MRM) has enabled organisms within the size range of many insects to be imaged. Here, we introduce the principles of MRI and MRM and review their use in entomology. We show that MRM has been successfully applied in studies of parasitology, development, metabolism, biomagnetism and morphology, and the advantages and disadvantages relative to other imaging technique...

  12. Parametrics Resonances of a Forced Modified Rayleigh-Duffing Oscillator

    CERN Document Server

    Miwadinou, C H; Chabi, J B

    2013-01-01

    We investigate in this paper the superharmonic and subharmonic resonances of forced modified Rayleigh-Duffing oscillator. We analyse this equation by method of multiple scales and we obtain superharmonic and subharmonic resonances order-two and order-three. We obtain also regions where steady-state subharmonic responses exist. Finally, we use the amplitude-frequency curve for demonstrate the effect of various parameters on the response of the system.

  13. Suppression of bending waves in a beam using resonators with different separation lengths.

    Science.gov (United States)

    Yang, Cheng; Cheng, Li

    2016-05-01

    This work is concerned with the suppression of a bending wave in a beam using resonators. Particular focus is put on the separation length between resonators. It is demonstrated that, for a beam with identical resonators attached at equal intervals, the bending wave transmission efficiency varies with respect to the separation length. The phenomena and the underlying physics are investigated by resorting to a simple beam model having two resonators resting on it. The two resonators are coupled over the segment through various bending wave components, comprising both propagating waves and evanescent waves, generated at the resonator locations where the beam encounters impedance discontinuities. The separation length, specifying the phase change of the propagating waves and the amplitude decay of the evanescent waves travelling from one resonator to the other, is thereby the parameter determining the extent to which the resonators would be coupled and the degree of the power that is transmitted. Results show, qualitatively, the difference in the working mechanism of the resonators in different separation length regions, with criteria being defined to distinguish those regions. Particularly, in the intermediate separation region, the evanescent waves are shown to play an important role in the coupling and are responsible for transmitting power, comparable with that transmitted by propagating waves, to the far field. PMID:27250132

  14. Broadband performance of a piezoelectric energy harvester based on the internal resonance of buckled beam

    Science.gov (United States)

    Xiong, Liuyang; Tang, Lihua; Ding, Hu; Chen, Liqun; Mace, Brian

    2016-04-01

    Nonlinear internal resonance mechanism is exploited in piezoelectric vibration energy harvesting (PVEH) for the purpose of broadening the resonance band. Conventional linear energy harvester has narrow operating bandwidth. In this research, a buckled piezoelectric beam structure with preload under transverse excitation is investigated to demonstrate the superiority of internal resonance. The condition for 2:1 internal resonance could be established by truncating the continuum beam with geometrical nonlinearity. Integro-partial-differential equations are derived for governing transverse motion measured from a stable equilibrium position. At specific initial axial compressive force, two modes are coupled through the internal resonance interaction. For weak nonlinear perturbations, multiple scales method is used to explore the amplitude-frequency responses of the buckled beam system under primary resonance with 2:1 internal resonance. Numerical examples demonstrate that the resonance bandwidth is broadened thanks to the coexistence of softening and hardening nonlinear characteristics. Moreover, validity of the approximate analytical method is demonstrated by comparing with simulation. Furthermore, the optimal resistance is discussed with a pure resistive load. This research on the internal resonance of buckled beam provides a basis for structure design and optimization in broadband PVEH.

  15. A Magnetic Resonance (MR) Microscopy System using a Microfluidically Cryo-Cooled Planar Coil

    OpenAIRE

    Koo, Chiwan; Godley, Richard F.; Park, Jaewon; McDougall, Mary P.; Wright, Steven M; Han, Arum

    2011-01-01

    We present the development of a microfluidically cryo-cooled planar coil for magnetic resonance (MR) microscopy. Cryogenically cooling radiofrequency (RF) coils for magnetic resonance imaging (MRI) can improve the signal to noise ratio (SNR) of the experiment. Conventional cryostats typically use a vacuum gap to keep samples to be imaged, especially biological samples, at or near room temperature during cryo-cooling. This limits how close a cryo-cooled coil can be placed to the sample. At the...

