WorldWideScience

Sample records for range resonant energy

  1. Performance analysis and experimental verification of mid-range wireless energy transfer through non-resonant magnetic coupling

    DEFF Research Database (Denmark)

    Peng, Liang; Wang, Jingyu; Zhejiang University, Hangzhou, China, L.

    2011-01-01

    In this paper, the efficiency analysis of a mid-range wireless energy transfer system is performed through non-resonant magnetic coupling. It is shown that the self-resistance of the coils and the mutual inductance are critical in achieving a high efficiency, which is indicated by our theoretical...... formulation and verified in our experiments. It is experimentally shown that high efficiency, up to 65%, can be realized even in a non-resonant wireless energy system which employs a device part with moderate or low quality factor. We also address some aspects of a practical wireless energy transfer system...... and show that careful design of the de-tuned system can intrinsically minimize the power dissipated in the source part. Our non-resonant scheme presented in this paper allows flexible design and fabrication of a wireless energy transfer systems with transfer distance being several times of the coils...

  2. Paper-based solid-phase multiplexed nucleic acid hybridization assay with tunable dynamic range using immobilized quantum dots as donors in fluorescence resonance energy transfer.

    Science.gov (United States)

    Noor, M Omair; Krull, Ulrich J

    2013-08-06

    A multiplexed solid-phase nucleic acid hybridization assay on a paper-based platform is presented using multicolor immobilized quantum dots (QDs) as donors in fluorescence resonance energy transfer (FRET). The surface of paper was modified with imidazole groups to immobilize two types of QD-probe oligonucleotide conjugates that were assembled in solution. Green-emitting QDs (gQDs) and red-emitting QDs (rQDs) served as donors with Cy3 and Alexa Fluor 647 (A647) acceptors. The gQD/Cy3 FRET pair served as an internal standard, while the rQD/A647 FRET pair served as a detection channel, combining the control and analytical test zones in one physical location. Hybridization of dye-labeled oligonucleotide targets provided the proximity for FRET sensitized emission from the acceptor dyes, which served as an analytical signal. Hybridization assays in the multicolor format provided a limit of detection of 90 fmol and an upper limit of dynamic range of 3.5 pmol. The use of an array of detection zones was designed to provide improved analytical figures of merit compared to that which could be achieved on one type of array design in terms of relative concentration of multicolor QDs. The hybridization assays showed excellent resistance to nonspecific adsorption of oligonucleotides. Selectivity of the two-plex hybridization assay was demonstrated by single nucleotide polymorphism (SNP) detection at a contrast ratio of 50:1. Additionally, it is shown that the use of preformed QD-probe oligonucleotide conjugates and consideration of the relative number density of the two types of QD-probe conjugates in the two-color assay format is advantageous to maximize assay sensitivity and the upper limit of dynamic range.

  3. Neutron Resonance Parameters of 238U and the Calculated Cross Sections from the Reich-Moore Analysis of Experimental Data in the Neutron Energy Range from 0 keV to 20 keV

    Energy Technology Data Exchange (ETDEWEB)

    Derrien, H

    2005-12-05

    The neutron resonance parameters of {sup 238}U were obtained from a SAMMY analysis of high-resolution neutron transmission measurements and high-resolution capture cross section measurements performed at the Oak Ridge Electron Linear Accelerator (ORELA) in the years 1970-1990, and from more recent transmission and capture cross section measurements performed at the Geel Linear Accelerator (GELINA). Compared with previous evaluations, the energy range for this resonance analysis was extended from 10 to 20 keV, taking advantage of the high resolution of the most recent ORELA transmission measurements. The experimental database and the method of analysis are described in this report. The neutron transmissions and the capture cross sections calculated with the resonance parameters are compared with the experimental data. A description is given of the statistical properties of the resonance parameters and of the recommended values of the average parameters. The new evaluation results in a slight decrease of the effective capture resonance integral and improves the prediction of integral thermal benchmarks by 70 pcm to 200 pcm.

  4. Long-range interactions in the effective low-energy Hamiltonian of Sr2IrO4 : A core-to-core resonant inelastic x-ray scattering study

    Science.gov (United States)

    Agrestini, S.; Kuo, C.-Y.; Moretti Sala, M.; Hu, Z.; Kasinathan, D.; Ko, K.-T.; Glatzel, P.; Rossi, M.; Cafun, J.-D.; Kvashnina, K. O.; Matsumoto, A.; Takayama, T.; Takagi, H.; Tjeng, L. H.; Haverkort, M. W.

    2017-05-01

    We have investigated the electronic structure of Sr2IrO4 using core-to-core resonant inelastic x-ray scattering. The experimental spectra can be well reproduced using ab initio density functional theory based multiplet ligand field theory calculations, thereby validating these calculations. We found that the low-energy, effective Ir t2 g orbitals are practically degenerate in their crystal-field energy. We uncovered that Sr2IrO4 and iridates in general are negative charge transfer systems with large covalency and a substantial oxygen ligand hole character in the Ir t2 g Wannier orbitals. This has far reaching consequences, as not only the on-site crystal-field energies are determined by the long-range crystal structure, but, more significantly, magnetic exchange interactions will have long-range distance dependent anisotropies in the spin direction. These findings set constraints and show pathways for the design of d5 materials that can host compasslike magnetic interactions.

  5. The resonance energy of benzene: a revisit.

    Science.gov (United States)

    Mo, Yirong

    2009-04-30

    Zielinski and van Lenthe recently extended the block-localized wave function (BLW) method by introducing the resonating BLW (RBLW) method and performed test calculations on hexagonal H(6) and benzene [J. Phys. Chem. A 2008, 112, 13197]. However, the Pauling's resonance energies from their RBLW and ab initio valence bond (VB) calculations were greatly underestimated largely due to the imperfect use of either one-electron orbitals (method = delocal) or resonance structures (method = local). Whereas it has been well recognized that electronic resonance within a molecular system plays a stabilizing role, there are many indirect experimental evidences available to evaluate the resonance energy and, thus, to justify computational results. Here we used the BLW method, which can be regarded as the simplest variant of modern ab initio VB theory, to re-evaluate the resonance energy of benzene at the B3LYP level, following the original definition by Pauling and Wheland, who obtained the resonance energy "by subtracting the actual energy of the molecule in question from that of the most stable contributing structure". The computed vertical resonance energy (or quantum mechanical resonance energy) in benzene is 88.8, 92.2, or 87.9 kcal/mol with the basis sets of 6-31G(d), 6-311+G(d,p), or cc-pVTZ, respectively, while the adiabatic resonance energy (or theoretical resonance energy) is 61.4, 63.2, or 62.4 kcal/mol, exhibiting insignificant basis set dependency for moderate basis sets. In line with predictions, the geometry optimization of the elusive cyclohexatriene (i.e., the Kekule structure) with the BLW method also resulted in carbon-carbon bond lengths (e.g., 1.322 and 1.523 A with the cc-pVTZ basis set) comparable to those in ethylene or ethane.

  6. Imaging using long range dipolar field effects Nuclear magnetic resonance

    CERN Document Server

    Gutteridge, S

    2002-01-01

    The work in this thesis has been undertaken by the except where indicated in reference, within the Magnetic Resonance Centre, at the University of Nottingham during the period from October 1998 to March 2001. This thesis details the different characteristics of the long range dipolar field and its application to magnetic resonance imaging. The long range dipolar field is usually neglected in nuclear magnetic resonance experiments, as molecular tumbling decouples its effect at short distances. However, in highly polarised samples residual long range components have a significant effect on the evolution of the magnetisation, giving rise to multiple spin echoes and unexpected quantum coherences. Three applications utilising these dipolar field effects are documented in this thesis. The first demonstrates the spatial sensitivity of the signal generated via dipolar field effects in structured liquid state samples. The second utilises the signal produced by the dipolar field to create proton spin density maps. Thes...

  7. High Energy Single Frequency Resonant Amplifier Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR phase I project proposes a single frequency high energy resonant amplifier for remote sensing. Current state-of-art technologies can not provide all...

  8. Storm surge and tidal range energy

    Science.gov (United States)

    Lewis, Matthew; Angeloudis, Athanasios; Robins, Peter; Evans, Paul; Neill, Simon

    2017-04-01

    The need to reduce carbon-based energy sources whilst increasing renewable energy forms has led to concerns of intermittency within a national electricity supply strategy. The regular rise and fall of the tide makes prediction almost entirely deterministic compared to other stochastic renewable energy forms; therefore, tidal range energy is often stated as a predictable and firm renewable energy source. Storm surge is the term used for the non-astronomical forcing of tidal elevation, and is synonymous with coastal flooding because positive storm surges can elevate water-levels above the height of coastal flood defences. We hypothesis storm surges will affect the reliability of the tidal range energy resource; with negative surge events reducing the tidal range, and conversely, positive surge events increasing the available resource. Moreover, tide-surge interaction, which results in positive storm surges more likely to occur on a flooding tide, will reduce the annual tidal range energy resource estimate. Water-level data (2000-2012) at nine UK tide gauges, where the mean tidal amplitude is above 2.5m and thus suitable for tidal-range energy development (e.g. Bristol Channel), were used to predict tidal range power with a 0D modelling approach. Storm surge affected the annual resource estimate by between -5% to +3%, due to inter-annual variability. Instantaneous power output were significantly affected (Normalised Root Mean Squared Error: 3%-8%, Scatter Index: 15%-41%) with spatial variability and variability due to operational strategy. We therefore find a storm surge affects the theoretical reliability of tidal range power, such that a prediction system may be required for any future electricity generation scenario that includes large amounts of tidal-range energy; however, annual resource estimation from astronomical tides alone appears sufficient for resource estimation. Future work should investigate water-level uncertainties on the reliability and

  9. Enhanced energy storage in chaotic optical resonators

    KAUST Repository

    Liu, Changxu

    2013-05-05

    Chaos is a phenomenon that occurs in many aspects of contemporary science. In classical dynamics, chaos is defined as a hypersensitivity to initial conditions. The presence of chaos is often unwanted, as it introduces unpredictability, which makes it difficult to predict or explain experimental results. Conversely, we demonstrate here how chaos can be used to enhance the ability of an optical resonator to store energy. We combine analytic theory with ab initio simulations and experiments in photonic-crystal resonators to show that a chaotic resonator can store six times more energy than its classical counterpart of the same volume. We explain the observed increase by considering the equipartition of energy among all degrees of freedom of the chaotic resonator (that is, the cavity modes) and discover a convergence of their lifetimes towards a single value. A compelling illustration of the theory is provided by enhanced absorption in deformed polystyrene microspheres. © 2013 Macmillan Publishers Limited. All rights reserved.

  10. Effective-range dependence of resonant Fermi gases

    Science.gov (United States)

    Schonenberg, L. M.; Conduit, G. J.

    2017-01-01

    A Fermi gas of cold atoms allows precise control over the dimensionless effective range, kFReff , of the Feshbach resonance. Our pseudopotential formalism allows us to create smooth potentials with effective range, -2 ≤kFReff≤2 , which we use for a variational and diffusion Monte Carlo study of the ground state of a unitary Fermi gas. We report values for the universal constants of ξ =0.388 (1 ) and ζ =0.087 (1 ) , and compute the condensate fraction, momentum distribution, and pair correlations functions. Finally, we show that a gas with kFReff≳1.9 is thermodynamically unstable.

  11. Resonance energy transfer: Dye to metal nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Wari, M. N.; Pujar, G. H.; Inamdar, S. R., E-mail: him-lax3@yahoo.com [Laser Spectroscopy Programme, Department of Physics, Karnatak University, Dharwad-580003 (India)

    2015-06-24

    In the present study, surface energy transfer (SET) from Coumarin 540A (C540 A) to Gold nanoparticle (Au) is demonstrated. The observed results show pronounced effect on the photoluminescence intensity and shortening of the lifetime of Coumarin 540A upon interaction with the spherical gold nanoparticle, also there are measured effects on radiative rate of the dye. Experimental results are analyzed with fluorescence resonance energy transfer (FRET) and SET theories. The results obtained from distance-dependent quenching provide experimental evidence that the efficiency curve slope and distance of quenching is best modeled by surface energy transfer process.

  12. Resonance Energy Transfer Molecular Imaging Application in Biomedicine

    Directory of Open Access Journals (Sweden)

    NIE Da-hong1,2;TANG Gang-hua1,3

    2016-11-01

    Full Text Available Resonance energy transfer molecular imaging (RETI can markedly improve signal intensity and tissue penetrating capacity of optical imaging, and have huge potential application in the deep-tissue optical imaging in vivo. Resonance energy transfer (RET is an energy transition from the donor to an acceptor that is in close proximity, including non-radiative resonance energy transfer and radiative resonance energy transfer. RETI is an optical imaging technology that is based on RET. RETI mainly contains fluorescence resonance energy transfer imaging (FRETI, bioluminescence resonance energy transfer imaging (BRETI, chemiluminescence resonance energy transfer imaging (CRETI, and radiative resonance energy transfer imaging (RRETI. RETI is the hot field of molecular imaging research and has been widely used in the fields of biology and medicine. This review mainly focuses on RETI principle and application in biomedicine.

  13. How resonance assists hydrogen bonding interactions: an energy decomposition analysis.

    Science.gov (United States)

    Beck, John Frederick; Mo, Yirong

    2007-01-15

    Block-localized wave function (BLW) method, which is a variant of the ab initio valence bond (VB) theory, was employed to explore the nature of resonance-assisted hydrogen bonds (RAHBs) and to investigate the mechanism of synergistic interplay between pi delocalization and hydrogen-bonding interactions. We examined the dimers of formic acid, formamide, 4-pyrimidinone, 2-pyridinone, 2-hydroxpyridine, and 2-hydroxycyclopenta-2,4-dien-1-one. In addition, we studied the interactions in beta-diketone enols with a simplified model, namely the hydrogen bonds of 3-hydroxypropenal with both ethenol and formaldehyde. The intermolecular interaction energies, either with or without the involvement of pi resonance, were decomposed into the Hitler-London energy (DeltaEHL), polarization energy (DeltaEpol), charge transfer energy (DeltaECT), and electron correlation energy (DeltaEcor) terms. This allows for the examination of the character of hydrogen bonds and the impact of pi conjugation on hydrogen bonding interactions. Although it has been proposed that resonance-assisted hydrogen bonds are accompanied with an increasing of covalency character, our analyses showed that the enhanced interactions mostly originate from the classical dipole-dipole (i.e., electrostatic) attraction, as resonance redistributes the electron density and increases the dipole moments in monomers. The covalency of hydrogen bonds, however, changes very little. This disputes the belief that RAHB is primarily covalent in nature. Accordingly, we recommend the term "resonance-assisted binding (RAB)" instead of "resonance-assisted hydrogen bonding (RHAB)" to highlight the electrostatic, which is a long-range effect, rather than the electron transfer nature of the enhanced stabilization in RAHBs. Copyright (c) 2006 Wiley Periodicals, Inc.

  14. Energy dependence of polymer gels in the orthovoltage energy range

    Directory of Open Access Journals (Sweden)

    Yvonne Roed

    2014-03-01

    Full Text Available Purpose: Ortho-voltage energies are often used for treatment of patients’ superficial lesions, and also for small- animal irradiations. Polymer-Gel dosimeters such as MAGAT (Methacrylic acid Gel and THPC are finding increasing use for 3-dimensional verification of radiation doses in a given treatment geometry. For mega-voltage beams, energy dependence of MAGAT has been quoted as nearly energy-independent. In the kilo-voltage range, there is hardly any literature to shade light on its energy dependence.Methods: MAGAT was used to measure depth-dose for 250 kVp beam. Comparison with ion-chamber data showed a discrepancy increasing significantly with depth. An over-response as much as 25% was observed at a depth of 6 cm.Results and Conclusion: Investigation concluded that 6 cm water in the beam resulted in a half-value-layer (HVL change from 1.05 to 1.32 mm Cu. This amounts to an effective-energy change from 81.3 to 89.5 keV. Response measurements of MAGAT at these two energies explained the observed discrepancy in depth-dose measurements. Dose-calibration curves of MAGAT for (i 250 kVp beam, and (ii 250 kVp beam through 6 cm of water column are presented showing significant energy dependence.-------------------Cite this article as: Roed Y, Tailor R, Pinksy L, Ibbott G. Energy dependence of polymer gels in the orthovoltage energy range. Int J Cancer Ther Oncol 2014; 2(2:020232. DOI: 10.14319/ijcto.0202.32 

  15. Nonextensive kinetics of fluorescence resonance energy transfer.

    Science.gov (United States)

    Rolinski, Olaf J; Birch, David J S

    2008-10-14

    Some fluorescence dyes in complex media, such as those found in biology, demonstrate nonextensive kinetics, which implies representing their fluorescence decays in terms of lifetime distributions rather than simple exponentials. Complex kinetics usually discourage application to lifetime sensors, as it is believed, that additional molecular mechanisms employed for detection of an analyte will make the resulting kinetics ambiguous and the sensor response inconclusive. In this paper we investigate theoretically the applicability of complex dye kinetics as a fluorescence resonance energy transfer based lifetime sensor and demonstrate that the nonextensive nature of its kinetics does not decrease the sensing performance, and indeed even provides richer structural information than a simple exponential behavior.

  16. Active resonant subwavelength grating for scannerless range imaging sensors.

    Energy Technology Data Exchange (ETDEWEB)

    Kemme, Shanalyn A.; Nellums, Robert O.; Boye, Robert R.; Peters, David William

    2006-11-01

    In this late-start LDRD, we will present a design for a wavelength-agile, high-speed modulator that enables a long-term vision for the THz Scannerless Range Imaging (SRI) sensor. It takes the place of the currently-utilized SRI micro-channel plate which is limited to photocathode sensitive wavelengths (primarily in the visible and near-IR regimes). Two of Sandia's successful technologies--subwavelength diffractive optics and THz sources and detectors--are poised to extend the capabilities of the SRI sensor. The goal is to drastically broaden the SRI's sensing waveband--all the way to the THz regime--so the sensor can see through image-obscuring, scattering environments like smoke and dust. Surface properties, such as reflectivity, emissivity, and scattering roughness, vary greatly with the illuminating wavelength. Thus, objects that are difficult to image at the SRI sensor's present near-IR wavelengths may be imaged more easily at the considerably longer THz wavelengths (0.1 to 1mm). The proposed component is an active Resonant Subwavelength Grating (RSG). Sandia invested considerable effort on a passive RSG two years ago, which resulted in a highly-efficient (reflectivity greater than gold), wavelength-specific reflector. For this late-start LDRD proposal, we will transform the passive RSG design into an active laser-line reflector.

  17. Zero-range effective field theory for resonant wino dark matter. Part I. Framework

    Science.gov (United States)

    Braaten, Eric; Johnson, Evan; Zhang, Hong

    2017-11-01

    The most dramatic "Sommerfeld enhancements" of neutral-wino-pair annihilation occur when the wino mass is near a critical value where there is a zero-energy S-wave resonance at the neutral-wino-pair threshold. Near such a critical mass, low-energy winos can be described by a zero-range effective field theory in which the winos interact nonperturbatively through a contact interaction. The effective field theory is controlled by a renormalization-group fixed point at which the neutral and charged winos are degenerate in mass and their scattering length is infinite. The parameters of the zero-range effective field theory can be determined by matching wino-wino scattering amplitudes calculated by solving the Schrödinger equation for winos interacting through a potential due to the exchange of weak gauge bosons. If the wino mass is larger than the critical value, the resonance is a wino-pair bound state. The power of the zero-range effective field theory is illustrated by calculating the rate for formation of the bound state in the collision of two neutral winos through the emission of two soft photons.

  18. Zero-Range Effective Field Theory for Resonant Wino Dark Matter

    Science.gov (United States)

    Johnson, Evan; Braaten, Eric; Zhang, Hong

    2017-01-01

    The most dramatic ``Sommerfeld enhancements'' of neutral-wino-pair annihilation occur when the wino mass is tuned to near critical values where there is a zero-energy S-wave resonance at the neutral-wino-pair threshold. If the wino mass is larger than the critical value, the resonance is a wino-pair bound state. If the wino mass is near a critical value, low-energy winos can be described by a zero-range effective field theory in which the winos interact nonperturbatively through a contact interaction. The parameters of the zero-range effective field theory can be determined by matching wino scattering amplitudes calculated by solving the Schrödinger equation for a nonrelativistic effective field theory in which the winos interact nonperturbatively through a potential due to the exchange of weak gauge bosons. The power of the zero-range effective field theory is illustrated by calculating the rate for formation of the bound state in the collision of two neutral winos through the emission of two soft photons. Supported in part by DOE grant DE-FG02-05ER15715.

  19. Spectroscopic evidence of resonance energy transfer mechanism from PbS QDs to bulk silicon

    Directory of Open Access Journals (Sweden)

    Bernechea M.

    2013-06-01

    Full Text Available In this work, we study the efficiency of the resonance energy transfer from PbS quantum dots to bulk silicon. We present spectroscopic evidence that resonance energy transfer from PbS quantum dots to bulk silicon can be an efficient process for separation distances below 12 nm. Temperature measurements are also presented for PbS quantum dots deposited on glass and silicon with 5 nm and 20nm spacer thicknesses substrates. Our findings show that the resonance energy transfer efficiency remains constant over the 50K to 300K temperature range.

  20. Dual resonant structure for energy harvesting from random vibration sources at low frequency

    Directory of Open Access Journals (Sweden)

    Shanshan Li

    2016-01-01

    Full Text Available We introduce a design with dual resonant structure which can harvest energy from random vibration sources at low frequency range. The dual resonant structure consists of two spring-mass subsystems with different frequency responses, which exhibit strong coupling and broad bandwidth when the two masses collide with each other. Experiments with piezoelectric elements show that the energy harvesting device with dual resonant structure can generate higher power output than the sum of the two separate devices from random vibration sources.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-12-01

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

  2. Optimal all-optical switching of a microcavity resonance in the telecom range using the electronic Kerr effect.

    Science.gov (United States)

    Yüce, Emre; Ctistis, Georgios; Claudon, Julien; Gérard, Jean-Michel; Vos, Willem L

    2016-01-11

    We have switched GaAs/AlAs and AlGaAs/AlAs planar microcavities that operate in the "Original" (O) telecom band by exploiting the instantaneous electronic Kerr effect. We observe that the resonance frequency reversibly shifts within one picosecond when the nanostructure is pumped with low-energy photons. We investigate experimentally and theoretically the role of several parameters: the material backbone and its electronic bandgap, the quality factor, and the duration of the switch pulse. The magnitude of the frequency shift is reduced when the backbone of the central λ-layer has a greater electronic bandgap compared to the cavity resonance frequency and the frequency of the pump. This observation is caused by the fact that pumping with photon energies near the bandgap resonantly enhances the switched magnitude. We thus find that cavities operating in the telecom O-band are more amenable to ultrafast Kerr switching than those operating at lower frequencies, such as the C-band. Our results indicate that the large bandgap of AlGaAs/AlAs cavity allows to tune both the pump and the probe to the telecom range to perform Kerr switching without detrimental two-photon absorption. We observe that the magnitude of the resonance frequency shift decreases with increasing quality factor of the cavity. Our model shows that the magnitude of the resonance frequency shift depends on the pump pulse duration and is maximized when the duration matches the cavity storage time to within a factor two. In our experiments, we obtain a maximum shift of the cavity resonance relative to the cavity linewidth of 20%. We project that the shift of the cavity resonance can be increased twofold with a pump pulse duration that better matches the cavity storage time. We provide the essential parameter settings for different materials so that the frequency shift of the cavity resonance can be maximized using the electronic Kerr effect.

  3. Energy Dissipation in Graphene Mechanical Resonators with and without Free Edges

    Directory of Open Access Journals (Sweden)

    Makoto Takamura

    2016-09-01

    Full Text Available Graphene-based nanoelectromechanical systems (NEMS have high future potential to realize sensitive mass and force sensors owing to graphene’s low mass density and exceptional mechanical properties. One of the important remaining issues in this field is how to achieve mechanical resonators with a high quality factor (Q. Energy dissipation in resonators decreases Q, and suppressing it is the key to realizing sensitive sensors. In this article, we review our recent work on energy dissipation in doubly-clamped and circular drumhead graphene resonators. We examined the temperature (T dependence of the inverse of a quality factor ( Q - 1 to reveal what the dominant dissipation mechanism is. Our doubly-clamped trilayer resonators show a characteristic Q - 1 -T curve similar to that observed in monolayer resonators: Q - 1 ∝ T 2 above ∼100 K and ∝ T 0.3 below ∼100 K. By comparing our results with previous experimental and theoretical results, we determine that the T 2 and T 0.3 dependences can be attributed to tensile strain induced by clamping metals and vibrations at the free edges in doubly-clamped resonators, respectively. The Q - 1 -T curve in our circular drumhead resonators indicates that removing free edges and clamping metal suppresses energy dissipation in the resonators, resulting in a linear T dependence of Q - 1 in a wide temperature range.

  4. Intrinsic Energy Dissipation Limits in Nano and Micromechanical Resonators

    Science.gov (United States)

    Iyer, Srikanth Subramanian

    Resonant microelectromechanical Systems (MEMS) have enabled miniaturization of high-performance inertial sensors, radio-frequency filters, timing references and mass-based chemical sensors. Despite the increasing prevalence of MEMS resonators for these applications, the energy dissipation in these structures is not well-understood. Accurate prediction of the energy loss and the resulting quality factor (Q) has significant design implications because it is directly related to device performance metrics including sensitivity for resonant sensors, bandwidth for radio-frequency filters and phase-noise for timing references. In order to assess the future potential for MEMS resonators it is critically important to evaluate the energy dissipation limits, which will dictate the ultimate performance resonant MEMS devices can achieve. This work focuses on the derivation and evaluation of the intrinsic mechanical energy dissipation limit for single-crystal nano and micromechanical resonators due to anharmonic phonon-phonon scattering in the Akhiezer regime. The energy loss is derived using perturbation theory and the linearized Boltzmann transport equation for phonons, and includes the direction and polarization dependent mode-Gruneisen parameters in order to capture the strain-induced anharmonicity among phonon branches. Evaluation of the quality factor limit reveals that Akhiezer damping, previously thought to depend only on material properties, has a strong dependence on crystal orientation and resonant mode shape. The robust model provides a dissipation limit for all resonant modes including shear-mode vibrations, which have significantly reduced energy loss because dissipative phonon-phonon scattering is restricted to volume-preserving phonon branches, indicating that Lame or wine-glass mode resonators will have the highest upper limit on mechanical efficiency. Finally, the analytical dissipation model is integrated with commercial finite element software in order to

  5. Role of near threshold resonances in intermediate energy nuclear ...

    Indian Academy of Sciences (India)

    2014-11-04

    Nov 4, 2014 ... Abstract. The presence of a resonance close to the threshold strongly effects the dynamics of the interacting particles at low energies. Production of 12C, the element for life, in 4He burning in. Sun is a classic example of such a situation. In intermediate energy nuclear physics, this situation arises in the ...

  6. Role of near threshold resonances in intermediate energy nuclear ...

    Indian Academy of Sciences (India)

    2014-11-04

    Nov 4, 2014 ... The presence of a resonance close to the threshold strongly effects the dynamics of the interacting particles at low energies. Production of 12C, the element for life, in 4He burning in Sun is a classic example of such a situation. In intermediate energy nuclear physics, this situation arises in the interactions of ...

  7. ENERGY GAIN BY MEANS OF RESONANCE IN THE TESLA COIL

    Directory of Open Access Journals (Sweden)

    Yu. Batygin

    2016-12-01

    Full Text Available An analytical review of publications on the problem, first formulated by Nikola Tesla, generating «free» energy from the air in the surrounding space has been presented. The hypothesis of the resonance phenomenon as a «key» to the air energy has been advanced. The main unsolved problem is the extrac-tion of «free» energy (proposed to call it «resonance» and its supply to the electrical load have been noted. It is expected that the quality factor of the secondary circuit must be large enough.

  8. Energy-range relations for hadrons in nuclear matter

    Science.gov (United States)

    Strugalski, Z.

    1985-01-01

    Range-energy relations for hadrons in nuclear matter exist similarly to the range-energy relations for charged particles in materials. When hadrons of GeV kinetic energies collide with atomic nuclei massive enough, events occur in which incident hadron is stopped completely inside the target nucleus without causing particle production - without pion production in particular. The stoppings are always accompanied by intensive emission of nucleons with kinetic energy from about 20 up to about 400 MeV. It was shown experimentally that the mean number of the emitted nucleons is a measure of the mean path in nuclear matter in nucleons on which the incident hadrons are stopped.

  9. Impedance Based Analysis and Design of Harmonic Resonant Controller for a Wide Range of Grid Impedance

    DEFF Research Database (Denmark)

    Kwon, Jun Bum; Wang, Xiongfei; Blaabjerg, Frede

    2014-01-01

    This paper investigates the effect of grid impedance variation on harmonic resonant current controllers for gridconnected voltage source converters by means of impedance-based analysis. It reveals that the negative harmonic resistances tend to be derived from harmonic resonant controllers...... in the closed-loop output admittance of converter. Such negative resistances may interact with the grid impedance resulting in steady state error or unstable harmonic compensation. To deal with this problem, a design guideline for harmonic resonant controllers under a wide range of grid impedance is proposed...

  10. Plasmon-Exciton Resonant Energy Transfer: Across Scales Hybrid Systems

    Directory of Open Access Journals (Sweden)

    Mohamed El Kabbash

    2016-01-01

    Full Text Available The presence of an excitonic element in close proximity of a plasmonic nanostructure, under certain conditions, may lead to a nonradiative resonant energy transfer known as Exciton Plasmon Resonant Energy Transfer (EPRET process. The exciton-plasmon coupling and dynamics have been intensely studied in the last decade; still many relevant aspects need more in-depth studies. Understanding such phenomenon is not only important from fundamental viewpoint, but also essential to unlock many promising applications. In this review we investigate the plasmon-exciton resonant energy transfer in different hybrid systems at the nano- and mesoscales, in order to gain further understanding of such processes across scales and pave the way towards active plasmonic devices.

  11. Electrostatic energy harvesting device with dual resonant structure for wideband random vibration sources at low frequency.

    Science.gov (United States)

    Zhang, Yulong; Wang, Tianyang; Zhang, Ai; Peng, Zhuoteng; Luo, Dan; Chen, Rui; Wang, Fei

    2016-12-01

    In this paper, we present design and test of a broadband electrostatic energy harvester with a dual resonant structure, which consists of two cantilever-mass subsystems each with a mass attached at the free edge of a cantilever. Comparing to traditional devices with single resonant frequency, the proposed device with dual resonant structure can resonate at two frequencies. Furthermore, when one of the cantilever-masses is oscillating at resonance, the vibration amplitude is large enough to make it collide with the other mass, which provides strong mechanical coupling between the two subsystems. Therefore, this device can harvest a decent power output from vibration sources at a broad frequency range. During the measurement, continuous power output up to 6.2-9.8 μW can be achieved under external vibration amplitude of 9.3 m/s2 at a frequency range from 36.3 Hz to 48.3 Hz, which means the bandwidth of the device is about 30% of the central frequency. The broad bandwidth of the device provides a promising application for energy harvesting from the scenarios with random vibration sources. The experimental results indicate that with the dual resonant structure, the vibration-to-electricity energy conversion efficiency can be improved by 97% when an external random vibration with a low frequency filter is applied.

  12. Energy Harvesting with Coupled Magnetorestrictive Resonators

    Science.gov (United States)

    2013-09-01

    concentration of iron and gallium as 83 and 17%, respectively. Here, we describe a coupled system of meso- scale (1- to 10-cm) cantilever beams. The coupled... Cantilever beam with magnetostrictive energy harvesting transducer ............................... 3  4. Mechanical domain lumped element model of the...aircraft, and machines. 1.3 BACKGROUND At mesoscale, the dominant transduction mechanisms are electromagnetic and piezoelectric . The

  13. Design of narrow band photonic filter with compact MEMS for tunable resonant wavelength ranging 100 nm

    Directory of Open Access Journals (Sweden)

    Guanquan Liang

    2011-12-01

    Full Text Available A prototype of planar silicon photonic structure is designed and simulated to provide narrow resonant line-width (∼2 nm in a wide photonic band gap (∼210 nm with broad tunable resonant wavelength range (∼100 nm around the optical communication wavelength 1550 nm. This prototype is based on the combination of two modified basic photonic structures, i.e. a split tapered photonic crystal micro-cavity embedded in a photonic wire waveguide, and a slot waveguide with narrowed slabs. This prototype is then further integrated with a MEMS (microelectromechanical systems based electrostatic comb actuator to achieve “coarse tune” and “fine tune” at the same time for wide range and narrow-band filtering and modulating. It also provides a wide range tunability to achieve the designed resonance even fabrication imperfection occurs.

  14. An Optimized Control for LLC Resonant Converter with Wide Load Range

    Science.gov (United States)

    Xi, Xia; Qian, Qinsong

    2017-05-01

    This paper presents an optimized control which makes LLC resonant converters operate with a wider load range and provides good closed-loop performance. The proposed control employs two paralleled digital compensations to guarantee the good closed-loop performance in a wide load range during the steady state, an optimized trajectory control will take over to change the gate-driving signals immediately at the load transients. Finally, the proposed control has been implemented and tested on a 150W 200kHz 400V/24V LLC resonant converter and the result validates the proposed method.

  15. High-q microring resonator with narrow free spectral range for pulse repetition rate multiplication

    DEFF Research Database (Denmark)

    Pu, Minhao; Ji, Hua; Frandsen, Lars Hagedorn

    2009-01-01

    We demonstrate a silicon-on-insulator microring resonator with a free-spectral-range of 0.32 nm, an extinction ratio of 27 dB, and a quality factor of ~140900 at 1550 nm that is used for pulse repetition-rate multiplication from 10 to 40 GHz.......We demonstrate a silicon-on-insulator microring resonator with a free-spectral-range of 0.32 nm, an extinction ratio of 27 dB, and a quality factor of ~140900 at 1550 nm that is used for pulse repetition-rate multiplication from 10 to 40 GHz....

  16. 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.

  17. Nanophotonic control of Forster Resonance Energy Transfer

    CERN Document Server

    Zijlstra, Niels; Vos, Willem L; Subramaniam, Vinod; Blum, Christian

    2011-01-01

    Here we report on the experimental details of a study on the influence of the photonic environment on the emission of a FRET system. We modified the local density of optical states (LDOS) by placing the FRET system at precisely defined distances to a metallic mirror. We measured the energy donor lifetime in the presence of the FRET acceptor and the lifetime of an identical sample lacking an acceptor fluorophore for different LDOS. From the lifetimes we determined the FRET rate as well as the FRET efficiency for each sampled LDOS.

  18. Energy calibration at LEP using Nuclear Magnetic Resonance probes

    CERN Document Server

    Bravin, Enrico; Mugnai, G

    1998-01-01

    The accurate Standard Model investigations carried out at LEP require knowledge of the beam energies of the order of a few 10-5. The resonant depolarisation method, used for absolute calibration in de dicated experiments, cannot be used to monitor continuously the beam energy during the physics runs. Moreover appreciable polarisation of the beams has not been measured above energies of 55 GeV. A me thod for continuous energy monitoring based on Nuclear Magnetic Resonance (NMR) probes mounted in tunnel magnets has been in use at LEP since 1995. The average field of the dipole magnets is sampled v ia 24 NMR probes mounted in the gap of the C-shaped yokes on top of the vacuum chamber. The probes are distributed over the 27 km of the accelerator. The probes are used for the continuous monitoring of the field during LEP operation and to determine the absolute field value.

  19. Thermal effects on parallel resonance energy of whistler mode wave

    Indian Academy of Sciences (India)

    Abstract. In this short communication, we have evaluated the effect of thermal velocity of the plasma particles on the energy of resonantly interacting energetic electrons with the propagating whistler mode waves as a function of wave frequency and L-value for the normal and disturbed magnetospheric conditions. During the ...

  20. High energy resolution off-resonant X-ray spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wojciech, Blachucki [Univ. of Fribourg (Switzerland). Dept. of Physics

    2015-10-16

    This work treats of the high energy resolution off-resonant X-ray spectroscopy (HEROS) method of determining the density of unoccupied electronic states in the vicinity of the absorption edge. HEROS is an alternative to the existing X-ray absorption spectroscopy (XAS) methods and opens the way for new studies not achievable before.

  1. Fluorescence resonance energy transfer (FRET) measurement by gradual acceptor photobleaching.

    NARCIS (Netherlands)

    van Munster, E.B.; Kremers, G.J.; Adjobo Hermans, M.J.W.; Gadella, Th.W.J.

    2005-01-01

    Fluorescence resonance energy transfer (FRET) is an extremely effective tool to detect molecular interaction at suboptical resolutions. One of the techniques for measuring FRET is acceptor photobleaching: the increase in donor fluorescence after complete acceptor photobleaching is a measure of the

  2. Fluorescence resonance energy transfer from tryptophan in human ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 119; Issue 2. Fluorescence resonance energy transfer from tryptophan in human serum albumin to a bioactive indoloquinolizine system. Paramita Das Arabinda Mallick Basudeb Haldar Alok Chakrabarty Nitin Chattopadhyay. Volume 119 Issue 2 March 2007 pp 77-82 ...

  3. Ultrafast fluorescence resonance energy transfer in a bile salt ...

    Indian Academy of Sciences (India)

    Fluorescence resonance energy transfer (FRET) from Coumarin 153 (C153) to Rhodamine 6G (R6G) in a secondary aggregate of a bile salt (sodium deoxycholate, NaDC) is studied by femtosecond up-conversion. The emission spectrum of C153 in NaDC is analysed in terms of two spectra-one with emission maximum at ...

  4. Average Neutron Total Cross Sections in the Unresolved Energy Range From ORELA High Resolutio Transmission Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Derrien, H

    2004-05-27

    Average values of the neutron total cross sections of {sup 233}U, {sup 235}U, {sup 238}U, and {sup 239}Pu have been obtained in the unresolved resonance energy range from high-resolution transmission measurements performed at ORELA in the past two decades. The cross sections were generated by correcting the effective total cross sections for the self-shielding effects due to the resonance structure of the data. The self-shielding factors were found by calculating the effective and true cross sections with the computer code SAMMY for the same Doppler and resolution conditions as for the transmission measurements, using an appropriate set of resonance parameters. Our results are compared to results of previous measurements and to the current ENDF/B-VI data.

  5. Fluorescence Resonance Energy Transfer Systems in Supramolecular Macrocyclic Chemistry.

    Science.gov (United States)

    Lou, Xin-Yue; Song, Nan; Yang, Ying-Wei

    2017-09-29

    The fabrication of smart materials is gradually becoming a research focus in nanotechnology and materials science. An important criterion of smart materials is the capacity of stimuli-responsiveness, while another lies in selective recognition. Accordingly, supramolecular host-guest chemistry has proven a promising support for building intelligent, responsive systems; hence, synthetic macrocyclic hosts, such as calixarenes, cucurbiturils, cyclodextrins, and pillararenes, have been used as ideal building blocks. Meanwhile, manipulating and harnessing light artificially is always an intensive attempt for scientists in order to meet the urgent demands of technological developments. Fluorescence resonance energy transfer (FRET), known as a well-studied luminescent activity and also a powerful tool in spectroscopic area, has been investigated from various facets, of which the application range has been broadly expanded. In this review, the innovative collaboration between FRET and supramolecular macrocyclic chemistry will be presented and depicted with typical examples. Facilitated by the dynamic features of supramolecular macrocyclic motifs, a large variety of FRET systems have been designed and organized, resulting in promising optical materials with potential for applications in protein assembly, enzyme assays, diagnosis, drug delivery monitoring, sensing, photosynthesis mimicking and chemical encryption.

  6. Fluorescence Resonance Energy Transfer Systems in Supramolecular Macrocyclic Chemistry

    Directory of Open Access Journals (Sweden)

    Xin-Yue Lou

    2017-09-01

    Full Text Available The fabrication of smart materials is gradually becoming a research focus in nanotechnology and materials science. An important criterion of smart materials is the capacity of stimuli-responsiveness, while another lies in selective recognition. Accordingly, supramolecular host-guest chemistry has proven a promising support for building intelligent, responsive systems; hence, synthetic macrocyclic hosts, such as calixarenes, cucurbiturils, cyclodextrins, and pillararenes, have been used as ideal building blocks. Meanwhile, manipulating and harnessing light artificially is always an intensive attempt for scientists in order to meet the urgent demands of technological developments. Fluorescence resonance energy transfer (FRET, known as a well-studied luminescent activity and also a powerful tool in spectroscopic area, has been investigated from various facets, of which the application range has been broadly expanded. In this review, the innovative collaboration between FRET and supramolecular macrocyclic chemistry will be presented and depicted with typical examples. Facilitated by the dynamic features of supramolecular macrocyclic motifs, a large variety of FRET systems have been designed and organized, resulting in promising optical materials with potential for applications in protein assembly, enzyme assays, diagnosis, drug delivery monitoring, sensing, photosynthesis mimicking and chemical encryption.

  7. A graph theory approach to identify resonant and non-resonant transmission paths in statistical modal energy distribution analysis

    Science.gov (United States)

    Aragonès, Àngels; Maxit, Laurent; Guasch, Oriol

    2015-08-01

    Statistical modal energy distribution analysis (SmEdA) extends classical statistical energy analysis (SEA) to the mid frequency range by establishing power balance equations between modes in different subsystems. This circumvents the SEA requirement of modal energy equipartition and enables applying SmEdA to the cases of low modal overlap, locally excited subsystems and to deal with complex heterogeneous subsystems as well. Yet, widening the range of application of SEA is done at a price with large models because the number of modes per subsystem can become considerable when the frequency increases. Therefore, it would be worthwhile to have at one's disposal tools for a quick identification and ranking of the resonant and non-resonant paths involved in modal energy transmission between subsystems. It will be shown that previously developed graph theory algorithms for transmission path analysis (TPA) in SEA can be adapted to SmEdA and prove useful for that purpose. The case of airborne transmission between two cavities separated apart by homogeneous and ribbed plates will be first addressed to illustrate the potential of the graph approach. A more complex case representing transmission between non-contiguous cavities in a shipbuilding structure will be also presented.

  8. Internal resonance and low frequency vibration energy harvesting

    Science.gov (United States)

    Yang, Wei; Towfighian, Shahrzad

    2017-09-01

    A nonlinear vibration energy harvester with internal resonance is presented. The proposed harvester consists of two cantilevers, each with a permanent magnet on its tip. One cantilever has a piezoelectric layer at its base. When magnetic force is applied this two degrees-of-freedom nonlinear vibration system shows the internal resonance phenomenon that broadens the frequency bandwidth compared to a linear system. Three coupled partial differential equations are obtained to predict the dynamic behavior of the nonlinear energy harvester. The perturbation method of multiple scales is used to solve equations. Results from experiments done at different vibration levels with varying distances between the magnets validate the mathematical model. Experiments and simulations show the design outperforms the linear system by doubling the frequency bandwidth. Output voltage for frequency response is studied for different system parameters. The optimal load resistance is obtained for the maximum power in the internal resonance case. The results demonstrate that a design combining internal resonance and magnetic nonlinearity improves the efficiency of energy harvesting.

  9. X-ray laser resonator for the kilo-electron-volt range

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jie [Department of Chemistry, University of California, Irvine, California 92697 (United States); Key Laboratory for Laser Plasmas (Ministry of Education) and Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Tomov, Ivan V.; Er, Ali O.; Rentzepis, Peter M. [Department of Chemistry, University of California, Irvine, California 92697 (United States)

    2013-04-29

    We have designed, constructed, and tested an x-ray laser resonator operating in the hard x-ray, keV energy region. This ring x-ray laser cavity is formed by four highly oriented pyrolytic graphite crystals. The crystals are set at the Bragg angles that allow for the complete 360 Degree-Sign round trip of the 2.37 A, 5.23 keV L{sub {alpha}} line of neodymium. In addition, we also present experimental data of a similar ring laser resonator that utilizes the Cr K{sub {alpha}}, 5.41 keV, x-ray line to propagate through the four mirrors of the cavity. The specific properties of these x-ray laser resonator mirrors, including reflection losses and cavity arrangement, are presented.

  10. Stability Analysis and Trigger Control of LLC Resonant Converter for a Wide Operational Range

    Directory of Open Access Journals (Sweden)

    Zhijian Fang

    2017-09-01

    Full Text Available The gain of a LLC resonant converter can vary with the loads that can be used to improve the efficiency and power density for some special applications, where the maximum gain does not apply at the heaviest loads. However, nonlinear gain characteristics can make the converters unstable during a major disturbance. In this paper, the stability of an LLC resonant converter during a major disturbance is studied and a trigger control scheme is proposed to improve the converter’s stability by extending the converter’s operational range. Through in-depth analysis of the gain curve of the LLC resonant converter, we find that the switching frequency range is one of the key factors determining the system’s stability performance. The same result is also obtained from a mathematical point of view by utilizing the mixed potential function method. Then a trigger control method is proposed to make the LLC resonant converter stable even during a major disturbance, which can be used to extend the converter’s operational range. Finally, experimental results are given to verify the analysis and proposed control scheme.

  11. Characteristic energy range of electron scattering due to plasmaspheric hiss

    Science.gov (United States)

    Ma, Q.; Li, W.; Thorne, R. M.; Bortnik, J.; Reeves, G. D.; Kletzing, C. A.; Kurth, W. S.; Hospodarsky, G. B.; Spence, H. E.; Baker, D. N.; Blake, J. B.; Fennell, J. F.; Claudepierre, S. G.; Angelopoulos, V.

    2016-12-01

    We investigate the characteristic energy range of electron flux decay due to the interaction with plasmaspheric hiss in the Earth's inner magnetosphere. The Van Allen Probes have measured the energetic electron flux decay profiles in the Earth's outer radiation belt during a quiet period following the geomagnetic storm that occurred on 7 November 2015. The observed energy of significant electron decay increases with decreasing L shell and is well correlated with the energy band corresponding to the first adiabatic invariant μ = 4-200 MeV/G. The electron diffusion coefficients due to hiss scattering are calculated at L = 2-6, and the modeled energy band of effective pitch angle scattering is also well correlated with the constant μ lines and is consistent with the observed energy range of electron decay. Using the previously developed statistical plasmaspheric hiss model during modestly disturbed periods, we perform a 2-D Fokker-Planck simulation of the electron phase space density evolution at L = 3.5 and demonstrate that plasmaspheric hiss causes the significant decay of 100 keV-1 MeV electrons with the largest decay rate occurring at around 340 keV, forming anisotropic pitch angle distributions at lower energies and more flattened distributions at higher energies. Our study provides reasonable estimates of the electron populations that can be most significantly affected by plasmaspheric hiss and the consequent electron decay profiles.

  12. 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

  13. Energy transport in the presence of long-range interactions

    Science.gov (United States)

    Bagchi, Debarshee

    2017-10-01

    We study energy transport in the paradigmatic Hamiltonian mean-field (HMF) model and other related long-range interacting models using molecular dynamics simulations. We show that energy diffusion in the HMF model is subdiffusive in nature, which confirms a recently obtained intriguing result that, despite being globally interacting, this model is a thermal insulator in the thermodynamic limit. Surprisingly, when additional nearest-neighbor interactions are introduced to the HMF model, an energy superdiffusion is observed. We show that these results can be consistently explained by studying energy localization due to thermally generated intrinsic localized excitation modes (discrete breathers) in nonlinear discrete systems. Our analysis for the HMF model can also be readily extended to more generic long-range interacting models where the interaction strength decays algebraically with the (shortest) distance between two lattice sites. This reconciles many of the apparently counterintuitive results presented recently [C. Olivares and C. Anteneodo, Phys. Rev. E 94, 042117 (2016), 10.1103/PhysRevE.94.042117; D. Bagchi, Phys. Rev. E 95, 032102 (2017), 10.1103/PhysRevE.95.032102] concerning energy transport in two such long-range interacting models.

  14. 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.

  15. Wireless energy transfer through non-resonant magnetic coupling

    DEFF Research Database (Denmark)

    Peng, Liang; Breinbjerg, Olav; Mortensen, Asger

    2010-01-01

    We demonstrate by theoretical analysis and experimental verification that mid-range wireless energy transfer systems may take advantage of de-tuned coupling devices, without jeopardizing the energy transfer efficiency. Allowing for a modest de-tuning of the source coil, energy transfer systems co...

  16. A small-form-factor piezoelectric vibration energy harvester using a resonant frequency-down conversion

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Kyung Ho; Kim, Young-Cheol [Department of System Dynamics, Korea Institute of Machinery and Materials, 156 Gajeongbuk-Ro, Yuseong-Gu, Daejeon 305-343 (Korea, Republic of); Kim, Jae Eun, E-mail: jekim@cu.ac.kr [School of Mechanical and Automotive Engineering, Catholic University of Daegu, 13-13 Hayang-Ro, Hayang-Eup, Gyeongsan-Si, Gyeongsangbuk-Do 712-702 (Korea, Republic of)

    2014-10-15

    While environmental vibrations are usually in the range of a few hundred Hertz, small-form-factor piezoelectric vibration energy harvesters will have higher resonant frequencies due to the structural size effect. To address this issue, we propose a resonant frequency-down conversion based on the theory of dynamic vibration absorber for the design of a small-form-factor piezoelectric vibration energy harvester. The proposed energy harvester consists of two frequency-tuned elastic components for lowering the first resonant frequency of an integrated system but is so configured that an energy harvesting beam component is inverted with respect to the other supporting beam component for a small form factor. Furthermore, in order to change the unwanted modal characteristic of small separation of resonant frequencies, as is the case with an inverted configuration, a proof mass on the supporting beam component is slightly shifted toward a second proof mass on the tip of the energy harvesting beam component. The proposed small-form-factor design capability was experimentally verified using a fabricated prototype with an occupation volume of 20 × 39 × 6.9 mm{sup 3}, which was designed for a target frequency of as low as 100 Hz.

  17. A small-form-factor piezoelectric vibration energy harvester using a resonant frequency-down conversion

    Directory of Open Access Journals (Sweden)

    Kyung Ho Sun

    2014-10-01

    Full Text Available While environmental vibrations are usually in the range of a few hundred Hertz, small-form-factor piezoelectric vibration energy harvesters will have higher resonant frequencies due to the structural size effect. To address this issue, we propose a resonant frequency-down conversion based on the theory of dynamic vibration absorber for the design of a small-form-factor piezoelectric vibration energy harvester. The proposed energy harvester consists of two frequency-tuned elastic components for lowering the first resonant frequency of an integrated system but is so configured that an energy harvesting beam component is inverted with respect to the other supporting beam component for a small form factor. Furthermore, in order to change the unwanted modal characteristic of small separation of resonant frequencies, as is the case with an inverted configuration, a proof mass on the supporting beam component is slightly shifted toward a second proof mass on the tip of the energy harvesting beam component. The proposed small-form-factor design capability was experimentally verified using a fabricated prototype with an occupation volume of 20 × 39 × 6.9 mm3, which was designed for a target frequency of as low as 100 Hz.

  18. Ultralong range ICD in the He dimer, resonant Auger - ICD cascade processes

    Energy Technology Data Exchange (ETDEWEB)

    Jahnke, Till [IKF, Goethe Universitaet, Max-von-Laue-Str.1, 60438 Frankfurt am Main (Germany)

    2013-07-01

    Interatomic (or intermolecular) Coulombic Decay (ICD) has become an extensively studied atomic decay process during the last 10 years. The talk shows examples of different systems in which ICD has been examined. In particular helium molecules (so called helium dimers) are presented in which ICD occurs over longest internuclear distances. In ICD electrons of low energy are created as a typical decay product. Such electrons are known to effectively cause DNA double strand breakups suggesting ICD as a possible origin for radiation damage of living tissue. The group of L. Cederbaum recently suggested that ICD can be triggered efficiently and site-selectively by resonant excitation of molecules. They realized that this provides a unique tool to create low energy electrons at a specific site inside a biological system for example in order to damage malignant cells that are tagged using specific marker molecules. Here we show experimentally that resonant Auger induced ICD can indeed be observed in model systems of small nitrogen and carbon monoxide clusters and - as expected - produces low energy electrons. Furthermore our simple model systems are able to prove the efficiency of ICD: it occurs before the individual molecule is able to undergo dissociation, i.e on a timescale <10 fs. Our findings therefore strongly support the idea of resonant Auger-ICD being a promising process to induce radiation damage at a specific site inside a high-Z-tagged cell.

  19. Nano Sensing and Energy Conversion Using Surface Plasmon Resonance (SPR).

    Science.gov (United States)

    Kim, Iltai Isaac; Kihm, Kenneth David

    2015-07-16

    Nanophotonic technique has been attracting much attention in applications of nano-bio-chemical sensing and energy conversion of solar energy harvesting and enhanced energy transfer. One approach for nano-bio-chemical sensing is surface plasmon resonance (SPR) imaging, which can detect the material properties, such as density, ion concentration, temperature, and effective refractive index in high sensitivity, label-free, and real-time under ambient conditions. Recent study shows that SPR can successfully detect the concentration variation of nanofluids during evaporation-induced self-assembly process. Spoof surface plasmon resonance based on multilayer metallo-dielectric hyperbolic metamaterials demonstrate SPR dispersion control, which can be combined with SPR imaging, to characterize high refractive index materials because of its exotic optical properties. Furthermore, nano-biophotonics could enable innovative energy conversion such as the increase of absorption and emission efficiency and the perfect absorption. Localized SPR using metal nanoparticles show highly enhanced absorption in solar energy harvesting. Three-dimensional hyperbolic metamaterial cavity nanostructure shows enhanced spontaneous emission. Recently ultrathin film perfect absorber is demonstrated with the film thickness is as low as ~1/50th of the operating wavelength using epsilon-near-zero (ENZ) phenomena at the wavelength close to SPR. It is expected to provide a breakthrough in sensing and energy conversion applications using the exotic optical properties based on the nanophotonic technique.

  20. Nano Sensing and Energy Conversion Using Surface Plasmon Resonance (SPR

    Directory of Open Access Journals (Sweden)

    Iltai (Isaac Kim

    2015-07-01

    Full Text Available Nanophotonic technique has been attracting much attention in applications of nano-bio-chemical sensing and energy conversion of solar energy harvesting and enhanced energy transfer. One approach for nano-bio-chemical sensing is surface plasmon resonance (SPR imaging, which can detect the material properties, such as density, ion concentration, temperature, and effective refractive index in high sensitivity, label-free, and real-time under ambient conditions. Recent study shows that SPR can successfully detect the concentration variation of nanofluids during evaporation-induced self-assembly process. Spoof surface plasmon resonance based on multilayer metallo-dielectric hyperbolic metamaterials demonstrate SPR dispersion control, which can be combined with SPR imaging, to characterize high refractive index materials because of its exotic optical properties. Furthermore, nano-biophotonics could enable innovative energy conversion such as the increase of absorption and emission efficiency and the perfect absorption. Localized SPR using metal nanoparticles show highly enhanced absorption in solar energy harvesting. Three-dimensional hyperbolic metamaterial cavity nanostructure shows enhanced spontaneous emission. Recently ultrathin film perfect absorber is demonstrated with the film thickness is as low as ~1/50th of the operating wavelength using epsilon-near-zero (ENZ phenomena at the wavelength close to SPR. It is expected to provide a breakthrough in sensing and energy conversion applications using the exotic optical properties based on the nanophotonic technique.

  1. Gravity resonance spectroscopy constrains dark energy and dark matter scenarios.

    Science.gov (United States)

    Jenke, T; Cronenberg, G; Burgdörfer, J; Chizhova, L A; Geltenbort, P; Ivanov, A N; Lauer, T; Lins, T; Rotter, S; Saul, H; Schmidt, U; Abele, H

    2014-04-18

    We report on precision resonance spectroscopy measurements of quantum states of ultracold neutrons confined above the surface of a horizontal mirror by the gravity potential of Earth. Resonant transitions between several of the lowest quantum states are observed for the first time. These measurements demonstrate that Newton's inverse square law of gravity is understood at micron distances on an energy scale of 10-14  eV. At this level of precision, we are able to provide constraints on any possible gravitylike interaction. In particular, a dark energy chameleon field is excluded for values of the coupling constant β>5.8×108 at 95% confidence level (C.L.), and an attractive (repulsive) dark matter axionlike spin-mass coupling is excluded for the coupling strength gsgp>3.7×10-16 (5.3×10-16) at a Yukawa length of λ=20  μm (95% C.L.).

  2. Gravity Resonance Spectroscopy Constrains Dark Energy and Dark Matter Scenarios

    Science.gov (United States)

    Jenke, T.; Cronenberg, G.; Burgdörfer, J.; Chizhova, L. A.; Geltenbort, P.; Ivanov, A. N.; Lauer, T.; Lins, T.; Rotter, S.; Saul, H.; Schmidt, U.; Abele, H.

    2014-04-01

    We report on precision resonance spectroscopy measurements of quantum states of ultracold neutrons confined above the surface of a horizontal mirror by the gravity potential of Earth. Resonant transitions between several of the lowest quantum states are observed for the first time. These measurements demonstrate that Newton's inverse square law of gravity is understood at micron distances on an energy scale of 10-14 eV. At this level of precision, we are able to provide constraints on any possible gravitylike interaction. In particular, a dark energy chameleon field is excluded for values of the coupling constant β >5.8×108 at 95% confidence level (C.L.), and an attractive (repulsive) dark matter axionlike spin-mass coupling is excluded for the coupling strength gsgp>3.7×10-16 (5.3×10-16) at a Yukawa length of λ =20 μm (95% C.L.).

  3. Backward asymmetry measurements in the elastic pion-proton scattering at resonance energies

    OpenAIRE

    Alekseev, I. G.; Bazhanov, N. A.; Beloglazov, Yu. A.; Budkovsky, P. E.; Bunyatova, E. I.; Filimonov, E. A.; Kanavets, V. P.; Kovalev, A. I.; Koroleva, L. I.; Morozov, B. V.; Nesterov, V. M.; Novinsky, D. V.; Ryltsov, V. V.; Shchedrov, V. A.; Sulimov, A. D.

    2008-01-01

    The asymmetry parameter P was measured for the elastic pion-proton scattering in the very backward angular region of theta_cm ~ 150-170^o at several pion beam energies in the invariant mass range containing most of the pion-proton resonances. The general goal of the experimental program was to provide new data for partial wave analyses in order to resolve their uncertainties in the baryon resonance region to allow the unambiguous baryon spectrum reconstructions. Until recently the parameter P...

  4. Resonant energy transfer based biosensor for detection of multivalent proteins.

    Energy Technology Data Exchange (ETDEWEB)

    Song, X. (Xuedong); Swanson, Basil I.

    2001-01-01

    We have developed a new fluorescence-based biosensor for sensitive detection of species involved in a multivslent interaction. The biosensor system utilizes specific interactions between proteins and cell surface receptors, which trigger a receptor aggregation process. Distance-dependent fluorescence self-quenching and resonant energy transfer mechanisms were coupled with a multivalent interaction to probe the receptor aggregation process, providing a sensitive and specific signal transduction method for such a binding event. The fluorescence change induced by the aggregation process can be monitored by different instrument platforms, e.g. fluorimetry and flow cytometry. In this article, a sensitive detection of pentavalent cholera toxin which recognizes ganglioside GM1 has been demonstrated through the resonant energy transfer scheme, which can achieve a double color change simultaneously. A detection sensitivity as high as 10 pM has been achieved within a few minutes (c.a. 5 minutes). The simultaneous double color change (an increase of acceptor fluorescence and a decrease of donor fluorescence intensity) of two similar fluorescent probes provides particularly high detection reliability owing to the fact that they act as each other's internal reference. Any external perturbation such as environmental temperature change causes no significant change in signal generation. Besides the application for biological sensing, the method also provides a useful tool for investigation of kinetics and thermodynamics of a multivalent interaction. Keywords: Biosensor, Fluorescence resonant energy transfer, Multivalent interaction, Cholera Toxin, Ganglioside GM1, Signal Transduction

  5. Introducing novel amorphous carbon nanoparticles as energy acceptors into a chemiluminescence resonance energy transfer immunoassay system.

    Science.gov (United States)

    Wang, Zhenxing; Gao, Hongfei; Fu, Zhifeng

    2013-11-21

    A novel chemiluminescence resonance energy transfer (CRET) system for competitive immunoassay of biomolecules was developed by using novel amorphous carbon nanoparticles (CNPs) prepared from candle soot as energy acceptors. The CNPs were firstly prepared to bind with the antigen (Ag) for obtaining the nanocomposite CNP-Ag, and this obtained CNP-Ag was then reacted with the horseradish peroxidase-labeled antibody (HRP-Ab) to assemble the CRET system. The luminol catalyzed by HRP serving as the energy donor for CNPs triggered the CRET phenomenon between luminol and CNPs, which led to the chemiluminescence signal decrease. Due to the competitive immunoreaction of the target antigen and the CNP-Ag, a part of the CNP-Ag was replaced from the HRP-Ab, and then resulted in a weaker interaction between luminol and CNPs. Thus the competitive immunoreaction led to a higher chemiluminescence emission. This CNP-based CRET system was successfully applied to detect the human IgG as a model analyte, and a linear range of 10-200 ng mL(-1) and a detection limit of 1.9 ng mL(-1) (S/N = 3) were obtained. The results for real sample analysis demonstrated its application potential in some important areas such as clinical diagnosis.

  6. Renewable Energy Opportunities at White Sands Missile Range, New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Chvala, William D.; Solana, Amy E.; States, Jennifer C.; Warwick, William M.; Weimar, Mark R.; Dixon, Douglas R.

    2008-09-01

    The document provides an overview of renewable resource potential at White Sands Missile Range (WSMR) based primarily upon analysis of secondary data sources supplemented with limited on-site evaluations. The effort was funded by the U.S. Army Installation Management Command (IMCOM) as follow-on to the 2005 DoD Renewable Energy Assessment. This effort focuses on grid-connected generation of electricity from renewable energy sources and also ground source heat pumps (GSHPs) for heating and cooling buildings, as directed by IMCOM.

  7. Frustrated resonating valence bond states in two dimensions: classification and short-range correlations.

    Science.gov (United States)

    Yang, Fan; Yao, Hong

    2012-10-05

    Resonating valence bond (RVB) states are of crucial importance in our intuitive understanding of quantum spin liquids in 2D. We systematically classify short-range bosonic RVB states into symmetric or nematic spin liquids by examining their flux patterns. We further map short-range bosonic RVB states into projected BCS wave functions, on which we perform large-scale Monte Carlo simulations without the minus sign problem. Our results clearly show that both spin and dimer correlations decay exponentially in all the short-range frustrated (nonbipartite or Z2) bosonic RVB states we studied, indicating that they are gapped Z2 quantum spin liquids. Generically, we conjecture that all short-range frustrated bosonic RVB states in 2D have only short-range correlations.

  8. Harvesting under transient conditions: harvested energy as a proxy for optimal resonance frequency detuning

    Science.gov (United States)

    Hynds, Taylor D.; Kauffman, Jeffrey L.

    2015-04-01

    Piezoelectric-based vibration energy harvesting is of interest in a wide range of applications, and a number of harvesting schemes have been proposed and studied { primarily when operating under steady state conditions. However, energy harvesting behavior is rarely studied in systems with transient excitations. This paper will work to develop an understanding of this behavior within the context of a particular vibration reduction technique, resonance frequency detuning. Resonance frequency detuning provides a method of reducing mechanical response at structural resonances as the excitation frequency sweeps through a given range. This technique relies on switching the stiffness state of a structure at optimal times to detune its resonance frequency from that of the excitation. This paper examines how this optimal switch may be triggered in terms of the energy harvested, developing a normalized optimal switch energy that is independent of the open- and short-circuit resistances. Here the open- and short-circuit shunt resistances refer to imposed conditions that approximate the open- and short-circuit conditions, via high and low resistance shunts. These conditions are practically necessary to harvest the small amounts of power needed to switch stiffness states, as open-circuit and closed-circuit refer to infinite resistance and zero resistance, respectively, and therefore no energy passes through the harvesting circuit. The limiting stiffness states are then defined by these open- and short-circuit resistances. The optimal switch energy is studied over a range of sweep rates, damping ratios, and coupling coefficients; it is found to increase with the coupling coefficient and decrease as the sweep rate and damping ratio increase, behavior which is intuitive. Higher coupling means more energy is converted by the piezoelectric material, and therefore more energy is harvested in a given time; an increased sweep rate means resonance is reached sooner, and there will less

  9. Energy based correlation criteria in the mid-frequency range

    Science.gov (United States)

    Biedermann, J.; Winter, R.; Wandel, M.; Böswald, M.

    2017-07-01

    Aircraft structures are characterized by their lightweight design. As such, they are prone to vibrations. Numerical models based on the Finite Element Method often show significant deviations when the mid-frequency range is considered, where strong interaction between vibrations and acoustics is present. Model validation based on experimental modal data is often not possible due to the high modal density that aircraft fuselage structures exhibit in this frequency range. Classical correlation criteria like the Modal Assurance Criterion require mode shapes and can therefore not be applied. Other correlation criteria using frequency response data, such as the Frequency Domain Assurance Criterion, are highly sensitive to even small structural modifications and fail to indicated the correlation between test and analysis data in the mid-frequency range. Nevertheless, validated numerical models for the mid- to high-frequency ranges are a prerequisite for acoustic comfort predictions of aircraft cabin. This paper presents a new method for the correlation of response data from test and analysis in the mid-frequency range to support model validation in the mid-frequency range and to enable the usage of finite element models in this frequency range. The method is validated on a stiffened cylindrical shell structure, which represents a scale-model of an aircraft fuselage. The correlation criterion presented here is inspired by Statistical Energy Analysis and is based on kinetic energies integrated over frequency bands and spatially integrated over surface areas of the structure. The objective is to indicate frequency bands where the finite element model needs to be adjusted to better match with experimental observations and to locate the areas where these adjustments should be applied.

  10. Carbon and energy balances for a range of biofuels options

    Energy Technology Data Exchange (ETDEWEB)

    Elsayed, M.A.; Matthews, R.; Mortimer, N.D.

    2003-03-01

    This is the final report of a project to produce a set of baseline energy and carbon balances for a range of electricity, heat and transport fuel production systems based on biomass feedstocks. A list of 18 important biofuel technologies in the UK was selected for study of their energy and carbon balances in a consistent approach. Existing studies on these biofuel options were reviewed and their main features identified in terms of energy input, greenhouse gas emissions (carbon dioxide, methane, nitrous oxide and total), transparency and relevance. Flow charts were produced to represent the key stages of the production of biomass and its conversion to biofuels. Outputs from the study included primary energy input per delivered energy output, carbon dioxide outputs per delivered energy output, methane output per delivered energy output, nitrous oxide output per delivered energy output and total greenhouse gas requirements. The net calorific value of the biofuel is given where relevant. Biofuels studied included: biodiesel from oilseed rape and recycled vegetable oil; combined heat and power (CHP) by combustion of wood chip from forestry residues; CHP by gasification of wood chip from short rotation coppice; electricity from the combustion of miscanthus, straw, wood chip from forestry residues and wood chip from short rotation coppice; electricity from gasification of wood chip from forestry residues and wood chip from short rotation coppice; electricity by pyrolysis of wood chip from forestry residues and wood chip from short rotation coppice; ethanol from lignocellulosics, sugar beet and wheat; heat (small scale) from combustion of wood chip from forestry residues and wood chip from short rotation coppice; and rapeseed oil from oilseed rape.

  11. Quantifying stickiness: thermodynamic characterization of intramolecular domain interactions to guide the design of forster resonance energy transfer sensors

    NARCIS (Netherlands)

    Lindenburg, L.H.; Malisauskas, M.; Sips, T.; Oppen, L.M.P.E. van; Wijnands, S.P.; Graaf, S.F.J. van de; Merkx, M.

    2014-01-01

    The introduction of weak, hydrophobic interactions between fluorescent protein domains (FPs) can substantially increase the dynamic range (DR) of Forster resonance energy transfer (FRET)-based sensor systems. Here we report a comprehensive thermodynamic characterization of the stability of a range

  12. Investing relational energy: the hallmark of resonant leadership.

    Science.gov (United States)

    Cummings, Greta

    2004-11-01

    Recent research has shown that hospital restructuring that included staff layoff has adversely affected the role, health and well-being of nurses who remained employed. Further research found that nurses working in environments that reflected resonant (emotionally intelligent) leadership reported the least negative effects to their healt and well-being following hospital restructuring. What remained unclear was the mechanism by which this mitigation occurred. The purpose of this paper is to explore additional findings from this leadership research and discuss one explanation unique to the academic literature for the mitigation variable--the investment of relational energy by resonant nursing leadership to build relationships with nurses and manage emotion in the workplace.

  13. Integrated optical gyroscope using active long-range surface plasmon-polariton waveguide resonator.

    Science.gov (United States)

    Zhang, Tong; Qian, Guang; Wang, Yang-Yang; Xue, Xiao-Jun; Shan, Feng; Li, Ruo-Zhou; Wu, Jing-Yuan; Zhang, Xiao-Yang

    2014-01-24

    Optical gyroscopes with high sensitivity are important rotation sensors for inertial navigation systems. Here, we present the concept of integrated resonant optical gyroscope constructed by active long-range surface plasmon-polariton (LRSPP) waveguide resonator. In this gyroscope, LRSPP waveguide doped gain medium is pumped to compensate the propagation loss, which has lower pump noise than that of conventional optical waveguide. Peculiar properties of single-polarization of LRSPP waveguide have been found to significantly reduce the polarization error. The metal layer of LRSPP waveguide is electro-optical multiplexed for suppression of reciprocal noises. It shows a limited sensitivity of ~10(-4) deg/h, and a maximum zero drift which is 4 orders of magnitude lower than that constructed by conventional single-mode waveguide.

  14. Comparison and experimental validation of two potential resonant viscosity sensors in the kilohertz range

    Science.gov (United States)

    Lemaire, Etienne; Heinisch, Martin; Caillard, Benjamin; Jakoby, Bernhard; Dufour, Isabelle

    2013-08-01

    Oscillating microstructures are well established and find application in many fields. These include force sensors, e.g. AFM micro-cantilevers or accelerometers based on resonant suspended plates. This contribution presents two vibrating mechanical structures acting as force sensors in liquid media in order to measure hydrodynamic interactions. Rectangular cross section microcantilevers as well as circular cross section wires are investigated. Each structure features specific benefits, which are discussed in detail. Furthermore, their mechanical parameters and their deflection in liquids are characterized. Finally, an inverse analytical model is applied to calculate the complex viscosity near the resonant frequency for both types of structures. With this approach it is possible to determine rheological parameters in the kilohertz range in situ within a few seconds. The monitoring of the complex viscosity of yogurt during the fermentation process is used as a proof of concept to qualify at least one of the two sensors in opaque mixtures.

  15. An optical fiber surface plasmon resonance biosensor for wide range detection

    Science.gov (United States)

    Tong, Kai; Guo, Jia; Wang, Meiyu; Dang, Peng; Wang, Fucheng; Zhang, Yungang; Wang, Meiting

    2017-10-01

    An optical fiber surface plasmon resonance biosensor is presented that allows to numerically demonstrate, using transfer matrix method and the finite difference time domain method, the detection range is very wide. Two different structures of graphene photonic crystal multilayer (i.e. sensor I and sensor II) are constructed in the cladding region of single-mode fiber. Graphene is used as the plasma layer instead of the traditional metal. According to the analysis, the properties of graphene can be changed by adjusting the chemical potential µc. In the spectral region of 1.667|µc| < ћω < 2|µc|, the imaginary part of conductivity σ″ becomes negative. Thus the weakly bounded low-less TE-SPR is supported by graphene. The results of the numerical simulation show that the relationship between refractive index and resonant wavelength is linear. The sensor I can detect the refractive index range of 1.33-1.4, and the sensitivity is 1942 nm/RIU. The sensor II can detect the refractive index range of 1.41-1.67, and the sensitivity is up to 2315.4 nm/RIU. Therefore, the detection of wide refractive index range of 1.33-1.67 or simultaneous detection of different biological medium concentration is realized by the sensor.

  16. Superconducting resonator used as a phase and energy detector for linac setup

    Directory of Open Access Journals (Sweden)

    Nikolai R. Lobanov

    2016-07-01

    Full Text Available Booster linacs for tandem accelerators and positive ion superconducting injectors have matured into standard features of many accelerator laboratories. Both types of linac are formed as an array of independently-phased resonators operating at room temperature or in a superconducting state. Each accelerating resonator needs to be individually set in phase and amplitude for optimum acceleration efficiency. The modularity of the linac allows the velocity profile along the structure to be tailored to accommodate a wide range charge to mass ratio. The linac setup procedure, described in this paper, utilizes a superconducting resonator operating in a beam bunch phase detection mode. The main objective was to derive the full set of phase distributions for quick and efficient tuning of the entire accelerator. The phase detector was operated in overcoupling mode in order to minimize de-tuning effects of microphonic background. A mathematical expression was derived to set a limit on resonator maximum accelerating field during the crossover search to enable extracting unambiguous beam phase data. A set of equations was obtained to calculate the values of beam phase advance and energy gain produced by accelerating resonators. An extensive range of linac setting up configurations was conducted to validate experimental procedures and analytical models. The main application of a superconducting phase detector is for fast tuning for beams of ultralow intensities, in particular in the straight section of linac facilities.