  16. Voltage Generation by Ferromagnetic Resonance at a Nonmagnet to Ferromagnet Contact

    NARCIS (Netherlands)

    Wang, X.; Bauer, G.E.W.; Van Wees, B.J.; Brataas, A.; Tserkovnyak, Y.

    2006-01-01

    A ferromagnet can resonantly absorb rf radiation to sustain a steady precession of the magnetization around an internal or applied magnetic field. We show that, under these ferromagnetic resonance conditions, a dc voltage is generated at a normal-metal electric contact to a ferromagnet with spin-fli

  17. Harmonic Resonances in Metal Rods--Easy Experimentation with a Smartphone and Tablet PC

    Science.gov (United States)

    Hirth, Michael; Gröber, Sebastian; Kuhn, Jochen; Müller, Andreas

    2016-01-01

    A variety of experiments with smartphones and tablet PCs allow a precise analysis of acoustic phenomena. For example, we recently described an experiment in which a noise signal simultaneously triggered harmonic acoustic resonances in the air column of a tube open at both ends and a tube closed at one end. The measured resonant frequencies were…

  18. Design and fabrication of a 20 MHz pn-diode silicon ring resonator with in-plane vibration mode

    Science.gov (United States)

    Asahi, Yoichi; Tanigawa, Hiroshi; Nishino, Tomoki; Furutsuka, Takashi; Suzuki, Kenichiro

    2016-06-01

    In this paper, we report a new microelectromechanical system (MEMS) resonator based on the pn-diode principle. The pn-diode-based resonator can eliminate the narrow gap that conventional electrostatic MEMS resonators need between driving electrodes. This is expected to solve several serious problems related to fabrication, packaging, and lifetime. However, the resonators previously reported had pn-diodes formed in the vertical direction. Because the resonant frequency is determined by the thickness of the resonator plate, the resonant frequency in formed resonators cannot be changed in the same chip. To solve this problem, we newly design a pn-diode resonator with a lateral vibration. Because the resonant frequency is determined by plate width, this new resonator can provide various resonators with different frequencies in a chip, which is most suitable for the integration of MEMS resonators with electronic circuits. Our research objective at present is related to design and fabrication. By using a simulator, we design a ring resonator of 20 MHz. In the fabrication, we develop a technique of using ion implantation to form a 3-µm-thick pn-diode. The results shown here are very useful for improving the MEMS resonators.

  19. Use of a helical resonator as a capacitive transducer in vibrating reed measurements

    Science.gov (United States)

    Xiang, X.-D.; Brill, J. W.; Fuqua, W. L.

    1989-09-01

    A new design of vibrating reed apparatus for studying high-resonant overtones of very small samples is described. Using the high Q (about 1000) helical RF resonator as a capacitive transducer, great sensitivity has been obtained. The theoretical sensitivity of the detector is investigated with transmission-line theory, and the result shows that the Johnson-noise-limited sensitivity is proportional to the Q of the resonator instead of Q exp 1/2, as is the case of lumped LC-tuned circuit analyses. For a nonsuperconducting resonator, the Johnson-noise-limited minimum detectable displacement at room temperature, with bandwidth B, is about 10 to the -7th A sq rt B/Hz, if the RF electrical field level is only limited by vacuum breakdown. An application of the apparatus in studying the temperature-dependent changes in the Young's modulus of single crystals of TaS3 is shown.

  20. A Model of Resonance Scattering on Curved Quantum Wires

    Science.gov (United States)

    Exner, Pavel

    A model of electron motion in a curved quantum wire of a finite length 2D attached to a pair of macroscopic electrodes is studied. Regarding the problem as a two-dimensional one, we model the electrodes as halfplanes and the quantum wire as a line segment joining them; it supports a potential which is a combination of a constant transversal-mode energy and an attractive curvature-induced term. We show that the bound states which may be present at an infinite quantum wire turn into resonances and that spectral concentration is valid as D .Translated AbstractEin Modell der Resonanzstreuung auf gekrümmten, dünnen DrähtenDas Modell einer Elektronenbewegung in einem gekrümmten, ultradünnen Draht der Länge 2D, der zwei makroskopische Elektroden verbindet, wird untersucht. Das Modell als zweidimensional betrachtend, nehmen wir die Elektroden als Halbebenen und den Draht als verbindendes Liniensegment. Das Potential ist eine Kombination aus konstanter Transversalmoden-energie und einem anziehenden, von der Krümmung hervorgerufenen Term. Wir zeigen, daß der gebundene Zustand, der im unendlich langen Draht auftreten kann, in Resonanzen übergeht, und die Spektraldichte für D gilt.

  1. Surface plasmon resonance microscopy: Achieving a quantitative optical response

    Science.gov (United States)

    Peterson, Alexander W.; Halter, Michael; Plant, Anne L.; Elliott, John T.

    2016-09-01

    Surface plasmon resonance (SPR) imaging allows real-time label-free imaging based on index of refraction and changes in index of refraction at an interface. Optical parameter analysis is achieved by application of the Fresnel model to SPR data typically taken by an instrument in a prism based figuration. We carry out SPR imaging on a microscope by launching light into a sample and collecting reflected light through a high numerical aperture microscope objective. The SPR microscope enables spatial resolution that approaches the diffraction limit and has a dynamic range that allows detection of subnanometer to submicrometer changes in thickness of biological material at a surface. However, unambiguous quantitative interpretation of SPR changes using the microscope system could not be achieved using the Fresnel model because of polarization dependent attenuation and optical aberration that occurs in the high numerical aperture objective. To overcome this problem, we demonstrate a model to correct for polarization diattenuation and optical aberrations in the SPR data and develop a procedure to calibrate reflectivity to index of refraction values. The calibration and correction strategy for quantitative analysis was validated by comparing the known indices of refraction of bulk materials with corrected SPR data interpreted with the Fresnel model. Subsequently, we applied our SPR microscopy method to evaluate the index of refraction for a series of polymer microspheres in aqueous media and validated the quality of the measurement with quantitative phase microscopy.

  2. Hybrid circuit cavity quantum electrodynamics with a micromechanical resonator.

    Science.gov (United States)

    Pirkkalainen, J-M; Cho, S U; Li, Jian; Paraoanu, G S; Hakonen, P J; Sillanpää, M A

    2013-02-14

    Hybrid quantum systems with inherently distinct degrees of freedom have a key role in many physical phenomena. Well-known examples include cavity quantum electrodynamics, trapped ions, and electrons and phonons in the solid state. In those systems, strong coupling makes the constituents lose their individual character and form dressed states, which represent a collective form of dynamics. As well as having fundamental importance, hybrid systems also have practical applications, notably in the emerging field of quantum information control. A promising approach is to combine long-lived atomic states with the accessible electrical degrees of freedom in superconducting cavities and quantum bits (qubits). Here we integrate circuit cavity quantum electrodynamics with phonons. Apart from coupling to a microwave cavity, our superconducting transmon qubit, consisting of tunnel junctions and a capacitor, interacts with a phonon mode in a micromechanical resonator, and thus acts like an atom coupled to two different cavities. We measure the phonon Stark shift, as well as the splitting of the qubit spectral line into motional sidebands, which feature transitions between the dressed electromechanical states. In the time domain, we observe coherent conversion of qubit excitation to phonons as sideband Rabi oscillations. This is a model system with potential for a quantum interface, which may allow for storage of quantum information in long-lived phonon states, coupling to optical photons or for investigations of strongly coupled quantum systems near the classical limit.