  17. Effect of internal resistance of a Helmholtz resonator on acoustic energy reduction in enclosures.

    Science.gov (United States)

    Yu, Ganghua; Li, Deyu; Cheng, Li

    2008-12-01

    The effect of internal resistance of a Helmholtz resonator on acoustic energy reduction in an enclosure and the multimodal coupling-based Helmholtz resonator design are investigated. Using the analytical solution of a resonator-enclosure interaction model, an energy reduction index is defined in a frequency band to optimize the resonator resistance. The dual process of energy dissipation and radiation of the resonator is quantified. Optimal resistance of the resonator and its physical effect on the resonator-enclosure interaction are numerically evaluated and categorized in terms of frequency bandwidths. Predictions on the resonator performance are confirmed by experiments. Comparisons with existing models based on different optimization criteria are also performed. It is shown that the proposed model serves as an effective design tool to determine the internal resistance of the resonator in order to achieve sound reduction in the frequency band enclosing acoustic resonances.

  18. Ground state potential energy surfaces around selected atoms from resonant inelastic x-ray scattering.

    Science.gov (United States)

    Schreck, Simon; Pietzsch, Annette; Kennedy, Brian; Såthe, Conny; Miedema, Piter S; Techert, Simone; Strocov, Vladimir N; Schmitt, Thorsten; Hennies, Franz; Rubensson, Jan-Erik; Föhlisch, Alexander

    2016-01-29

    Thermally driven chemistry as well as materials' functionality are determined by the potential energy surface of a systems electronic ground state. This makes the potential energy surface a central and powerful concept in physics, chemistry and materials science. However, direct experimental access to the potential energy surface locally around atomic centers and to its long-range structure are lacking. Here we demonstrate how sub-natural linewidth resonant inelastic soft x-ray scattering at vibrational resolution is utilized to determine ground state potential energy surfaces locally and detect long-range changes of the potentials that are driven by local modifications. We show how the general concept is applicable not only to small isolated molecules such as O2 but also to strongly interacting systems such as the hydrogen bond network in liquid water. The weak perturbation to the potential energy surface through hydrogen bonding is observed as a trend towards softening of the ground state potential around the coordinating atom. The instrumental developments in high resolution resonant inelastic soft x-ray scattering are currently accelerating and will enable broad application of the presented approach. With this multidimensional potential energy surfaces that characterize collective phenomena such as (bio)molecular function or high-temperature superconductivity will become accessible in near future.

  19. Design and kinetic analysis of piezoelectric energy harvesters with self-adjusting resonant frequency

    Science.gov (United States)

    Yu-Jen, Wang; Tsung-Yi, Chuang; Jui-Hsin, Yu

    2017-09-01

    Vibration-based energy harvesters have been developed as power sources for wireless sensor networks. Because the vibration frequency of the environment is varied with surrounding conditions, how to design an adaptive energy harvester is a practical topic. This paper proposes a design for a piezoelectric energy harvester possessing the ability to self-adjust its resonant frequency in rotational environments. The effective length of a trapezoidal cantilever is extended by centrifugal force from a rotating wheel to vary its area moment of inertia. The analytical solution for the natural frequency of the piezoelectric energy harvester was derived from the parameter design process, which could specify a structure approaching resonance at any wheel rotating frequency. The kinetic equation and electrical damping induced by power generation were derived from a Lagrange method and a mechanical-electrical coupling model, respectively. An energy harvester with adequate parameters can generate power at a wide range of car speeds. The output power of an experimental prototype composed of piezoelectric thin films and connected to a 3.3 MΩ external resistor was approximately 70-140 μW at wheel speeds ranging from 200 to 700 RPM. These results demonstrate that the proposed piezoelectric energy harvester can be applied as a power source for the wireless tire pressure monitoring sensor.

  20. Comparative Analysis of Resonant Converters for Energy Storage Systems

    Directory of Open Access Journals (Sweden)

    Vuchev Stoyan

    2017-01-01

    Full Text Available The following paperwork presents a comparative analysis of multiphase resonant converters for applications in energy storage systems. Models of the examined converters are developed in the software environments of MATLAB and LTspice. Results from the simulation examination of the converters during charging of supercapacitors and rechargeable batteries are presented. These results are compared to results obtained from experimental examination of the converters via a laboratory stand. For the purposes of the experimental examination, a control system is developed on the base of a virtual instrument in LabVIEW. The advantages and disadvantages of the different converters are discussed.

  1. Large range localized surface plasmon resonance of Ag nanoparticles films dependent of surface morphology

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Lijuan; Yan, Yaning; Xu, Leilei; Ma, Rongrong; Jiang, Fengxian; Xu, Xiaohong, E-mail: xuxh@dns.sxnu.edu.cn

    2016-03-30

    Graphical abstract: - Highlights: • Large range tuned localized surface plasmon resonance of Ag nanoparticles films. • The noble metal Ag has the strongest localized surface plasmon resonance and low optical loss. Besides, it is the cheaper than other noble metal. • The nanoparticles films fabricated using physical methods have the stronger interaction with substrates than chemical methods, which are not easy exfoliation. - Abstract: Noble metal nanoparticles (NPs) have received enormous attention since it displays uniquely optical and electronic properties. In this work, we study localized surface plasmon resonances (LSPR) at different thicknesses and substrate temperatures of Ag NPs films grown by Laser Molecule Beam Epitaxy (LMBE). The LSPR wavelength can be largely tuned in the visible light range of 470 nm to 770 nm. The surface morphology is characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The average size of Ag NPs increased with the thickness increased which leading to the LSPR band broaden and wavelength red-shift. As the substrate temperature is increased from RT to 200 °C, the Ag NPs size distribution becomes homogeneous and particle shape changes from oblate spheroid to sphere, the LSPR band displays sharp, blue-shift and significantly symmetric. Obviously, the morphology of Ag NPs films is important for tuning absorption position. We obtain the cubic crystal structure of Ag NPs with a (1 1 1) main diffraction peak from the X-ray diffraction (XRD) spectra. The high resolution TEM (HR-TEM) and selected area electron diffraction (SAED) prove that Ag NPs is polycrystal structure. The Ag NPs films with large range absorption in visible light region can composite with semiconductor to apply in various optical or photoelectric devices.

  2. High energy resolution off-resonant spectroscopy: A review

    Science.gov (United States)

    Błachucki, Wojciech; Hoszowska, Joanna; Dousse, Jean-Claude; Kayser, Yves; Stachura, Regina; Tyrała, Krzysztof; Wojtaszek, Klaudia; Sá, Jacinto; Szlachetko, Jakub

    2017-10-01

    We review the high energy resolution off-resonant spectroscopy (HEROS) technique. HEROS probes the unoccupied electronic states of matter in a single-shot manner thanks to the combination of off-resonant excitation around atomic core states using wavelength dispersive X-ray detection setups. In this review we provide a general introduction to the field of X-ray spectroscopy together with the specification of the available X-ray techniques and X-ray methodologies. Next, the theoretical description of the HEROS approach is introduced with a special focus on the derivation of the X-ray emission and X-ray absorption correspondence relation at off-resonant excitation conditions. Finally, a number of experimental HEROS reports are reviewed in the field of chemistry and material science. We emphasize the applicability of HEROS to pulsed X-ray sources, like X-ray free electron lasers, and support the review with experimental examples. The review is complemented with perspectives on and possible further applications of the HEROS technique to the field of X-ray science.

  3. Range, energy loss, energy straggling and damage production for [alpha]-particles in uranium dioxide

    Science.gov (United States)

    Matzke, Hj.

    Energy loss and energy straggling of α-particles in UO 2 were measured for α-energies up to 8.78 MeV. α-sources of Pu-239 and a `multi-energy source' emitting α-particles of five different energies obtained by recoil implantation from a Th-228 source were coated with UO 2 layers of 17 different thicknesses. Confirmation of these results was obtained from Rutherford backscattering spectroscopy, RBS/channeling experiments with UO 2 single crystals preimplanted with He-ions. The measured energy loss values were used to deduce the range-energy relation. The results are in good agreement with calculations using the code TRIM 96. The energy straggling results are discussed in the frame of Bohr's theory. Finally, defects and damage produced by α-particles and He-ions in UO 2 are briefly treated.

  4. Non-Resonant Magnetoelectric Energy Harvesting Utilizing Phase Transformation in Relaxor Ferroelectric Single Crystals

    Directory of Open Access Journals (Sweden)

    Peter Finkel

    2015-12-01

    Full Text Available Recent advances in phase transition transduction enabled the design of a non-resonant broadband mechanical energy harvester that is capable of delivering an energy density per cycle up to two orders of magnitude larger than resonant cantilever piezoelectric type generators. This was achieved in a [011] oriented and poled domain engineered relaxor ferroelectric single crystal, mechanically biased to a state just below the ferroelectric rhombohedral (FR-ferroelectric orthorhombic (FO phase transformation. Therefore, a small variation in an input parameter, e.g., electrical, mechanical, or thermal will generate a large output due to the significant polarization change associated with the transition. This idea was extended in the present work to design a non-resonant, multi-domain magnetoelectric composite hybrid harvester comprised of highly magnetostrictive alloy, [Fe81.4Ga18.6 (Galfenol or TbxDy1-xFe2 (Terfenol-D], and lead indium niobate–lead magnesium niobate–lead titanate (PIN-PMN-PT domain engineered relaxor ferroelectric single crystal. A small magnetic field applied to the coupled device causes the magnetostrictive element to expand, and the resulting stress forces the phase change in the relaxor ferroelectric single crystal. We have demonstrated high energy conversion in this magnetoelectric device by triggering the FR-FO transition in the single crystal by a small ac magnetic field in a broad frequency range that is important for multi-domain hybrid energy harvesting devices.

  5. Resonant tunneling: A method for simultaneous determination of resonance energy and energy eigenvalue

    Energy Technology Data Exchange (ETDEWEB)

    Maiz, F., E-mail: Fethi_maiz@yahoo.fr [King Khalid University, Faculty of Science, Physics Department, P.O. Box 9004, Abha (Saudi Arabia); University of Cartage, Nabeul Engineering Preparatory Institute, Merazka, 8000 Nabeul (Tunisia); Eissa, S.A. [King Khalid University, Faculty of Science, Physics Department, P.O. Box 9004, Abha (Saudi Arabia); AL-AZHAR University, Faculty of Science, Physics Department, Nasr City, Cairo (Egypt); AlFaify, S. [King Khalid University, Faculty of Science, Physics Department, P.O. Box 9004, Abha (Saudi Arabia)

    2013-09-15

    Assuming an effective mass approximation and using Bastard's boundary conditions, a simple method for simultaneous determination of the energy levels forming the sub-band structure and the transmissions coefficient of non-symmetrical, non-periodical potential semiconducting heterostructure is being proposed. The method can be applied on a multilayer system with varying thickness and effective mass of the layers, and with potential that is neither periodical nor symmetrical. To illustrate the feasibility of the proposed method, cases of symmetrical rectangular triple-barrier structure with constant effective mass, multi-barrier semiconductor heterostructure (nine barriers–eight-wells), and monomer height barrier superlattices (300 barriers) systems have been examined. Findings show very good agreements with previously published results obtained by different methods on similar systems. The proposed method was found to be useful for any number of semiconducting layers arranged in any random way making it more realistic, simple, and applicable to superlattice analysis and for devices design.

  6. Short-range resonating-valence-bond state of even-spin ladders: A recurrent variational approach

    Science.gov (United States)

    Sierra, Germán; Martín-Delgado, Miguel A.

    1997-10-01

    Using a recursive method we construct dimer and nondimer variational ansatzs of the ground state for the two-legged ladder, and compute the number of dimer coverings, the energy density, and the spin-correlation functions. The number of dimer coverings are given by the Fibonacci numbers for the dimer-resonating-valence-bond state and their generalization for the nondimer states. Our method relies on the recurrent relations satisfied by the overlaps of the states with different lengths, which can be solved using generating functions. The recurrent-relation method is applicable to other short-range systems. Based on our results we make a conjecture about the bond amplitudes of the two-legged ladder.

  7. A current drive by using the fast wave in frequency range higher than two timeslower hybrid resonance frequency on tokamaks

    Directory of Open Access Journals (Sweden)

    Kim Sun Ho

    2017-01-01

    Full Text Available An efficient current drive scheme in central or off-axis region is required for the steady state operation of tokamak fusion reactors. The current drive by using the fast wave in frequency range higher than two times lower hybrid resonance (w>2wlh could be such a scheme in high density, high temperature reactor-grade tokamak plasmas. First, it has relatively higher parallel electric field to the magnetic field favorable to the current generation, compared to fast waves in other frequency range. Second, it can deeply penetrate into high density plasmas compared to the slow wave in the same frequency range. Third, parasitic coupling to the slow wave can contribute also to the current drive avoiding parametric instability, thermal mode conversion and ion heating occured in the frequency range w<2wlh. In this study, the propagation boundary, accessibility, and the energy flow of the fast wave are given via cold dispersion relation and group velocity. The power absorption and current drive efficiency are discussed qualitatively through the hot dispersion relation and the polarization. Finally, those characteristics are confirmed with ray tracing code GENRAY for the KSTAR plasmas.

  8. A Proportional Resonant Control Strategy for Efficiency Improvement in Extended Range Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Xiaoyuan Wang

    2017-02-01

    Full Text Available The key to control the range extender generation system is to improve the efficiency and reduce the emissions of the electric vehicle (EV. In this paper, based on the purpose of efficiency optimization, both engine and generator are matched to get a public high efficiency region, and a partial power following control strategy was presented. The engine speed is constant in the defined power range, so the output power regulation of the range extender is only realized by the adjustment of the torque of the generator. Engine speed and generator torque were decoupled. An improved proportional resonant (PR controller is adopted to achieve fast output power regulation. In order to ensure the response characteristics of the control system and to improve the robustness, the impacts on system’s characteristics and stability caused by PR controller and parameters in the inner-current loop were analyzed via frequency response characteristics. A pre-Tustin with deviation compensation is proposed for PR controller’s discretization. A stable and robust power following control method is obtained for the range extender control system. Finally, simulation and experiment of the proposed control strategy illustrated its feasibility and correctness.

  9. Rapid Detection of Enterotoxigenic Clostridium perfringens by Real-Time Fluorescence Resonance Energy Transfer PCR

    National Research Council Canada - National Science Library

    dela Cruz, Wilfred P; Gozum, Mary M.A; Lineberry, Sarah F; Stassen, Sarah D; Daughtry, Marianne; Stassen, Nicholas A; Jones, Morris S; Johnson, Oswald L

    2006-01-01

    ...) produced by some strains during sporulation. We developed a quantitative real-time PCR assay based on fluorescence resonance energy transfer hybridization chemistry that targets the C. perfringens...

  10. Study of some properties of 's' neutron resonance parameters for target nuclei I = 1/2 and I = 3/2 in function of spin value J = I + 1/2 in the energy range 1 {yields} 5000 eV; Etude de quelques proprietes des parametres de resonances des neutrons ''s'' pour des noyaux cibles I = 1/2 et I = 3/2 en fonction de la valeur du spin J = I + 1/2 dans le domaine d'energie 1 eV {yields} 5000 eV

    Energy Technology Data Exchange (ETDEWEB)

    Julien, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1967-05-15

    Different kinds of experiments and analysis methods allowing to achieve neutron resonances parameters in the low energy range (1 eV {yields} 5000 eV) are described. A great deal of effort to improve experimental conditions and data processing in order to know the spin value J = I {+-} 1/2 has been spent. The time of flight method was used. A few target nuclei I = 3/2 and 1 = 1/2 have been studied. For I = 3/2 (Ga, As, 3r, Au) we find S{sub o} J = 2 {approx_equal} 2 S{sub o} J = 1 and S{sub o} J = 1 {approx_equal} S{sub o} J = 0 for I = 1/2 (Tm, Pt) but {sup 77}Se. Fluctuations of the total radiative width {gamma}{sub {gamma}} depend on the spin value I = I {+-} 1/2 when E1 transition, are enhanced for one of the both spin states. The magnitude of these fluctuations can be explained of the strength of E1 transitions (E{sub {gamma}} {approx} 7 MeV) is supposed to be proportional to E{sup 5}{sub {gamma}} instead of E{sup 3}{sub {gamma}}. The distribution of levels spacings against spin value J are considered and are compared to theoretical predictions. (author) [French] On decrit les differentes methodes d'analyse permettant d'obtenir les parametres des resonances de neutron dans le domaine d'energie 1 eV {yields} 5000 eV. Un effort particulier a ete fait pour connaitre la valeur du spin J = I {+-} 1/2. Les types d'experience et les analyses des donnees, developpes et ameliores pour determiner J sont decrits. Les resultats obtenus ont permis l'etude de differentes proprietes en fonction du spin J. On trouve: S{sub o} J 2 {approx_equal} 2 S{sub o} J = 1 pour les noyaux I = 3/2 etudies (Ga, As, Br, Au) et S{sub o} J = 1 {approx_equal} S{sub o} J = 0 Pour le Tm et {sup 195}Pt de spin I = 1/2. On constate que les largeurs radiatives totales {gamma}{sub {gamma}} fluctuent si des transitions E1 aux premiers etats excites sont favorisees. Ces fluctuations peuvent etre expliquees si on suppose que les intensites de ces transitions sont

  11. Organic solar cells: understanding the role of Förster resonance energy transfer.

    Science.gov (United States)

    Feron, Krishna; Belcher, Warwick J; Fell, Christopher J; Dastoor, Paul C

    2012-12-12

    Organic solar cells have the potential to become a low-cost sustainable energy source. Understanding the photoconversion mechanism is key to the design of efficient organic solar cells. In this review, we discuss the processes involved in the photo-electron conversion mechanism, which may be subdivided into exciton harvesting, exciton transport, exciton dissociation, charge transport and extraction stages. In particular, we focus on the role of energy transfer as described by F¨orster resonance energy transfer (FRET) theory in the photoconversion mechanism. FRET plays a major role in exciton transport, harvesting and dissociation. The spectral absorption range of organic solar cells may be extended using sensitizers that efficiently transfer absorbed energy to the photoactive materials. The limitations of F¨orster theory to accurately calculate energy transfer rates are discussed. Energy transfer is the first step of an efficient two-step exciton dissociation process and may also be used to preferentially transport excitons to the heterointerface, where efficient exciton dissociation may occur. However, FRET also competes with charge transfer at the heterointerface turning it in a potential loss mechanism. An energy cascade comprising both energy transfer and charge transfer may aid in separating charges and is briefly discussed. Considering the extent to which the photo-electron conversion efficiency is governed by energy transfer, optimisation of this process offers the prospect of improved organic photovoltaic performance and thus aids in realising the potential of organic solar cells.

  12. Organic Solar Cells: Understanding the Role of Förster Resonance Energy Transfer

    Science.gov (United States)

    Feron, Krishna; Belcher, Warwick J.; Fell, Christopher J.; Dastoor, Paul C.

    2012-01-01

    Organic solar cells have the potential to become a low-cost sustainable energy source. Understanding the photoconversion mechanism is key to the design of efficient organic solar cells. In this review, we discuss the processes involved in the photo-electron conversion mechanism, which may be subdivided into exciton harvesting, exciton transport, exciton dissociation, charge transport and extraction stages. In particular, we focus on the role of energy transfer as described by Förster resonance energy transfer (FRET) theory in the photoconversion mechanism. FRET plays a major role in exciton transport, harvesting and dissociation. The spectral absorption range of organic solar cells may be extended using sensitizers that efficiently transfer absorbed energy to the photoactive materials. The limitations of Förster theory to accurately calculate energy transfer rates are discussed. Energy transfer is the first step of an efficient two-step exciton dissociation process and may also be used to preferentially transport excitons to the heterointerface, where efficient exciton dissociation may occur. However, FRET also competes with charge transfer at the heterointerface turning it in a potential loss mechanism. An energy cascade comprising both energy transfer and charge transfer may aid in separating charges and is briefly discussed. Considering the extent to which the photo-electron conversion efficiency is governed by energy transfer, optimisation of this process offers the prospect of improved organic photovoltaic performance and thus aids in realising the potential of organic solar cells. PMID:23235328

  13. Organic Solar Cells: Understanding the Role of Förster Resonance Energy Transfer

    Directory of Open Access Journals (Sweden)

    Paul C. Dastoor

    2012-12-01

    Full Text Available Organic solar cells have the potential to become a low-cost sustainable energy source. Understanding the photoconversion mechanism is key to the design of efficient organic solar cells. In this review, we discuss the processes involved in the photo-electron conversion mechanism, which may be subdivided into exciton harvesting, exciton transport, exciton dissociation, charge transport and extraction stages. In particular, we focus on the role of energy transfer as described by F¨orster resonance energy transfer (FRET theory in the photoconversion mechanism. FRET plays a major role in exciton transport, harvesting and dissociation. The spectral absorption range of organic solar cells may be extended using sensitizers that efficiently transfer absorbed energy to the photoactive materials. The limitations of F¨orster theory to accurately calculate energy transfer rates are discussed. Energy transfer is the first step of an efficient two-step exciton dissociation process and may also be used to preferentially transport excitons to the heterointerface, where efficient exciton dissociation may occur. However, FRET also competes with charge transfer at the heterointerface turning it in a potential loss mechanism. An energy cascade comprising both energy transfer and charge transfer may aid in separating charges and is briefly discussed. Considering the extent to which the photo-electron conversion efficiency is governed by energy transfer, optimisation of this process offers the prospect of improved organic photovoltaic performance and thus aids in realising the potential of organic solar cells.

  14. Active Source Management to Maintain High Efficiency in Resonant Conversion over Wide  Load Range

    OpenAIRE

    Danilovic, Milisav

    2015-01-01

    High-frequency and large amplitude current is a driving requirement for applications such as induction heating, wireless power transfer, power amplifier for magnetic resonant imaging, electronic ballasts, and ozone generators. Voltage-fed resonant inverters are normally employed, however, current-fed (CF) resonant inverters are a competitive alternative when the quality factor of the load is significantly high. The input current of a CF resonant inverter is considerably smaller than the outpu...

  15. Backward asymmetry measurements in the elastic pion-proton scattering at resonance energies

    Energy Technology Data Exchange (ETDEWEB)

    Alekseev, I.G.; Budkovsky, P.E.; Kanavets, V.P.; Koroleva, L.I.; Morozov, B.V.; Nesterov, V.M.; Ryltsov, V.V.; Sulimov, A.D.; Svirida, D.N. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Bazhanov, N.A.; Bunyatova, E.I.; Zolin, L.S. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Beloglazov, Yu.A.; Filimonov, E.A.; Kovalev, A.I.; Novinsky, D.V.; Shchedrov, V.A.; Sumachev, V.V.; Trautman, V.Yu. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation)

    2009-02-15

    The asymmetry parameter P was measured for the elastic pion-proton scattering in the very backward angular region of {theta}{sub CM}{approx}150-170 at several pion beam energies in the invariant-mass range containing most of the pion-proton resonances. The general goal of the experimental program was to provide new data for partial wave analyses in order to resolve their uncertainties in the baryon resonance region to allow the unambiguous baryon spectrum reconstructions. Until recently the parameter P was not measured in the examined domain that might be explained by the extremely low cross-section. At the same time the predictions of various partial wave analyses are far from agreement in some kinematic areas and specifically those areas were chosen for the measurements where the disagreement is most pronouncing. The experiment was performed at the ITEP U-10 proton synchrotron, Moscow, by the ITEP-PNPI Collaboration in the latest 5 years. (orig.)

  16. Backward asymmetry measurements in the elastic pion-proton scattering at resonance energies

    Science.gov (United States)

    Alekseev, I. G.; Bazhanov, N. A.; Beloglazov, Yu. A.; Budkovsky, P. E.; Bunyatova, E. I.; Filimonov, E. A.; Kanavets, V. P.; Kovalev, A. I.; Koroleva, L. I.; Morozov, B. V.; Nesterov, V. M.; Novinsky, D. V.; Ryltsov, V. V.; Shchedrov, V. A.; Sulimov, A. D.; Sumachev, V. V.; Svirida, D. N.; Trautman, V. Yu.; Zolin, L. S.

    2009-02-01

    The asymmetry parameter P was measured for the elastic pion-proton scattering in the very backward angular region of θ_{CM}^{} ≈ 150 - 170° at several pion beam energies in the invariant-mass range containing most of the pion-proton resonances. The general goal of the experimental program was to provide new data for partial wave analyses in order to resolve their uncertainties in the baryon resonance region to allow the unambiguous baryon spectrum reconstructions. Until recently the parameter P was not measured in the examined domain that might be explained by the extremely low cross-section. At the same time the predictions of various partial wave analyses are far from agreement in some kinematic areas and specifically those areas were chosen for the measurements where the disagreement is most pronouncing. The experiment was performed at the ITEP U-10 proton synchrotron, Moscow, by the ITEP-PNPI Collaboration in the latest 5 years.

  17. Study of low-energy resonant metastability exchange in argon by a pulsed merging beam technique

    Energy Technology Data Exchange (ETDEWEB)

    Grucker, J [Laboratoire de Physique des Lasers (UMR-CNRS 7538), Universite Paris 13, Av. J.B. Clement, 93430-Villetaneuse (France); Baudon, J [Laboratoire de Physique des Lasers (UMR-CNRS 7538), Universite Paris 13, Av. J.B. Clement, 93430-Villetaneuse (France); Perales, F [Laboratoire de Physique des Lasers (UMR-CNRS 7538), Universite Paris 13, Av. J.B. Clement, 93430-Villetaneuse (France); Dutier, G [Laboratoire de Physique des Lasers (UMR-CNRS 7538), Universite Paris 13, Av. J.B. Clement, 93430-Villetaneuse (France); Vassilev, G [Laboratoire de Physique des Lasers (UMR-CNRS 7538), Universite Paris 13, Av. J.B. Clement, 93430-Villetaneuse (France); Bocvarski, V [Institute of Physics, Belgrade, Pregrevica 118, 11080, Zemun (Serbia); Ducloy, M [Laboratoire de Physique des Lasers (UMR-CNRS 7538), Universite Paris 13, Av. J.B. Clement, 93430-Villetaneuse (France)

    2008-01-28

    The resonant metastability exchange process in low-energy collinear collisions between metastable argon atoms (Ar* {sup 3}P{sub 2}) polarized in spin (M +2) and ground-state Ar atoms from a nozzle beam is studied by means of a time-of-flight technique. A wide range of metastable atom velocities in the laboratory frame (275 m s{sup -1} down to 50 m s{sup -1}) is obtained by use of a Zeeman slower, the counter-propagating laser beam of which is locked in frequency onto the {sup 3}P{sub 2}-{sup 3}D{sub 3} closed transition ({lambda} = 811.5 nm). The accessible centre-of-mass energy range (8-27 meV) has not been explored so far, to our knowledge. Calculations based upon existing interatomic potentials of 2{sub g} and 2{sub u} symmetries are in reasonable agreement with experiment. (fast track communication)

  18. High-energy tail distributions and resonant wave particle interaction

    Science.gov (United States)

    Leubner, M. P.

    1983-01-01

    High-energy tail distributions (k distributions) are used as an alternative to a bi-Lorentzian distribution to study the influence of energetic protons on the right- and left-hand cyclotron modes in a hot two-temperature plasma. Although the parameters are chosen to be in a range appropriate to solar wind or magnetospheric configurations, the results apply not only to specific space plasmas. The presence of energetic particles significantly alters the behavior of the electromagnetic ion cyclotron modes, leading to a wide range of unstable frequencies and increased growth rates. From the strongly enhanced growth rates it can be concluded that high-energy tail distributions should not show major temperature anisotropies, which is consistent with observations.

  19. Nanofabrication of planar split ring resonators for negative refractive index metamaterials in the infrared range

    Directory of Open Access Journals (Sweden)

    ZORAN JAKSIC

    2006-06-01

    Full Text Available Experimental nanofabrication of planar structures for one-dimensional metamaterials designed to achieve a negative effective refractive index in the mid-infrared range (5–10 micrometers was performed. Double split ring and complementary double split ring resonators (SRR and CSRR with square and circular geometries, were chosen to be fabricated since these are the basic building blocks to achieve a negative effective dielectric permittivity and magnetic permeability. Scanning probe nanolithography with z-scanner movement was used to fabricate straight-line and curvilinear segments with a line width of 80 – 120 nm. The geometries were delineated in 20 nm thin silver layers sputter-deposited on a positive photoresist substrate spin-coated on polished single crystal silicon wafers, as well as on polycarbonate slabs. The morphology of the structures was characterized by atomic force microscopy. The feature repeatibility was 60 – 150 nm, depending on the process conditions and the feature complexity. The nanolithographic groove depth in different samples ranged from 4 nm to 80 nm.

  20. Multi-port isolated LLC resonant converter for distributed energy generation with energy storage

    DEFF Research Database (Denmark)

    Tomas Manez, Kevin; Zhang, Zhe; Ouyang, Ziwei

    2017-01-01

    Distributed energy generation systems with energy storage and microgrids have attracted increasing research interest in recent years. Therefore, multi-ports dc-dc converters have gained more interest. However, when integrating into multiple port converters, the power flow control and ports...... regulation increase in complexity. In this paper, an isolated multi-port bidirectional converter based on an LLC converter is presented. The converter operates as a dc transformer at a fixed switching frequency and duty cycle without any control loop. The resonant tanks are designed to ensure soft...

  1. Förster Resonance Energy Transfer between Core/Shell Quantum Dots and Bacteriorhodopsin

    Directory of Open Access Journals (Sweden)

    Mark H. Griep

    2012-01-01

    Full Text Available An energy transfer relationship between core-shell CdSe/ZnS quantum dots (QDs and the optical protein bacteriorhodopsin (bR is shown, demonstrating a distance-dependent energy transfer with 88.2% and 51.1% of the QD energy being transferred to the bR monomer at separation distances of 3.5 nm and 8.5 nm, respectively. Fluorescence lifetime measurements isolate nonradiative energy transfer, other than optical absorptive mechanisms, with the effective QD excited state lifetime reducing from 18.0 ns to 13.3 ns with bR integration, demonstrating the Förster resonance energy transfer contributes to 26.1% of the transferred QD energy at the 3.5 nm separation distance. The established direct energy transfer mechanism holds the potential to enhance the bR spectral range and sensitivity of energies that the protein can utilize, increasing its subsequent photocurrent generation, a significant potential expansion of the applicability of bR in solar cell, biosensing, biocomputing, optoelectronic, and imaging technologies.

  2. Hybrid detection of target sequence DNA based on phosphorescence resonance energy transfer.

    Science.gov (United States)

    Miao, Yanming; Lv, Jinzhi; Yan, Guiqin

    2017-08-15

    The severe background fluorescence and scattering light of real biological samples or environmental samples largely reduce the sensitivity and accuracy of fluorescence resonance energy transfer sensors based on fluorescent quantum dots (QDs). To solve this problem, we designed a novel target sequence DNA biosensor based on phosphorescent resonance energy transfer (PRET). This sensor relied on Mn-doped ZnS (Mn-ZnS) room-temperature phosphorescence (RTP) QDs/poly-(diallyldimethylammonium chloride) (PDADMAC) nanocomposite (QDs+) as the energy donor and the single-strand DNA-ROX as the energy receptor. Thereby, an RTP biosensor was built and used to quantitatively detect target sequence DNA. This biosensor had a detection limit of 0.16nM and a linear range of 0.5-20nM for target sequence DNA. The dependence on RTP of QDs effectively avoided the interference from background fluorescence and scattering light in biological samples. Moreover, this sensor did not need sample pretreatment. Thus, this sensor compared with FRET is more feasible for quantitative detection of target sequence DNA in biological samples. Interestingly, the QDs+ nanocomposite prolonged the phosphorescence lifetime of Mn-ZnS QDs by 2.6 times to 4.94ms, which was 5-6 magnitude-order larger than that of fluorescent QDs. Thus, this sensor largely improves the optical properties of QDs and permits chemical reactions at a long enough time scale. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Effectiveness Testing of a Piezoelectric Energy Harvester for an Automobile Wheel Using Stochastic Resonance

    National Research Council Canada - National Science Library

    Zhang, Yunshun; Zheng, Rencheng; Shimono, Keisuke; Kaizuka, Tsutomu; Nakano, Kimihiko

    2016-01-01

    .... For the case of wheel rotation, the present study investigates the effectiveness of a piezoelectric energy harvester, with the application of stochastic resonance to optimize the efficiency of energy harvesting...

  4. Wide Temperature Range Hybrid Energy Storage Device Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal concerns the fabrication of a hybrid battery capacitor (HBC) using Eltron's knowledge gained in battery and capacitor research. Energy storage systems...

  5. Resonant inelastic scattering at intermediate X-ray energies

    CERN Document Server

    Hague, C F; Journel, L; Gallet, J J; Rogalev, A; Krill, G; Kappler, J P

    2000-01-01

    We describe resonant inelastic X-ray scattering (RIXS) experiments and magnetic circular dichroism (MCD) in X-ray fluorescence performed in the 3-5 keV range. The examples chosen are X-ray fluorescence MCD of FeRh and RIXS experiments performed at the L/sub 3/ edge of Ce. Fe Rh is antiferromagnetic at room temperature but has a transition to the ferromagnetic state above 400 K. The Rh MCD signal is compared with an augmented spherical wave calculation. The experiment confirms the predicted spin polarization of the Rh 4d valence states. The RIXS measurements on Ce compounds and intermetallics address the problem of mixed valency especially in systems where degeneracy with the Fermi level remains small. Examples are taken from the 2p to (4f5d) /sup +1/ followed by 3d to 2p RIXS for a highly ionic compound CeF /sub 3/ and for almost gamma -like CeCuSi. (38 refs).

  6. Measurements of the Complex Permittivity of Liquid Helium-4 in the Millimeter Wave Range by a Whispering Gallery Mode Resonator

    Science.gov (United States)

    Smorodin, A. V.; Rybalko, A. S.; Konstantinov, D.

    2017-06-01

    We report an experimental study of the electrical properties of liquid helium-4 in the temperature range 1.2-3 K. The experiment is carried out in the millimeter wave range using a whispering gallery mode dielectric resonator, and the complex permittivity of liquid helium is extracted from the data using the resonant perturbation method. The results for the temperature dependence of the dielectric constant are consistent with the previous studies. In addition, we find strong enhancement of the loss tangent around the superfluid transition temperature.

  7. Autonomous Vehicles Have a Wide Range of Possible Energy Impacts

    Energy Technology Data Exchange (ETDEWEB)

    Austin Brown, Brittany Repac, Jeff Gonder

    2013-07-15

    Self-driving or “autonomous” vehicles (AVs) have leapt from science fiction into the forefront of transportation technology news. The technology is likely still years away from widespread commercial adoption, but the recent progress makes it worth considering the potential national impacts of widespread implementation. This poster makes an initial assessment of the energy impacts of AV adoptionon a per-vehicle basis and on total personal vehicle fuel use. While AVs offer numerous potential advantages in energy use, there are significant factors that could decrease or even eliminate the energy benefits under some circumstances. This analysis attempts to describe, quantify, and combine many of the possible effects. The nature and magnitude of these effects remain highly uncertain. This set of effects is very unlikely to be exhaustive, but this analysis approach can serve as a base for future estimates.

  8. Application of Long-Range Surface Plasmon Resonance for ABO Blood Typing

    Directory of Open Access Journals (Sweden)

    Wanida Tangkawsakul

    2016-01-01

    Full Text Available In this study, we demonstrate a long-range surface plasmon resonance (LR-SPR biosensor for the detection of whole cell by captured antigens A and B on the surface of red blood cells (RBCs as a model. The LR-SPR sensor chip consists of high-refractive index glass, a Cytop film layer, and a thin gold (Au film, which makes the evanescent field intensity and the penetration depth longer than conventional SPR. Therefore, the LR-SPR biosensor has improved capability for detecting large analytes, such as RBCs. The antibodies specific to blood group A and group B (Anti-A and Anti-B are covalently immobilized on a grafting self-assembled monolayer (SAM/Au surface on the biosensor. For blood typing, RBC samples can be detected by the LR-SPR biosensor through a change in the refractive index. We determined that the results of blood typing using the LR-SPR biosensor are consistent with the results obtained from the agglutination test. We obtained the lowest detection limits of 1.58 × 105 cells/ml for RBC-A and 3.83 × 105 cells/ml for RBC-B, indicating that the LR-SPR chip has a higher sensitivity than conventional SPR biosensors (3.3 × 108 cells/ml. The surface of the biosensor can be efficiently regenerated using 20 mM NaOH. In summary, as the LR-SPR technique is sensitive and has a simple experimental setup, it can easily be applied for ABO blood group typing.

  9. Local energy decay for wave equation in the absence of resonance at zero energy in 3D

    OpenAIRE

    Georgiev, Vladimir; Tarulli, Mirko

    2011-01-01

    In this paper we study spectral properties associated to Schrodinger operator with potential that is an exponential decaying function. As applications we prove local energy decay for solutions to the perturbed wave equation and lack of resonances for the NLS.

  10. Quantitative nuclear magnetic resonance characterization of long-range chain dynamics: Polybutadiene, polyethylene-oxide solution

    Science.gov (United States)

    Guillermo, Armel; Cohen Addad, Jean-Pierre

    2002-02-01

    We report two sets of independent nuclear magnetic resonance (NMR) measurements of self-diffusion and proton transverse relaxation in molten cis1,4-polybutadiene (PB) performed in order to investigate chain dynamics properties. Self-diffusion coefficients were measured as a function of temperature and of molecular weight (M) over the range 104 to 6.7×104g/mol. The crossover from the Rouse-type behavior (D≈M-1) to the reptation one was found to occur for MCross≈3×104g/mol; for M>MCross the data were consistent with the scaling dependence: D≈M-2.4±0.05, in agreement with the data analysis recently reported in the literature. The thorough analysis of the transverse relaxation of protons attached to highly entangled PB chains (6.7×104⩽M⩽43×104g/mol) gave evidence for the dynamics partition of one chain into two end-submolecules and one inner part clearly discriminated from one another. The number NEnd of monomeric units in one end-submolecule, independent of M, is shown to be closely related to the monomeric friction coefficient ζ0 measured from short chain diffusion over the temperature range 25 to 85 °C. The interpretation both of diffusion results and of proton relaxation of inner monomeric units lead to the definition of an effective friction coefficient ζ0Eff≈ζ0(M/NEnd)0.4 associated with the curvilinear diffusion of one chain in its tube. The friction coefficient ζLoc associated with local monomeric rotations is discriminated from ζ0 from its weaker temperature dependence. This approach was applied to polyethylene-oxide chains in solution (dimethyl formamide, 0.18⩽c⩽1, w/w) where the segmental size of end-submolecules was found to vary as 1/c. Experimental results are well matched by this specific NMR approach which accounts for the novel properties of the proton relaxation function.

  11. Increased fuel standards among broad range of energy options

    Science.gov (United States)

    Showstack, Randy

    During simpler times, the mention of the word 'cafe' might have primarily conjured up images of sidewalk coffee and tea bars along Paris' Champs-Elysees. However, with today's concerns about energy needs, CAFE or Corporate Average Fuel Economy standards for automobile fuel efficiency is a hot topic.On August 2, the U.S. House of Representa tives passed an energy bill rejecting a proposal to substantially increase CAFE standards for increasingly popular sport utility vehicles (SUVs). The proposal, which would have required SUVs to increase their current fleet average of 20.5 miles per gallon (mpg) to 27.5 mpg by 2007, to equal the current passenger car fleet requirement, was shelved for a requirement to more modestly raise mpgs by cutting total SUV gasoline usage by 5 billion gallons over 6 years.

  12. Non-resonant energy harvester with elastic constraints for low rotating frequencies

    Science.gov (United States)

    Machado, Sebastián P.; Febbo, Mariano; Gatti, Claudio D.; Ramirez, José M.

    2017-11-01

    This paper presents a non-resonant piezoelectric energy harvester (PEH) which is designed to capture energy from low frequency rotational vibration. The proposed device works out of the plane of rotation where the motion of a mass-spring system is transferred to a piezoelectric layer with the intention to generate energy to power wireless structural monitoring systems or sensors. The mechanical structure is formed by two beams with rigid and elastic boundary conditions at the clamped end. On the free boundaries, heavy masses connected by a spring are placed in order to increase voltage generation and diminish the natural frequency. A mathematical framework and the equations governing the energy-harvesting system are presented. Numerical simulations and experimental verifications are performed for different rotation speeds ranging from 0.7 to 2.5 Hz. An output power of 125 μW is obtained for maximum rotating frequency demonstrating that the proposed design can collect enough energy for the suggested application.

  13. Finite Range Effects in Energies and Recombination Rates of Three Identical Bosons

    DEFF Research Database (Denmark)

    Sørensen, Peder Klokmose; V. Fedorov, D.; S. Jensen, A.

    2013-01-01

    at negative scattering length for creation of a bound trimer moves to higher or lower values depending on the sign of the effective range compared to the location of the threshold for the single-parameter zero-range model. Large effective ranges, corresponding to narrow resonances, are needed......We investigate finite-range effects in systems with three identical bosons. We calculate recombination rates and bound state spectra using two different finite-range models that have been used recently to describe the physics of cold atomic gases near Feshbach resonances where the scattering length...... is large. The models are built on contact potentials which take into account finite range effects; one is a two-channel model and the other is an effective range expansion model implemented through the boundary condition on the three-body wave function when two of the particles are at the same point...

  14. Detection of ochratoxin A (OTA) in coffee using chemiluminescence resonance energy transfer (CRET) aptasensor.

    Science.gov (United States)

    Jo, Eun-Jung; Mun, Hyoyoung; Kim, Su-Ji; Shim, Won-Bo; Kim, Min-Gon

    2016-03-01

    We report a chemiluminescence resonance energy transfer (CRET) aptasensor for the detection of ochratoxin A (OTA) in roasted coffee beans. The aptamer sequences used in this study are 5'-DNAzyme-Linker-OTA aptamer-3'-dabcyl. Dabcyl at the end of the OTA aptamer region plays as a quencher in CRET aptasensor. When hemin and OTA are added, the dabcyl-labeled OTA aptamer approaches to the G-quadruplex-hemin complex by formation of the G-quadruplex-OTA complex. The G-quadruplex-hemin complexes possess horseradish peroxidase (HRP)-like activity, and therefore, the HRP-mimicking DNAzyme (HRPzyme) catalyzes peroxidation in the presence of luminol and H2O2. Resonance energy transfer between luminol (donor) and dabcyl (acceptor) enables quenching of chemiluminescence signals. The signal decreases with increasing the concentration of OTA within the range of 0.1-100ngmL(-1) (limit of detection 0.22ngmL(-1)), and the level of recovery of the respective 1ngmL(-1) and 10ngmL(-1) spiked coffee samples was 71.5% and 93.3%. These results demonstrated the potential of the proposed method for OTA analysis in diverse foods. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Continuous Energy, Multi-Dimensional Transport Calculations for Problem Dependent Resonance Self-Shielding

    Energy Technology Data Exchange (ETDEWEB)

    T. Downar

    2009-03-31

    The overall objective of the work here has been to eliminate the approximations used in current resonance treatments by developing continuous energy multi-dimensional transport calculations for problem dependent self-shielding calculations. The work here builds on the existing resonance treatment capabilities in the ORNL SCALE code system.

  16. Biomolecular interactions probed by fluorescence resonance energy transfer

    Science.gov (United States)

    Lange, Daniela Charlotte

    2000-09-01

    This thesis describes how a physical phenomenon, Fluorescence Resonance Energy Transfer (FRET), can be exploited for the study of interactions between biomolecules. The physical basis of this phenomenon is discussed and it is described how some of its characteristics can be exploited in measurement. A recently introduced method, photobleaching FRET microscopy, was implemented and its image analysis refined to suit our biological context. Further, a new technique is proposed, which combines FRET with confocal laser scanning microscopy to optimize resolution and to allow for 3D-studies in living cells. The first part of this thesis presents the application of FRET to the study of oligomerization of G-protein coupled receptors (GPCRs), which was performed at the Fraser Laboratories at McGill University in Montreal. It is demonstrated how FRET microscopy allowed us to circumvent problems of traditional biochemical approaches and provided the first direct evidence for GPCR oligomerization in intact cells. We found that somatostatin receptors (SSTRs) functionally interact by forming oligomers with their own kind, with different SSTR isoforms, and even with distantly related GPCRs, such as dopamine receptors, the latter of which is breaking with the dogma that GPCRs would only pair up with their own kind. The high sensitivity of the FRET technique allowed us to characterize these interactions under more physiological conditions, which lead to the observation that oligomerization is induced by receptor agonist. We further studied the differential effects of agonists and antagonists on receptor oligomerization, leading to a model for the molecular mechanism underlying agonist/antagonist function and receptor activation. The second part was carried out at the Neurobiology Laboratory of the VA Medical Center in Newington, CT. The objective was to further our understanding of Niemann- Pick type C disease, which is characterized by a defect in intracellular cholesterol

  17. Interplay between relativistic energy corrections and resonant excitations in x-ray multiphoton ionization dynamics of Xe atoms

    Science.gov (United States)

    Toyota, Koudai; Son, Sang-Kil; Santra, Robin

    2017-04-01

    In this paper, we theoretically study x-ray multiphoton ionization dynamics of heavy atoms taking into account relativistic and resonance effects. When an atom is exposed to an intense x-ray pulse generated by an x-ray free-electron laser (XFEL), it is ionized to a highly charged ion via a sequence of single-photon ionization and accompanying relaxation processes, and its final charge state is limited by the last ionic state that can be ionized by a single-photon ionization. If x-ray multiphoton ionization involves deep inner-shell electrons in heavy atoms, energy shifts by relativistic effects play an important role in ionization dynamics, as pointed out in Phys. Rev. Lett. 110, 173005 (2013), 10.1103/PhysRevLett.110.173005. On the other hand, if the x-ray beam has a broad energy bandwidth, the high-intensity x-ray pulse can drive resonant photoexcitations for a broad range of ionic states and ionize even beyond the direct one-photon ionization limit, as first proposed in Nat. Photon. 6, 858 (2012), 10.1038/nphoton.2012.261. To investigate both relativistic and resonance effects, we extend the xatom toolkit to incorporate relativistic energy corrections and resonant excitations in x-ray multiphoton ionization dynamics calculations. Charge-state distributions are calculated for Xe atoms interacting with intense XFEL pulses at a photon energy of 1.5 keV and 5.5 keV, respectively. For both photon energies, we demonstrate that the role of resonant excitations in ionization dynamics is altered due to significant shifts of orbital energy levels by relativistic effects. Therefore, it is necessary to take into account both effects to accurately simulate multiphoton multiple ionization dynamics at high x-ray intensity.

  18. Measurement of the separation dependence of resonant energy transfer between cadmium selenide/zinc sulfide

    Science.gov (United States)

    Shafiei, Farbod

    An apparatus has been built to study the separation dependence of the interaction between small and large resonant groups of CdSe/ZnS nanocrystallite quantum dots (NQDs). A near-field scanning optical microscope (NSOM) is used to bring a group of mono-disperse 6 nm diameter dots close (near-field range) to a 8 nm diameter group of dots which are deposited on a solid immersion lens. 3rd excited excitonic energy level of large NQD does match the ground excitonic energy level of small NQDs. Combination of spectral and positional filtering allows us to measure the interaction between small numbers of NQDs, with the ultimate goal of identifying the interaction between individual dots. Quenching of the small NQDs photoluminescence signal has been observed as the small NQDs get to close proximity of large NQDs. Separation between two groups of the NQDs was changing in the range of 15-40nm during the experiment. The transition probability between these two groups of NQDs is theoretically obtained to be (2.72x10--47m 6)=R6. Forster radius, as a signature of energy transfer efficiency is extracted from experimental data to be 17 nm.

  19. Circularly polarized microwaves for magnetic resonance study in the GHz range: Application to nitrogen-vacancy in diamonds

    Energy Technology Data Exchange (ETDEWEB)

    Mrózek, M., E-mail: mariusz.mrozek@uj.edu.pl; Rudnicki, D. S.; Gawlik, W. [Institute of Physics, Jagiellonian University, Lojasiewicza 11, 30-348 Krakow (Poland); Mlynarczyk, J. [Department of Electronics, AGH University of Science and Technology, Mickiewicza 30, 30-059 Krakow (Poland)

    2015-07-06

    The ability to create time-dependent magnetic fields of controlled polarization is essential for many experiments with magnetic resonance. We describe a microstrip circuit that allows us to generate strong magnetic field at microwave frequencies with arbitrary adjusted polarization. The circuit performance is demonstrated by applying it to an optically detected magnetic resonance and Rabi nutation experiments in nitrogen-vacancy color centers in diamond. Thanks to high efficiency of the proposed microstrip circuit and degree of circular polarization of 85%; it is possible to address the specific spin states of a diamond sample using a low power microwave generator. The circuit may be applied to a wide range of magnetic resonance experiments with a well-controlled polarization of microwaves.

  20. Resonant electronic excitation energy transfer by exchange mechanism in the quantum dot system

    Science.gov (United States)

    Chikalova-Luzina, O. P.; Samosvat, D. M.; Vyatkin, V. M.; Zegrya, G. G.

    2017-11-01

    A microscopic theory of nonradiative resonance energy transfer between spherical A3B5 semiconductor quantum dots by the exchange mechanism is suggested. The interdot Coulomb interaction is taken into consideration. It is assumed that the quantum dot-donor and the quantum dot-acceptor are made from the same A3B5 compound and are embedded in the matrix of another material that produces potential barriers for electrons and holes. The dependences of the energy transfer rate on the quantum-dot system parameters are found in the frame of the Kane model that provides the most adequate description of the real spectra of A3B5 semiconductors. The analytical treatment is carried out with using the density matrix method, which enabled us to perform an energy transfer analysis both in the weak-interaction approximation and in the strong-interaction approximation. The numerical calculations showed the saturation of the energy transfer rate at the distances between the donor and the acceptor approaching the contact one. The contributions of the exchange and direct Coulomb intractions can be of the same order at the small distances and can have the same value in the saturation range.

  1. High Performing Ternary Solar Cells through Förster Resonance Energy Transfer between Nonfullerene Acceptors.

    Science.gov (United States)

    Yang, Lei; Gu, Wenxing; Hong, Ling; Mi, Yang; Liu, Feng; Liu, Ming; Yang, Yufei; Sharma, Bigyan; Liu, Xinfeng; Huang, Hui

    2017-08-16

    Nonradiative Förster resonance energy transfer (FRET) is an important mechanism of organic solar cells, which can improve the exciton migration over a long distance, resulting in improvement of efficiency of solar cells. However, the current observations of FRET are very limited, and the efficiencies are less than 9%. In this study, FRET effect was first observed between two nonfullerene acceptors in ternary solar cells, which improved both the absorption range and exciton harvesting, leading to the dramatic enhancement in the short circuit current and power conversion efficiency. Moreover, this strategy is proved to be a versatile platform for conjugated polymers with different bandgaps, resulting in a remarkable efficiency of 10.4%. These results demonstrated a novel method to enhance the efficiency of organic soar cells.

  2. A wide area Bipolar Cascade Resonant Cavity Light Emitting Diode for a Hybrid Range-Intensity Sensor

    Science.gov (United States)

    Turner, Reginald J.

    Autonomous Ground Vehicles (AGV) will require high-speed, real-time three dimensional (3-D) image processing to navigate treacherous terrain in order to complete their assigned mission without a human in the loop. LIDAR scanners of the 3-D variety, provide the necessary area coverage for 3-D image processing, but lack the speed to deliver the collected data for real-time processing. A novel Hybrid Range-Intensity System (HRIS) has been proposed for imaging large swaths of area very rapidly. This system is comprised of two infrared cameras, an illumination source, a control and coordination system to position the cameras, and signal processing algorithms to extract the contour image of the scene. This dissertation focused on the development of an illuminator for the HRIS. This illuminator enables faster image rendering and reduces the potential of errors in return signal data, that could be generated from extremely rough terrain. Four major achievements resulted from this work, which advance the field of 3-D image acquisition. The first is that the TJ is an effective current spreading layer for LEDs with mesa width up to 140 mum and current densities of ˜ 1 x 106A/cm2. The TJ allows fabrication of an efficient illuminator, with required geometry for the HRIS to operate as a real-time 3-D imaging system. Secondly, a design for a Bipolar Cascade-Resonant Cavity Light Emitting Diode (BC-RCLED) has been accomplished, that will illuminate the FOV of the hybrid-ranged intensity system with a single sweep of the beam. This device is capable of producing ˜ 330 mW of output power. Additionally, from this work, key parameters for HRIS design were identified. Using a collection optic with a 15 cm diameter, an HRIS mounting height of 1.5 m, and a detector integration time of 330 msec, a SNR of 20 dB was achieved. Lastly, we demonstrated that the BC-RCLED designed for the HRIS can deliver sufficient energy to produce the required SNR. Also, through parametric analysis, we

  3. Studies of Energy-Relevant Materials by Nuclear Magnetic Resonance

    Science.gov (United States)

    Cui, Jinfang

    In this thesis, we have used nuclear magnetic resonance (NMR) as a local probe to microscopically study three different families of energy-relevant complex materials, namely the 122 Fe-based superconductors Ca(Fe1-xCox)2As2, GeTe-based thermoelectric tellurides GeTe and detonation nanodiamond. In Chapter 3 and Chapter 4, we investigated the Co substitution effects on static and dynamic magnetic properties of the single-crystalline Ca(Fe 1-xCox)2As2 (x = 0, 0.023, 0.028, 0.033, 0.059) via 75As NMR and resistivity measurements. Robustness of the Fe magnetic moments was evidenced by only slight decreases of Hint, although T N is strongly suppressed with Co substitution in antiferromagnetic (AFM) state. In the paramagnetic (PM) state, the temperature dependence of Knight shift K for all crystals shows similar T-dependence of magnetic susceptibility chi. The spin fluctuations with the q = 0 components are suppressed with Delta/k B. On the other hand, the growth of the stripe-type AFM fluctuations with q = (pi, 0) or (0, pi) upon cooling in the PM state for all samples is evidenced by the T-dependence of (1/ T1Tchi). A pseudogap-like phenomenon, i.e., suppression of the AFM spin fluctuations, was discovered with decreasing temperature below a x-independent characteristic temperature T* ( 100 K) in samples with x ≥ 0.028. In addition, clear evidence for the coexistence and competition of the stripe-type antiferromagnetic and ferromagnetic (FM) spin correlations was given by modified Korringa ratio analysis in Chapter 4. In Chapter 5, we have carried out 125Te NMR measurements to study the electronic properties of Ge50Te50, Ag 2Ge48Te50 and Sb2Ge48Te 50. NMR shift K and 1/T1T of Ge50Te50 are nearly temperature independent at T electron correlations, while Korringa ratio increases slightly at high temperature, suggesting the slight enhancement of the electron correlation. In Chapter 6 and Chapter 7, we have used 13C NMR spectral editing technique to accurately analyze the

  4. Resonance energy transfer based electrochemiluminescence and fluorescence sensing of riboflavin using graphitic carbon nitride quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Huan [Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Chemistry & Chemical Engineering, Northwest Normal University, Lanzhou, Gansu 730070 (China); The Phytochemistry Key Laboratory of Tibetan Plateau of Qinghai Province, College of Pharmacy, Qinghai Nationalities University, Xining, Qinghai 810007 (China); Ma, Qin; Wang, Yanfeng; Wang, Caihe; Qin, Dongdong; Shan, Duoliang; Chen, Jing [Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Chemistry & Chemical Engineering, Northwest Normal University, Lanzhou, Gansu 730070 (China); Lu, Xiaoquan, E-mail: luxq@nwnu.edu.cn [Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Chemistry & Chemical Engineering, Northwest Normal University, Lanzhou, Gansu 730070 (China)

    2017-06-22

    Graphitic carbon nitride quantum dots (g-CNQDs) are rarely used in the field of electrochemiluminescence. In this paper, g-CNQDs have a strong and stable electrochemiluminescence (ECL) signal generated in the presence of co-reactant K{sub 2}S{sub 2}O{sub 8}. The ECL signal of g-CNQDs was quenched by the mechanism of resonance energy transfer (RET) between donor g-CNQDs and receptor riboflavin (RF) that is proved by UV-vis absorption spectroscopy, electrochemiluminescence and fluorescence emission spectroscopy analysis technology. Therefore, we achieved detection of the riboflavin content in the drug tablets of vitamin B{sub 2} using ECL and FL. The determination results of ECL showed that the riboflavin content of the drug vitamin B{sub 2} (VB{sub 2}) tablets was consistent with the fluorescence (FL) analysis, with wider linear range of 0.02–11 μM and lower minimum detection limit of 0.63 nM (S/N = 3) than FL. Hence, the riboflavin content in human serum was further detected using ECL. The relative standard deviation is less than 6.5%, with an acceptable recovery of 95.33%–104.22%, which means that this sensor has potential applications in the actual sample analysis. As a new ECL luminary, g-CNQDs have opened a new field for the development and application of ECL sensor. - Highlights: • G-CNQDs proposed as a new luminophore for ECL. • ECL signal was strong and stable in the presence of co-reactant K{sub 2}S{sub 2}O{sub 8}. • Based on the resonance energy transfer between g-CNQDs and riboflavin. • ECL has wider linear range and lower detection limit than FL.

  5. Improving energy harvesting by stochastic resonance in a laminated bistable beam

    Science.gov (United States)

    Li, HaiTao; Qin, WeiYang; Deng, Wangzheng; Tian, Ruilan

    2016-03-01

    This paper presents a bistable energy harvesting device as piezoelectric beam acted upon by a harmonic axial load and a transverse random excitation. A comprehensive analytical study for stochastic resonance in the bistable mechanical system is carried out, from which the system can harvest energy at a high efficiency. The bistable electromechanical model is set up and the corresponding equations are derived by extended Hamilton principle. The condition for occurrence of stochastic resonance is derived by Kramers rate. Numerical simulation is carried out and results are obtained. Stochastic resonance is proved and observed when the system is excited by a Gaussian white noise. The output voltage and power conversion in the condition of stochastic resonance is noticeably higher than those in other conditions. These results can provide a theoretical method for preliminary design and optimization of parameters, which can improve the efficiency of energy harvester.

  6. Remote double resonance coupling of radar energy to ionospheric irregularities

    Science.gov (United States)

    Kennel, C. F.

    1971-01-01

    Experimental results indicate that low frequency modulation of a high power radar beam, tuned to one of the critical frequencies of the ionosphere, may produce field-aligned density irregularities when the modulation frequency matches an ionospheric eigenfrequency. By choosing the radar carrier frequency and polarization, a number of interaction layers were selected. The variety of possible excitations shows that the double resonance technique may be adaptable to a number of different objectives.

  7. Investigations and system design for simultaneous energy and data transmission through inductively coupled resonances

    Science.gov (United States)

    Schmidt, C.; Lloret Fuentes, E.; Buchholz, M.

    2015-11-01

    Wireless Power Transfer (WPT) with simultaneous data transmission through coupled magnetic resonators is investigated in this paper. The development of this system is dedicated to serve as a basis for applications in the field of Ambient Assisted Living (AAL), for example tracking vital parameters remotely, charge and control sensors and so on. Due to these different scenarios we consider, it is important to have a system which is reliable under the circumstance of changing positioning of the receiving device. State of the art radio systems would be able to handle this. Nevertheless, energy harvesting from far field sources is not sufficient to power the devices additionally on mid-range distances. For this reason, coupled magnetic resonant circuits are proposed as a promising alternative, although suffering from more complex positioning dependency. Based on measurements on a simple prototype system, an equivalent circuit description is used to model the transmission system dependent on different transmission distances and impedance matching conditions. Additionally, the simulation model is used to extract system parameters such as coupling coefficients, coil resistance and self-capacitance, which cannot be calculated in a simple and reliable way. Furthermore, a mathematical channel model based on the schematic model has been built in MATLAB©. It is used to point out the problems occurring in a transmission system with variable transmission distance, especially the change of the passband's centre frequency and its bandwidth. Existing solutions dealing with this distance dependent behaviour, namely the change of the transmission frequency dependent on distance and the addition of losses to the resonators to increase the bandwidth, are considered as not inventive. First, changing the transmission frequency increases the complexity in the data transmission system and would use a disproportional total bandwidth compared to the actually available bandwidth

  8. Resonance

    DEFF Research Database (Denmark)

    Petersen, Nils Holger

    2014-01-01

    A chapter in a book about terminology within the field of medievalism: the chapter discusses the resonance of medieval music and ritual in modern (classical) music culture and liturgical practice.......A chapter in a book about terminology within the field of medievalism: the chapter discusses the resonance of medieval music and ritual in modern (classical) music culture and liturgical practice....

  9. Alternative separation of exchange and correlation energies in range-separated density-functional perturbation theory

    DEFF Research Database (Denmark)

    Cornaton, Y.; Stoyanova, A.; Jensen, Hans Jørgen Aagaard

    2013-01-01

    An alternative separation of short-range exchange and correlation energies is used in the framework of second-order range-separated density-functional perturbation theory. This alternative separation was initially proposed by Toulouse and relies on a long-range-interacting wave function instead...... of the noninteracting Kohn-Sham one. When second-order corrections to the density are neglected, the energy expression reduces to a range-separated double-hybrid (RSDH) type of functional, RSDHf, where "f" stands for "full-range integrals" as the regular full-range interaction appears explicitly in the energy...... on the potential energy curves in the equilibrium region, improving the accuracy of binding energies and equilibrium bond distances when second-order perturbation theory is appropriate....

  10. A dual resonant rectilinear-to-rotary oscillation converter for low frequency broadband electromagnetic energy harvesting

    Science.gov (United States)

    Deng, Wei; Wang, Ya

    2017-09-01

    This paper reports a dual resonant rectilinear-to-rotary oscillation converter (RROC) for low frequency broadband electromagnetic energy harvesting from ambient vibrations. An approximate theoretical model has been established to integrate the electromechanical coupling into a comprehensive electromagnetic-dynamic model of the dual resonant RROC. Numerical simulation has proved the nature of dual resonances by revealing that both the rectilinear resonance and the rotary resonance could be achieved when the stand-alone rectilinear oscillator (RLO) and the stand-alone rotary oscillator (RTO) were excited independently. Simulation on the magnetically coupled RROC has also shown that the rectilinear resonance and the rotary resonance could be obtained simultaneously in the low-frequency region (2-14 Hz) with well-defined restoring torque (M r ) and the initial rotation angle of the RLO (ψ). The magnetic interaction patterns between the rectilinear and the RTOs have been categorized based on aforementioned simulation results. Both simulation and experimental results have demonstrated broadband output attributing from the dual resonances. Experimental results have also indicated that the RROC could have wide bandwidth in a much lower frequency region (2-8 Hz) even without the rotary resonance as long as the system parameters are carefully tuned. Parameter analysis on different values of M r and ψ are experimentally carried out to provide a quantitative guidance of designing the RROC to achieve an optimal power density.

  11. Design analysis of doped-silicon surface plasmon resonance immunosensors in mid-infrared range.

    Science.gov (United States)

    DiPippo, William; Lee, Bong Jae; Park, Keunhan

    2010-08-30

    This paper reports the design analysis of a microfabricatable mid-infrared (mid-IR) surface plasmon resonance (SPR) sensor platform. The proposed platform has periodic heavily doped profiles implanted into intrinsic silicon and a thin gold layer deposited on top, making a physically flat grating SPR coupler. A rigorous coupled-wave analysis was conducted to prove the design feasibility, characterize the sensor's performance, and determine geometric parameters of the heavily doped profiles. Finite element analysis (FEA) was also employed to compute the electromagnetic field distributions at the plasmon resonance. Obtained results reveal that the proposed structure can excite the SPR on the normal incidence of mid-IR light, resulting in a large probing depth that will facilitate the study of larger analytes. Furthermore, the whole structure can be microfabricated with well-established batch protocols, providing tunability in the SPR excitation wavelength for specific biosensing needs with a low manufacturing cost. When the SPR sensor is to be used in a Fourier-transform infrared (FTIR) spectroscopy platform, its detection sensitivity and limit of detection are estimated to be 3022 nm/RIU and ~70 pg/mm(2), respectively, at a sample layer thickness of 100 nm. The design analysis performed in the present study will allow the fabrication of a tunable, disposable mid-IR SPR sensor that combines advantages of conventional prism and metallic grating SPR sensors.

  12. Resonance Energy of an Arene Hydrocarbon from Heat of Combustion Measurements.

    Science.gov (United States)

    Kolesnichenko, Vladimir L

    2015-12-08

    A simple experimental method for determination of the resonance energy by measuring the energies of combustion for two isomeric compounds, aromatic 1-tert-butyl-3,5-dimethylbenzene and nonaromatic trans,trans,cis-1,5,9-cyclododecatriene is proposed. Both compounds not only have the same molecular formula, but also contain the same number of sp2 and sp3 carbon atoms. After converting the obtained values into the gas phase heats of combustion and subtracting one value from another, the resulting mean resonance energy of 184 kJ/mol was obtained. The proposed method can be offered as an experiment for an undergraduate physical chemistry lab curriculum.

  13. Multi-directional energy harvesting by piezoelectric cantilever-pendulum with internal resonance

    Energy Technology Data Exchange (ETDEWEB)

    Xu, J.; Tang, J., E-mail: jtang@engr.uconn.edu [Department of Mechanical Engineering, The University of Connecticut, Storrs, Connecticut 06269 (United States)

    2015-11-23

    This letter reports a piezoelectric cantilever-pendulum design for multi-directional energy harvesting. A pendulum is attached to the tip of a piezoelectric cantilever-type energy harvester. This design aims at taking advantage of the nonlinear coupling between the pendulum motion in 3-dimensional space and the beam bending vibration at resonances. Experimental studies indicate that, under properly chosen parameters, 1:2 internal resonance can be induced, which enables the multi-directional energy harvesting with a single cantilever. The advantages of the design with respect to traditional piezoelectric cantilever are examined.

  14. Efficiency of targeted energy transfers in coupled nonlinear oscillators associated with 1:1 resonance captures: Part II, analytical study

    Science.gov (United States)

    Sapsis, T. P.; Vakakis, A. F.; Gendelman, O. V.; Bergman, L. A.; Kerschen, G.; Quinn, D. D.

    2009-08-01

    We study targeted energy transfer in a two degree-of-freedom damped system under the condition of 1:1 transient resonance capture. The system consists of a linear oscillator strongly coupled to an essentially nonlinear attachment or nonlinear energy sink. In a companion paper [Quinn et al., Efficiency of targeted energy transfers in coupled nonlinear oscillators associated with 1:1 resonance captures: part I, Journal of Sound and Vibration 311 (2008) 1228-1248] we studied the underlying structure of the Hamiltonian dynamics of this system, and showed that for sufficiently small values of viscous damping, nonlinear damped transitions are strongly influenced by the underlying topological structure of periodic and quasiperiodic orbits of the Hamiltonian system. In this work direct analytical treatment of the governing strongly nonlinear damped equations of motion is performed through slow/fast partitions of the transient responses, in order to investigate analytically the parameter region of optimal targeted energy transfer. To this end, we determine the characteristic time scales of the dynamics that influence the capacity of the nonlinear attachment to passively absorb and locally dissipate broadband energy from the linear oscillator. Then, we prove that optimal targeted energy transfer is realized for initial energies close to the neighborhood of a homoclinic orbit of the underlying Hamiltonian system. We study analytically transient orbits resulting as perturbations of the homoclinic orbit in the weakly damped system, and show that this yields an additional slow-time scale in the averaged dynamics, and leads to optimal targeted energy transfer from the linear oscillator to the nonlinear energy sink in a single "super-slow" half-cycle. We show that at higher energies, this "super-slow" half-cycle is replaced by strong nonlinear beats, which lead to significant but suboptimal targeted energy transfer efficiency. Finally, we investigate numerically targeted energy

  15. Resonances

    DEFF Research Database (Denmark)

    an impetus or drive to that account: change, innovation, rupture, or discontinuity. Resonances: Historical Essays on Continuity and Change explores the historiographical question of the modes of interrelation between these motifs in historical narratives. The essays in the collection attempt to realize...... theoretical consciousness through historical narrative ‘in practice’, by discussing selected historical topics from Western cultural history, within the disciplines of history, literature, visual arts, musicology, archaeology, philosophy, and theology. The title Resonances indicates the overall perspective...... of the book: how connotations of past meanings may resonate through time, in new contexts, assuming new meanings without surrendering the old....

  16. Comparison of static and microfluidic protease assays using modified bioluminescence resonance energy transfer chemistry.

    Directory of Open Access Journals (Sweden)

    Nan Wu

    Full Text Available BACKGROUND: Fluorescence and bioluminescence resonance energy transfer (F/BRET are two forms of Förster resonance energy transfer, which can be used for optical transduction of biosensors. BRET has several advantages over fluorescence-based technologies because it does not require an external light source. There would be benefits in combining BRET transduction with microfluidics but the low luminance of BRET has made this challenging until now. METHODOLOGY: We used a thrombin bioprobe based on a form of BRET (BRET(H, which uses the BRET(1 substrate, native coelenterazine, with the typical BRET(2 donor and acceptor proteins linked by a thrombin target peptide. The microfluidic assay was carried out in a Y-shaped microfluidic network. The dependence of the BRET(H ratio on the measurement location, flow rate and bioprobe concentration was quantified. Results were compared with the same bioprobe in a static microwell plate assay. PRINCIPAL FINDINGS: The BRET(H thrombin bioprobe has a lower limit of detection (LOD than previously reported for the equivalent BRET(1-based version but it is substantially brighter than the BRET(2 version. The normalised BRET(H ratio of the bioprobe changed 32% following complete cleavage by thrombin and 31% in the microfluidic format. The LOD for thrombin in the microfluidic format was 27 pM, compared with an LOD of 310 pM, using the same bioprobe in a static microwell assay, and two orders of magnitude lower than reported for other microfluidic chip-based protease assays. CONCLUSIONS: These data demonstrate that BRET based microfluidic assays are feasible and that BRET(H provides a useful test bed for optimising BRET-based microfluidics. This approach may be convenient for a wide range of applications requiring sensitive detection and/or quantification of chemical or biological analytes.

  17. Long-Range Plasmon Assisted Energy Transfer Between Two Fluorescent Emitters

    CERN Document Server

    Bouchet, D; Carminati, R; De Wilde, Y; Krachmalnicoff, V

    2016-01-01

    We demonstrate plasmon assisted energy transfer between two fluorophores located at distances up to $7\\; \\mu$m on the top of a thin silver film. Thanks to the strong confinement and large propagation length of surface plasmon polaritons, the range of the energy transfer is almost two orders of magnitude larger than the values reported in the literature so far. The parameters driving the energy transfer range are thoroughly characterized and are in very good agreement with theoretically expected values. This work shows the potential of plasmonic structures for efficient long-range energy transfer and opens rich perspectives for the study of collective emission phenomena.

  18. Calculation of the quasi-energies and resonances behavior of the hydrogen Lyman-alpha problem

    Science.gov (United States)

    Ruyten, Wilhelmus M.

    1992-01-01

    Recently, Bakshi and Kalman presented numerical results for the quasi-energies of the n = 2 multiplet in the hydrogen Lyman-alpha transition for a plasma in which both strong static and oscillating electric fields are present. Recent work on related magnetic and optical resonance problems provides a simplified mathematical treatment, as well as greater insight into the complex resonance behavior of this interaction.

  19. Design of serial linkage-type vibration energy harvester with three resonant frequencies

    Science.gov (United States)

    Kim, Hyun Soo; Kim, Jun Woo; Park, Shi-Baek; Choi, Yong Je

    2017-11-01

    This paper presents a new design method of a planar 3 degrees-of-freedom(DOF) serial linkage-type vibration energy harvester with a single proof mass. The harvester is designed to generate electrical power at equally spaced three target resonant frequencies which can be chosen arbitrarily. For given target frequencies and a proof mass, the design method involves (1) the determination of the stiffness matrix, (2) the synthesis of the stiffness by means of a parallel connection of three line springs and (3) its conversion into a 3DOF device connected serially by torsional springs. The torsional springs are realized by the flexible hinge joints and the polyvinylidene fluoride(PVDF) films are attached on the joints. Upon determination of the desired stiffness matrix, the SQP algorithm is utilized to find the optimum locations and spring constants of the serial hinge joints for the minimum difference among three electrical power peaks. The FEM analysis and experiments are conducted to verify the proposed design method. Three measured resonant power peaks occur at 24.7, 30.4 and 33.6 Hz comparing to the target frequencies of 25, 30 and 35 Hz. The normalized maximum power of 14.5 {{uW}}/{({{{ms}}}-2)}2 is generated at 24.7 Hz. The experimental results also demonstrate that the harvester can generate at least 18.6% of the peak power throughout the frequency range from 23.1 to 36.5 Hz, which ensures consistently acquirable power within the operating frequency range by virtue of the coupled effect of a serial linkage-type structure.