  3. Coupling of a locally implanted rare-earth ion ensemble to a superconducting micro-resonator

    Energy Technology Data Exchange (ETDEWEB)

    Wisby, I., E-mail: ilana.wisby@npl.co.uk; Tzalenchuk, A. Ya. [National Physical Laboratory, Hampton Road, Teddington TW11 0LW (United Kingdom); Royal Holloway, University of London, Egham TW20 0EX (United Kingdom); Graaf, S. E. de; Adamyan, A.; Kubatkin, S. E. [Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, SE-41296, Gothenburg (Sweden); Gwilliam, R. [Advanced Technology Institute, Faculty of Electronics and Physical Sciences, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Meeson, P. J. [Royal Holloway, University of London, Egham TW20 0EX (United Kingdom); Lindström, T. [National Physical Laboratory, Hampton Road, Teddington TW11 0LW (United Kingdom)

    2014-09-08

    We demonstrate the coupling of rare-earth ions locally implanted in a substrate (Gd{sup 3+} in Al{sub 2}O{sub 3}) to a superconducting NbN lumped-element micro-resonator. The hybrid device is fabricated by a controlled ion implantation of rare-earth ions in well-defined micron-sized areas, aligned to lithographically defined micro-resonators. The technique does not degrade the internal quality factor of the resonators which remain above 10{sup 5}. Using microwave absorption spectroscopy, we observe electron-spin resonances in good agreement with numerical modelling and extract corresponding coupling rates of the order of 1 MHz and spin linewidths of 50–65 MHz.

  4. Steady-state entanglement of a Bose-Einstein condensate and a nanomechanical resonator

    CERN Document Server

    Asjad, Muhammad; 10.1103/PhysRevA.84.033606

    2011-01-01

    We analyze the steady-state entanglement between Bose-Einstein condensate trapped inside an optical cavity with a moving end mirror (nanomechanical resonator) driven by a single mode laser. The quantized laser field mediates the interaction between the Bose-Einstein condensate and nanomechanical resonator. In particular, we study the influence of temperature on the entanglement of the coupled system, and note that the steady-state entanglement is fragile with respect to temperature.

  5. The efficiency of resonant relaxation around a massive black hole

    CERN Document Server

    Eilon, Ehud; Alexander, Tal

    2008-01-01

    Resonant relaxation (RR) is a rapid relaxation process that operates in the nearly-Keplerian potential near a massive black hole (MBH). RR dominates the dynamics of compact remnants that inspiral into a MBH and emit gravitational waves (extreme mass ratio inspiral events, EMRIs). RR can either increase the EMRI rate, or strongly suppress it, depending on its still poorly-determined efficiency. We use small-scale Newtonian N-body simulations to measure the RR efficiency and to explore its possible dependence on the stellar number density profile around the MBH, and the mass-ratio between the MBH and a star (a single-mass stellar population is assumed). We develop an efficient and robust procedure for detecting and measuring RR in N-body simulations. We present a suite of simulations with a range of stellar density profiles and mass-ratios, and measure the mean RR efficiency in the near-Keplerian limit. We do not find a statistically significant dependence on the density profile or the mass-ratio. Our numerical...

  6. Fluctuations, Response, and Resonances in a Simple Atmospheric Model

    CERN Document Server

    Gritsun, Andrey

    2016-01-01

    We study the response of a simple quasi-geostrophic barotropic model of the atmosphere to various classes of perturbations affecting its forcing and its dissipation using the formalism of the Ruelle response theory. We investigate the geometry of such perturbations using the covariant Lyapunov vectors on the unperturbed system and discover in one specific case - orographic forcing - a substantial projection of the perturbation onto the stable directions of the flow. As a result, we find a clear violation of the fluctuation-dissipation theorem, in agreement with the basic tenets of nonequilibrium statistical mechanics. This results into a very strong response in the form of a forced Rossby-like wave that has no resemblance to the natural variability in the same range of spatial and temporal scales. We further analyze such a feature and discover it can be interpreted as resonant response to a specific group of rarely visited unstable periodic orbits of the unperturbed system. Our results reinforce the idea of u...

  7. Baryon resonances in a chiral confining model, 1

    CERN Document Server

    Umino, Y

    1998-01-01

    In this two part series a chiral confining model of baryons is used to describe low--lying negative parity resonances $N^*$, $\\Delta^*$, $\\Lambda^*$ and $\\Sigma^*$ in the mean field approximation. A physical baryon in this model consists of interacting valence quarks, mesons and a color and chiral singlet hybrid field coexisting inside a dynamically generated confining region. This first paper presents the quark contribution to the masses and wave functions of negative parity baryons calculated with an effective spin--isospin dependent instanton induced interaction. It does not include meson exchanges between quarks. The three--quark wave functions are used to calculate meson--excited baryon vertex functions to lowest order in meson--quark coupling. When the baryons are on mass--shell each of these vertex functions is a product of a coupling constant and a form factor. As examples, quark contributions to $N^*$ hadronic form factors as well as axial coupling constants are extracted from the vertex functions an...