  20. Metastable states and energy flow pathway in square graphene resonators

    Science.gov (United States)

    Wang, Yisen; Zhu, Zhigang; Zhang, Yong; Huang, Liang

    2018-01-01

    Nonlinear interaction between flexural modes is critical to heat conductivity and mechanical vibration of two-dimensional materials such as graphene. Much effort has been devoted to understand the underlying mechanism. In this paper, we examine solely the out-of-plane flexural modes and identify their energy flow pathway during thermalization process. The key is the development of a universal scheme that numerically characterizes the strength of nonlinear interactions between normal modes. In particular, for our square graphene system, the modes are grouped into four classes by their distinct symmetries. The couplings are significantly larger within a class than between classes. As a result, the equations for the normal modes in the same class as the initially excited one can be approximated by driven harmonic oscillators, therefore, they get energy almost instantaneously. Because of the hierarchical organization of the mode coupling, the energy distribution among the modes will arrive at a stable profile, where most of the energy is localized on a few modes, leading to the formation of "natural package" and metastable states. The dynamics for modes in other symmetry classes follows a Mathieu type of equation, thus, interclass energy flow, when the initial excitation energy is small, starts typically when there is a mode that lies in the unstable region in the parameter space of Mathieu equation. Due to strong coupling of the modes inside the class, the whole class will get energy and be lifted up by the unstable mode. This characterizes the energy flow pathway of the system. These results bring fundamental understandings to the Fermi-Pasta-Ulam problem in two-dimensional systems with complex potentials, and reveal clearly the physical picture of dynamical interactions between the flexural modes, which will be crucial to the understanding of their abnormal contribution to heat conduction and nonlinear mechanical vibrations.

  1. Measurements of the capture cross sections of natural silver in the resonance range with the time of flight technique

    Directory of Open Access Journals (Sweden)

    Šalamon L.

    2017-01-01

    Full Text Available Neutron capture cross section measurements have been performed at the time-of-flight facility GELINA of the EC-JRC-Geel. Prompt gamma rays, originating from a natural silver sample, were detected by a pair of C6D6 liquid scintillation detectors. The total energy detection principle in combination with the pulse height weighting technique has been used. In this contribution the experimental details together with the data reduction process are described. In addition, first results of calculations with REFIT are presented to verify the quality of recommended cross section data in the resolved resonance region.

  2. On square-wave-driven stochastic resonance for energy harvesting in a bistable system

    Directory of Open Access Journals (Sweden)

    Dongxu Su

    2014-11-01

    Full Text Available Stochastic resonance is a physical phenomenon through which the throughput of energy within an oscillator excited by a stochastic source can be boosted by adding a small modulating excitation. This study investigates the feasibility of implementing square-wave-driven stochastic resonance to enhance energy harvesting. The motivating hypothesis was that such stochastic resonance can be efficiently realized in a bistable mechanism. However, the condition for the occurrence of stochastic resonance is conventionally defined by the Kramers rate. This definition is inadequate because of the necessity and difficulty in estimating white noise density. A bistable mechanism has been designed using an explicit analytical model which implies a new approach for achieving stochastic resonance in the paper. Experimental tests confirm that the addition of a small-scale force to the bistable system excited by a random signal apparently leads to a corresponding amplification of the response that we now term square-wave-driven stochastic resonance. The study therefore indicates that this approach may be a promising way to improve the performance of an energy harvester under certain forms of random excitation.

  3. On square-wave-driven stochastic resonance for energy harvesting in a bistable system

    Energy Technology Data Exchange (ETDEWEB)

    Su, Dongxu, E-mail: sudx@iis.u-tokyo.ac.jp [Graduate School of Engineering, The University of Tokyo, Tokyo 1538505 (Japan); Zheng, Rencheng; Nakano, Kimihiko [Institute of Industrial Science, The University of Tokyo, Tokyo 1538505 (Japan); Cartmell, Matthew P [Department of Mechanical Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom)

    2014-11-15

    Stochastic resonance is a physical phenomenon through which the throughput of energy within an oscillator excited by a stochastic source can be boosted by adding a small modulating excitation. This study investigates the feasibility of implementing square-wave-driven stochastic resonance to enhance energy harvesting. The motivating hypothesis was that such stochastic resonance can be efficiently realized in a bistable mechanism. However, the condition for the occurrence of stochastic resonance is conventionally defined by the Kramers rate. This definition is inadequate because of the necessity and difficulty in estimating white noise density. A bistable mechanism has been designed using an explicit analytical model which implies a new approach for achieving stochastic resonance in the paper. Experimental tests confirm that the addition of a small-scale force to the bistable system excited by a random signal apparently leads to a corresponding amplification of the response that we now term square-wave-driven stochastic resonance. The study therefore indicates that this approach may be a promising way to improve the performance of an energy harvester under certain forms of random excitation.

  4. Condensation versus long-range interaction: Competing quantum phases in bosonic optical lattice systems at near-resonant Rydberg dressing

    Science.gov (United States)

    Geißler, Andreas; Vasić, Ivana; Hofstetter, Walter

    2017-06-01

    Recent experiments have shown that (quasi)crystalline phases of Rydberg-dressed quantum many-body systems in optical lattices (OL) are within reach. Rydberg systems naturally possess strong long-range interactions due to the large polarizability of Rydberg atoms. Thus a wide range of quantum phases has been predicted, such as a devil's staircase of lattice-incommensurate density wave phases as well as the more exotic lattice supersolid order for bosonic systems, as considered in our work. Guided by results in the "frozen"-gas limit, we study the ground-state phase diagram at finite hopping amplitudes and in the vicinity of resonant Rydberg driving while fully including the long-range tail of the van der Waals interaction. Simulations within real-space bosonic dynamical mean-field theory yield an extension of the devil's staircase into the supersolid regime where the competition of condensation and interaction leads to a sequence of crystalline phases.

  5. Modeling the efficiency of Förster resonant energy transfer from energy relay dyes in dye-sensitized solar cells

    KAUST Repository

    Hoke, Eric T.

    2010-02-11

    Förster resonant energy transfer can improve the spectral breadth, absorption and energy conversion efficiency of dye sensitized solar cells. In this design, unattached relay dyes absorb the high energy photons and transfer the excitation to sensitizing dye molecules by Förster resonant energy transfer. We use an analytic theory to calculate the excitation transfer efficiency from the relay dye to the sensitizing dye accounting for dynamic quenching and relay dye diffusion. We present calculations for pores of cylindrical and spherical geometry and examine the effects of the Förster radius, the pore size, sensitizing dye surface concentration, collisional quenching rate, and relay dye lifetime. We find that the excitation transfer efficiency can easily exceed 90% for appropriately chosen dyes and propose two different strategies for selecting dyes to achieve record power conversion efficiencies. © 2010 Optical Society of America.

  6. Effectiveness Testing of a Piezoelectric Energy Harvester for an Automobile Wheel Using Stochastic Resonance

    Directory of Open Access Journals (Sweden)

    Yunshun Zhang

    2016-10-01

    Full Text Available The collection of clean power from ambient vibrations is considered a promising method for energy harvesting. For the case of wheel rotation, the present study investigates the effectiveness of a piezoelectric energy harvester, with the application of stochastic resonance to optimize the efficiency of energy harvesting. It is hypothesized that when the wheel rotates at variable speeds, the energy harvester is subjected to on-road noise as ambient excitations and a tangentially acting gravity force as a periodic modulation force, which can stimulate stochastic resonance. The energy harvester was miniaturized with a bistable cantilever structure, and the on-road noise was measured for the implementation of a vibrator in an experimental setting. A validation experiment revealed that the harvesting system was optimized to capture power that was approximately 12 times that captured under only on-road noise excitation and 50 times that captured under only the periodic gravity force. Moreover, the investigation of up-sweep excitations with increasing rotational frequency confirmed that stochastic resonance is effective in optimizing the performance of the energy harvester, with a certain bandwidth of vehicle speeds. An actual-vehicle experiment validates that the prototype harvester using stochastic resonance is capable of improving power generation performance for practical tire application.

  7. Measuring distances within unfolded biopolymers using fluorescence resonance energy transfer: The effect of polymer chain dynamics on the observed fluorescence resonance energy transfer efficiency

    Science.gov (United States)

    Makarov, Dmitrii E.; Plaxco, Kevin W.

    2009-01-01

    Recent years have seen a number of investigations in which distances within unfolded proteins, polypeptides, and other biopolymers are probed via fluorescence resonance energy transfer, a method that relies on the strong distance dependence of energy transfer between a pair of dyes attached to the molecule of interest. In order to interpret the results of such experiments it is commonly assumed that intramolecular diffusion is negligible during the excited state lifetime. Here we explore the conditions under which this “frozen chain” approximation fails, leading to significantly underestimated donor-acceptor distances, and describe a means of correcting for polymer dynamics in order to estimate these distances more accurately. PMID:19725638

  8. Electrical and thermal tuning of quality factor and free spectral range of optical resonance of nematic liquid crystal microdroplets

    Science.gov (United States)

    Sofi, Junaid Ahmad; Mohiddon, M. A.; Dutta, N.; Dhara, Surajit

    2017-08-01

    We experimentally study the effect of temperature and electric field on the quality (Q ) factor and free spectral range (FSR) of whispering-gallery-mode optical resonance of dye-doped nematic liquid crystal microdroplets. Both the Q factor and the FSR are highly sensitive to the temperature and electric field and are tunable. The Q factor decreases, whereas the FSR increases substantially, with increasing temperature and electric field. The variation of the Q factor and FSR is understood based on the change in the effective refractive index and the dynamic size of the microdroplets.

  9. Fluorescence resonance energy transfer from tryptophan in human ...

    Indian Academy of Sciences (India)

    TECS

    After excitation, competition prevails between the various decay processes, namely, fluorescence and non-radiative deactivations, inclu- ding energy transfer to the surrounding molecules. Efficiency of FRET is known to depend on the in- verse sixth power of the intermolecular distance bet- ween the donor and the acceptor ...

  10. Distance dependence of fluorescence resonance energy transfer ∑

    Indian Academy of Sciences (India)

    Administrator

    excitations namely, graphene, a two-dimensional semiconducting sheet and the case of such a ..... graphene. We now consider the process of energy transfer from a fluorescent dye to graphene (see figure 1). 6,7. We use the tight-binding model for graphene. 8. The ...... to a monolayer of semiconductor nanocrystals.

  11. Fluorescence resonance energy transfer between conjugated molecules infiltrated in three-dimensional opal photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Lu; Sui, Ning; Wang, Ying-Hui, E-mail: yinghui_wang@jlu.edu.cn; Qian, Cheng; Ma, Yu-Guang; Zhang, Han-Zhuang, E-mail: zhanghz@jlu.edu.cn

    2015-02-15

    Fluorescence resonance energy transfer (FRET) from Coumarin 6 (C-6) to Sulforhodamine B (S-B) infiltrated into opal PMMA (poly-methyl-methacrylate) photonic crystals (PCs) has been studied in detail. The intrinsic mesh micro-porous structure of opal PCs could increase the luminescent efficiency through inhibiting the intermolecular interaction. Meanwhile, its structure of periodically varying refractive indices could also modify the FRET through affecting the luminescence characteristics of energy donor or energy acceptor. The results demonstrate that the FRET efficiency between conjugated dyes was easily modified by opal PCs. - Highlights: • We investigate the fluorescence resonance energy transfer between two kinds of dyes. • These two kinds of dyes are infiltrated in PMMA opal photonic crystals. • The structure of opal PCs could improve the luminescent characteristics. • The structure of opal PCs could improve the energy transfer characteristics.

  12. Energy storage and dispersion of surface acoustic waves trapped in a periodic array of mechanical resonators

    DEFF Research Database (Denmark)

    Dühring, Maria Bayard; Laude, Vincent; Khelif, Abdelkrim

    2009-01-01

    confined to the electrode as compared to the total mechanical energy is calculated and is found to be increasing for increasing aspect ratio and to tend to a definite limit for the two families of surface waves. This observation is in support of the interpretation that high aspect ratio electrodes act...... as resonators storing mechanical energy. These resonators are evanescently coupled by the surface. The dispersion diagram is presented and shows very low group velocities as the wave vector approaches the limit of the first Brillouin zone. ©2009 American Institute of Physics...

  13. New experimental study of low-energy (p,gamma) resonances in magnesium isotopes

    CERN Document Server

    Limata, B; Formicola, A; Imbriani, G; Junker, M; Becker, H W; Bemmerer, D; Best, A; Bonetti, R; Broggini, C; Caciolli, A; Corvisiero, P; Costantini, H; DiLeva, A; Elekes, Z; Fülöp, Zs; Gervino, G; Guglielmetti, A; Gustavino, C; Gyürky, Gy; Lemut, A; Marta, M; Mazzocchi, C; Menegazzo, R; Prati, P; Roca, V; Rolfs, C; Alvarez, C Rossi; Salvo, C; Somorjai, E; Straniero, O; Terrasi, F; Trautvetter, H -P

    2010-01-01

    Proton captures on Mg isotopes play an important role in the Mg-Al cycle active in stellar H shell burning. In particular, the strengths of low-energy resonances with E < 200 keV in 25Mg(p,gamma)26Al determine the production of 26Al and a precise knowledge of these nuclear data is highly desirable. Absolute measurements at such low-energies are often very difficult and hampered by gamma-ray background as well as changing target stoichiometry during the measurements. The latter problem can be partly avoided using higher energy resonances of the same reaction as a normalization reference. Hence the parameters of suitable resonances have to be studied with adequate precision. In the present work we report on new measurements of the resonance strengths omega_gamma of the E = 214, 304, and 326 keV resonances in the reactions 24Mg(p,gamma)25Al, 25Mg(p,gamma)26Al, and 26Mg(p,gamma)27Al, respectively. These studies were performed at the LUNA facility in the Gran Sasso underground laboratory using multiple experime...

  14. RESONANCE

    Indian Academy of Sciences (India)

    Nuclear magnetic resonance (NMR) is a mani- festation of an intrinsic property of the nucleus, i.e. nuclear spin angular momen- tum. Spin angular momentum gives rise to magnetic moments. Thus, nuclei that pos- sess net magnetic moments behave like very small bar magnets. NMR spectroscopy in- volves the study of the ...

  15. A Fixed-Frequency Bidirectional Resonant DC-DC Converter Suitable for Wide Voltage Gain Range

    DEFF Research Database (Denmark)

    Shen, Yanfeng; Wang, Huai; Blaabjerg, Frede

    2017-01-01

    . It is realized by configuring a full-bridge mode and a half-bridge mode operation during each switching cycle. The fixed-frequency phase-shift control schemes are applied and the normalized voltage gain can be always from 0.5 to 1, regardless of the load. The transformer root-mean-square (RMS) currents in both...... the forward and the reverse modes have a negligible variation with respect to the voltage gain, which is beneficial to low conduction losses throughout a wide voltage range. Moreover, the applied MOSFETs are soft-switched, allowing for minimum switching losses. Both the operation principles...

  16. Surface Plasmon Resonance sensor showing enhanced sensitivity for CO2 detection in the mid-infrared range.

    Science.gov (United States)

    Herminjard, Sylvain; Sirigu, Lorenzo; Herzig, Hans Peter; Studemann, Eric; Crottini, Andrea; Pellaux, Jean-Paul; Gresch, Tobias; Fischer, Milan; Faist, Jérôme

    2009-01-05

    We present the first optical sensor based on Surface Plasmon Resonance (SPR) operating in the mid-infrared range. The experimental setup is based on a Kretschmann geometry with Ti/Au layers deposited on a CaF(2) prism where light excitation is provided by a Quantum Cascade Laser (QCL) source. Evidence of SPR is presented and the sensing capability of the system is demonstrated by using CO(2) and N(2) mixtures as test samples. Due to the absorption of CO(2) at this wavelength, it is shown that the sensitivity of this configuration is five times higher than a similar SPR sensor operating in the visible range of the spectrum.

  17. Group velocity effect on resonant, long-range wake-fields in slow wave structures

    CERN Document Server

    Smirnov, A V

    2002-01-01

    Synchronous wake-fields in a dispersive waveguide are derived in a general explicit form on the basis of a rigorous electro-dynamical approach using Fourier transformations. The fundamental role of group velocity in wake-field propagation, calculation of attenuation, amplitudes, form-factors and loss-factors is analyzed for single bunch radiation. Adiabatic tapering of the waveguide and bunch density variation is taken into account analytically for the time-domain fields. Effects of field 'compression/expansion' and group delays are demonstrated. The role of these effects is discussed for single bunch wake-fields, transient beam loading, BBU and HOMs. A novel waveguide structure with central rf coupling and both positive and negative velocities is proposed. It can be used effectively in both high-energy accelerators and single-section linacs.

  18. MEMS fabricated energy harvesting device with 2D resonant structure

    DEFF Research Database (Denmark)

    Crovetto, Andrea; Wang, Fei; Triches, Marco

    This paper reports on a MEMS energy harvester able to generate power from two perpendicular ambient vibration directions. CYTOP polymer is used both as the electret material for electrostatic transduction and as a bonding interface for low-temperature wafer bonding. With final chip size of ~1 cm2......, an output power of 32.5 nW is reached with an external load of 17 MΩ, under a harmonic source motion with acceleration RMS amplitude 0.03 g (0.3 m/s2) and frequency 179 Hz....

  19. Nonlinear resonances and energy transfer in finite granular chains.

    Science.gov (United States)

    Lydon, Joseph; Theocharis, Georgios; Daraio, Chiara

    2015-02-01

    In the present work we test experimentally and compute numerically the stability and dynamics of harmonically driven monoatomic granular chains composed of an increasing number of particles N(N=1-50). In particular, we investigate the inherent effects of dissipation and finite size on the evolution of bifurcation instabilities in the statically compressed case. The findings of the study suggest that the nonlinear bifurcation phenomena, which arise due to finite size, can be useful for efficient energy transfer away from the drive frequency in transmitted waves.

  20. FAST TRACK COMMUNICATION: Study of low-energy resonant metastability exchange in argon by a pulsed merging beam technique

    Science.gov (United States)

    Grucker, J.; Baudon, J.; Perales, F.; Dutier, G.; Vassilev, G.; Bocvarski, V.; Ducloy, M.

    2008-01-01

    The resonant metastability exchange process in low-energy collinear collisions between metastable argon atoms (Ar* 3P2) polarized in spin (M = +2) and ground-state Ar atoms from a nozzle beam is studied by means of a time-of-flight technique. A wide range of metastable atom velocities in the laboratory frame (275 m s-1 down to 50 m s-1) is obtained by use of a Zeeman slower, the counter-propagating laser beam of which is locked in frequency onto the 3P2-3D3 closed transition (λ = 811.5 nm). The accessible centre-of-mass energy range (8-27 meV) has not been explored so far, to our knowledge. Calculations based upon existing interatomic potentials of 2g and 2u symmetries are in reasonable agreement with experiment.

  1. Scaling of free-ranging primate energetics with body mass predicts low energy expenditure in humans.

    Science.gov (United States)

    Simmen, Bruno; Darlu, Pierre; Hladik, Claude Marcel; Pasquet, Patrick

    2015-01-01

    Studies of how a mammal's daily energy expenditure scales with its body mass suggest that humans, whether Westerners, agro-pastoralists, or hunter-gatherers, all have much lower energy expenditures for their body mass than other mammals. However, non-human primates also differ from other mammals in several life history traits suggestive of low energy use. Judging by field metabolic rates of free-ranging strepsirhine and haplorhine primates with different lifestyle and body mass, estimated using doubly labeled water, primates have lower energy expenditure than other similar-sized eutherian mammals. Daily energy expenditure in humans fell along the regression line of non-human primates. The results suggest that thrifty energy use could be an ancient strategy of primates. Although physical activity is a major component of energy balance, our results suggest a need to revise the basis for establishing norms of energy expenditure in modern humans. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Beam Energy Measurement by Resonant Depolarization Method at VEPP-4M

    CERN Document Server

    Blinov, V E; Kaminskiy, V V; Kudryavtsev, V N; Nikitin, S A; Nikolaev, I B; Shekhtman, L I

    2017-01-01

    Experiments on high precision mass measurement of particles require precise beam energy calibration. The most accurate method of beam energy measurement is the resonant depolarization technique. This article describes the beam energy measurement at the VEPP-4M storage ring using this method together with a Touschek polarimeter. The accuracy achieved is about 10−6. More than thousand energy calibrations were used in the KEDR detector for the precise experiments on the measurement of J/ψ, ψ(2S), ψ(3770), D+, D0 meson and τ lepton masses.

  3. Combined production of free-range pigs and energy crops – animal behaviour and crop damages

    DEFF Research Database (Denmark)

    Horsted, Klaus; Kongsted, Anne Grete; Jørgensen, Uffe

    2012-01-01

    Intensive free-range pig production on open grasslands has disadvantages in that it creates nutrient hotspots and little opportunity for pigs to seek shelter from the sun. Combining a perennial energy crop and pig production might benefit the environment and animal welfare because perennial energy...

  4. Photonic effects on the Förster resonance energy transfer efficiency

    NARCIS (Netherlands)

    Rabouw, Freddy T.; Den Hartog, Stephan A.; Senden, Tim; Meijerink, A

    2014-01-01

    Förster resonance energy transfer (ET) between luminescent species is applied in bio-imaging, lighting and photovoltaics, and has an important role in photosynthesis. However, the fundamental question of whether ET rates and efficiencies can be tuned by the photonic environment remains under debate.

  5. Studying DNA-protein interactions with single-molecule Förster resonance energy transfer

    NARCIS (Netherlands)

    Farooq, S.; Fijen, C.; Hohlbein, J.C.

    2014-01-01

    Single-molecule Förster resonance energy transfer (smFRET) has emerged as a powerful tool for elucidating biological structure and mechanisms on the molecular level. Here, we focus on applications of smFRET to study interactions between DNA and enzymes such as DNA and RNA polymerases. SmFRET, used

  6. Toward dynamic structural biology : Two decades of single-molecule Förster resonance energy transfer

    NARCIS (Netherlands)

    Lerner, Eitan; Cordes, Thorben; Ingargiola, Antonino; Alhadid, Yazan; Chung, SangYoon; Michalet, Xavier; Weiss, Shimon

    2018-01-01

    Classical structural biology can only provide static snapshots of biomacromolecules. Single-molecule Förster resonance energy transfer (smFRET) paved the way for studying dynamics in macromolecular structures under biologically relevant conditions. Since its first implementation in 1996, smFRET

  7. Förster resonance energy transfer by formation of a mechanically interlocked [2]rotaxane

    NARCIS (Netherlands)

    Ogoshi, T.; Yamafuji, D.; Yamagishi, T.; Brouwer, A.M.

    2013-01-01

    A[2]rotaxane has been constructed from a di-pyrene appended pillar[5]arene wheel, a pyridinium axle, and a perylene stopper. It shows efficient Forster resonance energy transfer from pyrene to perylene by formation of a mechanically interlocked [2]rotaxane.

  8. Förster resonance energy transfer rate in any dielectric nanophotonic medium with weak dispersion

    NARCIS (Netherlands)

    Wubs, M.; Vos, Willem L.

    2016-01-01

    Motivated by the ongoing debate about nanophotonic control of Förster resonance energy transfer (FRET), notably by the local density of optical states (LDOS), we study FRET and spontaneous emission in arbitrary nanophotonic media with weak dispersion and weak absorption in the frequency overlap

  9. Continuous-flow protease assay based on fluorescence resonance energy transfer

    NARCIS (Netherlands)

    Hirata, J.; Ariese, F.; Gooijer, C.; Irth, H.

    2003-01-01

    A homogeneous continuous-flow assay using fluorescence resonance energy transfer (FRET) for detection was developed to measure the hydrolysis of HIV Protease Substrate 1 (to which two choromophores, EDANS and DABCYL are covalently attached) by a protease (e.g. Subtilisin Carlsberg) and the influence

  10. Luciferase-Rose Bengal conjugates for singlet oxygen generation by bioluminescence resonance energy transfer.

    Science.gov (United States)

    Kim, Seonghoon; Jo, HyeongChan; Jeon, Mijeong; Choi, Myung-Gyu; Hahn, Sei Kwang; Yun, Seok-Hyun

    2017-04-20

    Conjugates of Rose Bengal and Renilla luciferase generated singlet oxygen upon binding with coelenterazine via bioluminescence resonance energy transfer (BRET). Since the applications of conventional PDT have been limited to superficial lesions due to the limited light penetration in tissue, BRET activated PDT which does not require external light illumination may overcome the limitations of conventional PDT.

  11. Power Take-Off with Integrated Resonator for Energy Extraction from Linear Motions

    DEFF Research Database (Denmark)

    2014-01-01

    resonate with the waves. The invention relates to the field of energy-harvesting from energy sources, where the energy-harvesting requires the extraction of energy from slow and often irregular reciprocating motion of bodies. The present invention relates to a wave power apparatus for converting power...... of sea or ocean waves into useful energy, such as electricity. The invention relates to the control and operation of a magnetic gear based motor/generator system. The invention provides a high force density electric powered linear actuator.......The invention relates to a magnetic gear for converting linear motion into rotational motion and vice versa. The present invention converts slow linear irregular oscillating motion of wave energy devices into torque on a high speed shaft for powering a generator while making the wave energy device...

  12. Carbon quantum dots as fluorescence resonance energy transfer sensors for organophosphate pesticides determination.

    Science.gov (United States)

    Wu, Xiaoli; Song, Yang; Yan, Xu; Zhu, Chengzhou; Ma, Yongqiang; Du, Dan; Lin, Yuehe

    2017-08-15

    Carbon quantum dots (CQDs) obtained from natural organics attract significant attention due to the abundance of carbon sources, varieties of heteroatom doping (such as N, S, P) and good biocompatibility of precursor. In this study, tunable fluorescence emission CQDs originated from chlorophyll were synthesized and characterized. The fluorescence emission can be effectively quenched by gold nanoparticles (Au NPs) via fluorescence resonance energy transfer (FRET). Thiocholine, which was produced from acetylthiocholine (ATC) by the hydrolysis of butyrylcholinesterase (BChE), could cause the aggregation of Au NPs and the corresponding recovery of FRET-quenched fluorescence emission. The catalytic activity of BChE could be irreversibly inhibited by organophosphorus pesticides (OPs), thus, the recovery effect was reduced. By evaluating the fluorescence emission intensity of CQDs, a FRET-based sensing platform for OPs determination was established. Paraoxon was studied as an example of OPs. The sensing platform displayed a linear relationship with the logarithm of the paraoxon concentrations in the range of 0.05-50μgL-1 and the limit of detection (LOD) was 0.05μgL-1. Real sample study in tap and river water revealed that this sensing platform was repeatable and accurate. The results indicate that the OP sensor is promising for applications in food safety and environmental monitoring. Copyright © 2017. Published by Elsevier B.V.

  13. Glucose Sensors Based on Microcapsules Containing an Orange/Red Competitive Binding Resonance Energy Transfer Assay

    Science.gov (United States)

    CHINNAYELKA, SWETHA; McSHANE, and MICHAEL J.

    2015-01-01

    Fluorescent sensing systems offer the potential for noninvasive monitoring with implantable devices, but they require carrier technologies that provide suitable immobilization, accessibility, and biocompatibility while maintaining adequate response characteristics. A recent development towards this goal is a highly specific and sensitive competitive binding assay for glucose using apo-glucose oxidase (apo-GOx) as the recognition element and dextran as the competing ligand; this has been demonstrated as a glucose sensor system by encapsulating the competitive binding assay in semipermeable microcapsule carriers. This paper describes the extension of this sensor design to longer wavelengths in an attempt to increase the applicability to in vivo monitoring. The glucose sensitivity of the tetramethylrhodamine isothiocyanate-dextran (TD) and cyanine Cy5-apo-GOx (CAG) complexes showed five to 10 times greater specificity for β-D-glucose over other sugars. Microcapsules loaded with TD/CAG complexes exhibited a linear, totally reversible response in the range of 0–720 mg/dL, with a sensitivity (percent change in intensity ratio) of 0.06%/(mg/dL). The decrease in sensitivity observed with the use of longer-wavelength dyes is most likely to be compensated with the deeper penetration of light and reduced tissue scattering. These findings imply that the encapsulation of sensing assay elements in microcapsules is a simple and translatable method for the fabrication of stable biosensors, and optimization of resonance energy transfer pairs and assay component preparation will further improve the response to approach clinically relevant performance. PMID:16800748

  14. Nanostructured biosensor for detecting glucose in tear by applying fluorescence resonance energy transfer quenching mechanism.

    Science.gov (United States)

    Chen, Longyi; Tse, Wai Hei; Chen, Yi; McDonald, Matthew W; Melling, James; Zhang, Jin

    2017-05-15

    In this paper, a nanostructured biosensor is developed to detect glucose in tear by using fluorescence resonance energy transfer (FRET) quenching mechanism. The designed FRET pair, including the donor, CdSe/ZnS quantum dots (QDs), and the acceptor, dextran-binding malachite green (MG-dextran), was conjugated to concanavalin A (Con A), an enzyme with specific affinity to glucose. In the presence of glucose, the quenched emission of QDs through the FRET mechanism is restored by displacing the dextran from Con A. To have a dual-modulation sensor for convenient and accurate detection, the nanostructured FRET sensors were assembled onto a patterned ZnO nanorod array deposited on the synthetic silicone hydrogel. Consequently, the concentration of glucose detected by the patterned sensor can be converted to fluorescence spectra with high signal-to-noise ratio and calibrated image pixel value. The photoluminescence intensity of the patterned FRET sensor increases linearly with increasing concentration of glucose from 0.03mmol/L to 3mmol/L, which covers the range of tear glucose levels for both diabetics and healthy subjects. Meanwhile, the calibrated values of pixel intensities of the fluorescence images captured by a handhold fluorescence microscope increases with increasing glucose. Four male Sprague-Dawley rats with different blood glucose concentrations were utilized to demonstrate the quick response of the patterned FRET sensor to 2µL of tear samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Determination of dihydralazine based on chemiluminescence resonance energy transfer of hollow carbon nanodots

    Science.gov (United States)

    Han, Suqin; Fan, Zheyan; Chen, Xiaoxia; Wu, Yunfang; Wang, Jianbo

    2017-08-01

    The famous weak chemiluminescence (CL) system of potassium permanganate and sodium bisulfite (KMnO4-HSO3-) was enhanced by the hollow fluorescent carbon nanodots (HCNs). The investigation of mechanism revealed that the enhanced CL was induced by the excited-state HCNs (HCNs*), which could be produced from the electron-transfer annihilation of positively charged HCNs (HCNsrad +) and negatively charged HCNs (HCNsrad -) as well as by CL resonance energy transfer (CRET) from excited SO2 (SO2*)/1O2 to HCNs. The dihydralazine sulfate (DHZS) had a diminishing effect on the CL of HCNs-KMnO4-HSO3- system due to the competitive consumption of rad O2-. Under the optimal conditions, the reduced CL signal with the concentration of DHZS was linear in the range of 1.0 × 10- 7-7.0 × 10- 5 mol/L with a detection limit of 3.0 × 10- 8 mol/L. The relative standard deviation for seven repeated determination of 5.0 × 10- 6 mol/L DHZS was 2.1%. The established method was applied to the determination of DHZS in pharmaceutical preparations, human urine and plasma samples with good precision and accuracy.

  16. Prospects for bioenergy use in Ghana using Long-range Energy Alternatives Planning model

    DEFF Research Database (Denmark)

    Kemausuor, Francis; Nygaard, Ivan; Mackenzie, Gordon A.

    2015-01-01

    that introducing bioenergy to the energy mix could reduce GHG (greenhouse gas) emissions by about 6 million tonnes CO2e by 2030, equivalent to a 14% reduction in a business-as-usual scenario. This paper advocates the use of second generation ethanol for transport, to the extent that it is economically exploitable......As Ghana's economy grows, the choice of future energy paths and policies in the coming years will have a significant influence on its energy security. A Renewable Energy Act approved in 2011 seeks to encourage the influx of renewable energy sources in Ghana's energy mix. The new legal framework...... biomass sources, through the production of biogas, liquid biofuels and electricity. Analysis was based on moderate and high use of bioenergy for transportation, electricity generation and residential fuel using the LEAP (Long-range Energy Alternatives Planning) model. Results obtained indicate...

  17. Energy Impacts of Effective Range Hood Use for all U.S. Residential Cooking

    Energy Technology Data Exchange (ETDEWEB)

    Logue, Jennifer M; Singer, Brett

    2014-06-01

    Range hood use during residential cooking is essential to maintaining good indoor air quality. However, widespread use will impact the energy demand of the U.S. housing stock. This paper describes a modeling study to determine site energy, source energy, and consumer costs for comprehensive range hood use. To estimate the energy impacts for all 113 million homes in the U.S., we extrapolated from the simulation of a representative weighted sample of 50,000 virtual homes developed from the 2009 Residential Energy Consumption Survey database. A physics-based simulation model that considered fan energy, energy to condition additional incoming air, and the effect on home heating and cooling due to exhausting the heat from cooking was applied to each home. Hoods performing at a level common to hoods currently in U.S. homes would require 19?33 TWh [69?120 PJ] of site energy, 31?53 TWh [110-190 PJ] of source energy; and would cost consumers $1.2?2.1 billion (U.S.$2010) annually in the U.S. housing stock. The average household would spend less than $15 annually. Reducing required airflow, e.g. with designs that promote better pollutant capture has more energy saving potential, on average, than improving fan efficiency.

  18. Long-range forecasts for the energy market - a case study

    Science.gov (United States)

    Hyvärinen, Otto; Mäkelä, Antti; Kämäräinen, Matti; Gregow, Hilppa

    2017-04-01

    We examined the feasibility of long-range forecasts of temperature for needs of the energy sector in Helsinki, Finland. The work was done jointly by Finnish Meteorological Institute (FMI) and Helen Ltd, the main Helsinki metropolitan area energy provider, and especially provider of district heating and cooling. Because temperatures govern the need of heating and cooling and, therefore, the energy demand, better long-range forecasts of temperature would be highly useful for Helen Ltd. Heating degree day (HDD) is a parameter that indicates the demand of energy to heat a building. We examined the forecasted monthly HDD values for Helsinki using UK Met Office seasonal forecasts with the lead time up to two months. The long-range forecasts of monthly HDD showed some skill in Helsinki in winter 2015-2016, especially if the very cold January is excluded.

  19. Broad-Range Electrically Tunable Plasmonic Resonances of a Multilayer Coaxial Nanohole Array with an Electroactive Polymer Wrapper.

    Science.gov (United States)

    Zhou, Ziwei; Yu, Ye; Sun, Ningwei; Möhwald, Helmuth; Gu, Panpan; Wang, Liyan; Zhang, Wei; König, Tobias A F; Fery, Andreas; Zhang, Gang

    2017-10-11

    Plasmonic assemblies featuring high sensitivity that can be readily shifted by external fields are the key for sensitive and versatile sensing devices. In this paper, a novel fast-responsive plasmonic nanocomposite composed of a multilayer nanohole array and a responsive electrochromic polymer is proposed with the plasmonic mode appearance vigorously cycled upon orthogonal electrical stimuli. In this nanocomposite, the coaxially stacked plasmonic nanohole arrays can induce multiple intense Fano resonances, which result from the crosstalk between a broad surface plasmon resonance (SPR) and the designed discrete transmission peaks with ultrahigh sensitivity; the polymer wrapper could provide the sensitive nanohole array with real-time-varied surroundings of refractive indices upon electrical stimuli. Therefore, a pronounced pure electroplasmonic shift up to 72 nm is obtained, which is the largest pure electrotuning SPR range to our knowledge. The stacked nanohole arrays here are also directly used as a working electrode, and they ensure sufficient contact between the working electrode (plasmonic structure) and the electroactive polymer, thus providing considerably improved response speed (within 1 s) for real-time sensing and switching.

  20. A Microbolometer System for Radiation Detection in the THz Frequency Range with a Resonating Cavity Fabricated in the CMOS Technology.

    Science.gov (United States)

    Sesek, Aleksander; Zemva, Andrej; Trontelj, Janez

    2018-02-14

    The THz sensors using microbolometers as a sensing element are reported as one of the most sensitive room-temperature THz detectors suitable for THz imaging and spectroscopic applications. Microbolometer detectors are usually fabricated using different types of the MEMS technology. The patent for the detection system presented in this paper describes a method for microbolometer fabrication using a standard CMOS technology with advanced micromachining techniques. The measured sensitivity of the sensors fabricated by the patented method is 1000 V/W at an optimal frequency and is determined by the performance of a double-dipole antenna and quarter-wavelength resonant cavity. The paper presents a patented method for fabrication of a microbolometer system for radiation detection in the THz frequency range (16). The method is divided into several stages regarding the current silicon micromachining process. Main stages are fabrication of supporting structures for micro bridge, creation of micro cavities and fabrication of Aluminum antenna and Titanium microbolometer. Additional method for encapsulation in the vacuum is described which additionally improves the performance of bolometer. The CMOS technology is utilized for fabrication as it is cost effective and provides the possibility of larger sensor systems integration with included amplification. At other wavelengths (e.g. IR region) thermistors are usually also the receivers with the sensor resistance change provoked by self-heating. In the THz region the energy is received by an antenna coupled to a thermistor. Depending on the specific application requirement, two types of the antenna were designed and used; a narrow-band dipole antenna and a wideband log-periodic antenna. With method described in the paper, the microbolometer detector reaches sensitivities up to 500 V/W and noise equivalent power (NEP) down to 10 pW/√Hz. Additional encapsulation in the vacuum improves its performance at least by a factor of 2

  1. Theoretical photoionization spectra in the UV photon energy range for a Mg-like Al{sup +} ion

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dae-Soung [e-Business Department, Kyonggi Institute of Technology, Siheung, Jungwang-Dong 2121-3, Kyonggi-Do 429-792 (Korea, Republic of); Kim, Young Soon [Department of Physics, Myongji University, San 38-2 Namdong, Cheoin-gu, Yongin, Kyonggi-Do 449-728 (Korea, Republic of)], E-mail: dskim@kinst.ac.kr

    2008-08-28

    In the present work, we report the photoionization cross sections of the Al{sup +} ion calculated for the photon energy range 20-26 eV and 30-50 eV. We have expanded our previous calculation (2007 J. Phys. Soc. Japan 76 014302) with an optimized admixture of the initial ground state 3s{sup 21}S and exited states 3s3p{sup 1,3}P, 3s3d{sup 1,3}D and 3s4s{sup 1,3}S, and obtained significantly improved predictions for the main background and autoionizing resonance structures of the reported experimental spectra. The absolute measurements of the photoionization cross sections of the Al{sup +} ion in these energy ranges have been performed by West et al (2001 Phys. Rev. A 63 052719), and they reported that the prominent peaks around 21 eV were attributed to the effects of the significant influence of the small fraction of the fourth-order radiation with energies around 84 eV from the synchrotron source. In our previous work, the main shape for these cross sections was calculated assuming an admixture of initial 3s{sup 21}S and 3s3p{sup 3}P states, only with a rough overall estimate for the experimental spectra in the photon energy range 20-26 eV, and without these peaks around 21 eV. The report of the experimental assignment attributes these peaks to the excitation of a 2p electron from the core. However, our present results with the new admixture reveal similar peaks without considering the possibility of the core excitation.

  2. [Fluorescence resonance energy transfer between gentamycin and water-soluble CdTe QDs].

    Science.gov (United States)

    Li, Jin-Gui; Zhu, Kui; Xu, Fei; Jiang, Hai-Yang; Ding, Shuang-Yang

    2009-11-01

    The water-soluble CdTe quantum dots (QDs) were prepared by using mercaptopropionic acid (MPA) as stabilizer in the aqueous system. Fluorescence resonance energy transfer (FRET) system was constructed between gentamycin (acceptor) and water-soluble CdTe QDs (donor). The maximal emission wavelength was 690 nm, and the line width of the fluorescence spectrum was very narrow (with the full width at half-maximum about 10 nm) and symmetric. The transfer of resonance energy from the CdTe QDs to gentamycin (GT) resulted in the fluorescence quenching of the QDs, corresponding to the increase in the concentration of GT. Several factors that impacted the fluorescence spectra of the FRET system, such as the excitation wavelength (305-425 nm), pH(5.0-11.0), ions (0-0.1 mmol x L(-1) PBS; 0-0.5 mmol x L(-1) NaCl), time (1-120 min), temperature (5-50 degrees C), and concentration of GT (2-80 mg x L(-1)), were investigated and refined. The linear ranges of GT concentration were 2-20 mg x L(-1), r = 0.986 7. Fourier transform infrared spectroscopy (FTIR) and high-performance liquid chromatography (HPLC) were used for confirming the chemical construction and relative specificity, respectively. The results indicated that sulfur and oxygen atoms in MPA molecules took part in coordination with rich Cd2+ on the surface of the nanoparticles. Meanwhile the results also demonstrated that the hydrogen bond between carboxyl of mercaptopropionic acid on the surface of quantum dots and amidocyanogen of GT mainly contributes to combining CdTe with GT. The combination ratio between GT and CdTe QDs is 0.35 to 1.0 according to HPLC. GT as an enhancement has first been applied to the determination of the bovine serum albumin (BSA) labeled with CdTe QDs, and the fluorescence intensity of the labeled BSA with GT is 6 times higher than the control. The proposed method might offer an attractive potential for use in future, because it is sensitive and rapid.

  3. Magnetic Separation-Assistant Fluorescence Resonance Energy Transfer Inhibition for Highly Sensitive Probing of Nucleolin.

    Science.gov (United States)

    Li, Yan-Ran; Liu, Qian; Hong, Zhangyong; Wang, He-Fang

    2015-12-15

    For the widely used "off-on" fluorescence (or phosphorescence) resonance energy transfer (FRET or PRET) system, the separation of donors and acceptors species was vital for enhancing the sensitivity. To date, separation of free donors from FRET/PRET inhibition systems was somewhat not convenient, whereas separation of the target-induced far-between acceptors has hardly been reported yet. We presented here a novel magnetic separation-assistant fluorescence resonance energy transfer (MS-FRET) inhibition strategy for highly sensitive detection of nucleolin using Cy5.5-AS1411 as the donor and Fe3O4-polypyrrole core-shell (Fe3O4@PPY) nanoparticles as the NIR quenching acceptor. Due to hydrophobic interaction and π-π stacking of AS1411 and PPY, Cy5.5-AS1411 was bound onto the surface of Fe3O4@PPY, resulting in 90% of fluorescence quenching of Cy5.5-AS1411. Owing to the much stronger specific interaction of AS1411 and nucleolin, the presence of nucleolin could take Cy5.5-AS1411 apart from Fe3O4@PPY and restore the fluorescence of Cy5.5-AS1411. The superparamagnetism of Fe3O4@PPY enabled all separations and fluorescence measurements complete in the same quartz cell, and thus allowed the convenient but accurate comparison of the sensitivity and fluorescence recovery in the cases of separation or nonseparation. Compared to nonseparation FRET inhibition, the separation of free Cy5.5-AS1411 from Cy5.5-AS1411-Fe3O4@PPY solution (the first magnetic separation, MS-1) had as high as 25-fold enhancement of the sensitivity, whereas further separation of the nucleolin-inducing far-between Fe3O4@PPY from the FRET inhibition solution (the second magnetic separation, MS-2) could further enhance the sensitivity to 35-fold. Finally, the MS-FRET inhibition assay displayed the linear range of 0.625-27.5 μg L(-1) (8.1-359 pM) and detection limit of 0.04 μg L(-1) (0.05 pM) of nucleolin. The fluorescence intensity recovery (the percentage ratio of the final restoring fluorescence intensity

  4. Time-of-flight electron spectrometer for a broad range of kinetic energies

    Energy Technology Data Exchange (ETDEWEB)

    Kothe, Alexander; Metje, Jan; Wilke, Martin; Moguilevski, Alexandre; Engel, Nicholas; Al-Obaidi, Ruba; Richter, Clemens; Golnak, Ronny; Kiyan, Igor Yu.; Aziz, Emad F. [Joint Ultrafast Dynamics Lab in Solutions and at Interfaces (JULiq), Helmholtz-Zentrum Berlin fuer Materialien und Energie (HZB), Albert-Einstein-Str. 15, 12489 Berlin (Germany) and Freie Universitaet Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin (Germany)

    2013-02-15

    A newly constructed time-of-flight electron spectrometer of the magnetic bottle type is characterized for electron detection in a broad range of kinetic energies. The instrument is designed to measure the energy spectra of electrons generated from liquids excited by strong laser fields and photons in the range of extreme ultra violet and soft X-rays. Argon inner shell electrons were recorded to calibrate the spectrometer and investigate its characteristics, such as energy resolution and collection efficiency. Its energy resolution {Delta}E/E of 1.6% allows resolving the Ar 2p spin orbit structure at kinetic energies higher than 100 eV. The collection efficiency is determined and compared to that of the spectrometer in its field-free configuration.

  5. A Wireless Magnetic Resonance Energy Transfer System for Micro Implantable Medical Sensors

    Directory of Open Access Journals (Sweden)

    Tianyang Yang

    2012-07-01

    Full Text Available Based on the magnetic resonance coupling principle, in this paper a wireless energy transfer system is designed and implemented for the power supply of micro-implantable medical sensors. The entire system is composed of the in vitro part, including the energy transmitting circuit and resonant transmitter coils, and in vivo part, including the micro resonant receiver coils and signal shaping chip which includes the rectifier module and LDO voltage regulator module. Transmitter and receiver coils are wound by Litz wire, and the diameter of the receiver coils is just 1.9 cm. The energy transfer efficiency of the four-coil system is greatly improved compared to the conventional two-coil system. When the distance between the transmitter coils and the receiver coils is 1.5 cm, the transfer efficiency is 85% at the frequency of 742 kHz. The power transfer efficiency can be optimized by adding magnetic enhanced resonators. The receiving voltage signal is converted to a stable output voltage of 3.3 V and a current of 10 mA at the distance of 2 cm. In addition, the output current varies with changes in the distance. The whole implanted part is packaged with PDMS of excellent biocompatibility and the volume of it is about 1 cm3.

  6. A wireless magnetic resonance energy transfer system for micro implantable medical sensors.

    Science.gov (United States)

    Li, Xiuhan; Zhang, Hanru; Peng, Fei; Li, Yang; Yang, Tianyang; Wang, Bo; Fang, Dongming

    2012-01-01

    Based on the magnetic resonance coupling principle, in this paper a wireless energy transfer system is designed and implemented for the power supply of micro-implantable medical sensors. The entire system is composed of the in vitro part, including the energy transmitting circuit and resonant transmitter coils, and in vivo part, including the micro resonant receiver coils and signal shaping chip which includes the rectifier module and LDO voltage regulator module. Transmitter and receiver coils are wound by Litz wire, and the diameter of the receiver coils is just 1.9 cm. The energy transfer efficiency of the four-coil system is greatly improved compared to the conventional two-coil system. When the distance between the transmitter coils and the receiver coils is 1.5 cm, the transfer efficiency is 85% at the frequency of 742 kHz. The power transfer efficiency can be optimized by adding magnetic enhanced resonators. The receiving voltage signal is converted to a stable output voltage of 3.3 V and a current of 10 mA at the distance of 2 cm. In addition, the output current varies with changes in the distance. The whole implanted part is packaged with PDMS of excellent biocompatibility and the volume of it is about 1 cm(3).

  7. Performance optimization of total momentum filtering double-resonance energy selective electron heat pump

    Science.gov (United States)

    Ding, Ze-Min; Chen, Lin-Gen; Ge, Yan-Lin; Sun, Feng-Rui

    2016-04-01

    A theoretical model for energy selective electron (ESE) heat pumps operating with two-dimensional electron reservoirs is established in this study. In this model, a double-resonance energy filter operating with a total momentum filtering mechanism is considered for the transmission of electrons. The optimal thermodynamic performance of the ESE heat pump devices is also investigated. Numerical calculations show that the heating load of the device with two resonances is larger, whereas the coefficient of performance (COP) is lower than the ESE heat pump when considering a single-resonance filter. The performance characteristics of the ESE heat pumps in the total momentum filtering condition are generally superior to those with a conventional filtering mechanism. In particular, the performance characteristics of the ESE heat pumps considering a conventional filtering mechanism are vastly different from those of a device with total momentum filtering, which is induced by extra electron momentum in addition to the horizontal direction. Parameters such as resonance width and energy spacing are found to be associated with the performance of the electron system.

  8. Harvesting wind energy to detect weak signals using mechanical stochastic resonance

    Science.gov (United States)

    Breen, Barbara J.; Rix, Jillian G.; Ross, Samuel J.; Yu, Yue; Lindner, John F.; Mathewson, Nathan; Wainwright, Elliot R.; Wilson, Ian

    2016-12-01

    Wind is free and ubiquitous and can be harnessed in multiple ways. We demonstrate mechanical stochastic resonance in a tabletop experiment in which wind energy is harvested to amplify weak periodic signals detected via the movement of an inverted pendulum. Unlike earlier mechanical stochastic resonance experiments, where noise was added via electrically driven vibrations, our broad-spectrum noise source is a single flapping flag. The regime of the experiment is readily accessible, with wind speeds ˜20 m/s and signal frequencies ˜1 Hz. We readily obtain signal-to-noise ratios on the order of 10 dB.

  9. Unusual energy shifts in resonant photoemission spectra of organic model molecules.

    Science.gov (United States)

    Peisert, H; Biswas, I; Zhang, L; Schuster, B-E; Casu, M B; Haug, A; Batchelor, D; Knupfer, M; Chassé, T

    2009-05-21

    We study the electronic structure of zinc phthalocyanine (ZnPc) and 1,4-octa-decyl substituted zinc phthalocyanine [(Dec)(8)PcZn] thin films (approximately 6-15 nm) using resonant photoemission spectroscopy and X-ray absorption spectroscopy (XAS) at room temperature and at liquid He temperature. From XAS we conclude that the probability amplitude of the lowest unoccupied molecular orbital is located predominantly at the inner C and N atoms of the molecules. Nonlinear energy shifts in resonant photoemission were observed; large shifts are explained by reduced electrical conductivity of inhomogeneously oriented molecules.

  10. Broadband vibration energy harvesting by application of stochastic resonance from rotational environments

    Science.gov (United States)

    Zhang, Y.; Zheng, R.; Kaizuka, T.; Su, D.; Nakano, K.; Cartmell, M. P.

    2015-11-01

    A model for energy harvesting from a rotating automotive tyre is suggested in which the principle of stochastic resonance is advantageously exploited. A bistable response characteristic is obtained by recourse a small harvester comprising a magnetically repellant configuration in which an instrumented cantilever beam can flip between two physical response states when suitably excited by the rotation of a car wheel into which it is fitted. The rotation of the wheel creates a periodic modulation which enables stochastic resonance to take place and as a consequence of this for energy to be harvested from road noise transmitted through the tyre. An optimised mathematical model of the system is presented based on a series of experimental tests and it is shown that a ten-fold increase in harvested energy over a comparable monostable case is feasible. The suggested application for this harvester is to provide electrical power for a tyre pressure monitoring system.

  11. Energy harvesting from coherent resonance of horizontal vibration of beam excited by vertical base motion

    Energy Technology Data Exchange (ETDEWEB)

    Lan, C. B.; Qin, W. Y. [Department of Engineering Mechanics, Northwestern Polytechnical University, Xi' an 710072 (China)

    2014-09-15

    This letter investigates the energy harvesting from the horizontal coherent resonance of a vertical cantilever beam subjected to the vertical base excitation. The potential energy of the system has two symmetric potential wells. So, under vertical excitation, the system can jump between two potential wells, which will lead to the large vibration in horizontal direction. Two piezoelectric patches are pasted to harvest the energy. From experiment, it is found that the vertical excitation can make the beam turn to be bistable. The system can transform vertical vibration into horizontal vibration of low frequency when excited by harmonic motion. The horizontal coherence resonance can be observed when excited by a vertical white noise. The corresponding output voltages of piezoelectric films reach high values.

  12. Probing resonant energy transfer in collisions of ammonia with Rydberg helium atoms by microwave spectroscopy

    Science.gov (United States)

    Zhelyazkova, V.; Hogan, S. D.

    2017-12-01

    We present the results of experiments demonstrating the spectroscopic detection of Förster resonance energy transfer from NH3 in the X1A1 ground electronic state to helium atoms in 1sns 3S1 Rydberg levels, where n = 37 and n = 40. For these values of n, the 1sns 3S1 → 1snp 3PJ transitions in helium lie close to resonance with the ground-state inversion transitions in NH3 and can be tuned through resonance using electric fields of less than 10 V/cm. In the experiments, energy transfer was detected by direct state-selective electric field ionization of the 3S1 and 3PJ Rydberg levels and by monitoring the population of the 3DJ levels following pulsed microwave transfer from the 3PJ levels. Detection by microwave spectroscopic methods represents a highly state selective, low-background approach to probing the collisional energy transfer process and the environment in which the atom-molecule interactions occur. The experimentally observed electric-field dependence of the resonant energy transfer process, probed both by direct electric field ionization and by microwave transfer, agrees well with the results of calculations performed using a simple theoretical model of the energy transfer process. For measurements performed in zero electric field with atoms prepared in the 1s40s 3S1 level, the transition from a regime in which a single energy transfer channel can be isolated for detection to one in which multiple collision channels begin to play a role has been identified as the NH3 density was increased.

  13. Plasmonic resonances in hybrid systems of aluminum nanostructured arrays and few layer graphene within the UV–IR spectral range

    Science.gov (United States)

    González-Campuzano, R.; Saniger, J. M.; Mendoza, D.

    2017-11-01

    The size-controllable and ordered Al nanocavities and nanodomes arrays were synthesized by electrochemical anodization of aluminum using phosphoric acid, citric acid and mixture both acids. Few layer graphene (FLG) was transferred directly on top of Al nanostructures and their morphology were evaluated by scanning electron microscopy. The interaction between FLG and the plasmonic properties of Al nanostructures arrays were investigated based on specular reflectivity in the ultraviolet–visible–infrared range and Raman spectroscopy. We found that their optical reflectivity was dramatically reduced as compared with unstructured Al. At the same time pronounced reflectivity dips were detectable in the 200–896 nm wavelength range, which were ascribed to plasmonic resonances. The plasmonic properties of these nanostructures do not exhibit evident changes by the presence of FLG in the UV–vis range of the electromagnetic spectrum. By contrast, the surface-enhanced Raman spectroscopy of FLG was observed in nanocavities and nanodomes structures that result in an intensity increase of the characteristic G and 2D bands of FLG induced by the plasmonic properties of Al nanostructures.

  14. Nuclear Symmetry Energy: constraints from Giant Quadrupole Resonances and Parity Violating Electron Scattering

    Directory of Open Access Journals (Sweden)

    Roca-Maza X.

    2014-03-01

    Full Text Available Experimental and theoretical efforts are being devoted to the study of observables that can shed light on the properties of the nuclear symmetry energy. We present our new results on the excitation energy [1] and polarizability of the Isovector Giant Quadrupole Resonance (IVGQR, which has been the object of new experimental investigation[2]. We also present our theoretical analysis on the parity violating asymmetry at the kinematics of the Lead Radius Experiment (PREx [3] and highlight its relation with the density dependence of the symmetry energy [4].

  15. Research into energy absorption of liquid cabin subjected to close-range explosion

    Directory of Open Access Journals (Sweden)

    LI Siyu

    2017-01-01

    Full Text Available In order to study the energy absorption of different parts of a liquid cabin under a close-range explosion, a fluid-structure coupling model is built on the basis of experiments, and the deformation of the bulkhead and energy absorption ratio of different parts of the liquid cabin are analyzed, in which the influence of the water, bulkhead thickness ratio and water thickness are also discussed. The results show that the existence of a liquid medium can change the energy absorption model of a cabin. The total energy absorption is mainly affected by the front bulkhead thickness and water thickness, and alterations to the bulkhead thickness ratio or water thickness can also affect the deformation model of the bulkhead and energy absorption ratio of different parts of the cabin. A logical explanation of the energy absorption mechanisms of the liquid cabin is proposed, and some useful suggestions for designs are given.

  16. Experimental characterization of cantilever-type piezoelectric generator operating at resonance for vibration energy harvesting

    Energy Technology Data Exchange (ETDEWEB)

    Montanini, Roberto, E-mail: rmontanini@unime.it; Quattrocchi, Antonino, E-mail: aquattrocchi@unime.it [University of Messina, Dept. of Engineering, Contrada di Dio, Messina (Italy)

    2016-06-28

    A cantilever-type resonant piezoelectric generator (RPG) has been designed by gluing a PZT patch working in d{sub 31} mode onto a glass fibre reinforced composite cantilever beam with a discrete mass applied on its free end. The electrical and dynamic behaviour of the RPG prototype has been investigated by carrying out laboratory tests aimed to assess the effect of definite design parameters, specifically the electric resistance load and the excitation frequency. Results showed that an optimum resistance load exists, at which power generation is maximized. Moreover, it has been showed that power generation is strongly influenced by the vibration frequency highlighting that, at resonance, output power can be increased by more than one order of magnitude. Possible applications include inertial resonant harvester for energy recovery from vibrating machines, sea waves or wind flux and self-powering of wireless sensor nodes.

  17. A resonant electromagnetic vibration energy harvester for intelligent wireless sensor systems

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Jing, E-mail: jingqiu@cqu.edu.cn; Wen, Yumei; Li, Ping; Liu, Xin; Chen, Hengjia; Yang, Jin [Sensors and Instruments Research Center, College of Optoelectronic Engineering, Chongqing University, Chongqing 400044 (China)

    2015-05-07

    Vibration energy harvesting is now receiving more interest as a means for powering intelligent wireless sensor systems. In this paper, a resonant electromagnetic vibration energy harvester (VEH) employing double cantilever to convert low-frequency vibration energy into electrical energy is presented. The VEH is made up of two cantilever beams, a coil, and magnetic circuits. The electric output performances of the proposed electromagnetic VEH have been investigated. With the enhancement of turns number N, the optimum peak power of electromagnetic VEH increases sharply and the resonance frequency deceases gradually. When the vibration acceleration is 0.5 g, we obtain the optimum output voltage and power of 9.04 V and 50.8 mW at frequency of 14.9 Hz, respectively. In a word, the prototype device was successfully developed and the experimental results exhibit a great enhancement in the output power and bandwidth compared with other traditional electromagnetic VEHs. Remarkably, the proposed resonant electromagnetic VEH have great potential for applying in intelligent wireless sensor systems.

  18. Harnessing Big-Data for Estimating the Energy Consumption and Driving Range of Electric Vehicles

    DEFF Research Database (Denmark)

    Fetene, Gebeyehu Manie; Prato, Carlo Giacomo; Kaplan, Sigal

    This study analyses the driving range and investigates the factors affecting the energy consumption rate of fully-battery electric vehicles under real-world driving patterns accounting for weather condition, drivers’ characteristics, and road characteristics. Four data sources are used: (i) up...... to six months driving pattern data collected from 741 drivers, (ii) drivers’ characteristics; (iii) road characteristics; (iv) weather data. We found that the real-world driving range of BEVs is highly sensitive to driving pattern and weather variables. The most important determinants of energy......-effects econometrics model used in this paper predicts that the energy saving speed of driving is between 45 and 56 km/h. In addition to the contribution to the literature about energy efficiency of electric vehicles, the findings from this study enlightens consumers to choose appropriate cars that suit their travel...

  19. Multi-Group Library Generation with Explicit Resonance Interference Using Continuous Energy Monte Carlo Calculation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ho Jin; Cho, Jin Young [KAERI, Daejeon (Korea, Republic of); Kim, Kang Seog [Oak Ridge National Laboratory, Oak Ridge (United States); Hong, Ser Gi [Kyung Hee University, Yongin (Korea, Republic of)

    2016-05-15

    In this study, multi-group cross section libraries for the DeCART code were generated using a new procedure. The new procedure includes generating the RI tables based on the MC calculations, correcting the effective fission product yield calculations, and considering most of the fission products as resonant nuclides. KAERI (Korea Atomic Energy Research Institute) has developed the transport lattice code KARMA (Kernel Analyzer by Ray-tracing Method for fuel Assembly) and DeCART (Deterministic Core Analysis based on Ray Tracing) for a multi-group neutron transport analysis of light water reactors (LWRs). These codes adopt the method of characteristics (MOC) to solve the multi-group transport equation and resonance fixed source problem, the subgroup and the direct iteration method with resonance integral tables for resonance treatment. With the development of the DeCART and KARMA code, KAERI has established its own library generation system for a multi-group transport calculation. In the KAERI library generation system, the multi-group average cross section and resonance integral (RI) table are generated and edited using PENDF (point-wise ENDF) and GENDF (group-wise ENDF) produced by the NJOY code. The new method does not need additional processing because the MC method can handle any geometry information and material composition. In this study, the new method is applied to the dominant resonance nuclide such as U{sup 235} and U{sup 238} and the conventional method is applied to the minor resonance nuclides. To examine the newly generated multi-group cross section libraries, various benchmark calculations such as pin-cell, FA, and core depletion problem are performed and the results are compared with the reference solutions. Overall, the results by the new method agree well with the reference solution. The new procedure based on the MC method were verified and provided the multi-group library that can be used in the SMR nuclear design analysis.

  20. Three new low-energy resonances in the $^{22}$Ne(p,$\\gamma$)$^{23}$Na reaction

    CERN Document Server

    Cavanna, F; Aliotta, M; Anders, M; Bemmerer, D; Best, A; Böltzig, A; Broggini, C; Bruno, C G; Caciolli, A; Corvisiero, P; Davinson, T; di Leva, A; Elekes, Z; Ferraro, F; Formicola, A; Fülöp, Zs; Gervino, G; Guglielmetti, A; Gustavino, C; Gyürky, Gy; Imbriani, G; Junker, M; Menegazzo, R; Mossa, V; Pantaleo, F R; Prati, P; Scott, D A; Somorjai, E; Straniero, O; Strieder, F; Szücs, T; Takács, M P; Trezzi, D

    2015-01-01

    The $^{22}$Ne(p,$\\gamma$)$^{23}$Na reaction takes part in the neon-sodium cycle of hydrogen burning. This cycle affects the synthesis of the elements between $^{20}$Ne and $^{27}$Al in asymptotic giant branch stars and novae. The $^{22}$Ne(p,$\\gamma$)$^{23}$Na reaction rate is very uncertain because of a large number of unobserved resonances lying in the Gamow window. At proton energies below 400\\,keV, only upper limits exist in the literature for the resonance strengths. Previous reaction rate evaluations differ by large factors. In the present work, the first direct observations of the $^{22}$Ne(p,$\\gamma$)$^{23}$Na resonances at 156.2, 189.5, and 259.7\\,keV are reported. Their resonance strengths have been derived with 2-7\\% uncertainty. In addition, upper limits for three other resonances have been greatly reduced. Data were taken using a windowless $^{22}$Ne gas target and high-purity germanium detectors at the Laboratory for Underground Nuclear Astrophysics in the Gran Sasso laboratory of the National I...

  1. Experimental exclusion of neutral resonances in Bhabha scattering at MeV energies

    Science.gov (United States)

    Tsertos, H.; Kienle, P.; Judge, S. M.; Schreckenbach, K.

    1991-08-01

    Using an active-shadow technique and a monoenergetic e + beam at the high-flux reactor of ILL, we pursued the search for long-lived (> 5 × 10 -13 s) neutral resonances that could be formed in e +e - scattering around an invariant mass of 1.8 MeV/ c2. With a significantly improved experimental sensitivity we found no evidence for such a narrow resonance decaying into e +e - pairs. From our whole investigations, the model-independent stringent lower limits (95% CL) of 5 × 10 -11 s and 1 × 10 -10 s can be set on the lifetime of hypothetical J = 0 and J = 1 resonances, respectively. Our conclusive results rule out theoretical proposals that involve neutral free particles or e +e - bound states in this mass range, as an explanation of the e +e - lines observed at GSI.

  2. Conversion efficiency of an energy harvester based on resonant tunneling through quantum dots with heat leakage.

    Science.gov (United States)

    Kano, Shinya; Fujii, Minoru

    2017-03-03

    We study the conversion efficiency of an energy harvester based on resonant tunneling through quantum dots with heat leakage. Heat leakage current from a hot electrode to a cold electrode is taken into account in the analysis of the harvester operation. Modeling of electrical output indicates that a maximum heat leakage current is not negligible because it is larger than that of the heat current harvested into electrical power. A reduction of heat leakage is required in this energy harvester in order to obtain efficient heat-to-electrical conversion. Multiple energy levels of a quantum dot can increase the output power of the harvester. Heavily doped colloidal semiconductor quantum dots are a possible candidate for a quantum-dot monolayer in the energy harvester to reduce heat leakage, scaling down device size, and increasing electrical output via multiple discrete energy levels.

  3. An energetic measure of aromaticity and antiaromaticity based on the Pauling-Wheland resonance energies.

    Science.gov (United States)

    Mo, Yirong; von Ragué Schleyer, Paul

    2006-02-20

    Various criteria based on geometric, energetic, magnetic, and electronic properties are employed to delineate aromatic and antiaromatic systems. The recently proposed block-localized wave function (BLW) method evaluates the original Pauling-Wheland adiabatic resonance energy (ARE), defined as the energy difference between the real conjugated system and the corresponding virtual most stable resonance structure. The BLW-derived ARE of benzene is 57.5 kcal mol(-1) with the 6-311+G** basis set. Kistiakowsky's historical experimental evaluation of the stabilization energy of benzene (36 kcal mol(-1)), based on heats of hydrogenation, seriously underestimates this quantity due to the neglect of the partially counterbalancing hyperconjugative stabilization of cyclohexene, employed as the reference olefin (three times) in Kistiakowsky's evaluation. Based instead on the bond-separation-energy reaction involving ethene, which has no hyperconjugation, as well as methane and ethane, the experimental resonance energy of benzene is found to be 65.0 kcal mol(-1). We derived the "extra cyclic resonance energy" (ECRE) to characterize and measure the extra stabilization (aromaticity) of conjugated rings. ECRE is the difference between the AREs of a fully cyclically conjugated compound and an appropriate model with corresponding, but interrupted (acyclic) conjugation. Based on 1,3,5-hexatriene, which also has three double bonds, the ECRE of benzene is 36.7 kcal mol(-1), whereas based on 1,3,5,7-octatetraene, which has three diene conjugations, the ECRE of benzene is 25.7 kcal mol(-1). Computations on a series of aromatic, nonaromatic, and antiaromatic five-membered rings validate the BLW-computed resonance energies (ARE). ECRE data on the five-membered rings (derived from comparisons with acyclic models) correlate well with nucleus-independent chemical shift (NICS) and other quantitative aromaticity criteria. The ARE of cyclobutadiene is almost the same as butadiene but is 10.5 kcal

  4. Förster Resonance Energy Transfer and Harvesting in II-VI Fractional Monolayer Structures

    Science.gov (United States)

    Shubina, T. V.; Semina, M. A.; Belyaev, K. G.; Rodina, A. V.; Toropov, A. A.; Ivanov, S. V.

    2017-07-01

    We report on Förster resonance energy transfer in the dense arrays of epitaxial quantum dots (QDs), formed by fractional monolayer CdSe insertions within a ZnSe matrix. In such arrays comprising the QDs of different sizes, the energy transfer can take place between the ground levels of small QDs and the excited levels of large radiating QDs, when these states are in resonance. This mechanism provides directional excitation of a limited number of the large QDs possessing the excited levels. It reveals itself by the shrinkage of photoluminescence (PL) bands and the appearance of the narrow single excitonic lines in micro-PL spectra. The strong shortening of characteristic PL decay times in the energy-donating QDs is observed when the distance between them and the energy-accepting QDs decreases. Photoluminescence excitation spectroscopy demonstrates the switching of the dominant energy transfer mechanism at the energy predicted by theoretical modeling of the excitonic levels in the QD arrays. Our results pave the way for engineering of the architecture of excitonic levels in the QD arrays to realize efficient nano-emitters.

  5. Multi-resonant wideband energy harvester based on a folded asymmetric M-shaped cantilever

    Directory of Open Access Journals (Sweden)

    Meng Wu

    2015-07-01

    Full Text Available This article reports a compact wideband piezoelectric vibration energy harvester consisting of three proof masses and an asymmetric M-shaped cantilever. The M-shaped beam comprises a main beam and two folded and dimension varied auxiliary beams interconnected through the proof mass at the end of the main cantilever. Such an arrangement constitutes a three degree-of-freedom vibrating body, which can tune the resonant frequencies of its first three orders close enough to obtain a utility wide bandwidth. The finite element simulation results and the experimental results are well matched. The operation bandwidth comprises three adjacent voltage peaks on account of the frequency interval shortening mechanism. The result shows that the proposed piezoelectric energy harvester could be efficient and adaptive in practical vibration circumstance based on multiple resonant modes.

  6. Foerster resonance energy transfer in inhomogeneous non-dispersive nanophotonic environments

    DEFF Research Database (Denmark)

    Wubs, Martijn; Vos, Willem L.

    A nondispersive inhomogeneous dielectric environment of a donor-acceptor pair of quantum emitters affects their Foerster resonance energy transfer (FRET) rate. We find that this rate does not depend on the emission frequency and hence not on the local optical density of states (LDOS) at that freq......A nondispersive inhomogeneous dielectric environment of a donor-acceptor pair of quantum emitters affects their Foerster resonance energy transfer (FRET) rate. We find that this rate does not depend on the emission frequency and hence not on the local optical density of states (LDOS......) at that frequency, but that it can be expressed as a broad frequency integral over the optical LDOS. Our numerical results illustrate that even with the broadband LDOS it is hard to control the FRET rate....

  7. Multi-resonant wideband energy harvester based on a folded asymmetric M-shaped cantilever

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Meng; Mao, Haiyang; Li, Zhigang; Liu, Ruiwen; Ming, Anjie [Key laboratory of Microelectronics Devices & Integrated Technology, Institute of Microelectronics, Chinese Academic of Sciences, Beijing 100029 (China); Ou, Yi; Ou, Wen [Key laboratory of Microelectronics Devices & Integrated Technology, Institute of Microelectronics, Chinese Academic of Sciences, Beijing 100029 (China); Smart Sensor Engineering Center, Jiangsu R& D Center for Internet of Things, Wuxi 214315 (China)

    2015-07-15

    This article reports a compact wideband piezoelectric vibration energy harvester consisting of three proof masses and an asymmetric M-shaped cantilever. The M-shaped beam comprises a main beam and two folded and dimension varied auxiliary beams interconnected through the proof mass at the end of the main cantilever. Such an arrangement constitutes a three degree-of-freedom vibrating body, which can tune the resonant frequencies of its first three orders close enough to obtain a utility wide bandwidth. The finite element simulation results and the experimental results are well matched. The operation bandwidth comprises three adjacent voltage peaks on account of the frequency interval shortening mechanism. The result shows that the proposed piezoelectric energy harvester could be efficient and adaptive in practical vibration circumstance based on multiple resonant modes.

  8. Non-resonant electromechanical energy harvesting using inter-ferroelectric phase transitions

    Energy Technology Data Exchange (ETDEWEB)

    Pérez Moyet, Richard; Rossetti, George A., E-mail: george.rossetti-jr@uconn.edu [Department of Materials Science and Engineering and Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269 (United States); Stace, Joseph; Amin, Ahmed [Sensors and Sonar Systems Department, Naval Undersea Warfare Center Newport, Newport, Rhode Island 02841 (United States); Finkel, Peter [Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375 (United States)

    2015-10-26

    Non-resonant electromechanical energy harvesting is demonstrated under low frequency excitation (<50 Hz) using [110]{sub C}-poled lead indium niobate-lead magnesium niobate-lead titanate relaxor ferroelectric single crystals with compositions near the morphotropic phase boundary. The efficiency of power generation at the stress-induced phase transition between domain-engineered rhombohedral and orthorhombic ferroelectric states is as much as four times greater than is obtained in the linear piezoelectric regime under identical measurement conditions but during loading below the coercive stress of the phase change. The phase transition mode of electromechanical transduction holds potential for non-resonant energy harvesting from low-frequency vibrations and does not require mechanical frequency up-conversion.

  9. Nonlinear energy channeling in the two-dimensional, locally resonant, unit-cell model. II. Low energy excitations and unidirectional energy transport.

    Science.gov (United States)

    Vorotnikov, K; Starosvetsky, Y

    2015-07-01

    This paper completes a series of two publications devoted to the analytical investigation of energy channeling phenomena, emerging in a locally resonant unit-cell model. The system under consideration comprises an outer mass with internal rotator and subject to the 2D nonlinear local potential. In the present study, we focus on the analysis of the regimes of two-dimensional, nonlinear energy transport forming in the special asymptotic limit of low energy excitations. Unlike the previously considered case, this limit can also be characterized by the absence of resonant interactions between the internal rotator and the motion of an outer element. In the considered limit, we report the emergence of all new, highly nonlinear, transient regimes of unidirectional energy channeling. This phenomenon is manifested by partial and complete targeted energy flow from axial to lateral vibrations, controlled by an internal device. Here, we also show that regimes corresponding to the bidirectional energy channeling as well as the spontaneous energy locking reported in the first paper of the series-persist in the low energy limit as well. In this study, we use a regular multi-scale asymptotic procedure and completely unveil the intrinsic mechanisms governing bi- and unidirectional energy channeling. Numerical simulations are found to be in a fairly good agreement with the predictions of analytic model.

  10. Fluorescence resonance energy transfer sensors for quantitative monitoring of pentose and disaccharide accumulation in bacteria

    Directory of Open Access Journals (Sweden)

    Looger Loren L

    2008-06-01

    Full Text Available Abstract Background Engineering microorganisms to improve metabolite flux requires detailed knowledge of the concentrations and flux rates of metabolites and metabolic intermediates in vivo. Fluorescence resonance energy transfer sensors represent a promising technology for measuring metabolite levels and corresponding rate changes in live cells. These sensors have been applied successfully in mammalian and plant cells but potentially could also be used to monitor steady-state levels of metabolites in microorganisms using fluorimetric assays. Sensors for hexose and pentose carbohydrates could help in the development of fermentative microorganisms, for example, for biofuels applications. Arabinose is one of the carbohydrates to be monitored during biofuels production from lignocellulose, while maltose is an important degradation product of starch that is relevant for starch-derived biofuels production. Results An Escherichia coli expression vector compatible with phage λ recombination technology was constructed to facilitate sensor construction and was used to generate a novel fluorescence resonance energy transfer sensor for arabinose. In parallel, a strategy for improving the sensor signal was applied to construct an improved maltose sensor. Both sensors were expressed in the cytosol of E. coli and sugar accumulation was monitored using a simple fluorimetric assay of E. coli cultures in microtiter plates. In the case of both nanosensors, the addition of the respective ligand led to concentration-dependent fluorescence resonance energy transfer responses allowing quantitative analysis of the intracellular sugar levels at given extracellular supply levels as well as accumulation rates. Conclusion The nanosensor destination vector combined with the optimization strategy for sensor responses should help to accelerate the development of metabolite sensors. The new carbohydrate fluorescence resonance energy transfer sensors can be used for in vivo

  11. Dimerization of MT1-MMP during cellular invasion detected by flourescence resonance energy transfer

    OpenAIRE

    Itoh, Yoshifumi; Palmisano, Ralf; Anilkumar, Narayanapanicker; Nagase, Hideaki; Miyawaki, Atsushi; Seiki, Motoharu

    2011-01-01

    Abstract Homo-dimerization of the membrane-bound collagenase MT1-MMP is crucial for its collagenolytic activity. However, it has not been clear if this dimerization is regulated during cellular invasion into 3D collagen matrices. To address this question, we established a fluorescence resonance energy transfer system to detect MT1-MMP dimerization and analysed the process in cells invading through 3D collagen. Our data indicates that dimerization occurrs dynamically and constantly ...

  12. Polymer-Polymer Förster Resonance Energy Transfer Significantly Boosts the Power Conversion Efficiency of Bulk-Heterojunction Solar Cells.

    Science.gov (United States)

    Gupta, Vinay; Bharti, Vishal; Kumar, Mahesh; Chand, Suresh; Heeger, Alan J

    2015-06-24

    Optically resonant donor polymers can exploit a wider range of the solar spectrum effectively without a complicated tandem design in an organic solar cell. Ultrafast Förster resonance energy transfer (FRET) in a polymer-polymer system that significantly improves the power conversion efficiency in bulk heterojunction polymer solar cells from 6.8% to 8.9% is demonstrated, thus paving the way to achieving 15% efficient solar cells. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Energy funneling in a bent chain of Morse oscillators with long-range coupling

    DEFF Research Database (Denmark)

    Larsen, Peter Ulrik Vingaard; Christiansen, Peter Leth; Bang, Ole

    2004-01-01

    A bent chain of coupled Morse oscillators with long-range dispersive interaction is considered. Moving localized excitations may be trapped in the bending region. Thus chain geometry acts like an impurity. An energy funneling effect is observed in the case of random initial conditions....

  14. Energy saving in multi-standard mobile terminals through short-range cooperation

    National Research Council Canada - National Science Library

    Radwan, Ayman; Rodriguez, Jonathan

    2012-01-01

    .... In this article, we use one advantage of the multiple interfaces, namely short-range (SR) communications. Mobile terminals (MTs) use SR cooperative networking to take advantage of the good channel quality of SR links to save energy in multi-standard MTs...

  15. Design of an ultrahigh-energy-resolution and wide-energy-range soft X-ray beamline.

    Science.gov (United States)

    Xue, L; Reininger, R; Wu, Y-Q; Zou, Y; Xu, Z-M; Shi, Y-B; Dong, J; Ding, H; Sun, J-L; Guo, F-Z; Wang, Y; Tai, R-Z

    2014-01-01

    A new ultrahigh-energy-resolution and wide-energy-range soft X-ray beamline has been designed and is under construction at the Shanghai Synchrotron Radiation Facility. The beamline has two branches: one dedicated to angle-resolved photoemission spectroscopy (ARPES) and the other to photoelectron emission microscopy (PEEM). The two branches share the same plane-grating monochromator, which is equipped with four variable-line-spacing gratings and covers the 20-2000 eV energy range. Two elliptically polarized undulators are employed to provide photons with variable polarization, linear in every inclination and circular. The expected energy resolution is approximately 10 meV at 1000 eV with a flux of more than 3 × 10(10) photons s(-1) at the ARPES sample positions. The refocusing of both branches is based on Kirkpatrick-Baez pairs. The expected spot sizes when using a 10 µm exit slit are 15 µm × 5 µm (horizontal × vertical FWHM) at the ARPES station and 10 µm × 5 µm (horizontal × vertical FWHM) at the PEEM station. The use of plane optical elements upstream of the exit slit, a variable-line-spacing grating and a pre-mirror in the monochromator that allows the influence of the thermal deformation to be eliminated are essential for achieving the ultrahigh-energy resolution.

  16. Fluorescence resonance energy transfer imaging of CFP/YFP labeled NDH in cyanobacterium cell

    Energy Technology Data Exchange (ETDEWEB)

    Ji Dongmei [State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100080 (China); Lv Wei [State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100080 (China); Huang Zhengxi [State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100080 (China); Xia Andong [State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100080 (China)]. E-mail: andong@iccas.ac.cn; Xu Min [Shanghai Institute of Plant Physiology, Chinese Academy of Sciences, Shanghai, 200031 (China); Ma Weimin [Shanghai Institute of Plant Physiology, Chinese Academy of Sciences, Shanghai, 200031 (China); Mi Hualing [Shanghai Institute of Plant Physiology, Chinese Academy of Sciences, Shanghai, 200031 (China)]. E-mail: mihl@iris.sipp.ac.cn; Ogawa Teruo [Shanghai Institute of Plant Physiology, Chinese Academy of Sciences, Shanghai, 200031 (China)]. E-mail: ogawater@xd6.so-net.ne.jp

    2007-01-15

    The laser confocal scanning microscopy combined with time-correlated single photon counting imaging technique to obtain fluorescence intensity and fluorescence lifetime images for fluorescence resonance energy transfer measurement is reported. Both the fluorescence lifetime imaging microscopy (FLIM) and intensity images show inhomogeneous cyan fluorescent protein and yellow fluorescent protein (CFP /YFP) expression or inhomogeneous energy transfer between CFP and YFP over whole cell. The results presented in this work show that FLIM could be a potential method to reveal the structure-function behavior of NAD(P)H dehydrogenase complexes in living cell.

  17. On the Concentration Dependence of Metallic Nano-Particles in Enhanced Forster Resonance Energy Transfer

    Science.gov (United States)

    Hoa, N. M.; Nhung, T. H.; Thao, T. T.; Theu, L. T.; Viet, N. A.

    2017-06-01

    The enhanced Forster resonance energy transfer is obtained in recent experiments. One of the most important experimental facts is the observed strong enhancement of donor fluorescence with increasing concentration of metallic nanoparticle acceptors in the first stage. We propose three types of energy transfer mechanisms (Forster FRET, surface SET, and Coulomb CET) and predict simple relations for their dependencies on the concentration of metallic nano-particles. The competition of these mechanisms leads to the transfer intensity dependence on the concentration dependence of metallic nano-particles. Using these assumptions, we expect and argue about the compatibility between the experimental results.

  18. Time resolved resonant photoemission study of energy level alignment at donor/acceptor interfaces

    Science.gov (United States)

    Costantini, R.; Pincelli, T.; Cossaro, A.; Verdini, A.; Goldoni, A.; Cichoň, S.; Caputo, M.; Pedio, M.; Panaccione, G.; Silly, M. G.; Sirotti, F.; Morgante, A.; Dell'Angela, M.

    2017-09-01

    The knowledge of the picosecond dynamics of the energy level alignment between donor and acceptor materials in organic photovoltaic devices under working conditions is a challenge for fundamental material research. We measured by means of time-resolved Resonant X-ray Photoemission Spectroscopy (RPES) the energy level alignment in ZnPc/C60 films. We employed 800 nm femtosecond laser pulses to pump the system simulating sunlight excitation and X-rays from the synchrotron as a probe. We measured changes in the valence bands due to pump induced modifications of the interface dipole. Our measurements prove the feasibility of time-resolved RPES with high repetition rate sources.

  19. Autonomous Vehicles Have a Wide Range of Possible Energy Impacts (Poster)

    Energy Technology Data Exchange (ETDEWEB)

    Brown, A.; Repac, B.; Gonder, J.

    2013-07-01

    This poster presents initial estimates of the net energy impacts of automated vehicles (AVs). Automated vehicle technologies are increasingly recognized as having potential to decrease carbon dioxide emissions and petroleum consumption through mechanisms such as improved efficiency, better routing, lower traffic congestion, and by enabling advanced technologies. However, some effects of AVs could conceivably increase fuel consumption through possible effects such as longer distances traveled, increased use of transportation by underserved groups, and increased travel speeds. The net effect on petroleum use and climate change is still uncertain. To make an aggregate system estimate, we first collect best estimates for the energy impacts of approximately ten effects of AVs. We then use a modified Kaya Identity approach to estimate the range of aggregate effects and avoid double counting. We find that depending on numerous factors, there is a wide range of potential energy impacts. Adoption of automated personal or shared vehicles can lead to significant fuel savings but has potential for backfire.

  20. Darwin: dose monitoring system applicable to various radiations with wide energy ranges.

    Science.gov (United States)

    Sato, T; Satoh, D; Endo, A; Yamaguchi, Y

    2007-01-01

    A new radiation dose monitor, designated as DARWIN (Dose monitoring system Applicable to various Radiations with Wide energy ranges), has been developed for real-time monitoring of doses in workspaces and surrounding environments of high-energy accelerator facilities. DARWIN is composed of a phoswitch-type scintillation detector, which consists of liquid organic scintillator BC501A coupled with ZnS(Ag) scintillation sheets doped with (6)Li, and a data acquisition system based on a Digital-Storage-Oscilloscope. DARWIN has the following features: (1) capable of monitoring doses from neutrons, photons and muons with energies from thermal energy to 1 GeV, 150 keV to 100 MeV and 1 MeV to 100 GeV, respectively, (2) highly sensitive with precision and (3) easy to operate with a simple graphical user-interface. The performance of DARWIN was examined experimentally in several radiation fields. The results of the experiments indicated the accuracy and wide response range of DARWIN for measuring dose rates from neutrons, photons and muons with wide energies. It was also found from the experiments that DARWIN enables us to monitor small fluctuations of neutron dose rates near the background level because of its high sensitivity. With these properties, DARWIN will be able to play a very important role for improving radiation safety in high-energy accelerator facilities.

  1. Energy distribution and local fluctuations in strongly coupled open quantum systems: The extended resonant level model

    Science.gov (United States)

    Ochoa, Maicol A.; Bruch, Anton; Nitzan, Abraham

    2016-07-01

    We study the energy distribution in the extended resonant level model at equilibrium. Previous investigations [Phys. Rev. B 89, 161306 (2014), 10.1103/PhysRevB.89.161306; Phys. Rev. B 93, 115318 (2016), 10.1103/PhysRevB.93.115318] have found, for a resonant electronic level interacting with a thermal free-electron wide-band bath, that the expectation value for the energy of the interacting subsystem can be correctly calculated by considering a symmetric splitting of the interaction Hamiltonian between the subsystem and the bath. However, the general implications of this approach were questioned [Phys. Rev. B 92, 235440 (2015), 10.1103/PhysRevB.92.235440]. Here, we show that, already at equilibrium, such splitting fails to describe the energy fluctuations, as measured here by the second and third central moments (namely, width and skewness) of the energy distribution. Furthermore, we find that when the wide-band approximation does not hold, no splitting of the system-bath interaction can describe the system thermodynamics. We conclude that in general no proper division subsystem of the Hamiltonian of the composite system can account for the energy distribution of the subsystem. This also implies that the thermodynamic effects due to local changes in the subsystem cannot in general be described by such splitting.

  2. Temperature- and frequency-dependent dielectric properties of biological tissues within the temperature and frequency ranges typically used for magnetic resonance imaging-guided focused ultrasound surgery.

    Science.gov (United States)

    Fu, Fanrui; Xin, Sherman Xuegang; Chen, Wufan

    2014-02-01

    This study aimed to obtain the temperature- and frequency-dependent dielectric properties of tissues subjected to magnetic resonance (MR) scanning for MR imaging-guided focused ultrasound surgery (MRgFUS). These variables are necessary to calculate radio frequency electromagnetic fields distribution and specific radio frequency energy absorption rate (SAR) in the healthy tissues surrounding the target tumours, and their variation may affect the efficacy of advanced RF pulses. The dielectric properties of porcine uterus, liver, kidney, urinary bladder, skeletal muscle, and fat were determined using an open-ended coaxial probe method. The temperature range was set from 36 °C to 60 °C; and the frequencies were set at 42.58 (1 T), 64 (1.5 T), 128 (3 T), 170 (4 T), 298 (7 T), 400 (9 T), and 468 MHz (11 T). Within the temperature and frequency ranges, the dielectric constants were listed as follows: uterus 49.6-121.64, liver 44.81-127.68, kidney 37.3-169.26, bladder 42.43-125.95, muscle 58.62-171.7, and fat 9.2327-20.2295. The following conductivities were obtained at the same temperature and frequency ranges: uterus 0.5506-1.4419, liver 0.5174-0.9709, kidney 0.8061-1.3625, bladder 0.6766-1.1817, muscle 0.8983-1.3083, and fat 0.1552-0.2316. The obtained data are consistent with the temperature and frequency ranges typically used in MRgFUS and thus can be used as reference to calculate radio frequency electromagnetic fields and SAR distribution inside the healthy tissues subjected to MR scanning for MRgFUS.

  3. Energy saving mechanisms, collective behavior and the variation range hypothesis in biological systems: A review.

    Science.gov (United States)

    Trenchard, Hugh; Perc, Matjaž

    2016-09-01

    Energy saving mechanisms are ubiquitous in nature. Aerodynamic and hydrodynamic drafting, vortice uplift, Bernoulli suction, thermoregulatory coupling, path following, physical hooks, synchronization, and cooperation are only some of the better-known examples. While drafting mechanisms also appear in non-biological systems such as sedimentation and particle vortices, the broad spectrum of these mechanisms appears more diversely in biological systems that include bacteria, spermatozoa, various aquatic species, birds, land animals, semi-fluid dwellers like turtle hatchlings, as well as human systems. We present the thermodynamic framework for energy saving mechanisms, and we review evidence in favor of the variation range hypothesis. This hypothesis posits that, as an evolutionary process, the variation range between strongest and weakest group members converges on the equivalent energy saving quantity that is generated by the energy saving mechanism. We also review self-organized structures that emerge due to energy saving mechanisms, including convective processes that can be observed in many systems over both short and long time scales, as well as high collective output processes in which a form of collective position locking occurs. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  4. Short-range second order screened exchange correction to RPA correlation energies

    Science.gov (United States)

    Beuerle, Matthias; Ochsenfeld, Christian

    2017-11-01

    Direct random phase approximation (RPA) correlation energies have become increasingly popular as a post-Kohn-Sham correction, due to significant improvements over DFT calculations for properties such as long-range dispersion effects, which are problematic in conventional density functional theory. On the other hand, RPA still has various weaknesses, such as unsatisfactory results for non-isogyric processes. This can in parts be attributed to the self-correlation present in RPA correlation energies, leading to significant self-interaction errors. Therefore a variety of schemes have been devised to include exchange in the calculation of RPA correlation energies in order to correct this shortcoming. One of the most popular RPA plus exchange schemes is the second order screened exchange (SOSEX) correction. RPA + SOSEX delivers more accurate absolute correlation energies and also improves upon RPA for non-isogyric processes. On the other hand, RPA + SOSEX barrier heights are worse than those obtained from plain RPA calculations. To combine the benefits of RPA correlation energies and the SOSEX correction, we introduce a short-range RPA + SOSEX correction. Proof of concept calculations and benchmarks showing the advantages of our method are presented.

  5. Direct measurement of low-energy $^{22}$Ne(p,$\\gamma$)$^{23}$Na resonances

    CERN Document Server

    Depalo, R; Aliotta, M; Anders, M; Bemmerer, D; Best, A; Boeltzig, A; Broggini, C; Bruno, C G; Caciolli, A; Ciani, G F; Corvisiero, P; Davinson, T; Di Leva, A; Elekes, Z; Ferraro, F; Formicola, A; Fülöp, Zs; Gervino, G; Guglielmetti, A; Gustavino, C; Gyürky, Gy; Imbriani, G; Junker, M; Menegazzo, R; Mossa, V; Pantaleo, F R; Piatti, D; Prati, P; Straniero, O; Szücs, T; Takács, M P; Trezzi, D

    2016-01-01

    The $^{22}$Ne(p,$\\gamma$)$^{23}$Na reaction is the most uncertain process in the neon-sodium cycle of hydrogen burning. At temperatures relevant for nucleosynthesis in asymptotic giant branch stars and classical novae, its uncertainty is mainly due to a large number of predicted but hitherto unobserved resonances at low energy. Purpose: A new direct study of low energy $^{22}$Ne(p,$\\gamma$)$^{23}$Na resonances has been performed at the Laboratory for Underground Nuclear Astrophysics (LUNA), in the Gran Sasso National Laboratory, Italy. Method: The proton capture on $^{22}$Ne was investigated in direct kinematics, delivering an intense proton beam to a $^{22}$Ne gas target. $\\gamma$ rays were detected with two high-purity germanium detectors enclosed in a copper and lead shielding suppressing environmental radioactivity. Results: Three resonances at 156.2 keV ($\\omega\\gamma$ = (1.48\\,$\\pm$\\,0.10)\\,$\\cdot$\\,10$^{-7}$ eV), 189.5 keV ($\\omega\\gamma$ = (1.87\\,$\\pm$\\,0.06)\\,$\\cdot$\\,10$^{-6}$ eV) and 259.7 keV ($\\o...

  6. Synthesis and systematic evaluation of dark resonance energy transfer (DRET)-based library and its application in cell imaging.

    Science.gov (United States)

    Su, Dongdong; Teoh, Chai Lean; Kang, Nam-Young; Yu, Xiaotong; Sahu, Srikanta; Chang, Young-Tae

    2015-03-01

    In this paper, we report a new strategy for constructing a dye library with large Stokes shifts. By coupling a dark donor with BODIPY acceptors of tunable high quantum yield, a novel dark resonance energy transfer (DRET)-based library, named BNM, has been synthesized. Upon excitation of the dark donor (BDN) at 490 nm, the absorbed energy is transferred to the acceptor (BDM) with high efficiency, which was tunable in a broad range from 557 nm to 716 nm, with a high quantum yield of up to 0.8. It is noteworthy to mention that the majority of the non-radiative energy loss of the donor was converted into the acceptor's fluorescence output with a minimum leak of donor emission. Fluorescence imaging tested in live cells showed that the BNM compounds are cell-permeable and can also be employed for live-cell imaging. This is a new library which can be excited through a dark donor allowing for strong fluorescence emission in a wide range of wavelengths. Thus, the BNM library is well suited for high-throughput screening or multiplex experiments in biological applications by using a single laser excitation source. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Resonances in low-energy electron elastic scattering from Fullerenes C60 through C92

    Science.gov (United States)

    Felfli, Zineb; Msezane, Alfred

    2017-04-01

    The electron affinity (EA) provides a stringent test of theory when the calculated and measured EAs are compared. A strong motivation for the fundamental investigations of low-energy electron elastic scattering from the selected fullerenes C60, C70, C74, C80, C82, C84 and C92 is the availability of high quality measured EAs. The Regge pole calculated electron elastic total cross sections for these fullerenes are found to be characterized generally by Ramsauer-Townsend (R-T) minima, shape resonances and dramatically sharp resonances manifesting stable negative ion formation. The extracted binding energies for the resultant anions agree excellently with the measured EAs of the fullerenes listed above, giving great credence to the Regge pole method and confirming that fullerenes behave like ``big atoms''. Common among all these fullerenes is the appearance of their ground state negative ions at their second R-T minima, similarly to the atomic Au case. This work was supported by U.S. DOE, Basic Energy Sciences, Office of Energy Research.

  8. Non-resonant electromagnetic energy harvester for car-key applications

    Science.gov (United States)

    Li, X.; Hehn, T.; Thewes, M.; Kuehne, I.; Frey, A.; Scholl, G.; Manoli, Y.

    2013-12-01

    This paper presents a novel non-resonant electromagnetic energy harvester for application in a remote car-key, to extend the lifetime of the battery or even to realize a fully energy autonomous, maintenance-free car-key product. Characteristic for a car-key are low frequency and large amplitude motions during normal daily operation. The basic idea of this non-resonant generator is to use a round flat permanent magnet moving freely in a round flat cavity, which is packaged on both sides by printed circuit boards embedded with multi-layer copper coils. The primary goal of this structure is to easily integrate the energy harvester with the existing electrical circuit module into available commercial car-key designs. The whole size of the energy harvester is comparable to a CR2032 coin battery. To find out the best power-efficient and optimal design, several magnets with different dimensions and magnetizations, and various layouts of copper coils were analysed and built up for prototype testing. Experimental results show that with an axially magnetized NdFeB magnet and copper coils of design variant B a maximum open circuit voltage of 1.1V can be observed.

  9. Nanophotonic Control of the Förster Resonance Energy Transfer Efficiency

    DEFF Research Database (Denmark)

    Blum, Christian; Zijlstra, Niels; Lagendijk, Ad

    2012-01-01

    We have studied the influence of the local density of optical states (LDOS) on the rate and efficiency of Forster resonance energy transfer (FRET) from a donor to an acceptor. The donors and acceptors are dye molecules that are separated by a short strand of double-stranded DNA. The LDOS is contr......We have studied the influence of the local density of optical states (LDOS) on the rate and efficiency of Forster resonance energy transfer (FRET) from a donor to an acceptor. The donors and acceptors are dye molecules that are separated by a short strand of double-stranded DNA. The LDOS...... is controlled by carefully positioning the FRET pairs near a mirror. We find that the energy transfer efficiency changes with LDOS, and that, in agreement with theory, the energy transfer rate is independent of the LDOS, which allows one to quantitatively control FRET systems in a new way. Our results imply...... a change in the characteristic Forster distance, in contrast to common lore that this distance is fixed for a given FRET pair....

  10. NATO Advanced Study Institute on Magnetic Resonance : Introduction, Advanced Topics and Applications to Fossil Energy

    CERN Document Server

    Fraissard, Jacques

    1984-01-01

    This volume contains the lectures presented at an Advanced Study Institute on "Magnetic Resonance Techniques in Fossil Energy Problems," which was held at the village of Maleme, Crete, in July of 1983. As of this writing, a different popular attitude prevails from that when the ASI was proposed as far as how critical the world energy picture is. In the popular press, a panglossian attitude (the "petroleum glut" of the 80's) has replaced the jeremiads of the 70's ( a catastrophic "energy crisis"). Yet, there are certain important constants: (a) for the foreseeable future, fossil energy sources (petroleum, coal, oil shale, etc. ) will continue to be of paramount importance; and (b) science and technology of the highest order are needed to extend the fossil ener~y resource base and to utilize it in a cost-effective manner that is also environmentally acceptable. It is precisely this second item that this volume addresses. The volume introduces the phenomenology of magnetic resonance ~n a unified and detailed man...

  11. Pulsed ion hall accelerator for investigation of reactions between light nuclei in the astrophysical energy range

    Science.gov (United States)

    Bystritsky, V. M.; Bystritsky, Vit. M.; Dudkin, G. N.; Nechaev, B. A.; Padalko, V. N.

    2017-07-01

    The factors defining the constraints on the current characteristics of the magnetically insulated ion diode (IDM) are considered. The specific current parameters close to the maximum possible ones are obtained for the particular IDM-40 design assigned for acceleration of light ions and investigation of nuclear reactions with small cross sections in the astrophysical energy range (2-40 keV) in the entrance channel. It is experimentally demonstrated that the chosen optimal operation conditions for IDM-40 units provide high stability of the parameters (energy distribution and composition of accelerated particle beams, degree of neutralization) of the accelerated particle flux, which increases during the working pulse.

  12. Fluorescence Resonance Energy Transfer in Living Cells Reveals Dynamic Membrane Changes in the Initiation of B Cell Signaling

    National Research Council Canada - National Science Library

    Hea Won Sohn; Pavel Tolar; Tian Jin; Susan K. Pierce

    2006-01-01

    .... Here we use fluorescence resonance energy transfer (FRET) in living cells to detect the interaction of the BCR with a Lyn-based membrane-targeted reporter in the first several seconds after BCR clustering...

  13. Experimental observation of electron bounce resonance through electron energy distribution measurement in a finite size inductively coupled plasma

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Seuli [Department of Nanoscale Semiconductor Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763 (Korea, Republic of); Kang, Hyun-Ju; Kim, Yu-Sin; Chang, Yoon-Min; Chung, Chin-Wook, E-mail: joykang@hanyang.ac.kr [Department of Electrical Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763 (Korea, Republic of); Kwon, Deuk-Chul [Plasma Technology Research Center, National Fusion Research Institute, 169-148 Gwahak-ro, Yuseong-gu, Daejeon 34133 (Korea, Republic of)

    2016-06-15

    The electron bounce resonance was experimentally investigated in a low pressure planar inductively coupled plasma. The electron energy probability functions (EEPFs) were measured at different chamber heights and the energy diffusion coefficients were calculated by the kinetic model. It is found that the EEPFs begin to flatten at the first electron bounce resonance condition, and the plateau shifts to a higher electron energy as the chamber height increases. The plateau which indicates strong electron heating corresponds not only to the electron bounce resonance condition but also to the peaks of the first component of the energy diffusion coefficients. As a result, the plateau formation in the EEPFs is mainly due to the electron bounce resonance in a finite inductive discharge.

  14. On the dispersion management of fluorite whispering-gallery mode resonators for Kerr optical frequency comb generation in the telecom and mid-infrared range.

    Science.gov (United States)

    Lin, Guoping; Chembo, Yanne K

    2015-01-26

    Optical whispering gallery mode (WGM) resonators have been very attracting platforms for versatile Kerr frequency comb generations. We report a systematic study on the material dispersion of various optical materials that are capable of supporting quality factors above 109. Using an analytical approximation of WGM resonant frequencies in disk resonators, we investigate the effect of the geometry and transverse mode order on the total group-velocity dispersion (GVD). We demonstrate that the major radii and the radial mode indices play an important role in tailoring the GVD of WGM resonators. In particular, our study shows that in WGM disk-resonators, the polar families of modes have very similar GVD, while the radial families of modes feature dispersion values that can differ by up to several orders of magnitude. The effect of these giant dispersion shifts are experimentally evidenced in Kerr comb generation with magnesium fluoride. From a more general perspective, this critical feature enables to push the zero-dispersion wavelength of fluorite crystals towards the mid-infrared (mid-IR) range, thereby allowing for efficient Kerr comb generation in that spectral range. We show that barium fluoride is the most interesting crystal in this regard, due to its zero dispersion wavelength (ZDW) at 1.93 μm and an optimal dispersion profile in the mid-IR regime. We expect our results to facilitate the design of different platforms for Kerr frequency comb generations in both telecommunication and mid-IR spectral ranges.

  15. 3He(α, γ7Be cross section in a wide energy range

    Directory of Open Access Journals (Sweden)

    Szücs Tamás

    2017-01-01

    Full Text Available The reaction rate of the 3He(α,γ7 Be reaction is important both in the Big Bang Nucleosynthesis (BBN and in the Solar hydrogen burning. There have been a lot of experimental and theoretical efforts to determine this reaction rate with high precision. Some long standing issues have been solved by the more precise investigations, like the different S(0 values predicted by the activation and in-beam measurement. However, the recent, more detailed astrophysical model predictions require the reaction rate with even higher precision to unravel new issues like the Solar composition. One way to increase the precision is to provide a comprehensive dataset in a wide energy range, extending the experimental cross section database of this reaction. This paper presents a new cross section measurement between Ecm = 2.5 − 4.4 MeV, in an energy range which extends above the 7Be proton separation threshold.

  16. Distortion-triggered loss of long-range order in solids with bonding energy hierarchy.

    Science.gov (United States)

    Kolobov, A V; Krbal, M; Fons, P; Tominaga, J; Uruga, T

    2011-04-01

    An amorphous-to-crystal transition in phase-change materials like Ge-Sb-Te is widely used for data storage. The basic principle is to take advantage of the property contrast between the crystalline and amorphous states to encode information; amorphization is believed to be caused by melting the materials with an intense laser or electrical pulse and subsequently quenching the melt. Here, we demonstrate that distortions in the crystalline phase may trigger a collapse of long-range order, generating the amorphous phase without going through the liquid state. We further show that the principal change in optical properties occurs during the distortion of the still crystalline structure, upsetting yet another commonly held belief that attributes the change in properties to the loss of long-range order. Furthermore, our results suggest a way to lower energy consumption by condensing phase change inducing energy into shorter pulses or through the use of coherent phonon excitation.

  17. Efficient Exciton Diffusion and Resonance-Energy Transfer in Multi-Layered Organic Epitaxial Nanofibers

    DEFF Research Database (Denmark)

    Tavares, Luciana; Cadelano, Michele; Quochi, Francesco

    2015-01-01

    Multi-layered epitaxial nanofibers are exemplary model systems for the study of exciton dynamics and lasing in organic materials due to their well-defined morphology, high luminescence efficiencies, and color tunability. We resort to temperature-dependent cw and picosecond photoluminescence (PL......) spectroscopy to quantify exciton diffusion and resonance-energy transfer (RET) processes in multi-layered nanofibers consisting of alternating layers of para-hexaphenyl (p6P) and α-sexithiophene (6T), serving as exciton donor and acceptor material, respectively. The high probability for RET processes...... is confirmed by Quantum Chemical calculations. The activation energy for exciton diffusion in p6P is determined to be as low as 19 meV, proving p6P epitaxial layers also as a very suitable donor material system. The small activation energy for exciton diffusion of the p6P donor material, the inferred high p6P...

  18. An Energy-Efficient Link with Adaptive Transmit Power Control for Long Range Networks

    DEFF Research Database (Denmark)

    Blaszczyk, Tomasz; Lynggaard, Per

    2016-01-01

    — A considerable amount of research is carried out to develop a reliable smart sensor system with high energy efficiency for battery operated wireless IoT devices in the agriculture sector. However, only a limited amount of research has covered automatic transmission power adjustment schemes...... and algorithms which are essential for deployment of wireless IoT nodes. This paper presents an adaptive link algorithm for farm applications with emphasis on power adjustment for long range communication networks....

  19. An Energy-Efficient Link with Adaptive Transmit Power Control for Long Range Networks

    DEFF Research Database (Denmark)

    Lynggaard, P.; Blaszczyk, Tomasz

    2016-01-01

    A considerable amount of research is carried out to develop a reliable smart sensor system with high energy efficiency for battery operated wireless IoT devices in the agriculture sector. However, only a limited amount of research has covered automatic transmission power adjustment schemes...... and algorithms which are essential for deployment of wireless IoT nodes. This paper presents an adaptive link algorithm for farm applications with emphasis on power adjustment for long range communication networks....

  20. Exploiting short-range cooperation for energy efficient vertical handover operations

    OpenAIRE

    Foukas, Xenofon; Kontovasilis, K.; Marina, M. K.

    2015-01-01

    The availability of multiple collocated wireless networks using heterogeneous technologies and the multi-access support of contemporary mobile devices have allowed wireless connectivity optimization, enabled through vertical handover (VHO) operations. However, this comes at a high energy consumption on the mobile device, due to the inherently expensive nature of some of the involved operations. This work proposes exploiting short-range cooperation among collocated mobile devices to improve th...

  1. Energy- and time-resolved detection of prompt gamma-rays for proton range verification.

    Science.gov (United States)

    Verburg, Joost M; Riley, Kent; Bortfeld, Thomas; Seco, Joao

    2013-10-21

    In this work, we present experimental results of a novel prompt gamma-ray detector for proton beam range verification. The detection system features an actively shielded cerium-doped lanthanum(III) bromide scintillator, coupled to a digital data acquisition system. The acquisition was synchronized to the cyclotron radio frequency to separate the prompt gamma-ray signals from the later-arriving neutron-induced background. We designed the detector to provide a high energy resolution and an effective reduction of background events, enabling discrete proton-induced prompt gamma lines to be resolved. Measuring discrete prompt gamma lines has several benefits for range verification. As the discrete energies correspond to specific nuclear transitions, the magnitudes of the different gamma lines have unique correlations with the proton energy and can be directly related to nuclear reaction cross sections. The quantification of discrete gamma lines also enables elemental analysis of tissue in the beam path, providing a better prediction of prompt gamma-ray yields. We present the results of experiments in which a water phantom was irradiated with proton pencil-beams in a clinical proton therapy gantry. A slit collimator was used to collimate the prompt gamma-rays, and measurements were performed at 27 positions along the path of proton beams with ranges of 9, 16 and 23 g cm(-2) in water. The magnitudes of discrete gamma lines at 4.44, 5.2 and 6.13 MeV were quantified. The prompt gamma lines were found to be clearly resolved in dimensions of energy and time, and had a reproducible correlation with the proton depth-dose curve. We conclude that the measurement of discrete prompt gamma-rays for in vivo range verification of clinical proton beams is feasible, and plan to further study methods and detector designs for clinical use.

  2. Physics of reflective optics for the soft gamma-ray photon energy range.

    Science.gov (United States)

    Fernández-Perea, Mónica; Descalle, Marie-Anne; Soufli, Regina; Ziock, Klaus P; Alameda, Jennifer; Baker, Sherry L; McCarville, Tom J; Honkimäki, Veijo; Ziegler, Eric; Jakobsen, Anders C; Christensen, Finn E; Pivovaroff, Michael J

    2013-07-12

    Traditional multilayer reflective optics that have been used in the past for imaging at x-ray photon energies as high as 200 keV are governed by classical wave phenomena. However, their behavior at higher energies is unknown, because of the increasing effect of incoherent scattering and the disagreement between experimental and theoretical optical properties of materials in the hard x-ray and gamma-ray regimes. Here, we demonstrate that multilayer reflective optics can operate efficiently and according to classical wave physics up to photon energies of at least 384 keV. We also use particle transport simulations to quantitatively determine that incoherent scattering takes place in the mirrors but it does not affect the performance at the Bragg angles of operation. Our results open up new possibilities of reflective optical designs in a spectral range where only diffractive optics (crystals and lenses) and crystal monochromators have been available until now.

  3. Photodissociation of HCN and HNC isomers in the 7-10 eV energy range

    Energy Technology Data Exchange (ETDEWEB)

    Chenel, Aurelie; Roncero, Octavio, E-mail: octavio.roncero@csic.es [Instituto de Física Fundamental (IFF-CSIC), C.S.I.C., Serrano 123, 28006 Madrid (Spain); Aguado, Alfredo [Departamento de Química Física Aplicada (UAM), Unidad Asociada a IFF-CSIC, Facultad de Ciencias Módulo 14, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Agúndez, Marcelino; Cernicharo, José [Instituto de Ciencia de Materiales de Madrid, CSIC, C/ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco (Spain)

    2016-04-14

    The ultraviolet photoabsorption spectra of the HCN and HNC isomers have been simulated in the 7-10 eV photon energy range. For this purpose, the three-dimensional adiabatic potential energy surfaces of the 7 lowest electronic states, and the corresponding transition dipole moments, have been calculated, at multireference configuration interaction level. The spectra are calculated with a quantum wave packet method on these adiabatic potential energy surfaces. The spectra for the 3 lower excited states, the dissociative electronic states, correspond essentially to predissociation peaks, most of them through tunneling on the same adiabatic state. The 3 higher electronic states are bound, hereafter electronic bound states, and their spectra consist of delta lines, in the adiabatic approximation. The radiative lifetime towards the ground electronic states of these bound states has been calculated, being longer than 10 ns in all cases, much longer that the characteristic predissociation lifetimes. The spectra of HCN is compared with the available experimental and previous theoretical simulations, while in the case of HNC there are no previous studies to our knowledge. The spectrum for HNC is considerably more intense than that of HCN in the 7-10 eV photon energy range, which points to a higher photodissociation rate for HNC, compared to HCN, in astrophysical environments illuminated by ultraviolet radiation.

  4. A genetically encoded Förster resonance energy transfer sensor for monitoring in vivo trehalose-6-phosphate dynamics.

    Science.gov (United States)

    Peroza, Estevão A; Ewald, Jennifer C; Parakkal, Geetha; Skotheim, Jan M; Zamboni, Nicola

    2015-04-01

    Trehalose-6-phosphate is a pivotal regulator of sugar metabolism, growth, and osmotic equilibrium in bacteria, yeasts, and plants. To directly visualize the intracellular levels of intracellular trehalose-6-phosphate, we developed a series of specific Förster resonance energy transfer (FRET) sensors for in vivo microscopy. We demonstrated real-time monitoring of regulation in the trehalose pathway of Escherichia coli. In Saccharomyces cerevisiae, we could show that the concentration of free trehalose-6-phosphate during growth on glucose is in a range sufficient for inhibition of hexokinase. These findings support the hypothesis of trehalose-6-phosphate as the effector of a negative feedback system, similar to the inhibition of hexokinase by glucose-6-phosphate in mammalian cells and controlling glycolytic flux. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. A new biosensor for glucose determination in serum based on up-converting fluorescence resonance energy transfer.

    Science.gov (United States)

    Peng, Jianhong; Wang, Yuhui; Wang, Jialan; Zhou, Xin; Liu, Zhihong

    2011-10-15

    In this work, a new glucose sensor based on up-converting fluorescence resonance energy transfer (UC-FRET) was developed. Up-converting phosphors (UCPs, NaYF(4): Yb, Er), which were covalently labeled with Concanavalin A (ConA), were used as the energy donor with thiolated β-cyclodextrins (SH-β-CDs) functionalized gold nanoparticles as the energy acceptor. Due to the combination between ConA and SH-β-CDs, the energy donor and the acceptor were brought to close proximity, resulting in the quenching of the fluorescence of UCPs by gold nanoparticles. In the presence of glucose which competed with SH-β-CDs towards the binding sites of ConA, the biosensor (UCPs-ConA-SH-β-CDs-Au) was decomposed and the energy donor was separated from the acceptor. Therefore, the fluorescence of UCPs was restored dependent on the concentration of glucose. The increase of UCPs fluorescence intensity was proportional to glucose concentration within the range from 0.4 μM to 10μM in aqueous buffer, with a limit of detection (LOD) of 0.043 μM. A same linear range of glucose concentration was obtained in a human serum matrix (which was pretreated and thus contained no glucose) with a slightly higher LOD (0.065 μM). The glucose sensor was applied to real human serum samples with the results consistent with that of a classic hexokinase (HK) method, indicating that the UC-FRET biosensor was competent for directly sensing glucose in serum samples without optical interference, which benefited from the near infrared (NIR) excitation nature of UCPs. The results of this work suggested that the UC-FRET technique could be a promising alternative for detecting biomolecules in complex biological sample matrixes for diagnostic purposes. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. Optimal all-optical switching of a microcavity resonance in the telecom range using the electronic Kerr effect

    CERN Document Server

    Yüce, Emre; Claudon, Julien; Gérard, Jean-Michel; Vos, Willem L

    2015-01-01

    We have switched GaAs/AlAs and AlGaAs/AlAs planar microcavities operating in the "original" telecom band by exploiting the instantaneous electronic Kerr effect. We demonstrate that resonance frequency reversibly shifts within a picosecond and the magnitude of the shift is affected by the backbone of the $\\lambda-$layer. We investigate experimentally and theoretically the role of the quality factor in terms of its effect on resonance frequency shift. Our model shows that the magnitude of the resonance frequency shift depends on the pump pulse duration and is maximized when the cavity cavity storage time is matched. Our experiments and our calculations indicate that the resonance frequency shift induced via the electronic Kerr effect can be maximized by judicious tuning of the pump frequency, pump power and pump pulse duration relative to the storage time of the cavity.

  7. DNA base pair resolution measurements using resonance energy transfer efficiency in lanthanide doped nanoparticles.

    Directory of Open Access Journals (Sweden)

    Aleksandra Delplanque

    Full Text Available Lanthanide-doped nanoparticles are of considerable interest for biodetection and bioimaging techniques thanks to their unique chemical and optical properties. As a sensitive luminescence material, they can be used as (bio probes in Förster Resonance Energy Transfer (FRET where trivalent lanthanide ions (La3+ act as energy donors. In this paper we present an efficient method to transfer ultrasmall (ca. 8 nm NaYF4 nanoparticles dispersed in organic solvent to an aqueous solution via oxidation of the oleic acid ligand. Nanoparticles were then functionalized with single strand DNA oligomers (ssDNA by inducing covalent bonds between surface carboxylic groups and a 5' amine modified-ssDNA. Hybridization with the 5' fluorophore (Cy5 modified complementary ssDNA strand demonstrated the specificity of binding and allowed the fine control over the distance between Eu3+ ions doped nanoparticle and the fluorophore by varying the number of the dsDNA base pairs. First, our results confirmed nonradiative resonance energy transfer and demonstrate the dependence of its efficiency on the distance between the donor (Eu3+ and the acceptor (Cy5 with sensitivity at a nanometre scale.

  8. Luminescence resonance energy transfer spectroscopy of ATP-binding cassette proteins.

    Science.gov (United States)

    Zoghbi, Maria E; Altenberg, Guillermo A

    2018-04-01

    The ATP-binding cassette (ABC) superfamily includes regulatory and transport proteins. Most human ABC exporters pump substrates out of cells using energy from ATP hydrolysis. Although major advances have been made toward understanding the molecular mechanism of ABC exporters, there are still many issues unresolved. During the last few years, luminescence resonance energy transfer has been used to detect conformational changes in real time, with atomic resolution, in isolated ABC nucleotide binding domains (NBDs) and full-length ABC exporters. NBDs are particularly interesting because they provide the power stroke for substrate transport. Luminescence resonance energy transfer (LRET) is a spectroscopic technique that can provide dynamic information with atomic-resolution of protein conformational changes under physiological conditions. Using LRET, it has been shown that NBD dimerization, a critical step in ABC proteins catalytic cycle, requires binding of ATP to two nucleotide binding sites. However, hydrolysis at just one of the sites can drive dissociation of the NBD dimer. It was also found that the NBDs of the bacterial ABC exporter MsbA reconstituted in a lipid bilayer membrane and studied at 37°C never separate as much as suggested by crystal structures. This observation stresses the importance of performing structural/functional studies of ABC exporters under physiologic conditions. This article is part of a Special Issue entitled: Beyond the Structure-Function Horizon of Membrane Proteins edited by Ute Hellmich, Rupak Doshi and Benjamin McIlwain. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Resonance oscillations of non-reciprocal long-range van der Waals forces between atoms in electromagnetic fields

    OpenAIRE

    Sherkunov, Yury

    2017-01-01

    We study theoretically the van der Waals interaction between two atoms out of equilibrium with isotropic electromagnetic field. We demonstrate that at large interatomic separations, the van der Waals forces are resonant, spatially oscillating and non-reciprocal due to resonance absorption and emission of virtual photons. We suggest that these forces can be used to manipulate and control centre-of-mass and relative motion of atomic pairs.

  10. Higher Energy Intake Variability as Predisposition to Obesity: Novel Approach Using Interquartile Range.

    Science.gov (United States)

    Forejt, Martin; Brázdová, Zuzana Derflerová; Novák, Jan; Zlámal, Filip; Forbelská, Marie; Bienert, Petr; Mořkovská, Petra; Zavřelová, Miroslava; Pohořalá, Aneta; Jurášková, Miluše; Salah, Nabil; Bienertová-Vašků, Julie

    2017-12-01

    It is known that total energy intake and its distribution during the day influences human anthropometric characteristics. However, possible association between variability in total energy intake and obesity has thus far remained unexamined. This study was designed to establish the influence of energy intake variability of each daily meal on the anthropometric characteristics of obesity. A total of 521 individuals of Czech Caucasian origin aged 16–73 years (390 women and 131 men) were included in the study, 7-day food records were completed by all study subjects and selected anthropometric characteristics were measured. The interquartile range (IQR) of energy intake was assessed individually for each meal of the day (as a marker of energy intake variability) and subsequently correlated with body mass index (BMI), body fat percentage (%BF), waist-hip ratio (WHR), and waist circumference (cW). Four distinct models were created using multiple logistic regression analysis and backward stepwise logistic regression. The most precise results, based on the area under the curve (AUC), were observed in case of the %BF model (AUC=0.895) and cW model (AUC=0.839). According to the %BF model, age (penergy intake of key daily meals may increase the likelihood of obesity development. Based on the obtained results, it is necessary to emphasize the regularity in meals intake for maintaining proper body composition.

  11. Local orientational order in liquids revealed by resonant vibrational energy transfer.

    Science.gov (United States)

    Panman, M R; Shaw, D J; Ensing, B; Woutersen, S

    2014-11-14

    We demonstrate that local orientational ordering in a liquid can be observed in the decay of the vibrational anisotropy caused by resonant transfer of vibrational excitations between its constituent molecules. We show that the functional form of this decay is determined by the (distribution of) angles between the vibrating bonds of the molecules between which energy transfer occurs, and that the initial drop in the decay reflects the average angle between nearest neighbors. We use this effect to observe the difference in local orientational ordering in the two hydrogen-bonded liquids ethanol and N-methylacetamide.

  12. A fluorescence resonance energy transfer-based method for histone methyltransferases

    DEFF Research Database (Denmark)

    Devkota, Kanchan; Lohse, Brian; Nyby Jakobsen, Camilla

    2015-01-01

    A simple dye–quencher fluorescence resonance energy transfer (FRET)-based assay for methyltransferases was developed and used to determine kinetic parameters and inhibitory activity at EHMT1 and EHMT2. Peptides mimicking the truncated histone H3 tail were functionalized in each end with a dye...... and a quencher, respectively. When lysine-9 residues in the peptides were methylated, they were protected from cleavage by endoproteinase–EndoLysC, whereas unmethylated peptides were cleaved, resulting in an increase in fluorescent intensity....

  13. Oven controlled N++ [1 0 0] length-extensional mode silicon resonator with frequency stability of 1 ppm over industrial temperature range

    Science.gov (United States)

    You, Weilong; Pei, Binbin; Sun, Ke; Zhang, Lei; Yang, Heng; Li, Xinxin

    2017-10-01

    This paper presents an oven controlled N++ [1 0 0] length-extensional mode silicon resonator, with a lookup-table based control algorithm. The temperature coefficient of resonant frequency (TCF) of the N++ doped resonator is nonlinear, and there is a turnover temperature point at which the TCF is equal to zero. The resonator is maintained at the turnover point by Joule heating; this temperature is a little higher than the upper limit of the industrial temperature range. It is demonstrated that the control algorithm based on the thermoresistor on the substrate and the lookup table for heating voltage versus chip temperature is sufficiently accurate to achieve a frequency stability of  ±0.5 ppm over the industrial temperature range. Because only two leads are required for electrical heating and piezoresistive sensing, the power required for heating of this resonator can be potentially lower than that of the oscillators with closed-loop oven control algorithm. It is also shown that the phase noise can be suppressed at the turnover temperature because of the very low value of the TCF, which justifies the usage of the heating voltage as the excitation voltage of the Wheatstone half-bridge.

  14. Development of detector for neutron monitor of wide energy range. Joint research

    CERN Document Server

    Kim, E; Nakamura, T; Rasolonjatovo, D R D; Shiomi, T; Tanaka, S; Yamaguchi, Y; Yoshizawa, M

    2002-01-01

    Radiation monitoring of neutrons in high-power proton accelerator facilities is very important for radiation safety management for workers and members of the public. In the present study, a neutron detector that can evaluate dose of neutrons in the energy range from thermal energy to 100MeV was developed using an organic liquid scintillator, a boron-loaded scintillator and a sup 6 Li glass scintillator. First, a method was developed to evaluate neutron doses above several MeV by a spectrum weight function (G-function) which is applied to the organic liquid scintillator, and the validity of the methods was confirmed by dose evaluation in some neutron fields. Second, the G-function was applied to the boron-loaded scintillator which detects thermal neutrons by sup 1 sup 0 B(n, alpha) sup 7 Li reaction, in order to expand the covering neutron energy range. The response function and the G-function of the scintillator were evaluated by experiment and calculation, and the characteristics of dose measurement were ana...

  15. Photoproduction in the Energy Range 70-200 GeV

    CERN Multimedia

    2002-01-01

    This experiment continues the photoproduction studies of WA4 and WA57 up to the higher energies made available by the upgrading of the West Hall. An electron beam of energy 200 GeV is used to produce tagged photons in the range 65-180 GeV; The photon beam is incident on a 60 cm liquid hydrogen target in the Omega Spectrometer. A Ring Image Cherenkov detector provides pion/kaon separation up to 150 GeV/c. The Transition Radiation Detector extends the charged pion identification to the momentum range from about 80 GeV/c upwards. The large lead/liquid scintillator calorimeter built by the WA70 collaboration and the new lead/scintillating fibre det (Plug) are used for the detection of the $\\gamma$ rays produced by the interactions of the primary photons in the hydrogen target. \\\\ \\\\ The aim is to make a survey of photoproduction reactions up to photon energies of 200 GeV. The large aperture of the Omega Spectrometer will particularly enable study of fragmentation of the photon to states of high mass, up to @C 9 G...

  16. NEUTRON-PROTON EFFECTIVE RANGE PARAMETERS AND ZERO-ENERGY SHAPE DEPENDENCE.

    Energy Technology Data Exchange (ETDEWEB)

    HACKENBURG, R.W.

    2005-06-01

    A completely model-independent effective range theory fit to available, unpolarized, np scattering data below 3 MeV determines the zero-energy free proton cross section {sigma}{sub 0} = 20.4287 {+-} 0.0078 b, the singlet apparent effective range r{sub s} = 2.754 {+-} 0.018{sub stat} {+-} 0.056{sub syst} fm, and improves the error slightly on the parahydrogen coherent scattering length, a{sub c} = -3.7406 {+-} 0.0010 fm. The triplet and singlet scattering lengths and the triplet mixed effective range are calculated to be a{sub t} = 5.4114 {+-} 0.0015 fm, a{sub s} = -23.7153 {+-} 0.0043 fm, and {rho}{sub t}(0,-{epsilon}{sub t}) = 1.7468 {+-} 0.0019 fm. The model-independent analysis also determines the zero-energy effective ranges by treating them as separate fit parameters without the constraint from the deuteron binding energy {epsilon}{sub t}. These are determined to be {rho}{sub t}(0,0) = 1.705 {+-} 0.023 fm and {rho}{sub s}(0,0) = 2.665 {+-} 0.056 fm. This determination of {rho}{sub t}(0,0) and {rho}{sub s}(0,0) is most sensitive to the sparse data between about 20 and 600 keV, where the correlation between the determined values of {rho}{sub t}(0,0) and {rho}{sub s}(0,0) is at a minimum. This correlation is responsible for the large systematic error in r{sub s}. More precise data in this range are needed. The present data do not event determine (with confidence) that {rho}{sub t}(0,0) {ne} {rho}{sub t}(0, -{epsilon}{sub t}), referred to here as ''zero-energy shape dependence''. The widely used measurement of {sigma}{sub 0} = 20.491 {+-} 0.014 b from W. Dilg, Phys. Rev. C 11, 103 (1975), is argued to be in error.

  17. An analytical model for a piezoelectric vibration energy harvester with resonance frequency tunability

    Directory of Open Access Journals (Sweden)

    Yun Wang

    2015-06-01

    Full Text Available This article conceptually proposes a new method to tune the resonance frequency of piezoelectric vibration energy harvesters, in which the supporting position of the vibrator can be adjusted for frequency tuning. The corresponding analytical model is established to predict the performances of the harvester based on the principles of energy. First, the equivalent stiffness and mass of the vibrator in bending mode are derived explicitly for the different supporting positions. A simple analysis method is then established for the frequency, output voltage, and output power. Finally, some numerical examples are given to demonstrate the presented method. The results are also compared with those by finite element method and good agreement is observed.

  18. Shared-mode assisted resonant energy transfer in the weak coupling regime.

    Science.gov (United States)

    Hennebicq, E; Beljonne, D; Curutchet, C; Scholes, G D; Silbey, R J

    2009-06-07

    Recent work has suggested that correlations in the environments of chromophores can lead to a change in the dynamics of excitation transfer in both the coherent and incoherent limits. An example of this effect that is relevant to many single molecule experiments occurs in the standard Forster model for resonant energy transfer (RET). The standard formula for the FRET rate breaks down when the electronic excitations on weakly interacting donor and acceptor couple to the same vibrational modes. The transfer rate can then no longer be factored into donor emission and acceptor absorption lineshapes, but must be recast in terms of a renormalized phonon reorganization energy accounting for the magnitude and sign of the excitation-vibration couplings. In this paper, we derive theoretically how the FRET rate depends on the shared mode structure and coupling, examine the simplified case of Gaussian lineshapes and then provide a quantitative calculation for a system of current interest.

  19. Förster Resonance Energy Transfer between Quantum Dot Donors and Quantum Dot Acceptors

    Science.gov (United States)

    Chou, Kenny F.; Dennis, Allison M.

    2015-01-01

    Förster (or fluorescence) resonance energy transfer amongst semiconductor quantum dots (QDs) is reviewed, with particular interest in biosensing applications. The unique optical properties of QDs provide certain advantages and also specific challenges with regards to sensor design, compared to other FRET systems. The brightness and photostability of QDs make them attractive for highly sensitive sensing and long-term, repetitive imaging applications, respectively, but the overlapping donor and acceptor excitation signals that arise when QDs serve as both the donor and acceptor lead to high background signals from direct excitation of the acceptor. The fundamentals of FRET within a nominally homogeneous QD population as well as energy transfer between two distinct colors of QDs are discussed. Examples of successful sensors are highlighted, as is cascading FRET, which can be used for solar harvesting. PMID:26057041

  20. Förster Resonance Energy Transfer between Quantum Dot Donors and Quantum Dot Acceptors

    Directory of Open Access Journals (Sweden)

    Kenny F. Chou

    2015-06-01

    Full Text Available Förster (or fluorescence resonance energy transfer amongst semiconductor quantum dots (QDs is reviewed, with particular interest in biosensing applications. The unique optical properties of QDs provide certain advantages and also specific challenges with regards to sensor design, compared to other FRET systems. The brightness and photostability of QDs make them attractive for highly sensitive sensing and long-term, repetitive imaging applications, respectively, but the overlapping donor and acceptor excitation signals that arise when QDs serve as both the donor and acceptor lead to high background signals from direct excitation of the acceptor. The fundamentals of FRET within a nominally homogeneous QD population as well as energy transfer between two distinct colors of QDs are discussed. Examples of successful sensors are highlighted, as is cascading FRET, which can be used for solar harvesting.

  1. Temperature-dependent resonance energy transfer from semiconductor quantum wells to graphene.

    Science.gov (United States)

    Yu, Young-Jun; Kim, Keun Soo; Nam, Jungtae; Kwon, Se Ra; Byun, Hyeryoung; Lee, Kwanjae; Ryou, Jae-Hyun; Dupuis, Russell D; Kim, Jeomoh; Ahn, Gwanghyun; Ryu, Sunmin; Ryu, Mee-Yi; Kim, Jin Soo

    2015-02-11

    Resonance energy transfer (RET) has been employed for interpreting the energy interaction of graphene combined with semiconductor materials such as nanoparticles and quantum-well (QW) heterostructures. Especially, for the application of graphene as a transparent electrode for semiconductor light emitting diodes, the mechanism of exciton recombination processes such as RET in graphene-semiconductor QW heterojunctions should be understood clearly. Here, we characterized the temperature-dependent RET behaviors in graphene/semiconductor QW heterostructures. We then observed the tuning of the RET efficiency from 5% to 30% in graphene/QW heterostructures with ∼60 nm dipole-dipole coupled distance at temperatures of 300 to 10 K. This survey allows us to identify the roles of localized and free excitons in the RET process from the QWs to graphene as a function of temperature.

  2. Electron cyclotron resonance ion source plasma characterization by energy dispersive x-ray imaging

    Science.gov (United States)

    Rácz, R.; Mascali, D.; Biri, S.; Caliri, C.; Castro, G.; Galatà, A.; Gammino, S.; Neri, L.; Pálinkás, J.; Romano, F. P.; Torrisi, G.

    2017-07-01

    Pinhole and CCD based quasi-optical x-ray imaging technique was applied to investigate the plasma of an electron cyclotron resonance ion source (ECRIS). Spectrally integrated and energy resolved images were taken from an axial perspective. The comparison of integrated images taken of argon plasma highlights the structural changes affected by some ECRIS setting parameters, like strength of the axial magnetic confinement, RF frequency and microwave power. Photon counting analysis gives precise intensity distribution of the x-ray emitted by the argon plasma and by the plasma chamber walls. This advanced technique points out that the spatial positions of the electron losses are strongly determined by the kinetic energy of the electrons themselves to be lost and also shows evidences how strongly the plasma distribution is affected by slight changes in the RF frequency.

  3. Determination of mean ionization potential using magnetic resonance imaging for the reduction of proton beam range uncertainties: theory and application

    Science.gov (United States)

    Sudhyadhom, Atchar

    2017-11-01

    The accurate determination of mean ionization potential (I m) has the potential to reduce range uncertainty based margins and therefore allow for more focal treatments in proton radiotherapy. Many methods have been proposed to reduce uncertainty in I m and stopping power ratios (SPR), each with varying degrees of accuracy and issues. In this work, we present a simple parameterized model to determine I m in human biological tissue, allowing for the computation of patient-specific I m at the voxel level using magnetic resonance imaging (MRI). The model requires the measurement of three parameters by MRI, with only two parameters, mass percent water content and mass percent hydrogen content in organic molecules, required for the special case of soft tissues. The accuracy of this I m determination method was evaluated in available ‘standard’ (ICRU Report #44, (ICRU 1989 Tissue Substitutes in Radiation Dosimetry and Measurement (Bethesda, MD: International Commission on Radiation Units and Measurements))) human tissues. The sensitivity of this I m determination method to in vivo perturbations was also tested by calculating the effect of 10% variations in the experimentally measurable parameters on I m and SPR. For the human tissues modeled in this work, a high level of accuracy with low susceptibility to perturbations in measurement error was achieved in the prediction of I m. Root-mean-square errors in I m were within 0.77% and 1.8% for both soft and bony tissues, and were 0.09% and 0.2% for the SPR of soft and bony tissues, respectively, assuming knowledge of electron density. Proof of principle MR measurements and model-based computations of I m and SPR were taken in phantom for a series of hydrogenous solutions and compared against expected I m and SPR calculations from known elemental composition. MR determined I m and SPR values in a known composition solution were determined to within 5% and 0.52%, respectively. We present a novel model to accurately

  4. Equilateral Triangular Dielectric Resonator Nantenna at Optical Frequencies for Energy Harvesting

    Directory of Open Access Journals (Sweden)

    Waleed Tariq Sethi

    2015-01-01

    Full Text Available The last decade has witnessed a remarkable growth in the telecommunication industry. With the introduction of smart gadgets, the demand for high data rate and bandwidth for wireless applications have increased exponentially at the cost of exponential consumption of energy. The latter is pushing the research and industry communities to devise green communication solutions that require the design of energy saving devices and techniques in one part and ambient energy harvesting techniques in the other part. With the advent of nanocomponents fabrication technology, researchers are now able to tap into the THz frequency regime and fabricate optical low profile antennas at a nanoscale. Optical antennas have proved their potential and are revolutionizing a class of novel optical detectors, interconnectors, sensors, and energy harvesting related fields. Authors in this paper propose an equilateral triangular dielectric resonator nantenna (ETDRNA working at 193.5 THz standard optical frequency. The simulated antenna achieves an impedance bandwidth from 192.3 THz to 197.3 THz with an end-fire directivity of 8.6 dBi, covering the entire standard optical window of C-band. Numerical demonstrations prove the efficiency of the nantenna at the frequencies of interest, making it a viable candidate for future green energy harvesting and high speed optical applications.

  5. Energy calibration issues in nuclear resonant vibrational spectroscopy: observing small spectral shifts and making fast calibrations.

    Science.gov (United States)

    Wang, Hongxin; Yoda, Yoshitaka; Dong, Weibing; Huang, Songping D

    2013-09-01

    The conventional energy calibration for nuclear resonant vibrational spectroscopy (NRVS) is usually long. Meanwhile, taking NRVS samples out of the cryostat increases the chance of sample damage, which makes it impossible to carry out an energy calibration during one NRVS measurement. In this study, by manipulating the 14.4 keV beam through the main measurement chamber without moving out the NRVS sample, two alternative calibration procedures have been proposed and established: (i) an in situ calibration procedure, which measures the main NRVS sample at stage A and the calibration sample at stage B simultaneously, and calibrates the energies for observing extremely small spectral shifts; for example, the 0.3 meV energy shift between the 100%-(57)Fe-enriched [Fe4S4Cl4](=) and 10%-(57)Fe and 90%-(54)Fe labeled [Fe4S4Cl4](=) has been well resolved; (ii) a quick-switching energy calibration procedure, which reduces each calibration time from 3-4 h to about 30 min. Although the quick-switching calibration is not in situ, it is suitable for normal NRVS measurements.

  6. Fluorescent material concentration dependency: Förster resonance energy transfer in quasi-solid state DSSCs

    Science.gov (United States)

    Kim, Dong Woo; Jo, Hyun-Jun; Thogiti, Suresh; Yang, Weon Ki; Cheruku, Rajesh; Kim, Jae Hong

    2017-05-01

    Förster resonance energy transfer (FRET) is critical for wide spectral absorption, an increased dye loading, and photocurrent generation of dye-sensitized solar cells (DSSCs). This process consists of organic fluorescent materials (as an energy donor), and an organic dye (as an energy acceptor on TiO2 surfaces) with quasi-solid electrolyte. The judicious choice of the energy donor and acceptor facilitates a strong spectral overlap between the emission and absorption regions of the fluorescent materials and dye. This FRET process enhances the light-harvesting characteristics of quasi-solid state DSSCs. In this study, DSSCs containing different concentrations (0, 1, and 1.5 wt%) of a fluorescent material (FM) as the energy donor are investigated using FRET. The power conversion efficiency of DSSCs containing FMs in a quasi-solid electrolyte increased by 33% over a pristine cell. The optimized cell fabricated with the quasi-solid state DSSC containing 1.0 wt% FM shows a maximum efficiency of 3.38%, with a short-circuit current density ( J SC ) of 4.32 mA/cm-2, and an open-circuit voltage ( V OC ) of 0.68 V under illumination of simulated solar light (AM 1.5G, 100 mW/cm-2). [Figure not available: see fulltext.

  7. Wide energy range personnel neutron dosemeter and its dose evaluation system

    Energy Technology Data Exchange (ETDEWEB)

    Eisen, Y.; Eliau, A.; Faermann, S.; Karpinovitch, Z.; Ovadia, E.; Rosman, M.; Schlesinger, T.; Shamai, Y.; Tal, A. (Israel Atomic Energy Commission, Yavne. Soreq Nuclear Research Center)

    1982-01-01

    A system composed of a Rem response personnel neutron dosemeter for monitoring dose equivalents in the energy range 1 eV to 14 MeV, an electrochemical etching system for revealing damage sites in solid state track etch detectors, a reader for magnifying the etched pits and a microprocessor for evaluating the dose equivalents and their uncertainties are described. The performance and directional dependence of the dosemeter when exposed to monoenergetic and polyenergetic neutron fields in the epithermal and fast energy regions are discussed. Saturation effects in polycarbonate foils are presented and a comparison is made between the response of polycarbonate and CR-39 foils, used as passive detectors in the dosemeter.

  8. True coincidence summing corrections for an extended energy range HPGe detector

    Energy Technology Data Exchange (ETDEWEB)

    Venegas-Argumedo, Y. [Centro de Investigación en Materiales Avanzados (CIMAV), Miguel de Cervantes 120, Chihuahua, Chih 31109 (Mexico); M.S. Student at CIMAV (Mexico); Montero-Cabrera, M. E., E-mail: elena.montero@cimav.edu.mx [Centro de Investigación en Materiales Avanzados (CIMAV), Miguel de Cervantes 120, Chihuahua, Chih 31109 (Mexico)

    2015-07-23

    True coincidence summing (TCS) effect for natural radioactive families of U-238 and Th-232 represents a problem when an environmental sample with a close source-detector geometry measurement is performed. By using a certified multi-nuclide standard source to calibrate an energy extended range (XtRa) HPGe detector, it is possible to obtain an intensity spectrum slightly affected by the TCS effect with energies from 46 to 1836 keV. In this work, the equations and some other considerations required to calculate the TCS correction factor for isotopes of natural radioactive chains are described. It is projected a validation of the calibration, performed with the IAEA-CU-2006-03 samples (soil and water)

  9. CGC/saturation approach for soft interactions at high energy: long range rapidity correlations

    Energy Technology Data Exchange (ETDEWEB)

    Gotsman, E.; Maor, U. [Tel Aviv University, Department of Particle Physics, School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Science, Tel Aviv (Israel); Levin, E. [Tel Aviv University, Department of Particle Physics, School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Science, Tel Aviv (Israel); Universidad Tecnica Federico Santa Maria and Centro Cientifico- Tecnologico de Valparaiso, Departemento de Fisica, Valparaiso (Chile)

    2015-11-15

    In this paper we continue our program to construct a model for high energy soft interactions that is based on the CGC/saturation approach. The main result of this paper is that we have discovered a mechanism that leads to large long range rapidity correlations and results in large values of the correlation function R(y{sub 1}, y{sub 2}) ≥ 1, which is independent of y{sub 1} and y{sub 2}. Such a behavior of the correlation function provides strong support for the idea that at high energies the system of partons that is produced is not only dense but also has strong attractive forces acting between the partons. (orig.)

  10. Design and development of high bioluminescent resonance energy transfer efficiency hybrid-imaging constructs.

    Science.gov (United States)

    Kumar, Manoj; Kovalski, Letícia; Broyles, David; Hunt, Eric A; Daftarian, Pirouz; Dikici, Emre; Daunert, Sylvia; Deo, Sapna K

    2016-04-01

    Here we describe the design and construction of an imaging construct with high bioluminescent resonance energy transfer (BRET) efficiency that is composed of multiple quantum dots (QDs; λem = 655 nm) self-assembled onto a bioluminescent protein, Renilla luciferase (Rluc). This is facilitated by the streptavidin-biotin interaction, allowing the facile formation of a hybrid-imaging construct (HIC) comprising up to six QDs (acceptor) grafted onto a light-emitting Rluc (donor) core. The resulting assembly of multiple acceptors surrounding a donor permits this construct to exhibit high resonance energy transfer efficiency (∼64.8%). The HIC was characterized using fluorescence excitation anisotropy measurements and high-resolution transmission electron microscopy. To demonstrate the application of our construct, a generation-5 (G5) polyamidoamine dendrimer (PAMAM) nanocarrier was loaded with our HIC for in vitro and in vivo imaging. We envision that this design of multiple acceptors and bioluminescent donor will lead to the development of new BRET-based systems useful in sensing, imaging, and other bioanalytical applications. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Electrostatically driven resonance energy transfer in "cationic" biocompatible indium phosphide quantum dots.

    Science.gov (United States)

    Devatha, Gayathri; Roy, Soumendu; Rao, Anish; Mallick, Abhik; Basu, Sudipta; Pillai, Pramod P

    2017-05-01

    Indium Phosphide Quantum Dots (InP QDs) have emerged as an alternative to toxic metal ion based QDs in nanobiotechnology. The ability to generate cationic surface charge, without compromising stability and biocompatibility, is essential in realizing the full potential of InP QDs in biological applications. We have addressed this challenge by developing a place exchange protocol for the preparation of cationic InP/ZnS QDs. The quaternary ammonium group provides the much required permanent positive charge and stability to InP/ZnS QDs in biofluids. The two important properties of QDs, namely bioimaging and light induced resonance energy transfer, are successfully demonstrated in cationic InP/ZnS QDs. The low cytotoxicity and stable photoluminescence of cationic InP/ZnS QDs inside cells make them ideal candidates as optical probes for cellular imaging. An efficient resonance energy transfer (E ∼ 60%) is observed, under physiological conditions, between the cationic InP/ZnS QD donor and anionic dye acceptor. A large bimolecular quenching constant along with a linear Stern-Volmer plot confirms the formation of a strong ground state complex between the cationic InP/ZnS QDs and the anionic dye. Control experiments prove the role of electrostatic attraction in driving the light induced interactions, which can rightfully form the basis for future nano-bio studies between cationic InP/ZnS QDs and anionic biomolecules.

  12. Resonant-energy-transfer-based biosensor for detection of multivalent proteins

    Science.gov (United States)

    Song, Xuedong; Swanson, Basil I.

    1999-12-01

    We have developed a new fluorescence-based biosensor for sensitive detection of species involved in a multivalent interaction. The biosensor system utilizes specific interactions between proteins and cell surface receptors, which trigger a receptor aggregation process. Distance- dependent fluorescence self-quenching and resonant fluorescence energy transfer mechanisms were coupled with a multivalent interaction to probe the receptor aggregation process, providing a sensitive and specific signal transduction method for such a binding event. The fluorescence change induced by the aggregation process can be monitored by different instrument platforms, e.g. fluorimetry and flow cytometry. In this article, a sensitive detection of pentavalent cholera toxin which recognizes ganglioside GMI has been demonstrated through the resonant energy transfer scheme, which can achieve a double color change simultaneously. A detection sensitivity as high as 10 pM has been achieved within a few minutes (c.a. 5 minutes). The simultaneous double color change (an increase of acceptor fluorescence and a decrease of donor fluorescence intensity) of two similar fluorescent probes provides particularly high detection reliability owing to the fact that they act as each other's internal reference. Any external perturbation such as environmental temperature change causes no significant change in signal generation. Besides the application for biological sensing, the method also provides a useful tool for investigation of kinetics and thermodynamics of a multivalent interaction.

  13. Helicase Stepping Investigated with One-Nucleotide Resolution Fluorescence Resonance Energy Transfer

    Science.gov (United States)

    Lin, Wenxia; Ma, Jianbing; Nong, Daguan; Xu, Chunhua; Zhang, Bo; Li, Jinghua; Jia, Qi; Dou, Shuoxing; Ye, Fangfu; Xi, Xuguang; Lu, Ying; Li, Ming

    2017-09-01

    Single-molecule Förster resonance energy transfer is widely applied to study helicases by detecting distance changes between a pair of dyes anchored to overhangs of a forked DNA. However, it has been lacking single-base pair (1-bp) resolution required for revealing stepping kinetics of helicases. We designed a nanotensioner in which a short DNA is bent to exert force on the overhangs, just as in optical or magnetic tweezers. The strategy improved the resolution of Förster resonance energy transfer to 0.5 bp, high enough to uncover differences in DNA unwinding by yeast Pif1 and E. coli RecQ whose unwinding behaviors cannot be differentiated by currently practiced methods. We found that Pif1 exhibits 1-bp-stepping kinetics, while RecQ breaks 1 bp at a time but sequesters the nascent nucleotides and releases them randomly. The high-resolution data allowed us to propose a three-parameter model to quantitatively interpret the apparently different unwinding behaviors of the two helicases which belong to two superfamilies.