  8. Nondestructive relative permittivity and loss tangent measurements using a split-cylinder resonator

    Science.gov (United States)

    Janezic, Michael Daniel

    To keep pace with the expanding wireless and electronics industries, manufacturers are developing innovative materials for improving system performance, and there is a critical need to accurately characterize the electrical properties of these new materials at microwave frequencies. To address this need, this thesis develops a nondestructive method for measuring the relative permittivity and loss tangent of dielectric substrates using a split-cylinder resonator. Three theoretical models for the split-cylinder resonator are derived using mode-matching, least-squares boundary residual, and Hankel-transform methods, from which one can calculate the relative permittivity and loss tangent of a dielectric substrate from measurements of the split-cylinder resonator's TE0np resonant frequency and quality factor. Each of these models has several advantages over previously published models. First, the accuracy of the relative permittivity measurement is increased because each model accurately models the fringing fields that extend beyond the cylindrical-cavity sections. Second, to increase the accuracy of the loss tangent measurement, each model accurately separates the conductive metal losses of the split-cylinder resonator from the dielectric losses of the substrate. Finally, in contrast to previous models for the split-cylinder resonator that use only the TE011 resonant mode, each of the new models include the higher-order TE0np resonant modes, thereby broadening the frequency range over which one can make relative permittivity and loss tangent measurements. In a comparison of the three models, the mode-matching method was found to be superior on the basis of measurement accuracy and computational speed. Relative permittivity and loss tangent measurements for several dielectric materials are performed using a split-cylinder resonator and are in good agreement with measurements made using a circular-cylindrical cavity, split-post resonator, and dielectric post resonator

  9. Generalization of a 3-D Acoustic Resonator Model for the Simulation of Spherical Enclosures

    Directory of Open Access Journals (Sweden)

    Dutilleux Pierre

    2001-01-01

    Full Text Available A rectangular enclosure has such an even distribution of resonances that it can be accurately and efficiently modelled using a feedback delay network. Conversely, a nonrectangular shape such as a sphere has a distribution of resonances that challenges the construction of an efficient model. This work proposes an extension of the already known feedback delay network structure to model the resonant properties of a sphere. A specific frequency distribution of resonances can be approximated, up to a certain frequency, by inserting an allpass filter of moderate order after each delay line of a feedback delay network. The structure used for rectangular boxes is therefore augmented with a set of allpass filters allowing parametric control over the enclosure size and the boundary properties. This work was motivated by informal listening tests which have shown that it is possible to identify a basic shape just from the distribution of its audible resonances.

  10. Room temperature, very sensitive thermometer using a doubly clamped microelectromechanical beam resonator for bolometer applications

    Science.gov (United States)

    Zhang, Y.; Watanabe, Y.; Hosono, S.; Nagai, N.; Hirakawa, K.

    2016-04-01

    We propose a room temperature, all electrical driving and detecting, very sensitive thermometer structure using a microelectromechanical (MEMS) resonator for bolometer applications. We have fabricated a GaAs doubly clamped MEMS beam resonator whose oscillation can be excited and detected by the piezoelectric effect. When a heating power is applied to a NiCr film deposited on the MEMS beam surface, internal thermal stress is generated in the beam, leading to a reduction in the resonance frequency. The present device detects the shift in the resonance frequency caused by heating and works as a very sensitive thermometer. When the resonator was driven by a voltage slightly below the threshold for the nonlinear, hysteretic oscillation, the thermometer showed a voltage responsivity of about 3300 V/W, while keeping a low noise spectral density of about 60 nV/Hz1/2, demonstrating a noise equivalent power of bolometers for room-temperature operation.

  11. Harmonic control: A natural way to bridge resonant control and repetitive control

    DEFF Research Database (Denmark)

    Zhou, Keliang; Lu, Wenzhou; Yang, Yongheng;

    2013-01-01

    much fast convergence rate at these frequencies. It makes a good trade-off between resonant control and repetitive control: a parallel combination of multiple resonant controllers can track/eliminate selective harmonic frequencies very fast, but cause heavy parallel computation; a repetitive controller...

  12. A Micromachined Pressure Sensor with Integrated Resonator Operating at Atmospheric Pressure

    Directory of Open Access Journals (Sweden)

    Sen Ren

    2013-12-01

    Full Text Available A novel resonant pressure sensor with an improved micromechanical double-ended tuning fork resonator packaged in dry air at atmospheric pressure is presented. The resonator is electrostatically driven and capacitively detected, and the sensor is designed to realize a low cost resonant pressure sensor with medium accuracy. Various damping mechanisms in a resonator that is vibrating at atmospheric pressure are analyzed in detail, and a formula is developed to predict the overall quality factor. A trade-off has been reached between the quality factor, stress sensitivity and drive capability of the resonator. Furthermore, differential sense elements and the method of electromechanical amplitude modulation are used for capacitive detection to obtain a large signal-to-noise ratio. The prototype sensor chip is successfully fabricated using a micromachining process based on a commercially available silicon-on-insulator wafer and is hermetically encapsulated in a custom 16-pin Kovar package. Preliminary measurements show that the fundamental frequency of the resonant pressure sensor is approximately 34.55 kHz with a pressure sensitivity of 20.77 Hz/kPa. Over the full scale pressure range of 100–400 kPa and the whole temperature range of −20–60 °C, high quality factors from 1,146 to 1,772 are obtained. The characterization of the prototype sensor reveals the feasibility of a resonant pressure sensor packaged at atmospheric pressure.

  13. Stellar Dynamics around a Massive Black Hole II: Resonant Relaxation

    CERN Document Server

    Sridhar, S

    2015-01-01

    We present a first-principles theory of Resonant Relaxation (RR) of stellar systems orbiting within the sphere of influence of massive black holes in galactic nuclei. We extend the rigorous kinetic theory of Gilbert (1968) to include the Keplerian field of a black hole of mass $M_\\bullet$, and specialize to a (Keplerian) stellar system of mass $M \\ll M_\\bullet$. Using the results of the secular collisionless theory of Paper I, we orbit-average the kinetic equation through perturbative development in the small parameter $\\varepsilon = M/M_\\bullet$. This is supplemented with contributions from general relativistic corrections up to 1.5 post-Newtonian order and external gravitational sources. The result is a kinetic equation for a secular distribution function (DF) in 5-dim (Gaussian Ring) space, with explicit forms for the fluctuation and dissipation components of the collision integral. For general DFs, both apsidal and nodal precessions contribute to RR; so the traditional, physically-motivated distinction be...

  14. A new electron paramagnetic resonance method to identify irradiated soybean.

    Science.gov (United States)

    Sanyal, Bhaskar; Sharma, Arun

    2009-10-01

    Low-dose gamma irradiation causes minimal changes in food matrix making identification of radiation-processed foods a challenging task. In the present study, soybean samples were irradiated with commercially permitted gamma radiation dose in the 0.25 to 1.0 kGy range for insect disinfestations of food. Immediately after irradiation electron paramagnetic resonance (EPR) spectrum of the skin part of soybean showed a triplet signal (g = 2.0046, hyperfine coupling constant hfcc = 3.0 mT) superimposed on naturally present singlet. These signals were characterized as cellulose and phenoxyl radicals using EPR spectrum simulation technique. Kernel part of the samples exhibited a short-lived, radiation-induced singlet of carbon-centered radical superimposed on naturally present sextet signal of Mn2+. A detailed study on relaxation and thermal behavior of induced radicals in skin part was carried out using EPR spectroscopy. These findings revealed that progressive saturation and thermal characteristics of the induced radicals may be the most suitable parameters to distinguish soybean subjected to radiation dose as low as 0.25 kGy from thermally treated and nonirradiated samples, even after a prolonged period of storage.