  14. Recent developments in Förster resonance energy transfer (FRET) diagnostics using quantum dots.

    Science.gov (United States)

    Geißler, Daniel; Hildebrandt, Niko

    2016-07-01

    The exceptional photophysical properties and the nanometric dimensions of colloidal semiconductor quantum dots (QD) have strongly attracted the bioanalytical community over the last approximately 20 y. In particular, the integration of QDs in the analysis of biological components and interactions, and the related diagnostics using Förster resonance energy transfer (FRET), have allowed researchers to significantly improve and diversify fluorescence-based biosensing. In this TRENDS article, we review some recent developments in QD-FRET biosensing that have implemented this technology in electronic consumer products, multiplexed analysis, and detection without light excitation for diagnostic applications. In selected examples of smartphone-based imaging, single- and multistep FRET, steady-state and time-resolved spectroscopy, and bio/chemiluminescence detection of QDs used as both FRET donors and acceptors, we highlight the advantages of QD-based FRET biosensing for multiplexed and sensitive diagnostics. Graphical Abstract Quantum dots (QDs) can be applied as donors and/or acceptors for Förster resonance energy transfer- (FRET-) based biosensing for multiplexed and sensitive diagnostics in various assay formats.

  15. Luminescence resonance energy transfer (LRET) aptasensor for ochratoxin A detection using upconversion nanoparticles

    Science.gov (United States)

    Jo, Eun-Jung; Byun, Ju-Young; Mun, Hyoyoung; Kim, Min-Gon

    2017-07-01

    We report an aptasensor for homogeneous ochratoxin A (OTA) detection based on luminescence resonance energy transfer (LRET). This system uses upconversion nanoparticles (UCNPs), such as NaYF4:Yb3+, Er 3+, as the donor. The aptamer includes the optimum-length linker (5-mer-length DNA) and OTA-specific aptamer sequences. Black hole quencher 1 (BHQ1), as the acceptor, was modified at the 3' end of the aptamer sequence. BHQ1 plays as a quencher in LRET aptasensor and shows absorption at 543 nm, which overlaps with well the emission of the UCNPs. When OTA is added, the BHQ1-labeled OTA aptamer was folded due to the formation of the G-quadruplex-OTA complex, which induced the BHQ1 close to the UCNPs. Consequently, resonance energy transfer between UCNPs (donor) and BHQ1 (acceptor) enables quenching of upconversion luminescence signals under laser irradiation of 980 nm. Our results showed that the LRET-based aptasensor allows specific OTA analysis with a limit of detection of 0.03 ng/mL. These results demonstrated that the OTA in diverse foods can be detected specifically and sensitively in a homogeneous manner.

  16. Nonlinear energy channeling in the two-dimensional, locally resonant, unit-cell model. I. High energy pulsations and routes to energy localization.

    Science.gov (United States)

    Vorotnikov, K; Starosvetsky, Y

    2015-07-01

    Present paper is the first one in the series devoted to the analytical investigation of energy channeling phenomena emerging in the locally resonant unit-cell model comprising an outer mass incorporating internal rotator and subject to the 2D, nonlinear local potential. In the current study, we mainly focus on the analysis of the mechanisms of formation and bifurcations of the special type of non-stationary regimes, characterized by the massive, bidirectional energy transport between the axial and the lateral vibrations of the outer element controlled by the internal, rotational device as well as the regimes of the unidirectional energy localization. The devised analytical procedure is based on a singular multi-scale analysis constructed for the special asymptotic limit corresponding to the high energy excitations. The basic question of possible coexistence of various stationary and non-stationary system regimes as well as their local and global bifurcations is addressed via the reduction of the global flow on the slow invariant manifold in the vicinity of the fundamental resonance. Numerical simulations fully confirm the analytical predictions concerning the structure of the response regimes and their bifurcations.

  17. Assessment of range-separated functionals in the presence of implicit solvent: Computation of oxidation energy, reduction energy, and orbital energy

    Science.gov (United States)

    Boruah, Abhijit; Borpuzari, Manash Protim; Kawashima, Yukio; Hirao, Kimihiko; Kar, Rahul

    2017-04-01

    Recently, we have investigated the ionization potential (IP) theorem for some small molecules in the presence of external electric field [M. P. Borpuzari et al., J. Chem. Phys. 144, 164113 (2016)]. In this article, we assess the performance of some density functionals, local density approximation, generalized-gradient approximation (GGA), hybrid, meta-GGA hybrid, and range-separated functionals in the presence of two different solvent dielectrics, water and cyclohexane, in reproducing the vertical oxidation energy, reduction energy, and the frontier orbital energies. We also study the accessibility of different computational solvent models like the polarizable continuum model (PCM) and non-equilibrium PCM (NEPCM) in reproducing the desired properties. In general, the range-separated functionals do not perform well in reproducing orbital energies in the PCM. Range separation with the NEPCM is better. It is found that CAM-B3LYP, M06-2X, and ωB97XD functionals reproduce highest occupied molecular orbital energy in solvents, which may be due to the cancellation of PCM and density functional theory errors. Finally, we have tested the validity of the IP theorem in the solvent environment.

  18. Short-range energy budget simulator of single photon lidar demonstrator

    Science.gov (United States)

    Murtazin, Mark V.; Prochazka, Ivan; Blazej, Josef; Pershin, Sergey M.; Lednev, Vasily N.

    2017-05-01

    The compact single photon lidar demonstrator dedicated for asteroid rendezvous missions has been designed and realized in our laboratory two years ago. The instrument provides crucial data on altitude and terrain profile for altitudes exceeding 5 km with a precision of less than 10 cm fulfilling the Rayleigh criterion. One of the calibration procedure of demonstrator is the positioning of receiver and transmitter optics related to detector and laser and the aligning of transmitter and receiver optical common paths. To improve this particular indoor calibration procedure the new simulator of single photon energy budget during short range operation has been created. The comparison of simulated and experimental data will be presented and discussed.

  19. Förster resonance energy transfer beyond 10 nm: exploiting the triplet state kinetics of organic fluorophores.

    Science.gov (United States)

    Hevekerl, Heike; Spielmann, Thiemo; Chmyrov, Andriy; Widengren, Jerker

    2011-11-17

    Inter- or intramolecular distances of biomolecules can be studied by Förster resonance energy transfer (FRET). For most FRET methods, the observable range of distances is limited to 1-10 nm, and the labeling efficiency has to be controlled carefully to obtain accurate distance determinations, especially for intensity-based methods. In this study, we exploit the triplet state of the acceptor fluorophore as a FRET readout using fluorescence correlation spectroscopy and transient state monitoring. The influence of donor fluorescence leaking into the acceptor channel is minimized by a novel suppression algorithm for spectral bleed-through, thereby tolerating a high excess (up to 100-fold) of donor-only labeled samples. The suppression algorithm and the high sensitivity of the triplet state to small changes in the fluorophore excitation rate make it possible to extend the observable range of FRET efficiencies by up to 50% in the presence of large donor-only populations. Given this increased range of FRET efficiencies, its compatibility with organic fluorophores, and the low requirements on the labeling efficiency and instrumentation, we foresee that this approach will be attractive for in vitro and in vivo FRET-based spectroscopy and imaging.

  20. Determining the short-range spin correlations in the spin-chain Li2CuO2 and CuGeO3 compounds using resonant inelastic x-ray scattering.

    Science.gov (United States)

    Monney, Claude; Bisogni, Valentina; Zhou, Ke-Jin; Kraus, Roberto; Strocov, Vladimir N; Behr, Günter; Málek, Jiři; Kuzian, Roman; Drechsler, Stefan-Ludwig; Johnston, Steve; Revcolevschi, Alexandre; Büchner, Bernd; Rønnow, Henrik M; van den Brink, Jeroen; Geck, Jochen; Schmitt, Thorsten

    2013-02-22

    We report a high-resolution resonant inelastic soft x-ray scattering study of the quantum magnetic spin-chain materials Li(2)CuO(2) and CuGeO(3). By tuning the incoming photon energy to the oxygen K edge, a strong excitation around 3.5 eV energy loss is clearly resolved for both materials. Comparing the experimental data to many-body calculations, we identify this excitation as a Zhang-Rice singlet exciton on neighboring CuO(4) plaquettes. We demonstrate that the strong temperature dependence of the inelastic scattering related to this high-energy exciton enables us to probe short-range spin correlations on the 1 meV scale with outstanding sensitivity.

  1. Electrochemiluminescence detection of TNT by resonance energy transfer through the formation of a TNT-amine complex.

    Science.gov (United States)

    Qi, Wenjing; Xu, Min; Pang, Lei; Liu, Zhongyuan; Zhang, Wei; Majeed, Saadat; Xu, Guobao

    2014-04-14

    2,4,6-Trinitrotoluene (TNT) is a widely used nitroaromatic explosive with significant detrimental effects on the environment and human health. Its detection is of great importance. In this study, both electrochemiluminescence (ECL)-based detection of TNT through the formation of a TNT-amine complex and the detection of TNT through electrochemiluminescence resonance energy transfer (ECRET) are developed for the first time. 3-Aminopropyltriethoxysilane (APTES)-modified [Ru(phen)3](2+) (phen=1,10-phenanthroline)-doped silica nanoparticles (RuSiNPs) with uniform sizes of (73±3) nm were synthesized. TNT can interact with APTES-modified RuSiNPs through charge transfer from electron-rich amines in the RuSiNPs to the electron-deficient aromatic ring of TNT to form a red TNT-amine complex. The absorption spectrum of this complex overlaps with the ECL spectrum of the APTES-modified RuSiNPs/triethylamine system. As a result, ECL signals of the APTES-modified RuSiNPs/triethylamine system are turned off in the presence of TNT owing to resonance energy transfer from electrochemically excited RuSiNPs to the TNT-amine complex. This ECRET method has been successfully applied for the sensitive determination of TNT with a linear range from 1×10(-9) to 1×10(-6) M with a fast response time within 1 min. The limit of detection is 0.3 nM. The method exhibits good selectivity towards 2,4-dinitrotoluene, p-nitrotoluene, nitrobenzene, phenol, p-quinone, 8-hydroxyquinoline, p-phenylenediamine, K3[Fe(CN)6], Fe(3+), NO3(-), NO2(-), Cr(3+), Fe(2+), Pb(2+), SO3(2-), formaldehyde, oxalate, proline, and glycine. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. An approximate analytical solution of the Bethe equation for charged particles in the radiotherapeutic energy range.

    Science.gov (United States)

    Grimes, David Robert; Warren, Daniel R; Partridge, Mike

    2017-08-29

    Charged particles such as protons and carbon ions are an increasingly important tool in radiotherapy. There are however unresolved physics issues impeding optimal implementation, including estimation of dose deposition in non-homogeneous tissue, an essential aspect of treatment optimization. Monte Carlo (MC) methods can be employed to estimate radiation profile, and whilst powerful, these are computationally expensive, limiting practicality. In this work, we start from fundamental physics in the form of the Bethe equation to yield a novel approximate analytical solution for particle range, energy and linear energy transfer (LET). The solution is given in terms of the exponential integral function with relativistic co-ordinate transform, allowing application at radiotherapeutic energy levels (50-350 MeV protons, 100-600 Mev/a.m.u carbon ions). Model results agreed closely for protons and carbon-ions (mean error within ≈1%) of literature values. Agreement was high along particle track, with some discrepancy manifesting at track-end. The model presented has applications within a charged particle radiotherapy optimization framework as a rapid method for dose and LET estimation, capable of accounting for heterogeneity in electron density and ionization potential.

  3. Possibilities for polarized pulsed neutron instrumentation based on the time-of-flight spin-resonance energy filter

    CERN Document Server

    Parizzi, A A; Klose, F

    2002-01-01

    We present a new approach for dynamic energy filtering at spallation neutron sources, based on the original concept of the Drabkin spin-resonance flipper. The setup takes advantage of the neutron magnetic moment, and consists of a wavelength-selective magnetic resonator and a supermirror polarizer/analyzer system. We are proposing refinements (time dependence and revised magnetic field profiles) to the basic concepts of the setup, making it suitable for time-of-flight experiments at spallation neutron sources. We outline here possibilities for using this spin resonator as the core of new neutron instruments. (orig.)

  4. Beyond Förster resonance energy transfer in biological and nanoscale systems.

    Science.gov (United States)

    Beljonne, David; Curutchet, Carles; Scholes, Gregory D; Silbey, Robert J

    2009-05-14

    After photoexcitation, energy absorbed by a molecule can be transferred efficiently over a distance of up to several tens of angstroms to another molecule by the process of resonance energy transfer, RET (also commonly known as electronic energy transfer, EET). Examples of where RET is observed include natural and artificial antennae for the capture and energy conversion of light, amplification of fluorescence-based sensors, optimization of organic light-emitting diodes, and the measurement of structure in biological systems (FRET). Forster theory has proven to be very successful at estimating the rate of RET in many donor-acceptor systems, but it has also been of interest to discover when this theory does not work. By identifying these cases, researchers have been able to obtain, sometimes surprising, insights into excited-state dynamics in complex systems. In this article, we consider various ways that electronic energy transfer is promoted by mechanisms beyond those explicitly considered in Forster RET theory. First, we recount the important situations when the electronic coupling is not accurately calculated by the dipole-dipole approximation. Second, we examine the related problem of how to describe solvent screening when the dipole approximation fails. Third, there are situations where we need to be careful about the separability of electronic coupling and spectral overlap factors. For example, when the donors and/or acceptors are molecular aggregates rather than individual molecules, then RET occurs between molecular exciton states and we must invoke generalized Forster theory (GFT). In even more complicated cases, involving the intermediate regime of electronic energy transfer, we should consider carefully nonequilibrium processes and coherences and how bath modes can be shared. Lastly, we discuss how information is obscured by various forms of energetic disorder in ensemble measurements and we outline how single molecule experiments continue to be

  5. Monopole resonances and Jastrow correlations

    Energy Technology Data Exchange (ETDEWEB)

    Dehesa, J.S.; Guardiola, R. (Granada Univ. (Spain). Dept. de Fisica Nuclear); Polls, A.; Ros, J. (Granada Univ. (Spain). Dept. de Fisica Teorica)

    1982-12-02

    The effect of short range correlations on isoscalar monopole resonances in /sup 4/He, /sup 16/O and /sup 40/Ca is analyzed by using a correlated generator coordinate method. We observe an important increase of the excitation energies of the first resonances with respect to the calculation without src, but small effects on the saturation of the EWSR.

  6. Long range surface plasmon resonance with ultra-high penetration depth for self-referenced sensing and ultra-low detection limit using diverging beam approach

    Energy Technology Data Exchange (ETDEWEB)

    Isaacs, Sivan, E-mail: sivan.isaacs@gmail.com; Abdulhalim, Ibrahim [Department of Electro-Optical Engineering and TheIlse Katz Institute for Nanoscale Science and Technology, Ben Gurion University of the Negev, Beer Sheva 84105 (Israel); NEW CREATE Programme, School of Materials Science and Engineering, 1 CREATE Way, Research Wing, #02-06/08, Singapore 138602 (Singapore)

    2015-05-11

    Using an insulator-metal-insulator structure with dielectric having refractive index (RI) larger than the analyte, long range surface plasmon (SP) resonance exhibiting ultra-high penetration depth is demonstrated for sensing applications of large bioentities at wavelengths in the visible range. Based on the diverging beam approach in Kretschmann-Raether configuration, one of the SP resonances is shown to shift in response to changes in the analyte RI while the other is fixed; thus, it can be used as a built in reference. The combination of the high sensitivity, high penetration depth and self-reference using the diverging beam approach in which a dark line is detected of the high sensitivity, high penetration depth, self-reference, and the diverging beam approach in which a dark line is detected using large number of camera pixels with a smart algorithm for sub-pixel resolution, a sensor with ultra-low detection limit is demonstrated suitable for large bioentities.

  7. Average fast neutron flux in three energy ranges in the Quinta assembly irradiated by two types of beams

    Directory of Open Access Journals (Sweden)

    Strugalska-Gola Elzbieta

    2017-01-01

    Full Text Available This work was performed within the international project “Energy plus Transmutation of Radioactive Wastes” (E&T - RAW for investigations of energy production and transmutation of radioactive waste of the nuclear power industry. 89Y (Yttrium 89 samples were located in the Quinta assembly in order to measure an average high neutron flux density in three different energy ranges using deuteron and proton beams from Dubna accelerators. Our analysis showed that the neutron density flux for the neutron energy range 20.8 - 32.7 MeV is higher than for the neutron energy range 11.5 - 20.8 MeV both for protons with an energy of 0.66 GeV and deuterons with an energy of 2 GeV, while for deuteron beams of 4 and 6 GeV we did not observe this.

  8. The simultaneous measurement of energy and linear polarization of the scattered radiation in resonant inelastic soft x-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Braicovich, L., E-mail: lucio.braicovich@polimi.it; Minola, M.; Dellea, G.; Ghiringhelli, G. [CNR-SPIN and Dipartimento di Fisica, Politecnico di Milano, piazza Leonardo Da Vinci 32, Milano I-20133 (Italy); Le Tacon, M. [Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart (Germany); Moretti Sala, M.; Morawe, C.; Peffen, J.-Ch.; Yakhou, F.; Brookes, N. B. [European Synchrotron Radiation Facility, 71 Avenue des Martyrs, Grenoble F-38043 (France); Supruangnet, R. [Synchrotron Light Research Institute, Nakhon Ratchasima (Thailand)

    2014-11-15

    Resonant Inelastic X-ray Scattering (RIXS) in the soft x-ray range is an element-specific energy-loss spectroscopy used to probe the electronic and magnetic excitations in strongly correlated solids. In the recent years, RIXS has been progressing very quickly in terms of energy resolution and understanding of the experimental results, but the interpretation of spectra could further improve, sometimes decisively, from a full knowledge of the polarization of incident and scattered photons. Here we present the first implementation, in a high resolution soft-RIXS spectrometer used to analyze the scattered radiation, of a device allowing the measurement of the degree of linear polarization. The system, based on a graded W/B{sub 4}C multilayer mirror installed in proximity of the CCD detector, has been installed on the AXES spectrometer at the ESRF (European Synchrotron Radiation Facility); it has been fully characterized and it has been used for a demonstration experiment at the Cu L{sub 3} edge on a high-T{sub c} superconducting cuprate. The loss in efficiency suffered by the spectrometer equipped with this test facility was a factor 17.5. We propose also a more advanced version, suitable for a routine use on the next generation of RIXS spectrometers and with an overall efficiency up to 10%.

  9. A single nucleotide polymorphism melt curve assay employing an intercalating dye probe fluorescence resonance energy transfer for forensic analysis.

    Science.gov (United States)

    Halpern, Micah D; Ballantyne, Jack

    2009-08-01

    The characterization and use of DNA sequence polymorphisms are an important aspect of forensic analysis. A number of approaches are being explored for single nucleotide polymorphism (SNP) genotyping, but current detection methods are subject to limitations that adversely impact their utility for forensic analysis. We have developed a novel method for genotyping both single and multiple SNPs that uses an intercalating dye and a probe labeled with a single fluorophore to affect a fluorescence energy transfer. Melting curve analysis is then used to distinguish true alleles from mismatched alleles. We term the new method dye probe fluorescence resonance energy transfer (dpFRET). In the current work, development proceeded at first with synthetic DNA template testing to establish proof of concept for the chemistry involved, followed by the design of polymerase chain reaction (PCR)-based genomic DNA assays to demonstrate potential forensic applications. The loci chosen for testing included both nuclear (MHC DRB) and mitochondrial DNA (cytochrome b) genes. A preliminary assessment of the sensitivity limits of the technology indicated that dpFRET was capable of accurately genotyping DNA from one single diploid cell equivalent. This technology could also potentially impact a wide range of nonforensic disciplines to aid in discovery, screening, and association of DNA sequence polymorphisms.

  10. Numerical examinations of simplified spondylodesis models concerning energy absorption in magnetic resonance imaging

    Directory of Open Access Journals (Sweden)

    Hadert Nicole

    2016-09-01

    Full Text Available Metallic implants in magnetic resonance imaging (MRI are a potential safety risk since the energy absorption may increase temperature of the surrounding tissue. The temperature rise is highly dependent on implant size. Numerical examinations can be used to calculate the energy absorption in terms of the specific absorption rate (SAR induced by MRI on orthopaedic implants. This research presents the impact of titanium osteosynthesis spine implants, called spondylodesis, deduced by numerical examinations of energy absorption in simplified spondylodesis models placed in 1.5 T and 3.0 T MRI body coils. The implants are modelled along with a spine model consisting of vertebrae and disci intervertebrales thus extending previous investigations [1], [2]. Increased SAR values are observed at the ends of long implants, while at the center SAR is significantly lower. Sufficiently short implants show increased SAR along the complete length of the implant. A careful data analysis reveals that the particular anatomy, i.e. vertebrae and disci intervertebrales, has a significant effect on SAR. On top of SAR profile due to the implant length, considerable SAR variations at small scale are observed, e.g. SAR values at vertebra are higher than at disc positions.

  11. Non-radiative resonance energy transfer in bi-polymer nanoparticles of fluorescent conjugated polymers.

    Science.gov (United States)

    Ozel, Ilkem Ozge; Ozel, Tuncay; Demir, Hilmi Volkan; Tuncel, Donus

    2010-01-18

    This work demonstrates the comparative studies of non-radiative resonance energy transfer in bi-polymer nanoparticles based on fluorescent conjugated polymers. For this purpose, poly[(9,9-dihexylfluorene) (PF) as a donor (D) and poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) as an acceptor (A) have been utilized, from which four different bi-polymer nanoparticle systems are designed and synthesized. Both, steady-state fluorescence spectra and time-resolved fluorescence measurements indicate varying energy transfer efficiencies from the host polymer PF to the acceptor polymer MEH-PPV depending on the D-A distances and structural properties of the nanoparticles. The first approach involves the preparation of PF and MEH-PPV nanoparticles separately and mixing them at a certain ratio. In the second approach, first PF and MEH-PPV solutions are mixed prior to nanoparticle formation and then nanoparticles are prepared from the mixture. Third and fourth approaches involve the sequential nanoparticle preparation. In the former, nanoparticles are prepared to have PF as a core and MEH-PPV as a shell. The latter is the reverse of the third in which the core is MEH-PPV and the shell is PF. The highest energy transfer efficiency recorded to be 35% is obtained from the last system, in which a PF layer is sequentially formed on MEH-PPV NPs.

  12. Nanophotonic enhancement of the Förster resonance energy-transfer rate with single nanoapertures.

    Science.gov (United States)

    Ghenuche, Petru; de Torres, Juan; Moparthi, Satish Babu; Grigoriev, Victor; Wenger, Jérôme

    2014-08-13

    Tailoring the light-matter interaction and the local density of optical states (LDOS) with nanophotonics provides accurate control over the luminescence properties of a single quantum emitter. This paradigm is also highly attractive to enhance the near-field Förster resonance energy transfer (FRET) between two fluorescent emitters. Despite the wide applications of FRET in nanosciences, using nanophotonics to enhance FRET has remained a debated and complex challenge. Here we demonstrate enhanced energy transfer within single donor-acceptor fluorophore pairs confined in single gold nanoapertures. Experiments monitoring both the donor and the acceptor emission photodynamics clearly establish a linear dependence of the FRET rate on the LDOS in nanoapertures, demonstrating that nanophotonics can be used to intensify the near-field energy transfer. Strikingly, we observe a significant six-fold increase in the FRET rate for large donor-acceptor separations exceeding 13 nm. Exciting opportunities are opened to investigate biochemical structures with donor-acceptor distances much beyond the classical Förster radius. Importantly, our approach is fully compatible with the detection of single biomolecules freely diffusing in water solution under physiological conditions.

  13. Fluorescence resonance energy transfer in a binary organic nanoparticle system and its application.

    Science.gov (United States)

    Wu, Meng; Xu, Xinjun; Wang, Jinshan; Li, Lidong

    2015-04-22

    Fluorescent organic nanoparticles have a much better photostability than molecule-based probes. Here, we report a simple strategy to detect chemicals and biomolecules by a binary nanoparticle system based on fluorescence resonance energy transfer (FRET). Poly(9,9-di-n-octylfluorenyl-2,7-diyl) (PFO, energy donor) and poly [2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV, energy acceptor) are utilized to prepare the binary nanoparticle system through a reprecipitation method. Since the FRET process is strongly distance-dependent, a change in the interparticle distance between the two kinds of nanoparticles after introduction of analytes will alter the FRET efficiency. The response of the binary nanoparticle system to cationic polyelectrolytes was investigated by monitoring the FRET efficiency from PFO to MEH-PPV nanoparticles and the fluorescence color of the nanoparticle solutions. Furthermore, the cationic polyelectrolyte pretreated binary nanoparticle system can be used to detect DNA by desorption of nanoparticles from the polyelectrolyte's chains and the detection concentration can go down to 10(-14) M. Thus, the binary nanoparticle system shows great promise for applications in chemical sensing or biosensing.

  14. Measurement and Interpretation of Fermion-Pair Production at LEP energies above the Zo Resonance

    CERN Document Server

    Abdallah, J.; Adam, W.; Adzic, P.; Albrecht, T.; Alderweireld, T.; Alemany-Fernandez, R.; Allmendinger, T.; Allport, P.P.; Amaldi, U.; Amapane, N.; Amato, S.; Anashkin, E.; Andreazza, A.; Andringa, S.; Anjos, N.; Antilogus, P.; Apel, W.-D.; Arnoud, Y.; Ask, S.; Asman, B.; Augustin, J.E.; Augustinus, A.; Baillon, P.; Ballestrero, A.; Bambade, P.; Barbier, R.; Bardin, D.; Barker, G.J.; Baroncelli, A.; Battaglia, M.; Baubillier, M.; Becks, K.-H.; Begalli, M.; Behrmann, A.; Ben-Haim, E.; Benekos, N.; Benvenuti, A.; Berat, C.; Berggren, M.; Berntzon, L.; Bertrand, D.; Besancon, M.; Besson, N.; Bloch, D.; Blom, M.; Bluj, M.; Bonesini, M.; Boonekamp, M.; Booth, P.S.L.; Borisov, G.; Botner, O.; Bouquet, B.; Bowcock, T.J.V.; Boyko, I.; Bracko, M.; Brenner, R.; Brodet, E.; Bruckman, P.; Brunet, J.M.; Buschmann, P.; Calvi, M.; Camporesi, T.; Canale, V.; Carena, F.; Castro, Nuno Filipe; Cavallo, F.; Chapkin, M.; Charpentier, Ph.; Checchia, P.; Chierici, R.; Chliapnikov, P.; Chudoba, J.; Chung, S.U.; Cieslik, K.; Collins, P.; Contri, R.; Cosme, G.; Cossutti, F.; Costa, M.J.; Crennell, D.; Cuevas, J.; D'Hondt, J.; Dalmau, J.; da Silva, T.; Da Silva, W.; Della Ricca, G.; De Angelis, A.; De Boer, W.; De Clercq, C.; De Lotto, B.; De Maria, N.; De Min, A.; de Paula, L.; Di Ciaccio, L.; Di Simone, A.; Doroba, K.; Drees, J.; Eigen, G.; Ekelof, T.; Ellert, M.; Elsing, M.; Espirito Santo, M.C.; Fanourakis, G.; Fassouliotis, D.; Feindt, M.; Fernandez, J.; Ferrer, A.; Ferro, F.; Flagmeyer, U.; Foeth, H.; Fokitis, E.; Fulda-Quenzer, F.; Fuster, J.; Gandelman, M.; Garcia, C.; Gavillet, Ph.; Gazis, Evangelos; Gokieli, R.; Golob, B.; Gomez-Ceballos, G.; Goncalves, P.; Graziani, E.; Grosdidier, G.; Grzelak, K.; Guy, J.; Haag, C.; Hallgren, A.; Hamacher, K.; Hamilton, K.; Haug, S.; Hauler, F.; Hedberg, V.; Hennecke, M.; Herr, H.; Hoffman, J.; Holmgren, S.-O.; Holt, P.J.; Houlden, M.A.; Hultqvist, K.; Jackson, John Neil; Jarlskog, G.; Jarry, P.; Jeans, D.; Johansson, Erik Karl; Johansson, P.D.; Jonsson, P.; Joram, C.; Jungermann, L.; Kapusta, F.; Katsanevas, S.; Katsoufis, E.; Kernel, G.; Kersevan, B.P.; Kerzel, U.; King, B.T.; Kjaer, N.J.; Kluit, P.; Kokkinias, P.; Kourkoumelis, C.; Kouznetsov, O.; Krumstein, Z.; Kucharczyk, M.; Lamsa, J.; Leder, G.; Ledroit, Fabienne; Leinonen, L.; Leitner, R.; Lemonne, J.; Lepeltier, V.; Lesiak, T.; Liebig, W.; Liko, D.; Lipniacka, A.; Lopes, J.H.; Lopez, J.M.; Loukas, D.; Lutz, P.; Lyons, L.; MacNaughton, J.; Malek, A.; Maltezos, S.; Mandl, F.; Marco, J.; Marco, R.; Marechal, B.; Margoni, M.; Marin, J.-C.; Mariotti, C.; Markou, A.; Martinez-Rivero, C.; Masik, J.; Mastroyiannopoulos, N.; Matorras, F.; Matteuzzi, C.; Mazzucato, F.; Mazzucato, M.; Nulty, R.Mc; Meroni, C.; Migliore, E.; Mitaroff, W.; Mjoernmark, U.; Moa, T.; Moch, M.; Monig, Klaus; Monge, R.; Montenegro, J.; Moraes, D.; Moreno, S.; Morettini, P.; Mueller, U.; Muenich, K.; Mulders, M.; Mundim, L.; Murray, W.; Muryn, B.; Myatt, G.; Myklebust, T.; Nassiakou, M.; Navarria, F.; Nawrocki, K.; Nicolaidou, R.; Nikolaenko, V.; Nikolenko, M.; Oblakowska-Mucha, A.; Obraztsov, V.; Olshevski, A.; Onofre, A.; Orava, R.; Osterberg, K.; Ouraou, A.; Oyanguren, A.; Paganoni, M.; Paiano, S.; Palacios, J.P.; Palka, H.; Papadopoulou, Th.D.; Pape, L.; Parkes, C.; Parodi, F.; Parzefall, U.; Passeri, A.; Passon, O.; Peralta, L.; Perepelitsa, V.; Perrotta, A.; Petrolini, A.; Piedra, J.; Pieri, L.; Pierre, F.; Pimenta, M.; Piotto, E.; Podobnik, T.; Poireau, V.; Pol, M.E.; Polok, G.; Pozdniakov, V.; Pukhaeva, N.; Pullia, A.; Rames, J.; Read, A.; Rebecchi, P.; Rehn, J.; Reid, D.; Reinhardt, R.; Renton, P.; Richard, F.; Ridky, J.; Rivero, M.; Rodriguez, D.; Romero, A.; Ronchese, P.; Roudeau, P.; Rovelli, T.; Ruhlmann-Kleider, V.; Ryabtchikov, D.; Sadovsky, A.; Salmi, L.; Salt, J.; Sander, C.; Savoy-Navarro, A.; Schwickerath, U.; Segar, A.; Sekulin, R.; Siebel, M.; Sisakian, A.; Smadja, G.; Smirnova, O.; Sokolov, A.; Sopczak, A.; Sosnowski, R.; Spassov, T.; Stanitzki, M.; Stocchi, A.; Strauss, J.; Stugu, B.; Szczekowski, M.; Szeptycka, M.; Szumlak, T.; Tabarelli, T.; Taffard, A.C.; Tegenfeldt, F.; Timmermans, Jan; Tkatchev, L.; Tobin, M.; Todorovova, S.; Tome, B.; Tonazzo; Tortosa, P.; Travnicek, P.; Treille, D.; Tristam, G.; Trochimczuk, M.; Troncon, C.; Turluer, M.-L.; Tyapkin, I.A.; Tyapkin, P.; Tzamarias, S.; Uvarov, V.; Valenti, G.; Van Dam, Piet; Van Eldik, J.; van Remortel, N.; Van Vulpen, I.; Vegni, G.; Veloso, F.; Venus, W.; Verdier, P.; Verzi, V.; Vilanova, D.; Vitale, L.; Vrba, V.; Wahlen, H.; Washbrook, A.J.; Weiser, C.; Wicke, D.; Wickens, J.; Wilkinson, G.; Winter, M.; Witek, M.; Yushchenko, O.; Zalewska, A.; Zalewski, P.; Zavrtanik, D.; Zhuravlov, V.; Zimine, N.I.; Zintchenko, Z.; Zupan, M.

    2006-01-01

    This paper presents DELPHI measurements and interpretations of cross-sections, forward-backward asymmetries, and angular distributions, for the e+e- -> ffbar process for centre-of-mass energies above the Z resonance, from sqrt(s) ~ 130 - 207 GeV at the LEP collider. The measurements are consistent with the predictions of the Standard Model and are used to study a variety of models including the S-Matrix ansatz for e+e- -> ffbar scattering and several models which include physics beyond the Standard Model: the exchange of Z' bosons, contact interactions between fermions, the exchange of gravitons in large extra dimensions and the exchange of sneutrino in R-parity violating supersymmetry.

  15. Note: High-efficiency broadband acoustic energy harvesting using Helmholtz resonator and dual piezoelectric cantilever beams

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Aichao; Li, Ping, E-mail: liping@cqu.edu.cn; Wen, Yumei; Lu, Caijiang; Peng, Xiao; He, Wei; Zhang, Jitao; Wang, Decai; Yang, Feng [Research Center of Sensors and Instruments, College of Optoelectronic Engineering, Chongqing University, Chongqing 400044 (China)

    2014-06-15

    A high-efficiency broadband acoustic energy harvester consisting of a compliant-top-plate Helmholtz resonator (HR) and dual piezoelectric cantilever beams is proposed. Due to the high mechanical quality factor of beams and the strong multimode coupling of HR cavity, top plate and beams, the high efficiency in a broad bandwidth is obtained. Experiment exhibits that the proposed harvester at 170–206 Hz has 28–188 times higher efficiency than the conventional harvester using a HR with a piezoelectric composite diaphragm. For input acoustic pressure of 2.0 Pa, the proposed harvester exhibits 0.137–1.43 mW output power corresponding to 0.035–0.36 μW cm{sup −3} volume power density at 170–206 Hz.

  16. On the role of sigma-particle and other resonances in low-energy mesonic processes

    Energy Technology Data Exchange (ETDEWEB)

    Shabalin, Evgeny [Institute of Theoretical and Experimental Physics, Moscow (Russian Federation)

    2000-12-01

    Using the principle of the most conformity of the QCD and real world objects we argue that {sigma}-meson and other q-barq scalar mesons are the natural elements of the Chiral Theory. An existence of the light isoscalar {sigma}-meson allows to understand many interesting features of {kappa}-decays. In {pi}{pi} scattering, {sigma} exchange gives the main contribution into phase shifts at energy near threshold and together with intermediate spin 1 and spin 2 resonances allows to obtain a good description of the phase shifts {delta}{sub 0}{sup 0}(s), {delta}{sub 0}{sup 2}(s), {delta}{sub 1}{sup 1}(s), {delta}{sub 2}{sup 0}(s) and {delta}{sub 2}{sup 2}(s) for {radical}s{<=}1 GeV. (author)

  17. Biosensing with Förster Resonance Energy Transfer Coupling between Fluorophores and Nanocarbon Allotropes

    Directory of Open Access Journals (Sweden)

    Shaowei Ding

    2015-06-01

    Full Text Available Nanocarbon allotropes (NCAs, including zero-dimensional carbon dots (CDs, one-dimensional carbon nanotubes (CNTs and two-dimensional graphene, exhibit exceptional material properties, such as unique electrical/thermal conductivity, biocompatibility and high quenching efficiency, that make them well suited for both electrical/electrochemical and optical sensors/biosensors alike. In particular, these material properties have been exploited to significantly enhance the transduction of biorecognition events in fluorescence-based biosensing involving Förster resonant energy transfer (FRET. This review analyzes current advances in sensors and biosensors that utilize graphene, CNTs or CDs as the platform in optical sensors and biosensors. Widely utilized synthesis/fabrication techniques, intrinsic material properties and current research examples of such nanocarbon, FRET-based sensors/biosensors are illustrated. The future outlook and challenges for the research field are also detailed.

  18. Note: High-efficiency broadband acoustic energy harvesting using Helmholtz resonator and dual piezoelectric cantilever beams.

    Science.gov (United States)

    Yang, Aichao; Li, Ping; Wen, Yumei; Lu, Caijiang; Peng, Xiao; He, Wei; Zhang, Jitao; Wang, Decai; Yang, Feng

    2014-06-01

    A high-efficiency broadband acoustic energy harvester consisting of a compliant-top-plate Helmholtz resonator (HR) and dual piezoelectric cantilever beams is proposed. Due to the high mechanical quality factor of beams and the strong multimode coupling of HR cavity, top plate and beams, the high efficiency in a broad bandwidth is obtained. Experiment exhibits that the proposed harvester at 170-206 Hz has 28-188 times higher efficiency than the conventional harvester using a HR with a piezoelectric composite diaphragm. For input acoustic pressure of 2.0 Pa, the proposed harvester exhibits 0.137-1.43 mW output power corresponding to 0.035-0.36 μW cm(-3) volume power density at 170-206 Hz.

  19. Toward dynamic structural biology: Two decades of single-molecule Förster resonance energy transfer.

    Science.gov (United States)

    Lerner, Eitan; Cordes, Thorben; Ingargiola, Antonino; Alhadid, Yazan; Chung, SangYoon; Michalet, Xavier; Weiss, Shimon

    2018-01-19

    Classical structural biology can only provide static snapshots of biomacromolecules. Single-molecule Förster resonance energy transfer (smFRET) paved the way for studying dynamics in macromolecular structures under biologically relevant conditions. Since its first implementation in 1996, smFRET experiments have confirmed previously hypothesized mechanisms and provided new insights into many fundamental biological processes, such as DNA maintenance and repair, transcription, translation, and membrane transport. We review 22 years of contributions of smFRET to our understanding of basic mechanisms in biochemistry, molecular biology, and structural biology. Additionally, building on current state-of-the-art implementations of smFRET, we highlight possible future directions for smFRET in applications such as biosensing, high-throughput screening, and molecular diagnostics. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  20. Biosensing with Förster Resonance Energy Transfer Coupling between Fluorophores and Nanocarbon Allotropes.

    Science.gov (United States)

    Ding, Shaowei; Cargill, Allison A; Das, Suprem R; Medintz, Igor L; Claussen, Jonathan C

    2015-06-23

    Nanocarbon allotropes (NCAs), including zero-dimensional carbon dots (CDs), one-dimensional carbon nanotubes (CNTs) and two-dimensional graphene, exhibit exceptional material properties, such as unique electrical/thermal conductivity, biocompatibility and high quenching efficiency, that make them well suited for both electrical/electrochemical and optical sensors/biosensors alike. In particular, these material properties have been exploited to significantly enhance the transduction of biorecognition events in fluorescence-based biosensing involving Förster resonant energy transfer (FRET). This review analyzes current advances in sensors and biosensors that utilize graphene, CNTs or CDs as the platform in optical sensors and biosensors. Widely utilized synthesis/fabrication techniques, intrinsic material properties and current research examples of such nanocarbon, FRET-based sensors/biosensors are illustrated. The future outlook and challenges for the research field are also detailed.

  1. Enhancement of Resonant Energy Transfer Due to an Evanescent Wave from the Metal

    Energy Technology Data Exchange (ETDEWEB)

    Poudel, Amrit [Department; Chen, Xin [Center of Nanomaterials; Ratner, Mark A. [Department

    2016-02-29

    The high density of evanescent modes in the vicinity of a metal leads to enhancement of the near-field Förster resonant energy transfer (FRET) rate. We present a classical approach to calculate the FRET rate based on the dyadic Green’s function of an arbitrary dielectric environment and consider the nonlocal limit of material permittivity in the case of the metallic half-space and thin film. In a dimer system, we find that the FRET rate is enhanced due to shared evanescent photon modes bridging a donor and an acceptor. Furthermore, a general expression for the FRET rate for multimer systems is derived. The presence of a dielectric environment and the path interference effect enhance the transfer rate, depending on the combination of distance and geometry.

  2. Biosensing with Förster Resonance Energy Transfer Coupling between Fluorophores and Nanocarbon Allotropes

    Science.gov (United States)

    Ding, Shaowei; Cargill, Allison A.; Das, Suprem R.; Medintz, Igor L.; Claussen, Jonathan C.

    2015-01-01

    Nanocarbon allotropes (NCAs), including zero-dimensional carbon dots (CDs), one-dimensional carbon nanotubes (CNTs) and two-dimensional graphene, exhibit exceptional material properties, such as unique electrical/thermal conductivity, biocompatibility and high quenching efficiency, that make them well suited for both electrical/electrochemical and optical sensors/biosensors alike. In particular, these material properties have been exploited to significantly enhance the transduction of biorecognition events in fluorescence-based biosensing involving Förster resonant energy transfer (FRET). This review analyzes current advances in sensors and biosensors that utilize graphene, CNTs or CDs as the platform in optical sensors and biosensors. Widely utilized synthesis/fabrication techniques, intrinsic material properties and current research examples of such nanocarbon, FRET-based sensors/biosensors are illustrated. The future outlook and challenges for the research field are also detailed. PMID:26110411

  3. Judgment of pure fermented soy sauce by fluorescence resonance energy transfer of OPA-tryptophan adduct.

    Science.gov (United States)

    Gao, You-Syuan; Hsieh, Bo-Chuan; Cheng, Tzong-Jih; Chen, Richie L C

    2015-07-01

    Tryptophan was detected with a flow-injection manifold after reacting with mM order of fluorogenic o-phthalaldehyde (OPA)/thiol reagent (pH 10.0) in the carrier stream (0.63 mL/min). Based on the intra-molecular fluorescence resonance energy transfer of OPA-tryptophan adduct, the difference in fluorescence intensity obtained at 280 and 300 nm excitation was used to detect tryptophan content with satisfactory precision (CVtryptophan will decompose during manufacturing non-fermented soy sauce by acid-hydrolysis procedure, the method was used to discriminate pure fermented soy sauces, adulterated soy sauces and chemical soy sauces in less than 5 min. The ratio of tryptophan to total amino acid content served as the index for the judgment, and the results were validated by capillary electrophoresis. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Fluorescence Resonance Energy Transfer in Quantum Dot-Protein Kinase Assemblies

    Directory of Open Access Journals (Sweden)

    Ibrahim Yildiz

    2007-01-01

    Full Text Available In search of viable strategies to identify selective inhibitors of protein kinases, we have designed a binding assay to probe the interactions of human phosphoinositide-dependent protein kinase-1 (PDK1 with potential ligands. Our protocol is based on fluorescence resonance energy transfer (FRET between semiconductor quantum dots (QDs and organic dyes. Specifically, we have expressed and purified the catalytic kinase domain of PDK1 with an N-terminal histidine tag [His6-PDK1(ΔPH]. We have conjugated this construct to CdSe-ZnS core-shell QDs coated with dihydrolipoic acid (DHLA and tested the response of the resulting assembly to a molecular dyad incorporating an ATP ligand and a BODIPY chromophore. The supramolecular association of the BODIPY-ATP dyad with the His6-PDK1(ΔPH-QD assembly encourages the transfer of energy from the QDs to the BODIPY dyes upon excitation. The addition of ATP results in the displacement of BODIPY-ATP from the binding domain of the His6-PDK1(ΔPH conjugated to the nanoparticles. The competitive binding, however, does not prevent the energy transfer process. A control experiment with QDs, lacking the His6-PDK1(ΔPH, indicates that the BODIPY-ATP dyad adsorbs nonspecifically on the surface of the nanoparticles, promoting the transfer of energy from the CdSe core to the adsorbed BODIPY dyes. Thus, the implementation of FRET-based assays to probe the binding domain of PDK1 with luminescent QDs requires the identification of energy acceptors unable to interact nonspecifically with the surface of the nanoparticles.

  5. Highly sensitive determination of antimony in food by resonance Rayleigh scattering-energy transfer between grapheme oxide and I3(.).

    Science.gov (United States)

    Wen, Guiqing; Zhang, Xinghui; Li, Yuan; Luo, Yanghe; Liang, Aihui; Jiang, Zhiliang

    2017-01-01

    Sb(III) was reduced to SbH3 gas and introduced to the I3(-)-grapheme oxide (GO) or I3(-)-silver nanorod (AgNR)-Victoria blue B (VBB) solutions. Resonance Rayleigh scattering energy transfer (RRS-ET) occurred between the donor GO and the acceptor I3(-) due to the overlap between the absorption peak of I3(-) and RRS peak of GO. When I3(-) was reduced by SbH3, RRS-ET weakened and the RRS intensity enhanced. The increased RRS intensity was linear to Sb concentration in the range of 2.1-376.6μg/L. In the I3(-)-AgNR-VBB solution, I3(-) combined with VBB to form VBB-I3 and there was a weak surface-enhanced Raman scattering (SERS) effect. When SbH3 reduced I3(-), the SERS intensity increased due to the release of SERS active VBB. The enhanced SERS intensity was linear for Sb concentration in the range of 8.4-292.9μg/L. The RRS-ET method was applied for determination of Sb in food with satisfactory results. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Competitive binding assay using fluorescence resonance energy transfer for the identification of calmodulin antagonists.

    Science.gov (United States)

    Sharma, Bethel; Deo, Sapna K; Bachas, Leonidas G; Daunert, Sylvia

    2005-01-01

    The ubiquitous calcium regulating protein calmodulin (CaM) has been utilized as a model drug target in the design of a competitive binding fluorescence resonance energy transfer assay for pharmacological screening. The protein was labeled by covalently attaching the thiol-reactive fluorophore, N-[2-(1-maleimidyl)ethyl]-7-(diethylamino)coumarin-3-carboxamide (MDCC) to an engineered C-terminal cysteine residue. Binding of the environmentally sensitive hydrophobic probe 2,6-anilinonaphthalene sulfonate (2,6-ANS) to CaM could be monitored by an increase in the fluorescence emission intensity of the 2,6-ANS. Evidence of fluorescence resonance energy transfer (FRET) from 2,6-ANS (acting as a donor) to MDCC (the acceptor in this system) was also observed; fluorescence emission representative of MDCC could be seen after samples were excited at a wavelength specific for 2,6-ANS. The FRET signal was monitored as a function of the concentration of calmodulin antagonists in solution. Calibration curves for both a selection of small molecules and a series of peptides based upon known CaM-binding domains were obtained using this system. The assay demonstrated dose-dependent antagonism by analytes known to hinder the biological activity of CaM. These data indicate that the presence of molecules known to bind CaM interfere with the ability of FRET to occur, thus leading to a concentration-dependent decrease of the ratio of acceptor:donor fluorescence emission. This assay can serve as a general model for the development of other protein binding assays intended to screen for molecules with preferred binding activity.

  7. Wireless Energy Transfer Using Resonant Magnetic Induction for Electric Vehicle Charging Application

    Science.gov (United States)

    Dahal, Neelima

    The research work for this thesis is based on utilizing resonant magnetic induction for wirelessly charging electric vehicles. The background theory for electromagnetic induction between two conducting loops is given and it is shown that an RLCequivalent circuit can be used to model the loops. An analysis of the equivalent circuit is used to show how two loosely coupled loops can be made to exchange energy efficiently by operating them at a frequency which is the same as the resonant frequency of both. Furthermore, it is shown that the efficiency is the maximum for critical coupling (determined by the quality factors of the loops), and increasing the coupling beyond critical coupling causes double humps to appear in the transmission efficiency versus frequency spectrum. In the experiment, as the loops are brought closer together which increases the coupling between them, doubles humps, as expected from the equivalent circuit analysis is seen. Two models for wireless energy transfer are identified: basic model and array model. The basic model consists of the two loosely coupled loops, the transmitter and the receiver. The array model consists of a 2 x 2 array of the transmitter and three parasites, and the receiver. It is shown that the array model allows more freedom for receiver placement at the cost of degraded transmission efficiency compared to the basic model. Another important part of the thesis is software validation. HFSS-IE and 4NEC2 are the software tools used and the simulation results for wire antennas are compared against references obtained from a textbook and a PhD dissertation. It is shown that the simulations agree well with the references and also with each other.

  8. Trans-projected-range gettering of copper in high-energy ion-implanted silicon

    Science.gov (United States)

    Gueorguiev, Y. M.; Kögler, R.; Peeva, A.; Mücklich, A.; Panknin, D.; Yankov, R. A.; Skorupa, W.

    2000-12-01

    Strong gettering of Cu atoms beyond the projected ion range RP has been found in single-crystal Si implanted with P+ and As+ ions at MeV energies. We call this phenomenon the "trans-RP effect." The formation of a separate Cu gettering band below RP, as detected by secondary ion mass spectrometry, indicates the presence of a significant amount of defects therein. These defects have not been detected by transmission electron microscopy and we suggest that they are small interstitial clusters. The amount of Cu atoms gettered beyond RP is, particularly for the P implants, much greater than that in the gettering layer at RP, indicating that the gettering ability of the point defects beyond RP is higher than that of the extended defects at RP. A mechanism responsible for their formation and clustering in the trans-RP region is proposed, and an explanation is given of the differences in the results for the P and As implants.

  9. Harnessing big data for estimating the energy consumption and driving range of electric vehicles

    DEFF Research Database (Denmark)

    Fetene, Gebeyehu Manie; Kaplan, Sigal; Mabit, Stefan Lindhard

    2017-01-01

    electric vehicles (BEVs) and provides insight into the factors that affect their energy consumption by harnessing big data from real-world driving. The analysis relied on four data sources: (i) driving patterns collected from 741 drivers over a two-year period; (ii) drivers’ characteristics; (iii) road...... type; (iv) weather conditions. The results of the analysis measure the mean ECR of BEVs at 0.183 kW h/km, underline a 34% increase in ECR and a 25% decrease in driving range in the winter with respect to the summer, and suggest the electricity tariff for BEVs to be cost efficient with respect...... to conventional ones. Moreover, the results of the analysis show that driving speed, acceleration and temperature have non-linear effects on the ECR, while season and precipitation level have a strong linear effect. The econometric model of the ECR of BEVs suggests that the optimal driving speed is between 45...

  10. Resonance Strength Measurement at Astrophysical Energies: The 17O(p,α14N Reaction Studied via THM

    Directory of Open Access Journals (Sweden)

    Sergi M.L.

    2016-01-01

    Full Text Available In recent years, the Trojan Horse Method (THM has been used to investigate the low-energy cross sections of proton-induced reactions on 17O nuclei, overcoming extrapolation procedures and enhancement effects due to electron screening. We will report on the indirect study of the 17O(p,α14N reaction via the Trojan Horse Method by applying the approach developed for extracting the resonance strength of narrow resonance in the ultralow energy region. The mean value of the strengths obtained in the two measurements was calculated and compared with the direct data available in literature.

  11. Characterization of G-protein coupled receptor kinase interaction with the neurokinin-1 receptor using bioluminescence resonance energy transfer

    DEFF Research Database (Denmark)

    Jorgensen, Rasmus; Holliday, Nicholas D; Hansen, Jakob L

    2007-01-01

    To analyze the interaction between the neurokinin-1 (NK-1) receptor and G-protein coupled receptor kinases (GRKs), we performed bioluminescence resonance energy transfer(2) (BRET(2)) measurements between the family A NK-1 receptor and GRK2 and GRK5 as well as their respective kinase-inactive muta......To analyze the interaction between the neurokinin-1 (NK-1) receptor and G-protein coupled receptor kinases (GRKs), we performed bioluminescence resonance energy transfer(2) (BRET(2)) measurements between the family A NK-1 receptor and GRK2 and GRK5 as well as their respective kinase...

  12. Designing an extended energy range single-sphere multi-detector neutron spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Ros, J.M., E-mail: jm.gomezros@ciemat.es [CIEMAT, Av. Complutense 40, 28040 Madrid (Spain); IFNF-LNF, U.F. Fisica Sanitaria, via E. Fermi n. 40, 00044 Frascati (Italy); Bedogni, R. [IFNF-LNF, U.F. Fisica Sanitaria, via E. Fermi n. 40, 00044 Frascati (Italy); Moraleda, M. [CIEMAT, Av. Complutense 40, 28040 Madrid (Spain); Esposito, A. [IFNF-LNF, U.F. Fisica Sanitaria, via E. Fermi n. 40, 00044 Frascati (Italy); Pola, A.; Introini, M.V. [Politecnico di Milano, Dipartimento di Energia, via Ponzio 34/3, 20133 Milano (Italy); Mazzitelli, G.; Quintieri, L.; Buonomo, B. [IFNF-LNF, U.F. Fisica Sanitaria, via E. Fermi n. 40, 00044 Frascati (Italy)

    2012-06-11

    This communication describes the design specifications for a neutron spectrometer consisting of 31 thermal neutron detectors, namely Dysprosium activation foils, embedded in a 25 cm diameter polyethylene sphere which includes a 1 cm thick lead shell insert that degrades the energy of neutrons through (n,xn) reactions, thus allowing to extension of the energy range of the response up to hundreds of MeV neutrons. The new spectrometer, called SP{sup 2} (SPherical SPectrometer), relies on the same detection mechanism as that of the Bonner Sphere Spectrometer, but with the advantage of determining the whole neutron spectrum in a single exposure. The Monte Carlo transport code MCNPX was used to design the spectrometer in terms of sphere diameter, number and position of the detectors, position and thickness of the lead shell, as well as to obtain the response matrix for the final configuration. This work focuses on evaluating the spectrometric capabilities of the SP{sup 2} design by simulating the exposure of SP{sup 2} in neutron fields representing different irradiation conditions (test spectra). The simulated SP{sup 2} readings were then unfolded with the FRUIT unfolding code, in the absence of detailed pre-information, and the unfolded spectra were compared with the known test spectra. The results are satisfactory and allowed approving the production of a prototypal spectrometer.

  13. A portable and wide energy range semiconductor-based neutron spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Hoshor, C.B. [Department of Physics, University of Missouri, Kansas City, MO (United States); Oakes, T.M. [Nuclear Science and Engineering Institute, University of Missouri, Columbia, MO (United States); Myers, E.R.; Rogers, B.J.; Currie, J.E.; Young, S.M.; Crow, J.A.; Scott, P.R. [Department of Physics, University of Missouri, Kansas City, MO (United States); Miller, W.H. [Nuclear Science and Engineering Institute, University of Missouri, Columbia, MO (United States); Missouri University Research Reactor, Columbia, MO (United States); Bellinger, S.L. [Department of Mechanical and Nuclear Engineering, Kansas State University, Manhattan, KS (United States); Sobering, T.J. [Electronics Design Laboratory, Kansas State University, Manhattan, KS (United States); Fronk, R.G.; Shultis, J.K.; McGregor, D.S. [Department of Mechanical and Nuclear Engineering, Kansas State University, Manhattan, KS (United States); Caruso, A.N., E-mail: carusoan@umkc.edu [Department of Physics, University of Missouri, Kansas City, MO (United States)

    2015-12-11

    Hand-held instruments that can be used to passively detect and identify sources of neutron radiation—either bare or obscured by neutron moderating and/or absorbing material(s)—in real time are of interest in a variety of nuclear non-proliferation and health physics applications. Such an instrument must provide a means to high intrinsic detection efficiency and energy-sensitive measurements of free neutron fields, for neutrons ranging from thermal energies to the top end of the evaporation spectrum. To address and overcome the challenges inherent to the aforementioned applications, four solid-state moderating-type neutron spectrometers of varying cost, weight, and complexity have been designed, fabricated, and tested. The motivation of this work is to introduce these novel human-portable instruments by discussing the fundamental theory of their operation, investigating and analyzing the principal considerations for optimal instrument design, and evaluating the capability of each of the four fabricated spectrometers to meet the application needs.

  14. Range-energy relation, range straggling and response function of CsI(Tl), BGO and GSO(Ce) scintillators for light ions

    CERN Document Server

    Avdeichikov, V; Jakobsson, B; Rodin, A M; Ter-Akopian, G M

    2000-01-01

    Range-energy relations and range straggling of sup 1 sup , sup 2 sup , sup 3 H and sup 4 sup , sup 6 He isotopes with the energy approx 50A MeV are measured for the CsI(Tl), BGO and GSO(Ce) scintillators with an accuracy better than 0.2% and 5%, respectively. The Si-Sci/PD telescope was exposed to secondary beams from the mass separator ACCULINNA. The experimental technique is based on the registration of the 'jump' in the amplitude of the photodiode signal for ions passing through the scintillation crystal. Light response of the scintillators for ions 1<=Z<=4 is measured in energy range (5-50)A MeV, the results are in good agreement with calculations based on Birks model. The energy loss straggling for particles with DELTA E/E=0.01-0.50 and mass up to A=10 in 286 mu m DELTA E silicon detector is studied and compared with theoretical prescriptions. The results allow a precise absolute calibration of the scintillation crystal and to optimize the particle identification by the DELTA E-E(Sci/PD) method.

  15. High accuracy 235U(n,f data in the resonance energy region

    Directory of Open Access Journals (Sweden)

    Paradela C.

    2016-01-01

    Full Text Available The 235U neutron-induced cross section is widely used as reference cross section for measuring other fission cross sections, but in the resonance region it is not considered as an IAEA standard because of the scarce experimental data covering the full region. In this work, we deal with a new analysis of the experimental data obtained with a detection setup based on parallel plate ionization chambers (PPACs at the CERN n_TOF facility in the range from 1 eV to 10 keV. The relative cross section has been normalised to the IAEA value in the region between 7.8 and 11 eV, which is claimed as well-known. Comparison with the ENDF/B-VII evaluation and the IAEA reference file from 100 eV to 10 keV are provided.

  16. Beyond the Förster formulation for resonance energy transfer: the role of dark states.

    Science.gov (United States)

    Sissa, C; Manna, A K; Terenziani, F; Painelli, A; Pati, S K

    2011-07-28

    Resonance Energy Transfer (RET) is investigated in pairs of charge-transfer (CT) chromophores. CT chromophores are an interesting class of π conjugated chromophores decorated with one or more electron-donor and acceptor groups in polar (D-π-A), quadrupolar (D-π-A-π-D or A-π-D-π-A) or octupolar (D(-π-A)(3) or A(-π-D)(3)) structures. Essential-state models accurately describe low-energy linear and nonlinear spectra of CT-chromophores and proved very useful to describe spectroscopic effects of electrostatic interchromophore interactions in multichromophoric assemblies. Here we apply the same approach to describe RET between CT-chromophores. The results are quantitatively validated by an extensive comparison with time-dependent density functional theory (TDDFT) calculations, confirming that essential-state models offer a simple and reliable approach for the calculation of electrostatic interchromophore interactions. This is an important result since it sets the basis for more refined treatments of RET: essential-state models are in fact easily extended to account for molecular vibrations in truly non-adiabatic approaches and to account for inhomogeneous broadening effects due to polar solvation. Optically forbidden (dark) states of quadrupolar and octupolar chromophores offer an interesting opportunity to verify the reliability of the dipolar approximation. In striking contrast with the dipolar approximation that strictly forbids RET towards or from dark states, our results demonstrate that dark states can take an active role in RET with interaction energies that, depending on the relative orientation of the chromophores, can be even larger than those relevant to allowed states. Essential-state models, whose predictions are quantitatively confirmed by TDDFT results, allow us to relate RET interaction energies towards allowed and dark states to the supramolecular symmetry of the RET-pair, offering reliable design strategies to optimize RET-interactions. This

  17. Cu-Fe-S Nanocrystals Exhibiting Tunable Localized Surface Plasmon Resonance in the Visible to NIR Spectral Ranges.

    Science.gov (United States)

    Gabka, Grzegorz; Bujak, Piotr; Ostrowski, Andrzej; Tomaszewski, Waldemar; Lisowski, Wojciech; Sobczak, Janusz W; Pron, Adam

    2016-07-05

    Cu-Fe-S nanocrystals exhibiting a strong localized surface plasmon resonance (LSPR) effect were synthesized for the first time. The elaborated reproducible preparation procedure involved copper(II) oleate, iron(III) stearate, and sulfur powder dissolved in oleylamine (OLA) as precursors. The wavelength of the plasmonic resonance maximum could be tuned by changing the Cu/Fe ratio in the resulting nanocrystals, being the most energetic for the 1:1 ratio (486 nm) and undergoing a bathochromic shift to ca. 1200 nm with an increase to 6:1. LSPR could also be observed in nanocrystals prepared from the same metal precursors and sulfur powder dissolved in 1-octadecene (ODE), provided that the sulfur precursor was taken in excess. Detailed analysis of the reaction mixture by chromatographic techniques, supplemented by mass spectrometry and (1)H NMR spectroscopy enabled the identification of the true chemical nature of the sulfur precursor in S/OLA, namely, (C18H35NH3(+))(C18H35NH-S8(-)), a reactive product of the reduction of elemental sulfur by the amine groups of OLA. In the case of the S/ODE precursor, the true precursors are much less reactive primary or secondary thioethers and dialkyl polysulfides.

  18. Modeling and characterization of double resonant tunneling diodes for application as energy selective contacts in hot carrier solar cells

    Science.gov (United States)

    Jehl, Zacharie; Suchet, Daniel; Julian, Anatole; Bernard, Cyril; Miyashita, Naoya; Gibelli, Francois; Okada, Yoshitaka; Guillemolles, Jean-Francois

    2017-02-01

    Double resonant tunneling barriers are considered for an application as energy selective contacts in hot carrier solar cells. Experimental symmetric and asymmetric double resonant tunneling barriers are realized by molecular beam epitaxy and characterized by temperature dependent current-voltage measurements. The negative differential resistance signal is enhanced for asymmetric heterostructures, and remains unchanged between low- and room-temperatures. Within Tsu-Esaki description of the tunnel current, this observation can be explained by the voltage dependence of the tunnel transmission amplitude, which presents a resonance under finite bias for asymmetric structures. This effect is notably discussed with respect to series resistance. Different parameters related to the electronic transmission of the structure and the influence of these parameters on the current voltage characteristic are investigated, bringing insights on critical processes to optimize in double resonant tunneling barriers applied to hot carrier solar cells.

  19. Low-energy d-d excitations in MnO studied by resonant x-ray fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Butorin, S.M.; Guo, J.; Magnuson, M. [Uppsala Univ. (Sweden)] [and others

    1997-04-01

    Resonant soft X-ray emission spectroscopy has been demonstrated to possess interesting abilities for studies of electronic structure in various systems, such as symmetry probing, alignment and polarization dependence, sensitivity to channel interference, etc. In the present abstract the authors focus on the feasibility of resonant soft X-ray emission to probe low energy excitations by means of resonant electronic X-ray Raman scattering. Resonant X-ray emission can be regarded as an inelastic scattering process where a system in the ground state is transferred to a low excited state via a virtual core excitation. The energy closeness to a core excitation of the exciting radiation enhances the (generally) low probability for inelastic scattering at these wavelengths. Therefore soft X-ray emission spectroscopy (in resonant electronic Raman mode) can be used to study low energy d-d excitations in transition metal systems. The involvement of the intermediate core state allows one to use the selection rules of X-ray emission, and the appearance of the elastically scattered line in the spectra provides the reference to the ground state.

  20. Design of coupled cavity with energy modulated electron cyclotron resonance ion source for materials irradiation research

    Directory of Open Access Journals (Sweden)

    Z. Wang (王智

    2012-05-01

    Full Text Available The surface topography of samples after irradiation with heavy ions, protons, and helium ions based on accelerators is an important issue in the study of materials irradiation. We have coupled the separated function radio frequency quadrupole (SFRFQ electrodes and the traditional RFQ electrodes into a single cavity that can provide a 0.8 MeV helium beam for our materials irradiation project. The higher accelerating efficiency has been verified by the successful commissioning of the prototype SFRFQ cavity. An energy modulated electron cyclotron resonance (ECR ion source can achieve a well-bunched beam by loading a sine wave voltage onto the extracted electrodes. Bunching is achieved without the need for an external bunch cavity, which can substantially reduce the cost of the system and the length of the beam line. The coupled RFQ-SFRFQ with an energy modulated ECR ion source will lead to a more compact accelerator system. The conceptual design of this novel structure is presented in this paper.

  1. Resonant tunneling diodes as energy-selective contacts used in hot-carrier solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Yasuhiko, E-mail: takeda@mosk.tytlabs.co.jp; Sugimoto, Noriaki [Toyota Central Research and Development Laboratories, Inc., 41-1, Yokomichi, Nagakute, Aichi 480-1192 (Japan); Ichiki, Akihisa [Green Mobility Collaborative Research Center, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Kusano, Yuya [Green Mobility Collaborative Research Center, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Toyota Motor Corp., 1200 Mishuku, Susono, Shizuoka 410-1193 (Japan); Motohiro, Tomoyoshi [Toyota Central Research and Development Laboratories, Inc., 41-1, Yokomichi, Nagakute, Aichi 480-1192 (Japan); Green Mobility Collaborative Research Center, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan)

    2015-09-28

    Among the four features unique to hot-carrier solar cells (HC-SCs): (i) carrier thermalization time and (ii) carrier equilibration time in the absorber, (iii) energy-selection width and (iv) conductance of the energy-selective contacts (ESCs), requisites of (i)-(iii) for high conversion efficiency have been clarified. We have tackled the remaining issues related to (iv) in the present study. The detailed balance model of HC-SC operation has been improved to involve a finite value of the ESC conductance to find the required values, which in turn has been revealed to be feasible using resonant tunneling diodes (RTDs) consisting of semiconductor quantum dots (QDs) and quantum wells (QWs) by means of a formulation to calculate the conductance of the QD- and QW-RTDs derived using the rigorous solutions of the effective-mass Hamiltonians. Thus, all of the four requisites unique to HC-SCs to achieve high conversion efficiency have been elucidated, and the two requisites related to the ESCs can be fulfilled using the QD- and QW-RTDs.

  2. Effect of medium chirality on the rate of resonance energy transfer.

    Science.gov (United States)

    Rodriguez, Justo J; Salam, A

    2011-05-12

    Resonance energy transfer (RET) between two chromophores in an absorptive and dispersive chiral medium is investigated using a quantum electrodynamical formulation. To accurately describe such an environment involves the introduction of electric displacement and auxiliary magnetic field operators that are solutions of the Drude-Born-Fedorov equations and the time-harmonic Maxwell equations. Perturbation theory within the electric and magnetic dipole approximation is used in the derivation of the probability amplitude for energy transfer. Expressions for the contributions to the RET rate arising from the pure electric dipole term, replacing one of the chiral chromophores by its corresponding enantiomer in the mixed electric-magnetic dipole term, and the pure magnetic dipole contribution are obtained. In the near-zone limit in a nonabsorptive medium, the medium chirality amplifies the pure electric dipole contribution to the rate relative to that in a racemic mixture and also increases the discriminatory contribution, but to a lesser extent relative to the pure electric dipole term. On the other hand, under the same conditions, the medium chirality does not affect the pure magnetic dipole contribution to the rate. Measurements of the rate could be used to obtain information on the magnitude of the chirality admittance or concentration of chiral species, by comparing with the rate in an environment comprised of a racemic mixture of the enantiomers. This method could allow for the analysis of macroscopically heterogeneous systems that are comprised of enantiomers and where the chromophores experiencing RET are located in regions of interest.

  3. Lanthanide-to-quantum dot Förster resonance energy transfer (FRET): Application for immunoassay.

    Science.gov (United States)

    Goryacheva, O A; Beloglazova, N V; Vostrikova, A M; Pozharov, M V; Sobolev, A M; Goryacheva, I Yu

    2017-03-01

    Förster resonance energy transfer (FRET) between lanthanide ion complexes (L) acting as donors and luminescent semiconductor quantum dots (QD) acting as acceptors is discussed in the terms of advantages and disadvantages for its application in immunoassay. L-QD-FRET is potentially a powerful tool that can be used to detect and confirm formation of immunocomplexes, but until now it had very limited practical analytical application. Therefore, the main aim of this review is to analyze all possibilities, advantages, and disadvantages of L-QD-FRET in immunoassay applications. Considering L and QD respectively applied as donor and acceptor, the most advantageous properties for analytical purposes are large decay time of L complexes and the high absorption of QD. L complexes' extremely long decay times make it possible to directly detect FRET through enhancement of QDs decay time as a result of energy transfer. Very high QD absorption predetermines extremely large Förster radii (ca. 10nm), which means that FRET can be utilized for proteins and protein complexes, such as antigen-antibody systems. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Resonant frequency stabilization technique in series-series contactless energy transfer systems

    Directory of Open Access Journals (Sweden)

    Marcinek M.

    2017-09-01

    Full Text Available A technique for stabilization of resonant frequency is proposed in this paper. An additional power circuit, a compensator that allows keeping constant resonance frequency was introduced by the authors. In the presented solution the resonant circuit frequency stabilization is achieved by forcing a zero phase shift between the current and the voltage of the main switching module.

  5. Charge-Shift Corrected Electronegativities and the Effect of Bond Polarity and Substituents on Covalent-Ionic Resonance Energy.

    Science.gov (United States)

    James, Andrew M; Laconsay, Croix J; Galbraith, John Morrison

    2017-07-13

    Bond dissociation energies and resonance energies for HnA-BHm molecules (A, B = H, C, N, O, F, Cl, Li, and Na) have been determined in order to re-evaluate the concept of electronegativity in the context of modern valence bond theory. Following Pauling's original scheme and using the rigorous definition of the covalent-ionic resonance energy provided by the breathing orbital valence bond method, we have derived a charge-shift corrected electronegativity scale for H, C, N, O, F, Cl, Li, and Na. Atomic charge shift character is defined using a similar approach resulting in values of 0.42, 1.06, 1.43, 1.62, 1.64, 1.44, 0.46, and 0.34 for H, C, N, O, F, Cl, Li, and Na, respectively. The charge-shift corrected electronegativity values presented herein follow the same general trends as Pauling's original values with the exception of Li having a smaller value than Na (1.57 and 1.91 for Li and Na respectively). The resonance energy is then broken down into components derived from the atomic charge shift character and polarization effects. It is then shown that most of the resonance energy in the charge-shift bonds H-F, H3C-F, and Li-CH3 and borderline charge-shift H-OH is associated with polarity rather than the intrinsic atomic charge-shift character of the bonding species. This suggests a rebranding of these bonds as "polar charge-shift" rather than simply "charge-shift". Lastly, using a similar breakdown method, it is shown that the small effect the substituents -CH3, -NH2, -OH, and -F have on the resonance energy (bonding atom.

  6. Energy transfer of surface wind-induced currents to the deep ocean via resonance with the Coriolis force

    Science.gov (United States)

    Ashkenazy, Yosef

    2017-03-01

    There are two main comparable sources of energy to the deep ocean-winds and tides. However, the identity of the most efficient mechanism that transfers wind energy to the deep ocean is still debated. Here we study, using oceanic general circulation model simulations and analytic derivations, the way that the wind directly supplies energy down to the bottom of the ocean when it is stochastic and temporally correlated or when it is periodic with a frequency that matches the Coriolis frequency. Basically, under these, commonly observed, conditions, one of the wind components resonates with the Coriolis frequency. Using reanalysis surface wind data and our simple model, we show that about one-third of the kinetic energy that is associated with wind-induced currents resides in the abyssal ocean, highlighting the importance of the resonance of the wind with the Coriolis force.

  7. Energy dispersion and relaxation in propynal using laser ir/visible double resonance

    Energy Technology Data Exchange (ETDEWEB)

    Lesiecki, M.L.; Smith, G.R.; Stewart, J.A.; Guillory, W.A.

    1979-01-01

    The dynamics of energy dispersion in propynal has been studied over the pressure range of 5 to 500 mtorr following excitation by a TEA CO/sub 2/ laser below the dissociation threshold. Wavelength resolved spectra, using the dye laser-induced fluorescence technique, are used to characterize the vibrational levels that are involved in the various energy transfer processes, while time-resolved spectra are used to determine the corresponding rates. The rate constants are extrapolated to zero pressure to obtain the regime of collisionless intramolecular relaxation time. Mechanisms of energy dispersion involving each of the probed vibrational levels (v = 0, ..nu../sub 6/(v = 1), ..nu../sub 9/(v = 1), and ..nu../sub 4/(v = 1)) are discussed.