  15. Ferromagnetic Resonance of a Single Magnetochiral Metamolecule of Permalloy

    Science.gov (United States)

    Kodama, Toshiyuki; Tomita, Satoshi; Kato, Takeshi; Oshima, Daiki; Iwata, Satoshi; Okamoto, Satoshi; Kikuchi, Nobuaki; Kitakami, Osamu; Hosoito, Nobuyoshi; Yanagi, Hisao

    2016-08-01

    We investigate the ferromagnetic resonance (FMR) of a single chiral structure of a ferromagnetic metal—the magnetochiral (MCh) metamolecule. Using a strain-driven self-coiling technique, micrometer-sized MCh metamolecules of metallic permalloy (Py) are fabricated without any residual Py films. The magnetization curves of ten Py MCh metamolecules obtained by an alternating gradient magnetometer show soft magnetic behavior. In cavity FMR with a magnetic-field sweep and coplanar-waveguide (CPW) FMR with a frequency sweep, the Kittel-mode FMR of the single Py metamolecule is observed. The CPW-FMR results, which are consistent with the cavity-FMR results, bring about the effective g factor, effective magnetization, and Gilbert damping of the single metamolecule. Together with calculations using these parameters, the angle-resolved cavity FMR reveals that the magnetization in the Py MCh metamolecule is most likely to be the hollow-bar type of configuration when the external magnetic field is applied parallel to the chiral axis, although the expected magnetization state at remanence is the corkscrew type of configuration.

  16. A haptic unit designed for magnetic-resonance-guided biopsy.

    Science.gov (United States)

    Tse, Z T H; Elhawary, H; Rea, M; Young, I; Davis, B L; Lamperth, M

    2009-02-01

    The magnetic fields present in the magnetic resonance (MR) environment impose severe constraints on any mechatronic device present in its midst, requiring alternative actuators, sensors, and materials to those conventionally used in traditional system engineering. In addition the spatial constraints of closed-bore scanners require a physical separation between the radiologist and the imaged region of the patient. This configuration produces a loss of the sense of touch from the target anatomy for the clinician, which often provides useful information. To recover the force feedback from the tissue, an MR-compatible haptic unit, designed to be integrated with a five-degrees-of-freedom mechatronic system for MR-guided prostate biopsy, has been developed which incorporates position control and force feedback to the operator. The haptic unit is designed to be located inside the scanner isocentre with the master console in the control room. MR compatibility of the device has been demonstrated, showing a negligible degradation of the signal-to-noise ratio and virtually no geometric distortion. By combining information from the position encoder and force sensor, tissue stiffness measurement along the needle trajectory is demonstrated in a lamb liver to aid diagnosis of suspected cancerous tissue. PMID:19278193

  17. A new Skyrme energy density functional for a better description of spin-isospin resonances

    Science.gov (United States)

    Roca-Maza, X.; Colò, G.; Cao, Li-Gang; Sagawa, H.

    2015-10-01

    A correct determination of the isospin and spin-isospin properties of the nuclear effective interaction should lead to an accurate description of the Gamow-Teller resonance (GT), the Spin Dipole Resonance (SDR), the Giant Dipole Resonance (GDR) or the Antianalog Giant Dipole Resonance (AGDR), among others. A new Skyrme energy density functional named SAMi is introduced with the aim of going a step forward in setting the bases for a more precise description of spin-isospin resonances [1, 2]. In addition, we will discuss some new features of our analysis on the AGDR in 208Pb [3] as compared with available experimental data on this resonance [4, 5, 6], and on the GDR [7]. Such study, guided by a simple yet physical pocket formula, has been developed by employing the so called SAMi-J family of systematically varied interactions. This set of interactions is compatible with experimental data for values of the symmetry energy at saturation J and slope parameter L falling in the ranges 31-33 MeV and 75-95 MeV, respectively.