  8. Home in the heat: Dramatic seasonal variation in home range of desert golden eagles informs management for renewable energy development

    Science.gov (United States)

    Braham, Melissa; Miller, Tricia A.; Duerr, Adam E.; Lanzone, Michael; Fesnock, Amy; LaPre, Larry; Driscoll, Daniel; Katzner, Todd E.

    2015-01-01

    Renewable energy is expanding quickly with sometimes dramatic impacts to species and ecosystems. To understand the degree to which sensitive species may be impacted by renewable energy projects, it is informative to know how much space individuals use and how that space may overlap with planned development. We used global positioning system–global system for mobile communications (GPS-GSM) telemetry to measure year-round movements of golden eagles (Aquila chrysaetos) from the Mojave Desert of California, USA. We estimated monthly space use with adaptive local convex hulls to identify the temporal and spatial scales at which eagles may encounter renewable energy projects in the Desert Renewable Energy Conservation Plan area. Mean size of home ranges was lowest and least variable from November through January and greatest in February–March and May–August. These monthly home range patterns coincided with seasonal variation in breeding ecology, habitat associations, and temperature. The expanded home ranges in hot summer months included movements to cooler, prey-dense, mountainous areas characterized by forest, grasslands, and scrublands. Breeding-season home ranges (October–May) included more lowland semi-desert and rock vegetation. Overlap of eagle home ranges and focus areas for renewable energy development was greatest when eagle home ranges were smallest, during the breeding season. Golden eagles in the Mojave Desert used more space and a wider range of habitat types than expected and renewable energy projects could affect a larger section of the regional population than was previously thought.

  9. Bi-resonant structure with piezoelectric PVDF films for energy harvesting from random vibration sources at low frequency

    DEFF Research Database (Denmark)

    Liang, Shanshan; Crovetto, Andrea; Peng, Zhuoteng

    2016-01-01

    and experiments with piezoelectric elements show that the energy harvesting device with the bi-resonant structure can generate higher power output than that of the sum of the two separate devices from random vibration sources at low frequency, and hence significantly improves the vibration-to- electricity...

  10. Visualization of polarized membrane type 1 matrix metalloproteinase activity in live cells by fluorescence resonance energy transfer imaging

    NARCIS (Netherlands)

    Ouyang, Mingxing; Lu, Shaoying; Li, Xiao-Yan; Xu, Jing; Seong, Jihye; Giepmans, Ben N. G.; Shyy, John Y. -J.; Weiss, Stephen J.; Wang, Yingxiao

    2008-01-01

    Membrane type 1 matrix metalloproteinase (MT1-MMP) plays a critical role in cancer cell biology by proteolytically remodeling the extracellular matrix. Utilizing fluorescence resonance energy transfer ( FRET) imaging, we have developed a novel biosensor, with its sensing element anchoring at the

  11. Förster resonance energy transfer demonstrates a flavonoid metabolon in living plant cells that displays competitive interactions between enzymes

    NARCIS (Netherlands)

    Crosby, K.C.; Pietraszewska-Bogiel, A.; Gadella (jr.), T.W.J.; Winkel, B.S.J.

    2011-01-01

    We have used Förster resonance energy transfer detected by fluorescence lifetime imaging microscopy (FLIM-FRET) to provide the first evidence from living plants cells for the existence of a flavonoid metabolon. The distribution of flux within this system may be regulated by the direct competition of

  12. Peptide-based fluorescence resonance energy transfer protease substrates for the detection and diagnosis of Bacillus species

    NARCIS (Netherlands)

    Kaman, W.E.; Hulst, A.G.; Alphen, P.T.W. van; Roffel, S.; Schans, M.J. van der; Merkel, T.; Belkum, A. van; Bikker, F.J.

    2011-01-01

    We describe the development of a highly specific enzyme-based fluorescence resonance energy transfer (FRET) assay for easy and rapid detection both in vitro and in vivo of Bacillus spp., among which are the members of the B. cereus group. Synthetic substrates for B. anthracis proteases were designed

  13. Development of homogeneous binding assays based on fluorescence resonance energy transfer between quantum dots and Alexa Fluor fluorophores.

    Science.gov (United States)

    Nikiforov, Theo T; Beechem, Joseph M

    2006-10-01

    We studied the fluorescence resonance energy transfer (FRET) between quantum dots emitting at 565, 605, and 655 nm as energy donors and Alexa Fluor fluorophores with absorbance maxima at 594, 633, 647, and 680 nm as energy acceptors. As a first step, we prepared covalent conjugates between all three types of quantum dots and each of the Alexa Fluor fluorophores that could act as an energy acceptor. All of these conjugates displayed efficient resonance energy transfer. Then we prepared covalent conjugates of these quantum dots with biotin, fluorescein, and cortisol and established that the binding of these conjugates to suitable Alexa Fluor-labeled antibodies and streptavidin (in the case of biotin) can be efficiently detected by measuring the resonance energy transfer in homogeneous solutions. Finally, based on these observations, competitive binding assays for these three small analytes were developed. The performance of these assays as a function of the degree of labeling of the quantum dots was evaluated. It was found that decreasing the degree of loading of the quantum dots leads to decreases of the limits of detection. The results show the great potential of this FRET system for the development of new homogeneous binding assays.

  14. Photofragmentation spectra of halogenated methanes in the VUV photon energy range

    Energy Technology Data Exchange (ETDEWEB)

    Cartoni, Antonella, E-mail: antonella.cartoni@uniroma1.it [Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, P.le Aldo Moro 5, Roma 00185 (Italy); Bolognesi, Paola; Fainelli, Ettore; Avaldi, Lorenzo [CNR-IMIP, Area della Ricerca di Roma 1, Monterotondo Scalo (Rm) 00015 (Italy)

    2014-05-14

    In this paper an investigation of the photofragmentation of dihalomethanes CH{sub 2}X{sub 2} (X = F, Cl, Br, I) and chlorinated methanes (CH{sub n}Cl{sub 4−n} with n = 0–3) with VUV helium, neon, and argon discharge lamps is reported and the role played by the different halogen atoms is discussed. Halogenated methanes are a class of molecules used in several fields of chemistry and the study of their physical and chemical proprieties is of fundamental interest. In particular their photodissociation and photoionization are of great importance since the decomposition of these compounds in the atmosphere strongly affects the environment. The results of the present work show that the halogen-loss is the predominant fragmentation channel for these molecules in the VUV photon energy range and confirm their role as reservoir of chlorine, bromine, and iodine atoms in the atmosphere. Moreover, the results highlight the peculiar feature of CH{sub 2}F{sub 2} as a source of both fluorine and hydrogen atoms and the characteristic formation of I{sub 2}{sup +} and CH{sub 2}{sup +} ions from the photofragmentation of the CH{sub 2}I{sub 2} molecule.

  15. Short-range order structure and effective pair-interaction energy in Ni-Si alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, Takumi [Department of Applied Physics, Graduate School of Engineering, Hokkaido University, Kita-ku, Sapporo 060-8628 (Japan); Hitachi, Ltd., Shinmachi Ome-shi, Tokyo 198-8512 (Japan); Osaka, Keiichi [Department of Applied Physics, Graduate School of Engineering, Hokkaido University, Kita-ku, Sapporo 060-8628 (Japan); Industrial Application Division, Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan)], E-mail: k-osaka@spring8.or.jp; Takama, Toshihiko [Department of Applied Physics, Graduate School of Engineering, Hokkaido University, Kita-ku, Sapporo 060-8628 (Japan); Chen, Haydn [Department of Physics and Materials Science, City University of Hong Kong, Kowloon, Hong Kong (China)

    2007-09-15

    The diffuse X-ray scattering from single crystals of Ni - 11.3 at.% Si and 12.3 at.% Si, both aged at 1293 K followed by a water quench, was measured at room temperature. The measured diffuse intensities were analyzed to determine the Warren-Cowley atomic short-range order (SRO) parameters {alpha}{sub lmn}. The 17 values of {alpha}{sub lmn} obtained were fitted in a 5 x 10{sup 5} atom model crystal to simulate the SRO. It was found that the C16 and the C17 configurations are significantly enhanced in comparison to a random crystal. The pair-interaction energies V{sub lmn} were obtained using an inverse Monte Carlo method from the {alpha}{sub lmn} parameters. Assuming that V{sub lmn} are independent of temperature, the {alpha}{sub lmn} were calculated as a function of temperature on the basis of the Monte Carlo simulation. The curves of {alpha}{sub lmn} for 11.3 at.% Si showed a knee point at 1262 (19) K and for 12.3 at.% Si at 1325 (11) K. Both temperatures are higher by about 100 K than those of the (fcc/fcc + L1{sub 2}) phase boundary in an equilibrium phase diagram.

  16. Early Detection of Trichinella spiralis in Muscle of Infected Mice by Real-Time Fluorescence Resonance Energy Transfer PCR

    Science.gov (United States)

    Tantrawatpan, Chairat; Intapan, Pewpan M.; Thanchomnang, Tongjit; Sanpool, Oranuch; Janwan, Penchom; Boonmars, Thidarut; Morakote, Nimit

    2013-01-01

    Abstract Real-time fluorescence resonance energy transfer (FRET) PCR and melting curve analysis using newly developed fluorophore-labeled hybridization probes were applied for the detection of Trichinella spiralis DNA in muscle of mice following oral inoculation with 300 T. spiralis larvae. The developed assay could detect and differentiate T. spiralis, Trichinella papuae, and Trichinella pseudospiralis DNAs by the different melting temperatures (Tm). The assay had a detection limit of 5×102 positive control plasmid copies, which was equivalent to 1 ng of T. spiralis DNA spiked into 250 mg of muscle sample. No fluorescence signal was detected when the technique was applied to the DNA of 27 parasites other than Trichinella spp. The assay could detect T. spiralis DNA in muscle at 7, 14, and 21 days postinoculation. The range, mean±standard deviation, and median of the Tm values of all positive muscle tissue samples were 60.4–60.8, 60.6±0.2, and 60.5, respectively. This assay provides an effective tool for the specific, sensitive, and high-throughput detection of T. spiralis DNA in muscle during the early stage of infection. In addition, the technique can be useful for epidemiologic surveillance in naturally infected wildlife. PMID:23808975

  17. Assessment of Gate Width Size on Lifetime-Based Förster Resonance Energy Transfer Parameter Estimation

    Directory of Open Access Journals (Sweden)

    Sez-Jade Chen

    2015-09-01

    Full Text Available Förster Resonance Energy Transfer (FRET enables the observation of interactions at the nanoscale level through the use of fluorescence optical imaging techniques. In FRET, fluorescence lifetime imaging can be used to quantify the fluorescence lifetime changes of the donor molecule, which are associated with proximity between acceptor and donor molecules. Among the FRET parameters derived from fluorescence lifetime imaging, the percentage of donor that interacts with the acceptor (in proximity can be estimated via model-based fitting. However, estimation of the lifetime parameters can be affected by the acquisition parameters such as the temporal characteristics of the imaging system. Herein, we investigate the effect of various gate widths on the accuracy of estimation of FRET parameters with focus on the near-infrared spectral window. Experiments were performed in silico, in vitro, and in vivo with gate width sizes ranging from 300 ps to 1000 ps in intervals of 100 ps. For all cases, the FRET parameters were retrieved accurately and the imaging acquisition time was decreased three-fold. These results indicate that increasing the gate width up to 1000 ps still allows for accurate quantification of FRET interactions even in the case of short lifetimes such as those encountered with near-infrared FRET pairs.

  18. Development of a Fluorescence Resonance Energy Transfer (FRET-Based DNA Biosensor for Detection of Synthetic Oligonucleotide of Ganoderma boninense

    Directory of Open Access Journals (Sweden)

    Noremylia Mohd Bakhori

    2013-12-01

    Full Text Available An optical DNA biosensor based on fluorescence resonance energy transfer (FRET utilizing synthesized quantum dot (QD has been developed for the detection of specific-sequence of DNA for Ganoderma boninense, an oil palm pathogen. Modified QD that contained carboxylic groups was conjugated with a single-stranded DNA probe (ssDNA via amide-linkage. Hybridization of the target DNA with conjugated QD-ssDNA and reporter probe labeled with Cy5 allows for the detection of related synthetic DNA sequence of Ganoderma boninense gene based on FRET signals. Detection of FRET emission before and after hybridization was confirmed through the capability of the system to produce FRET at 680 nm for hybridized sandwich with complementary target DNA. No FRET emission was observed for non-complementary system. Hybridization time, temperature and effect of different concentration of target DNA were studied in order to optimize the developed system. The developed biosensor has shown high sensitivity with detection limit of 3.55 × 10−9 M. TEM results show that the particle size of QD varies in the range between 5 to 8 nm after ligand modification and conjugation with ssDNA. This approach is capable of providing a simple, rapid and sensitive method for detection of related synthetic DNA sequence of Ganoderma boninense.

  19. Twenty-Eight Orders of Parametric Resonance in a Microelectromechanical Device for Multi-band Vibration Energy Harvesting

    Science.gov (United States)

    Jia, Yu; Du, Sijun; Seshia, Ashwin A.

    2016-01-01

    This paper contends to be the first to report the experimental observation of up to 28 orders of parametric resonance, which has thus far only been envisioned in the theoretical realm. While theory has long predicted the onset of n orders of parametric resonance, previously reported experimental observations have been limited up to about the first 5 orders. This is due to the rapid narrowing nature of the frequency bandwidth of the higher instability intervals, making practical accessibility increasingly more difficult. Here, the authors have experimentally confirmed up to 28 orders of parametric resonance in a micromachined membrane resonator when electrically undamped. While the implication of this finding spans across the vibration dynamics and transducer application spectrum, the particular significance of this work is to broaden the accumulative operational frequency bandwidth of vibration energy harvesting for enabling self-powered microsystems. Up to 5 orders were recorded when driven at 1.0 g of acceleration across a matched load of 70 kΩ. With a natural frequency of 980 Hz, the fundamental mode direct resonance had a −3 dB bandwidth of 55 Hz, in contrast to the 314 Hz for the first order parametric resonance; furthermore, the half power bands of all 5 orders accumulated to 478 Hz. PMID:27445205

  20. The 106Cd(alpha,alpha)106Cd elastic scattering in a wide energy range for gamma-process studies

    OpenAIRE

    Ornelas, A.; Kiss, G.G.(Institute for Nuclear Research (MTA ATOMKI), Debrecen, H-4001, Hungary); Mohr, P; Galaviz, D.; Fülöp, Zs.; Gyürky, Gy.(Institute for Nuclear Research (MTA ATOMKI), Debrecen, H-4001, Hungary); Máté, Z.; Rauscher, T.; Somorjai, E.; Sonnabend, K.; Zilges, A.

    2015-01-01

    Alpha elastic scattering angular distributions of the 106Cd(alpha,alpha)106Cd reaction were measured at three energies around the Coulomb barrier to provide a sensitive test for the alpha + nucleus optical potential parameter sets. Furthermore, the new high precision angular distributions, together with the data available from the literature were used to study the energy dependence of the locally optimized {\\alpha}+nucleus optical potential in a wide energy region ranging from E_Lab = 27.0 Me...

  1. Long-range protein electron transfer observed at the single-molecule level: In situ mapping of redox-gated tunneling resonance

    DEFF Research Database (Denmark)

    Chi, Qijin; Farver, O; Ulstrup, Jens

    2005-01-01

    on the redox potential. Maximum resonance appears around the equilibrium redox potential of azurin with an on/off current ratio of approximate to 9. Simulation analyses, based on a two-step interfacial ET model for the scanning tunneling microscopy redox process, were performed and provide quantitative......A biomimetic long-range electron transfer (ET) system consisting of the blue copper protein azurin, a tunneling barrier bridge, and a gold single-crystal electrode was designed on the basis of molecular wiring self-assembly principles. This system is sufficiently stable and sensitive in a quasi...

  2. Investigation of Prolactin Receptor Activation and Blockade Using Time-Resolved Fluorescence Resonance Energy Transfer

    Directory of Open Access Journals (Sweden)

    Estelle eTallet

    2011-09-01

    Full Text Available The prolactin receptor (PRLR is emerging as a therapeutic target in oncology. Knowledge-based drug design led to the development of a pure PRLR antagonist (Del1-9-G129R-hPRL that was recently shown to prevent PRL-induced mouse prostate tumorogenesis. In humans, the first gain-of-function mutation of the PRLR (PRLRI146L was recently identified in breast tumor patients. At the molecular level, the actual mechanism of action of these two novel players in the PRL system remains elusive. In this study, we addressed whether constitutive PRLR activation (PRLRI146L or PRLR blockade (antagonist involved alteration of receptor oligomerization and/or of inter-chain distances compared to unstimulated and PRL-stimulated PRLR. Using a combination of various biochemical and spectroscopic approaches (co-IP, blue-native electrophoresis, BRET1, we demonstrated that preformed PRLR homodimers are altered neither by PRL- or I146L-induced receptor triggering, nor by antagonist-mediated blockade. These findings were confirmed using a novel time-resolved fluorescence resonance energy transfer (TR-FRET technology that allows monitoring distance changes between cell-surface tagged receptors. This technology revealed that PRLR blockade or activation did not involve detectable distance changes between extracellular domains of receptor chains within the dimer. This study merges with our previous structural investigations suggesting that the mechanism of PRLR activation solely involves intermolecular contact adaptations leading to subtle intramolecular rearrangements.

  3. Detection of high energy cosmic rays with the resonant gravitational wave detector NAUTILUS and EXPLORER

    CERN Document Server

    Astone, P; Bassan, M; Bonifazi, P; Cavallari, G; Coccia, E; D'Antonio, S; Fafone, V; Giordano, G; Ligi, C; Marini, A; Mazzitelli, G; Minenkov, Y; Modena, I; Modestino, G; Moleti, A; Pallottino, G V; Pizzella, G; Quintieri, L; Rocchi, A; Ronga, F; Terenzi, R; Visco, M

    2008-01-01

    The cryogenic resonant gravitational wave detectors NAUTILUS and EXPLORER, made of an aluminum alloy bar, can detect cosmic ray showers. At temperatures above 1 K, when the material is in the normal conducting state, the measured signals are in good agreement with the values expected based on the cosmic rays data and on the thermo-acoustic model. When NAUTILUS was operated at the temperature of 0.14 K, in superconductive state, large signals produced by cosmic ray interactions, more energetic than expected, were recorded. The NAUTILUS data in this case are in agreement with the measurements done by a dedicated experiment on a particle beam. The biggest recorded event was in EXPLORER and excited the first longitudinal mode to a vibrational energy of about K, corresponding to about 360 TeV absorbed in the bar. Cosmic rays can be an important background in future acoustic detectors of improved sensitivity. At present, they represent a useful tool to verify the gravitational wave antenna performance.

  4. Photonic effects on the Förster resonance energy transfer efficiency.

    Science.gov (United States)

    Rabouw, Freddy T; den Hartog, Stephan A; Senden, Tim; Meijerink, Andries

    2014-04-02

    Förster resonance energy transfer (ET) between luminescent species is applied in bio-imaging, lighting and photovoltaics, and has an important role in photosynthesis. However, the fundamental question of whether ET rates and efficiencies can be tuned by the photonic environment remains under debate. Here we show that ET rates are independent of the photonic environment, using the model system of LaPO4 nanocrystals co-doped with Ce(3+) donors and Tb(3+) acceptors. Although the radiative emission rate of the Ce(3+) excited state increases with the refractive index of the solvent in which the nanocrystals are dispersed, the Ce(3+)-to-Tb(3+) ET rate does not. We demonstrate that, as a result, lower refractive index solvents enable higher ET efficiencies leading to higher Tb(3+) emission intensities. Furthermore, an analytical model for ET in (nano)crystalline host materials is presented, able to predict the dependence of ET efficiencies on the photonic environment and the concentration of acceptor ions.

  5. Photonic effects on the Förster resonance energy transfer efficiency

    Science.gov (United States)

    Rabouw, Freddy T.; den Hartog, Stephan A.; Senden, Tim; Meijerink, Andries

    2014-04-01

    Förster resonance energy transfer (ET) between luminescent species is applied in bio-imaging, lighting and photovoltaics, and has an important role in photosynthesis. However, the fundamental question of whether ET rates and efficiencies can be tuned by the photonic environment remains under debate. Here we show that ET rates are independent of the photonic environment, using the model system of LaPO4 nanocrystals co-doped with Ce3+ donors and Tb3+ acceptors. Although the radiative emission rate of the Ce3+ excited state increases with the refractive index of the solvent in which the nanocrystals are dispersed, the Ce3+-to-Tb3+ ET rate does not. We demonstrate that, as a result, lower refractive index solvents enable higher ET efficiencies leading to higher Tb3+ emission intensities. Furthermore, an analytical model for ET in (nano)crystalline host materials is presented, able to predict the dependence of ET efficiencies on the photonic environment and the concentration of acceptor ions.

  6. A double epitope tag for quantification of recombinant protein using fluorescence resonance energy transfer.

    Science.gov (United States)

    Enomoto, Koji; Uwabe, Ken-Ichiro; Naito, Shoichi; Onoda, Jyunji; Yamauchi, Akira; Numata, Yoshito; Takemoto, Hiroshi

    2008-09-15

    The expression of recombinant proteins is a well-accepted technology, but their detection and purification often require time-consuming and complicated processes. This paper describes the development of a novel double epitope tag (GEPGDDGPSGAEGPPGPQG) for rapid and accurate quantification of recombinant protein by a homogeneous immunoassay based on fluorescence resonance energy transfer. In our double epitope tagging system, recombinant proteins can be simply measured on a microtiter plate by addition of a pair of fluorophore-labeled monoclonal antibodies (their epitopes; GEPGDDGPS and GPPGPQG). The sensitivity of the immunoassay with an incubation time of only 5 min is almost equal to that of labor-intensive Western blotting. In addition, culture media and extracts of host cells generally used for protein expression have little effect on this immunoassay. To investigate the utility of our proposed tag for protein production, several different proteins containing this tag were practically expressed and purified. The data presented demonstrate that the double epitope tag is a reliable tool that can alleviate the laborious and troublesome processes of protein production.

  7. Detection of Citrus tristeza virus by using fluorescence resonance energy transfer-based biosensor

    Science.gov (United States)

    Shojaei, Taha Roodbar; Salleh, Mohamad Amran Mohd; Sijam, Kamaruzaman; Rahim, Raha Abdul; Mohsenifar, Afshin; Safarnejad, Reza; Tabatabaei, Meisam

    2016-12-01

    Due to the low titer or uneven distribution of Citrus tristeza virus (CTV) in field samples, detection of CTV by using conventional detection techniques may be difficult. Therefore, in the present work, the cadmium-telluride quantum dots (QDs) was conjugated with a specific antibody against coat protein (CP) of CTV, and the CP were immobilized on the surface of gold nanoparticles (AuNPs) to develop a specific and sensitive fluorescence resonance energy transfer (FRET)-based nanobiosensor for detecting CTV. The maximum FRET efficiency for the developed nano-biosensor was observed at 60% in AuNPs-CP/QDs-Ab ratio of 1:8.5. The designed system showed higher sensitivity and specificity over enzyme linked immunosorbent assay (ELISA) with a limit of detection of 0.13 μg mL- 1 and 93% and 94% sensitivity and specificity, respectively. As designed sensor is rapid, sensitive, specific and efficient in detecting CTV, this could be envisioned for diagnostic applications, surveillance and plant certification program.

  8. Thrombin detection in murine plasma using engineered fluorescence resonance energy transfer aptadimers

    Science.gov (United States)

    Trapaidze, Ana; Brut, Marie; Mazères, Serge; Estève, Daniel; Gué, Anne-Marie; Bancaud, Aurélien

    2015-12-01

    Biodetection strategies, in which two sides of one target protein are targeted simultaneously, have been shown to increase specificity, selectivity, and affinity, and it has been suggested that they constitute excellent candidates for protein sensing in complex media. In this study we propose a method to engineer the sequence of a DNA construct dedicated to reversible thrombin detection. This construct, called Fluorescence Resonance Energy Transfer (FRET) aptadimer, is assembled with two aptamers, which target different epitopes of thrombin, interconnected with a DNA linker that contains a FRET couple and a reversible double helix stem. In the absence of target, the stem is stable maintaining a FRET couple in close proximity, and fluorescence is unquenched upon thrombin addition due to the dehybridization of the stem. We define design rules for the conception of FRET aptadimers, and develop a software to optimize their functionality. One engineered FRET aptadimer sequence is subsequently characterized experimentally by temperature scanning fluorimetry, demonstrating the relevance of our technology for thrombin sensing in bulk and diluted murine plasma.

  9. Single-molecule-sensitive fluorescence resonance energy transfer in freely-diffusing attoliter droplets

    Energy Technology Data Exchange (ETDEWEB)

    Rahmanseresht, Sheema; Ramos, Kieran P.; Gamari, Ben D.; Goldner, Lori S., E-mail: lgoldner@physics.umass.edu [Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003 (United States); Milas, Peker [Department of Neuroscience, University of Wisconsin, Madison, Wisconsin 53705 (United States)

    2015-05-11

    Fluorescence resonance energy transfer (FRET) from individual, dye-labeled RNA molecules confined in freely-diffusing attoliter-volume aqueous droplets is carefully compared to FRET from unconfined RNA in solution. The use of freely-diffusing droplets is a remarkably simple and high-throughput technique that facilitates a substantial increase in signal-to-noise for single-molecular-pair FRET measurements. We show that there can be dramatic differences between FRET in solution and in droplets, which we attribute primarily to an altered pH in the confining environment. We also demonstrate that a sufficient concentration of a non-ionic surfactant mitigates this effect and restores FRET to its neutral-pH solution value. At low surfactant levels, even accounting for pH, we observe differences between the distribution of FRET values in solution and in droplets which remain unexplained. Our results will facilitate the use of nanoemulsion droplets as attoliter volume reactors for use in biophysical and biochemical assays, and also in applications such as protein crystallization or nanoparticle synthesis, where careful attention to the pH of the confined phase is required.

  10. Fluorescence Resonance Energy Transfer Assay for High-Throughput Screening of ADAMTS1 Inhibitors

    Directory of Open Access Journals (Sweden)

    Guanhua Du

    2011-12-01

    Full Text Available A disintegrin and metalloprotease with thrombospondin type I motifs-1 (ADAMTS1 plays a crucial role in inflammatory joint diseases and its inhibitors are potential candidates for anti-arthritis drugs. For the purposes of drug discovery, we reported the development and validation of fluorescence resonance energy transfer (FRET assay for high-throughput screening (HTS of the ADAMTS1 inhibitors. A FRET substrate was designed for a quantitative assay of ADAMTS1 activity and enzyme kinetics studies. The assay was developed into a 50-µL, 384-well assay format for high throughput screening of ADAMTS1 inhibitors with an overall Z’ factor of 0.89. ADAMTS1 inhibitors were screened against a diverse library of 40,960 total compounds with the established HTS system. Four structurally related hits, naturally occurring compounds, kuwanon P, kuwanon X, albafuran C and mulberrofuran J, extracted from the Chinese herb Morus alba L., were identified for further investigation. The results suggest that this FRET assay is an excellent tool, not only for measurement of ADAMTS1 activity but also for discovery of novel ADAMTS1 inhibitors with HTS.

  11. Semiconductor quantum dots as Förster resonance energy transfer donors for intracellularly-based biosensors

    Science.gov (United States)

    Field, Lauren D.; Walper, Scott A.; Susumu, Kimihiro; Oh, Eunkeu; Medintz, Igor L.; Delehanty, James B.

    2017-02-01

    Förster resonance energy transfer (FRET)-based assemblies currently comprise a significant portion of intracellularly based sensors. Although extremely useful, the fluorescent protein pairs typically utilized in such sensors are still plagued by many photophysical issues including significant direct acceptor excitation, small changes in FRET efficiency, and limited photostability. Luminescent semiconductor nanocrystals or quantum dots (QDs) are characterized by many unique optical properties including size-tunable photoluminescence, broad excitation profiles coupled to narrow emission profiles, and resistance to photobleaching, which can cumulatively overcome many of the issues associated with use of fluorescent protein FRET donors. Utilizing QDs for intracellular FRET-based sensing still requires significant development in many areas including materials optimization, bioconjugation, cellular delivery and assay design and implementation. We are currently developing several QD-based FRET sensors for various intracellular applications. These include sensors targeting intracellular proteolytic activity along with those based on theranostic nanodevices for monitoring drug release. The protease sensor is based on a unique design where an intracellularly expressed fluorescent acceptor protein substrate assembles onto a QD donor following microinjection, forming an active complex that can be monitored in live cells over time. In the theranostic configuration, the QD is conjugated to a carrier protein-drug analogue complex to visualize real-time intracellular release of the drug from its carrier in response to an external stimulus. The focus of this talk will be on the design, properties, photophysical characterization and cellular application of these sensor constructs.

  12. Quantum dots-fluorescence resonance energy transfer-based nanosensors and their application.

    Science.gov (United States)

    Stanisavljevic, Maja; Krizkova, Sona; Vaculovicova, Marketa; Kizek, Rene; Adam, Vojtech

    2015-12-15

    Fluorescence resonance energy transfer (FRET) in combination with quantum dots (QDs) and their superior properties has enabled designing of the new and improved sensors. In this review, the latest novelties in development and application of FRET nanosensors employing QDs are presented. QDs offer several advantages over organic dyes - broad excitation spectra, narrow defined tunable emission peak, longer fluorescence lifetime, resistance to photobleaching and 10-100 times higher molar extinction coefficient. These properties of QDs allow multicolor QDs to be excited from one source by common fluorescent dyes without emission signal overlap and results in brighter probes comparing to conventional fluorophores. Due to these benefits, QD-FRET-based nanosensors gained a wide spread popularity in a variety of scientific areas. These sensors are most frequently applied in the domain of the nucleic acid and enzyme activity detection. Other applications are detection of peptides and low-molecular compounds, environmental pollutants, viruses, microorganisms and their toxins, QD-FRET-based immunoassays, and pH sensors. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Effect of enhanced Renilla luciferase and fluorescent protein variants on the Foerster distance of Bioluminescence resonance energy transfer (BRET)

    Energy Technology Data Exchange (ETDEWEB)

    Dacres, Helen, E-mail: helen.dacres@csiro.au [CSIRO Food Futures Flagship and Ecosystem Sciences, Canberra (Australia); Michie, Michelle; Wang, Jian [CSIRO Food Futures Flagship and Ecosystem Sciences, Canberra (Australia); Pfleger, Kevin D.G. [Laboratory for Molecular Endocrinology-GPCRs, Western Australian Institute for Medical Research (WAIMR) and Centre for Medical Research, The University of Western Australia, Perth (Australia); Trowell, Stephen C. [CSIRO Food Futures Flagship and Ecosystem Sciences, Canberra (Australia)

    2012-08-31

    Highlights: Black-Right-Pointing-Pointer First experimental determination of Foerster distance (R{sub 0}) for enhanced BRET systems. Black-Right-Pointing-Pointer Effect of brighter BRET components RLuc2, RLuc8 and Venus was assessed. Black-Right-Pointing-Pointer Using brighter BRET components substantially increased (25%) R{sub 0} of the BRET{sup 1} system. Black-Right-Pointing-Pointer Using brighter BRET components marginally increased (2-9%) R{sub 0} of the BRET{sup 2} system. Black-Right-Pointing-Pointer Brighter BRET components improve the different weaknesses of BRET{sup 1} and BRET{sup 2} systems. -- Abstract: Bioluminescence resonance energy transfer (BRET) is an important tool for monitoring macromolecular interactions and is useful as a transduction technique for biosensor development. Foerster distance (R{sub 0}), the intermolecular separation characterized by 50% of the maximum possible energy transfer, is a critical BRET parameter. R{sub 0} provides a means of linking measured changes in BRET ratio to a physical dimension scale and allows estimation of the range of distances that can be measured by any donor-acceptor pair. The sensitivity of BRET assays has recently been improved by introduction of new BRET components, RLuc2, RLuc8 and Venus with improved quantum yields, stability and brightness. We determined R{sub 0} for BRET{sup 1} systems incorporating novel RLuc variants RLuc2 or RLuc8, in combination with Venus, as 5.68 or 5.55 nm respectively. These values were approximately 25% higher than the R{sub 0} of the original BRET{sup 1} system. R{sub 0} for BRET{sup 2} systems combining green fluorescent proteins (GFP{sup 2}) with RLuc2 or RLuc8 variants was 7.67 or 8.15 nm, i.e. only 2-9% greater than the original BRET{sup 2} system despite being {approx}30-fold brighter.

  14. WATER SPOTTERS: Water, energy, isotopes and experiential learning in the Colorado Front Range

    Science.gov (United States)

    Noone, D. C.; Berkelhammer, M. B.; Raudzens Bailey, A.; Buhr, S. M.; Smith, L. K.

    2011-12-01

    Providing students with tangible examples of the two-way interaction between human society and the climate system is a pressing challenge. Water is at the core of many issues in environmental change from local to global scales. In climate research, there are significant uncertainties in the role water plays in the climate system. "Water" can also act as a central theme that provides opportunities for science education at all levels. WATER SPOTTERS takes advantage of the prominent agricultural landscape of the region, which is a poignant example of how society influences the climate through irrigation, evaporation/transpiration and run-off and whose productivity is influenced by the climate system. Both natural grasslands and alpine ecosystems in the surrounding regions serve as examples of the native landscape. The centerpiece of this project is a 300m tower that is fully implemented with gas sampling lines and micrometeorological equipment to study the energy and water budgets of the region. Middle Schools that surround this site, many of which exist in visual contact with the tall tower, are provided with meteorological stations, which provide rainfall rates, temperature, humidity and radiation data. In coordination with the St Vrain Valley School District MESA (Math Engineering Science Achievement) program, students collect rain water samples that are analyzed and used as a core component of the research goals. The students use the weather stations as a way to directly explore their local climatology and provide data that is needed in research. We present an overview of the curriculum goals and associated physical infrastructure designed for middle school students in the Colorado Front Range to explore their local water cycle using water isotopes. The fixed infrastructure at the schools and tall tower are supplemented by mobile instruments such as an automated precipitation collector and snowflake photography system, which both fulfill science needs and provide

  15. Investigation of multilayer X-ray optics for the 6 keV to 20 keV energy range.

    Science.gov (United States)

    Oberta, P; Platonov, Y; Flechsig, U

    2012-09-01

    The X-ray optics group at the Swiss Light Source in co-operation with RIT (Rigaku Innovative Technologies) have investigated seven different multilayer samples. The goal was to find an ideal multilayer structure for the energy range between 6 keV and 20 keV in terms of energy resolution and reflectivity. Such multilayer structures deposited on substrates can be used as X-ray monochromators or reflecting synchrotron mirrors. The measured reflectivities agree with the simulated ones. They cover a reflectivity range from 45% to 80% for energies between 6 keV and 10 keV, and 80% to 90% for energies between 10 keV and 20 keV. The experimentally measured energy resolution of the samples lies between 0.3% and 3.5%.

  16. Complete polarization analysis in the 1keV to 2keV energy range using a high-precision polarimeter

    Science.gov (United States)

    Wang, Hongchang; Dhesi, Sarnjeet; Bencok, Peter; Steadman, Paul; Maccherozzi, Francesco; Sawhney, Kawal

    2013-03-01

    The Beryl and YB66 crystals are proved to be suitable as analyzers in the energy range from 1.0keV to 2.0keV. The s-component reflectivity (Rs) of Beryl crystal reaches up to 10% with polarizing power Rs/Rp over 1000 at 1.1keV. The free-standing W/B4C multilayer has the phase shift over 5° with moderate transmission up to 1.7keV. The Bragg resonance width of the Beryl crystal is only 350 microradians at 1.1keV, and the incidence angle of the beam onto the crystal needs to be constant within 50 microradians or better. A high-precision polarimeter was used for the polarimetry experiment, and the complete polarization analysis of the APPLE II undulator at 1.1 keV and 1.56keV will be presented.

  17. Construction of Multichromophoric Spectra from Monomer Data: Applications to Resonant Energy Transfer.

    Science.gov (United States)

    Chenu, Aurélia; Cao, Jianshu

    2017-01-06

    We develop a model that establishes a quantitative link between the physical properties of molecular aggregates and their constituent building blocks. The relation is built on the coherent potential approximation, calibrated against exact results, and proven reliable for a wide range of parameters. It provides a practical method to compute spectra and transfer rates in multichromophoric systems from experimentally accessible monomer data. Applications to Förster energy transfer reveal optimal transfer rates as functions of both the system-bath coupling and intra-aggregate coherence.

  18. Analysis of Long-range Clean Energy Investment Scenarios forEritrea, East Africa

    Energy Technology Data Exchange (ETDEWEB)

    Van Buskirk, Robert D.

    2004-05-07

    We discuss energy efficiency and renewable energy investments in Eritrea from the strategic long-term economic perspective of meeting Eritrea's sustainable development goals and reducing greenhouse gas emissions. Energy efficiency and renewable energy are potentially important contributors to national productive capital accumulation, enhancement of the environment, expansion of energy services, increases in household standard of living, and improvements in health. In this study we develop a spreadsheet model for calculating some of the national benefits and costs of different levels of investment in energy efficiency and renewable energy. We then present the results of the model in terms of investment demand and investment scenario curves. These curves express the contribution that efficiency and renewable energy projects can make in terms of reduced energy sector operating expenses, and reduced carbon emissions. We provide demand and supply curves that show the rate of return, the cost of carbon emissions reductions vs. supply, and the evolution of the marginal carbon emissions per dollar of GDP for different investment levels and different fuel-type subsectors.

  19. Enhancement of Energy Harvesting Performance by a Coupled Bluff Splitter Body and PVEH Plate through Vortex Induced Vibration near Resonance

    Directory of Open Access Journals (Sweden)

    Wei Ken Chin

    2017-09-01

    Full Text Available Inspired by vortex induced vibration energy harvesting development as a new source of renewable energy, a T-shaped design vibration energy harvester is introduced with the aim of enhancing its performance through vortex induced vibration at near resonance conditions. The T-shaped structural model designed consists of a fixed boundary aluminum bluff splitter body coupled with a cantilever piezoelectric vibration energy harvesters (PVEH plate model which is a piezoelectric bimorph plate made of a brass plate sandwiched between 2 lead zirconate titanate (PZT plates. A 3-dimensional Fluid-Structure Interaction simulation analysis is carried out with Reynolds Stress Turbulence Model under wind speed of 7, 10, 12, 14, 16, 18, 19, 20, 22.5, and 25 m/s. The results showed that with 19 m/s wind speed, the model generates 75.758 Hz of vortex frequency near to the structural model’s natural frequency of 76.9 Hz. Resonance lock-in therefore occurred, generating a maximum displacement amplitude of 2.09 mm or a 49.76% increment relatively in vibrational amplitude. Under the effect of resonance at the PVEH plate’s fundamental natural frequency, it is able to generate the largest normalized power of 13.44 mW/cm3g2.

  20. Preliminary Performance Evaluation of MEMS-based Piezoelectric Energy Harvesters in Extended Temperature Range

    DEFF Research Database (Denmark)

    Xu, R.; Borregaard, L.M.; Lei, A.

    2012-01-01

    In this work a batch of MEMS-based vibration energy harvesters consisting of a silicon/PZT thick film ntilever with integrated proof mass is characterized. The purpose of a vibration energy harvester is to convert low grade vibrations to useful electrical power. Optimally, the natural frequency o...

  1. A simple and selective resonance Rayleigh scattering-energy transfer spectral method for determination of trace neomycin sulfate using Cu2O particle as probe

    Science.gov (United States)

    Ouyang, Huixiang; Liang, Aihui; Jiang, Zhiliang

    2018-02-01

    The stable Cu2O nanocubic (Cu2ONC) sol was prepared, based on graphene oxide (GO) catalysis of glucose-Fehling's reagent reaction, and its absorption and resonance Rayleigh scattering (RRS) spectra, transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) were examined. Using the as-prepared Cu2ONC as RRS probe, and coupling with the neomycin sulfate (NEO) complex reaction, a new, simple, sensitive and selective RRS-energy transfer (RRS-ET) method was established for detection of neomycin sulfate, with a linear range of 1.4-112 μM and a detection limit of 0.4 μM. The method has been applied to the detection of neomycin sulfate in samples with satisfactory results.

  2. Andromede project: Surface analysis and modification with probes from hydrogen to nano-particles in the MeV energy range

    Energy Technology Data Exchange (ETDEWEB)

    Eller, Michael J.; Cottereau, Evelyne [Institut de Physique Nucléaire d’Orsay, UMR8608, CNRS/IN2P3, Université Paris-Sud 11, F-91406 Orsay (France); Rasser, Bernard; Verzeroli, Elodie [Orsay Physics, ZAC Saint Charles, 95 Av des Monts Auréliens, 13710 Fuveau (France); Agnus, Benoit; Gaubert, Gabriel; Donzel, Xavier [Pantechnik SA, 13 rue de la Résistance, 14400 Bayeux (France); Delobbe, Anne [Orsay Physics, ZAC Saint Charles, 95 Av des Monts Auréliens, 13710 Fuveau (France); Della-Negra, Serge, E-mail: dellaneg@ipno.in2p3.fr [Institut de Physique Nucléaire d’Orsay, UMR8608, CNRS/IN2P3, Université Paris-Sud 11, F-91406 Orsay (France)

    2015-12-15

    The Andromede project is the center of a multi-disciplinary team which will build a new instrument for surface modification and analysis using the impact of probes from hydrogen to nano-particles (Au{sub 400}{sup +4}) in the MeV range. For this new instrument a series of atomic, polyatomic, molecular and nano-particle ion beams will be delivered using two ion sources in tandem, a liquid metal ion source and an electron cyclotron resonance source. The delivered ion beams will be accelerated to high energy with a 4 MeV van de Graaff type accelerator. By using a suite of probes in the MeV energy range, ion beam analysis techniques, MeV atomic and cluster secondary ion mass spectrometry can all be performed in one location. A key feature of the instrument is its ability to produce an intense beam for injection into the accelerator. The commissioning of the two sources shows that intense beams from atomic ions to nano-particles can be delivered for subsequent acceleration. The calculations and measurements for the two sources are presented.

  3. Investigation of single event upset subject to protons of intermediate energy range

    Energy Technology Data Exchange (ETDEWEB)

    Takami, Y.; Shiraishi, F. (Rikkyo Univ., Yokosuka, Kanagawa (Japan). Inst. for Atomic Energy); Goka, T.; Shimano, Y. (Tsukuba Space Center, NASDA, 2-1-1, Sengen, Tsukuba, Ibaragi 305 (JP)); Sekiguchi, M.; Shida, K. (Inst. for Nuclear Energy, Univ. of Tokyo, 3-2-1 Midoricho, Tanashi, Tokyo 188 (JP)); Kishida, N.; Kadotani, H. (Century Research Center Corp., Tokyo (Japan)); Kikuchi, T. (NEC Corp., 4035 Ikebecho, Midoriku, Yokohama, Kanagawa 226 (JP)); Hoshino, N. (Toshiba Corp., Kawasaki (Japan)); Murakami, S. (Fujitsu Labs. Ltd., Kawasaki, Kanagawa (Japan)); Anayama, H.; Morio, A. (Reliability Center for Electonic Components of Japan, 3-4-13 Nihonbashi, Chuoku, Tokyo 103 (JP))

    1990-12-01

    Nuclear reaction models to reproduce p + Si nuclear reactions precisely in the incident proton energy region of below 50 MeV were investigated, and a computer code based on exciton models was developed. Si irradiation experiments in the intermediate energy region were performed to measure energy deposit by p + Si nuclear reactions, with two totally depleted Si detectors in face-to-face arrangement. Coincident signals were analyzed by a two dimensional pulse height analyzer. This method is shown to be effective in discriminating signals of contaminating particles.

  4. Personal dose equivalent conversion coefficients for neutron fluence over the energy range of 20-250 MeV.

    Science.gov (United States)

    Olsher, R H; McLean, T D; Justus, A L; Devine, R T; Gadd, M S

    2010-03-01

    Monte Carlo simulations were performed to extend existing neutron personal dose equivalent fluence-to-dose conversion coefficients to an energy of 250 MeV. Presently, conversion coefficients, H(p,slab)(10,alpha)/Phi, are given by ICRP-74 and ICRU-57 for a range of angles of radiation incidence (alpha = 0, 15, 30, 45, 60 and 75 degrees ) in the energy range from thermal to 20 MeV. Standard practice has been to base operational dose quantity calculations 20 MeV. Both light and heavy ions (HIs) (carbon, nitrogen and oxygen recoil nuclei) were transported down to a lower energy limit (1 keV for light ions and 5 MeV for HIs). Track energy below the limit was assumed to be locally deposited. For neutron tracks slab phantom.

  5. Investigation of Membrane Receptors' Oligomers Using Fluorescence Resonance Energy Transfer and Multiphoton Microscopy in Living Cells

    Science.gov (United States)

    Mishra, Ashish K.

    Investigating quaternary structure (oligomerization) of macromolecules (such as proteins and nucleic acids) in living systems (in vivo) has been a great challenge in biophysics, due to molecular diffusion, fluctuations in several biochemical parameters such as pH, quenching of fluorescence by oxygen (when fluorescence methods are used), etc. We studied oligomerization of membrane receptors in living cells by means of Fluorescence (Forster) Resonance Energy Transfer (FRET) using fluorescent markers and two photon excitation fluorescence micro-spectroscopy. Using suitable FRET models, we determined the stoichiometry and quaternary structure of various macromolecular complexes. The proteins of interest for this work are : (1) sigma-1 receptor and (2) rhodopsin, are described as below. (1) Sigma-1 receptors are molecular chaperone proteins, which also regulate ion channels. S1R seems to be involved in substance abuse, as well as several diseases such as Alzheimer's. We studied S1R in the presence and absence of its ligands haloperidol (an antagonist) and pentazocine +/- (an agonist), and found that at low concentration they reside as a mixture of monomers and dimers and that they may form higher order oligomers at higher concentrations. (2) Rhodopsin is a prototypical G protein coupled receptor (GPCR) and is directly involved in vision. GPCRs form a large family of receptors that participate in cell signaling by responding to external stimuli such as drugs, thus being a major drug target (more than 40% drugs target GPCRs). Their oligomerization has been largely controversial. Understanding this may help to understand the functional role of GPCRs oligomerization, and may lead to the discovery of more drugs targeting GPCR oligomers. It may also contribute toward finding a cure for Retinitis Pigmentosa, which is caused by a mutation (G188R) in rhodopsin, a disease which causes blindness and has no cure so far. Comparing healthy rhodopsin's oligomeric structure with that

  6. Linear approaches to intramolecular Förster resonance energy transfer probe measurements for quantitative modeling.

    Directory of Open Access Journals (Sweden)

    Marc R Birtwistle

    Full Text Available Numerous unimolecular, genetically-encoded Förster Resonance Energy Transfer (FRET probes for monitoring biochemical activities in live cells have been developed over the past decade. As these probes allow for collection of high frequency, spatially resolved data on signaling events in live cells and tissues, they are an attractive technology for obtaining data to develop quantitative, mathematical models of spatiotemporal signaling dynamics. However, to be useful for such purposes the observed FRET from such probes should be related to a biological quantity of interest through a defined mathematical relationship, which is straightforward when this relationship is linear, and can be difficult otherwise. First, we show that only in rare circumstances is the observed FRET linearly proportional to a biochemical activity. Therefore in most cases FRET measurements should only be compared either to explicitly modeled probes or to concentrations of products of the biochemical activity, but not to activities themselves. Importantly, we find that FRET measured by standard intensity-based, ratiometric methods is inherently non-linear with respect to the fraction of probes undergoing FRET. Alternatively, we find that quantifying FRET either via (1 fluorescence lifetime imaging (FLIM or (2 ratiometric methods where the donor emission intensity is divided by the directly-excited acceptor emission intensity (denoted R(alt is linear with respect to the fraction of probes undergoing FRET. This linearity property allows one to calculate the fraction of active probes based on the FRET measurement. Thus, our results suggest that either FLIM or ratiometric methods based on R(alt are the preferred techniques for obtaining quantitative data from FRET probe experiments for mathematical modeling purposes.

  7. Real-Time Detection of Cellular Death Receptor-4 Activation by Fluorescence Resonance Energy Transfer

    Science.gov (United States)

    Dereli-Korkut, Zeynep; Gandhok, Harmeet; Zeng, Ling Ge; Waqas, Sidra; Jiang, Xuejun; Wang, Sihong

    2017-01-01

    Targeted therapy involving the activation of death receptors DR4 and/or DR5 by its ligand, TRAIL, can selectively induce apoptosis in certain tumor cells. In order to profile the dynamic activation or trimerization of TRAIL-DR4 in live cells in real time, the development of an apoptosis reporter cell line is essential. Fluorescence resonance energy transfer (FRET) technology via a FRET pair, cyan fluorescence protein (CFP) and yellow fluorescence protein (YFP), was used in this study. DR4-CFP and DR4-YFP were stably expressed in human lung cancer PC9 cells. Flow cytometer sorting and limited dilution coupled with fluorescence microscopy were used to select a monoclonal reporter cell line with high and compatible expression levels of DR4-CFP and DR4-YFP. FRET experiments were conducted and FRET efficiencies were monitored according to the Siegel’s YFP photobleaching FRET protocol. Upon TRAIL induction a significant increase in FRET efficiencies from 5 to 9% demonstrated the ability of the DR4-CFP/YFP reporter cell line in monitoring the dynamic activation of TRAIL pathways. 3D reconstructed confocal images of DR4-CFP/YFP reporter cells exhibited a colocalized expression of DR4-CFP and DR4-YFP mainly on cell membranes. FRET results obtained during this study complements the use of epi-fluorescence microscopy for FRET analysis. The real-time FRET analysis allows the dynamic profiling of the activation of TRAIL pathways by using the time-lapse fluorescence microscopy. Therefore, DR4-CFP/YFP PC9 reporter cells along with FRET technology can be used as a tool for anti-cancer drug screening to identify compounds that are capable of activating TRAIL pathways. PMID:23239419

  8. Image Processing for Bioluminescence Resonance Energy Transfer Measurement-BRET-Analyzer.

    Science.gov (United States)

    Chastagnier, Yan; Moutin, Enora; Hemonnot, Anne-Laure; Perroy, Julie

    2017-01-01

    A growing number of tools now allow live recordings of various signaling pathways and protein-protein interaction dynamics in time and space by ratiometric measurements, such as Bioluminescence Resonance Energy Transfer (BRET) Imaging. Accurate and reproducible analysis of ratiometric measurements has thus become mandatory to interpret quantitative imaging. In order to fulfill this necessity, we have developed an open source toolset for Fiji-BRET-Analyzer-allowing a systematic analysis, from image processing to ratio quantification. We share this open source solution and a step-by-step tutorial at https://github.com/ychastagnier/BRET-Analyzer. This toolset proposes (1) image background subtraction, (2) image alignment over time, (3) a composite thresholding method of the image used as the denominator of the ratio to refine the precise limits of the sample, (4) pixel by pixel division of the images and efficient distribution of the ratio intensity on a pseudocolor scale, and (5) quantification of the ratio mean intensity and standard variation among pixels in chosen areas. In addition to systematize the analysis process, we show that the BRET-Analyzer allows proper reconstitution and quantification of the ratiometric image in time and space, even from heterogeneous subcellular volumes. Indeed, analyzing twice the same images, we demonstrate that compared to standard analysis BRET-Analyzer precisely define the luminescent specimen limits, enlightening proficient strengths from small and big ensembles over time. For example, we followed and quantified, in live, scaffold proteins interaction dynamics in neuronal sub-cellular compartments including dendritic spines, for half an hour. In conclusion, BRET-Analyzer provides a complete, versatile and efficient toolset for automated reproducible and meaningful image ratio analysis.

  9. Combining MFD and PIE for accurate single-pair Förster resonance energy transfer measurements.

    Science.gov (United States)

    Kudryavtsev, Volodymyr; Sikor, Martin; Kalinin, Stanislav; Mokranjac, Dejana; Seidel, Claus A M; Lamb, Don C

    2012-03-01

    Single-pair Förster resonance energy transfer (spFRET) experiments using single-molecule burst analysis on a confocal microscope are an ideal tool to measure inter- and intramolecular distances and dynamics on the nanoscale. Different techniques have been developed to maximize the amount of information available in spFRET burst analysis experiments. Multiparameter fluorescence detection (MFD) is used to monitor a variety of fluorescence parameters simultaneously and pulsed interleaved excitation (PIE) employs direct excitation of the acceptor to probe its presence and photoactivity. To calculate accurate FRET efficiencies from spFRET experiments with MFD or PIE, several calibration measurements are usually required. Herein, we demonstrate that by combining MFD with PIE information regarding all calibration factors as well as an accurate determination of spFRET histograms can be performed in a single measurement. In addition, the quality of overlap of the different detection volumes as well as the detection of acceptor photophysics can be investigated with MFD-PIE. Bursts containing acceptor photobleaching can be identified and excluded from further investigation while bursts that contain FRET dynamics are unaffected by this analysis. We have employed MFD-PIE to accurately analyze the effects of nucleotides and substrate on the interdomain separation in DnaK, the major bacterial heat shock protein 70 (Hsp70). The interdomain distance increases from 47 Å in the ATP-bound state to 84 Å in the ADP-bound state and slightly contracts to 77 Å when a substrate is bound. This is in contrast to what was observed for the mitochondrial member of the Hsp70s, Ssc1, supporting the notion of evolutionary specialization of Hsp70s for different cellular functions in different organisms and cell organelles. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Fluorescence resonance energy transfer in AOT/4-chlorophenol/m-xylene organogels

    Energy Technology Data Exchange (ETDEWEB)

    Dandapat, Manika; Mandal, Debabrata, E-mail: dmandal.chemistry@gmail.com

    2015-06-15

    Fluorescence Resonance Energy Transfer (FRET) between donor coumarins (C102 and C153) and acceptor Rhodamine 6G were studied in AOT/4-chlorophenol/m-xylene organogels. The gel comprises a three-dimensional network of fiber bundles trapping the m-xylene solvent. Each fiber is an aggregate of several strands, and each strand consists of a central columnar stack of the phenols, surrounded by AOT headgroups. Our acceptor is ionic so that it was concentrated near the polar center of the strand, while the neutral donors were likely distributed over a wider region. With C153 as donor, clear evidence of FRET (time-constant~100 ps) was found, which indicated that the donor and acceptor may reside in neighboring strands within the same fiber. However, with C102 as donor, FRET probably occurred over an ultrashort, sub-picosecond time-scale suggesting that the donor and acceptor in this case resided in close vicinity. Thus, C102 tends to localize near the polar centre of the strands, compared to the more hydrophobic C153, which prefers to occupy the relatively non-polar peripheral regions of the strands and fibers. - Highlights: • FRET between coumarin donors and Rhodamine 6G acceptor studied in AOT organogels. • With Coumarin 153 donor, a ~100 ps FRET component detected in both donor and acceptor fluorescence. • With Coumarin 102 donor, FRET component too short to be detected with a time-resolution of ~70 ps. • The FRET rates reveal crucial differences in donor–acceptor distances for the two coumarin donors.

  11. Image Processing for Bioluminescence Resonance Energy Transfer Measurement—BRET-Analyzer

    Directory of Open Access Journals (Sweden)

    Yan Chastagnier

    2018-01-01

    Full Text Available A growing number of tools now allow live recordings of various signaling pathways and protein-protein interaction dynamics in time and space by ratiometric measurements, such as Bioluminescence Resonance Energy Transfer (BRET Imaging. Accurate and reproducible analysis of ratiometric measurements has thus become mandatory to interpret quantitative imaging. In order to fulfill this necessity, we have developed an open source toolset for Fiji—BRET-Analyzer—allowing a systematic analysis, from image processing to ratio quantification. We share this open source solution and a step-by-step tutorial at https://github.com/ychastagnier/BRET-Analyzer. This toolset proposes (1 image background subtraction, (2 image alignment over time, (3 a composite thresholding method of the image used as the denominator of the ratio to refine the precise limits of the sample, (4 pixel by pixel division of the images and efficient distribution of the ratio intensity on a pseudocolor scale, and (5 quantification of the ratio mean intensity and standard variation among pixels in chosen areas. In addition to systematize the analysis process, we show that the BRET-Analyzer allows proper reconstitution and quantification of the ratiometric image in time and space, even from heterogeneous subcellular volumes. Indeed, analyzing twice the same images, we demonstrate that compared to standard analysis BRET-Analyzer precisely define the luminescent specimen limits, enlightening proficient strengths from small and big ensembles over time. For example, we followed and quantified, in live, scaffold proteins interaction dynamics in neuronal sub-cellular compartments including dendritic spines, for half an hour. In conclusion, BRET-Analyzer provides a complete, versatile and efficient toolset for automated reproducible and meaningful image ratio analysis.

  12. Intrinsic Tryptophan Fluorescence in the Detection and Analysis of Proteins: A Focus on Förster Resonance Energy Transfer Techniques

    Directory of Open Access Journals (Sweden)

    Amar B. T. Ghisaidoobe

    2014-12-01

    Full Text Available F resonance energy transfer (FRET occurs when the distance between a donor fluorophore and an acceptor is within 10 nm, and its application often necessitates fluorescent labeling of biological targets. However, covalent modification of biomolecules can inadvertently give rise to conformational and/or functional changes. This review describes the application of intrinsic protein fluorescence, predominantly derived from tryptophan (\\(\\uplambda_{\\textsc{ex}}\\sim\\ nm, \\(\\uplambda_{\\textsc{em}}\\sim\\ 350 nm, in protein-related research and mainly focuses on label-free FRET techniques. In terms of wavelength and intensity, tryptophan fluorescence is strongly influenced by its (or the proteinlocal environment, which, in addition to fluorescence quenching, has been applied to study protein conformational changes. Intrinsic F resonance energy transfer (iFRET, a recently developed technique, utilizes the intrinsic fluorescence of tryptophan in conjunction with target-specific fluorescent probes as FRET donors and acceptors, respectively, for real time detection of native proteins.

  13. Förster resonance energy transfer in hybrid associates of colloidal Ag2S quantum dots with thionine molecules

    Science.gov (United States)

    Ovchinnikov, Oleg V.; Smirnov, Mikhail S.; Kondratenko, Tamara S.; Ambrosevich, Sergey A.; Metlin, Mikhail T.; Grevtseva, Irina G.; Perepelitsa, Aleksey S.

    2017-12-01

    Nonradiative resonance energy transfer in hydrophilic hybrid associates of thionine molecules (TH+) with colloidal Ag2S quantum dots (QDs) with average diameter of 3.5 nm was studied. Photoluminescence spectra and its decay shown that for these systems the supplemental photosensitization of recombination luminescence of Ag2S QDs (1200 nm) from the region of TH+ fluorescence (618 nm) is possible. It was found that the average lifetime of TH+ molecules luminescence is shortened during their association with Ag2S QDs. Approximation of luminescence decay by stretched exponent with value of parameter β = 0.5 indicates on the inductive-resonance dipole-dipole (Förster) mechanism of nonradiative energy transfer (FRET). The efficiency of FRET was 0.29-0.41.

  14. Nonlinear Dynamics and Bifurcation Behavior of a 2-DOF Spring Resonator with End Stopper for Energy Harvesting

    Directory of Open Access Journals (Sweden)

    El Aroudi A.

    2014-01-01

    Full Text Available In this paper, the model of a two-degree-of-freedom (2-DOF spring resonator with end stopper for an energy harvesting application is presented. Then we characterize its nonlinear dynamical behavior by numerical simulations when some suitable parameters are varied. The system is formed by two resonators subject to external vibrational excitation and with an end stopper. We present the continuous time dynamical model of the system in the form of a switched fourth order differential equation. Harmonic vibrations are considered as the main ambient energy source for the system and its frequency response representing the RMS value of the displacement is first computed. The dynamical behavior is unveiled by computing state-space trajectories, timedomain series and FFT spectra and frequency response as the excitation amplitude is varied.

  15. Quantifying the influence of yellow fluorescent protein photoconversion on acceptor photobleaching-based fluorescence resonance energy transfer measurements

    Science.gov (United States)

    Seitz, Arne; Terjung, Stefan; Zimmermann, Timo; Pepperkok, Rainer

    2012-01-01

    Fluorescence resonance energy transfer (FRET) efficiency measurements based on acceptor photobleaching of yellow fluorescent protein (YFP) are affected by the fact that bleaching of YFP produces a fluorescent species that is detectable in cyan fluorescent protein (CFP) image channels. The presented quantitative measurement of this conversion makes it possible to correct the obtained FRET signal to increase the accuracy of intensity based CFP/YFP FRET measurements. The described method can additionally be used to compare samples with very different fluorescence levels.

  16. Morphology of the spectral resonance structure of the electromagnetic background noise in the range of 0.1–4 Hz at L = 5.2

    Directory of Open Access Journals (Sweden)

    A. G. Yahnin

    2003-03-01

    Full Text Available Continuous observations of fluctuations of the geomagnetic field at Sodankylä Geophysical Observatory (L = 5.2 were used for a comprehensive morphological study of the spectral resonance structure (SRS seen in the background electromagnetic noise in the frequency range of 0.1–4.0 Hz. It is shown that the occurrence rate of SRS is higher in the nighttime than in the daytime. The occurrence rate is higher in winter than in summer. The SRS frequencies and the difference between neighbouring eigenfrequencies (the frequency scale increase towards nighttime and decrease towards daytime. Both frequency scale and occurrence rate exhibit a clear tendency to decrease from minimum to maximum of the solar activity cycle. It is found that the occurrence rate of SRS decreases when geomagnetic activity increases. The SRS is believed to be a consequence of a resonator for Alfvén waves, which is suggested to exist in the upper ionosphere. According to the theory of the ionospheric Alfvén resonator (IAR, characteristics of SRS crucially depend on electron density in the F-layer maximum, as well as on the altitudinal scale of the density decay above the maximum.We compared the SRS morphological properties with predictions of the IAR theory. The ionospheric parameters needed for calculation were obtained from the ionosphere model (IRI-95, as well as from measurements made with the ionosonde in Sodankylä. We conclude that, indeed, the main morphological properties of SRS are explained on the basis of the IAR theory. The measured parameters of SRS can be used for improving the ionospheric models.Key words. Ionosphere (auroral ionosphere; wave propagation – Radio Science (electromagnetic noise and interference

  17. Morphology of the spectral resonance structure of the electromagnetic background noise in the range of 0.1–4 Hz at L = 5.2

    Directory of Open Access Journals (Sweden)

    J. Manninen

    Full Text Available Continuous observations of fluctuations of the geomagnetic field at Sodankylä Geophysical Observatory (L = 5.2 were used for a comprehensive morphological study of the spectral resonance structure (SRS seen in the background electromagnetic noise in the frequency range of 0.1–4.0 Hz. It is shown that the occurrence rate of SRS is higher in the nighttime than in the daytime. The occurrence rate is higher in winter than in summer. The SRS frequencies and the difference between neighbouring eigenfrequencies (the frequency scale increase towards nighttime and decrease towards daytime. Both frequency scale and occurrence rate exhibit a clear tendency to decrease from minimum to maximum of the solar activity cycle. It is found that the occurrence rate of SRS decreases when geomagnetic activity increases. The SRS is believed to be a consequence of a resonator for Alfvén waves, which is suggested to exist in the upper ionosphere. According to the theory of the ionospheric Alfvén resonator (IAR, characteristics of SRS crucially depend on electron density in the F-layer maximum, as well as on the altitudinal scale of the density decay above the maximum.We compared the SRS morphological properties with predictions of the IAR theory. The ionospheric parameters needed for calculation were obtained from the ionosphere model (IRI-95, as well as from measurements made with the ionosonde in Sodankylä. We conclude that, indeed, the main morphological properties of SRS are explained on the basis of the IAR theory. The measured parameters of SRS can be used for improving the ionospheric models.Key words. Ionosphere (auroral ionosphere; wave propagation – Radio Science (electromagnetic noise and interference

  18. Recent Advances in Nanoparticle-Based Förster Resonance Energy Transfer for Biosensing, Molecular Imaging and Drug Release Profiling

    Directory of Open Access Journals (Sweden)

    Nai-Tzu Chen

    2012-12-01

    Full Text Available Förster resonance energy transfer (FRET may be regarded as a “smart” technology in the design of fluorescence probes for biological sensing and imaging. Recently, a variety of nanoparticles that include quantum dots, gold nanoparticles, polymer, mesoporous silica nanoparticles and upconversion nanoparticles have been employed to modulate FRET. Researchers have developed a number of “visible” and “activatable” FRET probes sensitive to specific changes in the biological environment that are especially attractive from the biomedical point of view. This article reviews recent progress in bringing these nanoparticle-modulated energy transfer schemes to fruition for applications in biosensing, molecular imaging and drug delivery.

  19. Personal dose equivalent conversion coefficients for neutron fluence over the energy range of 20 to 250 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Mclean, Thomas D [Los Alamos National Laboratory; Justus, Alan L [Los Alamos National Laboratory; Gadd, S Milan [Los Alamos National Laboratory; Olsher, Richard H [RP-2; Devine, Robert T [RP-2

    2009-01-01

    Monte Carlo simulations were performed to extend existing neutron personal dose equivalent fluence-to-dose conversion coefficients to an energy of 250 MeV. Presently, conversion coefficients, H(p,slab)(10,alpha)/Phi, are given by ICRP-74 and ICRU-57 for a range of angles of radiation incidence (alpha = 0, 15, 30, 45, 60 and 75 degrees ) in the energy range from thermal to 20 MeV. Standard practice has been to base operational dose quantity calculations <20 MeV on the kerma approximation, which assumes that charged particle secondaries are locally deposited, or at least that charged particle equilibrium exists within the tally cell volume. However, with increasing neutron energy the kerma approximation may no longer be valid for some energetic secondaries such as protons. The Los Alamos Monte Carlo radiation transport code MCNPX was used for all absorbed dose calculations. Transport models and collision-based energy deposition tallies were used for neutron energies >20 MeV. Both light and heavy ions (HIs) (carbon, nitrogen and oxygen recoil nuclei) were transported down to a lower energy limit (1 keV for light ions and 5 MeV for HIs). Track energy below the limit was assumed to be locally deposited. For neutron tracks <20 MeV, kerma factors were used to obtain absorbed dose. Results are presented for a discrete set of angles of incidence on an ICRU tissue slab phantom.

  20. Time-Domain Microfluidic Fluorescence Lifetime Flow Cytometry for High-Throughput Förster Resonance Energy Transfer Screening

    Science.gov (United States)

    Nedbal, Jakub; Visitkul, Viput; Ortiz-Zapater, Elena; Weitsman, Gregory; Chana, Prabhjoat; Matthews, Daniel R; Ng, Tony; Ameer-Beg, Simon M

    2015-01-01

    Sensing ion or ligand concentrations, physico-chemical conditions, and molecular dimerization or conformation change is possible by assays involving fluorescent lifetime imaging. The inherent low throughput of imaging impedes rigorous statistical data analysis on large cell numbers. We address this limitation by developing a fluorescence lifetime-measuring flow cytometer for fast fluorescence lifetime quantification in living or fixed cell populations. The instrument combines a time-correlated single photon counting epifluorescent microscope with microfluidics cell-handling system. The associated computer software performs burst integrated fluorescence lifetime analysis to assign fluorescence lifetime, intensity, and burst duration to each passing cell. The maximum safe throughput of the instrument reaches 3,000 particles per minute. Living cells expressing spectroscopic rulers of varying peptide lengths were distinguishable by Förster resonant energy transfer measured by donor fluorescence lifetime. An epidermal growth factor (EGF)-stimulation assay demonstrated the technique's capacity to selectively quantify EGF receptor phosphorylation in cells, which was impossible by measuring sensitized emission on a standard flow cytometer. Dual-color fluorescence lifetime detection and cell-specific chemical environment sensing were exemplified using di-4-ANEPPDHQ, a lipophilic environmentally sensitive dye that exhibits changes in its fluorescence lifetime as a function of membrane lipid order. To our knowledge, this instrument opens new applications in flow cytometry which were unavailable due to technological limitations of previously reported fluorescent lifetime flow cytometers. The presented technique is sensitive to lifetimes of most popular fluorophores in the 0.5–5 ns range including fluorescent proteins and is capable of detecting multi-exponential fluorescence lifetime decays. This instrument vastly enhances the throughput of experiments involving

  1. GIOTTO ION MASS SPECTROMETER HIGH ENERGY RANGE DATA V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — A wide range of ion species and velocity distributions are expected to be found as the Giotto spacecraft traverses the coma of Halley's Comet. The outer coma is...

  2. Numerical calculation of the decay widths, the decay constants, and the decay energy spectra of the resonances of the delta-shell potential

    Energy Technology Data Exchange (ETDEWEB)

    Madrid, Rafael de la, E-mail: rafael.delamadrid@lamar.edu

    2017-06-15

    We express the resonant energies of the delta-shell potential in terms of the Lambert W function, and we calculate their decay widths and decay constants. The ensuing numerical results strengthen the interpretation of such decay widths and constants as a way to quantify the coupling between a resonance and the continuum. We calculate explicitly the decay energy spectrum of the resonances of the delta-shell potential, and we show numerically that the lineshape of such spectrum is not the same as, and can be very different from, the Breit–Wigner (Lorentzian) distribution. We argue that the standard Golden Rule cannot describe the interference of two resonances, and we show how to describe such interference by way of the decay energy spectrum of two resonant states.

  3. Numerical calculation of the decay widths, the decay constants, and the decay energy spectra of the resonances of the delta-shell potential

    Science.gov (United States)

    de la Madrid, Rafael

    2017-06-01

    We express the resonant energies of the delta-shell potential in terms of the Lambert W function, and we calculate their decay widths and decay constants. The ensuing numerical results strengthen the interpretation of such decay widths and constants as a way to quantify the coupling between a resonance and the continuum. We calculate explicitly the decay energy spectrum of the resonances of the delta-shell potential, and we show numerically that the lineshape of such spectrum is not the same as, and can be very different from, the Breit-Wigner (Lorentzian) distribution. We argue that the standard Golden Rule cannot describe the interference of two resonances, and we show how to describe such interference by way of the decay energy spectrum of two resonant states.

  4. Shear-horizontal vibration modes of an oblate elliptical cylinder and energy trapping in contoured acoustic wave resonators.

    Science.gov (United States)

    He, Huijing; Yang, Jiashi; Kosinski, John A

    2012-08-01

    We study shear-horizontal free vibrations of an elastic cylinder with an oblate elliptical cross section and a traction-free surface. Exact vibration modes and frequencies are obtained. The results show the existence of thickness-shear and thickness-twist modes. The energy-trapping behavior of these modes is examined. Trapped modes are found wherein the vibration energy is largely confined to the central portion of the cross section and little vibration energy is found at the edges. It is also shown that face-shear modes are not allowed in such a cylinder. The results are useful for the understanding of the energy trapping phenomenon in contoured acoustic wave resonators.

  5. Can nanophotonics control the Förster resonance energy transfer efficiency?

    DEFF Research Database (Denmark)

    Blum, C.; Zijlstra, N.; Lagendijk, A.

    2013-01-01

    precisely-defined, isolated, and efficient donor-acceptor pairs. The FRET pairs are dye molecules that covalently bound to the opposite ends of a 15 basepair long double-stranded with a precisely defined distance of 6.8 nm. Control over the LDOS is realized by positioning the FRET systems at well...... from photovoltaics and lighting, to probing molecular distances and interactions.It is an intriguing open question whether the FRET rate γFRET and the energy transfer efficiency ηFRET can also be controlled by the nanoscale optical environment, characterized by the local density of optical states (LDOS......-defined distances (ranging from 60 nm to 270 nm) from a metallic mirror. The energy transfer rate γFRET and efficiency ηFRET are obtained by measuring the donor emission rate γDA in presence and the rate γD in absence of the acceptor using time-correlated single-photon counting based lifetime imaging. Our data...

  6. Energy storage label : A method for comparing storage systems over all ranges

    NARCIS (Netherlands)

    Christian van Someren; F. Pierie

    2015-01-01

    This report describes the creation and use of a database for energy storage technologies which was developed in conjunction with Netbeheer Nederland and the Hanze University of Applied Sciences. This database can be used to make comparisons between a selection of storage technologies and will

  7. An all-solid-state microsecond-range quasi-square pulse generator based on fractional-turn ratio saturable pulse transformer and anti-resonance network.

    Science.gov (United States)

    Chen, Rong; Yang, Jianhua; Cheng, Xinbing; Pan, Zilong

    2017-03-01

    High voltage pulse generators are widely applied in a number of fields. Defense and industrial applications stimulated intense interests in the area of pulsed power technology towards the system with high power, high repetition rate, solid state characteristics, and compact structure. An all-solid-state microsecond-range quasi-square pulse generator based on a fractional-turn ratio saturable pulse transformer and anti-resonance network is proposed in this paper. This generator consists of a charging system, a step-up system, and a modulating system. In this generator, the fractional-turn ratio saturable pulse transformer is the key component since it acts as a step-up transformer and a main switch during the working process. Demonstrative experiments show that if the primary storage capacitors are charged to 400 V, a quasi-square pulse with amplitude of about 29 kV can be achieved on a 3500 Ω resistive load, as well as the pulse duration (full width at half maximum) of about 1.3 μs. Preliminary repetition rate experiments are also carried out, which indicate that this pulse generator could work stably with the repetition rates of 30 Hz and 50 Hz. It can be concluded that this kind of all-solid-state microsecond-range quasi-square pulse generator can not only lower both the operating voltage of the primary windings and the saturable inductance of the secondary windings, thus ideally realizing the magnetic switch function of the fractional-turn ratio saturable pulse transformer, but also achieve a quasi-square pulse with high quality and fixed flat top after the modulation of a two-section anti-resonance network. This generator can be applied in areas of large power microwave sources, sterilization, disinfection, and wastewater treatment.

  8. Spin-unrestricted random-phase approximation with range separation: Benchmark on atomization energies and reaction barrier heights

    CERN Document Server

    Mussard, Bastien; Angyan, Janos; Toulouse, Julien

    2015-01-01

    We consider several spin-unrestricted random-phase approximation (RPA) variants for calculating correlation energies, with and without range separation, and test them on datasets of atomization energies and reaction barrier heights. We show that range separation greatly improves the accuracy of all RPA variants for these properties. Moreover, we show that a RPA variant with exchange, hereafter referred to as RPAx-SO2, first proposed by Sz-abo and Ostlund [A. Szabo and N. S. Ostlund, J. Chem. Phys. 67, 4351 (1977)] in a spin-restricted closed-shell formalism, and extended here to a spin-unrestricted formalism, provides on average the most accurate range-separated RPA variant for atomization energies and reaction barrier heights. Since this range-separated RPAx-SO2 method had already been shown to be among the most accurate range-separated RPA variants for weak intermolecular interactions [J. Toulouse, W. Zhu, A. Savin, G. Jansen, and J. G. {\\'A}ngy{\\'a}n, J. Chem. Phys. 135, 084119 (2011)], this works confirms...

  9. High energy storage density over a broad temperature range in sodium bismuth titanate-based lead-free ceramics.

    Science.gov (United States)

    Yang, Haibo; Yan, Fei; Lin, Ying; Wang, Tong; Wang, Fen

    2017-08-18

    A series of (1-x)Bi0.48La0.02Na0.48Li0.02Ti0.98Zr0.02O3-xNa0.73Bi0.09NbO3 ((1-x)LLBNTZ-xNBN) (x = 0-0.14) ceramics were designed and fabricated using the conventional solid-state sintering method. The phase structure, microstructure, dielectric, ferroelectric and energy storage properties of the ceramics were systematically investigated. The results indicate that the addition of Na0.73Bi0.09NbO3 (NBN) could decrease the remnant polarization (P r ) and improve the temperature stability of dielectric constant obviously. The working temperature range satisfying TCC 150 °C ≤±15% of this work spans over 400 °C with the compositions of x ≥ 0.06. The maximum energy storage density can be obtained for the sample with x = 0.10 at room temperature, with an energy storage density of 2.04 J/cm(3) at 178 kV/cm. In addition, the (1-x)LLBNTZ-xNBN ceramics exhibit excellent energy storage properties over a wide temperature range from room temperature to 90 °C. The values of energy storage density and energy storage efficiency is 0.91 J/cm(3) and 79.51%, respectively, for the 0.90LLBNTZ-0.10NBN ceramic at the condition of 100 kV/cm and 90 °C. It can be concluded that the (1-x)LLBNTZ-xNBN ceramics are promising lead-free candidate materials for energy storage devices over a broad temperature range.

  10. Energy saving mechanisms, collective behavior and the variation range hypothesis in biological systems: A review

    OpenAIRE

    Trenchard, Hugh; Perc, Matjaz

    2016-01-01

    Energy saving mechanisms are ubiquitous in nature. Aerodynamic and hydrodynamic drafting, vortice uplift, Bernoulli suction, thermoregulatory coupling, path following, physical hooks, synchronization, and cooperation are only some of the better-known examples. While drafting mechanisms also appear in non-biological systems such as sedimentation and particle vortices, the broad spectrum of these mechanisms appears more diversely in biological systems including bacteria, spermatozoa, various aq...

  11. Physics of reflective optics for the soft gamma-ray photon energy range

    DEFF Research Database (Denmark)

    Fernández-Perea, Mónica; Descalle, Marie-Anne; Soufli, Regina

    2013-01-01

    and the disagreement between experimental and theoretical optical properties of materials in the hard x-ray and gamma-ray regimes. Here, we demonstrate that multilayer reflective optics can operate efficiently and according to classical wave physics up to photon energies of at least 384 keV. We also use particle...... and lenses) and crystal monochromators have been available until now. © 2013 American Physical Society....

  12. Higher lying resonances in low-energy electron scattering with carbon monoxide

    CERN Document Server

    Dora, Amar; Chakrabarti, Kalyan

    2016-01-01

    R-matrix calculations on electron collisions with CO are reported whose aim is to identify any higher-lying resonances above the well-reported and lowest $^2\\Pi$ resonance at about 1.6~eV. Extensive tests with respect to basis sets, target models and scattering models are performed. The final results are reported for the larger cc-pVTZ basis set using a 50 state close-coupling (CC) calculation. The Breit-Wigner eigenphase sum and the time-delay methods are used to detect and fit any resonances. Both these methods find a very narrow $^2\\Sigma^+$ symmetry Feshbach-type resonance very close to the target excitation threshold of the b $^3\\Sigma^+$ state which lies at 12.9 eV in the calculations. This resonance is seen in the CC calculation using cc-pVTZ basis set while a CC calculation using the cc-pVDZ basis set does not produce this feature. The electronic structure of CO$^-$ is analysed in the asymptotic region, 45 molecular states are found to correlate with states dissociating to an anion and an atom. Electr...

  13. On the possibility of ephedrine detection: time-resolved fluorescence resonance energy transfer (FRET)-based approach.

    Science.gov (United States)

    Varriale, Antonio; Marzullo, Vincenzo Manuel; Di Giovanni, Stefano; Scala, Andrea; Capo, Alessandro; Majoli, Adelia; Pennacchio, Angela; Staiano, Maria; D'Auria, Sabato

    2016-09-01

    Ephedrine is one of the main precursor compounds used in the illegal production of amphetamines and related drugs. Actually, conventional analytical methods such as high-performance liquid chromatography (HPLC), capillary electrophoresis (CE), and gas chromatography-mass spectrometry (GC-MS) are used for the detection of ephedrine; sadly, these methods require qualified personnel and are time-consuming and expensive. In order to overcome these problems, in recent years, different methods have been developed based on the surface plasmon resonance (SPR) and electrochemical method. In this work, we present a simple, rapid, and effective method to detect the presence of ephedrine in solution, based on competitive fluorescence resonance energy transfer (FRET) assay. The antibody anti-ephedrine and ephedrine derivative were produced and labeled respectively, with two different fluorescent probes (donor and acceptor). The change in FRET signal intensity between donor and acceptor ephedrine compounds gives the possibility of detecting ephedrine traces of at least 0.81 ± 0.04 ppm (LOD). Graphical abstract A new Time-resolved Fluorescence Resonance Energy Transfer (FRET) assay for ephedrine detection.

  14. Energy Analysis of Road Accidents Based on Close-Range Photogrammetry

    Directory of Open Access Journals (Sweden)

    Alejandro Morales

    2015-11-01

    Full Text Available This paper presents an efficient and low-cost approach for energy analysis of road accidents using images obtained using consumer-grade digital cameras and smartphones. The developed method could be used by security forces in order to improve the qualitative and quantitative analysis of traffic accidents. This role of the security forces is crucial to settle arguments; consequently, the remote and non-invasive collection of accident related data before the scene is modified proves to be essential. These data, taken in situ, are the basis to perform the necessary calculations, basically the energy analysis of the road accident, for the corresponding expert reports and the reconstruction of the accident itself, especially in those accidents with important damages and consequences. Therefore, the method presented in this paper provides the security forces with an accurate, three-dimensional, and scaled reconstruction of a road accident, so that it may be considered as a support tool for the energy analysis. This method has been validated and tested with a real crash scene simulated by the local police in the Academy of Public Safety of Extremadura, Spain.

  15. Reexamination of the Energy Levels of 15F by 14O + 1H ElasticResonance Scattering with BEARS

    Energy Technology Data Exchange (ETDEWEB)

    Guo, F.Q.; Powell, J.; Lee, D.W.; Leitner, D.; McMahan, M.A.; Moltz, D.M.; O' Neil, J.P.; Perajarvi, K.; Phair, L.; Ramsey, C.A.; Xu,X.J.; Cerny, Joseph

    2005-05-30

    The energy levels of 15F have been measured by the p(14O,p)14O reaction. The 120 MeV 14O radioactive ion beam was produced by the BEARS coupled cyclotron system at an intensity averaging 1x104 particles/second on target. Energy calibration was obtained using resonances from the p(14N,p)14N reaction. The two lowest resonances in 15F were fitted with an R-matrix calculation. The fit to the ground state had Jp = 1/2+ at 1.23+-0.05 MeV (width 0.5-0.84 MeV), and the first excited state was Jp=5/2+ at 2.81+-0.02 MeV (width 0.30+-0.06 MeV), both relative to the mass-energy of the proton and 14O. The 15F ground state energy supports the disappearance of the Z=8 proton magic number for odd Z, Tz=-3/2 nuclei.

  16. Inelastic processes in Na$^{+}-$Ne, Ar and Ne$^{+},$ Ar$^{+}-$Na collisions in energy range $0.5-14$ keV

    CERN Document Server

    Lomsadze, R A; Kezerashvili, R Ya

    2015-01-01

    Absolute cross sections for charge-exchange, ionization and excitation in Na$% ^{+}-$Ne and Na$^{+}-$Ar collisions were measured in the ion energy range $% 0.5-10$ keV using a refined version of a capacitor method, and collision and optical spectroscopy methods simultaneously in the same experimental set-up. Ionization cross sections for Ne$^{+}-$Na and Ar$^{+}-$Na collisions are measured at the energies of $2-14$ keV using a crossed-beam spectroscopy method. The experimental data and the schematic correlation diagrams are used to analyze and determine the mechanisms for these processes. For the charge-exchange process in Na$^{+}$ $-$Ar collisions two nonadiabatic regions are revealed and mechanisms responsible for these regions are explained. Structural peculiarity on the excitation function for the resonance lines of argon atoms in Na$^{+}$ $-$Ar collisions are observed and the possible mechanisms of this phenomenon are explored. The measured ionization cross sections for Na$^{+}-$Ne and Ne$^{+}-$Na collisi...

  17. Characterization and inhibition of norovirus proteases of genogroups I and II using a fluorescence resonance energy transfer assay

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Kyeong-Ok [Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, KS 66506 (United States); Takahashi, Daisuke; Prakash, Om [Department of Biochemistry, Kansas State University, Manhattan, KS 66506 (United States); Kim, Yunjeong, E-mail: ykim@vet.ksu.edu [Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, KS 66506 (United States)

    2012-02-20

    Noroviruses are the major cause of food- or water-borne gastroenteritis outbreaks in humans. The norovirus protease that cleaves a large viral polyprotein to nonstructural proteins is essential for virus replication and an attractive target for antiviral drug development. Noroviruses show high genetic diversity with at least five genogroups, GI-GV, of which GI and GII are responsible for the majority of norovirus infections in humans. We cloned and expressed proteases of Norwalk virus (GI) and MD145 virus (GII) and characterized the enzymatic activities with fluorescence resonance energy transfer substrates. We demonstrated that the GI and GII proteases cleaved the substrates derived from the naturally occurring cleavage site in the open reading frame (ORF) 1 of G1 norovirus with similar efficiency, and that enzymatic activity of both proteases was inhibited by commercial protease inhibitors including chymostatin. The interaction of chymostatin to Norwalk virus protease was validated by nuclear magnetic resonance (NMR) spectroscopy.

  18. A satellite-borne ion mass spectrometer for the energy range 0 to 16 keV

    Science.gov (United States)

    Balsiger, H.; Eberhardt, P.; Geiss, J.; Ghielmetti, A.; Walker, H. P.; Young, D. T.; Loidl, H.; Rosenbauer, H.

    1976-01-01

    The Ion Composition Experiment (ICE) on GEOS represents the first comprehensive attempt to measure the positive ion composition at high altitudes in the magnetosphere. Due to the heterogeneous nature of the magnetospheric plasma a novel mass spectrometer has been developed to cover the mass per charge range from H-1(+) to beyond Ba-138(+) and the energy per charge range from 0 to 16 keV/e. The ICE consists primarily of a cylindrical electrostatic analyzer followed by a curved analyzer incorporating crossed magnetic and electric fields. This combination has limited angular and energy focusing properties, but it maintains a mass resolution of about 4 over a wide range in energy and mass, sufficient for the objectives of measuring plasmas of both solar and terrestrial origin. High sensitivity and low background should allow measurements of rarer ion constituents down to flux levels of 0.01 ions/sq cm sec ster eV. A sophisticated electronics combined with powerful ground computer and telecommand systems allow for very efficient scanning of the mass-energy space.

  19. Reconfigurable Resonant Regulating Rectifier With Primary Equalization for Extended Coupling- and Loading-Range in Bio-Implant Wireless Power Transfer.

    Science.gov (United States)

    Li, Xing; Meng, Xiaodong; Tsui, Chi-Ying; Ki, Wing-Hung

    2015-12-01

    Wireless power transfer using reconfigurable resonant regulating (R(3)) rectification suffers from limited range in accommodating varying coupling and loading conditions. A primary-assisted regulation principle is proposed to mitigate these limitations, of which the amplitude of the rectifier input voltage on the secondary side is regulated by accordingly adjusting the voltage amplitude Veq on the primary side. A novel current-sensing method and calibration scheme track Veq on the primary side. A ramp generator simultaneously provides three clock signals for different modules. Both the primary equalizer and the R(3) rectifier are implemented as custom integrated circuits fabricated in a 0.35 μm CMOS process, with the global control implemented in FPGA. Measurements show that with the primary equalizer, the workable coupling and loading ranges are extended by 250% at 120 mW load and 300% at 1.2 cm coil distance compared to the same system without the primary equalizer. A maximum rectifier efficiency of 92.5% and a total system efficiency of 62.4% are demonstrated.

  20. Renormalized energy of ground and first excited state of Fröhlich polaron in the range of weak coupling

    Directory of Open Access Journals (Sweden)

    M.V. Tkach

    2015-09-01

    Full Text Available The partial summing of infinite range of diagrams for the two-phonon mass operator of polaron described by Frohlich Hamiltonian is performed using the Feynman-Pines diagram technique. The renormalized spectral parameters of ground and first excited (phonon repeat polaron state are accurately calculated for the weak electron-phonon coupling at T=0 K. It is shown that the stronger electron-phonon interaction shifts the energy of both states into low-energy region of the spectra. The ground state stays stationary and the excited one - decays at bigger coupling constant.

  1. Steady-State Equilibrium Phase Inversion Recovery ON-resonant Water Suppression (IRON) Magnetic Resonance Angiography in Conjunction with Superparamagnetic Nanoparticles. A Robust Technique for Imaging within a Wide Range of Contrast Agent Dosages

    Science.gov (United States)

    Gitsioudis, Gitsios; Stuber, Matthias; Arend, Ingolf; Thomas, Moritz; Yu, Jing; Hilbel, Thomas; Giannitsis, Evangelos; Katus, Hugo A.; Korosoglou, Grigorios

    2012-01-01

    Objectives To investigate the ability of inversion recovery ON-resonant water suppression (IRON) in conjunction with P904 (superparamagnetic nanoparticles which consisting of a maghemite core coated with a low-molecular-weight amino-alcohol derivative of glucose) to perform steady-state equilibrium phase magnetic resonance angiography (MRA) over a wide dose range. Materials and Methods Experiments were approved by the institutional animal care committee. Rabbits (n=12) were imaged at baseline and serially after the administration of 10 incremental dosages of 0.57–5.7 mgFe/Kg P904. Conventional T1-weighted and IRON MRA were obtained on a clinical 1.5-T scanner to image the thoracic and abdominal aorta, and peripheral vessels. Contrast-to-noise ratios (CNR) and vessel sharpness were quantified. Results Using IRON MRA, CNR and vessel sharpness progressively increased with incremental dosages of the contrast agent P904, exhibiting constantly higher contrast values than T1-weighted MRA over a very wide range of contrast agent doses (CNR of 18.8±5.6 for IRON versus 11.1±2.8 for T1-weighted MRA at 1.71 mgFe/kg, p=0.02 and 19.8±5.9 for IRON versus −0.8±1.4 for T1-weighted MRA at 3.99 mgFe/kg, p=0.0002). Similar results were obtained for vessel sharpness in peripheral vessels, (Vessel sharpness of 46.76±6.48% for IRON versus 33.20±3.53% for T1-weighted MRA at 1.71 mgFe/Kg, p=0.002, and of 48.66±5.50% for IRON versus 19.00±7.41% for T1-weighted MRA at 3.99 mgFe/Kg, p=0.003). Conclusion Our study suggests that quantitative CNR and vessel sharpness after the injection of P904 are consistently higher for IRON MRA when compared to conventional T1-weighted MRA. These findings apply for a wide range of contrast agent dosages. PMID:23418107

  2. Local orientational order in liquids revealed by resonant vibrational energy transfer

    NARCIS (Netherlands)

    Panman, M.R.; Shaw, D.J.; Ensing, B.; Woutersen, S.

    2014-01-01

    We demonstrate that local orientational ordering in a liquid can be observed in the decay of the vibrational anisotropy caused by resonant transfer of vibrational excitations between its constituent molecules. We show that the functional form of this decay is determined by the (distribution of)

  3. Fluorescence resonance energy transfer imaging of cell signaling from in vitro to in vivo: basis of biosensor construction, live imaging, and image processing.

    Science.gov (United States)

    Aoki, Kazuhiro; Kamioka, Yuji; Matsuda, Michiyuki

    2013-05-01

    The progress in imaging technology with fluorescent proteins has uncovered a wide range of biological processes in developmental biology. In particular, genetically-encoded biosensors based on the principle of fluorescence resonance energy transfer (FRET) have been used to visualize spatial and temporal dynamics of intracellular signaling in living cells. However, development of sensitive FRET biosensors and their application to developmental biology remain challenging tasks, which has prevented their widespread use in developmental biology. In this review, we first overview general procedures and tips of imaging with FRET biosensors. We then describe recent advances in FRET imaging - namely, the use of optimized backbones for intramolecular FRET biosensors and transposon-mediated gene transfer to generate stable cell lines and transgenic mice expressing FRET biosensors. Finally, we discuss future perspectives of FRET imaging in developmental biology. © 2013 The Authors Development, Growth & Differentiation © 2013 Japanese Society of Developmental Biologists.

  4. Design of an Activity-Based Probe for Human Neutrophil Elastase: Implementation of the Lossen Rearrangement To Induce Förster Resonance Energy Transfers.

    Science.gov (United States)

    Schulz-Fincke, Anna-Christina; Tikhomirov, Alexander S; Braune, Annett; Girbl, Tamara; Gilberg, Erik; Bajorath, Jürgen; Blaut, Michael; Nourshargh, Sussan; Gütschow, Michael

    2018-01-16

    Human neutrophil elastase is an important regulator of the immune response and plays a role in host defense mechanisms and further physiological processes. The uncontrolled activity of this serine protease may cause severe tissue alterations and impair inflammatory states. The design of an activity-based probe for human neutrophil elastase reported herein relies on a sulfonyloxyphthalimide moiety as a new type of warhead that is linker-connected to a coumarin fluorophore. The inhibitory potency of the activity-based probe was assessed against several serine and cysteine proteases, and the selectivity for human neutrophil elastase (Ki = 6.85 nM) was determined. The adequate fluorescent tag of the probe allowed for the in-gel fluorescence detection of human neutrophil elastase in the low nanomolar range. The coumarin moiety and the anthranilic acid function of the probe, produced in the course of a Lossen rearrangement, were part of two different Förster resonance energy transfers.

  5. High-energy ion-implantation-induced gettering of copper in silicon beyond the projected ion range: The trans-projected-range effect

    Science.gov (United States)

    Gueorguiev, Y. M.; Kögler, R.; Peeva, A.; Mücklich, A.; Panknin, D.; Yankov, R. A.; Skorupa, W.

    2000-11-01

    Five different species, namely B, Si, P, Ge, and As, were implanted at MeV energies into (100)-oriented n-type Czohralski Si, in order to form deep gettering layers during the subsequent annealing. Then the samples were contaminated with Cu by implanting the impurity on the backface and performing additional annealing. The resulting Cu depth distributions were measured by secondary ion mass spectrometry. Strong gettering of Cu atoms beyond the projected ion range RP and formation of a well-defined separate Cu gettering band therein is found for P and As implants. We call this phenomenon the "trans-RP effect." It arises from the presence of a significant amount of defects in the regions much deeper than RP. Their gettering ability is higher than that of the extended defects around RP, as the amount of Cu atoms gettered beyond RP is, especially for the P implants, much greater than that in the implanted gettering layer at RP. These deep defects have not been detected by transmission electron microscopy, and we suggest that they are small interstitial clusters. A mechanism responsible for the migration of self-interstitials from RP into the trans-RP region and their clustering therein is proposed. An explanation is given of the possible reasons for the differences in the results for the P+ and As+ implants.

  6. Electrolytes for Use in High Energy Lithium-ion Batteries with Wide Operating Temperature Range

    Science.gov (United States)

    Smart, Marshall C.; Ratnakumar, B. V.; West, W. C.; Whitcanack, L. D.; Huang, C.; Soler, J.; Krause, F. C.

    2012-01-01

    Met programmatic milestones for program. Demonstrated improved performance with wide operating temperature electrolytes containing ester co-solvents (i.e., methyl butyrate) containing electrolyte additives in A123 prototype cells: Previously demonstrated excellent low temperature performance, including 11C rates at -30 C and the ability to perform well down to -60 C. Excellent cycle life at room temperature has been displayed, with over 5,000 cycles being demonstrated. Good high temperature cycle life performance has also been achieved. Demonstrated improved performance with methyl propionate-containing electrolytes in large capacity prototype cells: Demonstrated the wide operating temperature range capability in large cells (12 Ah), successfully scaling up technology from 0.25 Ah size cells. Demonstrated improved performance at low temperature and good cycle life at 40 C with methyl propionate-based electrolyte containing increasing FEC content and the use of LiBOB as an additive. Utilized three-electrode cells to investigate the electrochemical characteristics of high voltage systems coupled with wide operating temperature range electrolytes: From Tafel polarization measurements on each electrode, it is evident the NMC-based cathode displays poor lithium kinetics (being the limiting electrode). The MB-based formulations containing LiBOB delivered the best rate capability at low temperature, which is attributed to improved cathode kinetics. Whereas, the use of lithium oxalate as an additive lead to the highest reversible capacity and lower irreversible losses.

  7. Characterisation of a detector based on microchannel plates for electrons in the energy range 10 20 keV

    Science.gov (United States)

    Moldovan, G.; Matheson, J.; Derbyshire, G.; Kirkland, A.

    2008-11-01

    As part of a feasibility study into the use of novel electron detectors for an X-ray photoelectron emission microscope (XPEEM), we have characterised a detector based on microchannel plates (MCPs), a phosphor screen and a CCD camera. For XPEEM, an imaging detector is required for electrons in the energy range 10-20 keV. This type of detector is a standard fitment on commercial instruments and we have studied its performance in some detail in order to provide a baseline against which to evaluate future detector technologies. We present detective quantum efficiency (DQE), noise power spectrum (NPS) and modulation transfer function (MTF) measurements of a commercial detector, in the energy range of interest, as a function of the detector bias voltage.

  8. Observation of short range three-particle correlations in e+e- annihilations at LEP energies

    CERN Document Server

    Abreu, P; Adye, T; Agasi, E; Ajinenko, I; Aleksan, Roy; Alekseev, G D; Allport, P P; Almehed, S; Alvsvaag, S J; Amaldi, Ugo; Amato, S; Andreazza, A; Andrieux, M L; Antilogus, P; Apel, W D; Arnoud, Y; Augustin, J E; Augustinus, A; Baillon, Paul; Bambade, P; Barate, R; Barbiellini, Guido; Bardin, Dimitri Yuri; Barker, G J; Baroncelli, A; Barrio, J A; Bartl, Walter; Barão, F; Bates, M J; Battaglia, Marco; Baubillier, M; Baudot, J; Becks, K H; Begalli, M; Beillière, P; Belokopytov, Yu A; Belous, K S; Benvenuti, Alberto C; Berggren, M; Bertrand, D; Bianchi, F; Bigi, M; Bilenky, S M; Billoir, P; Bloch, D; Blume, M; Blyth, S; Bocci, V; Bolognese, T; Bonesini, M; Bonivento, W; Booth, P S L; Borisov, G; Bosio, C; Bosworth, S; Botner, O; Bouquet, B; Bourdarios, C; Bowcock, T J V; Bozzo, M; Branchini, P; Brand, K D; Brenner, R A; Bricman, C; Brillault, L; Brown, R C A; Brunet, J M; Brückman, P; Bugge, L; Buran, T; Buys, A; Bärring, O; Caccia, M; Calvi, M; Camacho-Rozas, A J; Camporesi, T; Canale, V; Canepa, M; Cankocak, K; Cao, F; Carena, F; Carrilho, P; Carroll, L; Caso, Carlo; Castillo-Gimenez, M V; Cattai, A; Cavallo, F R; Cerrito, L; Chabaud, V; Charpentier, P; Chaussard, L; Chauveau, J; Checchia, P; Chelkov, G A; Chierici, R; Chochula, P; Chorowicz, V; Cindro, V; Collins, P; Contreras, J L; Contri, R; Cortina, E; Cosme, G; Cossutti, F; Crawley, H B; Crennell, D J; Crosetti, G; Cuevas-Maestro, J; Czellar, S; D'Almagne, B; Da Silva, W; Dahl-Jensen, Erik; Dahm, J; Dam, M; Damgaard, G; Daum, A; Dauncey, P D; Davenport, Martyn; De Angelis, A; De Boeck, H; De Brabandere, S; De Clercq, C; De Lotto, B; De Min, A; De Paula, L S; De Saint-Jean, C; Defoix, C; Della Ricca, G; Delpierre, P A; Demaria, N; Di Ciaccio, Lucia; Dijkstra, H; Djama, F; Dolbeau, J; Doroba, K; Dracos, M; Drees, J; Drees, K A; Dris, M; Dufour, Y; Dupont, F; Dönszelmann, M; Edsall, D M; Ehret, R; Eigen, G; Ekelöf, T J C; Ekspong, Gösta; Elsing, M; Engel, J P; Ershaidat, N; Erzen, B; Espirito-Santo, M C; Falk, E; Fassouliotis, D; Feindt, Michael; Fenyuk, A; Ferrer, A; Filippas-Tassos, A; Firestone, A; Fischer, P A; Fokitis, E; Fontanelli, F; Formenti, F; Franek, B J; Frenkiel, P; Fries, D E C; Frodesen, A G; Frühwirth, R; Fulda-Quenzer, F; Fuster, J A; Föth, H; Fürstenau, H; Galloni, A; Gamba, D; Gandelman, M; García, C; García, J; Gaspar, C; Gasparini, U; Gavillet, P; Gazis, E N; Gelé, D; Gerber, J P; Gibbs, M; Gillespie, D; Gokieli, R; Golob, B; Gopal, Gian P; Gorn, L; Gracco, Valerio; Graziani, E; Grosdidier, G; Gunnarsson, P; Guy, J; Guz, Yu; Górski, M; Günther, M; Haedinger, U; Hahn, F; Hahn, M; Hahn, S; Hajduk, Z; Hallgren, A; Hamacher, K; Hao, W; Harris, F J; Hedberg, V; Henriques, R P; Hernández, J J; Herquet, P; Herr, H; Hessing, T L; Higón, E; Hilke, Hans Jürgen; Hill, T S; Holmgren, S O; Holt, P J; Holthuizen, D J; Houlden, M A; Huet, K; Hultqvist, K; Ioannou, P; Jackson, J N; Jacobsson, R; Jalocha, P; Janik, R; Jarlskog, G; Jarry, P; Jean-Marie, B; Johansson, E K; Joram, Christian; Juillot, P; Jönsson, L B; Jönsson, P E; Kaiser, M; Kalmus, George Ernest; Kapusta, F; Karlsson, M; Karvelas, E; Katargin, A; Katsanevas, S; Katsoufis, E C; Keränen, R; Khomenko, B A; Khovanskii, N N; King, B J; Kjaer, N J; Klein, H; Klovning, A; Kluit, P M; Kokkinias, P; Koratzinos, M; Kostyukhin, V; Kourkoumelis, C; Kramer, P H; Krammer, Manfred; Kreuter, C; Kronkvist, I J; Krumshtein, Z; Krupinski, W; Królikowski, J; Kubinec, P; Kucewicz, W; Kurvinen, K L; Kuznetsov, O; Köhne, J H; Köne, B; La Vaissière, C de; Lacasta, C; Laktineh, I; Lamblot, S; Lamsa, J; Lanceri, L; Lane, D W; Langefeld, P; Lapin, V; Last, I; Laugier, J P; Lauhakangas, R; Leder, Gerhard; Ledroit, F; Lefébure, V; Legan, C K; Leitner, R; Lemoigne, Y; Lemonne, J; Lenzen, Georg; Lepeltier, V; Lesiak, T; Liko, D; Lindner, R; Lipniacka, A; Lippi, I; Lokajícek, M; Loken, J G; Loukas, D; Lutz, P; Lyons, L; López, J M; López-Aguera, M A; López-Fernandez, A; Lörstad, B; MacNaughton, J N; Maehlum, G; Maio, A; Malychev, V; Mandl, F; Marco, J; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Maron, T; Martí i García, S; Martínez-Rivero, C; Martínez-Vidal, F; Maréchal, B; Matorras, F; Matteuzzi, C; Matthiae, Giorgio; Mazzucato, M; McCubbin, M L; McKay, R; McNulty, R; Medbo, J; Meroni, C; Meyer, W T; Michelotto, M; Migliore, E; Mirabito, L; Mitaroff, Winfried A; Mjörnmark, U; Moa, T; Monge, M R; Morettini, P; Mundim, L M; Murray, W J; Muryn, B; Myagkov, A; Myatt, Gerald; Mönig, K; Møller, R; Müller, H; Naraghi, F; Navarria, Francesco Luigi; Navas, S; Negri, P; Neumann, W; Neumeister, N; Nicolaidou, R; Nielsen, B S; Nieuwenhuizen, M; Nikolaenko, V; Niss, P; Nomerotski, A; Normand, Ainsley; Némécek, S; Oberschulte-Beckmann, W; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, Risto; Ouraou, A; Paganini, P; Paganoni, M; Pagès, P; Palka, H; Papadopoulou, T D; Pape, L; Parkes, C; Parodi, F; Passeri, A; Pegoraro, M; Peralta, L; Pernegger, H; Pernicka, Manfred; Perrotta, A; Petridou, C; Petrolini, A; Phillips, H T; Piana, G; Pierre, F; Pimenta, M; Plaszczynski, S; Podobrin, O; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Prest, M; Privitera, P; Pukhaeva, N; Pullia, Antonio; Radojicic, D; Ragazzi, S; Rahmani, H; Rames, J; Ratoff, P N; Read, A L; Reale, M; Rebecchi, P; Redaelli, N G; Regler, Meinhard; Reid, D; Renton, P B; Resvanis, L K; Richard, F; Richardson, J; Rinaudo, G; Ripp, I; Romero, A; Roncagliolo, I; Ronchese, P; Roos, L; Rosenberg, E I; Rosso, E; Roudeau, Patrick; Rovelli, T; Ruhlmann-Kleider, V; Ruiz, A; Rídky, J; Rückstuhl, W; Saarikko, H; Sacquin, Yu; Sadovskii, A; Sajot, G; Salt, J; Sannino, M; Schneider, H; Schyns, M A E; Sciolla, G; Scuri, F; Sedykh, Yu; Segar, A M; Seitz, A; Sekulin, R L; Shellard, R C; Siccama, I; Siegrist, P; Simonetti, S; Simonetto, F; Sissakian, A N; Sitár, B; Skaali, T B; Smadja, G; Smirnov, N; Smirnova, O G; Smith, G R; Sokolov, A; Sosnowski, R; Souza-Santos, D; Spassoff, Tz; Spiriti, E; Squarcia, S; Stanescu, C; Stapnes, Steinar; Stavitski, I; Stepaniak, K; Stichelbaut, F; Stocchi, A; Strauss, J; Strub, R; Stugu, B; Stäck, H; Szczekowski, M; Szeptycka, M; Sánchez, J; Tabarelli de Fatis, T; Tavernet, J P; Tilquin, A; Timmermans, J; Tkatchev, L G; Todorov, T; Toet, D Z; Tomaradze, A G; Tomé, B; Tortora, L; Tranströmer, G; Treille, D; Trischuk, W; Tristram, G; Trombini, A; Troncon, C; Tsirou, A L; Turluer, M L; Tyapkin, I A; Tyndel, M; Tzamarias, S; Ullaland, O; Valenti, G; Vallazza, E; Van Eldik, J; Van der Velde, C; Vassilopoulos, N; Vegni, G; Ventura, L; Venus, W A; Verbeure, F; Verlato, M; Vertogradov, L S; Vilanova, D; Vincent, P; Vitale, L; Vlasov, E; Vodopyanov, A S; Vrba, V; Wahlen, H; Walck, C; Wehr, A; Weierstall, M; Weilhammer, Peter; Wetherell, Alan M; Wicke, D; Wickens, J H; Wielers, M; Wilkinson, G R; Williams, W S C; Winter, M; Witek, M; Woschnagg, K; Yip, K; Yushchenko, O P; Zach, F; Zacharatou-Jarlskog, C; Zaitsev, A; Zalewska-Bak, A; Zalewski, Piotr; Zavrtanik, D; Zevgolatakos, E; Zimin, N I; Zito, M; Zontar, D; Zuberi, R; Zucchelli, G C; Zumerle, G; de Boer, Wim; van Apeldoorn, G W; van Dam, P; Åsman, B; Österberg, K; Überschär, B; Überschär, S

    1995-01-01

    \\def\\tpc{three-particle correlation} \\def\\twopc{two-particle correlation} Measurements are presented of short range three-particle correlations in e^+ e^- annihilations at LEP using data collected by the DELPHI detector. %The jet structure is studied using three-particle correlation functions. At small values of the four-momentum difference, strong three-particle correlations are observed for like-sign (+++ and ---) and for unlike-sign (++- and +--) pion combinations which are not a consequence of two-particle correlations. A possible explanation of the observed effects in like-sign combinations is the existence of higher order Bose-Einstein interference, which significantly changes the particle distributions in jets.

  9. Determination of Chromium Valence Over the Range Cr(0)-Cr(VI) by Electron Energy Loss Spectroscopy

    Science.gov (United States)

    2006-01-01

    be of Cr (VI): Cr (V) [14,40-45] and Cr (IV) [46]. To fully altered by microbes [11-13], green algae [14], higher plants understand the geochemistry of Cr ... Cr (III) by bacteria [42,44,45] and Further, nearly all mineralized Cr in the terrestrial crust is green algae [14], reacts with diphenylcarbazide to...Determination of chromium valence over the range Cr (O)- Cr (VI) by electron energy loss spectroscopy Tyrone L. Daultona , Brenda J. Littleb ’Marine

  10. Effective atomic numbers of polypyrrole via transmission method in the energy range 15.74-40.93 keV

    Energy Technology Data Exchange (ETDEWEB)

    Icelli, Orhan [Department of Physics Education, Education Faculty of Erzincan, Erzincan University, Erzincan (Turkey)], E-mail: orhanicelli@gmail.com; Erzeneoglu, Salih; Saglam, Mustafa [Department of Physics, Faculty of Sciences, Atatuerk University, Erzurum (Turkey)

    2008-03-15

    Effective atomic numbers (Z{sub eff}) of polypyrrole have been determined for total photon interactions in the energy range 15.74-40.93 keV from the accurately measured total attenuation coefficients, for characteristic K and K X-rays of Zr, Mo, Ag, In, Sb, Ba and Pr. The results were compared with the theoretical atomic numbers obtained using the XCOM.

  11. The capabilities and constraints of the LEAP (Long-range Energy Alternatives Planning System) for development of energy matrix; As potencialidades e restricoes do LEAP (Long-range Energy Alternatives Planning System) para o desenvolvimento de matriz energetica

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Afonso Henriques Moreira [MS Consultoria Ltda, Itajuba, MG (Brazil); Universidade Federal de Itajuba (UNIFEI), MG (Brazil); Cruz, Ricardo Alexandre Passos da; Magalhaes, Ricardo Nogueira [IX Consultoria e Representacoes Ltda, Itajuba, MG (Brazil)

    2010-07-01

    This paper seeks to introduce and discuss the main features of the LEAP model preparing energy matrixes, in the medium and long term energy planning context. These characteristics are analyzed and compared to other known simulation models used worldwide, checking potentialities and existing barriers of using the LEAP program (author)

  12. Probing Nucleic Acid Interactions and Pre-mRNA Splicing by Förster Resonance Energy Transfer (FRET Microscopy

    Directory of Open Access Journals (Sweden)

    David Staněk

    2012-11-01

    Full Text Available Förster resonance energy transfer (FRET microscopy is a powerful technique routinely used to monitor interactions between biomolecules. Here, we focus on the techniques that are used for investigating the structure and interactions of nucleic acids (NAs. We present a brief overview of the most commonly used FRET microscopy techniques, their advantages and drawbacks. We list experimental approaches recently used for either in vitro or in vivo studies. Next, we summarize how FRET contributed to the understanding of pre-mRNA splicing and spliceosome assembly.

  13. Estimating protein-protein interaction affinity in single living cells using Förster resonance energy transfer measurements

    DEFF Research Database (Denmark)

    Jensen, Jens Ledet; Raarup, Merete Krog; Rubak, Ege

    Using Förster resonance energy transfer (FRET) images we study the possibility of estimating the equilibrium dissociation constant Kd and the intrinsic FRET efficiency Em from single cells. We model the measurement uncertainty in the acquired images and use the method of total least squares...... for estimation based on the pixel values in the images. Considering a population of cells we demonstrate a variability in the estimates of Kd and Em that cannot be explained by measurement noise and therefore points to systematic variation between images....

  14. High order magnetic optics for high dynamic range proton radiography at a kinetic energy of 800 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Sjue, S. K. L., E-mail: sjue@lanl.gov; Mariam, F. G.; Merrill, F. E.; Morris, C. L.; Saunders, A. [Physics Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2016-01-15

    Flash radiography with 800 MeV kinetic energy protons at Los Alamos National Laboratory is an important experimental tool for investigations of dynamic material behavior driven by high explosives or pulsed power. The extraction of quantitative information about density fields in a dynamic experiment from proton generated images requires a high fidelity model of the proton imaging process. It is shown that accurate calculations of the transmission through the magnetic lens system require terms beyond second order for protons far from the tune energy. The approach used integrates the correlated multiple Coulomb scattering distribution simultaneously over the collimator and the image plane. Comparison with a series of static calibration images demonstrates the model’s accurate reproduction of both the transmission and blur over a wide range of tune energies in an inverse identity lens that consists of four quadrupole electromagnets.

  15. DEIMOS: a beamline dedicated to dichroism measurements in the 350-2500 eV energy range.

    Science.gov (United States)

    Ohresser, P; Otero, E; Choueikani, F; Chen, K; Stanescu, S; Deschamps, F; Moreno, T; Polack, F; Lagarde, B; Daguerre, J-P; Marteau, F; Scheurer, F; Joly, L; Kappler, J-P; Muller, B; Bunau, O; Sainctavit, Ph

    2014-01-01

    The DEIMOS (Dichroism Experimental Installation for Magneto-Optical Spectroscopy) beamline was part of the second phase of the beamline development at French Synchrotron SOLEIL (Source Optimisée de Lumière à Energie Intermédiaire du LURE) and opened to users in March 2011. It delivers polarized soft x-rays to perform x-ray absorption spectroscopy, x-ray magnetic circular dichroism, and x-ray linear dichroism in the energy range 350-2500 eV. The beamline has been optimized for stability and reproducibility in terms of photon flux and photon energy. The main end-station consists in a cryo-magnet with 2 split coils providing a 7 T magnetic field along the beam or 2 T perpendicular to the beam with a controllable temperature on the sample from 370 K down to 1.5 K.

  16. A space crystal diffraction telescope for the energy range of nuclear transitions

    Energy Technology Data Exchange (ETDEWEB)

    von Ballmoos, P.; Naya, J.E.; Albernhe, F.; Vedrenne, G. [Centre d`Etude Spatial des Rayonmenments, Toulouse (France); Smither, R.K.; Faiz, M.; Fernandez, P.; Graber, T. [Argonne National Lab., IL (United States)

    1995-04-01

    This paper contains literature from American Power Conference Air Toxics Being Measured Accurately, Controlled Effectively NO{sub x} and SO{sub 2} Emissions Reduced; Surface Condensers Improve Heat Rate; Usable Fuel from Municipal Solid Waste; Cofiring Technology Reduces Gas Turbine Emissions; Trainable, Rugged Microsensor Identifies of Gases; High-Tc Superconductors Fabricated; High-Temperature Superconducting Current Leads; Vitrification of Low-Level Radioactive and Mixed Wastes; Characterization, Demolition, and Disposal of Contaminated Structures; On-Line Plant Diagnostics and Management; Sulfide Ceramic Materials for Improved Batteries; Flywheel Provides Efficient Energy Storage; Battery Systems for Electric Vehicles; Polymer-Electrolyte Fuel Cells for Transportation; Solid-Oxide Fuel Cells for Transportation; Surface Acoustic Wave Sensor Monitors Emissions in Real-Time; Advance Alternative-Fueled Automotive Technologies; Thermal & Mechanical Process; Flow-Induced Vibration & Flow Distribution in Shell-and-Tube Heat Exchangers; Ice Slurries for District Cooling; Advanced Fluids; Compact Evaporator and Condenser Technology; and Analysis of Failed Nuclear Power Station Components.

  17. Analyses of Alpha-Alpha Elastic Scattering Data in the Energy Range 140 - 280 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Shehadeh, Zuhair F. [Taif University, Taif (Saudi Arabia)

    2017-01-15

    The differential and the reaction cross-sections for 4He-4He elastic scattering data have been nicely obtained at four energies ranging from 140 MeV to 280 MeV (lab system), namely, 140, 160, 198 and 280 MeV, by using a new optical potential with a short-range repulsive core. The treatment has been handled relativistically as υ/c > 0.25 for the two lower energies and υ/c > 0.31 for the two higher ones. In addition to explaining the elastic angular distributions, the adopted potentials accounted for the structure that may exist at angles close to 90◦ , especially for the 198 and the 280-MeV incident energies. No renormalization has been used, and all our potential parameters are new. The necessity of including a short-range repulsive potential term in our real nuclear potential part has been demonstrated. Our results contribute to solving a long-standing problem concerning the nature of the alpha-alpha potential. This is very beneficial in explaining unknown alpha-nucleus and nucleus-nucleus relativistic reactions by using the cluster formalism.

  18. Study of the multi-strange resonance $\\Xi(1530)^{0}$ production with ALICE at the LHC energies

    CERN Document Server

    AUTHOR|(CDS)2080748

    The primary goal of the relativistic heavy-ion physics program at Large Hadron Collider (LHC) at CERN, Geneva, Switzerland is to study the nuclear matter under extreme conditions. The measurement of resonances in ultra-relativistic heavy-ion collisions allows one to study the properties of the hadronic medium. Resonances with short lifetimes compared to the duration of the time span between chemical and kinetic freeze-out are good candidates to prove the interplay of particle re-scattering and regeneration in the hadronic phase, which result in a modification of their measured yields. The ALICE detector and its subsystem used for the analysis presented in this thesis are explained. Particle identification method and a coordinate system of ALICE are provided. Measurements of multi-strange resonance $\\Xi(1530)^{0}$ were performed with the ALICE detector in pp, p-Pb and Pb-Pb collisions at the LHC energies. The ${p_{\\mathrm{T}}}$-spectra of $\\Xi(1530)^{0}$ are obtained and compared with model predictions. The y...

  19. Dynamical effects and time scale in fission processes in nuclear collisions in the Fermi energy range

    Energy Technology Data Exchange (ETDEWEB)

    Colin, J.; Bocage, F.; Louvel, M. [Laboratoire de Physique Corpusculaire, IN2P3-CNRS, ISMRA et Universite, 14 - Caen (France)] [and others

    1999-10-01

    Recent experimental results concerning heavy systems (Pb+Au, Pb+Ag, Pb+Al, Gd+U, Gd+C, Ta+Au, U+U, U+C, Xe+Sn...) obtained at Ganil by the Indra and Nautilus collaborations will be presented. A study of reaction mechanisms has shown the dominant binary and highly dissipative character of the process. The two heavy and excited fragments produced after the first stage of the interaction can experience various decay modes: evaporation, fission, multifragmentation. However, deviations from this simple picture have been found by analysing angular and velocity distribution of light charge particles, IMF's (Intermediate Mass Fragment) and fragments. Indeed, there is an amount of matter in excess emitted in-between the two primary sources suggesting either the existence of a mi-rapidity source similar to the one observed in the relativistic regime (participants) or a strong deformation induced by the dynamics of the collision (neck instability). This last scenario is explored by analysing in details the angular distributions of the fission fragments. More precisely, we observed two components: the first one is isotropic and consistent with the predictions of a statistical model, the second is aligned along the velocity direction of the fissioning nuclei and has to be compared with the predictions of dynamical calculations. In this talk, we present the probability associated to each component as a function of the system size, the charge asymmetry of the fission fragments, the incident energy and the impact parameter. From the statistical component we extract the temperature, the charge and the angular momentum of the fissioning nuclei. From the second component we propose a scenario to explain such process and we discuss the physical parameters which can be extracted. (authors)

  20. On the origin of apparent Z{sub 1}-oscillations in low-energy heavy-ion ranges

    Energy Technology Data Exchange (ETDEWEB)

    Wittmaack, Klaus, E-mail: wittmaack@helmholtz-muenchen.de

    2016-12-01

    It has been known for quite some time that projected ranges measured by Rutherford backscattering spectrometry for a variety of low-energy heavy ions (energy-to-mass ratio E/M{sub 1} less than ∼0.4 keV/u) exhibit significant or even pronounced deviations from the theoretically predicted smooth dependence on the projectile’s atomic number Z{sub 1}. Studied most thoroughly for silicon targets, the effect was attributed to ‘Z{sub 1} oscillations’ in nuclear stopping, in false analogy to the well established Z{sub 1} oscillations in electronic stopping of low-velocity light ions. In this study an attempt was made to get order into range data published by four different groups. To achieve the goal, the absolute values of the ranges from each group had to be (re-)adjusted by up to about ±10%. Adequate justification for this approach is provided. With the changes made, similarities and differences between the different sets of data became much more transparent than before. Very important is the finding that the distortions in heavy-ion ranges are not oscillatory in nature but mostly one-sided, reflecting element-specific transport of implanted atoms deeper into the solid. Exceptions are rare gas and alkali elements, known to exhibit bombardment induced transport towards the surface. Range distortions reported for Xe and Cs could be reproduced on the basis of the recently established rapid relocation model. The extent of transport into the bulk, observed with many other elements, notably noble metals and lanthanides, reflects their high mobility under ion bombardment. The complexity of the element specific transport phenomena became fully evident by also examining the limited number of data available for the apparent range straggling. Profile broadening was identified in several cases. One element (Eu) was found to exhibit profile narrowing. This observation suggests that implanted atoms may agglomerate at peak concentrations up to 2%, possibly a tool for

  1. A closed-form formulation for the build-up factor and absorbed energy for photons and electrons in the Compton energy range in Cartesian geometry

    Energy Technology Data Exchange (ETDEWEB)

    Borges, Volnei; Vilhena, Marco Tullio, E-mail: borges@ufrgs.b, E-mail: vilhena@pq.cnpq.b [Universidade Federal do Rio Grande do Sul (PROMEC/UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia Mecanica; Fernandes, Julio Cesar Lombaldo, E-mail: julio.lombaldo@ufrgs.b [Universidade Federal do Rio Grande do Sul (DMPA/UFRGS), Porto Alegre, RS (Brazil). Dept. de Matematica Pura e Aplicada. Programa de Pos Graduacao em Matematica Aplicada

    2011-07-01

    In this work, we report on a closed-form formulation for the build-up factor and absorbed energy, in one and two dimensional Cartesian geometry for photons and electrons, in the Compton energy range. For the one-dimensional case we use the LTS{sub N} method, assuming the Klein-Nishina scattering kernel for the determination of the angular radiation intensity for photons. We apply the two-dimensional LTS{sub N} nodal solution for the averaged angular radiation evaluation for the two-dimensional case, using the Klein-Nishina kernel for photons and the Compton kernel for electrons. From the angular radiation intensity we construct a closed-form solution for the build-up factor and evaluate the absorbed energy. We present numerical simulations and comparisons against results from the literature. (author)

  2. Electron spin resonance studies of Bi1-xScxFeO3 nanoparticulates: Observation of an enhanced spin canting over a large temperature range

    Science.gov (United States)

    Titus, S.; Balakumar, S.; Sakar, M.; Das, J.; Srinivasu, V. V.

    2017-12-01

    Bi1-xScxFeO3 (x = 0.0, 0.1, 0.15, 0.25) nano particles were synthesized by sol gel method. We then probed the spin system in these nano particles using electron spin resonance technique. Our ESR results strongly suggest the scenario of modified spin canted structures. Spin canting parameter Δg/g as a function of temperature for Scandium doped BFO is qualitatively different from undoped BFO. A broad peak is observed for all the Scandium doped BFO samples and an enhanced spin canting over a large temperature range (75-210 K) in the case of x = 0.15 doping. We also showed that the asymmetry parameter and thereby the magneto-crystalline anisotropy in these BSFO nanoparticles show peaks around 230 K for (x = 0.10 and 0.15) and beyond 300 K for x = 0.25 system. Thus, we established that the Sc doping significantly modifies the spin canting and magneto crystalline anisotropy in the BFO system.

  3. Long Range Surface Plasmon Resonance Based Taper Fiber Optic Sensor with Enhanced Sensitivity using Au Nano-Layer through Radially Polarized Light

    Science.gov (United States)

    Chaurasia, Deepak; Goswami, Nabamita; Saha, Ardhendu

    2017-08-01

    A new theoretical approach towards the sensitivity enhancement of tapered fiber optic sensor based on the long range surface plasmon (LRSP) resonance technique in Teflonmetal coated tapered fiber structure using radially polarized is proposed, designed and simulated within Kretschmann-Raether geometry. The configuration comprising a fiber core coated with 690 nm and 70 nm thin Teflon layer and Au layer respectively where the uniform taper waist having diameter 330 µm and 350 µm with taper ratio of 1.7 (NA: 0.25, 10 mm long waist region) and a sensing layer having varying refractive index from 1.333 to 1.353. With the increase in refractive index the observed results indicates a 1.7 times better sensitive tapered fiber sensor as compared to the existing LRSP based fibre optic sensors using intensity interrogation technique. To the best of our knowledge several articles have been devoted in the field of LRSP based fibre optic sensor with p-polarized light whereas no such article has yet been reported with Teflonused as a dielectric between metal coated taper fiber optic sensors using radially polarized light with better sensitivity. Here sensitivity also analysed w.r.t wavelength interrogation technique where the sensitivity enhancement is about 1.7 times than the existing fiber optic sensors.

  4. Energy harvesting devices, systems, and related methods

    Energy Technology Data Exchange (ETDEWEB)

    Kotter, Dale K.

    2016-10-18

    Energy harvesting devices include a substrate and a plurality of resonance elements coupled to the substrate. Each resonance element is configured to collect energy in the visible and infrared light spectra and to reradiate energy having a wavelength in the range of about 0.8 .mu.m to about 0.9 .mu.m. The resonance elements are arranged in groups of two or more resonance elements. Systems for harvesting electromagnetic radiation include a substrate, a plurality of resonance elements including a conductive material carried by the substrate, and a photovoltaic material coupled to the substrate and to at least one resonance element. The resonance elements are arranged in groups, such as in a dipole, a tripole, or a bowtie configuration. Methods for forming an energy harvesting device include forming groups of two or more discrete resonance elements in a substrate and coupling a photovoltaic material to the groups of discrete resonance elements.

  5. Highly sensitive and selective aptasensor for detection of adenosine based on fluorescence resonance energy transfer from carbon dots to nano-graphite.

    Science.gov (United States)

    Wang, Xu; Xu, Guanhong; Wei, Fangdi; Ma, Yunsu; Ma, Yujie; Song, Yueyue; Cen, Yao; Hu, Qin

    2017-12-15

    In this article, a novel aptasensor was fabricated by modifying carbon dots (CDs) with adenosine aptamer (CDs-aptamer) for sensitive, selective and quantitative detection of adenosine (AD). When nano-graphite (NG) as an energy acceptor was added into the CDs-aptamer (energy donor) solution, the fluorescence of CDs-aptamer was quenched due to fluorescence resonance energy transfer (FRET). When AD was present in the solution of CDs-aptamer/NG, the process of FRET was inhibited because of the specific combination between AD and AD aptamer. As a result, the fluorescence of CDs-aptamer was restored due to the dissociation of CDs-aptamer from NG and its change was proportional to the AD concentration. Under the optimized conditions, a linear range was found to be 2-50nM for the detection of AD with a detection limit of 0.63nM. Furthermore, the application of the proposed approach was demonstrated in real sample with satisfying results and it showed promise in diagnostic purpose. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. A simple method analyzing 2H nuclear magnetic resonance line shapes to determine the activation energy distribution of mobile guest molecules in disordered systems

    Science.gov (United States)

    Rössler, E.; Taupitz, M.; Börner, K.; Schulz, M.; Vieth, H.-M.

    1990-05-01

    We investigated the 2H nuclear magnetic resonance (NMR) line shape of deuterated benzene and hexamethylbenzene as guest molecules in organic glasses in the temperature range of 10-150 K. A broad distribution G(ln τ) of correlation times determines the slowing down of the molecular reorientation around the sixfold symmetry axis of the guests. The line shape is described by a superposition of temperature-dependent fractions F(T) of only two subspectra corresponding to fast and slowly rotating molecules; no spectra characteristic for intermediate mobility as found in crystal matrices are observed. Assuming a thermally activated motional process, the temperature dependence of G(ln τ) comes from a temperature-independent distribution of activation energies g(E). In this case, the derivative of the fraction dF(T)/dT yields directly the distribution g(E). Using this method an asymmetric distribution g(E) with its maximum at the low energy side is found for the glasses. While the general shape of g(E) is similar for different matrices, the mean activation energy differs significantly. We used the same approach to discuss similar ``two-phase'' spectra for the isotropic reorientation of toluene in polystyrene below the glass transition of the mixed system. Here, an alternative explanation is offered considering a distribution of glass transition points Tg for the dynamics of toluene in the mixed system.

  7. Interplay of short-range correlations and nuclear symmetry energy in hard-photon production from heavy-ion reactions at Fermi energies

    Science.gov (United States)

    Yong, Gao-Chan; Li, Bao-An

    2017-12-01

    Within an isospin- and momentum-dependent transport model for nuclear reactions at intermediate energies, we investigate the interplay of the nucleon-nucleon short-range correlations (SRCs) and nuclear symmetry energy Esym(ρ ) on hard-photon spectra in collisions of several Ca isotopes on 112Sn and 124Sn targets at a beam energy of 45 MeV/nucleon. It is found that over the whole spectra of hard photons studied, effects of the SRCs overwhelm those owing to the Esym(ρ ) . The energetic photons come mostly from the high-momentum tails (HMTs) of single-nucleon momentum distributions in the target and projectile. Within the neutron-proton dominance model of SRCs based on the consideration that the tensor force acts mostly in the isosinglet and spin-triplet nucleon-nucleon interaction channel, there are equal numbers of neutrons and protons, thus a zero isospin asymmetry in the HMTs. Therefore, experimental measurements of the energetic photons from heavy-ion collisions at Fermi energies have the great potential to help us better understand the nature of SRCs without any appreciable influence by the uncertain Esym(ρ ) . These measurements will be complementary to but also have some advantages over the ongoing and planned experiments using hadronic messengers from reactions induced by high-energy electrons or protons. Because the underlying physics of SRCs and Esym(ρ ) are closely correlated, a better understanding of the SRCs will, in turn, help constrain the nuclear symmetry energy more precisely in a broad density range.

  8. Förster resonance energy transfer: Role of diffusion of fluorophore orientation and separation in observed shifts of FRET efficiency.

    Directory of Open Access Journals (Sweden)

    Bram Wallace

    Full Text Available Förster resonance energy transfer (FRET is a widely used single-molecule technique for measuring nanoscale distances from changes in the non-radiative transfer of energy between donor and acceptor fluorophores. For macromolecules and complexes this observed transfer efficiency is used to infer changes in molecular conformation under differing experimental conditions. However, sometimes shifts are observed in the FRET efficiency even when there is strong experimental evidence that the molecular conformational state is unchanged. We investigate ways in which such discrepancies can arise from kinetic effects. We show that significant shifts can arise from the interplay between excitation kinetics, orientation diffusion of fluorophores, separation diffusion of fluorophores, and non-emitting quenching.

  9. In Vivo Interaction Studies by Measuring Förster Resonance Energy Transfer Through Fluorescence Lifetime Imaging Microscopy (FRET/FLIM).

    Science.gov (United States)

    Fäßler, Florian; Pimpl, Peter

    2017-01-01

    Combinations of multiple fluorescent fusion proteins are commonly generated and used for colocalization studies in live cell imaging but also biochemical analysis of protein-protein interactions by co-immunoprecipitation in vitro. Advanced microscopy techniques like Förster resonance energy transfer through fluorescence lifetime imaging microscopy (FRET/FLIM) nowadays enable the combination of both approaches. This opens up the possibility to perform a location-specific protein-protein interaction analysis in vivo. To this end, the nonradiant energy transfer from a donor to an acceptor fluorophore (FRET) is harnessed to test for close proximity as an indicator for interaction, while the spectromicroscopical measurement of the fluorescence lifetime by FLIM serves as a readout.Here, we describe FRET/FLIM measurements performed with a Leica TCS SP8/PicoHarp 300 combination to demonstrate the interaction between a RFP-tagged GFP-nanobody and its epitope, GFP, in the cytoplasm of tobacco mesophyll protoplasts.

  10. Probing intermolecular protein-protein interactions in the calcium-sensing receptor homodimer using bioluminescence resonance energy transfer (BRET)

    DEFF Research Database (Denmark)

    Jensen, Anders A.; Hansen, Jakob L; Sheikh, Søren P

    2002-01-01

    The calcium-sensing receptor (CaR) belongs to family C of the G-protein coupled receptor superfamily. The receptor is believed to exist as a homodimer due to covalent and non-covalent interactions between the two amino terminal domains (ATDs). It is well established that agonist binding to family C......-induced intermolecular movements in the CaR homodimer using the new bioluminescence resonance energy transfer technique, BRET2, which is based on the transference of energy from Renilla luciferase (Rluc) to the green fluorescent protein mutant GFP2. We tagged CaR with Rluc and GFP2 at different intracellular locations....... Stable and highly receptor-specific BRET signals were obtained in tsA cells transfected with Rluc- and GFP2-tagged CaRs under basal conditions, indicating that CaR is constitutively dimerized. However, the signals were not enhanced by the presence of agonist. These results could indicate that at least...

  11. Förster resonance energy transfer enhanced color-conversion using colloidal semiconductor quantum dots for solid state lighting

    Science.gov (United States)

    Nizamoglu, Sedat; Demir, Hilmi Volkan

    2009-10-01

    In this paper, we present Förster resonance energy transfer (FRET)-enhanced color-conversion using colloidal semiconductor quantum dot nanocrystals (NCs) to make reddish-orange light-emitting diodes for use in ultraefficient solid state lighting. To achieve FRET enhancement at 614 nm, we use an energy gradient hybrid structure made of cyan- and orange-emitting CdSe/ZnS NCs (λPL=492 and 588 nm in solution, respectively). This enables recycling of trapped excitons using FRET and achieves a relative quantum efficiency enhancement of 15.1% in reddish-orange full color-conversion for the integrated hybrid cyan-orange NC layer with respect to the case of full color-conversion using only orange NCs without FRET.

  12. Graphene and graphene-like two-denominational materials based fluorescence resonance energy transfer (FRET) assays for biological applications.

    Science.gov (United States)

    Tian, Feng; Lyu, Jing; Shi, Jingyu; Yang, Mo

    2017-03-15

    In the past decades, Förster resonance energy transfer (FRET) has been applied in many biological applications to reveal the biological information at the nanoscale. Recently, graphene and graphene-like two-dimensional (2D) nanomaterials started to be used in FRET assays as donors or acceptors including graphene oxide (GO), graphene quantum dot (GQD), graphitic-carbon nitride nanosheets (g-C3N4) and transition metal dichalcogenides (e.g. MoS2, MnO2, and WS2). Due to the remarkable properties such as large surface to volume ratio, tunable energy band, photoluminescence and excellent biocompatibility, these 2D nanomaterials based FRET assays have shown great potential in various biological applications. This review summarizes the recent development of graphene and graphene-like 2D nanomaterials based FRET assays in applications of biosensing, bioimaging, and drug delivery monitoring. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Nanohole-based surface plasmon resonance instruments with improved spectral resolution quantify a broad range of antibody-ligand binding kinetics.

    Science.gov (United States)

    Im, Hyungsoon; Sutherland, Jamie N; Maynard, Jennifer A; Oh, Sang-Hyun

    2012-02-21

    We demonstrate an affordable low-noise surface plasmon resonance (SPR) instrument based on extraordinary optical transmission (EOT) in metallic nanohole arrays and quantify a broad range of antibody-ligand binding kinetics with equilibrium dissociation constants ranging from 200 pM to 40 nM. This nanohole-based SPR instrument is straightforward to construct, align, and operate, since it is built around a standard microscope and a portable fiber-optic spectrometer. The measured refractive index resolution of this platform is 3.1 × 10(-6) without on-chip cooling, which is among the lowest reported for SPR sensors based on EOT. This is accomplished via rapid full-spectrum acquisition in 10 ms followed by frame averaging of the EOT spectra, which is made possible by the production of template-stripped gold nanohole arrays with homogeneous optical properties over centimeter-sized areas. Sequential SPR measurements are performed using a 12-channel microfluidic flow cell after optimizing surface modification protocols and antibody injection conditions to minimize mass-transport artifacts. The immobilization of a model ligand, the protective antigen of anthrax on the gold surface, is monitored in real-time with a signal-to-noise ratio of ~860. Subsequently, real-time binding kinetic curves were measured quantitatively between the antigen and a panel of small, 25 kDa single-chain antibodies at concentrations down to 1 nM. These results indicate that nanohole-based SPR instruments have potential for quantitative antibody screening and as a general-purpose platform for integrating SPR sensors with other bioanalytical tools.

  14. Short- and long-range energy strategies for Japan and the world after the Fukushima nuclear accident

    Science.gov (United States)

    Muraoka, K.; Wagner, F.; Yamagata, Y.; Donné, A. J. H.

    2016-01-01

    The accident at the Fukushima Dai-ichi nuclear power station in 2011 has caused profound effects on energy policies in Japan and worldwide. This is particularly because it occurred at the time of the growing awareness of global warming forcing measures towards decarbonised energy production, namely the use of fossil fuels has to be drastically reduced from the present level of more than 80% by 2050. A dilemma has now emerged because nuclear power, a CO2-free technology with proven large-scale energy production capability, lost confidence in many societies, especially in Japan and Germany. As a consequence, there is a world-wide effort now to expand renewable energies (REs), specifically photo-voltaic (PV) and wind power. However, the authors conjecture that PV and wind power can provide only up to a 40% share of the electricity production as long as sufficient storage is not available. Beyond this level, the technological (high grid power) and economic problems (large surplus production) grow. This is the result of the analysis of the growing use of REs in the electricity systems for Germany and Japan. The key element to overcome this situation is to develop suitable energy storage technologies. This is particularly necessary when electricity will become the main energy source because also transportation, process heat and heating, will be supplied by it. Facing the difficulty in replacing all fossil fuels in all countries with different technology standards, a rapid development of carbon capture and storage (CCS) might also be necessary. Therefore, for the short-range strategy up to 2050, all meaningful options have to be developed. For the long-range strategy beyond 2050, new energy sources (such as thermonuclear fusion, solar fuels and nuclear power—if inherently safe concepts will gain credibility of societies again), and large-scale energy storage systems based on novel concepts (such as large-capacity batteries and hydrogen) is required. It is acknowledged

  15. Wind Induced Vibration Control and Energy Harvesting of Electromagnetic Resonant Shunt Tuned Mass-Damper-Inerter for Building Structures

    Directory of Open Access Journals (Sweden)

    Yifan Luo

    2017-01-01

    Full Text Available This paper proposes a novel inerter-based dynamic vibration absorber, namely, electromagnetic resonant shunt tuned mass-damper-inerter (ERS-TMDI. To obtain the performances of the ERS-TMDI, the combined ERS-TMDI and a single degree of freedom system are introduced. H2 criteria performances of the ERS-TMDI are introduced in comparison with the classical tuned mass-damper (TMD, the electromagnetic resonant shunt series TMDs (ERS-TMDs, and series-type double-mass TMDs with the aim to minimize structure damage and simultaneously harvest energy under random wind excitation. The closed form solutions, including the mechanical tuning ratio, the electrical damping ratio, the electrical tuning ratio, and the electromagnetic mechanical coupling coefficient, are obtained. It is shown that the ERS-TMDI is superior to the classical TMD, ERS-TMDs, and series-type double-mass TMDs systems for protection from structure damage. Meanwhile, in the time domain, a case study of Taipei 101 tower is presented to demonstrate the dual functions of vibration suppression and energy harvesting based on the simulation fluctuating wind series, which is generated by the inverse fast Fourier transform method. The effectiveness and robustness of ERS-TMDI in the frequency and time domain are illustrated.

  16. A reduced graphene oxide-based fluorescence resonance energy transfer sensor for highly sensitive detection of matrix metalloproteinase 2.

    Science.gov (United States)

    Xi, Gaina; Wang, Xiaoping; Chen, Tongsheng

    2016-01-01

    A novel fluorescence nanoprobe (reduced nano-graphene oxide [nrGO]/fluorescein isothiocyanate-labeled peptide [Pep-FITC]) for ultrasensitive detection of matrix metalloproteinase 2 (MMP2) has been developed by engineering the Pep-FITC comprising the specific MMP2 substrate domain (PLGVR) onto the surface of nrGO particles through non-covalent linkage. The nrGO was obtained by water bathing nano-graphene oxide under 90°C for 4 hours. After mixing the nrGO and Pep-FITC for 30 seconds, the fluorescence from Pep-FITC was almost completely quenched due to the fluorescence resonance energy transfer between fluorescein isothiocyanate (FITC) and nrGO. Upon cleavage of the amide bond between Leu and Gly in the Pep-FITC by protease-MMP2, the FITC bound to nrGO was separated from nrGO surface, disrupting the fluorescence resonance energy transfer process and resulting in fluorescence recovery of FITC. Under optimal conditions, the fluorescence recovery of nrGO/Pep-FITC was found to be directly proportional to the concentration of MMP2 within 0.02-0.1 nM. The detection limit of the nrGO/Pep-FITC was determined to be 3 pM, which is approximately tenfold lower than that of the unreduced carboxylated nano-graphene oxide/Pep-FITC probe.

  17. On the dispersion management of fluorite whispering-gallery mode resonators for Kerr optical frequency comb generation in the telecom and mid-infrared range

    CERN Document Server

    Lin, Guoping

    2015-01-01

    Optical whispering gallery mode (WGM) resonators have been very attracting platforms for versatile Kerr frequency comb generations. We report a systematic study on the material dispersion of various optical materials that are capable of supporting quality factors above $10^9$. Using an analytical approximation of WGM resonant frequencies in disk resonators, we investigate the effect of the geometry and transverse mode order on the total group-velocity dispersion ($GVD$). We demonstrate that the major radii and the radial mode indices play an important role in tailoring the $GVD$ of WGM resonators. In particular, our study shows that in WGM disk-resonators, the polar families of modes have very similar $GVD$, while the radial families of modes feature dispersion values that can differ by up to several orders of magnitude. The effect of these giant dispersion shifts are experimentally evidenced in Kerr comb generation with magnesium fluoride. From a more general perspective, this critical feature enables to pus...

  18. Contrasting accounts of direction and shape perception in short-range motion: Counterchange compared with motion energy detection.

    Science.gov (United States)

    Norman, Joseph; Hock, Howard; Schöner, Gregor

    2014-07-01

    It has long been thought (e.g., Cavanagh & Mather, 1989) that first-order motion-energy extraction via space-time comparator-type models (e.g., the elaborated Reichardt detector) is sufficient to account for human performance in the short-range motion paradigm (Braddick, 1974), including the perception of reverse-phi motion when the luminance polarity of the visual elements is inverted during successive frames. Human observers' ability to discriminate motion direction and use coherent motion information to segregate a region of a random cinematogram and determine its shape was tested; they performed better in the same-, as compared with the inverted-, polarity condition. Computational analyses of short-range motion perception based on the elaborated Reichardt motion energy detector (van Santen & Sperling, 1985) predict, incorrectly, that symmetrical results will be obtained for the same- and inverted-polarity conditions. In contrast, the counterchange detector (Hock, Schöner, & Gilroy, 2009) predicts an asymmetry quite similar to that of human observers in both motion direction and shape discrimination. The further advantage of counterchange, as compared with motion energy, detection for the perception of spatial shape- and depth-from-motion is discussed.

  19. Experimental study of high energy electron interactions in a superconducting aluminum alloy resonant bar

    CERN Document Server

    Barucci, M; Buonomo, B; Cavallari, G; Coccia, E; D'Antonio, S; Fafone, V; Ligi, C; Lolli, L; Marini, A; Mazzitelli, G; Modestino, G; Pizzella, G; Quintieri, L; Risegari, L; Rocchi, A; Ronga, F; Valente, P; Ventura, G; Vinko, S M

    2009-01-01

    Peak amplitude measurements of the fundamental mode of oscillation of a suspended aluminum alloy bar hit by an electron beam show that the amplitude is enhanced by a factor ~3.5 when the material is in the superconducting state. This result is consistent with the cosmic ray observations made by the resonant gravitational wave detector NAUTILUS, made of the same alloy, when operated in the superconducting state. A comparison of the experimental data with the predictions of the model describing the underlying physical process is also presented.

  20. High accuracy 234U(n,f cross section in the resonance energy region

    Directory of Open Access Journals (Sweden)

    Leal-Cidoncha E.

    2017-01-01

    Full Text Available New results are presented of the 234U neutron-induced fission cross section, obtained with high accuracy in the resonance region by means of two methods using the 235U(n,f as reference. The recent evaluation of the 235U(n,f obtained with SAMMY by L. C. Leal et al. (these Proceedings, based on previous n_TOF data [1], has been used to calculate the 234U(n,f cross section through the 234U/235U ratio, being here compared with the results obtained by using the n_TOF neutron flux.