  18. A new Skyrme energy density functional for a better description of spin-isospin resonances

    Energy Technology Data Exchange (ETDEWEB)

    Roca-Maza, X., E-mail: xavier.roca.maza@mi.infn.it [Dipartimento di Fisica, Università degli Studi di Milano, via Celoria 16, 20133 Milano (Italy); Istituto Nazionale di Fisica Nucleare (INFN), Sez. di Milano, via Celoria 16, 20133 Milano (Italy); Colò, G. [Dipartimento di Fisica, Università degli Studi di Milano, via Celoria 16, 20133 Milano (Italy); Istituto Nazionale di Fisica Nucleare (INFN), Sez. di Milano, via Celoria 16, 20133 Milano (Italy); Kavli Institute for Theoretical Physics China, CAS, Beijing 100190 (China); Cao, Li-Gang [Kavli Institute for Theoretical Physics China, CAS, Beijing 100190 (China); School of Mathematics and Physics, North China Electric Power University, Beijing 102206 (China); State Key Laboratory of Theoretical Physics, ITP, Chinese Academy of Sciences, Beijing 100190 (China); National Laboratory of Heavy Ion Accelerator of Lanzhou, Lanzhou 730000 (China); Sagawa, H. [Kavli Institute for Theoretical Physics China, CAS, Beijing 100190 (China); Center for Mathematics and Physics, University of Aizu, Aizu-Wakamatsu, Fukushima 965-8580 (Japan); RIKEN, Nishina Center, Wako, 351-0198 (Japan)

    2015-10-15

    A correct determination of the isospin and spin-isospin properties of the nuclear effective interaction should lead to an accurate description of the Gamow-Teller resonance (GT), the Spin Dipole Resonance (SDR), the Giant Dipole Resonance (GDR) or the Antianalog Giant Dipole Resonance (AGDR), among others. A new Skyrme energy density functional named SAMi is introduced with the aim of going a step forward in setting the bases for a more precise description of spin-isospin resonances [1, 2]. In addition, we will discuss some new features of our analysis on the AGDR in {sup 208}Pb [3] as compared with available experimental data on this resonance [4, 5, 6], and on the GDR [7]. Such study, guided by a simple yet physical pocket formula, has been developed by employing the so called SAMi-J family of systematically varied interactions. This set of interactions is compatible with experimental data for values of the symmetry energy at saturation J and slope parameter L falling in the ranges 31−33 MeV and 75−95 MeV, respectively.

  19. A new Skyrme energy density functional for a better description of spin-isospin resonances

    International Nuclear Information System (INIS)

    A correct determination of the isospin and spin-isospin properties of the nuclear effective interaction should lead to an accurate description of the Gamow-Teller resonance (GT), the Spin Dipole Resonance (SDR), the Giant Dipole Resonance (GDR) or the Antianalog Giant Dipole Resonance (AGDR), among others. A new Skyrme energy density functional named SAMi is introduced with the aim of going a step forward in setting the bases for a more precise description of spin-isospin resonances [1, 2]. In addition, we will discuss some new features of our analysis on the AGDR in 208Pb [3] as compared with available experimental data on this resonance [4, 5, 6], and on the GDR [7]. Such study, guided by a simple yet physical pocket formula, has been developed by employing the so called SAMi-J family of systematically varied interactions. This set of interactions is compatible with experimental data for values of the symmetry energy at saturation J and slope parameter L falling in the ranges 31−33 MeV and 75−95 MeV, respectively

  20. Tilted resonators in a triangular elastic lattice: chirality, Bloch waves and negative refraction

    CERN Document Server

    Tallarico, Domenico; Movchan, Alexander B; Colquitt, Daniel J

    2016-01-01

    We consider a vibrating triangular mass-truss lattice whose unit cell contains a resonator of a triangular shape. The resonators are connected to the triangular lattice by trusses. Each resonator is tilted, i.e. it is rotated with respect to the triangular lattice's unit cell through an angle $\\vartheta_0$. This geometrical parameter is responsible for the emergence of a resonant mode in the Bloch spectrum for elastic waves and strongly affects the dispersive properties of the lattice. Additionally, the tilting angle $\\vartheta_0$ triggers the opening of a band gap at a Dirac-like point. We provide a physical interpretation of these phenomena and discuss the dynamical implications on elastic Bloch waves. The dispersion properties are used to design a structured interface containing tilted resonators which exhibit negative refraction and focussing, as in a "flat elastic lens".