  1. High accuracy 234U(n,f) cross section in the resonance energy region

    Science.gov (United States)

    Leal-Cidoncha, E.; Durán, I.; Paradela, C.; Tassan-Got, L.; Audouin, L.; Leal, L. C.; Naour, C. Le; Noguere, G.; Tarrío, D.; Leong, L. S.; Altstadt, S.; Andrzejewski, J.; Barbagallo, M.; Bécares, V.; Bečvář, F.; Belloni, F.; Berthoumieux, E.; Billowes, J.; Boccone, V.; Bosnar, D.; Brugger, M.; Calviani, M.; Calviño, F.; Cano-Ott, D.; Carrapiço, C.; Cerutti, F.; Chiaveri, E.; Chin, M.; Colonna, N.; Cortés, G.; Cortés-Giraldo, M. A.; Diakaki, M.; Domingo-Pardo, C.; Dressler, R.; Eleftheriadis, C.; Ferrari, A.; Fraval, K.; Ganesan, S.; García, A. R.; Giubrone, G.; Gómez-Hornillos, M. B.; Gonçalves, I. F.; González-Romero, E.; Griesmayer, E.; Guerrero, C.; Gunsing, F.; Gurusamy, P.; Hernández-Prieto, A.; Jenkins, D. G.; Jericha, E.; Kadi, Y.; Käppeler, F.; Karadimos, D.; Kivel, N.; Kokkoris, M.; Krtička, M.; Kroll, J.; Lampoudis, C.; Langer, C.; Lederer, C.; Leeb, H.; Losito, R.; Mallick, A.; Manousos, A.; Marganiec, J.; Martínez, T.; Massimi, C.; Mastinu, P. F.; Mastromarco, M.; Meaze, M.; Mendoza, E.; Mengoni, A.; Milazzo, P. M.; Mingrone, F.; Mirea, M.; Mondelaers, W.; Pavlik, A.; Perkowski, J.; Plompen, A.; Praena, J.; Quesada, J. M.; Rauscher, T.; Reifarth, R.; Riego, A.; Robles, M. S.; Roman, F.; Rubbia, C.; Sabaté-Gilarte, M.; Sarmento, R.; Saxena, A.; Schillebeeckx, P.; Schmidt, S.; Schumann, D.; Tagliente, G.; Tain, J. L.; Tsinganis, A.; Valenta, S.; Vannini, G.; Variale, V.; Vaz, P.; Ventura, A.; Versaci, R.; Vermeulen, M. J.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Ware, T.; Weigand, M.; Weiß, C.; Wright, T.; Žugec, P.

    2017-09-01

    New results are presented of the 234U neutron-induced fission cross section, obtained with high accuracy in the resonance region by means of two methods using the 235U(n,f) as reference. The recent evaluation of the 235U(n,f) obtained with SAMMY by L. C. Leal et al. (these Proceedings), based on previous n_TOF data [1], has been used to calculate the 234U(n,f) cross section through the 234U/235U ratio, being here compared with the results obtained by using the n_TOF neutron flux.

  2. Nontrivial Effect of the Color-Exchange of a Donor/Acceptor Pair in the Engineering of Förster Resonance Energy Transfer (FRET)-Based Indicators.

    Science.gov (United States)

    Ohta, Yusaku; Kamagata, Takanori; Mukai, Asuka; Takada, Shinji; Nagai, Takeharu; Horikawa, Kazuki

    2016-07-15

    Genetically encoded indicators driven by the Förster resonance energy transfer (FRET) mechanism are reliable tools for live imaging. While the properties of FRET-based indicators have been improved over the years, they often suffer from a poor dynamic range due to the lack of comprehensive understanding about how to apply an appropriate strategy to optimize the FRET parameters. One of the most successful optimizations is the incorporation of circularly permuted fluorescent proteins (cpFPs). To better understand the effects of this strategy, we systematically investigated the properties of the indicators by utilizing a set of FRET backbones consisting of native or one of the most effective cp variants (cp173FPs) with considerations of their order. As a result, the ordering of donor and acceptor FPs, which has been ignored in previous studies, was found to significantly affect the dynamic range of indicators. By utilizing these backbones, we succeeded in improving a cGMP indicator with 3.6-fold increased dynamic range and in generating an ultrasensitive cAMP indicator capable of environmental imaging, demonstrating the practical importance of the ordering of donors and acceptors in the engineering of FRET-based indicators.

  3. Energy distributions of neutral species ejected from well-characterized surfaces measured by means of multiphoton resonance ionization spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, D.; Ishigami, R.; Dhole, S.D.; Morita, K. E-mail: k-morita@mail.nucl.nagoya-u.ac.jp

    2000-04-01

    The energy distributions of neutral atoms ejected from the polycrystalline Cu target, the Si(1 1 1)-7x7 surface, and the Si(1 1 1)-''5 x 5''-Cu surface by 5 keV Ar{sup +} ion bombardment have been measured with very high efficiency by means of the multi-photon resonance ionization spectroscopy, in order to obtain the surface binding energies. The energy distributions for Cu from polycrystalline Cu target, Si from the Si(1 1 1)-7x7 surface, and Cu from the Si(1 1 1)-''5 x 5''-Cu surface have been found to have a peak at energies of around 3.0, 5.0 and 1.5 eV, and the function shapes of high energy tails to be proportional to E{sup -1.9}, E{sup -1.2} and E{sup -1.3}, respectively. Based on the linear collision cascade theory, the surface binding energies are determined to be 5.7, 6.0 and 2.0 eV, and the power factor m in the power law approximation to the Thomas-Fermi potential are determined to be 0.1, 0.4 and 0.3 for Cu from the Cu polycrystalline, Si from the Si(1 1 1)-7x7 surface, and Cu from the Si(1 1 1)-''5 x 5''-Cu surface, respectively. In conclusion, the results indicate that the energy distributions of ejected particles are well characterized by the linear collision cascade theory developed by Sigmund.

  4. Critical coupling and coherent perfect absorption for ranges of energies due to a complex gain and loss symmetric system

    Energy Technology Data Exchange (ETDEWEB)

    Hasan, Mohammad, E-mail: mohammadhasan786@gmail.com [ISRO Satellite Centre (ISAC), Bangalore-560017 (India); Ghatak, Ananya, E-mail: gananya04@gmail.com [Department of Physics, Banaras Hindu University, Varanasi-221005 (India); Mandal, Bhabani Prasad, E-mail: bhabani.mandal@gmail.com [Department of Physics, Banaras Hindu University, Varanasi-221005 (India)

    2014-05-15

    We consider a non-Hermitian medium with a gain and loss symmetric, exponentially damped potential distribution to demonstrate different scattering features analytically. The condition for critical coupling (CC) for unidirectional wave and coherent perfect absorption (CPA) for bidirectional waves are obtained analytically for this system. The energy points at which total absorption occurs are shown to be the spectral singular points for the time reversed system. The possible energies at which CC occurs for left and right incidence are different. We further obtain periodic intervals with increasing periodicity of energy for CC and CPA to occur in this system. -- Highlights: •Energy ranges for CC and CPA are obtained explicitly for complex WS potential. •Analytical conditions for CC and CPA for PT symmetric WS potential are obtained. •Conditions for left and right CC are shown to be different. •Conditions for CC and CPA are shown to be that of SS for the time reversed system. •Our model shows the great flexibility of frequencies for CC and CPA.

  5. Study of the 2H(p,γ)3He reaction in the Big Bang Nucleosynthesis energy range at LUNA

    Science.gov (United States)

    Mossa, Viviana

    2018-01-01

    Deuterium is the first nucleus produced in the Universe, whose accumulation marks the beginning of the so called Big Bang Nucleosynthesis (BBN). Its primordial abundance is very sensitive to some cosmological parameters like the baryon density and the number of the neutrino families. Presently the main obstacle to an accurate theoretical deuterium abundance evaluation is due to the poor knowledge of the 2H(p,γ)3He cross section at BBN energies. The aim of the present work is to describe the experimental approach proposed by the LUNA collaboration, whose goal is to measure, with unprecedented precision, the total and the differential cross section of the reaction in the 30 < Ec.m. [keV] < 300 energy range.

  6. Characterization of extended range Bonner Sphere Spectrometers in the CERF high-energy broad neutron field at CERN

    Science.gov (United States)

    Agosteo, S.; Bedogni, R.; Caresana, M.; Charitonidis, N.; Chiti, M.; Esposito, A.; Ferrarini, M.; Severino, C.; Silari, M.

    2012-12-01

    The accurate determination of the ambient dose equivalent in the mixed neutron-photon fields encountered around high-energy particle accelerators still represents a challenging task. The main complexity arises from the extreme variability of the neutron energy, which spans over 10 orders of magnitude or more. Operational survey instruments, which response function attempts to mimic the fluence-to-ambient dose equivalent conversion coefficient up to GeV neutrons, are available on the market, but their response is not fully reliable over the entire energy range. Extended range rem counters (ERRC) do not require the exact knowledge of the energy distribution of the neutron field and the calibration can be done with a source spectrum. If the actual neutron field has an energy distribution different from the calibration spectrum, the measurement is affected by an added uncertainty related to the partial overlap of the fluence-to-ambient dose equivalent conversion curve and the response function. For this reason their operational use should always be preceded by an "in-field" calibration, i.e. a calibration made against a reference instrument exposed in the same field where the survey-meter will be employed. In practice the extended-range Bonner Sphere Spectrometer (ERBSS) is the only device which can serve as reference instrument in these fields, because of its wide energy range and the possibility to assess the neutron fluence and the ambient dose equivalent (H*(10)) values with the appropriate accuracy. Nevertheless, the experience gained by a number of experimental groups suggests that mandatory conditions for obtaining accurate results in workplaces are: (1) the use of a well-established response matrix, thus implying validation campaigns in reference monochromatic neutrons fields, (2) the expert and critical use of suitable unfolding codes, and (3) the performance test of the whole system (experimental set-up, elaboration and unfolding procedures) in a well

  7. First operational experience with the LHC machine protection system when operating with beam energies beyond the 100MJ range

    CERN Document Server

    Assmann, R; Ferro-Luzzi, M; Goddard, B; Lamont, M; Schmidt, R; Siemko, A; Uythoven, J; Wenninger, J; Zerlauth, M

    2012-01-01

    The Large Hadron Collider (LHC) at CERN has made remarkable progress during 2011, surpassing its ambitious goal for the year in terms of luminosity delivered to the LHC experiments. This achievement was made possible by a progressive increase of beam intensities by more than 5 orders of magnitude during the first months of operation, reaching stored beam energies beyond the 100MJ range at the end of the year, less than a factor of 4 from the nominal design value. The correct functioning of the machine protection systems is vital during the different operational phases, for initial operation and even more when approaching nominal beam parameters where already a small fraction of the stored energy is sufficient to damage accelerator equipment or experiments in case of uncontrolled beam loss. Safe operation of the machine in presence of such high intensity proton beams is guaranteed by the interplay of many different systems: beam dumping system, beam interlocks, beam instrumentation, equipment monitoring, colli...

  8. Solid-state effects on thermal-neutron cross sections and on low-energy resonances

    Energy Technology Data Exchange (ETDEWEB)

    Harvey, J.A.; Mook, H.A.; Hill, N.W.; Shahal, O.

    1982-01-01

    The neutron total cross sections of several single crystals (Si, Cu, sapphire), several polycrystalline samples (Cu, Fe, Be, C, Bi, Ta), and a fine-powder copper sample have been measured from 0.002 to 5 eV. The Cu powder and polycrystalline Fe, Be and C data exhibit the expected abrupt changes in cross section. The cross section of the single crystal of Si is smooth with only small broad fluctuations. The data on two single Cu crystals, the sapphire crystal, cast Bi, and rolled samples of Ta and Cu have many narrow peaks approx. 10/sup -3/ eV wide. High resolution (0.3%) transmission measurements were made on the 1.057-eV resonance in /sup 240/Pu and the 0.433-eV resonance in /sup 180/Ta, both at room and low temperatures to study the effects of crystal binding. Although the changes in Doppler broadening with temperature were apparent, no asymmetries due to a recoilless contribution were observed.

  9. A Framework to Analyze the Stochastic Harmonics and Resonance of Wind Energy Grid Interconnection

    Directory of Open Access Journals (Sweden)

    Youngho Cho

    2016-08-01

    Full Text Available This paper addresses a modeling and analysis methodology for investigating the stochastic harmonics and resonance concerns of wind power plants (WPPs. Wideband harmonics from modern wind turbines (WTs are observed to be stochastic, associated with real power production, and they may adversely interact with the grid impedance and cause unexpected harmonic resonance, if not comprehensively addressed in the planning and commissioning of the WPPs. These issues should become more critical as wind penetration levels increase. We thus propose a planning study framework comprising the following functional steps: First, the best fitted probability density functions (PDFs of the harmonic components of interest in the frequency domain are determined. In operations planning, maximum likelihood estimations (MLEs followed by a chi-square test are used once field measurements or manufacturers’ data are available. Second, harmonic currents from the WPP are represented by randomly-generating harmonic components based on their PDFs (frequency spectrum and then synthesized for time domain simulations via inverse Fourier transform. Finally, we conduct a comprehensive assessment by including the impacts of feeder configurations, harmonic filters and the variability of parameters. We demonstrate the efficacy of the proposed study approach for a 100-MW offshore WPP consisting of 20 units of 5-MW full converter turbines, a realistic benchmark system adapted from a WPP under development in Korea and discuss lessons learned through this research.

  10. Blueshift of the surface plasmon resonance in silver nanoparticles studied with EELS

    DEFF Research Database (Denmark)

    Raza, Søren; Stenger, Nicolas; Kadkhodazadeh, Shima

    2013-01-01

    We study the surface plasmon (SP) resonance energy of isolated spherical Ag nanoparticles dispersed on a silicon nitride substrate in the diameter range 3.5–26 nm with monochromated electron energy-loss spectroscopy. A significant blueshift of the SP resonance energy of 0.5 eV is measured when...

  11. 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...

  12. Proposal of a New Method for Measuring Förster Resonance Energy Transfer (FRET Rapidly, Quantitatively and Non-Destructively

    Directory of Open Access Journals (Sweden)

    Paul Johannes Helm

    2012-09-01

    Full Text Available The process of radiationless energy transfer from a chromophore in an excited electronic state (the “donor” to another chromophore (an “acceptor”, in which the energy released by the donor effects an electronic transition, is known as “Förster Resonance Energy Transfer” (FRET. The rate of energy transfer is dependent on the sixth power of the distance between donor and acceptor. Determining FRET efficiencies is tantamount to measuring distances between molecules. A new method is proposed for determining FRET efficiencies rapidly, quantitatively, and non-destructively on ensembles containing donor acceptor pairs: at wavelengths suitable for mutually exclusive excitations of donors and acceptors, two laser beams are intensity-modulated in rectangular patterns at duty cycle ½ and frequencies ƒ1 and ƒ2 by electro-optic modulators. In an ensemble exposed to these laser beams, the donor excitation is modulated at ƒ1, and the acceptor excitation, and therefore the degree of saturation of the excited electronic state of the acceptors, is modulated at ƒ2. Since the ensemble contains donor acceptor pairs engaged in FRET, the released donor fluorescence is modulated not only at ƒ1 but also at the beat frequency Δƒ: = |ƒ1 − ƒ2|. The depth of the latter modulation, detectable via a lock-in amplifier, quantitatively indicates the FRET efficiency.

  13. Activation cross-sections of proton induced reactions on vanadium in the 37-65 MeV energy range

    OpenAIRE

    Ditrói, F.; Tárkányi, F.; Takács, S.; Hermanne, A.

    2016-01-01

    Experimental excitation functions for proton induced reactions on natural vanadium in the 37-65 MeV energy range were measured with the activation method using a stacked foil irradiation technique. By using high resolution gamma spectrometry cross-section data for the production of $^{51,48}$Cr, $^{48}$V, $^{48,47,46,44m,44g,43}$Sc and $^{43,42}$K were determined. Comparisons with the earlier published data are presented and results predicted by different theoretical codes (EMPIRE and TALYS) ...

  14. Detection of Parametric Roll Resonance on Ships from Indication of Nonlinear Energy Flow

    DEFF Research Database (Denmark)

    Galeazzi, Roberto; Blanke, Mogens; Poulsen, Niels Kjølstad

    2009-01-01

    the roll oscillations are about 5◦. This paper proposes two different detection approaches: the first one based on sinusoidal detection in white gaussian noise; the second one utilizes an energy flow indicator in order to catch the onset of parametric roll based upon the transfer of energy from heave...... and pitch to roll. Both detectors have been validated against experimental data of a scale model of a container vessel excited with both regular and irregular waves. The detector based on the energy flow indicator proved to be very robust to different scenarios (regular/irregular waves) since it does...

  15. SINGLE- AND TWO-COMPONENT GAMMA-RAY BURST SPECTRA IN THE FERMI GBM-LAT ENERGY RANGE

    Energy Technology Data Exchange (ETDEWEB)

    Veres, P.; Meszaros, P., E-mail: veresp@psu.edu, E-mail: nnp@astro.psu.edu [Department of Astronomy and Astrophysics, Department of Physics, and Center for Particle Astrophysics, 525 Davey Lab., Pennsylvania State University, University Park, PA 16802 (United States)

    2012-08-10

    Most Fermi gamma-ray burst spectra appear as either a broken power law extending to GeV energies or as a broken power with a separate GeV power-law component. Here we show that such spectra can be understood in terms of magnetically dominated relativistic jets where a dissipative photosphere produces the prompt MeV emission, which is extended into the GeV range by inverse Compton scattering in the external shock, with possible contributions from a reverse shock as well. The bulk Lorentz factors required in these models are in the range of 300-600, and the MeV-GeV time delays arise naturally. In some cases an optical flash and a sub-dominant thermal component are also present.

  16. A novel upconversion, fluorescence resonance energy transfer biosensor (FRET) for sensitive detection of lead ions in human serum

    Science.gov (United States)

    Xu, Sai; Xu, Shihan; Zhu, Yongsheng; Xu, Wen; Zhou, Pingwei; Zhou, Chunyang; Dong, Biao; Song, Hongwei

    2014-10-01

    There has been great progress in the development of fluorescence biosensors based on quantum dots (QDs) for the detection of lead ions. However, most methods are detecting lead ions in aqueous solution rather than in human serum due to the influence of protein autofluorescence in serum excited by visible light. Thus, we developed a novel fluorescence resonance energy transfer (FRET) biosensor by choosing the upconversion NaYF4:Yb3+/Tm3+ nanoparticles as the energy donor and the CdTe QDs as the energy acceptor for lead ion detection. It is the first near infrared (NIR)-excited fluorescent probe for determination of lead ions in serum that is capable of overcoming self-luminescence from serum excitation with visible light. The sensor also shows high selectivity, a low detection limit (80 nm) and good linear Stern-Volmer characteristics (R = 0.996), both in the buffer and serum. This biosensor has great potential for versatile applications in lead ion detection in biological and analytical fields.There has been great progress in the development of fluorescence biosensors based on quantum dots (QDs) for the detection of lead ions. However, most methods are detecting lead ions in aqueous solution rather than in human serum due to the influence of protein autofluorescence in serum excited by visible light. Thus, we developed a novel fluorescence resonance energy transfer (FRET) biosensor by choosing the upconversion NaYF4:Yb3+/Tm3+ nanoparticles as the energy donor and the CdTe QDs as the energy acceptor for lead ion detection. It is the first near infrared (NIR)-excited fluorescent probe for determination of lead ions in serum that is capable of overcoming self-luminescence from serum excitation with visible light. The sensor also shows high selectivity, a low detection limit (80 nm) and good linear Stern-Volmer characteristics (R = 0.996), both in the buffer and serum. This biosensor has great potential for versatile applications in lead ion detection in biological and

  17. The energy scaling in a side-pumped ultra-low-magnification unstable resonator by employing a compact master oscillator power amplifier

    Science.gov (United States)

    Cho, C. Y.; Huang, Y. P.; Su, K. W.

    2016-10-01

    The energy scaling for a diode-side-pumped passively Q-switched Nd:YAG laser in an ultra-low-magnification unstable convex-concave resonator is investigated. Theoretical analysis and experimental results indicate the fact that the energy scaling is restricted by the increasing of side-pumping sources inside the resonator because of the significant pump-to-mode size mismatching. It is verified that employing the master oscillation power amplifier can effectively enlarge the output pulse energy and improve the beam quality. Up to 60-mJ pulse energy with 17-MW peak power is obtained at a pump energy of 520 mJ. A 1573-nm eye-safe laser emission with pulse energy up to 25 mJ is further attended via the extracavity optical parametric oscillator.

  18. Photoionization mass spectrometric study of the prebiotic species formamide in the 10-20 eV photon energy range.

    Science.gov (United States)

    Leach, Sydney; Jochims, Hans-Werner; Baumgärtel, Helmut

    2010-04-15

    A photoion mass spectrometry study of the prebiotic species formamide was carried out using synchrotron radiation over the photon energy range 10-20 eV. Photoion yield curves were measured for the parent ion and seven fragment ions. The ionization energy of formamide was determined as IE (1(2)A') = 10.220 +/- 0.005 eV, in agreement with a value obtained by high resolution photoelectron spectroscopy. The adiabatic energy of the first excited state of the ion, 1(2)A'', was revised to 10.55 eV. A comparison of the ionization energies of related formamides, amino acids, and polypeptides provides useful information on the varied effects of methylation and shows that polymerization does not substantially alter the ionization properties of the amino acid monomer units. Assignments of the fragment ions and the pathways of their formation by dissociative photoionization were made on the basis of ion appearance energies in conjunction with thermochemical data and the results of earlier electron impact mass spectral studies. Some of the dissociation pathways are considered to involve coupling between the 1(2)A' ground state and the low-lying 1(2)A'' excited state of the cation. Heats of formation are derived for all ions detected and are compared with literature values where they exist. Formation of the HNCO(+) ion occurs by two separate paths, one involving H(2) loss, the other H + H. In the conclusion a brief discussion is given of some astrophysical implications of these results.

  19. Quantum mechanical free energy profiles with post-quantization restraints: Binding free energy of the water dimer over a broad range of temperatures

    Science.gov (United States)

    Bishop, Kevin P.; Roy, Pierre-Nicholas

    2018-03-01

    Free energy calculations are a crucial part of understanding chemical systems but are often computationally expensive for all but the simplest of systems. Various enhanced sampling techniques have been developed to improve the efficiency of these calculations in numerical simulations. However, the majority of these approaches have been applied using classical molecular dynamics. There are many situations where nuclear quantum effects impact the system of interest and a classical description fails to capture these details. In this work, path integral molecular dynamics has been used in conjunction with umbrella sampling, and it has been observed that correct results are only obtained when the umbrella sampling potential is applied to a single path integral bead post quantization. This method has been validated against a Lennard-Jones benchmark system before being applied to the more complicated water dimer system over a broad range of temperatures. Free energy profiles are obtained, and these are utilized in the calculation of the second virial coefficient as well as the change in free energy from the separated water monomers to the dimer. Comparisons to experimental and ground state calculation values from the literature are made for the second virial coefficient at higher temperature and the dissociation energy of the dimer in the ground state.

  20. Communication: energy-dependent resonance broadening in symmetric and asymmetric molecular junctions from an ab initio non-equilibrium Green's function approach.

    Science.gov (United States)

    Liu, Zhen-Fei; Neaton, Jeffrey B

    2014-10-07

    The electronic structure of organic-inorganic interfaces often features resonances originating from discrete molecular orbitals coupled to continuum lead states. An example is molecular junction, individual molecules bridging electrodes, where the shape and peak energy of such resonances dictate junction conductance, thermopower, I-V characteristics, and related transport properties. In molecular junctions where off-resonance coherent tunneling dominates transport, resonance peaks in the transmission function are often assumed to be Lorentzian functions with an energy-independent broadening parameter Γ. Here we define a new energy-dependent resonance broadening function, Γ(E), based on diagonalization of non-Hermitian matrices, which can describe resonances of a more complex, non-Lorentzian nature and can be decomposed into components associated with the left and right leads, respectively. We compute this quantity via an ab initio non-equilibrium Green's function (NEGF) approach based on density functional theory (DFT) for both symmetric and asymmetric molecular junctions, and show that our definition of Γ(E), when combined with Breit-Wigner formula, reproduces the transmission calculated from DFT-NEGF. Through a series of examples, we illustrate how this approach can shed new light on experiments and understanding of junction transport properties in terms of molecular orbitals.

  1. Ionization Energies, Electron Affinities, and Polarization Energies of Organic Molecular Crystals: Quantitative Estimations from a Polarizable Continuum Model (PCM)–Tuned Range-Separated Density Functional Approach

    KAUST Repository

    Sun, Haitao

    2016-05-16

    We propose a new methodology for the first-principles description of the electronic properties relevant for charge transport in organic molecular crystals. This methodology, which is based on the combination of a non-empirical, optimally tuned range-separated hybrid functional with the polarizable continuum model, is applied to a series of eight representative molecular semiconductor crystals. We show that it provides ionization energies, electron affinities, and transport gaps in very good agreement with experimental values as well as with the results of many-body perturbation theory within the GW approximation at a fraction of the computational costs. Hence, this approach represents an easily applicable and computationally efficient tool to estimate the gas-to-crystal-phase shifts of the frontier-orbital quasiparticle energies in organic electronic materials.

  2. Measurement of Inverse Pion Photoproduction at Energies Spanning the N(1440) Resonance

    CERN Document Server

    Shafi, A; Strakovsky, I I; Briscoe, W J; Nefkens, B M K; Allgower, C E; Arndt, R A; Bekrenev, V; Bennhold, C; Clajus, M; Comfort, J R; Craig, K; Grosnick, D P; Isenhower, D; Knecht, N; Koetke, D D; Kulbardis, A; Kozlenko, N; Kruglov, S; Lolos, G J; Lopatin, I; Manley, D M; Manweiler, R; Marusic, A; McDonald, S; Olmsted, J; Papandreou, Z; Peaslee, D; Phaisangittisakul, N; Price, J W; Ramírez, A F; Sadler, M; Spinka, H; Stanislaus, T D S; Starostin, A; Staudenmaier, H M; Supek, I; Tippens, W B; Workman, R L; Workman, and R.L.

    2004-01-01

    Differential cross sections for the process pi^- p -> gamma n have been measured at Brookhaven National Laboratory's Alternating Gradient Synchrotron with the Crystal Ball multiphoton spectrometer. Measurements were made at 18 pion momenta from 238 to 748 MeV/c, corresponding to E_gamma for the inverse reaction from 285 to 769 MeV. The data have been used to evaluate the gamma n multipoles in the vicinity of the N(1440) resonance. We compare our data and multipoles to previous determinations. A new three-parameter SAID fit yields 36 +/- 7 (GeV)^-1/2 X 10^-3 for the A^n_1/2 amplitude of the P_11.

  3. Energy-efficient tunable silicon photonic micro-resonator with graphene transparent nano-heaters

    CERN Document Server

    Yu, Longhai; Dai, Daoxin; He, Sailing

    2015-01-01

    Thermally-tuning silicon micro-cavities are versatile and beneficial elements in low-cost large-scale photonic integrated circuits (PICs). Traditional metal heaters used for thermal tuning in silicon micro-cavities usually need a thick SiO2 upper-cladding layer, which will introduce some disadvantages including low response speed, low heating efficiency, low achievable temperature and complicated fabrication processes. In this paper, we propose and experimentally demonstrate thermally-tuning silicon micro-disk resonators by introducing graphene transparent nano-heaters, which contacts the silicon core directly without any isolator layer. This makes the graphene transparent nano-heater potentially to have excellent performances in terms of the heating efficiency, the temporal response and the achievable temperature. It is also shown that the graphene nano-heater is convenient to be used in ultrasmall photonic integrated devices due to the single-atom thickness and excellent flexibility of graphene. Both experi...

  4. Determination of effective resonance energy for the 193Ir(n,γ)194Ir reaction by the cadmium ratio method

    Science.gov (United States)

    Budak, Mustafa Guray; Karadag, Mustafa; Yücel, Haluk

    2016-04-01

    In this work, the effective resonance energy, Ebarr -value for the 193Ir(n,γ)194Ir reaction was measured using cadmium ratio method. A dual monitor (197Au-98Mo), which has convenient resonance properties, was employed for characterization of the irradiation sites. Then analytical grade iridium oxide samples diluted with CaCO3 to lower neutron self-shielding effect stacked in small cylindrical Teflon boxes were irradiated once with a 1 mm thick Cd cylindrical box placed in a thermalized neutron field of an 241Am-Be neutron source then without it. The activities produced in samples during 193Ir(n,γ)194Ir reaction were measured using a p-type HPGe detector γ-ray spectrometer with a 44.8% relative efficiency. The correction factors for thermal, epithermal neutron self-shielding (Gth, Gepi), true coincidence summing (Fcoi) and gamma-ray self-absorption (Fs) effects were determined with appropriate approaches and programs. Thus, the experimental Ebarr -value was determined to be 2.65 ± 0.61 eV for 193Ir target nuclide. The recent data for Q0 and FCd values for Ebarr determination were based on k0-NAA online database. The present experimental Ebarr value was calculated and compared with more recent values for Q0 and FCd for 193Ir. Additionally, the Ebarr -values was theoretically calculated from the up-to-date resonance data obtained from ENDF/B VII library using two different approaches. Since there is no experimentally determined Ebarr -value for the 193Ir isotope, the results are compared with the calculated ones given in the literature.

  5. A wide range of energy spin-filtering in a Rashba quantum ring using S-matrix method

    Science.gov (United States)

    Naeimi, Azadeh S.; Eslami, Leila; Esmaeilzadeh, Mahdi

    2013-01-01

    In this paper, spin-filtering properties of transmitted electrons through a quantum ring in the presence of Rashba spin-orbit interaction and magnetic flux are studied. To investigate the effects of coupling between the leads and ring on the spin-filtering, the S-matrix method is used. It is shown that by tuning the Rashba spin-orbit strength and the magnetic flux, the quantum ring can act as a perfect spin-filter with high efficiency. The spin-filtering can be changed from spin up to spin down and vice versa by changing the Rashba strength when the magnetic flux is held constant or by changing the magnetic flux when the Rashba strength is held constant. In addition, the effect of the angle between the leads on spin-filtering properties is taken into account and the angles at which the spin-filtering can occur are determined. The spin-filtering can take place in narrow ranges of electron energy for weak coupling, while for strong coupling it can take place in a wide range of electron energy.

  6. Cross sections for electron scattering by methylfluoride (CH{sub 3}F) in the low- and intermediate-energy ranges

    Energy Technology Data Exchange (ETDEWEB)

    Ferraz, J.R.; Santos, A.S. dos [Departamento de Física, UFSCar, 13565-905 São Carlos, SP (Brazil); Souza, G.L.C. de; Lee, M.-T. [Departamento de Química, UFSCar, 13565-905 São Carlos, SP (Brazil); Brescansin, L.M. [Instituto de Física “Gleb Wataghin”, UNICAMP, 13083-970 Campinas, SP (Brazil); Lucchese, R.R. [Department of Chemistry, Texas A and M University, College Station, TX 7784-3255 (United States); Machado, L.E., E-mail: dlem@df.ufscar.br [Departamento de Física, UFSCar, 13565-905 São Carlos, SP (Brazil)

    2014-03-01

    Highlights: • Theoretical investigation on e{sup −}–CH{sub 3}F collisions. • Complex optical potential is used to evaluate elastic, total, and total absorption cross sections. • Single-center expansion, combined with the Padé approximant technique, is used to solve the scattering equations. • Calculated results are in good agreement with existing theoretical and experimental data. - Abstract: We report a theoretical study on electron scattering by methylfluoride (CH{sub 3}F) in the intermediate-energy range. Calculated elastic differential, integral, and momentum-transfer, as well as grand-total (elastic + inelastic) and total absorption cross sections are reported for impact energies ranging from 15 to 500 eV. A complex optical potential is used to represent the electron–molecule interaction dynamics. A theoretical method based on the single-center-expansion close-coupling framework and corrected by the Padé approximant technique is used to solve the scattering equations. The comparison of our calculated results with experimental and other available theoretical data is encouraging.

  7. Survey on the international cooperation for resonable use techniques of energy; Energy shiyo gorika shuho kokusai kyoryoku chosa

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    LCA (life cycle assessment) is known as one of the techniques for assessing reasonable use of energy considering environment. Usefulness of LCA was examined by checking the consistency between the assessment result on refrigerators by LCA and ISO standards. LCA can digitize the data on energy substances, wastes and emission of the whole system. LCA is useful for effective use and control of resources, and to clarify the reduction chance of environmental impacts. However, the framework is necessary to estimate the accuracy of assessment technique for every category, and the reliability of influence assessment. Like a risk assessment for environmental damages, identification of discharge sources beyond the assessment function of potentials is difficult. As the viewpoint of the whole life cycle is important, assessment of local damages is difficult. The complementary use of LCA and other tools about sustainable development is important. The comparison result between ISO provisions and this LCA case study showed that this concrete research report can play a role as text book for the ISO technique. 74 refs., 38 figs., 45 tabs.

  8. Study of unfolding methods for X-ray spectra obtained with CDTE detectors in the mammography energy range

    Energy Technology Data Exchange (ETDEWEB)

    Querol, A.; Gallardo, S.; Rodenas, J.; Verdu, G.; Barrachina, T. [Departamento de Ingenieria Quimica y Nuclear, Universidad Politecnica de Valencia, Cami de Vera, s/n 46022 Valencia (Spain)

    2010-07-01

    Quality control parameters for an X-ray tube strongly depend on the accurate knowledge of the primary spectrum, but it is difficult to obtain it experimentally by direct measurements. Indirect spectrometry techniques such as Compton scattering can be used in X-ray spectrum assessment avoiding the pile-up effect in detectors. However, an unfolding method is required for this kind of measurements. In previous works, a methodology to assess primary X-ray spectra in the diagnostic energy range by means of the Compton scattering technique has been analysed. This methodology included a Monte Carlo simulation model, using the MCNP5 code, of the actual experimental set-up providing a Pulse Height Distribution (PHD) for a given primary spectrum. It reproduced the interaction of photons and electrons with the Compton spectrometer and with a High Purity Germanium detector. In this work, a CdTe detector is proposed instead of the HP Germanium. CdTe detector does not require a liquid nitrogen cooling system, but its resolution is poor for the same energy range and its efficiency comes down for energies greater than 55 keV being 70% at 90 keV. In despite of these disadvantages, CdTe detector has been considered due to its low cost and easy handling and portability. The model can provide a PHD and a Response Matrix, for different X-ray spectra, taken from the IPEM 78 catalogue. The primary spectrum can be estimated applying the MTSVD (Modified Truncated Singular Value Decomposition) and the Tikhonov unfolding method. Both unfolding methods cause some loss of information on the reconstructed primary spectra. In this paper, a comparison of the ability to obtain primary spectra using both MTSVD and Tikhonov unfolding methods has been done. As well a sensitivity analysis in order to test the proposed unfolding methods when they are applied to PHDs obtained with the MCNP model has been developed. A variation on parameters such as target materials and voltages over the mammography

  9. Energy transport in the three coupled α-polypeptide chains of collagen molecule with long-range interactions effect

    Science.gov (United States)

    Mvogo, Alain; Ben-Bolie, G. H.; Kofané, T. C.

    2015-06-01

    The dynamics of three coupled α-polypeptide chains of a collagen molecule is investigated with the influence of power-law long-range exciton-exciton interactions. The continuum limit of the discrete equations reveal that the collagen dynamics is governed by a set of three coupled nonlinear Schrödinger equations, whose dispersive coefficient depends on the LRI parameter r. We construct the analytic symmetric and asymmetric (antisymmetric) soliton solutions, which match with the structural features of collagen related with the acupuncture channels. These solutions are used as initial conditions for the numerical simulations of the discrete equations, which reveal a coherent transport of energy in the molecule for r > 3. The results also indicate that the width of the solitons is a decreasing function of r, which help to stabilize the solitons propagating in the molecule. To confirm further the efficiency of energy transport in the molecule, the modulational instability of the system is performed and the numerical simulations show that the energy can flow from one polypeptide chain to another in the form of nonlinear waves.

  10. Testing and Comparison of Imaging Detectors for Electrons in the Energy Range 10–20 keV

    Science.gov (United States)

    Matheson, J.; Moldovan, G.; Kirkland, A.; Allinson, N.; Abrahams, J. P.

    2017-11-01

    Interest in direct detectors for low-energy electrons has increased markedly in recent years. Detection of electrons in the energy range up to low tens of keV is important in techniques such as photoelectron emission microscopy (PEEM) and electron backscatter diffraction (EBSD) on scanning electron microscopes (SEMs). The PEEM technique is used both in the laboratory and on synchrotron light sources worldwide. The ubiquity of SEMs means that there is a very large market for EBSD detectors for materials studies. Currently, the most widely used detectors in these applications are based on indirect detection of incident electrons. Examples include scintillators or microchannel plates (MCPs), coupled to CCD cameras. Such approaches result in blurring in scintillators/phosphors, distortions in optical systems, and inefficiencies due the limited active area of MCPs. In principle, these difficulties can be overcome using direct detection in a semiconductor device. Growing out of a feasibility study into the use of a direct detector for use on an XPEEM, we have built at Rutherford Appleton Laboratory a system to illuminate detectors with an electron beam of energy up to 20 keV . We describe this system in detail. It has been used to measure the performance of a custom back-thinned monolithic active pixel sensor (MAPS), a detector based on the Medipix2 chip, and a commercial detector based on MCPs. We present a selection of the results from these measurements and compare and contrast different detector types.

  11. Measurements and Monte Carlo calculations with the extended-range Bonner sphere spectrometer at high-energy mixed fields

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00406842; Bay, Aurelio; Silari, Marco; Aroua, Abbas

    The use of spectrometry to provide information for neutron radiation protection has become an increasingly important activity over recent years. The need for spectral data arises because neither area survey instruments nor personal dosimeters give the correct dose equivalent results at all neutron energies. It is important therefore to know the spectra of the fields in which these devices are used. One of the systems most commonly employed in neutron spectrometry and dosimetry is the Bonner Sphere Spectrometers (BSS). The extended- range BSS that was used for this work, consists of 7 spheres with an overall response to neutrons up to 2 GeV. A 3He detector is used as a thermal counter in the centre of each sphere. In the context of this thesis the BSS was calibrated in monoenergetic neutron fields at low and intermediate energies. It was also used for measurements in several high energy mixed fields. These measurements have led to the calculation of neutron yields and spectral fluences from unshielded targets....

  12. Stochasticity of the energy absorption in the electron cyclotron resonance; Estocasticidad de la absorcion de energia en la resonancia electron-ciclotronica

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez T, C. [Departamento de Fisica, ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico); Hernandez A, O

    1998-07-01

    The energy absorption mechanism in cyclotron resonance of the electrons is a present problem, since it could be considered from the stochastic point of view or this related with a non-homogeneous but periodical of plasma spatial structure. In this work using the Bogoliubov average method for a multi periodical system in presence of resonances, the drift equations were obtained in presence of a RF field for the case of electron cyclotron resonance until first order terms with respect to inverse of its cyclotron frequency. The absorbed energy equation is obtained on part of electrons in a simple model and by drift method. It is showed the stochastic character of the energy absorption. (Author)

  13. A molecularly imprinted polymer-coated CdTe quantum dot nanocomposite for tryptophan recognition based on the Förster resonance energy transfer process

    Science.gov (United States)

    Tirado-Guizar, Antonio; Paraguay-Delgado, Francisco; Pina-Luis, Georgina E.

    2016-12-01

    A new ‘turn-on’ Förster resonance energy transfer (FRET) nanosensor for l-tryptophan based on molecularly imprinted quantum dots (QDs) is proposed. The approach combines the advantages of the molecular imprinting technique, the fluorescent characteristics of the QDs and the energy transfer process. Silica-coated CdTe QDs were first synthesized and then molecularly imprinted using a sol-gel process without surfactants. The final composite presents stable fluorescence which increases with the addition of l-tryptophan. This ‘turn-on’ response is due to a FRET mechanism from the l-tryptophan as donor to the imprinted QD as acceptor. QDs are rarely applied as acceptors in FRET systems. The nanosensor shows selectivity towards l-tryptophan in the presence of other amino acids and interfering ions. The l-tryptophan nanosensor exhibits a linear range between 0 and 8 µM concentration, a detection limit of 350 nM and high selectivity. The proposed sensor was successfully applied for the detection of l-tryptophan in saliva. This novel sensor may offer an alternative approach to the design of a new generation of imprinted nanomaterials for the recognition of different analytes.

  14. Acriflavine-immobilized eggshell membrane as a new solid-state biosensor for Sudan I-IV detection based on fluorescence resonance energy transfer.

    Science.gov (United States)

    Li, Ying; Wang, Anyi; Bai, Yunfei; Wang, Shiping

    2017-12-15

    A novel solid-surface fluorescence biosensor for rapid detection of Sudan I-IV was proposed based on fluorescence resonance energy transfer (FRET). The biosensor was fabricated by immobilizing acriflavine (AY) on the eggshell membrane (ESM) with glutaraldehyde as cross-linking agent. FRET mechanism was demonstrated by using AY and Sudan dyes as donor and acceptor respectively, an efficient energy transfer in the present system was indicated by the sufficient spectral overlap integral (J) and proper Förster critical distance (R 0 ). Under optimum conditions, the fluorescence of the AY-ESM could be efficiently quenched by Sudan I-IV and the corresponding linear range was 0.5-60μM with the detection limits (3σ/slope) of 0.16, 0.26, 0.21 and 0.17μM respectively. Compared to the detection of Sudan dyes in solution-state, the membrane biosensor exhibited advantages of low detection limits, high sensitivity and selectivity, as well as excellent stability. Recovery tests in spiked real samples also achieved satisfactory results. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. RuSi@Ru(bpy)3(2+)/Au@Ag2S nanoparticles electrochemiluminescence resonance energy transfer system for sensitive DNA detection.

    Science.gov (United States)

    Wu, Mei-Sheng; He, Li-Jing; Xu, Jing-Juan; Chen, Hong-Yuan

    2014-05-06

    This work describes a new electrochemiluminescence resonance energy transfer (ECL-RET) system with graphene oxide(GO)-Au/RuSi@Ru(bpy)3(2+)/chitosan (CS) composites as the ECL donor and Au@Ag2S nanoparticles (NPs) as ECL the acceptor for the first time. The ECL signal observed by the application of GO-Au/RuSi@Ru(bpy)3(2+)/CS composites was enhanced for 5-fold compared to that of RuSi@Ru(bpy)3(2+)/CS in the presence of coreactant tripropylamine (TPA) due to the increased surface area and improved electrical conductivity by using graphene oxide-gold nanoparticles (GO-Au) composite materials. In addition, we synthesized Au@Ag2S core-shell NPs, whose UV-vis absorption spectrum shows good spectral overlap with the ECL spectrum of GO-Au/RuSi@Ru(bpy)3(2+)/CS composites by adjusting the amount of Na2S and AgNO3 in the process of synthesis. The distance between energy donor and acceptor was studied to get the highly effective ECL-RET. Then, this ECL-RET system was developed for sensitive and specific detection of target DNA, and the ECL quenching efficiency (ΔI/I0, ΔI = I0 - I) was found to be logarithmically related to the concentration of the target DNA in the range from 10 aM to 10 pM.

  16. Identification of a new low energy 1ustate in dicopper with resonant four-wave mixing.

    Science.gov (United States)

    Visser, B; Beck, M; Bornhauser, P; Knopp, G; van Bokhoven, J A; Marquardt, R; Gourlaouen, C; Radi, P P

    2017-12-07

    The low energy electronic structure of the copper dimer has been re-investigated using non-linear four-wave mixing spectroscopy and high level ab initio calculations. In addition to the measurement of the previously reported A, B, and C electronic states, a new state denoted A' is identified with T 0 = 20 100.4090(16) cm -1 ( 63 Cu 2 ). Rotational analysis of the A'-X (0,0) and (1,0) transitions leads to the assignment of A' 1 u . Ab initio calculations present the first theoretical description of the low energy states of the copper dimer in Hund's case (c) and confirm the experimental assignment. The discovery of this new low energy excited state emphasizes that spin-orbit coupling is significant in states with d-hole electronic configurations and resolves a decades-long mystery in the initial assignment of the A state.

  17. SU-E-CAMPUS-J-06: The Impact of CT-Scan Energy On Range Uncertainty in Proton Therapy Planning

    Energy Technology Data Exchange (ETDEWEB)

    Grantham, K [University of Missouri-Columbia, St. Louis, MO (United States); Li, H [Washington University School of Medicine, Saint Louis, MO (United States); Zhao, T [Washington University School of Medicine, St. Louis, MO (United States); Klein, E [Washington University, Saint Louis, MO (United States)

    2014-06-15

    Purpose: To investigate the impact of tube potential (kVp) on the CTnumber (HU) to proton stopping power ratio (PSPR) conversion table; the range uncertainty and the dosimetric change introduced by a mismatch in kVp between the CT and the HU to PSPR table used to calculate dose are analyzed. Methods: A CIRS CT-ED phantom was scanned with a Philips Brilliance 64-slice scanner under 90kVp and 120kVp tube potentials. Two HU to PSPR curves were then created. Using Eclipse (Varian) a treatment plan was created for a single beam in a water phantom (HU=0) passing through a wedge-shaped heterogeneity (HU=1488). The dose was recalculated by changing only the HU to PSPR table used in the dose calculation. The change in range (the distal 90% isodose line) relative to a distal structure was recorded as a function of heterogeneity thickness in the beam. To show the dosimetric impact of a mismatch in kVp between the CT and the HU to PSPR table, we repeated this procedure using a clinical plan comparing DVH data. Results: The HU to PSPR tables diverge for low-density bone and higher density structures. In the phantom plan, the divergence of the tables results in a change in range of ~1mm per cm of bone in the beam path for the HU used. For the clinical plan, a mismatch in kVp showed a 28% increase in mean dose to the brainstem along with a 10% increase in maximum dose to the brainstem center. Conclusion: A mismatch in kVp between the CT and the HU to PSPR table can introduce significant uncertainty in the proton beam range. For dense bone, the measured range uncertainty is about 1mm per cm of bone in the beam. CT-scan energy verification should be employed, particularly when high-density media is in the proton beam path.

  18. Bioluminescence resonance energy transfer from aequorin to a fluorophore: an artificial jellyfish for applications in multianalyte detection.

    Science.gov (United States)

    Deo, Sapna K; Mirasoli, Mara; Daunert, Sylvia

    2005-04-01

    In nature, the green light emission observed in the jellyfish Aequorea victoria is a result of a non-radiative energy transfer from the excited-state aequorin to the green fluorescent protein. In this work, we have modified the photoprotein aequorin by attaching selected fluorophores at a unique site on the protein. This will allow for in vitro transfer of bioluminescent energy from aequorin to the fluorophore thus creating an "artificial jellyfish". The fluorophores are selected such that the excitation spectrum of the fluorophore overlaps with the emission spectrum of aequorin. By modifying aequorin with different fluorophores, bioluminescent labels with different emission maxima are produced, which will allow for the simultaneous detection of multiple analytes. By examining the X-ray crystal structure of the protein, four different sites for introduction of the unique cysteine residue were evaluated. Two fluorophores with differing emission maxima were attached individually to the mutants through the sulfhydryl group of the cysteine molecule. Two of the fluorophore-labeled mutants showed a peak corresponding to fluorophore emission thus indicating resonance energy transfer from aequorin to the fluorophore.

  19. Construction of a controllable Förster resonance energy transfer system based on G-quadruplex for DNA sensing.

    Science.gov (United States)

    Yue, Qiaoli; Shen, Tongfei; Wang, Changna; Wang, Lei; Li, Haibo; Xu, Shuling; Wang, Huaisheng; Liu, Jifeng

    2013-02-15

    Conjugations of oligonucleotides, chromophores, and gold nanoparticles (GNPs) can be used for energy transfer assays to detect DNA. Herein, a homogenous Förster resonance energy transfer (FRET) system employing two-step modification of oligonucleotide on GNPs was reported. The distance between the donor (fluorescein attached onto DNA) and the acceptor (GNPs) was controlled by using the G-rich DNA. In the presence of porphyrin or berberine, which can act as ligands of G-quadruplexes, the G-rich DNA spacer can result into G-quadruplex structure. Therefore, the intimate contact between the fluorophore and the GNP results in efficient energy transfer and fluorescence quenching. After hybridization with target DNA, the G-quadruplex stretched and resulted in an enhancement of fluorescence. So the present FRET system can be used for target DNA sensing with detection limit as low as 40 pM (S/N=3). In this study, a relation between the fluorescence quenching efficiency and GNP sizes was found and bigger GNPs had higher fluorescence enhancement after hybridization with target DNA. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Graphene quantum dot antennas for high efficiency Förster resonance energy transfer based dye-sensitized solar cells

    Science.gov (United States)

    Subramanian, Alagesan; Pan, Zhenghui; Rong, Genlan; Li, Hongfei; Zhou, Lisha; Li, Wanfei; Qiu, Yongcai; Xu, Yijun; Hou, Yuan; Zheng, Zhaozhao; Zhang, Yuegang

    2017-03-01

    The light harvesting efficiency of an acceptor dye can be enhanced by judicious choice and/or design of donor materials in the Förster resonance energy transfer (FRET) based dye-sensitized solar cells (DSSCs). In this work, we explore graphene quantum dots (GQDs) as energy relay antennas for the high power conversion efficiency Ru-based N719 acceptor dyes. The absorption, emission, and time decay spectral results evidence the existence of the FRET, the radiative energy transfer (RET), and a synergistic interaction between GQDs and N719 dye. The FRET efficiency is measured to be 27%. The GQDs co-sensitized DSSC achieves an efficiency (ƞ) of 7.96% with a Jsc of 16.54 mAcm-2, which is 30% higher than that of a N719-based DSSC. GQDs also reduce the charge recombination, which results in an increased open-circuit voltage up to 770 mV. The incident photon-to-current conversion efficiency and UV-Vis absorption measurement reveal that the enhanced absorption of the GQDs antennas is responsible for the improved Jsc in the whole UV-Visible region, while the RET/FRET and the synergistic effect contribute to the significant increase of Jsc in the UV region.

  1. Numerical method to calculate the quantum transmission, resonance and eigenvalue energies: application to a biased multibarrier systems

    Energy Technology Data Exchange (ETDEWEB)

    Maiz, F., E-mail: fethimaiz@gmail.com [University of Cartage, Nabeul Engineering Preparatory Institute, Merazka, 8000 Nabeul (Tunisia); King Khalid University, Faculty of Science, Physics Department, PO Box 9004, Abha 61413 (Saudi Arabia)

    2015-04-15

    A novel method to calculate the quantum transmission, resonance and eigenvalue energies forming the sub-bands structure of non-symmetrical, non-periodical semiconducting heterostructure potential has been proposed in this paper. The method can be applied on a multilayer system with varying thickness of the layer and effective mass of electrons and holes. Assuming an approximated effective mass and using Bastard's boundary conditions, Schrödinger equation at each media is solved and then using a confirmed recurrence method, the transmission and reflection coefficients and the energy quantification condition are expressed. They are simple combination of coupled equations. Schrödinger's equation solutions are Airy functions or plane waves, depending on the electrical potential energy slope. To illustrate the feasibility of the proposed method, the N barriers – (N−1) wells structure for N=3, 5, 8, 9, 17 and 35 are studied. All results show very good agreements with previously published results obtained from applying different methods on similar systems.

  2. Time-resolved spectroscopy and fluorescence resonance energy transfer in the study of excimer laser damage of chromatin

    Energy Technology Data Exchange (ETDEWEB)

    Radu, L. [Department of Molecular Genetics and Radiobiology, Babes National Institute, Bucharest (Romania)], E-mail: lilianajradu@yahoo.fr; Mihailescu, I. [Department of Lasers, Laser, Plasma and Radiation Physics Institute, Bucharest (Romania); Radu, S. [Department of Computer Science, Polytechnics University, Bucharest (Romania); Gazdaru, D. [Department of Biophysics, Bucharest University (Romania)

    2007-09-21

    The analysis of chromatin damage produced by a 248 nm excimer laser radiation, for doses of 0.3-3 MJ/m{sup 2} was carried out by time-resolved spectroscopy and fluorescence resonance energy transfer (FRET). The chromatin was extracted from a normal and a tumoral tissue of Wistar rats. The decrease with laser dose of the relative contribution of the excited state lifetimes of ethidium bromide (EtBr) bounded to chromatin constitutes an evidence of the reduction of chromatin deoxyribonucleic acid (DNA) double-strand structure. FRET was performed from dansyl chloride to acridine orange, both coupled to chromatin. The increase of the average distance between these ligands, under the action of laser radiation, reflects a loosening of the chromatin structure. The radiosensitivity of tumor tissue chromatin is higher than that of a normal tissue. The determination of the chromatin structure modification in an excimer laser field can be of interest in laser therapy.

  3. Screening for protein-protein interactions using Förster resonance energy transfer (FRET) and fluorescence lifetime imaging microscopy (FLIM).

    Science.gov (United States)

    Margineanu, Anca; Chan, Jia Jia; Kelly, Douglas J; Warren, Sean C; Flatters, Delphine; Kumar, Sunil; Katan, Matilda; Dunsby, Christopher W; French, Paul M W

    2016-06-24

    We present a high content multiwell plate cell-based assay approach to quantify protein interactions directly in cells using Förster resonance energy transfer (FRET) read out by automated fluorescence lifetime imaging (FLIM). Automated FLIM is implemented using wide-field time-gated detection, typically requiring only 10 s per field of view (FOV). Averaging over biological, thermal and shot noise with 100's to 1000's of FOV enables unbiased quantitative analysis with high statistical power. Plotting average donor lifetime vs. acceptor/donor intensity ratio clearly identifies protein interactions and fitting to double exponential donor decay models provides estimates of interacting population fractions that, with calibrated donor and acceptor fluorescence intensities, can yield dissociation constants. We demonstrate the application to identify binding partners of MST1 kinase and estimate interaction strength among the members of the RASSF protein family, which have important roles in apoptosis via the Hippo signalling pathway. KD values broadly agree with published biochemical measurements.

  4. Resonant structures in the low-energy electron continuum for single ionization of atoms in the tunnelling regime

    Energy Technology Data Exchange (ETDEWEB)

    Rudenko, A; Zrost, K; Schroeter, C D; Jesus, V L B de; Feuerstein, B; Moshammer, R; Ullrich, J [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-67119 Heidelberg (Germany)

    2004-12-28

    We present high-resolution fully differential experimental data on single ionization of He, Ne and Ar by ultra-short (25 fs, 6 fs) 795 nm laser pulses at intensities 0.15-2.0 x 10{sup 15} W cm{sup -2}. We show that the ATI-like pattern can survive deep in the tunnelling regime and that the atomic structure plays an important role in the formation of the low-energy photoelectron spectra even at high intensities. The absence of ponderomotive shifts, the splitting of the peaks and their degeneration for few-cycle pulses indicate that the observed structures originate from a resonant process. (letter to the editor)

  5. Micro-RNA detection based on fluorescence resonance energy transfer of DNA-carbon quantum dots probes.

    Science.gov (United States)

    Khakbaz, Faeze; Mahani, Mohamad

    2017-04-15

    Carbon quantum dots have been proposed as an effective platform for miRNA detection. Carbon dots were synthesized by citric acid. The synthesized dots were characterized by dynamic light scattering, UV-Vis spectrophotometry, spectrofluorimetry, transmission electron microscopy and FT-IR spectrophotometry. The fluorescence quantum yield of the synthesized dots was determined using quinine sulfate as the standard. The FAM-labeled single stranded DNA, as sensing element, was adsorbed on dots by π-π interaction. The quenching of the dots fluorescence due to fluorescence resonance energy transfer (FRET) was used for mir 9-1 detection. In the presence of the complementary miRNA, the FRET did not take place and the fluorescence was recovered. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Observations of a free-energy source for intense electrostatic waves. [in upper atmosphere near upper hybrid resonance frequency

    Science.gov (United States)

    Kurth, W. S.; Frank, L. A.; Gurnett, D. A.; Burek, B. G.; Ashour-Abdalla, M.

    1980-01-01

    Significant progress has been made in understanding intense electrostatic waves near the upper hybrid resonance frequency in terms of the theory of multiharmonic cyclotron emission using a classical loss-cone distribution function as a model. Recent observations by Hawkeye 1 and GEOS 1 have verified the existence of loss-cone distributions in association with the intense electrostatic wave events, however, other observations by Hawkeye and ISEE have indicated that loss cones are not always observable during the wave events, and in fact other forms of free energy may also be responsible for the instability. Now, for the first time, a positively sloped feature in the perpendicular distribution function has been uniquely identified with intense electrostatic wave activity. Correspondingly, we suggest that the theory is flexible under substantial modifications of the model distribution function.

  7. High-efficiency Förster resonance energy transfer in solid-state dye sensitized solar cells.

    Science.gov (United States)

    Mor, Gopal K; Basham, James; Paulose, Maggie; Kim, Sanghoon; Varghese, Oomman K; Vaish, Amit; Yoriya, Sorachon; Grimes, Craig A

    2010-07-14

    Solid-state dye-sensitized solar cells (SS-DSCs) offer the potential to make low cost solar power a reality, however their photoconversion efficiency must first be increased. The dyes used are commonly narrow band with high absorption coefficients, while conventional photovoltaic operation requires proper band edge alignment significantly limiting the dyes and charge transporting materials that can be used in combination. We demonstrate a significant enhancement in the light harvesting and photocurrent generation of SS-DSCs due to Förster resonance energy transfer (FRET). TiO(2) nanotube array films are sensitized with red/near IR absorbing SQ-1 acceptor dye, subsequently intercalated with Spiro-OMeTAD blended with a visible light absorbing DCM-pyran donor dye. The calculated Förster radius is 6.1 nm. The donor molecules contribute a FRET-based maximum IPCE of 25% with a corresponding excitation transfer efficiency of approximately 67.5%.

  8. HESS J1427-608: An Unusual Hard, Unbroken Gamma-Ray Spectrum in a Very Wide Energy Range

    Science.gov (United States)

    Guo, Xiao-Lei; Xin, Yu-Liang; Liao, Neng-Hui; Yuan, Qiang; Gao, Wei-Hong; He, Hao-Ning; Fan, Yi-Zhong; Liu, Si-Ming

    2017-01-01

    We report the detection of a GeV γ-ray source that spatially overlaps and is thus very likely associated with the unidentified very high energy (VHE) γ-ray source HESS J1427-608 with the Pass 8 data recorded by the Fermi Large Area Telescope. The photon spectrum of this source is best described by a power law with an index of 1.85 ± 0.17 in the energy range of 3-500 GeV, and the measured flux connects smoothly with that of HESS J1427-608 at a few hundred gigaelectronvolts. This source shows no significant extension and time variation. The broadband GeV to TeV emission over four decades of energies can be well fitted by a single power-law function with an index of 2.0, without obvious indication of spectral cutoff toward high energies. Such a result implies that HESS J1427-608 may be a PeV particle accelerator. We discuss the possible nature of HESS J1427-608 according to the multiwavelength spectral fittings. Given the relatively large errors, either a leptonic or a hadronic model can explain the multiwavelength data from radio to VHE γ-rays. The inferred magnetic field strength is a few micro-Gauss, which is smaller than the typical values of supernova remnants (SNRs) and is consistent with some pulsar wind nebulae (PWNe). On the other hand, the flat γ-ray spectrum is slightly different from typical PWNe but is similar to that of some known SNRs.

  9. A paper-based resonance energy transfer nucleic acid hybridization assay using upconversion nanoparticles as donors and quantum dots as acceptors

    Energy Technology Data Exchange (ETDEWEB)

    Doughan, Samer; Uddayasankar, Uvaraj; Krull, Ulrich J., E-mail: ulrich.krull@utoronto.ca

    2015-06-09

    Highlights: • Covalent immobilization of upconversion nanoparticles on paper. • LRET-based label free DNA detection using quantum dots as acceptors. • Use of polyethylene glycol to eliminate non-specific adsorption of quantum dots. • Improved analytical performance compared to analogous assays. - Abstract: Monodisperse aqueous upconverting nanoparticles (UCNPs) were covalently immobilized on aldehyde modified cellulose paper via reduction amination to develop a luminescence resonance energy transfer (LRET)-based nucleic acid hybridization assay. This first account of covalent immobilization of UCNPs on paper for a bioassay reports an optically responsive method that is sensitive, reproducible and robust. The immobilized UCNPs were decorated with oligonucleotide probes to capture HPRT1 housekeeping gene fragments, which in turn brought reporter conjugated quantum dots (QDs) in close proximity to the UCNPs for LRET. This sandwich assay could detect unlabeled oligonucleotide target, and had a limit of detection of 13 fmol and a dynamic range spanning nearly 3 orders of magnitude. The use of QDs, which are excellent LRET acceptors, demonstrated improved sensitivity, limit of detection, dynamic range and selectivity compared to similar assays that have used molecular fluorophores as acceptors. The selectivity of the assay was attributed to the decoration of the QDs with polyethylene glycol to eliminate non-specific adsorption. The kinetics of hybridization were determined to be diffusion limited and full signal development occurred within 3 min.

  10. Resonant energy transfer under the influence of the evanescent field from the metal.

    Science.gov (United States)

    Poudel, Amrit; Chen, Xin; Ratner, Mark A

    2017-06-28

    We present a quantum framework based on a density matrix of a dimer system to investigate the quantum dynamics of excitation energy transfer (EET) in the presence of the evanescent field from the metal and the phonon bath. Due to the spatial correlation of the electric field in the vicinity of the metal, the spectral density of the evanescent field is similar to that of a shared phonon bath. However, the EET dynamics under the influence of the evanescent field is an open and a new problem. Here we use a thin metallic film to investigate the effect of the evanescent field on the excitation energy transfer in a dimer system based on a density matrix approach. Our results indicate that a thin metallic film enhances the energy transfer rate at the expense of absorbing energy during the process. Since the spectral density of the evanescent field is affected by the geometry of the medium and the distance of a dimer system from the medium, our results demonstrate the possibility to tune EET based on material geometry and distances. Our model also serves as an expansion to quantum heat engine models and provides a framework to investigate the EET in light harvesting molecular networks under the influence of the evanescent field.

  11. Resonance Energy Transfer in Hybrid Devices in the Presence of a Surface

    DEFF Research Database (Denmark)

    Kopylov, Oleksii; Huck, Alexander; Kadkhodazadeh, Shima

    2014-01-01

    to approximately 10 nm was observed. By comparing the carrier dynamics of the quantum wells and the nanocrystals, we found that nonradiative recombination via surface states, generated during dry etching of the wafer, counteracts the nonradiative energy-transfer process to the nanocrystals and therefore decreases...

  12. Energy Moment Method Applied to Nuclear Quadrupole Splitting of Nuclear Magnetic Resonance Lines

    DEFF Research Database (Denmark)

    Frank, V

    1962-01-01

    Expressions giving the sum of the energy values, raised to the second and third power, for a nucleus interacting with a static magnetic field and a static electric field gradient are derived. Several applications of this method for obtaining the values of the components of the electric field...

  13. Resonant energy transfer under the influence of the evanescent field from the metal

    Science.gov (United States)

    Poudel, Amrit; Chen, Xin; Ratner, Mark A.

    2017-06-01

    We present a quantum framework based on a density matrix of a dimer system to investigate the quantum dynamics of excitation energy transfer (EET) in the presence of the evanescent field from the metal and the phonon bath. Due to the spatial correlation of the electric field in the vicinity of the metal, the spectral density of the evanescent field is similar to that of a shared phonon bath. However, the EET dynamics under the influence of the evanescent field is an open and a new problem. Here we use a thin metallic film to investigate the effect of the evanescent field on the excitation energy transfer in a dimer system based on a density matrix approach. Our results indicate that a thin metallic film enhances the energy transfer rate at the expense of absorbing energy during the process. Since the spectral density of the evanescent field is affected by the geometry of the medium and the distance of a dimer system from the medium, our results demonstrate the possibility to tune EET based on material geometry and distances. Our model also serves as an expansion to quantum heat engine models and provides a framework to investigate the EET in light harvesting molecular networks under the influence of the evanescent field.

  14. The function of the milk-clotting enzymes bovine and camel chymosin studied by a fluorescence resonance energy transfer assay.

    Science.gov (United States)

    Jensen, Jesper Langholm; Jacobsen, Jonas; Moss, Marcia L; Rasmussen, Fred; Qvist, Karsten Bruun; Larsen, Sine; van den Brink, Johannes M

    2015-05-01

    Enzymatic coagulation of bovine milk can be divided in 2 steps: an enzymatic step, in which the Phe105-Met106 bond of the milk protein bovine κ-casein is cleaved, and an aggregation step. The aspartic peptidases bovine and camel chymosin (EC 3.4.23.4) are typically used to catalyze the enzymatic step. The most commonly used method to study chymosin activity is the relative milk-clotting activity test that measures the end point of the enzymatic and aggregation step. This method showed that camel chymosin has a 2-fold higher milk-clotting activity toward bovine milk than bovine chymosin. To enable a study of the enzymatic step independent of the aggregation step, a fluorescence resonance energy transfer assay has been developed using a peptide substrate derived from the 98-108 sequence of bovine κ-casein. This assay and Michaelis-Menten kinetics were employed to determine the enzymatic activity of camel and bovine chymosin under milk clotting-like conditions (pH 6.65, ionic strength 80 mM). The results obtained show that the catalytic efficiency of camel chymosin is 3-fold higher than bovine chymosin. The substrate affinity and catalytic activity of bovine and camel chymosin increase at lower pH (6.00 and 5.50). The glycosylation of bovine and camel chymosin did not affect binding of the fluorescence resonance energy transfer substrate, but doubly glycosylated camel chymosin seems to have slightly higher catalytic efficiency. In the characterization of the enzymes, the developed assay is easier and faster to use than the traditionally used relative milk-clotting activity test method. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  15. Structural and biophysical characterisation of G protein-coupled receptor ligand binding using resonance energy transfer and fluorescent labelling techniques.

    Science.gov (United States)

    Ward, Richard J; Milligan, Graeme

    2014-01-01

    The interaction between ligands and the G protein-coupled receptors (GPCRs) to which they bind has long been the focus of intensive investigation. The signalling cascades triggered by receptor activation, due in most cases to ligand binding, are of great physiological and medical importance; indeed, GPCRs are targeted by in excess of 30% of small molecule therapeutic medicines. Attempts to identify further pharmacologically useful GPCR ligands, for receptors with known and unknown endogenous ligands, continue apace. In earlier days direct assessment of such interactions was restricted largely to the use of ligands incorporating radioactive isotope labels as this allowed detection of the ligand and monitoring its interaction with the GPCR. This use of such markers has continued with the development of ligands labelled with fluorophores and their application to the study of receptor-ligand interactions using both light microscopy and resonance energy transfer techniques, including homogenous time-resolved fluorescence resonance energy transfer. Details of ligand-receptor interactions via X-ray crystallography are advancing rapidly as methods suitable for routine production of substantial amounts and stabilised forms of GPCRs have been developed and there is hope that this may become as routine as the co-crystallisation of serine/threonine kinases with ligands, an approach that has facilitated widespread use of rapid structure-based ligand design. Conformational changes involved in the activation of GPCRs, widely predicted by biochemical and biophysical means, have inspired the development of intramolecular FRET-based sensor forms of GPCRs designed to investigate the events following ligand binding and resulting in a signal propagation across the cell membrane. Finally, a number of techniques are emerging in which ligand-GPCR binding can be studied in ways that, whilst indirect, are able to monitor its results in an unbiased and integrated manner. This article is part

  16. Resonance strength measurement at astrophysical energies: The {sup 17}O(p,α){sup 14}N reaction studied via Trojan Horse Method

    Energy Technology Data Exchange (ETDEWEB)

    Sergi, M. L., E-mail: sergi@lns.infn.it; La Cognata, M.; Pizzone, R. G. [INFN, Laboratori Nazionali del Sud, Catania (Italy); Spitaleri, C. [INFN, Laboratori Nazionali del Sud, Catania (Italy); Dipartimento di Fisica e Astronomia, Università degli studi di Catania, Catania (Italy); Lamia, L.; Rapisarda, G. G. [Dipartimento di Fisica e Astronomia, Università degli studi di Catania, Catania (Italy); Mukhamedzhanov, A. [Cyclotron Institute, Texas A& M University, College Station, Texas 77843 (United States); Irgaziev, B. [GIK Institute of Engineering Sciences and Technology, Topi, Districti Swabi, Khyber Pakhtunkhwa (Pakistan); Tang, X. D.; Wiescher, M. [Department of Physics, Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame 46556, Indiana (United States); Mrazek, J.; Kroha, V. [Nuclear Physics Institute of ASCR, Rez (Czech Republic)

    2015-10-15

    In recent years, the Trojan Horse Method (THM) has been used to investigate the low-energy cross sections of proton-induced reactions on {sup 17}O nuclei, overcoming extrapolation procedures and enhancement effects due to electron screening. We will report on the indirect study of the {sup 17}O(p,α){sup 14}N reaction via the THM by applying the approach developed for extracting the resonance strength of narrow resonance in the ultralow energy region. Two measurements will be described and the experimental THM cross sections will be shown for both experiments.

  17. Blinking fluorescence of single donor-acceptor pairs: important role of "dark'' states in resonance energy transfer via singlet levels.

    Science.gov (United States)

    Osad'ko, I S; Shchukina, A L

    2012-06-01

    The influence of triplet levels on Förster resonance energy transfer via singlet levels in donor-acceptor (D-A) pairs is studied. Four types of D-A pair are considered: (i) two-level donor and two-level acceptor, (ii) three-level donor and two-level acceptor, (iii) two-level donor and three-level acceptor, and (iv) three-level donor and three-level acceptor. If singlet-triplet transitions in a three-level acceptor molecule are ineffective, the energy transfer efficiency E=I_{A}/(I_{A}+I_{D}), where I_{D} and I_{A} are the average intensities of donor and acceptor fluorescence, can be described by the simple theoretical equation E(F)=FT_{D}/(1+FT_{D}). Here F is the rate of energy transfer, and T_{D} is the donor fluorescence lifetime. In accordance with the last equation, 100% of the donor electronic energy can be transferred to an acceptor molecule at FT_{D}≫1. However, if singlet-triplet transitions in a three-level acceptor molecule are effective, the energy transfer efficiency is described by another theoretical equation, E(F)=F[over ¯](F)T_{D}/[1+F[over ¯](F)T_{D}]. Here F[over ¯](F) is a function of F depending on singlet-triplet transitions in both donor and acceptor molecules. Expressions for the functions F[over ¯](F) are derived. In this case the energy transfer efficiency will be far from 100% even at FT_{D}≫1. The character of the intensity fluctuations of donor and acceptor fluorescence indicates which of the two equations for E(F) should be used to find the value of the rate F. Therefore, random time instants of photon emission in both donor and acceptor fluorescence are calculated by the Monte Carlo method for all four types of D-A pair. Theoretical expressions for start-stop correlators (waiting time distributions) in donor and acceptor fluorescence are derived. The probabilities w_{N}^{D}(t) and w_{N}^{A}(t) of finding N photons of donor and acceptor fluorescence in the time interval t are calculated for various values of the energy

  18. Stochastic resonance energy harvesting for a rotating shaft subject to random and periodic vibrations: influence of potential function asymmetry and frequency sweep

    Science.gov (United States)

    Kim, Hongjip; Che Tai, Wei; Zhou, Shengxi; Zuo, Lei

    2017-11-01

    Stochastic resonance is referred to as a physical phenomenon that is manifest in nonlinear systems whereby a weak periodic signal can be significantly amplified with the aid of inherent noise or vice versa. In this paper, stochastic resonance is considered to harvest energy from two typical vibrations in rotating shafts: random whirl vibration and periodic stick-slip vibration. Stick-slip vibrations impose a constant offset in centrifugal force and distort the potential function of the harvester, leading to potential function asymmetry. A numerical analysis based on a finite element method was conducted to investigate stochastic resonance with potential function asymmetry. Simulation results revealed that a harvester with symmetric potential function generates seven times higher power than that with asymmetric potential function. Furthermore, a frequency-sweep analysis also showed that stochastic resonance has hysteretic behavior, resulting in frequency difference between up-sweep and down-sweep excitations. An electromagnetic energy harvesting system was constructed to experimentally verify the numerical analysis. In contrast to traditional stochastic resonance harvesters, the proposed harvester uses magnetic force to compensate the offset in the centrifugal force. System identification was performed to obtain the parameters needed in the numerical analysis. With the identified parameters, the numerical simulations showed good agreement with the experiment results with around 10% error, which verified the effect of potential function asymmetry and frequency sweep excitation condition on stochastic resonance. Finally, attributed to compensating the centrifugal force offset, the proposed harvester generated nearly three times more open-circuit output voltage than its traditional counterpart.

  19. Understanding and modeling Förster-type resonance energy transfer (FRET) introduction to FRET

    CERN Document Server

    Govorov, Alexander; Demir, Hilmi Volkan

    2016-01-01

    This Brief presents a historical overview of the Förster-type nonradiative energy transfer and a compilation of important progress in FRET research, starting from Förster until today, along with a summary of the current state-of-the-art. Here the objective is to provide the reader with a complete account of important milestones in FRET studies and FRET applications as well as a picture of the current status.

  20. Forster Resonance Energy Transfer Between Core/Shell Quantum Dots and Bacteriorhodopsin

    Science.gov (United States)

    2012-01-01

    a wide range of the spectrum from ultraviolet to the visible and exhibit bright, atom-like narrow emission bands in the visible that can be further...biotin labeling on the purple membrane,” Journal of Photochemistry and Photobiology B, vol. 92, no. 2, pp. 123–127, 2008. [37] W. Z. Lee, G. W. Shu, J. S